Comments sought on new build: A CNC Router for RC Gliders and Planes

I agree with JazzCNC - loading the stepper motor bearings so much wont end well...

I lay awake thinking about that last night and came to the conclusion that I was kidding myself it would be ok and should have known better....I'll pocket it deeper and tension the belt from the side....or weld up a bracket from steel that can slide to tension it. Cheers chaps.

A bracket could be made to fit in between the top and bottom plates projecting back and lapping around the back face of the two plates ( like a tee piece) it would mean the motor is sticking out the back slightly.
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"TOOMAST ..Do you have special machining on ballscrew? I notice longer area for the pulley?" Just order the ball screw with the "F" measurement 30mm instead of standard 15mm. ..Clive

Clive I'm going to pocket out the bracket that I've got and use that with a shorter belt I think....well that's the current plan anyway!

Quick play on the milling machine...

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A few bits for my PSU came today....just need some choc block connectors and some fuses and ill be away...

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Ok so pulled the gantry apart and machined the front and bottom plates (M8 counterbored hole in each)

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Put it all back together and it's nice and solid...

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Control cabinet and bits arrived just now so more stuff to play with [emoji3]

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Going over to Wobblycogs tonight to have a catch up, talk CNC Routers and look at his control cabinet to get some inspiration...

OK quick question. I'm now coming to the end of the mechanical build so my mind's turning to all things electrical :cower:

When connecting the CY cable to the stepper how do you folks do it? I was thinking of either via a chocolate block as near to the stepper as possible or probably I'll go with soldering the wires with heat shrink over them and then heatshrink over the whole lot?

I'd expect soldering+heatshrink to be the most reliable way to do it.

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Originally Posted by Jonathan

I'd expect soldering+heatshrink to be the most reliable way to do it.

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Agreed it's the most hassle free way I find.!

Cheers, just thought that as long as the joins soldered ok then there's no potential at the join for a loose connection.

Next question! I'm going to get a safety relay (probably a second hand Pilz from ebay) for estops, limits, home switches etc. What's a good model to get, I've seen some Pilz PNOZ X3's which seem to fit the bill?

I went with a small project box over the area on the stepper motor where the wires exit, making it look a bit tidier. Also adds a bit of impact protection. Inside the box I used a choc-box.

Attachment 14851

But solder and heatshrink, with the option of netted sleeving also work.

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Originally Posted by njhussey

Cheers, just thought that as long as the joins soldered ok then there's no potential at the join for a loose connection.

Next question! I'm going to get a safety relay (probably a second hand Pilz from ebay) for estops, limits, home switches etc. What's a good model to get, I've seen some Pilz PNOZ X3's which seem to fit the bill?

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I'm not going to talk you out of a Pilz style relay as I looked at those as well and was impressed. However, I will mention that a level of safety interlock can be achieved with a cheap multi (4) pole relay - mine was about £8 and has the option of DIN mounting:
Attachment 14852

One of the poles can be used to form the latch, and the rest are free to switch whatever you need downstream. However, if you don't mind the expense then the Pilz system is neat is and is what the industry seem to use.

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Originally Posted by routercnc

I'm not going to talk you out of a Pilz style relay as I looked at those as well and was impressed. However, I will mention that a level of safety interlock can be achieved with a cheap multi (4) pole relay - mine was about £8 and has the option of DIN mounting:
Attachment 14852

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I agree pilz are nice to have but not really required at DIY level. Normal relays work just as well provided they are correctly sized.

As stated a latching circuit is easily created and standard 24Vdc relays are cheap and easily sourced for any future problems. Depending on level of safety you'll still probably need a plan vanilla relay or 2 anyway as the pilz won't provide enough contacts.!

I'll also add that all the really cheap Pilz relays I found on ebay were 'spares or repair' so read the advert carefully if you go that route.

This is now not a plain DIY router but will be at work so I'm going to try and be as safety concious as possible. I'll come up with the number of relays ill need and then see which way to go.

I got the 625VA transformer, will it be beneficial to build a soft start? From reading and talking to Wobblycogs it's right on the edge of needing one. I well oversized it as I left the 6A in the equation by mistake for the Nema 34 motor that's being powered by a 240V drive!!

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Originally Posted by routercnc

I went with a small project box over the area on the stepper motor where the wires exit, making it look a bit tidier. Also adds a bit of impact protection. Inside the box I used a choc-box.

Attachment 14851

But solder and heatshrink, with the option of netted sleeving also work.

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The Z axis stepper will be covered by a cover ill be making from sheet metal to cover the entire Z axis (Jazz's idea) and the Y stepper is enclosed in the gantry (or will be) so the only stepper exposed will be the X axis one, I might look into a cover for that once the machine is up and running. It'll also be tucked away at the top of the router (it's going 80° vertical on its side) at the back so hopefully out of the way.

[QUOTE=njhussey;67784 This is now not a plain DIY router but will be at work so I'm going to try and be as safety concious as possible. I'll come up with the number of relays ill need and then see which way to go.]

