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EddyCurrent
14-09-2013, 12:29 AM
Carries on from here

http://www.mycncuk.com/forums/diy-cnc-machine-building/6555-z-axis-appraisal-please.html


Right here's version 3 with the Z axis moved up into position

10111101121011310114



I assume your gantry will be 160mm high, that means for the 600mm travel you will use something like 1m of 160x12mm plate which weights 15kg. For example 1m 160x60x4mm steel profile weights 9 kg and would be stronger than your combined plate+aluminum profile.

I said I might add the plate. Are you talking about steel box section ? if you are the problem is it doesn't enclose the ball screw like the C shape.

JAZZCNC
14-09-2013, 12:46 AM
Bearings till look too close together on Z axis.?

I'd also re-think having the profile for gantry bearing plates it's just not flat enough or strong enough. Profiled linear bearings won't tolerate much error so these areas are important, the profile will bend and impart twist on the bearings making them bind. To give an idea of how little just the thickness of piece of paper can be the difference between binding and smooth running much more and easily locked up.!!

Boyan Silyavski
14-09-2013, 01:11 AM
I said I might add the plate. Are you talking about steel box section ? if you are the problem is it doesn't enclose the ball screw like the C shape.

Yes, i get it. I was suggesting a steel box section profile and 2x 30x30 or similar aluminum profiles fixed on one face so you can imitate your first design. Best would be your design made from steel box.

Looking at the design, what i see is that you try to make flat the z but at the same time the whole Z assembly seriously overhangs on the linear bearings. So making it same but from steel, you could fix the rails further in front up to the near end of the steel box, which you could not do with aluminum.

I have redrawn million times this and until now i couldn't find a real way to diminish overhang without placing the ball screw behind the gantry. For a better understanding is better to draw the spindle mount brackets, the spindle itself and the bit. On the 3d warehouse there is 2.2kw spindle with mounts. So you will have better picture what you gain and at what price and compare actual bit position.

-using flat wide rails 15 size on the Z will gain you 15mm versus 20 size square rails

EddyCurrent
14-09-2013, 10:37 AM
Bearings till look too close together on Z axis.?

Bearings now 150mm spacing, drawings show Z axis at extremes of travel.

1011510116


I'd also re-think having the profile for gantry bearing plates it's just not flat enough or strong enough. Profiled linear bearings won't tolerate much error so these areas are important, the profile will bend and impart twist on the bearings making them bind. To give an idea of how little just the thickness of piece of paper can be the difference between binding and smooth running much more and easily locked up.!!

Gantry rails are not on a profile it is steel box section to be bolted onto a base so it can be shimmed level. I've also read all about the epoxy leveling idea.

Listening to what silyavski is saying I've done an alternative for the Y rails, one pic shows the original position, the other shows the rail moved forward but is mounted over the inside vertical edge of the middle 80x40 extrusion instead of down the centre of it. I'm thinking the original is strongest.

1011710118

Questions
1. I mentioned earlier that due to the standard ball nut I need 4mm shims under 15mm bearing carriages on Z axis so should I fit 20mm bearings instead without shims?
2. Steel or aluminium for gantry ?
3. Anything else to amend ?

One I get the gantry finalised I can try to estimated the centre of gravity and get the X axis bearings better placed.

EddyCurrent
14-09-2013, 10:41 AM
Yes, i get it. I was suggesting a steel box section profile and 2x 30x30 or similar aluminum profiles fixed on one face so you can imitate your first design. Best would be your design made from steel box.

Looking at the design, what i see is that you try to make flat the z but at the same time the whole Z assembly seriously overhangs on the linear bearings. So making it same but from steel, you could fix the rails further in front up to the near end of the steel box, which you could not do with aluminum.

I have redrawn million times this and until now i couldn't find a real way to diminish overhang without placing the ball screw behind the gantry. For a better understanding is better to draw the spindle mount brackets, the spindle itself and the bit. On the 3d warehouse there is 2.2kw spindle with mounts. So you will have better picture what you gain and at what price and compare actual bit position.

-using flat wide rails 15 size on the Z will gain you 15mm versus 20 size square rails

I'll make a drawing to see what this is like, also estimate the weights. I've had a good play with the spreadsheet but it can't do the aluminium extrusion however there is another calculator for that.

JAZZCNC
14-09-2013, 06:23 PM
Gantry rails are not on a profile it is steel box section to be bolted onto a base so it can be shimmed level. I've also read all about the epoxy leveling idea.

Not talking about rails I'm talking about the profile you show the gantry sitting on, or should say sat on top of the X axis bearings.

Regards the rail position on the profile.? You are showing or presuming the profile is flat and smooth across it's surface but most i've used have some recess down the centre or between slots so you may find they interfere with plans.
Also if your using 15mm rail then you'll find the slots are wide with chamfered edges, this means the rail sits awkward and can cock when fastened down.

Q1: First are you sure you only need 4mm shims.? When I make Z axis even with 20mm profiled rails I need to machine approx 6-7mm channel down centre of both plates to give clearance for nut and bearings.?

Q2: Either.!!. . . . Steel is cheaper and strong but it resonates more so ideally needs filling . Profile is OK but not has strong and often not flat has folks realise and can make rail setup/alignment harder not easier like folks think.

EddyCurrent
14-09-2013, 08:35 PM
Spot on, I think there's enough info here and in the other current build logs to embark so I'm going to start ordering some stuff. Rather than add to this in dribs & drabs I'll update at strategic points in the build.
Hopefully I won't have to ask many more questions.

EddyCurrent
15-09-2013, 10:06 PM
On the other hand, went back to basics for a rethink, used spreadsheet and this set up should be very strong with not too much metal bashing.

Gantry width 1000mm, 80x80x3 steel box section
Gantry sides 120x80x5 steel box section with top open end plated.
All other plate 20mm aluminium
Rails mounted on front to remove need to have extra brackets if they were placed top and bottom.
150mm travel on Z axis.
Front could have thin slotted plate for chip protection or the whole front could have bellows fitted to cover rails as well.

Rail are spaced at 170mm centres and Z carriages are same spacing vertically
Y rails, not shown, mount directly under plate at bottom of gantry sides.
Hole for Y ballscrew to exit at one end (not shown) may require double plating around it for strength.

Any thoughts on this ? especially best way to engineer the various butt joints at end of each box section.

1013410135

JAZZCNC
15-09-2013, 11:31 PM
Yep that's getting better.!. . . couple of things worth a mention.?

The way you have ballscrews fixed into gantry ends using FF/FK blocks will cause you problems with alignment and getting in and out because it's effectively trapped.
With this design you'll be better with BK/BF blocks either sat on box section or fasten thru sides of blocks into ends.

How you going to fasten the 120x80 box to those plates which I presume are Aluminium.? You'll have to make sure those ends are cut or machined perfectly 90deg otherwise they'll be a pain and if you weld plates on ends and bolt into Aluminium the plate will need milling perfectly flat.

Fastening the ends to gantry box section will also need careful end machining and attention, Esp if bolted together. If you weld it together you'll need to pay very careful attention to it twisting. . . . Personally I'd weld it together then Epoxy level the front so both rails are on the same plane. This way doesn't matter if it twists has the epoxy will remove any so all you need to ensure is that it's square which is easy done with careful measurement.

I'd also increase those little up stand brackets, basicly make them triangles that go at least half way up the Box section height.

EddyCurrent
15-09-2013, 11:46 PM
The way you have ballscrews fixed into gantry ends using FF/FK blocks will cause you problems with alignment and getting in and out because it's effectively trapped.
With this design you'll be better with BK/BF blocks either sat on box section or fasten thru sides of blocks into ends.

You're right, I was thinking the gantry sides might be bolted together thus allowing access to fit the ball screw.



How you going to fasten the 120x80 box to those plates which I presume are Aluminium.? You'll have to make sure those ends are cut or machined perfectly 90deg otherwise they'll be a pain and if you weld plates on ends and bolt into Aluminium the plate will need milling perfectly flat.

I can see the 90deg aspect will be a problem whatever method of construction is used. I was thinking of bolting a block to the aluminium that was a tight fit into the box section, then bolt the box section to the block. Welding a bottom plate as you say and milling might be a better idea.


Fastening the ends to gantry box section will also need careful end machining and attention, Esp if bolted together. If you weld it together you'll need to pay very careful attention to it twisting. . . . Personally I'd weld it together then Epoxy level the front so both rails are on the same plane. This way doesn't matter if it twists has the epoxy will remove any so all you need to ensure is that it's square which is easy done with careful measurement.

I was thinking welding would be best, I would make a jig to hold it.


I'd also increase those little up stand brackets, basicly make them triangles that go at least half way up the Box section height.

I had them like that at first, will change back.

Clive S
16-09-2013, 12:03 AM
Have you thought how you will bolt the Z rail blocks and the Y rail blocks on as they appear to clash with each other. It might be better to make the Z back plate wider. ..Clive

EddyCurrent
16-09-2013, 12:11 AM
Have you thought how you will bolt the Z rail blocks and the Y rail blocks on as they appear to clash with each other. It might be better to make the Z back plate wider. ..Clive

Thanks, they are kind of close but the bolt holes don't line up so I was thinking they would bolt onto tapped holes in the plate with hex head screws from their own respective sides but as I've never fitted them before it's just a plan until I get the hardware in front of me. Widening the plate would be a useful option.

JAZZCNC
16-09-2013, 12:25 AM
Thanks, they are kind of close but the bolt holes don't line up so I was thinking they would bolt onto tapped holes in the plate with hex head screws from their own respective sides but as I've never fitted them before it's just a plan until I get the hardware in front of me. Widening the plate would be a useful option.

I missed this which is unusual for me has it happens often so I'm always watching for it but you didn't have it like that before so didn't pay any attention this time.!! . . . . . Clives correct thou you can't do it you'll need to lower/lift or widen. . . Chicken and Egg problem.???

Regards 90Deg problem then yes needs same attention but milling ends of 80mm box section will need big mill with large tooling. Having plates for gantry sides which bolt to base plate and are held 90deg with bracing brackets is much easier to do.

Welding will be good but will still possibly try to twist when released from Jig. Even then you can't be 100% sure faces of both box sections are exactly on same plane and that's why I'd use epoxy in this situation.

EddyCurrent
16-09-2013, 09:11 AM
The reason I used box section for gantry sides was due to large strength advantage over plates.

I thought this might be an idea for attachment of sides to aluminium.

10139

By welding a plate (with nuts welded to the back of it) about 6mm in from the end of the box section, I could easily file the box profile edges to 90deg. I suppose you could then fill the 6mm deep cavity with epoxy if need be. Maybe use 1/2" plate and drill & tap 4 holes instead of welding nuts behind a thinner plate.
Epoxy plan for gantry horizontal members will be fine.

10151

1. Ball screw bearings moved to outside of frame or as suggested I might use BK/BF instead.
2. Support brackets for sides increased in size
3. I think you are saying that to fit the bearing blocks I need to drill through the ally backplate and use nuts & bolts rather than tapping the backplate and screwing in from each side with set studs ?

EddyCurrent
22-09-2013, 05:38 PM
Metal ordered, ball screws etc. ordered (Chai), pondering HIWIN or similar guides but Zapp is easiest to order these from and they have exact lengths I need without having to cut them. Also I (re)decided that I didn't really want a challenge building this machine, I just want it to work as planned so I can use it. With this in mind then I reverted back to the L gantry which I earlier said I didn't like :ambivalence: but it simplifies the making of it quite a bit. It will be something like Matt's (kingcreaky) machine with a few changes.

Jonathan
22-09-2013, 07:42 PM
Metal ordered, ball screws etc. ordered (Chai), pondering HIWIN or similar guides but Zapp is easiest to order these from and they have exact lengths I need without having to cut them.

Since it seems you're happy to get the rest of the linear motion parts from China, I'm surprised at your choice of supplier for the linear guides. There are quite a few sellers on aliexpress which sell them for a lot less. For example:

BST AUTOMATION - Small Orders Online Store, Hot Selling Ball screws,ballscrew,linear guide and more on Aliexpress.com (http://www.aliexpress.com/store/314742)

Just send them a message with the lengths you want, and make sure you get the right preload - i.e. not zero.

EddyCurrent
22-09-2013, 08:10 PM
I didn't ask Chai about the rails because on ebay he seemed to be selling only round rail. I looked at Aliexpress and that's why I'm pondering, sometimes I just like it easy rather than cheapest.

EddyCurrent
06-10-2013, 11:40 PM
Ball screws etc. arrived from Chai all machined exactly to my spec. with dimension F extended to 30mm for pulley.
Decided to get Hiwin rails and blocks from UK but not from supplier I was thinking about, arrived within 2 days, great !

EddyCurrent
07-10-2013, 04:40 PM
This weekend got the Ethernet Smooth Stepper, BOB (DIYCNC), Spindle board (DIYCNC), 5v and 24vpower supplies.
Lashed them together and plugged into PC, it took a while to get it sorted as this is the first time I've used Mach3 and the hardware but by afternoon had everything working and the inputs set up as per my drawings. Need to get the control cabinet layout finished so I can order the right size box. Having to wait for the AM882's coming in.
Also got the main power supply transformer, 22000uF capacitor, bridge rectifier, aluminium plate to mount it.
Nearly got the bottom frame design finished and have all the metal ready to start cutting, Brother-in-law booked in with his MIG.

EddyCurrent
20-10-2013, 05:42 PM
I've just been reading about roof truss design and used the info to finish my frame.
All box section is 50x50x3 steel except that in blue which is 100x50x3.
Red plates are 10mm steel
Yellow gussets are 6mm steel

Any thoughts ? and keep in mind the fairly small overall dimensions.

1046510466

JAZZCNC
20-10-2013, 10:35 PM
Looks good Eddy Only thing I'd change is to add another support for the bed.

Be careful when welding the diagonals where they meet in the centre, don't weld both at same time has you'll be putting a lot of heat in one spot.

Jonathan
20-10-2013, 10:37 PM
Yeah, I was thinking it look fine but might as well add another vertical piece in the center of the 100x50 box section on both sides. The diagonals are already supporting it well though, so if adding a support to the center you could possibly make the diagonals shorter if it ends up more convenient when it comes to ordering the steel.

JAZZCNC
20-10-2013, 10:50 PM
Yeah, I was thinking it look fine but might as well add another vertical piece in the center of the 100x50 box section on both sides. The diagonals are already supporting it well though, so if adding a support to the center you could possibly make the diagonals shorter if it ends up more convenient when it comes to ordering the steel.

Think it might benefit from a combination of both, centre vertical and shorter diagonals along with more bed supports. The diagonals would then fall in-line and support the extra bed supports and the vertical would support centre.
The shorter diagnols would then make it so you could add shelf if needed and not impede so much.?

Out of both suggestions the extra bed supports is the one I'd deem most beneficial.!

EddyCurrent
21-10-2013, 10:23 AM
Thanks for the feedback.
At first I had a centre vertical but after reading about the roof trusses where forces are pressing down from the top it is redundant for all practical purposes, force are directed down the diagonals into the legs, of course this only applies if the diagonals are within a particular angle to vertical which in my case they are. The mantra for the trusses was to create triangles, which I'm sure we all know about.
I'll have another look at a centre vertical and two shorter diagonals and see what it looks like, I'm trying to keep material to a minimum although as with a workbench it's best to have a bit of weight about it.
Now I look at it again I can see the bed needs more support so I'll add two more intermediate cross members.

The welding plan is to tack it all round then do like bolting a cylinder head down by jumping around apposing joints to fully weld them, hopefully this will prevent too much heat build up in one area.

Edit: new options added, what's the verdict on best option ? ( just measured and there's less material in Option 2 )

Option 1 - side diagonals only + extra bed cross members

10472

Option 2 - centre vertical, smaller diagonals moved to meet new bed cross members + extra bed cross members

10473 10474

FatFreddie
21-10-2013, 02:53 PM
For me, option 1 looks better since the triangulation supports the point where the top rails attach. If you want to save material you could go for smaller section tube for the triangulation pieces and the bottom rails since there should be little or no bending moment there. If you want more stiffness you could triangulate each bed rail the same way you have done at the ends.

EddyCurrent
21-10-2013, 04:12 PM
Thanks, Yes I think you are correct about using smaller section for some parts but I already have the material shown and I'm only wanting to save material to keep the weight down rather than cost.
It's probably fair to say either option would be fine so I'll see if anyone else is kind enough to give their judgment first.

Boyan Silyavski
21-10-2013, 04:15 PM
Hi Eddy,

for sure you know from the other threads already my preference is not for that type of design, i like 80x80 and 100x100 x 3mm, but your design looks ok for the job intended.

However just some points from design and strength point of view. Forget about the 1m more or less for a moment, as this profile is not so costly or heavy.

The main principles should be: simple, all parts under equal load , no parts that transmit the flex from above to the same place bellow, divide and conquer/strengthen :-) / and no parts that serve only one purpose, so:

-look at drawing 1 and 2 . The bar at the lower part that is in the middle of the rectangular. I don't like it. If there were 2 of them , they would keep the table from twist. Now that is only one in the middle, it just holds both long sides at same distance. Not only that but transmits the flex from above in the same place bellow. And separates only in 2 the long sides.
i would put 2 of them or none, instead solder 4 diagonals in such a way that the long and the short sides are separated each in 3 equal pieces, or somewhere near it

-diagonals on the sides on 1, separate the upper rail support only in 2 pieces, and on drawing 2, they separate the upper rail support onto 3 pieces but not equal and also are soldered very high on the legs.

that leads me to the next
-the middle side support in drawing 2 does exactly what should not be done, transmit the flex from the middle on the exactly same place bellow.

Solutions? Think in arcs. Like the door of a stone house or castle or so. 1 short horizontal bar each from one side, soldered 15cm below the rail supports directly to the previously suggested diagonals position will strengthen the arc, permit the diagonals to go lower at their low ends, and that combined with the removal of the middle vertical bar and replacing the bottom middle bar with diagonals will make everything stronger, resistant to twist and most importantly remove any push from the lower rectangular replacing it with pull, which in fact is way stronger. Or no horizontal bars , the rails supports are double and look quite strong in vertical direction...You can pull a lot but push very little :-)

Just an idea how my thoughts go, there are other ways to do it also. It would work like this and like that, though there is quite a satisfaction achieving some perfect shape!

PS. Lowering the diagonals on the sides will achieve the following. Now if pressure is applied from above in the middle, the diagonals push the legs in the middle and try to bend them. If slightly lowered their end, they will start pulling the lower part long sides and remove the push from the legs.

EddyCurrent
21-10-2013, 05:29 PM
instead solder 4 diagonals in such a way that the long and the short sides are separated each in 3 equal pieces, or somewhere near it


Solutions? Think in arcs. Like the door of a stone house or castle or so. 1 short horizontal bar each from one side, soldered 15cm below the rail supports directly to the previously suggested diagonals position will strengthen the arc, permit the diagonals to go lower at their low ends, and that combined with the removal of the middle vertical bar and replacing the bottom middle bar with diagonals will make everything stronger, resistant to twist and most importantly remove any push from the lower rectangular replacing it with pull, which in fact is way stronger. Or no horizontal bars , the rails supports are double and look quite strong in vertical direction...You can pull a lot but push very little :-)

silyavski, I knew you could not resist to comment on a frame design :welcoming:

I got the first part but I'm sorry I did not fully understand how to draw everything you said in the second part, but here is some of it

10484

Boyan Silyavski
21-10-2013, 05:46 PM
silyavski, I knew you could not resist to comment on a frame design :welcoming:

I got the first part but I'm sorry I did not fully understand how to draw everything you said in the second part, but here is some of it

10484

It was irresistible :monkey:

Sorry about my English.

