Aluminium Profile Type Router - Initial questions [Archive]

CNCRY

05-02-2020, 12:12 AM

Hi Everyone,

First post on this forum and CNC in general. There seems to be a huge amount of knowledge on this forum, and I feel very out of my depth but learnt a lot lurking here for the past couple of weeks, from a base of zero !
Not sure if I should be creating my own build log as its just a couple questions for now.
So I'm looking at building a CNC router for perhaps 75% soft/hard wood, 25% aluminium use. I mainly work with wood on a hobby level.
I don't have any CAD drawings etc yet, all just paper! sketches but the plan is in the style of the 3d tek heavy mill with some inspiration from here.
wasteboard size 1080 x 1000mm

Here are the parts I'm planning to use this far;

Hiwin 20mm Linear Rails/ HGW20CA Carriages @ 900mm (for X & Y Axes)
2005 Ball Screws @ 900mm for X and Y ( 2 on Y axis rails)
BF15/BK15 Mounts
1605 Ball Screw for Z Axis
Z Axis TBC, but likely SC16LUU type bearings
4 x Nema 23 4NM stepper motors

Purchased so far: Aluminium Profile
2 pieces of 40 x 120 @ 1000mm (Y axis)
4 pieces of 40 x 40 @ 1000mm (X axis supports)
1 pieces 80 x 80 @ 1200mm for X Gantry (will rest on aluminium plate on linear rails)

Parts which I need some assistance with (so far...)
I have minimal electrical experience this far, aside from domestic 240V type.
So looking for comments on the below - will it work together etc. I'll probably not purchase any of the below until physical build well under way but getting an idea of design and cost.

Laptop with Ethernet..
AXXB-E Control board - I like this as it works with UCCNC and Mach3/4, plus doesn't require a breakout board I believe. Does anyone have good/bad experience with this?
Stepper Drivers - Would something like CW8060 from cnc 4 you deliver good performance from the motors? Anything better at similar price point? Stall detection sounds like a must but not clear if this has it?
Power Supply - What Voltage to drive the motors at for optimum performance? and any PSU recommended?

Thanks!

AndyUK

05-02-2020, 08:54 AM

Hi CNCRY,

Welcome to the forum!

Usual advice is to hold off on further purchases until you've got the design finalised and pretty confident about each electronic component - changes upstream can irritatingly change what you need on the mechanicals, and electronics have a way of updating while you're building, so best to buy once when you need it rather than in advance, so you've got the right idea there.

I suggest you read through the build log section of the forum; you should be able to look at the 3D Tek design and notice where they've done the right thing and where they've skimped. You've already identified that ballscrews are a more appropriate drive option for example - but there are a few design choices about the Z axis that I wouldn't emulate.

Regards your rails and screws choice, the rails seem appropriate, the screws are about right, but in this size I'd also consider 16mm screws and 10mm pitch options, but all depends on if you want to use pulleys. There are a few calculations you can do to help you determine whats best for your use, but you'll pick this up in the build logs.

You're correct that the AXBB-E has a breakout board built in and seems to get a good rep (I haven't got one!), but also compare against other options such as built-in controllers and say UC400eth with a cheap breakout or expensive breakout. Generally I'd say stick with Ethernet based controllers, unless you're going down the LinuxCNC route.

Voltage and PSU specs are again very common topics in the build logs so I won't delve into it here (but bookmark threads and page numbers when you find these things!!). Generally unregulated PSUs are preferred, a lot of users build their own, or purchase AC drives so you only need a toroidal.

Hope that helps!

Clive S

05-02-2020, 09:01 AM

Generally I'd say stick with Ethernet based controllers, unless you're going down the LinuxCNC route.
Would you mind expanding on this?

There are plenty of cards for linuxcnc ie .Mesa 7i92,7i96,7i95 ,7i76e .

AndyUK

05-02-2020, 09:09 AM

Would you mind expanding on this?

Hah! Yes, "Unless you're going down the linuxCNC route in which case I have no idea" :P

Reading it back it sounds like I'm saying don't use ethernet with LinuxCNC - it was meant as an "if you're using LinuxCNC there may be more appropriate options like onboard PCI cards".

CNCRY

05-02-2020, 09:51 PM

Thanks Andy,

I'm trying to figure out whether 2005 or or 2010 ballscrew would be better, or 1605/1610 (which seems to be less available pre machined). I don't plan to use pulleys.
Problem is all calculations seems to lead to other values which I don't know what I'm aiming for!
So filling out a speeds and feed calc for say hardwood @ 20,000rpm spindle I get min/max of 9-11 M/min speed. Assume this is the cutting speed and the rapid people refer to are movement between cuts.
I also used zapp calculator to get critical speed of 20mm diameter ballscrew with 750mm spacing between supports giving 1548 RPM.
From forums someone gives 2010 screw @ 1348 RPM = 2.15m/min, so would the motor need to at appox 6740rpm to achieve that?
But also the motor Voltage driven needs to be known to get an idea of rpm which can be achieved?
I also don't know the final weight of the gantry, I'd estimate say 20Kg based on extrusion weight + spindle and alum plate.

On another note - have I already got off to a bad start using the non-heavy type of aluminium profile. This was from KJN, I intend to add plate/strengthening to make it more rigid.
Just installed fusion 360 to see if I can learn to create my design in diagram form:)

Ryan

AndyUK

05-02-2020, 10:13 PM

I'm trying to figure out whether 2005 or or 2010 ballscrew would be better, or 1605/1610 (which seems to be less available pre machined). I don't plan to use pulleys.

Meh, get a custom quote from Fred and he'll machine whatever you want, it'll still probably be cheaper than the pre-machined, and you'll have a quality product from a trusted vendor.

So filling out a speeds and feed calc for say hardwood @ 20,000rpm spindle I get min/max of 9-11 M/min speed. Assume this is the cutting speed and the rapid people refer to are movement between cuts.

Yep. No feeds and speeds calculator will ever give you rapid speed recommendations. Do remember that it will also depend on how many flutes your cutter has.

From forums someone gives 2010 screw @ 1348 RPM = 2.15m/min, so would the motor need to at appox 6740rpm to achieve that?

Then that someone is a tit and can't do maths. It was probably me. The 2010 means that the outside diameter of the screw is 20mm, and the pitch is 10mm. In one turn of the screw, the ballnut will move 10mm. So 1348 turns per minute equals 13480mm/min = 13.48m/min.

But also the motor Voltage driven needs to be known to get an idea of rpm which can be achieved?

Its less about the voltage, more about how much torque you have left when you get up to those RPMs, which then dictates how quickly you can accelerate and decelerate. Whilst I spent a lot of time doing the calculations, I still ended up with the same motors as everyone else with the machine size, so for starters find a decent build about the same size and steal their motor and PSU configuration :P Work forwards from that.

I also don't know the final weight of the gantry, I'd estimate say 20Kg based on extrusion weight + spindle and alum plate.

Quite machine dependent, but I'd guess you're lowballing it. A 2.2kW Spindle is approx 8kg alone. Rails + Ballscrews + Plates + Motors + Extrusion should be a good ballpark. Maybe nearer 30-40kg?

JAZZCNC

05-02-2020, 11:14 PM

CNCRY

05-02-2020, 11:57 PM

Thanks for bearing with me, now I have the whole idea in my head I'm keen to start building , but want to do it right first time so remaining patient, and re-thinking the design.
Is Fred the BST automation aliexpress store? What sort of lead time do people get with him and is there a ballpark % amount of import duty etc to be expected?
That RPM calculation was from a U.S forum in IPM, and was clearly wrong then. Thats clear now, so with the 10mm pitch I'd need to aim for 1000rpm to get 10m/s cutting speed, which should be about right for a 2 flute cutter in hardwood. While Aluminium would need to aim for 5m/s or 500rpm at the motor?
So from most similar builds I have seen everyone ends up with 3/4NM Nema 34 motors, but there is variation in how they can be driven.
Trying to pin down some aspects so I can then design around those.
You are right on gantry weight . Profile is 8kg + 8Kg spindle + perhaps 10kg rails and carriages + aluminium plate + motor - more like 35Kg.
Ryan

CNCRY

06-02-2020, 12:21 AM

Hi Ryan,

Let me just say from the start that the Heavy Mill 3DTEK as got some serious issues and it's far from its name suggests.

First off scrap the Z-axis altogether it's load of rubbish and far too flimsy. The Z-axis is THE most important part of the machine because it's where all the action happens. If it's weak then it doesn't matter if the rest of the machine is built like a tank your cutting will always suffer.
Also, no point using Hi-win profiled linear rails on other axis if going to use a round rail on Z-axis, use either all-round or all profiled. You are wasting your money mixing them.

Next is the Gantry sides, they are also weak and flimsy. They will resonate and flex which again transfers into the cut. To be honest the whole gantry is on the weak side and could easily be made stronger with a design change. Even the Light profile will work if you used an L shaped design.

Regards the ball-screws you will be better with 16mm x 10mm pitch for a wood router at this size. 10mm pitch will easily allow you to cut aluminum without any problems. Whereas 5mm would be too slow for cutting wood correctly.
You don't need 20mm for a machine this size and it will only rob you of power and speed because of the extra inertia of the ball-screw. It takes more power to accelerate and deaccelerate than 16mm and it does make a big difference to performance.

Regards the electrics and controller then always go with Ethernet if you can afford the extra, it's much more stable than USB or parallel port.

Andy mentions Voltage isn't so important but I'm afraid he's wrong, It's very important to the speed and torque you'll get from a stepper motor. The torque you get from a motor is proportional to voltage so if you increase the voltage the torque will also rise, up to a point. To get high speeds from a stepper you need voltage which is why we try to use higher voltage drives so we can boost voltage. Obviously there is a limit dependant on motor/drive specs etc but in general, more volts = higher rpm which is better for a router.

Regards the Motor, drives and PSU spec then there is a well-proven spec for machines this size which has been used for a long time on this forum. Which I'm happy to help you with. However, I'd also advise you to consider looking at Closed-loop steppers as they have come down in price quite a lot and are much better than the standard stepper systems. This could change things a little regards PSU etc depending on which you go for. So go have a look at them if you haven't already and let us know your thinking.?

BIGGEST ADVISE is don't buy anything else until your 100% sure it's correct. Also don't buy electrics until needed as your wasting warranty and things change fast these days regards controllers/software and drives you could end up with a better system by waiting until needed.

Don't be afraid to ask questions no matter how dumb you may think they sound.

Appreciate the advice JazzCNC
Heavy Mill was my initial idea as I could see how it was constructed, plus I assumed must be a sufficiently good design to sell:) I'll not be copying it's Z axis in that case, and will design on the same rail setup instead. As I just mentioned in reply to Andy - im's trying to establish some "fixed" ideas and design around that, but X changes so does Y!
So one thing I did notice on heavy mill were weak side's so my design there is similar to Andys log = http://www.mycncuk.com/attachment.php?attachmentid=26713&d=1573338796 . That is rails on top on the extrusion, then a carriage and aluminium block which the gantry rail site on top of,and fixed using side plates .

I'll be looking into 1610 ballscrew based on both the replys now.
Do closed loop steppers work with standard nema motors ? I'll take a look.

I'll be trying to draw this in a shareable format soon. But design steps wise, can I design/build the X/Y axis and gantry to a good standard, then consider the Z axis as the next "module" or is that a bad idea!
If I know the motors to be used, I can pretty much leave electronics until the build progresses, and certainly won't buy anything related to that yet.
Will my existing 120 x 40 profile with 40x40 cross pieces suffice for X/Y axis with extra bracing?
And with the L design for gantry - just thinking how I can incorporate the 90x90 profile, perhaps a 60x60 attached to it at the back?

Ryan

Kitwn

06-02-2020, 02:44 AM

Is Fred the BST automation aliexpress store? What sort of lead time do people get with him.
Ryan

Ryan,
Yes, Fred is BST Automation. I fell of the sofa when my leadscrews and rails arrived in remote western Australia only 4 days after I paid for them. It often takes longer than that to get stuff from the state capitol Perth. You do pay quite a lot for delivery though and it's worth checking the different total cost for item + postage and 'free' postage for the same thing.

Don't forget that many Chinese businesses are closed at present because of the virus so delivery times at the moment are anybody's guess.

I don't know about import duties to Pommieland but make sure you know the total cost before comparing suppliers.

JAZZCNC

06-02-2020, 02:30 PM

So one thing I did notice on heavy mill were weak side's so my design there is similar to Andys log = http://www.mycncuk.com/attachment.php?attachmentid=26713&d=1573338796 . That is rails on top on the extrusion, then a carriage and aluminum block which the gantry rail site on top of,and fixed using side plates .

Yes, this is the L design I was suggesting, most of the L designs you'll see are based off my original design or someone else's who took from mine, it can be used both with or without Gantry sides and makes for a very stiff gantry with easy rail mounting etc. When mounting directly to the bearings just bear in mind access to the bearings bolts when deciding the bearing plate length. I've seen several designs that missed this little detail, which is why it's a good idea to draw it in cad to catch these things.

Do closed loop steppers work with standard nema motors ? I'll take a look.

No closed loop steppers have an encoder on the back which goes to the matching drives. Also often closed loop steppers are 3 phase steppers with smaller step angle of 0.9 or 1.2 deg whereas typical stepper is 2 phase. with 1,8deg step. The difference being closed-loop are smoother.

I'll be trying to draw this in a shareable format soon. But design steps wise, can I design/build the X/Y axis and gantry to a good standard, then consider the Z axis as the next "module" or is that a bad idea!