Very good point - I was stuck in the DIY mindset but that's not where you are with this build. This is a machine for use at work, possibly by others, so that puts things in a different light. I know this has been debated numerous times on the forum but yes in this case I'd be following industry standards so carry on !

I've got a load of new old stock of screened 8, 6 and 4 core alarm cable if anyone needs any, it's worth about £15 a drum on the bay but I can't be asked with that, happy to help anyone out if they would like some.

Should be good for limits and so on?

I've also got a big drum of cable brading as well.

.Me

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Originally Posted by Lee Roberts

I've got a load of new old stock of screened 8, 6 and 4 core alarm cable if anyone needs any, it's worth about £15 a drum on the bay but I can't be asked with that, happy to help anyone out if they would like some.

Should be good for limits and so on?

I've also got a big drum of cable brading as well.

.Me

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Thanks for the offer Lee, I've got about 40m each of 0.75mm^2 and 1.5mm^2 CY and a roll of 1mm^2 Tri rated cable of earth red and black so hope I'm going to be ok [emoji2]

Np's offer is there for everyone, ive got about 10 full rolls and a few ive used so happy to get rid by the meter if anyone wants it.

£5 A Roll + the postage, so prob end up being around half price, 15p a meter if you just want a cut lenth...

Sorry to go off topic just trying to help if I can, build is looking "sweet-as-a-nut!" xx

.Me

No probs and cheers Lee....

I'm just reading up on safety strategys so I can see how many relay connections I need etc. Struggling to get my head round it, think I need to lock myself away from all distractions to get my head round it :stupid:

OK another question, I presume the proxy switches to get are PNP NC ones (sods law as I have a good selection of used and new NPN NO ones that somehow didn't get left behind at my previous job!!)

If you haven't purchased your cable yet you might look at IGUS. They are a bit more but the difference in ease of flex and movement makes wiring up and setting up cable trays and runs so much easier. That is just my experience in helping a few folks rebuild older machines. I am seriously tempted to redo mine do to how much it makes getting a good clean cable run done. I don't own stock nor get a discount or anything just very happy with the product.

Michael

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Originally Posted by m.marino

If you haven't purchased your cable yet you might look at IGUS. They are a bit more but the difference in ease of flex and movement makes wiring up and setting up cable trays and runs so much easier. That is just my experience in helping a few folks rebuild older machines. I am seriously tempted to redo mine do to how much it makes getting a good clean cable run done. I don't own stock nor get a discount or anything just very happy with the product.

Michael

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Hi Michael, I've already got the cable ta (which does seem quite flexible, but I've nothing to compare it with!) but if I have any problems with the cable runs I'll give IGUS a look cheers.

OK so once again work got in the way of progress.....however I managed to get an hour on it this afternoon just. I've made a "rough" X Axis stepper support plate and put it on the frame. Don't worry there will be plenty more bolts holding it on than are currently there!! One thing I've found is that my frame is not as square as I'd like, comes of rushing it to get it done before I lost the workshop at my old firm.

I've also added a couple of skate bearing idlers, these are temporary until I make proper shiney aluminium brackets as they're quite bendy! The plate will also eventually be either replaced or tidied up to make it look nicer as it looks really rough and ready and spoils the look of the build. However for the purpose of getting the mechanical build finished it'll do temporarily.

Attachment 14863

Attachment 14864

Been thinking about where to put the router and will be putting it an 80° angle mounted in a frame. As it's in a work environment I'll be building a frame that can be sheeted and have interlocked doors on it......something along the lines of the below:

Attachment 14891

Attachment 14892

This will have the added bonus of stopping the chips being flung everywhere, there will be a bin under the router to collect the swarf which will be slid out the front to empty it. I'll mount the router on the frame using epoxy putty pads where it's going to be bolted so the bolting doesn't induce any twisting in the router frame.

Have you thought about mounting it the other way so the X screws would be hanging down with the gantry horizontal.
It just seems to me quite high to reach and all the chip will fall on to the bottom screw. It is not going to need a big box to hold the chips. ..Clive

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Originally Posted by Clive S

Have you thought about mounting it the other way so the X screws would be hanging down with the gantry horizontal.
It just seems to me quite high to reach and all the chip will fall on to the bottom screw. It is not going to need a big box to hold the chips. ..Clive

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Yeah that's how I was originally going to have it but I thought with space now not being an issue I could have it round the other way which means that it's easier to load the work (top of bed is 1.75m, eye height, from floor, bottom is 1m from floor), not so much bending. I'll put a deflector on the bottom beam (and top) to deflect the chips away from the rail and ballscrew.

Attachment 14893

Ok so I got my spindle mount today....

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20 mins later...

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Just need to drill and tap the front plate this afternoon. Spindle should be delivered tomorrow or Thursday...

Had my cable markers delivered, should have enough here for a few control panels! Got 0 to 9 and E, N, L, X, Y & Z.

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Originally Posted by njhussey

Yeah that's how I was originally going to have it but I thought with space now not being an issue I could have it round the other way which means that it's easier to load the work (top of bed is 1.75m, eye height, from floor, bottom is 1m from floor), not so much bending. I'll put a deflector on the bottom beam (and top) to deflect the chips away from the rail and ballscrew.