I meant what you did to the sides to do it at the base square and remove the middle piece / the plane at the bottom, the bottom horizontal rectangular plane i am talking/

At the long side planes which you changed, remove the lower 2 diagonals and solder there what you call gussets instead /yellow/. And now that the 2 remaining diagonals are ok at their upper ends, make them longer below to go and touch to 20cm up, measured from the bottom of the legs. Dont move their upper ends

Make same at your short side vertical planes/ the face of the machine and the back/ and there you have it. Here you should shorten more the diagonals and make them touch 20cm from bottom or even higher.

EddyCurrent
21-10-2013, 06:33 PM
Don't be sorry for your English it's fine, it's not easy to explain this thing exactly.

I think this is how you mean

Option 3

10485

So for anyone else there are now 3 options, this one and two in post #24

EddyCurrent
12-11-2013, 09:05 PM
How many people build the control panel first ? Just got it finished today, I decided I would wire the spindle cable directly to the Inverter later on without going through a set of terminals.
The door interlocked isolator is in a position I would not normally use but layout and segregation of components dictated the design.
I'll also install a cooling fan at the bottom blowing air into the enclosure via a replaceable filter and an outlet at the top. It's better to blow air in, than suck it out, this maintains a positive pressure inside the enclosure keeping crap out, the only access point being through the filter.

10719 10720

I came across these handy automotive fuse holders, ideal to individually supply and protect each stepper driver from your power supply. While sold as 12volt I decided they would be perfectly fine for the 60 volts I am using but you should decide yourself if you think about using them.

2/4/6/8/10/12 WAY + HEAVY DUTY AUTO FUSE BOX/HOLDER 12V VOLT STANDARD BLADE | eBay (http://www.ebay.co.uk/itm/2-4-6-8-10-12-WAY-HEAVY-DUTY-AUTO-FUSE-BOX-HOLDER-12V-VOLT-STANDARD-BLADE-/321061386290?pt=UK_WSJL_Wholesale_GL&var=&hash=item4ac0bff832)

cncJim
13-11-2013, 12:01 PM
How many people build the control panel first ? Just got it finished today, I decided I would wire the spindle cable directly to the Inverter later on without going through a set of terminals.

Wow eddy, that's a great looking control panel! I am especially interested as I am in the process of boxing up all of my hardware (currently all screwed to a bit of old mdf that has seen better days!).

I would love to know a bit more:-



I decided I would wire the spindle cable directly to the Inverter later on without going through a set of terminals.
Do you mean rather than going INVERTER -> Through the conduit -> DIN mounted terminal -> panel mounted connector, you will be skipping the conduit/DIN terminal and wire straight to the panel connector? Is this to reduce the chance of noise/interference?


Do you have any wiring diagrams you would care to share? I can identify some of the components in your pic and guess how some connect but a bit more detail would be great.


Where are you planning to mount the various connectors? I guess the bottom panel?

I see you have an EStop on the front but do you have any other provision for machine mounted estops/limit switches/home switches?

Are those grey jobbies at the bottom din mounted terminal blocks?


Can you recommend a supplier for the various parts (DIN rail, cable conduit etc)?


Sorry for all the questions, just very interested!
Thanks again for sharing the pics Eddy! :thumsup:

EddyCurrent
13-11-2013, 03:48 PM
Wow eddy, that's a great looking control panel!

Thanks


Do you mean rather than going INVERTER -> Through the conduit -> DIN mounted terminal -> panel mounted connector, you will be skipping the conduit/DIN terminal and wire straight to the panel connector? Is this to reduce the chance of noise/interference?

Yes and Yes


Do you have any wiring diagrams you would care to share? I can identify some of the components in your pic and guess how some connect but a bit more detail would be great.

1072110722107231072410725


Where are you planning to mount the various connectors? I guess the bottom panel?

No connectors, I'll be glanding off the cables at the bottom and wiring into the DIN rail mounted terminals


I see you have an EStop on the front but do you have any other provision for machine mounted estops/limit switches/home switches?

See drawing, yes, I'll probably include in the E/stop circuit the following; ultimate travel limits, machine mounted E/stop button, spindle motor over temperature sensor, AM882 alarms.
The homing limits are wired separately they are not in the E/stop circuit.


Are those grey jobbies at the bottom din mounted terminal blocks?

Yes, the earth terminals provide an easy way to tie all the screens down.



Can you recommend a supplier for the various parts (DIN rail, cable conduit etc)?

These may not be the ultimate cheapest but won't be far off, I was surprised how Farnell prices have improved lately for some items, or maybe it's others bumping theirs up ?

Home - Chalon Components (http://www.chaloncomponents.co.uk) - various bits and pieces
Farnell United Kingdom | Electronic Components | Electronic Parts (http://uk.farnell.com) - DIN rail, trunking, other small bits
Quickbit (http://quickbit.co.uk) - CY cable
Electronic Components from Rapid - the Electronic Parts Specialist (http://www.rapidonline.com) - small power supplies, large capacitor
Transformer Manufacturer UK - Airlink Transformers (http://www.airlinktransformers.com) - toroidal transformer

cncJim
13-11-2013, 05:03 PM
Thanks again Eddy, you have saved me many hours/days of Googling!



What software did you use for your wiring diagrams? Looks very good and easy to follow.


“No connectors, I'll be glanding off the cables at the bottom and wiring into the DIN rail mounted terminals”
Of course! I have been specing out the various connectors I would be needing to hook everything up (not cheap!) but this way make far more sense! Even more so the fact that I plan to fix my control panel under the machine. Doh! :stupid:


Do you plan to have any control for things like Air/Water/Vacuum in the panel or maybe just have them switchable on the machine? I plan to have them all individually controllable (ON-OFF-ON with spindle).

I like the idea for the spindle motor over temp. Have decided how you will implement this at the spindle?


Also I spotted your link to the “System Design for Control of Electrical Noise” pdf in another post. Just been reading it, great info, particularly the parts dealing with “clean/dirty/very dirty” cable runs. Very interesting.

Maybe not so much use in your case Eddy (?), but in case anyone else finds it useful I found a neat cable entry wiring solution for cabinets - Great for things like the parallel port cable:-
Weidmuller Cabtite (http://www.weidmuller.co.uk/69949/Products/Power,-Signal,-Data/cw_index_v2.aspx)
10726

EddyCurrent
13-11-2013, 05:30 PM
What software did you use for your wiring diagrams? Looks very good and easy to follow.

Visio but any 2D CAD will do, it's just that I had already created the symbols with it. By the way a good source for electrical symbols is the Telemecanique catalogue, you have to draw them youself and save as a block but it's still a great resource.


Do you plan to have any control for things like Air/Water/Vacuum in the panel or maybe just have them switchable on the machine? I plan to have them all individually controllable (ON-OFF-ON with spindle).

No not particularly but I have included some spare terminals if need be with the idea of adding another breakout board, the Smooth Stepper has connectors for 3 ports. The enclosure is pretty full now and I like everything to fit onto the backplate, other than door mounted buttons etc.


I like the idea for the spindle motor over temp. Have decided how you will implement this at the spindle?

The spindle is an ELTE 2.2kw TMPE3 12/2 and has a built in switch for temperature.


Also I spotted your link to the “System Design for Control of Electrical Noise” pdf in another post. Just been reading it, great info, particularly the parts dealing with “clean/dirty/very dirty” cable runs. Very interesting.

In my panel all the low level signal wires go in the right hand vertical trunking while the stepper motor and power wiring are in the left hand vertical trunking. The stepper motor wiring and spindle motor wiring are in screened CY cable, all screens earthed at the terminal rail and nowhere else.
If anyone is concerned, it might be worth their while to look up IP2X for electrical panels, one way is to put a full perspex sheet over the whole guts secured by screws at the corners.

JAZZCNC
14-11-2013, 03:07 AM
Eddy Save your self some inputs and just wire the Home and limits in series. If using separate home switches to limits you'll just need 2 inputs and if sharing same switch just one.!

Not sure if your aware or not but by default when Mach homes it just moves one axis at a time so can be wired in series with no problems. You only need on separate Inputs if you change the homing script so all Axis home together. It's actually better leaving in default mode because it's very easy to damage tools etc because when you press Ref all home then all 3/4 axis set off homing at same time and it's very easy for tool to catch something because the Z axis hasn't lifted enough before X or Y drag it into clamps or material etc.
Mach's default homing first lifts the Z axis then Y axis followed by X axis making it safe. In practice when wired in series this also means tripping any switch can set the axis being homed at that time.? Ie pressing X axis switch while Z axis is homing still sets Z axis home position.? Mach doesn't know or care which switch is pressed, all it cares about is seeing the input state change then setting the coordinates for the axis it was homing at that time then moves onto the next axis etc.

Also spotted you have the ABB 355 vfd same has me. I don't see any reference to the water pump on your schematic and I also don't see any reference to it from the VFD so not sure if your using WC spindle or not.? . . But What I do is use the On board relay on the VFD to turn pump on/off this way it's only on while spindle is spinning.

EddyCurrent
14-11-2013, 09:34 AM
Eddy Save your self some inputs and just wire the Home and limits in series. If using separate home switches to limits you'll just need 2 inputs and if sharing same switch just one.!

Thanks, yes, I found out about that while testing the setup here.
http://www.mycncuk.com/forums/marketplace-discussion/6528-csmio-ip-m-vs-ethernet-smoothstepper-begone-foul-parallel-port-2.html#post51374


Also spotted you have the ABB 355 vfd same has me. I don't see any reference to the water pump on your schematic and I also don't see any reference to it from the VFD so not sure if your using WC spindle or not.? . . But What I do is use the On board relay on the VFD to turn pump on/off this way it's only on while spindle is spinning.

Air cooled ELTE spindle, yes good idea to use the relay for that.

cncJim
14-11-2013, 11:42 AM
Visio but any 2D CAD will do, it's just that I had already created the symbols with it. By the way a good source for electrical symbols is the Telemecanique catalogue, you have to draw them youself and save as a block but it's still a great resource.

Ah ok - I have access to visio so I guess its time to learn how to use it!



The spindle is an ELTE 2.2kw TMPE3 12/2 and has a built in switch for temperature.

That's interesting. I was thinking about this and is it a good idea to have the spindle over temperature hooked into the estop circuit? My thinking being that if the spindle starts to over heat, I would for sure like to be made aware of it but I wouldn't the whole machine to emergency stop and risk damage (would anything potentially be damaged as a result of an estop or have I got the wrong end of the stick? I have read different things/advice so far. Obviously if it was a real emergency then damage to the equipment is the last thing to worry about). Maybe a two stage system with a warning buzzer/light when the temp hits the first level and then estop if it rises to the next level? Sorry just thinking out loud!
*



In my panel all the low level signal wires go in the right hand vertical trunking while the stepper motor and power wiring are in the left hand vertical trunking. The stepper motor wiring and spindle motor wiring are in screened CY cable, all screens earthed at the terminal rail and nowhere else.
If anyone is concerned, it might be worth their while to look up IP2X for electrical panels, one way is to put a full perspex sheet over the whole guts secured by screws at the corners.

I think that is how I will approach the wiring. Thanks for the reminder on IP. Many years ago I used to work in electrical testing and I can just about remember some of the testing we used to do for IP.

EddyCurrent
14-11-2013, 01:45 PM
That's interesting. I was thinking about this and is it a good idea to have the spindle over temperature hooked into the estop circuit? My thinking being that if the spindle starts to over heat, I would for sure like to be made aware of it but I wouldn't the whole machine to emergency stop and risk damage (would anything potentially be damaged as a result of an estop or have I got the wrong end of the stick? I have read different things/advice so far. Obviously if it was a real emergency then damage to the equipment is the last thing to worry about). Maybe a two stage system with a warning buzzer/light when the temp hits the first level and then estop if it rises to the next level? Sorry just thinking out loud!

Yes this crossed my mind, I may change this strategy at some point. To be honest I just included that option at the last minute without much thought. Just a quick thought, maybe if it was an input to the breakout board it could tell Mach3 to close down in an orderly fashion home itself then stop the machine.

Following Dean's reply and also my tests in another thread I have updated 2 of the drawings so that the X,Y,Z home limits are in series but the A home limit needs to be separate because it's slaved off X as I'm using 2 individual motors driving two ball screws. I'll still bring 2 core cables back from each switch to the machine mounted terminal box but I'll series them up at the terminal rail. (leaves option for later if need be)

1073010731

With regard to safety, final, ultimate limits (whatever you want to call them) then it is not a good idea to involve software which is why I have them in the hardware E/stop circuit.

cncJim
14-11-2013, 02:18 PM
Yes this crossed my mind, I may change this strategy at some point. To be honest I just included that option at the last minute without much thought. Just a quick thought, maybe if it was an input to the breakout board it could tell Mach3 to close down in an orderly fashion home itself then stop the machine.

Nice thought! As a result of the input would it be possible instruct Mach to issue a Feedhold, raise to safe z and shutdown the spindle? Would be nice to be able to continue the job after checking things out?



Following Dean's reply and also my tests in another thread I have updated 2 of the drawings so that the X,Y,Z home limits are in series but the A home limit needs to be separate because it's slaved off X as I'm using 2 individual motors driving two ball screws. I'll still bring 2 core cables back from each switch to the machine mounted terminal box but I'll series them up at the terminal rail. (leaves option for later if need be)

My machine also uses two motors driving x - interesting to see how this should be wired.



I'll still bring 2 core cables back from each switch to the machine mounted terminal box but I'll series them up at the terminal rail. (leaves option for later if need be)

That's a good idea. I have quite a bit of Cat5 cable and I was thinking of using this. Figured the twisted pairs would be good for noise rejection. Second thought, the Cat5 is also shielded but I am thinking the cable may be too bulky/stiff...



With regard to safety, final, ultimate limits (whatever you want to call them) then it is not a good idea to involve software which is why I have them in the hardware E/stop circuit.

Agreed - I haven't designed my safety circuit yet but was planning on basing it on the example circuit in the Mach 3 manual.
10732

EddyCurrent
14-11-2013, 03:08 PM
My breakout board has a charge pump output that I'm currently not using. Mach3 is using it but I think I will look at incorporating it into the hardware stop circuit as your drawing shows.
Also, and this is very important but open to interpretation, I am not removing power from the spindle inverter during emergency stop, I mentioned this is another post. The reason is that the inverter can stop the spindle faster than it will stop on it's own, it does this by applying dynamic braking. Other options for bringing the spindle to a timely halt would be a spring loaded mechanical brake or as in the case of my table saw, a DC injection braking system. Removing power to the inverter via a contactor is the obvious emergency stop strategy and it could be said that removing power from the inverter under load will damage it, that might be true but better to have a damaged inverter than a damaged limb. According to the machinery Regs. which won't apply in a private houshold situation, the spindle should stop within 10 seconds, now I've not had my spindle up to speed yet so time will tell how long it takes to stop on it's own.

cncJim
14-11-2013, 04:49 PM
Also, and this is very important but open to interpretation, I am not removing power from the spindle inverter during emergency stop, I mentioned this is another post. The reason is that the inverter can stop the spindle faster than it will stop on it's own, it does this by applying dynamic braking. Other options for bringing the spindle to a timely halt would be a spring loaded mechanical brake or as in the case of my table saw, a DC injection braking system. Removing power to the inverter via a contactor is the obvious emergency stop strategy and it could be said that removing power from the inverter under load will damage it, that might be true but better to have a damaged inverter than a damaged limb. According to the machinery Regs. which won't apply in a private houshold situation, the spindle should stop within 10 seconds, now I've not had my spindle up to speed yet so time will tell how long it takes to stop on it's own.

Good info, thanks.
If I had your VFD rather than my cheap Chinese one, I might be more inclined to trust it to stop the spindle during an Estop as well. :courage:



Removing power to the inverter via a contactor is the obvious emergency stop strategy and it could be said that removing power from the inverter under load will damage it, that might be true but better to have a damaged inverter than a damaged limb.
Why would the inverter be damaged in this situation? Is it because once the power is cut to the inverter the spindle acts as a generator and this generated current can damage the inverter?

I would like to have a safety system that does not compromise at all on safety but has the best chance on leaving the equipment undamaged (also how do you test an estop circuit if testing it may damage the equipment?!?).

I'm not that keen on the mechanical breaking solution, so that leaves the following:-

EStop

Dynamic/Rheostatic braking
Cut cables from inverter to spindle and attach spindle to a bank of breaking resisters to apply dynamic breaking (is this even how it works!?!). At same time cut the run cable to the inverter.
DC injection braking system
Same as above but DC injection brake cuts the link from inverter to spindle and applies DC to the spindle to stop it.


I like the idea of the DC injection braking system but they seem pretty expensive (RS DC Injection Brake (http://uk.rs-online.com/web/p/brake-modules/2096384/?origin=PSF_421227|alt) @ ~160 with VAT!). I wonder how easy/cheap it would be to do dynamic braking (without the vfd)?

edit - Just noticed my Huanyang vfd has terminals to add a braking resistor. If power is removed from the inverter would this still be used/effective? would it cause damage to the inverter?

EddyCurrent
14-11-2013, 06:21 PM
Some reading.

LPC Siemens Micromaster440 (http://www.lpc-uk.com/siemens/sensors/switoff.htm)
HMK Direct High Performance Drives and Positioning Systems (http://www.hmkdirect.com/downloads/Electrical/Drives/Inverter/Siemens/Sinamics/G120/Sales/Information/safety_standard_drives_simplified.pdf)
Motor drives & safety interlock circuits: AC Drives: FAQ (part 3) (http://www.industrial-electronics.com/output_devices_amplifiers_valves_relays_variable-frequency_drives_stepper_motors_servomotors/AC-drives-FAQ-3.html)
Variable Speed Drives - E-stop (http://www.control.com/thread/1026234414)

My conclusion is that when someone hits the emergency stop button the drive control signals must instantly tell the drive to stop and after a short delay the power is removed from the drive input via a suitable contactor. A braking resistor would be used to slow down the load as quickly as possible but as far as I'm aware it would only be operational if the drive was powered up.
As it happens the ABB drive I'm using has the STO function built in. I'll add a new drawing ASAP.

JAZZCNC
14-11-2013, 07:24 PM
Ok lets have a reality check.!!

The spindle is a low powered affair, even at 2.2Kw and if the shit hit's the fan then reality is the situation will be one of just few things gone wrong.
E-stop is hit due to Limit or some other none spindle related condition then doesn't really matter how long spindle takes to slow down and coasting to a stop isn't long or problem.
E-stop is hit due to tool sticking etc then bloody thing will have stopped anyway or will grind to a halt dam quick.!!
E-stop is hit because you have been stupid enough to stick a hand or some other bodily part in the spindle then Yes you'll want the Spindle to stop quick has possibly but again your flesh or clothing will do a good job of acting has a braking and the spindle isn't powerful and doesn't have massive torque so will stall.!! . . So what I'm saying is the VFD's built in DC braking will be enough no resistor required.

Now regards the Kill power or Kill signal to VFD then I used to be Kill Signal guy but I'm now I Kill all power. Reason being what happens if the signal breaks or Even the VFD goes faulty.? Kill power and all doubt is removed. In practice the reality is the spindle will be jammed, either in material or flesh or in a situation where doesn't affect safety and the DC braking allowed without need for a resistor is more than enough.