Yes you can but I wouldn't recommended it because your better designing the whole thing in CAD to see if anything clashes.

If I know the motors to be used, I can pretty much leave electronics until the build progresses, and certainly won't buy anything related to that yet.

All you really need to know is the motor frame size ie: NEMA 23 or 34. Now I've seen you mention Nema 34 is what you need.! This would be bad for a machine this size and mistake often made by new builders are thinking bigger is better, it's not.!
NEMA 34 motors require a much higher voltage to get the RPM needed for a router. A 4Nm NEMA 23 will perform much better than a 4Nm Nema 34 at the same voltage.

Will my existing 120 x 40 profile with 40x40 cross pieces suffice for X/Y axis with extra bracing?
And with the L design for gantry - just thinking how I can incorporate the 90x90 profile, perhaps a 60x60 attached to it at the back?

Yes, the 120x40 and 40x40 could be used for the frame with bracing.
Regards the Gantry then Bolting 60x60 onto the back won't do anything other than add weight. To get the stiffness and height you need one piece flat with the other bolted on top. So either buy a wider piece for the bottom and put the 90x90 on top or start again with 2 x 45 x 90.
I'm assuming that your using BR range profile because of the 90mm. This is good because when using 16mm screws then the BK End bearings mounting holes will line up with the 45mm slot spacing. If you used the IR with 40mm slot spacing then you would have to make plates or drill the profiles to bolt the bearings on.

It's these little things that catch you out and cause more work. Hence why drawing in CAD can save many wasted days and money.

CNCRY

07-02-2020, 01:40 AM

Yes, this is the L design I was suggesting, most of the L designs you'll see are based off my original design or someone else's who took from mine, it can be used both with or without Gantry sides and makes for a very stiff gantry with easy rail mounting etc. When mounting directly to the bearings just bear in mind access to the bearings bolts when deciding the bearing plate length. I've seen several designs that missed this little detail, which is why it's a good idea to draw it in cad to catch these things.

No closed loop steppers have an encoder on the back which goes to the matching drives. Also often closed loop steppers are 3 phase steppers with smaller step angle of 0.9 or 1.2 deg whereas typical stepper is 2 phase. with 1,8deg step. The difference being closed-loop are smoother.

Yes you can but I wouldn't recommended it because your better designing the whole thing in CAD to see if anything clashes.

All you really need to know is the motor frame size ie: NEMA 23 or 34. Now I've seen you mention Nema 34 is what you need.! This would be bad for a machine this size and mistake often made by new builders are thinking bigger is better, it's not.!
NEMA 34 motors require a much higher voltage to get the RPM needed for a router. A 4Nm NEMA 23 will perform much better than a 4Nm Nema 34 at the same voltage.

Yes, the 120x40 and 40x40 could be used for the frame with bracing.
Regards the Gantry then Bolting 60x60 onto the back won't do anything other than add weight. To get the stiffness and height you need one piece flat with the other bolted on top. So either buy a wider piece for the bottom and put the 90x90 on top or start again with 2 x 45 x 90.
I'm assuming that your using BR range profile because of the 90mm. This is good because when using 16mm screws then the BK End bearings mounting holes will line up with the 45mm slot spacing. If you used the IR with 40mm slot spacing then you would have to make plates or drill the profiles to bolt the bearings on.

It's these little things that catch you out and cause more work. Hence why drawing in CAD can save many wasted days and money.

Thanks Jazz - going to spend the next week or so learning fusion 360 and actually drawing the thing:) Probably makes sense to learn to use CAD alongside building a CNC machine!
The Nema motor - that was me being a muppet. I do mean Nema 23 4NM.
I guess the hybrid steppers are perhaps £50 more each with a driver package then a normal stepper and decent driver, something like https://www.cnc4you.co.uk/Stepper-Motor/Stepper-Servo-Motors/Stepper-Servo-Kit-4Nm. ?

RE: the profile, I spent a fair amount so far so would really want to avoid wasting . You are right its the BR as below with 45mm spacing, so will make mounting easier.

27327

So do you mean
40x120L along the bottom with 90x90 on top. Notice the slot spacing on that is 40 so no way to direct join - but I guess joining plates at ends will do?

27328

for BST automation shop, which as mentioned is probably not sending anything right now - something like
3 X Anti Backlash Ballscrew RM1610 -L1000mm with SFU1610 Ballnut + BK12 BF12 Support Unit + 1610 Nut Bracket + 6.35*10mm coupler shows as $141 + $107 shipping. $248 total. I've never order anything over a few £ from china - what import duty do people get hit with? Looks like VAT+2.5%?

Ryan

AndyUK

07-02-2020, 09:03 AM

For BST automation shop, which as mentioned is probably not sending anything right now - something like
3 X Anti Backlash Ballscrew RM1610 -L1000mm with SFU1610 Ballnut + BK12 BF12 Support Unit + 1610 Nut Bracket + 6.35*10mm coupler shows as $141 + $107 shipping. $248 total. I've never order anything over a few £ from china - what import duty do people get hit with? Looks like VAT+2.5%?

When you're ready, email them for a quote with exact sizes.

I was also concerned about ordering from BST initially, but there are a lot of examples of people here using them. Jazz probably keeps them in business singlehandedly. You can pay with PayPal via AliExpress. AliExpress hold the PayPal payment in escrow until the package arrives and then you release it to the seller. You're also doubley protected by PayPal, and even further if you use a credit card, so it's really no risk at all.

I paid roughly £1100 delivered including all import duty for four ballscrews (30cm 1605, 1m 1610 and two 1m 2010s) with associated ballnuts, ballnut mounts, BK and BF bearings (upgraded to AC I think), all custom machined to my exact lengths and to allow pulleys, all of my hiwin 20mm linear rail (2x1.2m, 2x1m and 2x35cm) and 12 hiwin carriages, and a 2.2kW spindle plus VFD with collets and water pump and spindle mount.

Sounds like a lot of money, but those three things were the most expensive components and about 1/3rd of the total build cost.

I won't go into further detail about the import duty, but trust me don't be concerned. You'll get a text or email when the parcel arrives in the UK and you just pay online.

NeoMorph

08-02-2020, 04:00 AM

For ref, AliExpress extended their new year holiday until February 18th.

See here for more information...

https://aliexpressblog.com/how-aliexpress-works-during-the-coronavirus-outbreak/

CNCRY

09-02-2020, 10:42 PM

When you're ready, email them for a quote with exact sizes.

I was also concerned about ordering from BST initially, but there are a lot of examples of people here using them. Jazz probably keeps them in business singlehandedly. You can pay with PayPal via AliExpress. AliExpress hold the PayPal payment in escrow until the package arrives and then you release it to the seller. You're also doubley protected by PayPal, and even further if you use a credit card, so it's really no risk at all.

I paid roughly £1100 delivered including all import duty for four ballscrews (30cm 1605, 1m 1610 and two 1m 2010s) with associated ballnuts, ballnut mounts, BK and BF bearings (upgraded to AC I think), all custom machined to my exact lengths and to allow pulleys, all of my hiwin 20mm linear rail (2x1.2m, 2x1m and 2x35cm) and 12 hiwin carriages, and a 2.2kW spindle plus VFD with collets and water pump and spindle mount.

Sounds like a lot of money, but those three things were the most expensive components and about 1/3rd of the total build cost.

I won't go into further detail about the import duty, but trust me don't be concerned. You'll get a text or email when the parcel arrives in the UK and you just pay online.

Thanks Andy - thats good to know. I'm spending a bit of time trying to learn fusion 360 and draw the thing now before I buy anything else !
I added an extra extrusion 120x40 to my order, so now have a 90x90 and 120x40 piece @1200mm to factor into the (sort of) L shape gantry design.

Ryan

CNCRY

14-02-2020, 12:02 AM

OK so I've figured out enough of Fusion 360 to model something - not going to win any awards but at least it's clearer and I can edit the design as needed.

27376
27377
27378
27379
27380

The blocks on top of the X carriages are set to 40mm thick currently
All rails are 1000mm , to be adjusted if needed
Aluminium profile on gantry is 120 x 40 with 90x90 on top.
The purpose of the ballscrew and ballnut running inside gantry plate is to allow an L angle (or perhaps long brush) to be fixed to the extrusion above the screw and cover the ballscrew from dust/chips
*

Issues I'm thinking of so far is the the Z axis clearance isn't huge, 125mm from top of baseboard to bottom of gantry, although probably OK for my needs.
The Z design with rail on front and top is based on the fact Z clearance would be even lower if I put rails on top/bottom of profile. I plan to add extra C shaped plates to side of Z axis to strengthen - will it be enough/OK design?
Y axis travel is limited by how far forward Z is - losing about 275mm so probably need to bring the carriages closer together and gantry plates narrower, maybe mount motor to back of gantry extrusion instead with pulley.
Any comments on those bits? thanks

Aluminium profile arriving tomorrow - only thing I've ordered so far, but will be good to get a feel for size. Also built a 1.2m square workbench for it , 25mm ply top and 50x100 wooden frame on castors, hopefully that'll be rigid enough.

Ryan

CNCRY

19-02-2020, 10:57 PM

Hi All,

I've spent some more time on the design - moved the dual X motors to the back, and added a pulley based drive to the Y axis (borrowed from Andy's build log!)
Also shortened the plate fixing gantry to Y rails to give more Y cutting area. I expect I'll get 750mm out of the 1000mm total Y length.

27423
27424
27425

For my Z axis, I'm planning to make this 350mm tall with 350mm rails and 265mm ballscrew.

I think I'm ready for a quote on linear components - would appreciate if someone could take a quick look and advise if there are any glaring issues?

These are sets from BST automation e.g https://www.aliexpress.com/item/32887382899.html?spm=2114.12010612.8148356.1.35f43 557qd67J5
Ballscrew sets to include ballnut and mount, BK/BF supports and coupler.

2 set 1610 ballscrews X @ 965mm long
1 set 1610 ballscrew Y @ 1000mm (With Pulley Machining)
1 set 1605 Z @ 265mm (With Pulley Machining)
X rail set 2 x 1000mm rail and 4 x Hiwin 20mm Flanged Carriages
Y rail set 2 x 1000mm rail and 4 x Hiwin 20mm Carriages
Z rail set 1 x 350mm rails and 4 Hiwin 20mm Carriages

Thanks.
Ryan

JAZZCNC

19-02-2020, 11:12 PM

AndyUK

19-02-2020, 11:32 PM

added a pulley based drive to the Y axis (borrowed from Andy's build log!)

I stole it from Joe, who I'm sure stole it from someone else. I'm reliably told it's called development!

Great progress Ryan, it's coming along.

Jazz's comments are spot on, and also your BK nearest the motor is back to front. Mention to Fred that your dimensions are for the screw part not total length else you'll end up short!

I'd recommend an F length of 30mm on Y and Z to give more room for those pulleys. Don't know if Jazz was saying 25 for the X couplings or the pulleys? Either way just gives more room to align that pulley.

I've noticed your gantry vertical plates are wider than the distance between carriages - the angle continues further than the carriage. Might be worth trimming that because it's essentially cosmetic in its current form and will be costing you when you order the plate.

CNCRY

19-02-2020, 11:37 PM

On the model, you show BOTH ends of the ball screws using BK bearings which are the fixed end bearings, which is the best way to fasten, BUT it's not the standard way. Usually, you have a fixed end BK bearing and a floating end BF bearing, so if you want BK on both ends you will need to tell Fred at BST otherwise they will machine them to standard.

Also mention you want the "F" Dimension which is the coupler portion at 25mm otherwise they will machine it 15mm.

Tell Fred you want the best BK/BF bearings not the cheap ones.

Thanks Jazz - the BK bearings in the image were more just to guide placement and I'd just been copying the same object in fusion 360 rather then using the BF, but I do intend to do it the standard way.
OK - will request a bearing upgrade too. As mentioned in another thread, no idea if BST are shipping out at the moment, so will check on that. Just being impatient to start building something:)
Does the design overall look OK? It's heavily copied of course with a few tweaks!
I do intend to take up your kind phone offer soon - I think electronics will be a Major learning curve so have many questions!
Ryan

Doddy

20-02-2020, 08:17 AM

Desertboy

20-02-2020, 08:40 AM

Hah! Yes, "Unless you're going down the linuxCNC route in which case I have no idea" :P

Reading it back it sounds like I'm saying don't use ethernet with LinuxCNC - it was meant as an "if you're using LinuxCNC there may be more appropriate options like onboard PCI cards".

I have a mesa PCI card I don't use at the moment but there is a rare problem with MESA PCI cards when installed in some machines will not boot.

I traced this to a PSU issue, I swapped 3 motherboards into that case before I realised it was the PSU that wasn't letting it boot. The Mesa people told me it happens in 1 in 100 machines.

As soon as I swapped the PSU it booted fine but I had to move the machine so I bought a standalone controller and put it on a catering table with wheels.

CNCRY

20-02-2020, 11:21 PM

Just a (genuine) question - have you considered belt-drive on the X as well as Y?, for me workshop space is a critical issue and being able to rotate the motors 180 degrees into the frame of the router would be a design goal if only to reduce the depth of the machine as it sits on the bench. If that's not an issue for you then ignore.

Hi Doddy, I considered this earlier but as the gantry is going to extend back on the X axis, beyond the cutting bed size anyway, then the motors don't add to the footprint, and slightly simpler to connect direct. It's on a workbench which is 120cm square, so gives me about 20cm for the motors/wiring etc!