Attachment 14893

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Neil you'll need much more deflection than that.!! . . . . I had my old machine vertical in both positions and the other way is much better for access and chip clearing.

The way you have it will need much more protection for the screws, both lower and upper. Just remember chips go up then back down again so they will settel on the top rail and screw.

I'd also urge you to cover the Z axis, to be honest I do this on all my machines now as it keeps a lot of crap out the works, but it's Esp important on vertical machine either way up as the dust settles either on the backside or onto rails etc.

Which way is best.? . . . .Well let me just say my new machine is going on wall when get chance and it will be other way to what you have.!!

Where did you get those markers.?

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Where did you get those markers.?

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According the name on the real you should be able to get them http://www.edmundson-electrical.co.uk/

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Originally Posted by JAZZCNC

Neil you'll need much more deflection than that.!! . . . . I had my old machine vertical in both positions and the other way is much better for access and chip clearing.

The way you have it will need much more protection for the screws, both lower and upper. Just remember chips go up then back down again so they will settel on the top rail and screw.

I'd also urge you to cover the Z axis, to be honest I do this on all my machines now as it keeps a lot of crap out the works, but it's Esp important on vertical machine either way up as the dust settles either on the backside or onto rails etc.

Which way is best.? . . . .Well let me just say my new machine is going on wall when get chance and it will be other way to what you have.!!

Where did you get those markers.?

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Ok I'm sold, if both you and Clive say it's better the other way ill put it back how I was originally going to have it!!

I am going to make a cover for the Z axis (just not shown it here) and the back of the Y axis will be covered with an Ali or perspex plate and chip deflectors put on to protect Y axis rails. The X axis belt will be covered. I'll be putting sides on the machine from the X axis rails down to the bed and also at the back to stop chips from flying too far round the enclosure.

I got the markers from Worcester Electrical (WED), not the cheapest I'm sure...

Running out of mechanical things to do now so suppose I'd best stop fannying around and do the electronics.....

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Originally Posted by njhussey

Ok I'm sold, if both you and Clive say it's better the other way ill put it back how I was originally going to have it!!

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Only thing better is chip control other than that there's very little difference, If want to be Knit picky then could say your original way will give slightly faster rapids but in practise this doesn't matter as it will be more than fast enough.
One thing I will advise is building in some Bump stops at the bottom and when not using for extended periods Park it onto the bumps. This takes strain off the ballnuts and bearings.
I use Gerry's 2010 Screen set which as a PARK position so used this to lightly bump upto stops when finished at end of each day. In use I used the TC(tool change) option to send Gantry to top of machine for loading material tools etc.

You won't regret going vertical. To fully appreciate the difference use the machine in traditional Horizontal position before going vertical.!! . . . Before I retired my old machine it was horizontal for few agonising and messy months. It's replacement as been working for only a few weeks and already the chips flying around shop are driving me crazy, and that's not to mention the room it's taking up.!!

I've got some hard stops at the bottom end and will be putting some rubber for the gantry to rest against as you suggested this when I first mentioned going vertical. I'll use it horizontally until I've built the frame but it'll have to be on the floor as the tables aren't strong enough to not be shaken to bits with it on running at full chat....

Today is re-designing the moutning frame/enclosure.....

Attachment 14913

Had a delivery today, scrapping my original home made spindle design for a "standard" 2.2kW one...

Attachment 14915

Slight bit of damage where it looks like it was dropped, nothing serious just cosmetic and nothing that can't be sorted with a file! Spindle spins freely and smoothly...

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Currently looking at positions for the limit and home switches...

Started the PSU this afternoon, got to fix the rectifier (need some thermal paste yet) and then decide how I'm going to do the fuses...

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Ok so done the PSU. One thing I'm not certain on is the rectifier wiring. Can you electrically minded people have a look and make sure I've got the connections correct, I think I have but would like confirmation...Thanks!

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Looks right to me ?

Neil

I would not be happy with the choc block you need some sort of insulation under it as any stray wires could short to the chassis. Also a larger choc bloc might be better as you are daisy chaining the power from one to another. It would be nice to have a separate wire to each from the main. Just my two cents worth. ..Clive

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Originally Posted by Clive S

as you are daisy chaining the power from one to another. It would be nice to have a separate wire to each from the main. Just my two cents worth. ..Clive

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At first glance I thought that, but he's using such excessively thick wire that it's probably not a big deal.

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Originally Posted by Clive S

Neil

I would not be happy with the choc block you need some sort of insulation under it as any stray wires could short to the chassis. Also a larger choc bloc might be better as you are daisy chaining the power from one to another. It would be nice to have a separate wire to each from the main. Just my two cents worth. ..Clive

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I tinned the wires (and soldered them together) daisy chaining the power in the choc block which is 15A rated so I thought was big enough? I'll put some form of insulation under it if you think it's needed? How would you do a seperate wire to each from the main?