For DIY use then it's more than good enough to just kill power and Let the spindle coast.

EddyCurrent
14-11-2013, 08:20 PM
Dean, you are correct in that every situation has to be risk assessed on it's own.
I also think the braking resistor is not required because of the fairly low inertia of the load.
I agree that for DIY either strategy is fine but maybe not everyone reading this is in a DIY situation, in which case they should be referring to the relevant regulations.
The main aim of this is to get a good emergency stop system using the gear we've got.

It would be useful if we could define some scenarios and strategies for stopping a cnc machine, your input is valuable here.

I've listed some ways to stop the machine and the strategy to adopt, I'm not saying it's comprehensive so please add or amend as you think.

*emergency stop button pressed - strategy 1 or 2
*limit switch activated (not home limits) - strategy 2
*spindle over temperature switch activated - strategy 3
*Stepper driver alarm relay activated (e.g. AM882) - strategy 3
*'Stop' button pressed - strategy 4
*Charge Pump error - strategy 1 or 2

Strategy 1
----------
* remove power to all devices immediately

Strategy 2
----------
* remove power to stepper drives immediately
* remove power to ancillary devices immediately e.g. air, water, dust extraction
* issue stop command to VFD then after delay remove power to VFD

Strategy 3
----------
* issue audio visual alarm before taking action (with time delay)
* controlled stopping of all machine actuators and ancillary devices
* leave power supply on to VFD

Strategy 4
----------
* controlled stopping of all machine actuators and ancillary devices
* leave power supply on to VFD

Jonathan
15-11-2013, 12:55 AM
Removing power to the inverter via a contactor is the obvious emergency stop strategy and it could be said that removing power from the inverter under load will damage it, that might be true but better to have a damaged inverter than a damaged limb.

Unlikely to cause significant damage to your limbs due to spindle's low inertia, so personally I'd rather it damaged the limb as that'll get fixed for free on the NHS, unlike the VFD.


Why would the inverter be damaged in this situation? Is it because once the power is cut to the inverter the spindle acts as a generator and this generated current can damage the inverter?

Vaguely.


Just noticed my Huanyang vfd has terminals to add a braking resistor. If power is removed from the inverter would this still be used/effective? would it cause damage to the inverter?

If you remove the power, the inverter can't do anything as it will only remain switched on for less than 1/10th of a second before the capacitors discharge. So no, it wont apply the brake.


I would like to have a safety system that does not compromise at all on safety but has the best chance on leaving the equipment undamaged

In that case you need to separate 'fault conditions' from safety concerns - e.g hitting a limit switch or stepper driver fault signals do not pose safety hazards, so treat them as such and wire it so the machine just pauses. The only one that warrants fast and complete shutdown is pressing the e-stop, as that's what you can supposedly do if you're about to get hurt.


Now regards the Kill power or Kill signal to VFD then I used to be Kill Signal guy but I'm now I Kill all power. Reason being what happens if the signal breaks or Even the VFD goes faulty.?

The signal should be wired such that if the wire's broken or otherwise interfered with the signal changes state and the system stops. The VFD going faulty sounds exceptionally unlikely, but if you're worried about that then just have a timed relay to switch the VFD power off a couple of seconds after the signal (as mentioned earlier), since by that point the spindle will have stopped so you wont damage the VFD by cutting the power, and if it's not stopped then the VFD has gone faulty so you probably don't care about risking damage to it by cutting the power.


E-stop is hit due to Limit or some other none spindle related condition then doesn't really matter how long spindle takes to slow down and coasting to a stop isn't long or problem.

My new spindle takes 107 seconds to stop from full speed if left to coast. I tend to agree that it's not really a problem though.


*emergency stop button pressed - strategy 1 or 2

Two, see above. You could take advantage of the enable signal on the stepper drivers to disable them, then link cutting the power to the delay associated with the VFD.


I also think the braking resistor is not required because of the fairly low inertia of the load.

Yes - the internal resistor is sufficient to stop the 2.2kW spindles in less than a second, so you can easily implement the above method.

(3000th post... :moody:)

JAZZCNC
15-11-2013, 01:22 AM
I agree that for DIY either strategy is fine but maybe not everyone reading this is in a DIY situation, in which case they should be referring to the relevant regulations.
The main aim of this is to get a good emergency stop system using the gear we've got.

It would be useful if we could define some scenarios and strategies for stopping a cnc machine, your input is valuable here.

Yes Agree in industrial situation then machine needs to be safe and Regs followed to keep the HSE police happy but mostly folks here are DIY and there's world of difference between Reg compliant and being used safely in a shed.!! . . . Practical common sense is all that's needed IMO.

Regards Strategy's then here's my take.!! (which has changed over the years.! I used to kill everything regardless)

E-stop means Foooooooking Hell EVERYTHING STOP NOW.!! . . . So Strategy 1 only.!

Limit/s trip means machine is outside it's working parameters so do something about it.!! . . So disable the drives using the drives enable signal, Not killing power to drives so maintaining holding torque. At same time inform the Control software so it's halts program execution.
Send Stop signal to Spindle/VFD again leave power on has it's not an emergency, it's a machine position error so we just need it to come to a controlled stop.
Along side this you could if wanted turn off other things like vacuum etc either by informing control software or by locally controlling on/off thru Relays but all this should just be on the Limit circuit NOT The E-stop.
Same regards the Fault signals from drives, It's a machine Error not an emergency so same applies just stop the machine in a controlled manner.

If any of the above happens then it should be wired in such away that some form of Latch is dropped and not allowed to re-latch until fault is cleared and then only with Push of a Momentary button not Reset switch.

The E-stop should have ultimate control and Kill power to everything in the event of an emergency so all Latches are dropped and won't reset or start again without some input. Ie Pushing Reset momentary button.

Charge pump and over Temp etc are again machine errors not emergency conditions so just bring machine to stop in controlled manner.

Personally I wouldn't have Temperature control anything over than alert the user thru audible or Visual means. Problem comes from the manner in how the machine is stopped.? To safely stop the machine and not wreck the work piece or lose position requires a Feed hold not a Stop command.! If you stop the machine while it's moving, either thru E-stop, limit trip/machine error or just pushing Stop button on control screen then you MUST presume you have lost position thru inertia pushing, THE ONLY SAFE WAY to bring the machine to stop and not lose position is to use Feed hold and allow the control software to do a controlled stop.
Problem with this is it's doesn't do it instantly so there's always some delay until look ahead buffer is cleared or it's finished the current move. If you have an overtemp problem you won't want to wreck the job so a controlled stop is required so feed hold must be used.
It is possible to use an input and have Mach watch it then use an OEM trigger to activate the Feedhold if the state changes but personally I wouldn't and just have a Spindle siren scream at me.!!

This also answers your "Stop Button" option.! . .Pressing stop will only stop the machine and other attached devices in a semi controlled manner but it won't be controlled and can't reliably be resumed from without first homing the machine to get back into position.

Also noted you said Home limit's.? Home switches are not limits of any kind neither are they part of any system, e-stop or limit etc. They solely define the Machine coordinate Zero position and are purely input's to the Control system and nothing else..!! . . . .(Eddy I know you probably know this but others may not)

Jonathan
15-11-2013, 01:33 AM
Looks like we're all largely saying the same things now.


This also answers your "Stop Button" option.! . .Pressing stop will only stop the machine and other attached devices in a semi controlled manner but it won't be controlled and can't reliably be resumed from without first homing the machine to get back into position.

For the non-emergency stop button, you could just wire it to an input set to activate the feed hold, so the machine does in a controlled manner. It's still likely to leave a mark on the work, but prevent something worse.

JAZZCNC
15-11-2013, 01:39 AM
The VFD going faulty sounds exceptionally unlikely

Not that unlikely really has I've got one here that did just that in that it wouldn't turn off thru a signal or the control panel. Turned out to be faulty panel and was replaced by ABB but the fact was it stayed bloody on so no signal would have turned it off.!!

Jonathan
15-11-2013, 01:43 AM
Not that unlikely really has I've got one here that did just that in that it wouldn't turn off thru a signal or the control panel. Turned out to be faulty panel and was replaced by ABB but the fact was it stayed bloody on so no signal would have turned it off.!!

What's your point? The timed switch off mentioned twice (now three times) in this thread would have turned it off. Also you can't judge how likely something is with such a small sample size.

A couple of months ago I got a 15kW ABB VFD. Wired it up correctly and 5 minutes later the input rectifier blew up leaving my ears ringing for about half an hour!

JAZZCNC
15-11-2013, 01:44 AM
Looks like we're all largely saying the same things now.

Didn't see your post until after I'd posted that.



For the non-emergency stop button, you could just wire it to an input set to activate the feed hold, so the machine does in a controlled manner. It's still likely to leave a mark on the work, but prevent something worse.

Erm.!! . . . Well that would just be a Feed hold so why not Call it Feed Hold.??

JAZZCNC
15-11-2013, 01:51 AM
What's your point? The timed switch off mentioned twice (now three times) in this thread would have turned it off. Also you can't judge how likely something is with such a small sample size.

Point is that it does happen and equally you can't say it's unlikely because it has happened.!! . . . . . Agree thou it's irrelevant has it will be safe eventually if power cutoff is just delayed. ( I was more meaning it's unsafe if just relying on Signals.)

m_c
15-11-2013, 02:10 AM
E-stop systems are always a good cause for debate.
Ultimately they should stop movement likely to cause personal injury, and how that can be acheived depends on the machine.

We've got some quite expensive lorries at work with external equipment where some will kill everything including the lorry engine when an E-stop is pressed, whereas others will only kill the external equipment. There are pros and cons to both.
The key requirement is they should be fail safe, and periodically checked.

One question for everybody is, when did you last check all your limits and E-stop buttons worked?

JAZZCNC
15-11-2013, 02:30 AM
One question for everybody is, when did you last check all your limits and E-stop buttons worked?

Don't have limits but I must hit the Oh shite button at least ounce per day. . .Lol

cncJim
15-11-2013, 12:15 PM
.....
The main aim of this is to get a good emergency stop system using the gear we've got.

It would be useful if we could define some scenarios and strategies for stopping a cnc machine, your input is valuable here.

I've listed some ways to stop the machine and the strategy to adopt, I'm not saying it's comprehensive so please add or amend as you think.
.....

This is a great idea Eddy, great for noobs like me. Might be nice to add example circuits for each strategy (might be getting carried away now...:emmersed:)?
I have made some changes based on some of the feedback and tried to make clear which things should be done in hardware and software, hope that's ok. Maybe it could make a good sticky?

List of scenarios and possible strategies for dealing with them.

Scenarios


Emergency stop button pressed - Strategy 1, 2 or 2.5
Limit switch activated (not home limits) - Strategy 2 or 2.5
Spindle over temperature switch activated - Strategy 3 or 3.5
Stepper driver alarm relay activated (e.g. AM882) - Strategy 3 or 3.5
'Stop' button pressed - Strategy 4
Charge Pump error - Strategy 1, 2 or 2.5


Strategy 1


remove power to all devices immediately (Hardware)
Inform control software of Estop condition (Software)


Strategy 2


remove power to stepper drives immediately (Hardware)
remove power to ancillary devices immediately e.g. air, water, dust extraction (Hardware)
issue stop command to VFD then after delay remove power to VFD (Hardware)
Inform control software of Estop condition (Software)


Strategy 2.5


Issue stop to stepper drives then after delay remove power to stepper drives (Hardware)
issue stop command to VFD then after delay remove power to VFD (Hardware)
remove power to ancillary devices immediately e.g. air, water, dust extraction (Hardware)
Inform control software of Estop condition (Software)


Strategy 3


issue audio visual alarm before taking action (with time delay) (Hardware/Software)
After delay:-
Stopping of all machine actuators and ancillary devices (Software - "Stop" Command)
leave power supply on to VFD


Strategy 3.5


issue audio visual alarm before taking action (with time delay) (Hardware/Software)
After delay:-
inform control software to activate Feedhold (Software)
Move to safe Z (Software)
Issue stop command to spindle (Software)
leave power supply on to everything


Strategy 4


Stopping of all machine actuators and ancillary devices (Software - "Stop" Command)
leave power supply on to VFD

EddyCurrent
15-11-2013, 06:18 PM
Thanks to all who contributed it's been very rewarding I think and thanks to Dean and Jim for pointing out the FeedHold function of Mach3. With all of this each individual will have to make their own judgement, this is just mine.
After going through the available information I decided to list the 'stopping methods' for each of the major components, i.e. VFD, stepper motors, Mach3, ancillary equipment.
I decided that cutting power directly to the VFD was not for me so will implemented method 1 below.
Also I decided that control of the ancillary equipment was currently outside the scope of my control cabinet but if later on it does fall within the scope changes will have to made.


VFD stopping methods
---------------------------------
1. immediately issue 'emergency stop' command and after delay remove power to input ('e/stop' command can be set to stop drive faster than 'stop')
2. immediately issue 'stop' command and leave power to input
3. use STO function if available to prevent restart (this is not a stopping function)

Stepper Drivers stopping methods
-----------------------------------------------
4. immediately remove power to stepper drivers
5. immediately activate 'enable' signal (breakout board also uses charge pump signal to disable outputs to stepper drivers (not using 'enable' signal)

Ancillary equipment stopping methods
-----------------------------------------------------
6. immediately issue stop command (varies according to equipment)

Mach3 stopping methods
-----------------------------------
8. immediately issue Feed Hold command to Mach3
9. immediately issue Stop command to Mach3

Other stopping methods
---------------------------------
7. immediately issue audio visual signal

Next I looked at the stopping scenarios, developed strategies and assigned 'stopping methods' to them, I felt it was important to minimise the number of strategies so carried out some mental boolean algebra and Karnough mapping.

Only strategy 1 will be considered Safety related, it also aligns with the suggested drawing in Mach3 documentation.
Emergency stop is obvious, for me limit switch activation may lead to a dangerous situation, charge pump activation means Mach3 has lost control so anything could happen.


*emergency stop button pressed - strategy 1
*limit switch activated (NOT home limits) - strategy 1
*Charge Pump error - strategy 1
*'Stop' button pressed - strategy 2
*spindle over temperature switch activated - strategy 5 (assumes someone is in attendance otherwise use strategy 4)
*Stepper driver alarm relay activated (e.g. AM882) - strategy 3

Strategy 1 ( 1,4,9 )
Strategy 2 ( 2,5,9 )
Strategy 3 ( 2,4,9 )
Strategy 4 ( 2,5,8 )
Strategy 5 ( 7 )

Next up will be some updated drawings to implement this.

EddyCurrent
15-11-2013, 11:16 PM
In the interest of practicality I'm proposing these changes

*emergency stop button pressed - strategy 1
*limit switch activated (NOT home limits) - strategy 1
*Charge Pump error - strategy 1
*'Stop' button pressed - strategy 2 or strategy 4
*spindle over temperature switch activated - strategy 5
*Stepper driver alarm relay activated (e.g. AM882) - strategy 2

The reasons being,
* If the spindle is overtemp then sound an alarm and let the operator take action at the Mach3 screen or otherwise.
* If the stepper driver alarm relay operates then it should be sufficient to issue the 'enable' signal, if not then the emergency stop can be operated.

finding a suitable off delay for the VFD contactor AT THE RIGHT PRICE is proving a challenge right now. There are some cheap ON delays which could be used but would not be fail safe.

EddyCurrent
16-11-2013, 06:10 PM
This seems to be the document required, have not read it yet but the title is "Application Note
Interfacing AC Drives with Safety Relays"

http://www.ab.com/support/abdrives/powerflex70/Interfacing_Safety_Relays_Rev04.pdf


Also a section in this

http://www.bara.org.uk/info/safety/A_Practical_Guide_to_Machine_Safety_Application.pd f

Boyan Silyavski
16-11-2013, 06:40 PM
Kill all power, no doubt.

Here is how i have my CNC working:

-the PC id surge protected and connected to a 1500w UPS. Also the CNC is conected there
-the VFD enables the BOB
-the charge pump enables the BOB and the VFD

Typical everyday scenarios:

Power interruption from outside of the house. It happens a lot here in Spain. Or a fuse trip. I have a lot of stuff at that fuse :-)
-the VFD stops and stops Mach3. I go and see which line the process is. I write it down on a piece of paper. If power comes for the next half hour , i just continue from there. If not, i stop the PC and when i have power again, simp[ly continue from the line.

My mistake
-Spindle digs, VFD trips, Mach3 stops, Usually reset, lift the Spindle, check Z0, usually that is the mistake, Z0 and voilaaa

Mach3 goes down and decides some crazy movement. Happens rarely but happens.
-the bit digs, spindle stops and trip signal stops the process. if nothing is damaged, i check the xyz0 and if ok i continue from there, if not, i throw in the garbage and do it again

PC stops, restarts alone or whatever similar.
-VFD stops

I hit the EStop
-no power to the drives, no power to the BOB, VFD stops

I greatly recommend a pause button also on the machine. Sometimes when not sure what is happening if nothing crashes is better to just pause the process and contemplate. Though an extra second is lost meanwhile

EddyCurrent
16-11-2013, 07:52 PM
I greatly recommend a pause button also on the machine. Sometimes when not sure what is happening if nothing crashes is better to just pause the process and contemplate. Though an extra second is lost meanwhile

What would you have it do ?

Stop the VFD
Send a FeedHold signal to Mach3 and let it control the stepper motors


Is it not just as easy to do it from the PC ?

Boyan Silyavski
16-11-2013, 08:31 PM
What would you have it do ?

Stop the VFD
Send a FeedHold signal to Mach3 and let it control the stepper motors


Is it not just as easy to do it from the PC ?

Sometimes i am not sure what happens, so i just hit the pause / feedhold/ button, instead of the estop. Spindle still rotates and i check. if everything ok, i hit the "cycle start" button which is also at the machine, so everything continues, as if nothing have happened.
The keyboard is 2m away in my case, so its not easier.

I do this if i want to check if the material has loosened on the fixture, clean some bearings, remove sticks from the vacuum shoe and so, without further interrupting the process.

On next machine i will have flood and vacuum buttons also. Sometimes when i want to do something with the keyboard i accidentally touch the wrong buttons. last time somehow i zeroed the machine coordinates. So had to stop, go to home, zero again, get out of Mach3,save fixture, then again in, zero on the work piece and start again the job.

cncJim
17-11-2013, 09:38 PM
finding a suitable off delay for the VFD contactor AT THE RIGHT PRICE is proving a challenge right now. There are some cheap ON delays which could be used but would not be fail safe.


This seems to be the document required, have not read it yet but the title is "Application Note
Interfacing AC Drives with Safety Relays"

http://www.ab.com/support/abdrives/powerflex70/Interfacing_Safety_Relays_Rev04.pdf


Excellent doc eddy, spot on. Also very handy as it details hooking up a AB msr138dp which I have just bought on ebay for 30! After looking into the specs there are 10 different varieties (various voltages/delay ranges) and I think this is the right one/most useful (hope so, I've bought it now!) - 440R-M23143 (24v - 0.15 - 3 seconds delay)?

Also, I spoke to the guy and he said he has another which he is willing to sell for the same price. Let me know if you are interested eddy and I will pass on his number

Cheers.

Boyan Silyavski
17-11-2013, 10:27 PM
Eddy,
what is this one: *spindle over temperature switch activated ?

Where did you find a cheap temperature sensor with digital display that has a contactor or signal at programmed temperature?