CNCRY

20-02-2020, 11:30 PM

I stole it from Joe, who I'm sure stole it from someone else. I'm reliably told it's called development!

Great progress Ryan, it's coming along.

Jazz's comments are spot on, and also your BK nearest the motor is back to front. Mention to Fred that your dimensions are for the screw part not total length else you'll end up short!

I'd recommend an F length of 30mm on Y and Z to give more room for those pulleys. Don't know if Jazz was saying 25 for the X couplings or the pulleys? Either way just gives more room to align that pulley.

I've noticed your gantry vertical plates are wider than the distance between carriages - the angle continues further than the carriage. Might be worth trimming that because it's essentially cosmetic in its current form and will be costing you when you order the plate.

Thanks Andy - feels like the design is almost there now, drawing in CAD certainly makes things easier to tweak/measure and figure out what should work.
Yes good shout on the gantry - I've reduced the width slightly (50mm approx) so it can be cut from a smaller piece of aluminium.
Just waiting to hear from Fred @ BST , so thinking about how I'll actually machine the pieces now.
Have you found printing 1:1 and sticking to the piece worked well? Also what contact adhesive did you use there?
I've bought some centre drills / counterbores to test out . Also thinking to get a metal cutting blade for the large wood bandsaw to cut the angle. That or a blade in mitre saw but feels a bandsaw would cope more..

AndyUK

21-02-2020, 12:09 AM

Have you found printing 1:1 and sticking to the piece worked well? Also what contact adhesive did you use there?

Yeah it was a low-tech solution that worked quite well. Can get messy though, recommend some cellulose thinners and a rag on standby to wipe the other edges of the piece you're spraying, and obviously do it on a waste surface like cardboard. I got the wife to cut the printed bits out - shes a little bit more artsy and careful with a pair of scissors. It was then mainly a case of alignment as you put it on, trying to get a straight edge aligned with the edge of the metal. We found spraying half then putting on roughly worked well as you had a couple of seconds to adjust the paper slightly. Then fold over and spray the other half, and then flatten out.

Used Evostick Impact spray, but I'm sure any contact adhesive would do the job. This one is a bit costly, I probably nicked it from the in-laws....

https://www.amazon.co.uk/Impact-Multi-Purpose-Instant-Contact-Adhesive/dp/B0095RFILA

Helped a lot with the marking out. I used one of those push down centre punches, but others have used optical ones which look really good.

When you're finished drilling on them, get some lighter fluid to help remove the paper and contact adhesive. That was a nasty job... Then shine with scotch-brite.

I've bought some centre drills / counterbores to test out . Also thinking to get a metal cutting blade for the large wood bandsaw to cut the angle. That or a blade in mitre saw but feels a bandsaw would cope more..

I love the counterbores I got. Great little tools. Centre drills didn't really work for me, I just ended up starting everything with a 2.5mm.

I used a crappy old table top wood band saw, and it worked okay. Just get a decent blade. I remember learning that you want approximately three teeth in contact, and I was cutting 10mm and 20mm Ali, so I went with approx 5mm pitch blade. Slow but steady, lots of cutting fluid.

However, I only used that for un-important edges. I got Aluminium warehouse to do the main cutting to size and just cut pieces in two where they had to be ordered as one piece due to minimum piece sizes. Where I had to cut a piece that mattered, I'd use Aluminium warehouse's edge as the mating side. That way all the mating surfaces have square(er) edges - the bandsaw cut edges needed a fair bit of sanding afterwards!

CNCRY

28-02-2020, 12:11 AM

So the build has officially started - I should probably convert this to a Build log if that's possible!

27460

So the profile was joined using the self tapping M12 core screws, where the head slots into the 10mm profile slots and a hole is drilled though the profile to allow the T50 key to be inserted and tightened. This worked OK but I managed to almost break my wrist using a cordless drill and even a (cheap) impact driver struggled! Got there in the end and re-enforced with brackets.
I don't have any precision measuring tools at this point, but using the digital angle measure is 90.0 degrees on all angles and to 1mm across all dimensions.

Issue #1 - In my haste to add an extra piece of profile to my order (to have an L shaped gantry profile) the 2 profiles have different slot spacing. As far as I can tell the main issue is joining them. If these are joined simply by using the side gantry plates and socket head bolts to hold the pieces in contact is that a terrible idea? Could it be enhanced with some strong adhesive between the pieces to compensate. Really wan't to avoid wasting money on the extrusion if I can help it.. Any ideas?
27461

I've also placed the order with BST Automation - Thanks for the recommendations. All smooth so far, Fred seems very responsive and helpful. There are expected delays due to the coronavirus but it sounds like production is just slightly slower then usual.
Only linear motion components so far - 1610 ballscrews and 1605 for Z. 20mm Linear rails and Carriages. Flanged Type for X axis for stability as I'm using a wide plate.
For the blocks which will mount to carriages - Is Ecocast type aluminium recommended here? Quite pricey for 50mm thick block so want to be sure it's worth using this.
Also thinking of what you mentioned Jazz - adjustability. Would slightly oversize holes be the usual way to achieve this?

On electronics - I'm considering Hybrid steppers now, certainly on X due to the dual X motors and potential stalling. Any recommendations on models here?

Thanks!

Sterob

28-02-2020, 12:59 AM

27460
Issue #1 - In my haste to add an extra piece of profile to my order (to have an L shaped gantry profile) the 2 profiles have different slot spacing.

Is the bottom section a different Series? They both should be the same...ie Series 45( 45 mm between slots )?

CNCRY

28-02-2020, 01:07 AM

Is the bottom section a different Series? They both should be the same...ie Series 45( 45 mm between slots )?

Hi Stereob - yes correct, it's a different series. I hadn't realized until too late:( Hence seeing what I can do as a workaround..

JAZZCNC

28-02-2020, 08:30 PM

If these are joined simply by using the side gantry plates and socket head bolts to hold the pieces in contact is that a terrible idea? Could it be enhanced with some strong adhesive between the pieces to compensate. Really wan't to avoid wasting money on the extrusion if I can help it.. Any ideas?

It's not the best of ways but if you bolt the profiles together along there length as well as the ends it should be ok. Obviously, because the slots don't line up you won't be able to use the slots to lock together but you should be able to drill and tap them together from underneath with a few bolts.
Don't use adhesive.!!

For the blocks which will mount to carriages - Is Ecocast type aluminium recommended here? Quite pricey for 50mm thick block so want to be sure it's worth using this.

Cast plate isn't required but the plates must perfectly flat with parallel faces and exactly same thickness on both sides of machine. Rolled plate isn't flat or with parallel faces so unless you machine it flat and parallel then ground plate is your only choice if you want it right. Why 50mm thick.?

Also thinking of what you mentioned Jazz - adjustability. Would slightly oversize holes be the usual way to achieve this?

Try to keep the holes to correct size if possible. Only make oversize if needed.
When I say adjustability I mean don't machine plates with slots etc that lock things together unless the whole machine is built this way and on an accurate machine. Adding plates or brackets that allow adjustability is always a good idea. When making plates etc then adding slots rather than holes can help in some places but depends on machine design.

One of my methods is to use slots to allow adjustabilty then when it's all setup I'll lock it in place using tappered holes and pins.

On electronics - I'm considering Hybrid steppers now, certainly on X due to the dual X motors and potential stalling. Any recommendations on models here?

Wouldn't use anything else. These work well and allow AC or DC with voltages upto 70Vac or 100Vdc. This means you'll get good speed and with 5.5Nm you've plenty of power.
If you go for the lower powered motors just check the drives Max voltage because a lot of them are 50Vdc Max which will limit your speed.

https://www.aliexpress.com/item/32799547111.html?spm=2114.12010612.8148356.11.44bf 3421SaYv5O

CNCRY

01-03-2020, 12:57 AM

It's not the best of ways but if you bolt the profiles together along there length as well as the ends it should be ok. Obviously, because the slots don't line up you won't be able to use the slots to lock together but you should be able to drill and tap them together from underneath with a few bolts.
Don't use adhesive.!!

Cast plate isn't required but the plates must perfectly flat with parallel faces and exactly same thickness on both sides of machine. Rolled plate isn't flat or with parallel faces so unless you machine it flat and parallel then ground plate is your only choice if you want it right. Why 50mm thick.?

Try to keep the holes to correct size if possible. Only make oversize if needed.
When I say adjustability I mean don't machine plates with slots etc that lock things together unless the whole machine is built this way and on an accurate machine. Adding plates or brackets that allow adjustability is always a good idea. When making plates etc then adding slots rather than holes can help in some places but depends on machine design.

One of my methods is to use slots to allow adjustabilty then when it's all setup I'll lock it in place using tappered holes and pins.

Wouldn't use anything else. These work well and allow AC or DC with voltages upto 70Vac or 100Vdc. This means you'll get good speed and with 5.5Nm you've plenty of power.
If you go for the lower powered motors just check the drives Max voltage because a lot of them are 50Vdc Max which will limit your speed.

https://www.aliexpress.com/item/32799547111.html?spm=2114.12010612.8148356.11.44bf 3421SaYv5O

I did some more thinking on 2 profiles with different spacing - as the 2 do not need to align on the face in the design, I can offset the top piece by 5mm so at least the front slot is in line, then bolt/tap the rear.

OK great - I'l either go for Ecocast or see if I can get it milled. Its 50mm thick as the block is intended to add some Z clearance for the gantry. Without it clearance is only about 100mm, so takes it upto 150mm .

27466

Hybrid Steppers are slightly more reasonable price then I had expected Vs standard steppers. Looks like the LC60H2102 (4.5Nm) and LC60H2112 (4.8Nm) both also support 100VDC with the same LCDA86 Driver, although strangely are twice the price as the 5.5Nm from what I can see!
Would the 5.5Nm be overkill on the Z axis ?
I noticed the 5.5Nm has a 35mm shaft and keyway, which should help with pulley mounting. How does that work with direct coupling though, a keyway and standard shaft coupler?

Thanks

CNCRY

06-03-2020, 12:25 AM

700 x 500 x 250mm steel cabinet arrived today from TLC. Very solid and heavy @ 20kg. - hopefully everything will fit in based on previous builds on here! I see Andy had 800x600 which had a little space spare.
While I wait on the linear motion parts from BST - electronics are being planned, really steep learning curve here for me and hoping I can figure it all out with some of your help.
With the LCDA86 driver Jazz recommended, what voltage would be ideal. Its up to 100Vdc and I see a few people have used 68V - so would give some margin but would that be at expense of too much power?
LC60H2112 is listed as 5.6A current, so with 4 motors do I need 22.4A x 68V = 1523VA PSU? Sounds huge.

I'm trying to take each component in turn and map out the connections - first the driver to AXXB-E. Except for ALM I can't figure out which other terminals need to be connected if at all ? For example ENA+, Pend, and the Encoder E* ones.
AXXB manual refers to just Step and Dir.

27524

Edit..Just realised VCC/GND wrong colours on that IMG..

Thanks
Ryan

AndyUK

06-03-2020, 12:44 AM

700 x 500 x 250mm steel cabinet arrived today from TLC. Very solid and heavy @ 20kg. - hopefully everything will fit in based on previous builds on here! I see Andy had 800x600 which had a little space spare.

Yeah you'll be fine :) 800x600x300 was overkill. I have no idea how Joe filled 800x800x300.

I'm trying to take each component in turn and map out the connections - first the driver to AXXB-E. Except for ALM I can't figure out which other terminals need to be connected if at all ? For example ENA+, Pend, and the Encoder E* ones.
AXXB manual refers to just Step and Dir.

Good plan. Generally speakings, Step and Dir are the two required ones.

Enable turns the drive output on or off to prevent the motor turning without killing power to the drive, usually when left disconnected the motor is just enabled by default.

Alarm should output a fault signal to the AXXB if something goes wrong. Best to have it connected somehow if you can, but there are a lot of options about exactly how you wire it up. E.g. it could estop the system on fault, or just tell the AXXB to pause.

Pend appears to be 'positioning completion signal', encoder and the motor phases should be the wires from your motor.

JAZZCNC

06-03-2020, 09:57 AM

With the LCDA86 driver Jazz recommended, what voltage would be ideal. Its up to 100Vdc and I see a few people have used 68V - so would give some margin but would that be at expense of too much power?
LC60H2112 is listed as 5.6A current, so with 4 motors do I need 22.4A x 68V = 1523VA PSU? Sounds huge.

You don't need 22.4a you only need approx. 60% of total current draw because of how the drives work using PWM etc which I won't get into. Also you'll rarely max out all motors so got little more leigh way in use.
I would use AC and do away with the need to rectify and Caps etc required for DC. This is what I would use with those drives wired AC. Wire the secondaries in parallel and you'll end up with approx. 11a which isn't quite 60% but still more than enough.

https://airlinktransformers.com/product/chassis-mounting-toroidal-transformer-standard-range-cm0750265

I'm trying to take each component in turn and map out the connections - first the driver to AXXB-E. Except for ALM I can't figure out which other terminals need to be connected if at all ? For example ENA+, Pend, and the Encoder E* ones.
AXXB manual refers to just Step and Dir.

Start simple, if your not used to wiring things like this don't try and wire it all in one go it will just blow your mind. Start with basics first and do it in stages.

I would start by setting up the main latching E-stop circuit and getting movement just with Step & Dir. Forget, enables and alarms at first they can be added later.
Next wire in Home/limit switches. This then gives you the basics or a working machine.
Now you can start adding other features like Alarms, enables etc and controlling any external devices using outputs etc like spindle control.