I have bought a cheap 7eur battery one with temperature alarm, and thought of using the alarm output ~3v to connect to the BOB, but forgot about this project.

Once i accidentally switched off the water pump and spindle worked all day before i touched it and saw it was hot. Nothing happened. Still works. Though was just V carving.

EddyCurrent
17-11-2013, 10:59 PM
Good timing lads !

@silyavski, the temperature switch was already built into my spindle, it is closed normally and opens at high temperature.
@cncJim, see latest drawings

Here are my latest drawings

10806108071080810809

Features
---------
Strategy 1

* Emergency stop immediately signals VFD to stop and several seconds later (time to be assessed but possibly 6 seconds) delayed contacts of Guardmaster safety relay open to operate STO (Safe Torque Off) feature of VFD which disables control voltage and power semiconductors.
* Power removed from Stepper Drivers via Guardmaster safety relay and K1
* Stop command issued to Mach3 via K1 (even if Mach was still active the VFD and Stepper Drivers would still be disabled)

Strategy 2

* Stop signal sent to VFD via K3 relay
* Stop command issued to Mach3 via K3
* Enable (ENA) signal activated via Mach3 and BOB to disable stepper drivers

Strategy 3

Not implemented - same as Strategy 2

Strategy 4

* Stop signal sent to VFD via K4 relay
* FeedHold command issued to Mach3 via K4
* Enable (ENA) signal activated via Mach3 and BOB to disable stepper drivers

Strategy 5

Not implemented


Notes:

Strategy 3 could be implemented by incorporating a relay contact from K3 into K1 coil circuit however because all 4 contacts of K3 are being used another single contact relay would have to be connected in parallel with K3.
Strategy 5 could be implemented by removing the Pause push button and having only K4-4 contacts operational.

* A PAUSE push button has been added, this will stop the VFD and send a FeedHold signal to Mach3, to continue the ON (RESET) push button is pressed.
* A Charge Pump relay has been added to the Emergency Stop circuit this so the system can initiate an Emergency Stop if the software stops or communication is lost.
* If the Circuit Breaker for the Stepper Drivers trips then K1 will de-energise and send a STOP signal to Mach3.
* ENA signal now connected from BOB to all Stepper Drivers

( ** As yet I have not cobbled together the Charge Pump relay but I think a small 5v coil one will do the job as my BOB can source 20mA. **)

Relays K2,K3 and K4 are these
http://www.ebay.co.uk/itm/1set-Base-OMRON-coil-power-relay-14pin-4NO-4NC-MY4NJ-MY4N-J-5A-DC24V-4PDT-/400380624260?pt=LH_DefaultDomain_3&hash=item5d388b7d84

EddyCurrent
18-11-2013, 10:37 PM
I'm thinking this is going to be my Charge Pump relay circuit. My BOB ENA signal is active low so the relay will be in the 'healthy' state when de-energised, this is not fail safe and I could have inverted the signal but it's going to do. The BOB is supplied by 24vdc and so GND is common to the 5v and the 24V.

10822

irving2008
18-11-2013, 11:46 PM
I'm thinking this is going to be my Charge Pump relay circuit. My BOB ENA signal is active low so the relay will be in the 'healthy' state when de-energised, this is not fail safe and I could have inverted the signal but it's going to do. The BOB is supplied by 24vdc and so GND is common to the 5v and the 24V.

10822

You have C and E swapped over. Its an NPN so E is always to -ve rail.

with only 3 or 4 more components you could make it failsafe and i would...

EddyCurrent
19-11-2013, 12:01 AM
Irving, you are right, I just threw the drawing together on Paint and I have indeed got e and c crossed over. What would your plan be to make it failsafe ?

Maybe this ? (sorry for poor drawing, no tools at hand on this pc)

10832

cncJim
19-11-2013, 12:24 PM
Good timing lads !

...

( ** As yet I have not cobbled together the Charge Pump relay but I think a small 5v coil one will do the job as my BOB can source 20mA. **)



Good stuff EddyCurrent, I'm still working my way through your diagrams trying to fully understand :) - Do you have any provision for activating your estop circuit from the controlling software? I suppose the argument could be made that its not needed unless the pc a distance from the machine?



Relays K2,K3 and K4 are these
1set Base+OMRON coil power relay 14pin 4NO 4NC MY4NJ MY4N-J 5A DC24V 4PDT | eBay (http://www.ebay.co.uk/itm/1set-Base-OMRON-coil-power-relay-14pin-4NO-4NC-MY4NJ-MY4N-J-5A-DC24V-4PDT-/400380624260?pt=LH_DefaultDomain_3&hash=item5d388b7d84)
I have just acquired 10 of these from a control panel I stripped down (7x 24v and 3x 230v) which seem to be a similar spec to yours:-
10833
Finder TYPE 55.34
The 5A rating, is that for the entire relay or for each contact?

There are also 4 contactors which I haven't taken out yet. Are there any practical/safety differences between a relay and a contactor?

irving2008
19-11-2013, 12:40 PM
Irving, you are right, I just threw the drawing together on Paint and I have indeed got e and c crossed over. What would your plan be to make it failsafe ?

Maybe this ? (sorry for poor drawing, no tools at hand on this pc)

10832

that'll do it. i'd put a series resistor between BOB and base of transistor, value depends on pull-up on BOB. If there is no pull-up (i.e. its an o/c output) use 10k to 5v rail.

R needs to be something like 2k7 0.5W rating if connected to 24v, or 470R 0.125W if connected to 5v rail.

BD679 is fine as output transistor if a bit of an overkill. Any small signal NPN with a gain >50, Vce >40v and Ic >200mA will do for the input transistor e.g 2N3904, BC337 or similar

Jonathan
19-11-2013, 01:02 PM
If the breakout board output is open collector, why not reduce the component count by using a PNP transistor to invert the signal?

e.g:
10834

Edit: Also don't forget the back-emf protection diode!

cncJim
19-11-2013, 01:11 PM
I'm thinking this is going to be my Charge Pump relay circuit. My BOB ENA signal is active low so the relay will be in the 'healthy' state when de-energised, this is not fail safe and I could have inverted the signal but it's going to do. The BOB is supplied by 24vdc and so GND is common to the 5v and the 24V.

10822


Irving, you are right, I just threw the drawing together on Paint and I have indeed got e and c crossed over. What would your plan be to make it failsafe ?

Maybe this ? (sorry for poor drawing, no tools at hand on this pc)

10832


that'll do it. i'd put a series resistor between BOB and base of transistor, value depends on pull-up on BOB. If there is no pull-up (i.e. its an o/c output) use 10k to 5v rail.

R needs to be something like 2k7 0.5W rating if connected to 24v, or 470R 0.125W if connected to 5v rail.

BD679 is fine as output transistor if a bit of an overkill. Any small signal NPN with a gain >50, Vce >40v and Ic >200mA will do for the input transistor e.g 2N3904, BC337 or similar

R needse 2k7 0.5W rating if connected to 24v, or 470R 0.125W if connected to 5v rail.

BD679 is fine as output transistor if a bit of an overkill. Any small signal NPN with a gain >50, Vce >40v and Ic >200mA will do for the input transistor e.g 2N3904, BC337 or similar

Please forgive my ignorance but could someone explain how this will work in basic terms? Why is Eddy's first circuit not fail safe and how does the next circuit achieve that?

Sorry, I've not had a lot of sleep over the past few nights (babies all have colds....) and I think my brain may be turning to mush.

Jonathan
19-11-2013, 01:16 PM
Please forgive my ignorance but could someone explain how this will work in basic terms? Why is Eddy's first circuit not fail safe and how does the next circuit achieve that?

The transistor is used as a switch. When positive current is applied to the base of an NPN it switches on. In the original circuit, the transistor is simply connected in series with the relay, so when the current is applied the transistor switches on and so does the relay. The problem is, if the signal to the base is broken (e.g. wire accidently cut), the transistor and thus the relay will switch on. We want the relay to be off in this situation, so another transistor is used to invert the signal. When the current is applied to 'new' transistor, it switches on so connects the base of the second transistor to ground, which in turn switches it off - hence the signal is inverted.

cncJim
19-11-2013, 06:37 PM
The transistor is used as a switch. When positive current is applied to the base of an NPN it switches on. In the original circuit, the transistor is simply connected in series with the relay, so when the current is applied the transistor switches on and so does the relay. The problem is, if the signal to the base is broken (e.g. wire accidently cut), the transistor and thus the relay will switch on. We want the relay to be off in this situation, so another transistor is used to invert the signal. When the current is applied to 'new' transistor, it switches on so connects the base of the second transistor to ground, which in turn switches it off - hence the signal is inverted.

Thanks for taking the time to reply Jonathan. Very helpful. I was also having hard time understanding/visualising the "active low" part of the puzzle.

This also helped me understand:-
10837
"If the input signal is high there will flow current through R2 and the transistor's base-emitter junction (base, not gate). This current will be amplified, and the collector current through R1 will cause a voltage drop so that the output will be low. Input high, output low.
If the input signal is low there won't be any base current, and no collector current. No current through R1 means no voltage drop, so that the output will be at +V. Input low, output high."

EddyCurrent
19-11-2013, 09:38 PM
Good stuff EddyCurrent, I'm still working my way through your diagrams trying to fully understand :) - Do you have any provision for activating your estop circuit from the controlling software? I suppose the argument could be made that its not needed unless the pc a distance from the machine?

Yes that's what the Charge Pump relay is doing. The BOB is turning a 12khz signal from Mach3 into a 0 or 5vdc output, on my particular BOB the output of ENA is 0v when Mach3 is healthy and +5v dc when it stops.


I have just acquired 10 of these from a control panel I stripped down (7x 24v and 3x 230v) which seem to be a similar spec to yours:-
10833
Finder TYPE 55.34
The 5A rating, is that for the entire relay or for each contact?

Those look just right, I looked on Farnell and they appear to be 4 pole Change Over which is what you need if using my diagram, the 5A rating is for each contact.

EddyCurrent
19-11-2013, 09:42 PM
BD679 is fine as output transistor if a bit of an overkill.

Thank's for info on component sizes.
That is correct, it's just that I have some and they have a high gain because I need to keep the load on ENA as low as possible as it's also supplying 4 x stepper drivers.

cncJim
19-11-2013, 09:56 PM
Yes that's what the Charge Pump relay is doing. The BOB is turning a 12khz signal from Mach3 into a 0 or 5vdc output, on my particular BOB the output of ENA is 0v when Mach3 is healthy and +5v dc when it stops.


Of course, what a spanner! sorry that makes perfect sense now.

EddyCurrent
19-11-2013, 10:02 PM
If the breakout board output is open collector, why not reduce the component count by using a PNP transistor to invert the signal?

e.g:
10834

Edit: Also don't forget the back-emf protection diode!

That would be a sensible solution Jonathan and one that I shall test, thank you

EddyCurrent
19-11-2013, 10:09 PM
The breakout board I'm using is this one SYSTEM1 (http://www.diycnc.co.uk/html/system1.html)
I emailed Roy regarding the charge pump relay and he obviously suggested a transistor buffer but more interestingly the board has 'spare' 12v and 5v outputs and his suggestion was to connect a small 5v reed type relay between +5v and ENA. This has the advantage that when Mach3 is healthy ENA is at 0v therefore a potential of 5v exists between +5v and ENA making it fail safe plus it would share the load better with the 4 connected AM882's. This might be the way to go other than the reed relay does not sound too appealing although in practice one of those encapsulated type that look like a chip with about 8 legs have proved to be reliable in industrial situations.

EddyCurrent
19-11-2013, 11:27 PM
There are also 4 contactors which I haven't taken out yet. Are there any practical/safety differences between a relay and a contactor?

With electrical systems there are generally two main circuits, the 'control circuit' and the 'power circuit'. Contactors are regarded as components of the power circuit whereas relays belong to the control circuit, it's mostly to do with the current carrying capacity and the ability to break that circuit without arcing or at least controlling the arcing. There are relays with positive guided contacts and these are for use in safety circuits, I have not come across equivalent contactors but that's not to say they don't exist. I'm not 100% on this but I think relays originated in communications areas such as telephone exchanges. Contactors can have auxilliary contacts fitted which in essence are relay equivalents and are used in the control circuits for those contactors.

irving2008
19-11-2013, 11:35 PM
Just to clarify Jonathan's answer, the BOB ENable signal is Active Low i.e. enabled = 0v, disabled = 5v. In Eddy's original circuit the relay would be OFF when the BOB says Enabled and ON when disabled. But a BOB failure, a supply voltage failure, or burn out of the transistor would all turn the relay OFF, an enabled state, so not fail safe. As J says, the addition of the second transistor inverts the logic so relay is ON only when system is enabled and voltages are present.

J's later solution achieves the same result by using a PNP transistor to invert the logic.

[edit] typed this ages ago but forgot to hit submit.... :roll: and now its out of date lol



The transistor is used as a switch. When positive current is applied to the base of an NPN it switches on. In the original circuit, the transistor is simply connected in series with the relay, so when the current is applied the transistor switches on and so does the relay. The problem is, if the signal to the base is broken (e.g. wire accidently cut), the transistor and thus the relay will switch on. We want the relay to be off in this situation, so another transistor is used to invert the signal. When the current is applied to 'new' transistor, it switches on so connects the base of the second transistor to ground, which in turn switches it off - hence the signal is inverted.

irving2008
19-11-2013, 11:51 PM
That would be a sensible solution Jonathan and one that I shall test, thank you

Be very, very sure the BOB output is truely open collector if Vs = 24v or at best it won't work (I'll leave it to the reader to explain why :) ) and at worst you could fry the BOB!

Alternatively make Vs = 5v

Rb for Vs = 5v is 1k
Rb for Vs = 24v is 4k7

1/4w resistors will be fine

m_c
20-11-2013, 12:01 AM
Anything that switches arcs.
Technically a contactor is just another name for a relay, however the term contactor has been adopted to describe a specific type of relay.

Contactors main benefit is they can handle far higher currents, and normally have a pretty large airgap to ensure a well isolated disconnection. There's no real reason to use a contactor unless the application dictates it, especially if you can get away with a far cheaper relay.
I'm pretty sure you can get contactor set-ups that will detect a welded contact, which essentially gives you the equivalent of a positive guided relay. All you need to do with a contactor is monitor the contact plate travel, so it's just a case of actuating a suitable switch to detect that it's not returned fully. However if you've just welded a contactor shut, then there's a major design flaw somewhere!

cncJim
20-11-2013, 03:01 PM
Thanks for the info m_c!

So am I missing something?? (more than likely!) - We have a fail safe safety relay which will be switching non-fail safe relays? (I'm thinking its possible for a contact to weld?)

Isn't this kinda defeating the purpose?

Apologies if I have miss-read your circuit diagram EddyCurrent.

m_c
20-11-2013, 05:15 PM
The key to your answer lies in the fact you have a single relay controlling several others. If one of the several fails, chances are it's not going to cause a major issue as everything else will still stop, but if the single one fails it's more likely to cause major issues.

However a correctly designed system, the relays should be suitably sized that contact welding is not an issue, and suitably fused. Safety relays aren't entirely fail safe, they've just got extra contacts so you can check to see if they're working correctly.

It's all a case of risk management and cost.
Ideally safety systems should be tested reguarly, to ensure they are functioning as designed, and any problems found before they cause problems in the case of an emergency.
However, if you have something that needs to run 24/7, or where regular testing could be a problem, then you want to minimise the amount of testing that needs done, and look at using more failsafe methods.

In the context of a homebrew machine running Mach/Linux, you want a couple things to happen during an e-stop. First you want to cut power, and second you want to the tell the computer things have stopped. Should the power fail to cut, then the computer should still know things have gone wrong and stop generating pulses. That way should the main power not die, the computer should still stop commanding any movement. Plus you always have the completely failsafe method of unplugging it.

Industrial machinery does get a bit more involved, but there are no hard and fast rules on implementation, just that things should stop in a controlled and quick manner. There are stipulations on time taken to stop things like exposed cutters, but there is no requirement for power to be cut, just for movement to stop. However generally anything that can be stopped faster under power, will use a time delay system, which when activated, will issue a stop command, then after a short delay, cut power.

One thing to remember, nothing electrical is ever truly failsafe, and is why you should still be able to manually kill all power should things go totally wrong.

EddyCurrent
20-11-2013, 10:49 PM
@cncJim more reading regarding the 4 safety categories, once the risk assessment identifies the required safety category only then can the correct hardware be selected.

http://www05.abb.com/global/scot/scot209.nsf/veritydisplay/b98cfaed98af7397c12573ad00471f6a/$File/2CDC110004C0205_03.pdf

It's correct when m_c says the components are selected to minimise faults such as contact welding, also if a failure does occur then a restart should not be possible. For example if a contactor was used to remove power form the VFD then it should have a normally closed auxilliary contact in series with the safety relay reset button to ensure the contactor is de-energised or not stuck closed by contact welding and I could do that with my K1 for the stepper driver power.
As I said in a earlier post the drawings I have put on here are for my machine and anyone else needs to carry out their own risk assessment for their machine. At the end of the day as JAZZCNC pointed out none of this is strictly required for a DIY machine for use at home because the legislation does not apply to domestic situations but my theory is that for the little extra involved we might as well go the extra mile and make it as good as it needs to be. Because the VFD I'm using has the STO feature means I have decided not to use a contactor to cut power once the safety relay times out, if it did not have this feature then I would have used a contactor.
So the correct procedure is to risk assess the machine to identify the required safety category then design the safety system to meet that category both by choice of appropriate components and how those components are connected together.
I would be very surprised if the type of breakout boards we are using would meet the requirements of a safety system but this is the only means of telling the computer that things have stopped (as far as I know) but if other things come into play first such as cutting power to moving parts or making moving parts safe then it might not matter what the computer is trying to do as it's commands are falling on deaf ears so to speak.
Plus I realise all this procrastination on my part is just putting off the mechanical build part of my project :shame:

EddyCurrent
24-11-2013, 12:01 PM
Drawing updated, (added a link missing on E/Stop relay, added K1 feedback contact and E/Stop relay N/C contacts into RESET circuit). This will be the last update of drawings until the project is finished and I shall post the 'as built' version.
10857
Instead on implementing a load more buttons on the panel itself I'm thinking about getting one of these,
Cheap High quality 2.4G CNC 3 axis/ 4 axis Mach3 wireless Handle Wheel, Mach3 engraving machine, LCD, cnc wireless channel-in Woodworking Machinery Parts from Industry & Business on Aliexpress.com (http://www.aliexpress.com/item/cheap-2-4G-CNC-3-axis-Mach3-wireless-Handle-Wheel-reciever-for-Mach3-engraving-machine-LCD/648918419.html)
I was going to get the cheaper version, wired and without a jog wheel but it didn't have a pause function (though it might have programmable ?) but for the little extra cash this seems to have it all and it's wireless.
USB should not be an issue because I'm using an Ethernet Smooth Stepper.

Boyan Silyavski
28-11-2013, 06:01 AM
Arent these 2 (http://www.cnc4pc.com/Store/osc/index.php?cPath=23) similar to what you have been trying to do? the secon one usualy is already integrated in your BOB.

EddyCurrent
28-11-2013, 09:01 AM
Thanks silyavski they look good products, the truth is because I knew nothing regarding cnc at the start I did not research enough products before deciding what to buy. If I was starting again it would probably be a bit different.
I have however reached a point where I am happy with how it is going.

EddyCurrent
13-12-2013, 01:24 PM
One problem with not creating a proper specification is that you don't know when the job is finished, however I'm sure I've dicked about with this panel far too long so I'm saying this is the 'as built' version.
I started a thread about using VBscript but was directed by Jazzcnc to look at Brains so I did and was pleased with the results.
Mach3 Brains have been used for the control panel pushbuttons and the control panel red led for alarm indication.
I used 'output 1' from Mach3 which is configured to 'pin 14' of the breakout board and constructed a relay using one 2k2 resistor in series with the base of a BD679 (overkill but I already had some). The Mach3 Brain logic then controls output to this solid state relay which in turn controls the red led.
I also revisited the Emergency stop circuit and the Stop / Pause ' Reset functions, they now operate as described below.
Attached are the schematics and in the Zip file are the Mach3 Brains for pushbuttons and alarm indication also a spreadsheet showing the logic used.

Emergency Stop circuit
consists of 2 emergency stop buttons, one machine mounted, one control panel mounted, machine limit switches, VFD fault relay.
Upon activation of the E/stop;
1. The VFD uses special emergency stop ramp (faster than normal stop ramp) and after 6 seconds it's STO function is activated via the PILZ relay and K5
2. K1 is de-energised removing power to the AM882 drivers
3. E/Stop signal sent to Mach3, charge pump stops and breakout board uses 'enable' output to disable all outputs to AM882's and spindle.

'Stop'
Stops operation of machine by de-energising K3, sending Mach3 a 'stop' signal, also stops the VFD by removing the RUN signal.
Can be activated by;
1. using control panel red push button
2. any AM882 going into alarm

'Pause'
Pauses operation by de-energising K4, sending a 'FeedHold' signal to Mach3
can be activated by;
1. using control panel blue push button
2. spindle over temperature switch.
3. Any AM882 going into alarm will de-energise K4 because it's going to stop the machine in any case. The Mach3 Brain uses K3,K4 logic for alarm indication.
If the spindle is required to keep turning then a link can be connected as shown in the schematic diagram.

'Reset'
Resets the PILZ emergency stop relay also K3 and K4 via green push button.
1. If the machine has just been switched on the green pushbutton will reset the PILZ relay and K3, K4, sends Mach3 a 'reset' signal
2. If the machine has been 'paused' the green push button will reset K4 and send Mach3 a 'Cycle Start' signal.
3. If the machine has been 'stopped' the green push button will reset K3 and wait for user intervention to restart via Mach3 screen.


green led (power on)
indicates the PILZ emergency stop relay is energised

red led (alarm/fault)
provides indication by means of flashing at different rates for;

E/Stop was pressed
'Stop' initiated from Mach3
'FeedHold' initiated from Mach3
'Stop' initiated from Control Panel
'FeedHold' initiated from Control Panel
AM882 Driver in fault

10981109821098310984

JAZZCNC
13-12-2013, 07:40 PM
It's looking good Eddy and Massive OTT for DIY thou I'm struggling to find a Limit override.? . . . You'll need this to back off the Limits when tripped.!

EddyCurrent
13-12-2013, 09:28 PM
It's looking good Eddy and Massive OTT for DIY thou I'm struggling to find a Limit override.? . . . You'll need this to back off the Limits when tripped.!

Thanks but surely it's not massively OTT ?. Regarding limits, it's not going to hit the limits :yahoo:

JAZZCNC
13-12-2013, 09:41 PM
Thanks but surely it's not massively OTT ?.

IMO and in industry No but Compared to most DIY builds then yes it is OTT.!!. . . . . .Find me another build that's using Brains Etc to watch inputs.? Most don't even have or know what a brain is let alone how to make one control anything..Lol


Regarding limits, it's not going to hit the limits :yahoo:

If small machine I'll give you 2 days Max before you trip a limit. .. Lol

EddyCurrent
18-12-2013, 10:34 PM
Got most of the frame tacked up this week just using small stick welder ready for MIG welding ASAP.
It's taken 18 metres of 50x50 box section and about 5m of 100x50 box, plus some 50x10 and 30x6 flat bar, the wife is going to struggle getting into the van.
Pictures to follow shortly I hope.
It also confirmed something I already knew and that is, the only metal I like playing with is when it's coming through my headphones 11041

EddyCurrent
19-12-2013, 06:53 PM
The frame so far, don't be zooming in on the bird shite welds, it's holding together fine until I get it to the MIG welder.
Only bits missing are the two top 100x50 box sections that will carry the rails, these bolt onto the 8 pieces of flat plate and hence adjustable.
You can see my vast work area, also pic of the spindle.

110431104411045

GTJim
20-12-2013, 12:24 PM
That is looking like one very sturdy frame. Very nice

mekanik
20-12-2013, 01:02 PM
Very nice Eddy

Wobblycogs
20-12-2013, 02:34 PM
I agree, that is a very nice looking frame, in fact this is turning out to be one of the best build threads. The earlier posts discussing the electrical side of the build have been really useful and a great inspiration for my build. I've ordered a lot of my parts from Chalcon as well (good find), I'm just waiting for a larger case as the one I ordered initially was a bit on the small side.

JAZZCNC
22-12-2013, 04:32 PM
Missed this.! . . Coming on nice Eddy. .:encouragement:

njhussey
23-12-2013, 05:27 PM
Looking good Eddy!! This is inspiring me to pull my finger out and get on with my build. I've not done any electrical bits or welding now for weeks as I just don't seem to have the time either at work in breaks or at home :dejection:

EddyCurrent
31-12-2013, 10:15 PM
You might have read in another thread that I'm having trouble getting my spindle running in Vector Speed mode, I've tried everything so have had to finally contact ABB.
Also I got the frame moved out of garage to workshop and it reminds me of the time we bought a three seater reclining sofa, it looked just right in the showroom but when we got it home it was as big as a tank so back it went !. Anyway it means I need some structural alteration so I've got the lintels (it's a double skin block wall with cavity) and intend cutting a doorway from the workshop through into the adjoining wood store. This will be 're-purposed', as they say, into a 'consumables and wood' store which will allow a reshuffle of machinery and hence space for the cnc router. It all sounds very grand but the consumables and wood store will only be about 3m x 1.4m

JAZZCNC
31-12-2013, 11:03 PM
You might have read in another thread that I'm having trouble getting my spindle running in Vector Speed mode, I've tried everything so have had to finally contact ABB.


So what was the outcome.?

EddyCurrent
31-12-2013, 11:24 PM
They told me to do what I'd already tried so I've sent more info on parameters and spindle motor data, don't expect a reply for a few days but you never know.

EddyCurrent
27-01-2014, 11:33 PM
At last, structural alterations finished to workshop, what a damn mess it makes cutting a doorway through double skin concrete blocks. I've also rearranged the shed layout and there's room for everything now.
Frame now painted and rail bearing beams mounted. The shims worked okay but if you imagine the Forth Rail Bridge it's a bit like that where the 'humps' are in the gaps between the bolted flanges. Of course when I say humps I'm talking about 0.2mm. Now that's not so bad, but, and it's been said before by others, looking at the ends of the beams they are leaning very slightly out which means the rails and hence linear bearings are also going to lean out. To get things moving I have therefore decided to epoxy the top surface and to just for diversity (and cost) can anyone see a product here Polyester - Standard, Silicone Rubber items in MB-Fibreglass store on eBay! (http://stores.ebay.co.uk/mb-fibreglass/) that might fit the bill, I think I need 2 to 3mm max thickness.

Also more news on the issue with ABB drive + Elte spindle, soon.

njhussey
27-01-2014, 11:52 PM
Now that's not so bad, but, and it's been said before by others, looking at the ends of the beams they are leaning very slightly out which means the rails and hence linear bearings are also going to lean out.

Sounds like a persuader is called for...and if the small one doesn't work then get the big one out :)

Boyan Silyavski
28-01-2014, 01:40 AM
... To get things moving I have therefore decided to epoxy the top surface and to just for diversity (and cost) can anyone see a product here Polyester - Standard, Silicone Rubber items in MB-Fibreglass store on eBay! (http://stores.ebay.co.uk/mb-fibreglass/) that might fit the bill, I think I need 2 to 3mm max thickness.

Also more news on the issue with ABB drive + Elte spindle, soon.

Eddy,why experiment if you know what works for sure? West System Epoxy 105/209.

EddyCurrent
28-01-2014, 09:53 AM
Sounds like a persuader is called for...and if the small one doesn't work then get the big one out :)

That only works for fitters so I'm thinking about wedging a few screwdrivers in :glee:

EddyCurrent
28-01-2014, 09:55 AM
Eddy,why experiment if you know what works for sure? West System Epoxy 105/209.

I know but it's one of those times when I feel an equivalent can be found at much lower cost, I'll think about it today.

njhussey
28-01-2014, 10:15 AM
I know but it's one of those times when I feel an equivalent can be found at much lower cost, I'll think about it today.

I'll be looking with interest then.....:biggrin:

EddyCurrent
28-01-2014, 11:57 AM
What about this ?

Epoxy Resin ideal for fibreglass repair and general use (http://www.resinstore.com/epoxy-packs.html)
Syntac EPAFD Slow Cure Epoxy Resin Pack

Wobblycogs
28-01-2014, 12:18 PM
In terms of pot time it looks fine but it doesn't mention anything about the viscosity of the mix. My guess is that the viscosity would be ok but do you really want to risk it for about 20? We know from others experience that West System is almost like water when mixed and will self level in the time it takes to set. Last thing you want is to mix up a big batch of this stuff, pour it on and then watch at it slowly sets with a dirty great lump where you poured it in. Other than that I'd say go for it, I'd certainly be very interested to see if there was a cheaper alternative.

As a side note, if you don't have them a cheap set of scales is well worth it, the density of the two components is different enough that by volume measurements won't cut it (unless you are going to do the calculation to figure out the correct volumes of course).

njhussey
28-01-2014, 12:26 PM
It does say low viscosity, but as you say is it really worth it? Does look like it'll fit the bill mind! I'm just drawing fences on my frame to see what volume I'll need...I've emailed them to see if it's equivalent to the Wests System!

njhussey
28-01-2014, 01:46 PM
Oh feck it....rush of blood to the head.....should have some winging it's way to me shortly. 33.36 inc P&P for 1.5kg of resin and 0.5kg of slow cure hardner. Will have a play and let you know how it pours. I reckon that I'll need 0.63 litres of mixed epoxy for 5mm depth so the standard pack should do nicely!

EddyCurrent
28-01-2014, 04:38 PM
Now I feel responsible if it's shit so I'll have to order some as well 11391
I was going to anyway, I like to live on the edge sometimes :glee:

Anyway just compared viscosity, West = 650 cps, Syntac 650-750 mPas, (1 cps = 1 mPas)

I'm thinking the main thing here with both of them is to get a good temperature going before pouring, it needs to be string vest only temperature minimum in the shed.

http://www.westsystem.com/ss/assets/Product-Data-PDFs/TDS%20105_209.pdf
http://www.reactiveresins.com/syntacliquidepoxyresins.pdf

njhussey
28-01-2014, 04:48 PM
Now I feel responsible if it's shit so I'll have to order some as well 11391
I was going to anyway, I like to live on the edge sometimes :glee:

Anyway just compared viscosity, West = 650 cps, Syntac 650-750 mPas, (1 cps = 1 mPas)

I'm thinking the main thing here with both of them is to get a good temperature going before pouring, it needs to be string vest only temperature minimum in the shed.

http://www.westsystem.com/ss/assets/Product-Data-PDFs/TDS%20105_209.pdf
http://www.reactiveresins.com/syntacliquidepoxyresins.pdf

Don't worry about it Eddy...I compared and they looked pretty identical...so in a rush of blood to the head bought some. You'll probably be using it before I do anyway as I've got 44 x M5 holes to drill and tap for the rails and before I can do that I've got to make a plate so I can get the linear carriages mounted to get the rails in the correct position on the box section. At the rate I'm going at the moment it will be summer by the time I've done that :hopelessness:

Wobblycogs
28-01-2014, 05:21 PM
It's interesting you say you'll make it hot in the shed as I was just wondering whether it would be better to make the environment warmer or cooler. The mixture will certainly start of with a lower viscosity if it's warmer but it will also set faster as well (a rule of thumb from chemistry is a reaction will go twice as fast for every 10 deg C warmer) which means there is less time for it to find a level everywhere. I can't help feeling you'd be better off working with it as cold as you can to give it time to spread out before it sets. It says it'll cure down to 8 deg C if you are willing to accept a reduction in mechanical strength. Might be worth an experiment, make up a small amount cold and pour it onto a piece of scrap, see how far it spreads then repeat with a warm batch / environment.

njhussey
28-01-2014, 05:38 PM
It's interesting you say you'll make it hot in the shed as I was just wondering whether it would be better to make the environment warmer or cooler. The mixture will certainly start of with a lower viscosity if it's warmer but it will also set faster as well (a rule of thumb from chemistry is a reaction will go twice as fast for every 10 deg C warmer) which means there is less time for it to find a level everywhere.
See the Chemistry did come in useful!!


I can't help feeling you'd be better off working with it as cold as you can to give it time to spread out before it sets. It says it'll cure down to 8 deg C if you are willing to accept a reduction in mechanical strength.

My shed will be ideal then as it's bl***y freezing in there at the moment!!!
I'll do mine in the test bay at work, there's one bay used for storage that's colder than the rest but still above 10C I'd guess.


Might be worth an experiment, make up a small amount cold and pour it onto a piece of scrap, see how far it spreads then repeat with a warm batch / environment.

I'll be doing that for sure before committing to the real thing. I wonder if you can gradually increase the ambient temperature once it's had 12 hours or so to find the level so that you get the best of both worlds?!

EddyCurrent
28-01-2014, 05:48 PM
It's just that the West data sheet says this;

Minimum recommended temperature 70F (21C)
*Epoxy cures faster at higher temperatures and in thicker applications

and the Syntac data sheet quotes the viscosity at 25 deg.C

Clive S
28-01-2014, 05:50 PM
I think you should be careful re the temperature read the link to the wests system and it shows that it must not be cold, also I would check with your supply what the shrinkage and compression strength is of their product as there is not a lot of info on their data sheet. Don't forget to seal the inside of the trough because if you have any leaks it won't leave a level surface. Good luck. ..Clive

EddyCurrent
28-01-2014, 06:13 PM
Well I'll be having the wood burner going anyway, it says the pot life is about 40 minutes so surely that's enough for it to settle ?

For making the trough I was thinking about using this, do you think the epoxy will eat into it ?

10x10mm, 1.75M, Foam Sealing Tape Adhesive Strip, Draught Excluder, EPDM Rubber | eBay (http://www.ebay.co.uk/itm/10x10mm-1-75M-Foam-Sealing-Tape-Adhesive-Strip-Draught-Excluder-EPDM-Rubber-/251436618448?pt=LH_DefaultDomain_3&hash=item3a8aca52d0)

Edit: this is better, I'd missed the fact that previous stuff was only 1.75m long.
http://www.toolstation.com/shop/Ironmongery/Draught+Excluders/Extra+Thick+Weatherstrip+Brown/d170/sd2802/p70101

Clive S
28-01-2014, 06:24 PM
Well I'll be having the wood burner going anyway, it says the pot life is about 40 minutes so surely that's enough for it to settle ?

For making the trough I was thinking about using this, do you think the epoxy will eat into it ?

10x10mm, 1.75M, Foam Sealing Tape Adhesive Strip, Draught Excluder, EPDM Rubber | eBay (http://www.ebay.co.uk/itm/10x10mm-1-75M-Foam-Sealing-Tape-Adhesive-Strip-Draught-Excluder-EPDM-Rubber-/251436618448?pt=LH_DefaultDomain_3&hash=item3a8aca52d0)

Are you going to make a moat between the two rails so that they will be both at the same level, also the epoxy will rise up at the edges so make sure you have a wide enough flat plane to mount the rails on say at least 10mm each side. ..Clive

george uk
28-01-2014, 06:52 PM
hi


The mixture will certainly start of with a lower viscosity if it's warmer but it will also set faster as well (a rule of thumb from chemistry is a reaction will go twice as fast for every 10 deg C warmer)

I havent read the manuals on these yet, but

i suspect that this would be an exothermic reaction, ( , or endothermic ). If so, it might not react properly outside the recommended temp, and the suggested temp, may be the temp that it hardens the best at.
The rule of thumb mentioned above in the quote, would generally only apply to a stable compound, not a 2 part mix, especialy if that mix is exo or endo thermic

Wobblycogs
28-01-2014, 07:07 PM
I would put money on the reaction being exothermic. The epoxide ring is high strained configuration and and therefore would be expected to release a significant amount of energy upon opening. The other reactant is generally an amine and hydrogen can be made to fall off them quite easily normally (fall off being used in the technical sense here ;-) ).

From a chemistry point of view temperature generally only affects the speed of the reaction (within reason, you obviously get different products if the reaction catches fire). There are reactions where the end products you get are dependent on the temperature of the reaction but they aren't very common and I don't think that would be the case here as this chemistry is "aggressive". My guess is that this is more of a mechanical issue. To produce a strong end product the amine hardner needs to be able to cross link the epoxy. If the mixture is cold the molecules won't be very mobile so it's less likely the amine will bump into and be able to link to more than one epoxy leading to a product that is mechanically quite weak. The lower the temperature the worse this would be.

EddyCurrent
28-01-2014, 07:12 PM
Are you going to make a moat between the two rails so that they will be both at the same level, also the epoxy will rise up at the edges so make sure you have a wide enough flat plane to mount the rails on say at least 10mm each side. ..Clive

Yes, maybe one each end, I will leave 10mm each side.

EddyCurrent
28-01-2014, 07:14 PM
I realise there will be some heat generated by the mix but do you think the draught excluded can retain it ?

Neale
28-01-2014, 08:01 PM
I've used a fair bit of epoxy (usually thickened, though) for various boat repairs in the past and I can confirm that it is exothermic from personal experience. Fine in a wide, shallow, container but in a tall, narrow, container on a warm day - the pot was starting to smoke after a few minutes and it also starts setting much more quickly as it warms! For levelling, though, and assuming that it doesn't get too hot in the mixing pot, you are going to be putting a thin layer on a metal surface at ambient temperature so I doubt if temp will give problems; my guess is that viscosity is more important than setting time here, as long as it has time to run before it starts to gel.

As a solvent, epoxy resins don't seem to be as aggressive as, say, polyurethane resins. I used some small plastic pots for weighing out and mixing epoxy with no problem; first time I did the same with a 2-pack polyurethane, it went straight through the pot, the plastic tray I was using to catch the drips, and although the scales were metal and wiped clean, the stuff didn't do much for the plastic cover over the display which isn't quite so easy to read any more. My guess is that you are probably OK with the rubber sealing strip, but it would be easy enough to test a little bit first, maybe.

FatFreddie
28-01-2014, 08:47 PM
I realise there will be some heat generated by the mix but do you think the draught excluded can retain it ?
A 5mm layer of epoxy isn't going to generate enough heat to warm up a big chunk of metal far enough to generate any problems. Don't wait too long before pouring it though as it will generate heat in the pot.

Boyan Silyavski
28-01-2014, 09:02 PM
In fact when i mixed and poured the West System just 2 days ago, outside was around 19C. When i mixed it, for a second was a bit worried about the quantity i mix, but nothing happened. No heat at all.

Epoxy also suffers from humidity, i know this, as i live at 90% humidity near the sea.. So most epoxies i have used before/marine grade usually/ dried with a kind of mattish surface.