My favourite saying is "Treat it like eating an elephant, one bite at a time."

Edit: With the cabinet don't stress out over this either, concentrate on layout and wire routing , the main thing is to keep low voltage signal wires away from higher voltage wires as much as possible and make sure you use Star grounding. If your using a VFD and thinking to put in cabinet just pay close attention to where the main spindle cable goes, I'd also suggest you don't put it near the main controller.

CNCRY

10-03-2020, 12:13 AM

OK so I've listened to the start simple advise and taking each part at a time! So plan is to sort out the cabinet layout, power distribution, e-stop and switches first, then add controller and drives once the machine is actually built.
That way the low(er) cost and less complex items can be fitted now and drivers / controller / home and limits / alarms / faults to be added once the machine is built, and finally VFD and spindle.

I have this for the cabinet layout - does it look OK or any issues?

27535

I'm planning to buy these - could someone confirm they are OK choices, especially the contactor! Looks like it is DC

https://www.rapidonline.com/mean-well-sdr-75-24-24v-76-8w-slim-high-efficiency-psu-85-5684
https://www.rapidonline.com/schneider-lc1d12bl-3no-12a-24v-5-5kw-contactor-66-1939

Couple other questions from the never ending list:)
- Do I need to Fuse the drivers? They have overcurrent/voltage but I notice some people have?
- Are EMI filters needed with decent star grounding? I'm planning to add the EMI filter option on the transformer.

Possibly one day I can answer some questions:) On a side note, looks like quite a few builds stall or just about complete and then people disappear from the forum, big thanks to those who stick around to keep helping others.

Ryan

Neale

10-03-2020, 09:14 AM

Personal view - there is little point in providing fuses for the drivers. A fuse will never "protect" a driver as the semiconductors in the driver will let out the magic smoke well before the fuse can react in the event of a major fault (and I'm thinking short-circuited motor wires, for example). If the built-in protection doesn't work, then it's already too late for a fuse. Where a fuse might help is in the output of the driver power supply, or maybe in the input to it. In the event of a fault in a driver that causes a high current draw, this will protect the power supply. In fact, the only electrical fault that has happened in my own control box was an internal short in the toroidal transformer which took out the fuse on the input (mains) side - fortunately. Generally speaking, fuses do not "protect" equipment - they help stop wiring, etc, bursting into flames when something has already failed. As I say, this is a personal view and others are paranoid about fuses everywhere. Be interesting to hear if these fuses have ever "saved" anything!

JAZZCNC

10-03-2020, 06:10 PM

Personal view - Be interesting to hear if these fuses have ever "saved" anything!

My personal view is that it's stupid not to fit a fuse just to save a few pence. Why risk an £80 drive for the sake of an 80P fuse to protect from the unknown.!.

To answer the question have they ever "saved anything" then it's a BIG FAT YES I've had many cases where things like loose wires have shorted or been rubbed through etc. The point being your not actually always trying to protect the device but the system as a whole from unforeseen circumstances so spending a few quid more for fuses to protect valuable parts of the control box is a No brainer to me.

AndyUK

10-03-2020, 06:38 PM

Be interesting to hear if these fuses have ever "saved" anything!

I've already buried the spindle in the work a couple of times, both times have 'gently' blown the VFD fuse before any damage was caused elsewhere. The power loss to the VFD also causes a fault on the controller so stops the motors, which is kinda nice.

I have this for the cabinet layout - does it look OK or any issues?

Three things spring to mind:

VFD Spacing against internal walls. Read the manual for how far it should be away to allow adequate air flow.
I'd keep earth near Line and Neutral, thats where it comes in after all, and a lot of the big ticket earthing items will be mains voltage.
You've made a good start trying to separate voltage levels, but the 5V PSU should be at the low voltage end of the cabinet rather than its current position near 65V DC.
Think about air flow through the cabinet - At the moment your drivers will get decent flow, but the VFD won't. What direction are those fans? I orientated my drivers to allow maximal air flow through their heatsinks, at the moment your heat sinks are at 90 degrees to the air flow.

Will it work in its current state? Sure. None of these things are big issues, just minor points.

I'm planning to buy these - could someone confirm they are OK choices, especially the contactor! Looks like it is DC

https://www.rapidonline.com/mean-well-sdr-75-24-24v-76-8w-slim-high-efficiency-psu-85-5684
https://www.rapidonline.com/schneider-lc1d12bl-3no-12a-24v-5-5kw-contactor-66-1939

You've gone for the high efficiency and expensive one, is there any reason? This is the alternative to save £10.
https://www.rapidonline.com/mean-well-ndr-75-24-24v-76-8w-slim-economical-din-rail-psu-85-5678

Contactor seems okay.

Couple other questions from the never ending list:)
- Do I need to Fuse the drivers? They have overcurrent/voltage but I notice some people have?
- Are EMI filters needed with decent star grounding? I'm planning to add the EMI filter option on the transformer.

Extra fuses won't hurt.
The advice I found at the time was that some people needed to plug the VFD in at the other end of the workshop to reduce the noise back from it, and I wanted to be able to power everything from the same socket. The EMI filters I used were about £5 each, and although I have no idea if they're needed or not, they do allow me to operate without noise issues with everything running off the same 13A socket.

Doddy

10-03-2020, 06:40 PM

Aha, the old benefit-risk balance.

The fuse is cheap, however, the probability of it protecting a driver with a shorted output is uncertain - I can imagine a driver without overcurrent protection popping before the fuse depending on how much you've pissed off your local deity.

The real purpose of the fuse is as a safety device to cover the fault condition and something in the high-hundreds VA rated transformers making something go bang. Or Pfftt! Or Whoosh!. Or whatever sound a decent arc makes... something like Pzzzzat! It could save the transformer as well which could be a good part of a hundred quid worth. And if it avoids a fire, then it might save on the insurance excess.

A fuse on the drivers can't be considered a bad thing but don't rely on it protecting the drivers.

JAZZCNC

10-03-2020, 06:59 PM

I have this for the cabinet layout - does it look OK or any issues?

27535

You need to think about how the wires run and trunking. how you have it there would be awkward for running wires etc.
I would move the drives away from the Transformer and bring the DC PSU and MCB's etc down near the Transformer so all together in one area. If you have room even bring the VFD into the same area, this way all the high voltage stuff is together.

I would have the drives and controller close together to keep Signal wire runs short as possible. Separate the high power stuff from the Low voltage stuff by placing high and low in the case with Terminal blocks and Relays etc along with trunking between them, essentially dividing the case into 3 areas.
This doesn't matter if it's separated horizontally or vertically, for instance, I often run the drives along the sides of the case vertically as it's easier to wire them. On the opposite side, I will place VFD at the top and PSU, etc below. In the middle will be Terminals and Controller.

Also, I would think about having 2 fans in the case to create a positive pressure in the case to push hot air out.

Edit: Noticed that you have a Pilz relay shown, you don't actually need a safety relay. A normal Relay will work just as well and save you a lot of money.

Lastly, looking at your drawing the scale looks wrong on the parts shown so be very careful when planning out the box because it's SO EASY to run out of room. Often the case will look massive when empty but it quickly fills up. Also if you haven't got the box to measure from then allow a little extra because things like hinges or Earth clamps etc can rob precious space and easily screw up layout plans.
Also if not got a case and solely planning layout in Cad or on paper then I'd try to get exact dimensions of any components because again can soon run out of space and no matter what you do or how you twist things around it just won't fit.!

CNCRY

11-03-2020, 01:23 AM

27555

Attempt number 2 - tried to separate Low/High voltage more and incorporate some other suggestions. Airflow intake at the bottom and out at the top, by VFD fan.
I checked the scale and believe its correct - cabinet is 700mm x 500mm . Although the DIN rail items are NOT to scale yet, the DIN rail is. I'll take some photos when parts physically arrive..
I think the conclusion is that fuses are v unlikely to be a negative addition, and probably positive, I'll add these between transformer output and Drivers AC input - probably 5/6A.
I did buy a PNOZ already as I made an ebay offer on one new much below "retail" price and got unexpectedly got accepted.

Andy - yes good shout on 24V PSU, just chose wrong one.
Think I'll need to add a fire extinguisher to the list too before I get started:)

AndyUK

11-03-2020, 10:33 AM

Looks like good progress.

As Jazz mentioned you now need to consider trunking and cable runs, at the moment any vertical runs are awkward.

I'd also consider putting the contactor in the high voltage section.

JAZZCNC

11-03-2020, 08:23 PM

Here's a couple of pics of boxes which might help give some ideas, These range from tiny 300x300(red) to 800x600 boxes.

There's no one way which is better than any other so don't stress over it, just be mindful of high and low voltage wire separation along with grounding and you won't have any issues.

27564 27561 27560
27562 27563
27565 27566

CNCRY

17-03-2020, 12:27 AM

Thanks, Some useful ideas there Jazz, with everyone staying close to home at the moment, I had some time to get the E-stop working along with fixing DIN rails and mapping out where things will go:)
After attempting to drill the first 16mm hole in the cabinet with a normal bit I realised what step drills are for and did the rest.. great tool.

27632
27633

Hoping to have linear motion parts finally this week from BST. Physically building again is starting to feel more daunting then the electronics now.!
Thinking about limits and home too -

From what I understand a limit and home can be the same physical switch.
So I'd expect you need a limit on each end of X axis, with one end doubling as a home. Then the same on Y, and Z can have a single switch passed on upper and lower limit, and say upper can be home.
So not sure why people mention 2 X's being used - surely both limits are at the same point as the 2 X axis are parallel?

Edit - Fuse question. The Transformer will be 750VA - 2 x 65V output. I ordered 10A D curve MCB seen on others diagrams, but I'm thinking 750VA/230V is approx 3A so 10A is very high. Or am I missing something (most likely)

Ryan

JAZZCNC

17-03-2020, 07:30 PM

From what I understand a limit and home can be the same physical switch.
So I'd expect you need a limit on each end of X axis, with one end doubling as a home. Then the same on Y, and Z can have a single switch passed on upper and lower limit, and say upper can be home.
So not sure why people mention 2 X's being used - surely both limits are at the same point as the 2 X axis are parallel?

Ok well regards the X-axis having 2 switches this only applies if you are using twin screws, one side will have a switch that works for limits and home, the other side as a switch just for home. Reason being you home each side independently to square up the gantry. But you only need a limit on one side.

Now regards having a switch at each end then there's another way, which IMO is the best way and uses just one switch on each axis.
You place the switch on the moving part ie: Gantry and Y axis which then looks for a target at each end of travel. The Z-axis just uses a fixed switch at the top of travel which looks for the target on the moving part.
This means you have less switches and less wiring to go wrong.This can be done with either proximity or Microswitch type's.

AndyUK

17-03-2020, 09:18 PM

Edit - Fuse question. The Transformer will be 750VA - 2 x 65V output. I ordered 10A D curve MCB seen on others diagrams, but I'm thinking 750VA/230V is approx 3A so 10A is very high. Or am I missing something (most likely)

I believe that D curve MCB is sized to cope with the inrush current. A 1KVA transformer will only need approx 4A in steady state on UK mains (varies with min input voltage and efficiency) but the inrush can be something like 100A for a very short amount of time (dimming lights anyone?).

CNCRY

26-03-2020, 12:14 AM

Ok well regards the X-axis having 2 switches this only applies if you are using twin screws, one side will have a switch that works for limits and home, the other side as a switch just for home. Reason being you home each side independently to square up the gantry. But you only need a limit on one side.

Now regards having a switch at each end then there's another way, which IMO is the best way and uses just one switch on each axis.
You place the switch on the moving part ie: Gantry and Y axis which then looks for a target at each end of travel. The Z-axis just uses a fixed switch at the top of travel which looks for the target on the moving part.
This means you have less switches and less wiring to go wrong.This can be done with either proximity or Microswitch type's.

Hi Jazz - So as I have twin X screws, if I go for the moving option on gantry I just need the single physical switch on each X (one acts as limit/home the other just home) and I have contacts at each end the switch triggers?
Then Y needs only one switch using same setup?

Thanks

CNCRY

26-03-2020, 12:32 AM

My linear motion parts are finally here! Happy with the service from Fred at BST - all parts received and in good order. Took a fair few extra weeks but with the worldwide situation at the moment not at all surprising!

27672

Looks like most aluminium supplies however are shut so maybe time for more electronics..

So today's question - does anyone know of a coupler for a 10mm end of the ballscrew to a 10mm with 3x16 keyway (on the motor shaft)
I got a load of "oldham" couplers from BST but they are 7mm/10mm bore with no keyway. Stupid question but does the keyway detach?
The problem is the hybrid steppers are not standard 7mm shafts!

Thanks
Ryan

JAZZCNC

26-03-2020, 12:55 PM

Hi Jazz - So as I have twin X screws, if I go for the moving option on gantry I just need the single physical switch on each X (one acts as limit/home the other just home) and I have contacts at each end the switch triggers?
Then Y needs only one switch using same setup?

Thanks

Yep works exactly as you describe.