In the pdf says that the WS has no problem in high humidity working area.

njhussey
28-01-2014, 11:13 PM
Are you going to make a moat between the two rails so that they will be both at the same level, also the epoxy will rise up at the edges so make sure you have a wide enough flat plane to mount the rails on say at least 10mm each side. ..Clive

Clive, would you say it was easier to drill and tap all the holes for the rails after doing the epoxy?

Clive S
28-01-2014, 11:58 PM
Clive, would you say it was easier to drill and tap all the holes for the rails after doing the epoxy?

I take it that you have seen the pics that I posted. When the mdf sides were taken away you will find that the epoxy has crept up the sides a little. I then used a flat file to scrape the high sides away just until you see it marking the centre. I left mine to cure for about 3 days before removing the mdf. I just drilled through the epoxy and steel and then threaded in the normal way. It was way easier than I had thought.

When mixing the epoxy I did it by weight, I was told by the very helpful people at Wests to mix it in a wide container as that would produce the least heat. There is no problem with mixing it in one or two batches, I also used a hot air gun to flash the surface after it was poured to get rid of any bubbles in the surface. I believe that the proportions of the two part mix should be done accurately . Hope all this helps biggest tip is sealing the moat for leaks before you start as that will give you problems. ..Clive

njhussey
29-01-2014, 02:29 PM
The epoxy came today, only ordered it yesterday...nice!! Anyway, got it out of the box and gave it a shake to see how viscous it was. Not too bad and should pour quite nicely. I'm going to experiment with a small bit of steel and see how it mixes and settles between a couple of channels.

EddyCurrent
31-01-2014, 02:37 PM
Reactive Resins Syntac EPAFD epoxy with Synamin 201-c slow hardener.

This was the starting point using shims to level up the linear rail support beams.

114501145111456

A test piece was made using a 50x50 offcut, epoxy resin, draught excluder moat, http://www.toolstation.com/shop/Ironmongery/Draught%20Excluders/Extra%20Thick%20Weatherstrip/d170/sd2802/p70101

Temperature 17 deg C
Used kitchen digital scales to measure out by weight.
Mixed in a plastic cup, no melting of cup, no heat felt but it was only a very small amount.

Just after pouring, the viscosity was very good for pouring, it seemed to be runnier once the hardener had been added and mixed.

11452

You can see surface bubbles, I dragged a tooth pick/cocktail stick through the epoxy a few times and bubbles dispersed.
Next time I will mix the two parts more slowly so as not to introduce so much air.

11453

The viscosity was such that 2 hours later the remains in the plastic cup could still move like a thick fluid.
Slight leakage occurred at draught excluder butt joints e.g. corners, so I will be using a dab of glue at these points.

Following day about 20 hours after pouring.

1145411455

Depth of epoxy = 5mm
Draught excluder removed with a chisel no problem but it left a slight sticky residue that cleaned up okay with spirits and the epoxy captured a very small amount of foam in it's outer skin.
A slight meniscus can be seen but this was expected, 'Clive S' describes how best to remove this.
The epoxy is fairly hard but you can tell it has a day or two to go until it's cured.

I would say this test was a success and I have no problem with using this on the machine.

njhussey
31-01-2014, 02:43 PM
Where's the pics Eddy???!! Need pics :eagerness:

EddyCurrent
31-01-2014, 03:17 PM
Can you see them now ? I was doing a long edit, I can see them here okay.

EddyCurrent
31-01-2014, 03:28 PM
Earlier I was having problems getting my spindle running in vector speed mode, this is now sorted thanks to ABB

Spindle ELTE, V=220, A=9.5, Speed=24000 rpm, Kw=2.2
Drive - ABB ACS355 2.2kw 01x-09A8-2

The problem was it would work great in v/f mode but not in vector mode.
Following many emails and parameter changes without success an AB engineer paid me a visit and it was sorted out in a morning. (I don't think you would get this support with a Chinese VFD)

This was the solution;

1) Drive firmware changed from 5060 to latest 5090. Version 5090 is known to contain improvements for ‘special motors’
2) Switching frequency par. 26.06 set from ‘4kHz’ to ‘16kHz’. Par. 26.07 = ON(LOAD).
3) Rescaled group 99 motor data to 200Hz equivalent, (i.e. 200Hz, 11500rpm, 9.5A, 110V,1.1kW)…changing this allowed the motor to achieve 24000rpm for the first time during testing
4) Adjusted ramp rates (par. 22.02 = 5s and in particular 22.03 = 10s), also introduced S-shape (par. 22.04 = 1s)
5) Adjusted non-user parameter 112.08 from ‘40’ to ‘10’ (made motor sound quieter, particularly at low speeds)
6) Speed controller ‘Autotune’ performed (using par. 23.05), resulted in par. 23.01, Gain = 3, par.23.02 Integral = 2s and par. 23.04 Accel Comp = 1.45s

njhussey
31-01-2014, 03:29 PM
I was too impatient.....:shame: I'm going to the DIY store this weekend to get some draft excluder to do this on my pieces of angle for the X axis carriage mounting points next week...away for the weekend so can't do it :(

11458

EddyCurrent
31-01-2014, 03:33 PM
I'm going to the DIY store this weekend to get some draft excluder to do this on my pieces of angle for the X axis carriage mounting points next week...away for the weekend so can't do it :(

Obviously make sure it's thick enough, the stuff I got was 7mm thick x 15mm wide, very close to the wire for a 5mm deep epoxy but manageable with care

Washout
31-01-2014, 03:35 PM
You could also try Easy Composites - they do low viscosity infusion resins with a variety of timed hardeners, which I've used for vacuum infusion projects - the resin needs to be thin for that as you are essentially sucking it through your carbon/kevlar/glass fibres. The West System is probably similar, but if you need another price point......

njhussey
31-01-2014, 03:51 PM
Obviously make sure it's thick enough, the stuff I got was 7mm thick x 15mm wide, very close to the wire for a 5mm deep epoxy but manageable with care

I don't mind if it's 5mm or 4mm as long as it's flat but I'll bear that in mind when I'm looking for it...

cncJim
31-01-2014, 04:08 PM
Thanks for posting the pics eddy! The foam seems an excellent quick way to do this task. :smile:



... the epoxy captured a very small amount of foam in it's outer skin.


I wonder if applying some sort of grease to the draft excluder before pouring would help with that?

Jim

Clive S
31-01-2014, 04:11 PM
You can see surface bubbles, I dragged a tooth pick/cocktail stick through the epoxy a few times and bubbles dispersed.
Next time I will mix the two parts more slowly so as not to introduce so much air.

Ready Steady Eddy-epoxy2.jpg

I found that a warm air gun flashed across the surface got rid of the bubbles. As a matter of interest the Wests System was still like thick water 6 or 7 hors after the pour before its started the cure. With no sticky stuff on the top when cured. Also the mixing was just done with a flat bit on thin ply and gently stirred it round. ..Clive

EddyCurrent
31-01-2014, 04:15 PM
I wonder if applying some sort of grease to the draft excluder before pouring would help with that?Jim

Vaseline maybe (no jokes now!)

EddyCurrent
31-01-2014, 04:20 PM
I found that a warm air gun flashed across the surface got rid of the bubbles. As a matter of interest the Wests System was still like thick water 6 or 7 hors after the pour before its started the cure. With no sticky stuff on the top when cured. Also the mixing was just done with a flat bit on thin ply and gently stirred it round. ..Clive

You mentioned this before so I tried a hair drier (it's the wife's, no use to me now) on it's lowest speed but it was moving the epoxy round like the seas at Cape Horn.
Yes I think this epoxy was still flexible after 6 to 7 hours but maybe just beyond any self leveling properties on the scale required.
It's interesting you confirm the slow mixing method.

njhussey
31-01-2014, 04:22 PM
I was told by someone to mix it in one container and then transfer it to another for the final bit of the mix and that way any unmixed bits round the sides/bottom edge etc. either get left or poured into the new container and you don't get any soft sticky bits...

Clive S
31-01-2014, 04:45 PM
You mentioned this before so I tried a hair drier (it's the wife's, no use to me now) on it's lowest speed but it was moving the epoxy round like the seas at Cape Horn.
Yes I think this epoxy was still flexible after 6 to 7 hours but maybe just beyond any self leveling properties on the scale required.
It's interesting you confirm the slow mixing method.

I meant to say hot air gun straight after the pour so the waves won't matter. I was told by the people at Wests a good way would be to mix in a container with a small hole at the bottom on the side (say 7mm) with some tape over it, when mixed remove the tape and let the epoxy flow out of the hole into your trough that way you don't get the bubbles. I never tried though. ..Clive

EddyCurrent
31-01-2014, 04:53 PM
I meant to say hot air gun straight after the pour so the waves won't matter. I was told by the people at Wests a good way would be to mix in a container with a small hole at the bottom on the side (say 7mm) with some tape over it, when mixed remove the tape and let the epoxy flow out of the hole into your trough that way you don't get the bubbles. I never tried though. ..Clive

That was likely okay with your moat design but with the draught excluder there's not much height before the banks are breached. That sounds like a great idea for pouring.

Also I'd like to thank everyone for their input because I feel I've learned a hell of a lot more about this epoxy idea these last few days.

Wobblycogs
31-01-2014, 05:41 PM
Brilliant update Eddy, great idea with the draught excluder.

I've watched a few videos about clear coating wood with epoxy. To get the air bubbles out they normally play a blow torch flame over the surface for a fraction of a second. I guess the faster you can apply the heat the less you move the epoxy around. They always remove the majority of the bubbles before pouring though and I've seen two good techniques for this. The first requires some skill, you pour the epoxy from one container to another but lift the top container up as high as you can creating a very thin but constant stream. It seems the thin stream forces the bubbles out on it's way down. I've tried this and it works but it's easy to screw up and end up with epoxy everywhere. The other is to pour the epoxy into a big tub and put it under slight vacuum which will suck all the bubbles to the top, obviously you need some way to make a vacuum though and you've got to be careful not to fill your vacuum making device with epoxy by accident :-). Next time I need to de-bubble some epoxy / resin I'm going to give the vacuum method a go as I have a spare vacuum cleaner hanging around.

What are you planning on doing about the meniscus? I was wondering if it might be worth trying to route a chamfer into the epoxy as that would remove the meniscus, clean the edge and help stop it chipping all at the same time.

JAZZCNC
31-01-2014, 07:04 PM
You could also try Easy Composites - they do low viscosity infusion resins with a variety of timed hardeners, which I've used for vacuum infusion projects - the resin needs to be thin for that as you are essentially sucking it through your carbon/kevlar/glass fibres. The West System is probably similar, but if you need another price point......

Don't know how I've missed this debate.? . . . . I've always used Infusion resin's with slowest hardner I could find for doing this. Most Infusion resins will work with slow hardener.

Lee Roberts
31-01-2014, 09:50 PM
Also I'd like to thank everyone for their input because I feel I've learned a hell of a lot more about this epoxy idea these last few days.

Me too, thanks everyone !

EddyCurrent
31-01-2014, 11:23 PM
What are you planning on doing about the meniscus? I was wondering if it might be worth trying to route a chamfer into the epoxy as that would remove the meniscus, clean the edge and help stop it chipping all at the same time.

I'm thinking it would be difficult to control a router for that operation. The method I propose is to use a file where you stop when the central epoxy starts to show signs of contact, then run a bead of liquid nails along each edge of the epoxy, run your finger along, thus creating a nice fillet between the epoxy and the underlying metal.

njhussey
01-02-2014, 12:17 AM
I meant to say hot air gun straight after the pour so the waves won't matter. I was told by the people at Wests a good way would be to mix in a container with a small hole at the bottom on the side (say 7mm) with some tape over it, when mixed remove the tape and let the epoxy flow out of the hole into your trough that way you don't get the bubbles. I never tried though. ..Clive

One slight problem I can see with playing a heat gun over the epoxy is that the moat is foam...heat and foam aren't the best of friends in my experience! Only takes for the heat to be on a fraction of a second too long and you've a leak in your moat!

I think I'm going to do a mix of ideas for getting the bubbles out. Firstly I'll mix it slowly in one container and hopefully not induce too many bubbles. Then I'll transfer it to a second pot to ensure its all mixed and no pockets of just resin. This pot will have a hole in the side to aid pouring. I might even pinch a bit of 100 mesh SS filter wire from the works to strain it through. This should trap all the bubbles on the way through the mesh.

Some cracking ideas in this thread...

EddyCurrent
01-02-2014, 12:24 AM
Neil,
The heat I tried with the hair dryer was not enough to affect the foam, I kept it moving, but the thing is in my case it did not help with the bubbles. Maybe heat with less force would work ? it's just that with the draught excluder method there is not much room to create a tidal swell in the epoxy,

njhussey
01-02-2014, 12:28 AM
Hair dryer and heat gun are different beasts though...hair dryer will never get hot enough to melt the foam. Heat gun would if you hovered in one place too long I'd wager...

njhussey
01-02-2014, 12:30 AM
It's a compromise with the foam of enough heat to expand the air bubbles to pop them and not too much heat to melt the foam :)

EddyCurrent
01-02-2014, 12:48 AM
Dragging the tooth pick worked for me and it physically moved the epoxy about thus aiding the self leveling process.

njhussey
01-02-2014, 12:56 AM
You can't beat low tech...I can't wait to start playing with the epoxy next week!

EddyCurrent
02-02-2014, 03:29 PM
It's done !

This is before showing the moat in place. Clive S recommended 10mm epoxy each side of the linear rail so with my rail being about 20mm wide the epoxy bed has to be 40mm wide. Because my support beam is 50x50x3 box section it only left 5mm spare each side which meant the draught excluded would have been on the radius of the box section, that's why I clamped strips of wood each side so as to fully support the draught excluder. You can see I've coated the joints and any gaps with sealer.

1148511486

The gear used and the environmental conditions at the start. I used an old ice cream tub and a sawn off milk carton, the epoxy was mixed in the milk carton then poured into the ice cream tub with a thin stream as suggested previously. I'm not sure this did much but at least there was no mess created. The ice cream tub had a 7mm hole on one side, right at the bottom, with a piece of tape across and this proved to be perfect for pouring. Humidity is quite low because I always have a dehumidifier in there.
The calculated volume of my moat to give 5mm depth of epoxy was about 605300 mm^3 and it worked out that 500g of epoxy plus 250g of hardener was just right.

1148711488

This is after the pour, you can see the meniscus. There were no leaks and there was never any risk of it overflowing the moat. The epoxyducts were about 10mm wide and I'm thinking they could have been wider, definitely no smaller, the reason being that with this viscosity it needs a decent channel to flow down otherwise I would not be confident that the whole surfaces were at the same level.

11489114901149111492

Clive S
02-02-2014, 05:20 PM
Eddy That looks nice re the moat I did find that my moat could have been a little wider although I did have two of them. I am sorry that I forgot to mention that before but you have plenty of width now in the centre even you don't get rid of the meniscus. :thumsup: ..Clive

EddyCurrent
02-02-2014, 05:33 PM
I think the meniscus extends about 5mm across the width so with that each side it leaves a 30mm flat section in the middle, as you say that will be plenty for rail mounting. A file will soon sort out the meniscus removal later.

I forgot to mention that I had an epoxyduct at each end, plus, and it might be going extreme, I gave the epoxyduct pieces of wood a coating of sanding sealer thinking that the bare wood might soak up some of the epoxy, unlikely though it might be.

11493

Also in the excitement I forgot to put Vaseline on the sides of the draught excluder but not to worry it just means a bit of sandpapering later.

njhussey
02-02-2014, 05:48 PM
Looking good Eddie, I've ordered the draught excluder so will be finishing off the frame to the point where I decide whether to paint it first or epoxy and then paint. I quite fancy getting it powder coated...

EddyCurrent
02-02-2014, 06:33 PM
I had those thoughts myself but decided to epoxy onto bare metal. I had put metal primer on the box section beam but before putting the moat on I sandpapered it off the top. My intention is to fit the linear rail and paint over everything up to that.
Also sod's law, my glasses fell to bits as I was getting set to pour, the frame had broken letting a lense drop to the floor, had to quickly superglue it all back together.

I know this is somewhat less than scientific but I just had a play with the sample epoxy pour I did 3 days ago, a scriber barely scratched the surface and a centre punch made no more of a mark in it than it did in the steel box section. Overall I'd say that stuff was rock hard.

njhussey
03-02-2014, 09:51 AM
I had those thoughts myself but decided to epoxy onto bare metal. I had put metal primer on the box section beam but before putting the moat on I sandpapered it off the top. My intention is to fit the linear rail and paint over everything up to that.

I'll take the paint off where the epoxy will go with a flapper disc on the angle grinder so it's back to bare metal. I guess the epoxy would be OK when the paint was in the oven (180C) but will get it painted before just in case.


I know this is somewhat less than scientific but I just had a play with the sample epoxy pour I did 3 days ago, a scriber barely scratched the surface and a centre punch made no more of a mark in it than it did in the steel box section. Overall I'd say that stuff was rock hard.

That's good to know that it sets rock hard. Will be interesting to hear how you get on with the filing the meniscus off, I can imagine it clogging the file. I might have a go at how Graham (Wobblycogs) suggested getting the meniscus off with a router. If you have a bit with a guide bearing and ran the bearing on the epoxy surface and the router plate on the side of the box section I can see it being quicker. Might have a play when I get there...

EddyCurrent
03-02-2014, 09:57 AM
Will be interesting to hear how you get on with the filing the meniscus off, I can imagine it clogging the file.

A course bastard file works great, then finish off with fine sandpaper wrapped around a wooden block, making sure not to contact the middle area.


I might have a go at how Graham (Wobblycogs) suggested getting the meniscus off with a router. If you have a bit with a guide bearing and ran the bearing on the epoxy surface and the router plate on the side of the box section I can see it being quicker. Might have a play when I get there...

You're on your own with that idea, keep some bandages handy

Clive S
03-02-2014, 10:16 AM
I'll take the paint off where the epoxy will go with a flapper disc on the angle grinder so it's back to bare metal. I guess the epoxy would be OK when the paint was in the oven (180C) but will get it painted before just in case. I had my frame powder coated with the rail tops covered with 50mm masking tape I thought it would burn off but it didn't. Then a scraper removed it quite ok. ..Clive

njhussey
03-02-2014, 10:19 AM
That's good to know Clive, will save a few slips with the flapper disc that's for sure!!

Wobblycogs
03-02-2014, 11:06 AM
I think a bearing guided bit would work but that wasn't quite what I had in mind. I'd try a chamfer bit with the depth set slightly less than the depth of the epoxy. Run the fence of the router along the edge of the steel. You'd probably need a couple of passes as the leading edge of the router would ride up a little but I'd guess it'd take longer to set up the router than it did to clean up the epoxy. I think this would probably work better with the more often used clamping-wood-to-the-steel method of keeping the epoxy in while it's poured as you wouldn't have to be quite so careful about correctly setting the depth of cut.

Great looking result Eddy.

njhussey
03-02-2014, 11:38 AM
This is what I was thinking of...

11498

Clive S
03-02-2014, 11:43 AM
This is what I was thinking of...

11498

That would work until you get to the end where the router body stop the cutter getting to the end. You could do this with a file in a few minutes :beer:

EddyCurrent
04-02-2014, 11:40 AM
It's been cold overnight here recently so this is the third day since pouring the epoxy, it's set but I'm not confident about taking the moat off just yet.

njhussey
11-02-2014, 04:42 PM
Must be about time for an update???

cncJim
11-02-2014, 07:46 PM
Yeah c'mon eddy! How are the rails looking?