CNCRY

02-04-2020, 12:38 AM

So I was about to mount my 750VA Toroidal transformer to the cabinet back board with the supplied fixing bolt, metal plate and large rubber washers
e.g this kit > https://airlinktransformers.com/images/products/photo1_CM5.JPG
Plan was to drill and tap the metal back plate and secure the bolt into it.
Then I read this - https://diy.stackexchange.com/questions/149993/how-to-mount-toroidal-transformer-in-metal-chassis
From what I understand the bolt itself plus the top mount plate and chassis can form a C shape around the winding and induct a current. People mention fires and things blowing up which I'd like to avoid!
So now I'm thinking to mount to a phenolic (insulating) sheet so the mounting bolt does not touch the cabinet back plate directly. The transformer also has an earth wire.
Any issues with this, or better suggestion people use?

Thanks

Clive S

02-04-2020, 08:43 AM

Doddy

02-04-2020, 08:47 AM

The power of the internet! One of the key attributes of toroidal transformers is a very low flux "leakage" which will limit any potential induced current. I understand the argument but would challenge the actual risk - if I had a toroidal going spare I'd set up an experiment (it's interesting, and this is the first that I've heard of it, and the evidence from the internet looks to be more anecdotal than academic). Actually, because of this thread I've ordered a toroidal just for this experiment - I'll report back in a few days. My thoughts are any current is likely to be measurable but insignificant. The risk can be mitigated in any event by isolating (air gap) the top of the bolt from the chassis to avoid the short.

Edit: What Clive said. The more I read the more interesting this experiment might be.

Doddy

02-04-2020, 10:05 AM

Wow!, just... Wow! I take back everything.

Following the previous post I'd realised I have a bench PSU with a chunky toroidal transformer that I'd previously hacked to pieces. Sounds like a good experimental platform. Ignore all the crap on the bench - I really need to tidy up.

Pic 1: General topology, next-to-nowt resistance (0.1R) from the top of the mounting bolt to the chassis.
27703

Pic 2: Open circuit Vacrms reading from the top-bolt to chassis - about half a volt. A lot more than I'd expected and enough to ignore the fancy stuff with a shunt resistor and 'scope, and go straight for the "blow-the-hell-out-of-the-meter" probe...
27704

Pic 3: Current short, top bolt through meter and 3 metres of meter leads to ground. Some 3.1A.
27705

So, yeah, isolate that top bolt!

JAZZCNC

02-04-2020, 12:05 PM

So now I'm thinking to mount to a phenolic (insulating) sheet so the mounting bolt does not touch the cabinet back plate directly. The transformer also has an earth wire.
Any issues with this, or better suggestion people use?

I'm going to throw a spanner in the works here and point out that I've built dozens of machines that use the bolt thru chassis method with rubber pads and I've never had any issues with shorts, fires or getting zapped with stray volts/current etc.
Like Clives mentions it's a Big No No earthing to the bolt but other than that then you won't have any issues provided the transformer sits on the rubber pads.

So just get on with it and don't worry is what I'm saying. If you want to put a rubber washer on the bolt then why not for what it costs but I wouldn't mess around with Phenolic boards etc.

CNCRY

02-04-2020, 11:18 PM

Thanks for all the replies - I wasn't expecting a full on experiment Doddy :) Good to have some real results though as everything I found was purely theory, no-one tried it until now!
So in summary if the bolt is used along with the chassis to form a "loop/partial loop" around the core then there is some serious potential for amps to flow, but its low risk if the bottom of the bolt only contacts the chassis, as Jazz mentions this is commonly done with no apparent issues.
I happened to have a piece of phenolic offcut so ended up using that on some spacers, plus the bolt itself has a rubber washer between the head and the metal transformer plate. Probably overkill - and I'm sure I'll do something else instead !
PS before I power up.. Red and Yellow (Vsec from each secondary) and Orange/Black (0V) are connected together - is that all correct for parallel?

27708
27709

Ryan

Doddy

03-04-2020, 08:06 AM

It was an interesting and eye-opening (for me) quick test - I've learnt from it so all is good for me. Don't blame Jazz re. the mounting method - that's how industry does it - single bolt through the grounded chassis. As Clive says the two rubber sheets are a form of mechanical protection to allow you to positively clamp on the transformer windings without deformation of the windings and compromising the insulation coating on those windings. The sequence is chassis (bottom) -> neoprene washer -> toroidal transformer -> neoprene washer -> steel plate -> nut.

Re. colours - that's a less than useful label on the transformer but I'd interpret it the same as you say - positional reference indicating the phase of the windings. I've had a quick look on Airlink's website and there's no further useful information that I could spot. Your fuse will tell you if it's wrong.

I've missed the earlier conversation on this but guess you're using AC to power the stepper drivers (no sign of provisioning for rectifier and caps) - I'd think carefully at this time of routing the secondaries in a tidy(!) route away from any low-level signalling, to the drivers - I'm sure you're looking to route to the top of the picture of the box.

JAZZCNC

03-04-2020, 10:29 AM

Don't blame Jazz re. the mounting method - that's how industry does it - single bolt through the grounded chassis.

Ye go on blame me I've got wide shoulders I can take it..:joker:

Re. colours - that's a less than useful label on the transformer but I'd interpret it the same as you say - positional reference indicating the phase of the windings. I've had a quick look on Airlink's website and there's no further useful information that I could spot. Your fuse will tell you if it's wrong.

Here you go you blind bugger.

https://airlinktransformers.com/post/chassis-mounting-toroidal-transformers-technical-notes

Doddy

03-04-2020, 10:32 AM

Admittedly - I just looked at the technical data for the transformers, e.g. https://airlinktransformers.com/product/datasheet-pdf/chassis-mounting-toroidal-transformer-standard-range-cm0750255 ... which you really would think that they'd replicate that most basic of info. Even on the link you provided there's no clear statement as to the phasing of the windings (I've seen better data sheets).

Edit: Actually, I take that back. The link you provide does, in the schematic symbol, give the phase relationship of the tails.

CNCRY

14-04-2020, 12:42 AM

So the transformer lives, and nothing exploded/shorted etc! I did a quick reading across the output and its 70V, which is higher than the 65V its rated at. Is that normal with no load applied? The drivers are up to 70VAC and don't wan't to fry them..

Made some progress over the long weekend - if only I had a CNC machine this would be so much easier:)

Reading some of the new threads I've been re-thinking and slightly concerned that the accuracy I'm building too could result in inaccurate final results.
As this is all "by hand" and printing 1:1 scaling, drill holes are perhaps up to 1mm out, I'm using a digital caliper and angle measuring device during the build, but check as much as possible
There is some slight adjustment by the hole sizing on everything - how much can the software make up for sub mm "corrections"
Maybe overthinking it - but also don't want to end up with something not accurate after all the effort.
As I haven't owned a CNC machine before I don't know what accuracy I'd like, but for example if I could produce something like the Aztec calendar I'd be happy..

Some photos of current build.

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27803
27804

Thanks

Doddy

14-04-2020, 07:19 AM

Re. your 70VAC. The rated 65VAC would be at the rated power of the transformer, and off-load (or lighter loaded) you would expect the terminal voltage to rise. There's normally an attribute "regulation" applied to the transformer that describes the difference from full load to off load - typically 5-10%, which looks to be the sort of zone that you're looking at here. Reading AirLinks's technical data sheet I can't find the regulation value (though I clearly struggle with their site), although they identify the attribute, and strangely relate it to efficiency which is a new one on me (they're kind of right, but the actual attribute of regulation is in the context of change-of-voltage).

Others here will (rightly, in my eyes) present a cautious (but reliable) approach to all this and recommend a 10% headroom on supply voltage to rated voltage. For a drive with 70VAC max input this is likely to result in a recommendation of 60VAC. Even that's a bit simplistic but it's a useful rule-of-thumb. So lets have a think about where you are now (no-man's land).

Firstly, what you know is what your meter is telling you. That's probably +/-1% or so, and realistically on a cheap meter (just making a blind assumption here) which isn't calibrated and on an AC supply that's probably going to give you +/-2V uncertainty on the display.

Next you're going to have an issue with line regulation. The UK grid used to be 240VAC (domestic), it's currently around 230VAC (-6%/+10%) trying to get to a EU standard of 220VAC (-10%/+6%). Your transformer is likely rated with primaries at 220VAC. If the mains is at 230VAC then you have a 5% uplift on the primary voltage - which will translate to a 5% uplift on the secondary voltage. That's also about where you find your measured secondary. Worryingly the mains supply can rise a fair bit above this - if you're sited close to a big transformer (e.g. on an industrial estate) you might find the supply around the 250VAC mark, with an appropriate rise in terminal voltage on the secondaries.

So, in a nutshell, you're likely to be at or slightly above the rated voltage of the drivers. And you have to figure on this before you consider any load from the drivers on the transformer. And, in an e-stop situation the load from the drivers is likely negligible, so you should design with this open-circuit terminal voltage in mind. I am a bit surprised that your build has got to this stage without attracting some concern from this thread.

Now, I don't know where to start with the driver. Quickly looking back I thought you was looking at LCDA86's - but one of your diagrams shows a LCDA86H - I think that 'H' is significant here as it raises the operating voltage and introduces a AC-supply option to what was previously a DC supply-only, and at a higher voltage. Clearly the non-H variant would require you to rectify the supply and you'd be so far beyond the rating I'd expect you to blow the drivers. If you do have the 'H' variants, then I think you're on the ragged edge.

You might, on paper, be in spec, but only just. You might also be conscious of supply line regulation and want to consider a little head room between the transformer output voltage and the max input voltage of the driver. You might (I would) also squint at the max rating of the driver and wonder if the designer built in some spare float in the electrical design - but the accountants usually engineer that out. Clearly I'm uncomfortable at the voltages (and power!) that you're playing with. It will probably work, but you might expect that the driver to be running to the limit of what it can, and you might find that the life of the driver is compromised, or, that it lets the magic smoke out when you first apply power, or that it runs fine until the end of time. The problem is you're essentially on/outside of the specification of the device and all bets are off.

Personally I'd probably risk it if I could afford to replace the drivers if needed. But, that's a personal (and some would say foolish) choice.

Ideally I'd have chosen a transformer closer to 55VAC secondary and give myself plenty of headroom.

Other than swapping components (drivers or transformer) for others, is there anything you can cheaply do?... not easily - you are looking to drop the terminal voltage without dissipating huge power (heat).

You could add a couple of bridge rectifiers on the secondaries, in series - rely on the non-linear behaviour of the diodes to introduce a typical drop of a couple of volts per device, and throw them onto the cabinet to passively cool them. At full chat these would dissipate about 20W each - not insignificant, but they would provide better regulation than a chunky resistor. The first thing that the driver would do internally is rectify and smooth the supply - all you're doing is adding a pre-rectifier rectifier... it'd work but it's not elegant.

In theory, you could remove a number of windings from the transformer. I wouldn't touch this solution myself - if only for the buggeration involved with this.

Beyond that you're talking serious solutions that would add cost, weight and power. Nothing springs to mind that provides an elegant solution.

Are you beyond the point of returning and swapping the transformer? If not, I'd give that a shot. Next I'd look to sell/swap on the transformer as near-new here, you might be lucky. Or, you can risk it. You might be lucky.

EDIT:

Going back to where I came into this thread... you could always short out the mounting bolt on the toroidal... I hear that puts a bit of a load on the transformer :cower:

I'll get my coat.

There's another option with transformer design. You could wind maybe 10 - 20 turns of 13A-rated (min) insulated flex in the opposite direction onto the transformer per secondary, and feed this in series with each secondary. If in phase it'll add a few volts, or if you swap the phase it'll reduce by a few volts (you'll not be able to tell the phasing - just try either way to wire them and measure to work it out). I'm not advocating this, nor will I do the experiment to prove it. It'd introduce additional losses (power) into the transformer but if you was in a corner it might offer a solution.

AndyUK

14-04-2020, 08:48 AM

Reading some of the new threads I've been re-thinking and slightly concerned that the accuracy I'm building too could result in inaccurate final results.
As this is all "by hand" and printing 1:1 scaling, drill holes are perhaps up to 1mm out, I'm using a digital caliper and angle measuring device during the build, but check as much as possible
There is some slight adjustment by the hole sizing on everything - how much can the software make up for sub mm "corrections"
Maybe overthinking it - but also don't want to end up with something not accurate after all the effort.
As I haven't owned a CNC machine before I don't know what accuracy I'd like, but for example if I could produce something like the Aztec calendar I'd be happy..

First off, looks like some great progress in the photos, well done!

Regards the by hand - quite a few of us have used this method to good results. Yes, sometimes you cock it up, but just be slow and methodical double checking measurements.

No idea of your experience so lets ensure we hit all bases; make sure to centre punch well (optical if possible - the press type I also like), and let the drill bit align to that punch mark (if you clamp too tightly aligned slightly off, the bit won't happily sit in the punch crater). Use the drill press as much as possible (but check its square to the plate in both directions). If you're not using printouts, use marking dye. Set your digital calipers to the value from a reference surface, lock them off, then use them to scribe the line. When using a steel rule, never use the end for final marking (its a bit variable), always align to markings on both sides (e.g. to measure 10cm I'd align the 1cm mark and the 11cm.) - Now check using the end on the first mark!

If you come to fit components together and the holes are a bit out, you can always identify troublesome ones and widen only those. An M5 clearance hole already gives you 0.5mm of wiggle room, a 6mm hole isn't going to be the end of the world. Worst case is you have to make it again (oh no!) or remake it using the CNC later.

Regards accuracy - mostly to do with how you align the linear rails and screws. Use a dial gauge and get everything running smoothly and true to a reference surface. In your case this is mostly on ali extrusion or cast ali plate, so the height of the rail shouldn't be a massive issue - shim slightly if required, and you'll have plenty of left-right wiggle on the extrusion T slot. Your main problem will be aligning the two sides of the long axis so the rails sit at the same height. You won't go too far wrong if things move smoothly. Avoid software corrections as much as possible - the main one is the steps-per-unit, which shouldn't be too far from the calculated value (if it is very different, somethings probably lose).