EddyCurrent
12-02-2014, 09:47 PM
There's not a lot of progress to report, but thank you kindly for your support.

It took only a few minutes to remove the meniscus using a course file, because there was 10mm each side of the rail it meant there was no need to get it perfectly flat across the whole width. I did run a bead of liquid nails down each side of the epoxy just to give a nice transition onto the metal.
Got the rails on, one support beam painted, 20mm aluminium gantry support bracket fitted and ballnut bracket attached.
Ball screw temporarily installed just to show actual position. Tried to keep rail and ballscrew in same horizontal plane as much as possible.
I had to regrind some drills to make counter boring tools for the cap head screws.

1158811589115901159111592

Showing end of beam with rail, epoxy, 6mm internal flat bar to give extra thickness for rail mounting screws, glued it in with Gorilla Glue and worked great.
11593

njhussey
12-02-2014, 10:05 PM
Looking good! Just wish I had the time to spend a few hours in one go on mine...

Wobblycogs
12-02-2014, 11:12 PM
Not a lot to report! I'd be pleased to get that much done in ta month. Looking really good as well. I got some counterbores from RS of all places, they only cost about a fiver each and they are more than good enough for aluminium.

GEOFFREY
13-02-2014, 12:39 AM
That does look nice Eddy - well worth posting the photos. G.

cncJim
14-02-2014, 09:10 AM
Excellent! Looking really good, the epoxy looks like it worked really well, are you pleased with the results? Would you do anything different next time? Good job! Jim

EddyCurrent
14-02-2014, 11:40 AM
Would you do anything different next time? Good job! Jim

1. Remember to put Vaseline or similar on the draught excluder. Although it easily came off with an old chisel, it did leave a tiny bit of 'fluff' stuck to the epoxy.
2. Leave the epoxy as long as possible before fitting the rails. I clamped one down three days after pouring but removed it again a couple of days later. I discovered it had sunk into the epoxy slightly, obviously there is a lot of pressure when it's fully bolted down. All I did was mix up some 5 minute epoxy and filled in the very small grooves but it would also have been okay just to leave it. I suppose if your bolts were slightly at an angle, the rail could sink into the epoxy also at an angle which would not be good, so wait about a week before fully tightening and make sure your bolts are exactly vertical.
3. Maybe the epoxy need not have been so thick ? I don't know if there is a point when the epoxy is so thin it just cracks apart ? maybe it has to be about 5mm in order to have some strength ?

njhussey
14-02-2014, 12:30 PM
I'll leave mine for a week then to let it fully cure and try to remember to use Vaseline on the foam. I am wondering whether to drill all the holes before epoxying the rails and coating the bolts with Vaseline so the epoxy doesn't stick, would have to file the meniscus off round each hole though. We have a mag drill here so it would mean perfectly square holes, hmm...decisions decisions...

EddyCurrent
14-02-2014, 02:05 PM
Drill all the holes after the epoxy has set.

ba99297
14-02-2014, 04:15 PM
Eddy very good work.
I would like to ask you a couple of things about your construction.
I saw that the rectangular beams that you have applied the epoxy resign are not welded but bolted with the frame. What is the purpose of this choice? After applying the epoxy resign, is there any way to adjust the beams with the screws?
Then i would like to ask if everything is ok with the resign and how much did it cost? Is it much cheaper than west system epoxy?
Finally what plan are you going to apply for your gantry? You will go with steel or aluminium?
Keep trying very good job so far.
Thank for your time

Vagelis

EddyCurrent
14-02-2014, 09:13 PM
I saw that the rectangular beams that you have applied the epoxy resign are not welded but bolted with the frame. What is the purpose of this choice? After applying the epoxy resign, is there any way to adjust the beams with the screws?

There seems to be two main ideas, one is to bolt the beams like I did then level the top using shims between the bolted flanges. The other idea is to fully weld the frame then use epoxy to level the top.
What I found was that after welding the flanges to the top beam it made it bend, this was expected. I bolted it to the frame and got it almost level but there was a downward dip at the overhanging end. I decided therefore to epoxy the top. Once the epoxy has set you do not want to be doing anything with the bolts holding the beam otherwise you could make it not level again.



Then i would like to ask if everything is ok with the resign and how much did it cost? Is it much cheaper than west system epoxy?

The resin appears to be identical to the West System in this application, Epoxy Resin ideal for fibreglass repair and general use (http://www.resinstore.com/epoxy-packs.html)
21.85 GBP + VAT + shipping



Finally what plan are you going to apply for your gantry? You will go with steel or aluminium?

Aluminium, L shape using 100x50x6 aluminium box, faced with a 6mm x 150 aluminium plate. All glued with Gorilla Glue then bolted. (thanks to kingcreaky for ideas and info, http://www.mycncuk.com/forums/gantry-router-build-logs/6530-machine-month.html)

116101161111612

Clive S
15-02-2014, 12:01 AM
The resin appears to be identical to the West System in this application, Epoxy Resin ideal for fibreglass repair and general use (http://www.resinstore.com/epoxy-packs.html)
21.85 GBP + VAT + shipping I'm sorry Eddy but how can you say it is identical unless you have tried both types, I seem to remember you had a small problem with sinkage after about 3 days and you had to refill the surface I did not have that problem at all, I did not have any surface problems, the cure did not start for about 6 hours so plenty of time for it to settle. I am not trying to dis you by any means but I think it is only fair to others that are reading this to know the facts and it is up to their choice which to use. The Wests System is about twice the price but you only use it once so you take your chance. I spoke with the people at Wests about the suitability of their product regarding the shrinkage and cure times etc they were more than helpful. Rant over, nice job by the way ..Clive

Jonathan
15-02-2014, 03:12 AM
I'm sorry Eddy but how can you say it is identical unless you have tried both types, I seem to remember you had a small problem with sinkage after about 3 days and you had to refill the surface I did not have that problem at all, I did not have any surface problems, the cure did not start for about 6 hours so plenty of time for it to settle

+1

I'd consider the epoxy 'squashing' slightly when the rail was attached a bit of a disaster, but it all depends on what accuracy you're striving for.

EddyCurrent
15-02-2014, 11:12 AM
I don't think anyone has tried both epoxy products side by side but it seemed to me that if there was a difference then I would not be able to tell. I tried marking it with a scriber and used a centre punch on it and both times it was as hard you could wish for.

It wasn't shrinkage, it was the fastened down rail compressing the epoxy slightly.

Maybe nobody has removed their rails to see if the epoxy has moved ? maybe everyone else let it cure longer than I did ? maybe I torqued the rails down harder ? maybe my environmental conditions meant it had to cure longer ?. There are so many variables it's not possible to compare two situations. All I know is it should be left as long as possible after 3 days before fitting the rails, I seem to remember seeing 9 days somewhere but can't find the reference again.

Also I do not see it as a bit of a disaster, this is a DIY solution, it would not be used in a commercial machine (I hope !). The amount of sinking I'm talking about is less than 10 thou. , the sinking was uniform along the length, it only occured along the 'feet' of the rail, not in the middle so was easy to repair using the 5 minute epoxy and an old credit card , even if I had not repaired it it would have been fine because both rails were still in the same plane.

EddyCurrent
15-02-2014, 09:48 PM
Setting up the gantry rails. The top rail has been fitted alongside a straight edge parallel to the front face of the gantry, this is the bottom rail being positioned. I put a bearing block on the top rail and fastened a G-cramp to it, then I attached a DTI with a magnetic base to the G-cramp. Sliding the block along showed that the rails were within 0.002" of parallel. Now to drill, tap, and fit the bottom rail.

11621

Wobblycogs
15-02-2014, 10:46 PM
Have you managed to bolt those two pieces of box section together inside (middle picture in power #180)? I'd love to know how you managed that if you have. I seriously considered trying that but there was no way I could think to get my arm in the box section and tools would be hellishly fiddly.

JAZZCNC
15-02-2014, 11:17 PM
the sinking was uniform along the length, it only occured along the 'feet' of the rail, not in the middle so was easy to repair using the 5 minute epoxy and an old credit card , even if I had not repaired it it would have been fine because both rails were still in the same plane.

Don't talk daft any sinkage is Bad news and complete disaster.!! . . . Plus if they have sank so how do you know they are on the same plane.? Impossible to say that without some way to measure.

All this said for wood use then this will still be plenty good enough so it wouldn't bother me.

Regards the Epoxy then I agree West is Good and market leader but I've used other Infusion resin Epoxy's with no problems. Believe Rushing was your problem.!!

EddyCurrent
16-02-2014, 11:59 AM
Don't talk daft any sinkage is Bad news and complete disaster.!! . . . Plus if they have sank so how do you know they are on the same plane.? Impossible to say that without some way to measure.

Over the years I've not had many 'disasters' that could not be recovered from, in fact working in Engineering Maintenance it's not even an option. In this case one method would have been to remove the epoxy and start again but I chose the method I did because that was fine for me, anyone else should choose their own recovery method.

I measured using a DTI from the face of the surrounding epoxy that had not been touched, I have 10mm each side of the rail 'spare'


All this said for wood use then this will still be plenty good enough so it wouldn't bother me.

Same here


Regards the Epoxy then I agree West is Good and market leader but I've used other Infusion resin Epoxy's with no problems. Believe Rushing was your problem.!!

I'm sure there are other resins that can do the job as you say.
Yes, rushing was most likely the problem.

Lee Roberts
16-02-2014, 03:37 PM
Looking sweet eddy, keep up the good work.

.Me

EddyCurrent
16-02-2014, 08:59 PM
Have you managed to bolt those two pieces of box section together inside (middle picture in power #180)? I'd love to know how you managed that if you have. I seriously considered trying that but there was no way I could think to get my arm in the box section and tools would be hellishly fiddly.

The rails on the gantry are 800mm long, they have 15 bolt holes. When I drilled the holes in the gantry to mount the bottom rail I made every other one 6.5mm, the others were 3.2mm tapping size. The 6.5mm holes, all 7 of them, were drilled right through both box sections to take 6mm hex bolts and that's what you can see in the photo. To get the bolts in the holes I used a magnet on a telescopic rod (Aldi's best), to get the nuts on I used a long thin piece of wood with double sided tape on one end. To the tape I stuck a nut, put some Loctite in it and 'stuck' a spring washer to it also with Loctite, this was lowered into the box section and using a long allen key on the head of the hex bolts (through the 6.5mm hole) I managed to attach both washer and nut. The other end of the thin stick had a taper or wedge cut out of it and this was used to stop the nut turning by wedging the stick between it and the inside face of the box section, the bolt was then tightened.
I glued a piece of 6x30 mild steel flat bar inside the box section then drilled and tapped all 15 holes for the rail thus making all 15 holes 3.2mm tapping size.

6x30mm flat bar glued inside to provide tapped holes for bottom gantry rail mounting.

11626

Stick, telescopic magnet

116271162811629

EddyCurrent
17-02-2014, 08:56 PM
Once I got the rails fitted to the gantry and the two lower bearing blocks added it was easy to see how to square everything up.
The gantry is bolted to the carriages at each end, the bolts were left slightly loose until the whole assembly was squared.

11636

First an engineers square was adjusted to be exactly 90 deg. by using the flip over method mentioned previously, the fact it's a cheap Aldi one does not matter as you will see.
As silyavski pointed out recently, the Hiwin rails and bearing blocks have a machined side that should be used as a datum, so to these faces of the lower bearing blocks I clamped the engineers square.

11637 11638

All I had to do then was measure the distance between the engineers square and the long rails using a vernier. This was done at the end of the square and right up at the gantry so obviously when they read the same the gantry is at right angles to the long rails. The key point is that it's the two sets of rails that are being squared and not just the gantry frame. Also with regard to the cheap square, it can now be slid over to the other side of the gantry as it's clamped to the bearing blocks, and a similar reading can be made with the vernier. If the square was out of adjustment then the error would be multiplied at this side because the two long rails are exactly parallel. Once everything was adjusted the gantry securing bolts were tightened.

cncJim
17-02-2014, 09:08 PM
Thanks for the explanations eddy. Machine is looking great!

EddyCurrent
28-02-2014, 09:07 PM
Without a doubt the Z axis is the hardest part, progress so far.

I used a bandsaw to cut the profiles and then a static belt sander to clean up the profiles, internals cleaned using files. The motor mount consists of two 6mm plates which are glued and screwed together, the motor adjustment slot and slotted holes were cut using a drill, files, flapdisc.
The backplate where the ball screw is attached was 'milled' using my overhead pneumatic pin router and hand guiding the aluminium plate against a straight edge that was gradually moved across half a cutter width at a time.
The cutter was a standard cheap 2 flute 6mm dia. TCT router bit running at 9000 rpm and it worked great, only clogging if my depth of cut exceeded 0.5mm, I had a good jet of air blowing on it and just cutting dry.

11715 11716 11717 11718

fvfdrums
28-02-2014, 09:30 PM
Looking good :)

njhussey
28-02-2014, 09:48 PM
Looking good, like the look of lots of shiny aluminium. My build has stalled...

EddyCurrent
28-02-2014, 09:56 PM
Looking good, like the look of lots of shiny aluminium.

But it's knocking my pan in all the swarf and chippings underfoot, that's why I stick to wood :glee:


My build has stalled...

Not good, but it sounds like you have a lot going on just now.

EddyCurrent
01-03-2014, 09:43 PM
I did a daft thing yesterday and tried to knee jerk my out of it but I knew it was no good and laid awake from 6am this morning thinking what to do, anyway it's back on track now.

I thought it would be a good idea to mill two grooves for the Z axis rails to sit in, maybe 0.5mm deep so using my wood router I set about it with a 6mm cutter. After installing the rails and sliding the assembly into the bearing blocks it was tight, noisy, juddering. So further investigation revealed the two grooves were not flat and the rails were leaning outward a bit, now this is where the knee jerk bit started, I put epoxy putty on the back of two of the bearing blocks and bolted it back up, it was better but not perfect. Anyway after thinking about it this morning I decided to route the grooves again but this time using one large cutter and it worked great, it took two goes to skim it but the results are so good there is virtually no resistance when sliding the front plate along. It meant though that I needed 1mm shims under the bearing blocks due to the extra depth I had to take out of the rail grooves but that worked out fine. There is a slight gap each side of the rails due to the grooves being slightly wider however I will run a bit of epoxy into those gaps and that should keep the rails nicely in place.
I'll have to divert onto another bit now as I'm waiting for the Z axis ball nut to arrive from China.

Extra hole in rail = broken tap in orignal.
11725

clamps are to stop front plate dropping out of the bearings and loosing my balls.
11726

njhussey
03-03-2014, 09:54 AM
Looking good there :applause:, nice to see it all coming together.

EddyCurrent
04-03-2014, 09:14 PM
11753

Compound brackets for ball screw FK12 / FF12 type bearings, this is how I made them.
Clamp all parts of bracket together, position bearing block on brackets and clamp, drill 4 mounting holes in brackets using bearing block as a guide, disassemble bracket pieces and drill largest feasible hole in each piece, in my case about 19mm using a cone cutter (it's hard work and hardly cuts), bolt bearing block to a bracket piece with some spacers between, mount in lathe chuck, use boring bar to open hole out to final size, repeat for other bracket pieces.

11754

Ball screw mounted to gantry, it was on and off so many times it could have put itself together in the end, this was due to adding shims here and there to get it working smoothly. I was forced to sup a can of Guinness to use the cut up tin for shims.

117551175611757

Jonathan
04-03-2014, 09:24 PM
Wait, you have a lathe yet you were asking to buy (http://www.mycncuk.com/forums/items-wanted/7245-bk12-bearing-block-wanted-1-off.html) a BK12 bearing block, instead of just making a better one. This makes no sense.

EddyCurrent
04-03-2014, 09:36 PM
Wait, you have a lathe yet you were asking to buy (http://www.mycncuk.com/forums/items-wanted/7245-bk12-bearing-block-wanted-1-off.html) a BK12 bearing block, instead of just making a better one. This makes no sense.

Edit: Previous ramblings removed.

I bought some sausage for breakfast but we have a mincer so why didn't I make some better ones, I got some logs delivered for my stove but I have a saw and an axe so why didn't I got into the wood and chop some better ones, I bought some cheap jogging trousers to wear in the shed but we have a sewing machine so why didn't I make some better ones, I bought some aluminium but I have a gas burner so why didn't I melt some empty Guinness cans to make a better billet ?

When I used to do peoples annual appraisals at work there was a criteria called 'Seeing Patterns', so do yourself a self assessment on this and there's your answer.

EddyCurrent
10-03-2014, 03:41 PM
Jonathan said he won't use BK12 bearings and I think he's half right.
The housings seem to be okay provided they are dimensioned correctly for the bearings used, but it's the supplied bearings themselves that are extremely suspect.
I just stripped a couple out, one had Japan bearings the other China bearings, one had the bearings facing opposite directions, one had both bearings facing the same direction (keep in mind these are angular contact bearings), the China bearings had no grease whatsover in them.
So it's a good job I stripped them down but now they have to be sorted out.
First I had to understand about AC bearings so found this;

Bearings for universal matching (http://www.skf.com/group/products/bearings-units-housings/ball-bearings/angular-contact-ball-bearings/single-row-angular-contact-ball-bearings/bearings-for-universal-matching/index.html)
Internal clearance and preload (http://www.skf.com/group/products/bearings-units-housings/ball-bearings/angular-contact-ball-bearings/single-row-angular-contact-ball-bearings/internal-clearance-and-preload/index.html)
(click on the 'table' links near the bottom)

Now I understand I need to reassemble according to those diagrams but can't decide if Fig2 or Fig3 arrangement (see first link above) is best, opinions please.

Edit: After reading this
http://www.mycncuk.com/forums/linear-rotary-motion/6968-angular-contact-bearings-back-back-further-apart.html I'm thinking Fig2.

and this
http://www.mycncuk.com/forums/linear-rotary-motion/6316-bk12-end-float.html

Lee Roberts
10-03-2014, 05:27 PM
Back to Back Eddy.

.Me

EddyCurrent
10-03-2014, 06:03 PM
That's Fig2 then, thanks.
I also decide to get some new bearings for the blocks because the backlash on the China bearings was serious. I fitted a shim between the outer races but with the locknut fitted there was still slight play, the shim was the thickness of a Guinness can which in this application is thick. I also took a skim off the block to make sure the outer races were being clamped.

Also I'm sure I have a bent ball screw on the Y axis, it's not something I've done myself, on the last 1/3rd of it as you rotate it by hand it goes, slack,tight,slack,tight,etc. and using inside calipers between the screw and the gantry the gap goes big,small,big,small,etc. I'm not 100% yet but it might be the turned down section on the end is off centre.

I may have to get into this

http://www.roton.com/screw_shaft.aspx

EddyCurrent
10-03-2014, 10:10 PM
As requested layout info for panel, please refer to schematics posted previously.

Starting top left.

Panel isolator, AM882's, ABB Inverter
PSU for stepper drivers, FL2, FL1, CB2, 5V PSU, 24V PSU
CB1, K1, K2, K5, Breakout Board with spindle board and K6, Smooth Stepper (mounted on panel side (aargh I hate that))
Terminal rail, K3, K4, PILZ Safety Relay

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On the close up photo you can see 3 wires (77,75,24N) going to a piece of vero board located on a stand-up on the bob, that's K6 the transistor relay for flashing the lamp (see schematic)
It got a bit crowded and I've not got the fans in yet ! the grey wire hanging down is just the spindle I have lashed in temporarily.