JAZZCNC

14-04-2020, 09:35 AM

Now, I don't know where to start with the driver. Quickly looking back I thought you was looking at LCDA86's - but one of your diagrams shows a LCDA86H - I think that 'H' is significant here as it raises the operating voltage and introduces a AC-supply option to what was previously a DC supply-only, and at a higher voltage. Clearly the non-H variant would require you to rectify the supply and you'd be so far beyond the rating I'd expect you to blow the drivers. If you do have the 'H' variants, then I think you're on the ragged edge.

As far as I know there as never been an "S" version of this drive. I think you may be confusing these with the AM882S which did have an AC "H" version. These drives take both AC or DC.

Now your right on the edge with the voltage so your incoming supply must be on the high side. These drives will run at that voltage and won't give you any trouble provided your incoming supply doesn't fluctuate. The drives do have over-voltage protection, so they should protect them selfs from slight peaks and you will probably get a drop when under load. Only you know your incoming supply so only you can evaluate the risk.

The other option if you don't want to risk it is to throw a bridge rectifier and some Caps on it and go with DC.

If it helps you decide all I can say is I've run these drives at the ragged edge on volts before (I live next to the transformer and my supply can hit 256Vac so my supply is like a box of chocolates.!) without any troubles but I've also blown one of the smaller 50v versions by accidentally pushing too far so they only protect upto a point.!

Or buy a lower-rated supply that suits your incoming supply better. ( If it helps I'll take that one from you )

Doddy

14-04-2020, 09:40 AM

Yeah, was referring to the drive without alpha postfix - the stock LCDA86 - that has a much lower (and DC only) operating voltage. Take your point on the 'H' version.

JAZZCNC

14-04-2020, 09:56 AM

CNCRY

14-04-2020, 02:38 PM

Thanks everyone for the replies , no way I'd get throug h the build without the help here !
So I think the best option is going to be new transformer, with the cost of the drives at risk, and fact I'd prefer the simplest approach !
So to be 100% here, 60v or 55v to be safer if supply varies to high side . Will I lose much power @ 55V? And stick with 750VA?
Will PM you about other transformer if interested jazz.

Clive S

14-04-2020, 04:14 PM

Andrewg

14-04-2020, 04:17 PM

Doddy

14-04-2020, 04:19 PM

Will I lose much power @ 55V? And stick with 750VA?

As I understand it (and I might misunderstand the theory) you're not losing power, as such, but top-end speed/torque. But listen to Clive.

CNCRY

19-04-2020, 11:22 PM

Gantry Sides done - need to counterbore the M12 bolts slightly but waiting on a 13mm drillbit for clearance hole..
27880

Ended up ordering a new 60V output transformer. Fingers crossed I'll also have the closed-loop steppers and drives turning up in next few days. :)
Lichuan 5.5Nm - LCDA86H+LC60H2127 > https://www.aliexpress.com/item/32799547111.html?spm=2114.12010612.8148356.11.44bf 3421SaYv5O

I'm thinking about cable management, its probably been a bit of an afterthought so far, but I'm thinking having it in my hands will be easier to "visualise". From other post's I'm thinking something like https://www.ebay.co.uk/itm/R38-18mm-x-37mm-Black-Nylon-Flexible-CNC-Semi-Enclosed-Cable-Drag-Chain-1M-UK/163618534489 or will that be underkill?
I'd have 2 x 8mm coolant pipes (and 1 air TBC), 1.5mm CY for spindle, Z and Y motors, encoder cable? Y and Z limits.

Also trying to find the right pulleys for Y and Z - planning on 15mm HTD5 (10mm bore) in 1:1 ratio - but how many teeth do people go for?

CNCRY

19-04-2020, 11:28 PM

Watching thread with interest, as admire how you have got stuck in and learning as you go. I am trying to get a clear plan and design before spending a penny......so happy to learn from your journey.

No help on electricals, but back to printer paper plans. I use this all the time for woodworking templates. You want a spray can of 3M '77' good for temporary and permanent bonding light weight materials.

Keep going and keep sharing gotchas!

Thanks Andrew - I researched lots before starting but I find its easier to get started and "fix" some variables in the design otherwise I was going round in circles thinking and changing ideas. Probably means I will have a few gotcha's but hoping not too many! the help on this forum is great also, and helping me get a machine built which was just a pipe dream 6 months ago.

JAZZCNC

19-04-2020, 11:50 PM

Also trying to find the right pulleys for Y and Z - planning on 15mm HTD5 (10mm bore) in 1:1 ratio - but how many teeth do people go for?

20T are what I find best, don't go less than 18 because it makes it difficult with the boss size and you don't have much left for the grub screws. Also, don't try boring them by just drilling on a drill press, they need to be drilled and reamed accurately. I suggest if you haven't got a lathe or a very very good drill press or Minimill then buy them already bored.

CNCRY

22-04-2020, 12:46 AM

27930
The good news - I now have 4 closed loop steppers and drivers - The bad news is that means more questions:)
So the motors come with pre terminated wires - oddly a 2M motor and 3m encoder one. To extend the motor one I assume I just use CY cable ? The existing cable does not seem to be shielded.
But with most people using CY cable right from motor to cabinet, should I be cutting shorter and using a longer run of CY - or does the closed loop negate the need for shielding?
Same with the trial prox sensor I have, it's pre cabled with non shielded wire, so do people cut short and join?

Also before I ask the manufacturer - does it matter on the polarity the AC connections to the driver are - there are no marking or instructions on Phase / Neutral, assuming it won't matter ?

Ryan

JAZZCNC

22-04-2020, 09:22 AM

The good news - I now have 4 closed loop steppers and drivers - The bad news is that means more questions:)
So the motors come with pre terminated wires - oddly a 2M motor and 3m encoder one. To extend the motor one I assume I just use CY cable ? The existing cable does not seem to be shielded.
But with most people using CY cable right from motor to cabinet, should I be cutting shorter and using a longer run of CY - or does the closed loop negate the need for shielding?

I tend to cut the motor wires short and use shielded cable, but I have used them with the supplied cable and not had any problems. If it was me and you don't have any CY cable then I'd use it as is. You can always change it later if gives you trouble.
The encoder cable is usually shielded so it won't give you any trouble.

Same with the trial prox sensor I have, it's pre cabled with non shielded wire, so do people cut short and join?

Cut these short as possible and use shielded cable.

Also before I ask the manufacturer - does it matter on the polarity the AC connections to the driver are - there are no marking or instructions on Phase / Neutral, assuming it won't matter ?

Ryan

Doesn't matter it's AC alternating current so it bounces both ways so no polarity.

CNCRY

25-04-2020, 12:17 AM

Have my AXBB-E on its way now, so almost all the components - except for the VFD and spindle which I'll leave until I have a moving machine .
I'll be trying to get UCCNC to control one motor so I at least know it can be done (by me:) ) Linking it up to the Laptop is probably the only part of the electronics I hope goes easily with IT background..!
So I'm planning to use CAT6 cable I have already for STEP/DIR - do I just use the individual cores still twisted and leave in shielding for the run to stepper?
Also - what's the best method to join the fixed motor wiring /limit switches to CY cable - just solder and heat shrink over the top? if the CY doesn't run right to the motor (only 1/3 or so) is there any point grounding the shield at cabinet end?

AndyUK

25-04-2020, 09:05 PM

So I'm planning to use CAT6 cable I have already for STEP/DIR - do I just use the individual cores still twisted and leave in shielding for the run to stepper?

Assuming you mean between the AXBB-E and the motor driver rather than stepper, yes. Try to use differential signal connections if possible, one twisted pair for Step+ and step-, etc. Shield as much as possible, ground the shielding to the star ground in cab.

Also - what's the best method to join the fixed motor wiring /limit switches to CY cable - just solder and heat shrink over the top? if the CY doesn't run right to the motor (only 1/3 or so) is there any point grounding the shield at cabinet end?

That's what I did. Yes always useful to ground the shielding at the cabinet, otherwise it's just not doing much.

CNCRY

07-05-2020, 12:35 AM

Yep Andy - meant between the AXBB-E and driver!
Some more progress on the physical build - ballscrew covers are on and work as planned! and most of gantry done. Next is to tackle the motor mounts. Plan is to use the long 35mm shaft length to go through the mount without having to hand route out a pocket as others have.
I also managed to connect 4 steppers and get them moving via UCCNC with nothing going pop, so know electronics for movement in place.

28066
28067
28068

Reading Jazz's post elsewhere I realise I may have been confusing the X and Y axis all this time.oops. So stranding directly in front of the machine, I was calling left to right movement across the gantry Y and front to back X. So I have configured the dual ballscrew axis as X in UCCNC,
Reconfigure is just in software so OK, but can someone confirm I have been wrong, and X should be right to left (as per graph axis) and Y is dual axis. Probably good to know for a CNC machine:)

I'm also worried about the stand/table, When you put a decent force in the middle of the ply it flexes perhaps a couple of mm.
Initially I just needed somewhere to build it and didn't put lots of thought into the stand, thinking the machine frame will maintain it's structure. It's a wooden bench with ply top, I can do a fair amount to strengthen it up but - is this going to be a major sticking point? I see plenty of "desktop" type commercial machines out there which I assume people just stick on a workbench etc?
Really don't want to start having to get a frame welded if I can help it ! Ideas?

Thanks

pippin88

07-05-2020, 06:14 AM

Axis labelling can be however you want.

The convention is:
Standing in front of machine (as you will actually be using it)
Left to right is X
Front to back is Y
Up and down is Z

So yes like a graph.
CAD and CAM software is based on / defaults to this convention, so easiest to follow it.

Some people get funny and insist that across the gantry must be Y. Or the longest axis must be X. They are wrong. It's about how you draw the design / do the CAM.

JAZZCNC

07-05-2020, 12:22 PM

Like Pippin say's there is no wrong or right so long as the Controller and Cam match up. Otherwise it gets very confusing when watching the controller Vs machine movement. However the part will still cut correctly provided it doesn't hit the limits which often happens when people mix Axis and Cam up.

But to Answer your question then yes you did have it wrong way around to what is conventional, that being following the Cartesian coordinate system of X=Lft/Rht Y=For/Aft Z=Up/down

Looking good by the way, soon be making chips. then the trouble really starts...Lol

Andrewg

07-05-2020, 05:08 PM

Great progress, hope you will let us follow you to completion. Having read a lot of build logs here, it is so disappointing when a promising build tails off so you never learn if the design and approach had any merit! There are 5 builders with finished machines in the Gallery Post (http://www.mycncuk.com/threads/10066-Finished-builds-picture-menu) from 15 pagesx20 DIY build logs, so that is less than 2% that actually complete their machine and stick around long enough to share. It gives me pause, but you are giving me hope!

Not to criticise, but to show I am listening to the grey beards here, and want to copy much you have done:
I understand the frequent suggestion of having the gantry (X) separate and adjustable from the Y linear bearings for squaring up etc. You clearly still have access to your Y linear bearing screws, so adjustment is still available. However would turning the thick Y linear bearing plate into two, with the lower fixed to the bearings and the upper fixed to the gantry and then bolt and pin them when XY aligned make things more modular and adjustable?

AndyUK

07-05-2020, 07:22 PM

There are 5 builders with finished machines in the Gallery Post (http://www.mycncuk.com/threads/10066-Finished-builds-picture-menu) from 15 pagesx20 DIY build logs, so that is less than 2% that actually complete their machine and stick around long enough to share. It gives me pause, but you are giving me hope!?

That's just because people don't bother to post in the gallery thread. Whilst sure, there is an attrition rate, the success rate is a LOT higher than 2% in the build logs. I suggest you look at the last page in each one, you'll get a much better idea where they're up to.

JAZZCNC

07-05-2020, 07:26 PM

Not to criticise, but to show I am listening to the grey beards here, and want to copy much you have done:
I understand the frequent suggestion of having the gantry (X) separate and adjustable from the Y linear bearings for squaring up etc. You clearly still have access to your Y linear bearing screws, so adjustment is still available. However would turning the thick Y linear bearing plate into two, with the lower fixed to the bearings and the upper fixed to the gantry and then bolt and pin them when XY aligned to make things more modular and adjustable?

I'm going to answer this Andrew because many won't realize the difference and why it's important, well maybe I should say easier rather than more important.! Ryan might not even realize this yet because it's the first machine he's built.

The Biggest difference is that the 2 plate method doesn't affect the ball screw alignment to adjust the gantry square. However with the single-plate method when you adjust the gantry by loosening the bearing plate you apply a twisting motion on the ball-Nut because the ball-nut mount is attached to the gantry sides which also rotate with the gantry. This puts a bind on the ball-screw so it causes excess wear and lowers the speed.

This then means you have to make adjustments in some other area to bring the ball-screws perpendicular to the gantry sides and parallel to the rails. In a nutshell it's a right pain in the arse.!! . . . The twin plates take all this away.

CNCRY

08-05-2020, 12:24 AM

Thanks for the encouragement all, looking forward to having a moving machine soon..

Andrewg - I plan to keep the log going until the end, I'm sure there are much better build logs out there than mine, but I'm trying to show some of the smaller details/photos which made no sense to me when I started this process, and if it helps a few people along the way, then great as this forum has helped me loads so far.