Added a limit override switch (it's a spring return type so you can't accidentally leave it on), still need to label up everything on front.

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Clive S
10-03-2014, 11:52 PM
I also decide to get some new bearings for the blocks because the backlash on the China bearings was serious. I fitted a shim between the outer races but with the locknut fitted there was still slight play, the shim was the thickness of a Guinness can which in this application is thick. I also took a skim off the block to make sure the outer races were being clamped. I think I remember Dean saying some time ago that the tubular spacers on the BK bearings are not always long enough and that he had made fresh ones. It is there to enable the lock nut to push the inner races together.
I might be talking crap though :very_drunk: ..Clive

EddyCurrent
10-03-2014, 11:58 PM
Clive, you're not talking crap but in this case the spacers are okay, it's the bearings themselves, the inner and outer races are dimensioned wrong so there is no gap for preload. I've been reading that the bearings should be obtained as a pair.

njhussey
11-03-2014, 09:18 AM
After reading this I've just been looking closer at one of my fixed end bearing blocks and it has play in the bearings. The floating end has a NSK Japan bearing in, not sure about the fixed as I've not taken it apart yet but I can bet my bottom dollar that they'll be cheap Chinese bearings...

njhussey
11-03-2014, 02:48 PM
Yep....chinese bearings (ungreased) and face to face so the inner races were not being tensioned...need a shim and some grease and see how they fare...

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EddyCurrent
11-03-2014, 09:09 PM
Looks like Z axis ball screw has issues too. Noticed while driving it up and down, with the front plate off, the ball nut and bracket were fine at the bottom but the more they reached the top the more they oscillated side to side. I took it all to bits and found two things, the turned down section at the driving end was slightly off centre and the the whole turned down section was bend to one side. With the ball screw resting in two V blocks it was rotated and a DTI measured a deviation of 0.8 mm at the end where the pulley sits, this reduced to 0.35 where the BK12 bearing sits. So I did what any self respecting person would do, put it in the vice and knocked seven bells of shite out of it ! to say I was upset would be an understatement. Actually I put it in my mini lathe chuck with a DTL fitted and 'coaxed' it back straight. It's a lot better but not perfect due to the off centre turned down section. Next I'll have to see what can be done with the Y ball screw. Who's idea was it to get stuff from China ?

Lee Roberts
11-03-2014, 09:56 PM
Who did you buy from ?

EddyCurrent
11-03-2014, 10:15 PM
Who did you buy from ?

I bought them from Chai

Jonathan
11-03-2014, 10:51 PM
Whilst we're close to the topic...for a while now I've been dismantling new ballnuts I've obtained from Chai, as it's not uncommon to find debris in them - be that just general dirt or bits of metal.

On the machines I've made to get zero backlash (lathe, mill & router), I preloaded the angular contact bearings using disc springs and shims between the bearings. That way there's less risk of damaging a bearing by over-tightening the nut as you know how much force you're applying from the spring deflection and it avoids buying matched bearing pairs. I also use bearings with a bigger outer diameter than the ones in the BK blocks - i.e. use 7201. They're less delicate...

If you want an easy option for a standard CNC router, then I don't see much wrong with just using double row angular contact bearings (52xx series), as although they have a small amount of axial play, the amount is much smaller than the single ballnut backlash so overall the effect isn't very significant. If you start pre-loading the nuts, then naturally the bearings need pre-loading too.

Also, be very careful with opening out the bearing blocks to better fit the bearings, as going too far may introduce backlash (depending on quite a few factors).

EddyCurrent
11-03-2014, 11:32 PM
Yes I think you are correct about the double row bearings, I was looking at those yesterday. Getting the nut set right on the BK type is a bit of a fiddle to say the least.

JAZZCNC
12-03-2014, 12:39 AM
You make me laugh you lot.!! . . . . Your quite happy to pay peanuts for the parts but then whinge and whine when they aren't top quality.!
WTF do you expect when You couldn't even buy one decent Angular contact bearing in this country for the price payed for both Blocks with bearings.

I strip, grease and shim every BK/BF bearing. It Takes minutes to do and other than that they are mostly fine considering the price payed.

Yes I could make my own better but unless chasing true Zero Backlash like Jonathan mentions then I'd just be wasting time and money because the BK/BF blocks when fettled work perfectly fine for any normal router machine.

EddyCurrent
12-03-2014, 09:13 AM
You make me laugh you lot.!! . . . . Your quite happy to pay peanuts for the parts but then whinge and whine when they aren't top quality.!


Totaly wrong, I don't expect top quality but I do expect 'fit for purpose'

JAZZCNC
12-03-2014, 09:31 AM
Totaly wrong, I don't expect top quality but I do expect 'fit for purpose'

I know what you mean but come on it's 10min job at tops and it's not difficult or hard. There has to be some affect of cheap prices and If folks have the abilty to build the machine in first place then in the grand scheme it's a drop in the ocean to fettle these bearings.

Getting all anal about bearing's and whether one came from China and other Japan is mostly pointless unless your chasing very tight tolorences because your own workman ship will introduce a lot more error than a couple of cheap or mismatched bearings ever will.!! . . . . . End of the day it's a router for cutting Wood and provided the bearings are greased and shimmed to remove lateral movement then they last for years.! . . . I've just after 5yrs changed my bearings, yes I've adjusted and greased them couple of times in that period but that's just normal service like any machine needs.

EddyCurrent
12-03-2014, 08:50 PM
Well, not even that, I just want to buy them and fit them knowing they will work as expected, is that asking too much ? I don't think so.

Anyway I stripped the Y axis ball screw out and laid it on a flat surface, sure enough it was bent about half way. Using a feeler gauge I slid it along underneath to find the bend position, then I put it in a vice with wooden jaws, put a pipe over the other bit and 'leaned' against it until it was straight. Now it's about right however the ball nut is a bit crunchy, I pumped some grease in and the metal particles that came out was alarming, it's still a bit rough and sticks now again so I see no alternative than to strip it out and clean, that's assuming it will go back together.

JAZZCNC
12-03-2014, 08:59 PM
Well, not even that, I just want to buy them and fit them knowing they will work as expected, is that asking too much ? I don't think so.

Well you need to dig deep then and pay the price.! . . . Can't expect to pay 15-20 for something that cost's 80-100 over here and not have something to complain about.!! . . . BUT I suspect we'll have to agree to disagree. :stupid:

EddyCurrent
17-03-2014, 11:51 AM
Been away for a few days, got back and now the PC graphics card has gone ! more expense.

Took the ball nut off like I mentioned earlier, emptied the contents into an old but clean washing up bowl I use for occasions like this.
The ball nut has 3 ball circuits and each ball measured about 3.15mm in diameter, maybe they are 1/8" inch ? anyway the number of balls that came out was 53 so right away you know there is something amiss. Before removing the ball nut the problem was that it felt like it was dragging and looking at grease patterns on the ball screw it looked like the centre ball circuit was stuck because the grease was being totally removed from the ball screw in those threads.

I watched this video on how to repack the ball nut and it was no problem putting it back together.
Linearmotionbearings C7 Ballnut Flipping and Repacking - YouTube (http://www.youtube.com/watch?v=5qbVrRYzK5U)

He explains in the video that 16 balls should be in each circuit which leaves a gap, I found that 17 balls left a similar gap so that's what I put back in and it's now nice and smooth running.

Edit: 10/12/2014 It was later confirmed that the correct number of balls for a 1605 or 1610 ball screw is 17 balls per circuit 51 total. (so that's good news for me !)

So the problem was too many balls in the ball nut so that they were jamming instead of rotating.

Wobblycogs
17-03-2014, 12:15 PM
No one wants jammy balls!

Interesting video, thanks for the link.

Neale
17-03-2014, 12:23 PM
Eddy - I'm looking to build a steel-framed machine and yours looks like a great candidate for stealing the design! I am looking for a slightly larger cutting area although I don't think enough to make any significant difference. Before I start, do you have thoughts on what you might do differently if you did it again?

EddyCurrent
17-03-2014, 09:51 PM
The only thing I would do different would be to make sure the ground was level that the welding was going to take place and I would not weld the 10mm plates to the bottom of the top beams because it warped them like a banana, I would bolt them to the beams instead with a thicker plate inside to beef up the 3mm wall thickness of the box section.

EddyCurrent
19-03-2014, 07:46 PM
I had to strip it down a bit today because there was still a BK and FK bearing to sort out, both had bearings in facing the same way and no grease, made shims, greased, reassembled.
More progress, ready to order some energy chain and start wiring and I'm very pleased the panel is already built.

11883

Limit and home switch for Z axis, there is one switch and two strikers. For the home switches I mounted a piece of 6mm thick mild steel to aluminium angle to act as the target.

11884

Motor mount for Y axis

11885

limit switch and adjustable striker for Y axis, there's another striker at the other end of the gantry, so one switch with two strikers.

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JAZZCNC
19-03-2014, 08:12 PM
Eddy I would move that bottom switch as the swarf and resin builds up very quick around the bottom of Z axis and you'll be cleaning it constantly.

EddyCurrent
19-03-2014, 08:18 PM
Eddy I would move that bottom switch as the swarf and resin builds up very quick around the bottom of Z axis and you'll be cleaning it constantly.

Noted, however I did have a struggle to find a better position for the switch so that it could be operated at both ends of the Z travel. If it becomes a problem in use I'll move it and remember I'm cutting wood.

JAZZCNC
19-03-2014, 08:50 PM
Noted, however I did have a struggle to find a better position for the switch so that it could be operated at both ends of the Z travel. If it becomes a problem in use I'll move it and remember I'm cutting wood.

Wood is even worse than Aluminium for sap and resin etc, honest you'll be surprised just how much it collects at the bottom of Z axis.
Also with Z axis why would you need a Limit on the down because often the bed is the limit and it just stops. Most Z axis only have limit switch at the top so put it at top.!

EddyCurrent
19-03-2014, 09:03 PM
Wood is even worse than Aluminium for sap and resin etc, honest you'll be surprised just how much it collects at the bottom of Z axis.
Also with Z axis why would you need a Limit on the down because often the bed is the limit and it just stops. Most Z axis only have limit switch at the top so put it at top.!

There's no sap or resin in any wood I cut but I'll see how it goes once cutting starts.
If there was no down limit the front plate would 1/2 leave one of the hiwin blocks before the ball nut hit the end, also I like the idea of a limit at each end.

EddyCurrent
22-03-2014, 09:02 PM
Thought I'd have a play with other stuff while waiting for the energy chain to arrive.
As I'm a hoarder I've had an old TV wall bracket in the attic for years, it can be extended out quite a long way and swivels side to side. As it is, the keyboard can be accessed easily from each side of the machine and from the front.
The wireless MPG has magnets built into the back allowing it to 'stick' to the panel.

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Wobblycogs
22-03-2014, 09:42 PM
Very nice set up Eddy. I assume the keyboard and monitor swing around to the side so you don't have to lean over the bed to get at them?

Looks like you are into woodwork as well, if I'm not mistaken that's a Jet 16" drum sander in the background. I'm planning on making a drum sander once the CNC (and workshop) is built. It'll probably turn out to be cheaper to buy one but where's the fun in that.

Lee Roberts
23-03-2014, 12:48 PM
Looking very smart Eddy !

EddyCurrent
24-03-2014, 07:09 PM
More playing about today, lashed some wires in for the two X axis stepper motors and got it moving, A is a slave off X
Settings as follows;

AM882 - microstep 8 giving 1600 steps/rev
Mach3 - steps per = 160 (using 10mm pitch ball screws), Velocity 10000 mm/min, Acceleration 3000 mm/sec.

Tried velocity up to 15000 but it stalled quite often, so the question is, how do these numbers sound ?

It's not clear how to set things like 'Kernel Speed' when using the Smooth Stepper, I set it to 35000 Hz anyway.

JAZZCNC
24-03-2014, 08:06 PM
It's not clear how to set things like 'Kernel Speed' when using the Smooth Stepper, I set it to 35000 Hz anyway.

Doesn't use Kernal Speed has that's for Parallel port but it's recommended to set it to default 25000Hz. What is the Freq in the SS plug-in.? This is the equivalent of the Kernal speed but you can go much higher. That said don't go too high and you won't need to go much higher than 128Khz.

Your accel is too high really at 3000 try 1500-2000, having Accel high will make for jurky movements and potential stalls or lost steps. You'll probably find you can go higher on Velocity without changing any thing other than lowering Accel.

To be honest thou 10mtr/min is fine for rapid speeds, 10mtr/min is 1000Rpm on 10mm pitch so going higher risks chance of missed steps from lower torque as motors reach the corner speed and gantry weight and inertia push the motors.!

In practice you'll rarely cut at those speeds so I wouldn't go chasing any more speed really.!! . . . .Your after smooth stable running.

EddyCurrent
24-03-2014, 08:40 PM
Smooth Stepper is set to 1MHz, the range of settings is 32kHz to 4MHz so I set it to upper mid range.
Acceleration is high only because I read somewhere to keep it in line with Velocity, I did have it at 1500 and noticed no difference so I've just set it back to that now.

JAZZCNC
24-03-2014, 08:55 PM
Smooth Stepper is set to 1MHz, the range of settings is 32kHz to 4MHz so I set it to upper mid range.
Acceleration is high only because I read somewhere to keep it in line with Velocity, I did have it at 1500 and noticed no difference so I've just set it back to that now.

No point having SS set that high because both the drives and the BOB can't work at that pulse rate so going higher than 256Khz is a waste and can potentialy cause problems or make system unstable. Personaly I would drop it back to 128Khz has you'll never need higher than that anyway.

EddyCurrent
24-03-2014, 09:03 PM
Very nice set up Eddy. I assume the keyboard and monitor swing around to the side so you don't have to lean over the bed to get at them?

Yes it does, it can swing out to either side


I'm planning on making a drum sander once the CNC (and workshop) is built. It'll probably turn out to be cheaper to buy one but where's the fun in that.

I keep an eye out here for customer returns Engineering Chuck Centre Chisel, Woodwork Woodturning Cutting Craft items in Axminster Tool Centre Devon Tools Power Provider store on eBay! (http://stores.ebay.co.uk/Axminster-Tool-Centre?_rdc=1)

Wobblycogs
24-03-2014, 09:19 PM
Yes, I've been known to have a look in that store from time to time. Got a rather nice P/T from it a few years back. I little bit of cosmetic damage saved me several hundred.

EddyCurrent
25-03-2014, 04:52 PM
I can't believe this Igus direct ordering, I order some energy chain (less than 3 metres) on Thursday 20th March and the estimate for delivery is Monday 31st March, so how does this video make sense ? I must have ordered part number 80,001


http://www.youtube.com/user/igusUK

m_c
25-03-2014, 05:13 PM
It happens.
They can't keep every possible item in stock, so sometimes you have to wait for it to be made and/or shipped across from Germany. If you're desperate for something, it's better to give them a call, as they can tell you exactly what they have in stock, and can suggest alternatives.

JAZZCNC
25-03-2014, 05:20 PM
I know what the problem is.?. . . . . .The stripes on there ties go in wrong direction. . Lol

On 21st I ordered some parts from China and the tracking number has them in Uk now and should be with me Thursday/fri. This order includes Energy chain Which IMO is every bit as good as Igus stuff but only costs me 18.50 for 2mtr.!!

Wobblycogs
25-03-2014, 05:28 PM
I'd not by items from Igus just because of those ties! I can't say fashion is high up on my list of "things wot I know something about" but even I could do better than that.

I completely agree though Jazz, as long as you're prepared to do your homework the stuff coming out of China is just as good as the locally sourced stuff at a fraction of the price and often with similar delivery times. I'm sure Igus are making plenty of money at the moment but I can't help feeling they (and a lot of European companies) are leaving the door open for far eastern companies to come over here and eat their lunch.

EddyCurrent
25-03-2014, 06:12 PM
I ordered it from Igus thinking it would be here next day or 2 days most, had I known earlier it would be like this then I'd probably have gone to China for it like you say.

Clive S
25-03-2014, 06:24 PM
I ordered it from Igus thinking it would be here next day or 2 days most, had I known earlier it would be like this then I'd probably have gone to China for it like you say.I bought two chains from them and they came next day, about one month later I had a visit from a rep and he left me with two books about 40mm thick and sample pieces of chain. ..Clive:glee:

EddyCurrent
25-03-2014, 06:35 PM
There was a time when I used to order hundreds of metres of great big chain and also their flexible cables but times and people(reps) change.

EddyCurrent
26-03-2014, 12:13 PM
Gave me time to get the fans fitted anyway, something I was not looking forward to but not as bad as I thought. I'll probably fit a thermostat with a remote sensor in the hood.
Two fans mainly because I already had them but they are 110 Volt so just wired them in series. Made a box with a sliding lid to allow easy replacement of filter medium, the fans are blowing into the panel pulling air through the filter medium. A vent at the top allows heat to escape by convection or forced by the fans, it does not allow crap to enter under gravity.
The wiring will have to be kept to the back of the panel as much as possible so as not to interfere with air flow.

(just ignore the temporary lashed in wiring)

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Wobblycogs
26-03-2014, 01:15 PM
I like that top vent, do you have a source for them?

I'm hoping they come in 80mm square versions. I currently have regular fan filters at the top to stop crud getting in but I think the air flow restriction they cause will be too great so a vent like that would be perfect. The alternative is to fit a couple more fans at the top but that then risks creating a negative pressure in the case.

EddyCurrent
26-03-2014, 01:36 PM
I like that top vent, do you have a source for them?

Home made from an old IKEA metal shelf, sometimes I don't mind a bit of sheet metal working, I was going to use the side cut from an old washing machine, another good source of sheet metal.
I drew it in Sketchup to get a template for cutting it out of a flat sheet.

JAZZCNC
29-03-2014, 02:21 PM
Eddy noticed you have wire tags or numbers on your wires where did you get those.? . . . I've looked around but can't find any at sensible money.

mekanik
29-03-2014, 02:37 PM
Got this type on ebay
Cable Tie Ident Nat 100mm Pk100 - Price For Pack Of 100 - MCV100 | eBay (http://www.ebay.co.uk/itm/Cable-Tie-Ident-Nat-100mm-Pk100-Price-For-Pack-Of-100-MCV100-/390769202889?pt=UK_Computing_Cable_Ties_Organisers&hash=item5afba8d6c9)

mekanik
29-03-2014, 02:55 PM
Hellermann H050 Yellow Letter Cable marker, Wire Ident, Wire Marker bag 1000 TWL | eBay (http://www.ebay.co.uk/itm/Hellermann-H050-Yellow-Letter-Cable-marker-Wire-Ident-Wire-Marker-bag-1000-TWL-/190967860179?pt=UK_BOI_Electrical_Components_Suppl ies_ET&var=&hash=item2c76924bd3)

JAZZCNC
29-03-2014, 03:26 PM
Hellermann H050 Yellow Letter Cable marker, Wire Ident, Wire Marker bag 1000 TWL | eBay (http://www.ebay.co.uk/itm/Hellermann-H050-Yellow-Letter-Cable-marker-Wire-Ident-Wire-Marker-bag-1000-TWL-/190967860179?pt=UK_BOI_Electrical_Components_Suppl ies_ET&var=&hash=item2c76924bd3)

Cheers but they only sell letters and I want letters and numbers.