As you say without seeing the fruits of someones design/pitfalls you can't be sure if it's a good one. As Andy mentioned though there are certainly more, like his which do continue.

On the dual plate, to be honest I did think of it earlier on, but at the time I was going in circles with the design and if I could physically make it so opted for a simple single plate. Jazz - I see what you are saying, essentially the ballscrew is fixed square with the frame, but the gantry may need slight squaring.

I'm hoping I can get slight adjustment if I have to go there, from shimming either ballnut or the gantry side/ballnut fixing. I have built in a very slight tolerance by using a 1mm thick piece of rubber between gantry side and ballnut fixing, which can compress 0.5mm ish to accomodate a slight twist.
So watch this space whether it works or not! If building new, I'd go for the 2 plate though.
Jazz - looking forward to your machine unveiling, maybe I can swap it with mine.. :beguiled:

So, wasteboard, just best to start with MDF and hold down clamps screwed into it to get started?

Kitwn

08-05-2020, 04:00 AM

I'm hoping I can get slight adjustment if I have to go there, from shimming either ballnut or the gantry side/ballnut fixing. I have built in a very slight tolerance by using a 1mm thick piece of rubber between gantry side and ballnut fixing, which can compress 0.5mm ish to accomodate a slight twist.

So, wasteboard, just best to start with MDF and hold down clamps screwed into it to get started?

I like the idea of deliberately designing with a built-in gap for a shim in certain places. There's no such thing as a -0.2mm shim however much you might want one when finally assembling the machine.

Having recently got away from just screwing clamps into an MDF spoilboard to using something a little more sophisticated I can honestly say it's worth the effort to do better from day one, even if it is just to get you started. One of the problems is the little dimples that form around the screw holes which must be removed before you can put another workpiece over them and it's a pain having to drill holes for where you want to fit the clamps every time. Re-using the same holes many times over isn't too reliable either. I let my machine drill a grid of holes in the plywood base board and then put M8 T-nuts underneath. A sacrificial layer of MDF goes over that and then drill again. I also put a row of hand-drilled holes at either end of the base board to hold any pieces which cover the whole cutting area of the machine.
You can always upgrade to a slotted aluminium base in the future if you need to.

JAZZCNC

08-05-2020, 10:13 AM

On the dual plate, to be honest I did think of it earlier on, but at the time I was going in circles with the design and if I could physically make it so opted for a simple single plate. Jazz - I see what you are saying, essentially the ballscrew is fixed square with the frame, but the gantry may need slight squaring.

Yes and no.
What you are doing when squaring the gantry is setting it perpendicular to the MASTER RAIL and NOT the frame. Infact forget the frame because unless you have built it perfectly square and aligned the Master rail perfectly parallel to it then you CANNOT measure from it. The MASTER rail is the ONLY reference point you work from.

So the ball-screw must also be perfectly parallel to the MASTER rail. Likewise, the Ball-NUT is set parallel to the gantry side.

So if you have set your ball-screws perfectly parallel to the MASTER rail, which you should have done. Then any angular adjustment on the gantry in respect to the MASTER rail means there must be an angular twist between the Ball-NUT and Ball-SCREW and this will cause excess wear and binding.

The goal is to get the gantry perpendicular in respect to the MASTER RAIL and the ball-SCREW perfectly parallel to the MASTER rail. This will then put the Ball-NUT perfectly parallel to the ball-SCREW.

When all this is done then this will show you how much Shimming and spacing is needed at various places around the machine in relation to the Frame. If you have built a perfectly square frame then it should be easy.!!

You may find the best place to shim to get square without impacting the screws/nut relationship too much is between the Gantry plates and profile at each side.
This is where building in lots of adjustment points comes into play and helps with setup and fine tuning, don't be surprised if this takes you many weeks to get right with lots of strip downs.

Edit: I've just done a quick sketch in SW to show how much just 1deg of misalignment translates across the length of a gantry or machine.
The measurement show the numbers except one and that is the twist of the ballnut in relation to the ball screw but the number is 0.70mm of twist which would wear a ballnut out in no time and cause lots of binding.

I'm hoping I can get slight adjustment if I have to go there, from shimming either ballnut or the gantry side/ballnut fixing. I have built in a very slight tolerance by using a 1mm thick piece of rubber between gantry side and ballnut fixing, which can compress 0.5mm ish to accomodate a slight twist.

The Rubber is BAD idea, your basicly building in Back-Lash. The rubber will allow it to float even under compression. Don't underestimate the forces and the amount of inertia that will be applied to ballnut which transfers to the ballscrew which pushes on the Endbearings which will be sat basicly on rubber engine mounts.!!

Jazz - looking forward to your machine unveiling, maybe I can swap it with mine.. :beguiled:

Oh don't be getting too excited I've not re-invented the wheel and the design is nothing special or new. It will just be built properly and strong compared to all the Cheap offerings on Ebay etc.

28070

Andrewg

08-05-2020, 06:39 PM

That's just because people don't bother to post in the gallery thread..
I was being a little provocative to see if anyone else might think to post their machines. Shoudl be a sticky, as it was a good idea. That some very capable people turn up with some great designs and get huge assistance here but fade away before getting a working machine does seem a pity.

I'm going to answer this Andrew because many won't realize the difference and why it's important.
Thanks, I am beginning to understand how alignment and precision in the build process is hugely affected by these design details. However with a single under-table ballscrew design, this would mean ideally the gantry side plates are not a single part...or are you suggesting the adjustment come at the top of the gantry plate with its connection to the X Gantry beam?

But sorry CNCRY, lets keep focused on your final hurdles to cutting! You are almost there.

CNCRY

09-05-2020, 11:55 PM

What you are doing when squaring the gantry is setting it perpendicular to the MASTER RAIL and NOT the frame. Infact forget the frame because unless you have built it perfectly square and aligned the Master rail perfectly parallel to it then you CANNOT measure from it. The MASTER rail is the ONLY reference point you work from.

So the ball-screw must also be perfectly parallel to the MASTER rail. Likewise, the Ball-NUT is set parallel to the gantry side.

So if you have set your ball-screws perfectly parallel to the MASTER rail, which you should have done. Then any angular adjustment on the gantry in respect to the MASTER rail means there must be an angular twist between the Ball-NUT and Ball-SCREW and this will cause excess wear and binding.

The goal is to get the gantry perpendicular in respect to the MASTER RAIL and the ball-SCREW perfectly parallel to the MASTER rail. This will then put the Ball-NUT perfectly parallel to the ball-SCREW.

When all this is done then this will show you how much Shimming and spacing is needed at various places around the machine in relation to the Frame. If you have built a perfectly square frame then it should be easy.!!

You may find the best place to shim to get square without impacting the screws/nut relationship too much is between the Gantry plates and profile at each side.
This is where building in lots of adjustment points comes into play and helps with setup and fine tuning, don't be surprised if this takes you many weeks to get right with lots of strip downs.

Edit: I've just done a quick sketch in SW to show how much just 1deg of misalignment translates across the length of a gantry or machine.
The measurement show the numbers except one and that is the twist of the ballnut in relation to the ball screw but the number is 0.70mm of twist which would wear a ballnut out in no time and cause lots of binding.

The Rubber is BAD idea, your basicly building in Back-Lash. The rubber will allow it to float even under compression. Don't underestimate the forces and the amount of inertia that will be applied to ballnut which transfers to the ballscrew which pushes on the Endbearings which will be sat basicly on rubber engine mounts.!!

OK so full honestly, in terms of the rail and ball-nut alignment, what I've done is to set the master rail using the thickness of the extrusion as a gauge and then use a fixed size block offset from the edge to ensure the rail runs parallel to the edge of the extrusion.
Then the "slave" rail is firstly set it the same way with not fully tight bolts, then run the gantry along it to ensure it runs smoothly along the rail and moves the rail very slightly to a final adjustment. (but in theory its the same offset from extrusion as master rail)
The axis runs smoothly with no ball-nuts attached at least!
Then the ballscrews were attached to extrusion using tooling plate spacer so in theory are fully parallel to the extrusion.
So yes clearly its not fine precision, and a fair amount is riding on the aluminium profile being to good tolerances which I guess is much harder on box steel build, but to see where I'm coming from I didn't know what a DTI even was was a couple of months ago!
So with that said, I'm hoping I can tweak things without any major changes to the machine.

The rubber part is only on the dual Y (formally known as X :) axis) ballnut. As per below in red. The bolts are still coupled into the ballnut mount, but I can easily replace that with 1mm aluminium shim.
28088

I've attached the motor mounts now so am going to run it tomorrow and see how it moves. Is it obvious it its binding , does it judder etc?
Then if shimming is needed use this on the gantry and Ball screw mounts.

How should you align the ballscrews vertically - I tried using a DTI on the rail touching the ballscrew but hard to where on the thread it sat. Or use a small block sat on the screw..?
Do people use the 3, 4, 5 triangle method to check square then adjust and set limits? As there are various ideas out there..

Will report back after running it - wish my luck :suspicion:

JAZZCNC

10-05-2020, 10:26 AM

The rubber part is only on the dual Y (formally known as X :) axis) ballnut. As per below in red. The bolts are still coupled into the ballnut mount, but I can easily replace that with 1mm aluminium shim.

Dump the rubber it's a bad idea for the reasons stated before. Shimming with aluminium is the better way to do it.
What you have done so far with rails etc and screws is fine so with shims you'll get it pretty much spot on with a bit of patience. My point in all the other post's was to high light the difference and why the extra plate makes things easier and with less chance of messing things up in other areas when making adjustments to gantry.

I've attached the motor mounts now so am going to run it tomorrow and see how it moves. Is it obvious it its binding , does it judder etc?
Then if shimming is needed use this on the gantry and Ball screw mounts.

Be Very careful when approaching the ends of travel because it's here where most get it wrong and it's very easy to bend the screws. At slow speeds the steppers will quite happily bend those screws like it's liquorish sticks and not complain about it.
At higher feeds any error here will stall the motors but still damage will be done.

When jogging near the ends watch the ball screw carefully and if you see it lift or bend then you have some misalignment. I CANNOT stress this enough move slowly and watch carefully because it only takes a second to bend the screw.!!

If you see any movement then loosen the end bearings and jog slowly towards the bearing, this will give you some idea of what's wrong. Most likely either a Gap will appear between bearing and frame or it will lift up/down. However it could be pushing the bearing into the frame which isn't so easy to see so pay careful attention to what the screw does.

How should you align the ballscrews vertically - I tried using a DTI on the rail touching the ballscrew but hard to where on the thread it sat. Or use a small block sat on the screw..?
Do people use the 3, 4, 5 triangle method to check square then adjust and set limits? As there are various ideas out there..

Will report back after running it - wish my luck :suspicion:

It's difficult on a long machine to use the DTI because the screw sags so you need a combination of straight edge and DTI. However it's often easier to go by feel and just loosen the end bearings, then shim or adjust as needed.
Between adjusting the Ball-nut mount and end bearings you will get it spot on eventually but don't be surprised if takes several setups, but the effort will be worth it because any binding robs power and cause excess wear so the extra time spent here pays off BIG time.

Regards testing for squareness then if you haven't got precision squares etc just initially use a good set square off the master rail to get you close. Then just cut a Large square, nearly the size of your bed and measure the diagonals with a good steel rule, NOT a tape measure. Tweak and adjust as needed then cut another square by trimming the last one.

CNCRY

10-05-2020, 11:33 PM

Very mixed day of results - finished most of the Z axis strengthen plates and connected the 2 Y motors up.
I ran each motor individually first with the ballnut uncoupled to check how it runs. The good part
The gantry motion on rails is very smooth and all good, and one ballscrew is running true (until squaring anyway!)
Using a digital square the gantry seems good enough to progress to cutting a square to determine further.
The bad bit - the other ballscrew is definitely bent, not 100% if it arrived that way but much more likely it's a result of drill testing or something else I did! Some swearing involved and am waiting to find out if Fred can amend my spindle order...
Advice for anyone in the research stage - plan some budget for screw ups!
I connected both screws up for a short time just to test the Axis slaving - and it was cool to see my creation moving via the laptop finally!

Now waiting on replacement parts I'm going to fit and wire in the limit switches. This should be simple but the diagram which came with the switch confused me..
Can someone tell me is this right? I thought I understood it until I see the black cable on the switch diagram shows 6-36V while "out" on the AXXB manual shows it at 0v?

AXXB manual image, switch diagram and my understanding of it.
28105
28106
28107

Kitwn

11-05-2020, 02:38 AM

The black wire is the output of the sensor. It is pulled up to the supply voltage by an internal 10k Ohm resistor until the output transistor conducts and pulls it to near zero volts. 'Normally Open' (NO) means the transistor is not conducting (output pulled high by the resistor) until the sensor is triggered. 'Normally Closed' (NC) means the opposite. Only NO types can be connected in parallel as shown in your diagram, any single output pulled low will pull the others with it and the input to the controller. NC types (which you have according to the diagram) must be connected in series since, if in parallel, all the outputs will be normally low and the ONE that tries to go high will be held low by the others. Unfortunately your AXXB manual image does not explain that but the text should.

EDIT: Your controller software should include a configuration for selecting whether your sensors are NC or NO. If you get continuous limit alarms then that my need to be changed.

CNCRY

11-05-2020, 11:38 AM

Ok so they are NC type to cover the issue of broken wires etc.
So the black wire will normally be at supply voltage until limits are hit.
I'm planning on wiring each to its own limit input on axbbe as there are 6 available, leaving a couple for probes and future use.
So imagining just one switch in my diagram above , l1+ will always be 24v and l1- would be at 24v normally unless switch triggered.
Is that right ?
Thanks !

Kitwn

11-05-2020, 01:11 PM

Other way round! NC will normally be at ground voltage (Normally Closed to ground) until triggered. "Normal' means you have NOT driven the machine to it's limit and it is continuing to cut material as intended. This gives you protection against broken wires as an open wire shows up as a high voltage if your controller has it's own pull-up resistors and the machine stops. Failure of a NO connection only shows up when the limit switch fails to make the ground connection required and your gantry crashes through both the limit switch and the end wall of your shed.

My personal preference is for one switch per input as you are planning. NC is best as explained above but NO is more commonly available, presumably because of the ease of parallel connection.

CNCRY

11-05-2020, 03:46 PM

Thanks kitwin , think that makes sense now , will connect one up to UCCnc and test.
Looks like too late for replacement ballscrew from Fred , can any 1610 ballscrew work with the SFU nuts ? Or is the fit not right unless factory paired ?
E.g if I get a gten machined one will it work with SFU ballnut from Fred...

CNCRY

16-05-2020, 12:28 AM

Replacement ball screw ordered now, so will report back if SFU nut fits well.
I tested the limit switches and all working as they should - they even light up:) Thanks Kitwin !
The final piece of the wiring puzzle (until I add things!) is the spindle, while I'm awaiting delivery I want to make sure I know what I'm doing and this is the bit I've been avoiding:)

High level, do I connect up power and the spindle, then go in and set the PD* values , power down and wire up to AXBB-E , then go in and test?

Wiring
The wiring I have based on CharlieRams thead is

28148

Does this look correct ? In that thread Charlie couldn't get 0-10v to work so stuck with 0-5v. Any issue with just leaving the jumper on AXBB on so its 0-5V and setting PD070 to 1 to match the 0-5V control?

Also I'm thinking why is FOR/REV needed, I can't think of a use now for reverse so can I just link DCM and FOR ? Or will I lose the ability for UCCNC to turn on/off the spindle and e-stop?

I'm planning to use 1mm CY 4 core cable - seems like there are differing opinions here, but I'm trying to minimize cable size and 1mm should sustain a max of 8Amps rating and the spindle will use 5A or less in use as Jazz has measured, so gives so overhead for voltage drop etc.

PD Values
This is where I'm a bit stumped, maybe the manual will explain more (probably not) but some blogs etc people set only a couple of values while the sticky here suggests loads.
Is the sticky still correct as of 2020?
Control:
PD001/002 = 1
Frequency:
PD005 - 400
PD004 - 400
PD003 - 400
PD006 - 2.5
PD007 - 1.20

PD008 - 220
PD009 - 15
PD011 - 120
PD014 - 5
PD015 - 10
PD044 - 2
PD045 - 3
PD072 - 400.00
PD143 - 2
PD142 - 7
PD144 - 3000, factory setting is 1440 ->3000 gives correct RPM of 24000 at 400hz

PD070 (optional to 1 for 0-5V rather then 0-10v)

Thanks !

Kitwn

16-05-2020, 03:43 AM

One of the most important parts of installing your spindle is soldering on the connector properly. I have a sneaking suspicion that many of the 'my VFD blew up the first time I switched it on' complaints have their roots in this having been the first time the relevant person had soldered a plug onto a cable. This is a very expensive way to learn from your mistakes!

JAZZCNC

16-05-2020, 10:23 AM

High level, do I connect up power and the spindle, then go in and set the PD* values , power down and wire up to AXBB-E , then go in and test?

Doesn't matter really you won't hurt anything either way. I just connect everything up then set the settings but I've fitted 100's and confident so just do what you feel most comfortable doing. There's no right or wrong way provided you DONT wire it when powered up.! (like I often do.:cower:)

You can actually power up the VFD without the spindle connected and enter the settings on the bench if you prefer, I often do this before fitting into the control box's on machines that are fiddly to access or I'm waiting for other stuff so do it to save time later.

Does this look correct ? In that thread Charlie couldn't get 0-10v to work so stuck with 0-5v. Any issue with just leaving the jumper on AXBB on so its 0-5V and setting PD070 to 1 to match the 0-5V control?

Also I'm thinking why is FOR/REV needed, I can't think of a use now for reverse so can I just link DCM and FOR ? Or will I lose the ability for UCCNC to turn on/off the spindle and e-stop?

I'm planning to use 1mm CY 4 core cable - seems like there are differing opinions here, but I'm trying to minimize cable size and 1mm should sustain a max of 8Amps rating and the spindle will use 5A or less in use as Jazz has measured, so gives so overhead for voltage drop etc.

I find 0-10V gives better scaling and more accurate speed than 5V but both work ok and neither is very accurate but for most machines, a few 100rpm tolerance is perfectly fine.

Only connect FOR because these spindles are not designed to run in Reverse, they will run in reverse ok electrically but the collet system isn't designed to run in reverse and will unscrew it's self if put under heavy loads.

1mm/2 cable is perfectly fine provided you are not running very long lengths. Again I've built dozens of machines that are fitted with 1mm and never had any issues.
Like KIT mentioned it helps with the spindle connector because space is very tight. Take your time here and use heat shrink on the pins so they can't touch. Also and this is THE MOST IMPORTANT make sure you fit a Cable strain on the bracket or Z front plate to hold the cable so it takes the pressure off the connector. This is THE single biggest reason why spindles blow up which ties in closely to KIT's poor wiring job advise, fail to do both correctly and it's just a matter of time untill BOOM.!!

CNCRY

22-05-2020, 11:50 AM

AndyUK

22-05-2020, 12:17 PM

Vfd powered up on bench to check settings, most were factory set, such as 400 frequency and earth pin connected to body .
Quick question on pd007 , factory is set to 0.5 and 1.2 recommended , minimum frequency . Can anyone confirm this is correct as some forums etc use very different values here.
Spindle is a gdz80 2.2
Thanks

I use 1.2 on my 2.2kW 400Hz generic Chinese water cooled spindle.

Ignore the below sentence, I was remembering information about PD011, which is similar. Might still be the reason?
I believe the variation on this one is between if its water or air cooled. You shouldn't run the air-cooled version below a certain RPM (i'll probably miss quote it here if I try to remember) without it overheating, so that might be the cause of the variation in recommendations you see.

One thing Jazz recommended when he saw my settings which were mostly coppied from the sticky, was to increase the acceleration and deceleration times, PD14=5 PD15=10.

CNCRY

22-05-2020, 12:26 PM

AndyUK

22-05-2020, 12:45 PM

No problem.

Been doing a little more reading, looks like PD007 and PD010 work together to define the minimum point on the V/F curve, so in essence it looks like its a way to tune how much torque you get from the spindle at different speeds? Either way, 0.5 or 1.2 should work to get you started.

It might just be paranoia, but when I turned on my spindle I had a second person around who knew how to isolate the power supply. Just incase I'd messed up one of those phases and was about to make the whole thing a bit sparky. I then checked the spindle body with a multimeter while it was running, and sheepishly tapped it with the back of my hand to make sure all was well.

JAZZCNC

22-05-2020, 01:04 PM

Thanks Andy, I'll stick with that value for now . I had pd014 /015 set to default of 60/90 ! I read somewhere that 015 is ignored unless you have braking configured but don't quote me on that ! I set pd014 to 10 to give a decent spin up time but may reduce in future if all goes well. Next to connect spindle !

PD015 is ignored if not using DC braking and if you have it too low then you will get over current errors because the spindle cannot stop in time to satisfy the time parameter and dumps a load of current trying to do this.
The settings I gave Andy work for 99% of spindles, only if you have ATC will they need to be changed. Pd007 can be Zero if you like it won't hurt but just leave it at default.

CNCRY

22-05-2020, 01:51 PM

1 other question! my VFD has an earth terminal (pin9) next to motor UVW and 2 other screws not in the main block with earth symbol. I assume the pin 9 is for SPINDLE earth ? And the other one for incoming mains.
Edit - sorted pin9 to connect both incoming earth and spindle earth ,(pin4)
Plus shielding to separate star point outside vfd.
Thanks

Kitwn

22-05-2020, 02:45 PM

If you do go for a slow speed-up on the spindle and let the G-code start it just before the cutting begins you may need to add a delay to let it come up to speed. I've found this necessary using CamBam and LinuxCNC (though I cannot remember exacltly what my acceleration setting is, I'm sure I took the advice on this forum). I manualy add a line 'G4 P6' just after the spindle start line to add a 6 second delay.

CNCRY

23-05-2020, 08:12 PM

Spindle wired up and powered on, very carefully !
Press Run and it runs ok but for some reason goes straight to 24000 rpm and the front speed control does nothing?
I tried setting Pd002 to both 0 and 1 but made no difference. The "J1" jumper is also shorted pin 2 and 3 e.g VR not VI.
The spindle spec sheet also says pd070 should be at 1 which it is.
Am I missing something ? Otherwise 'll try UCCnc control instead and see if that works !

CNCRY

24-05-2020, 10:48 PM

Still no speed control on the spindle when connected to AXBB-E
Cabled as above with VFD>AXBB-E
FOR > O2
DCM > 24V0
VI > AO1
ACM > 5V0 (power out)

28197

When I enter in MDI M3 S2500 - the O2 pit diagnostic lights up and spindle FOR lights up and stops flashing, like this:

28198

But Speed sits at 0!
I checked the voltage between AO1 and 5v0 at S2500 and it seems to be 0 so possibly the issue.

Here are my settings

28199

I noticed "SPINDLE CW" light comes on in UCCNC diagnostics too.
Am I missing some config here or something obvious as I'm stumped!

Thanks
Ryan

CNCRY

25-05-2020, 08:36 PM

Sorted it ! It's not obvious in the documentation but there is an extra I/0 configuration screen where PWM channel has to be set to 1 not default of 0.
Oddly taking the jumper off the Axxb-e still won't output 0-10v, so ended up leaving VFD PD070 @ 5V control too.

Doddy

25-05-2020, 09:18 PM

Nice catch. I did have a quick look through the AXBB manual buy didn't spot that (the port/pin config looked suspicious but I've had Chinese motion controllers that ignore port/pins before so not entirely unrealistic). Not got/tried the AXBB myself - just keep your jumper setting in mind - unlikely but possible it'll mode on a reboot (your behaviour might be different next time you power-up... or maybe not), Peculiar that it doesn't behave as expected. You've set the max-spindle speed correctly, of course?

CNCRY

25-05-2020, 11:28 PM

For anyone's reference in future this is the setting:
28204

Initially I set the spindle min to 5000, max 24000 which I assumed meant it would just not allow a command below S5000, but figured out that meant 5000rpm = 0v, so when I set 10000rpm I would get 7500ish instead! So set min to 1, max 24000 and all good (to the nearest few hundred anyway).

Playing around in UCCNC reminded me of a couple of other things
- is it worth setting max velocity and acceleration at this point, set to 2000 units, so 20m/m which I expect is faster then it will go.
- Is there any worthwhile tuning of steppers needed - these are the hybrid steppers so slightly less common. I see there are 4 switches which can be used to set pulse/rev but no idea if these are worth changing?
Or maybe I'm just thinking up ideas while waiting on parts:) Feels like I'm on the home stretch now, just need to figure out my workholding and spoil-board which doesn't eat up the Z distance.
I also couldn't find an obvious answer on this - can I use normal 1/2" router bits in the spindle or does everyone use endmills? Obviously something like a Lock Mitre bit would be a bad idea, but the simple 2 flute straight bits, chamfer etc..

JAZZCNC

26-05-2020, 10:16 AM

Playing around in UCCNC reminded me of a couple of other things
- is it worth setting max velocity and acceleration at this point, set to 2000 units, so 20m/m which I expect is faster then it will go.

2000 is the units ie: mm or inch value so if you want 20m/m it needs to be 20,000 not 2000. Read below and it will make more sense, if not just ask.

The velocity and acceleration are very important and you can't just womp them up and leave it at that because you'll just get stalling motors.
This is the bit that you'll see mentioned as motor tuning and it's a balance between velocity and acceleration, If you increase one it will affect the other at some point and you'll have to decrease one of them.

Every machine is different when it comes to tuning the motors because of friction and mass, voltages etc, so it's very much feel way your way thru and lots of little tweaks.
Start low on both at say 4000mm/min on velocity and 500 on acceleration. Then adjust just the velocity until the motors stall, then reduce the amount by 25%, then do the same with acceleration. This will give you a base line and nice stable machine, you can tweak it up from there but again only adjust one at a time and test.

- Is there any worthwhile tuning of steppers needed - these are the hybrid steppers so slightly less common. I see there are 4 switches which can be used to set pulse/rev but no idea if these are worth changing?

Well first hybrid steppers are common as muck, probably the most common stepper on the market and it means NOTHING. I see this a lot that people get blinded by jargon and think that the word Hybrid means they are something special when all it means is they can be wired in several ways making them an Hybrid of several types of steppers.

Again these switches are very important as they set the micro steps, infact THE most important bit because if you don't know this setting then you can't possibly set the correct Steps Per unit value in UCCNC and you won't get the correct amount of movement. It also affects the motor tuning because the higher these settings then the motor acts differently, going too high can give negative results as they are very close relationship with motor tuning and the system as a whole.

There will be a chart on the stepper case that gives different micro step options and will tell you the positions those switches need to be set for each micro step amount.
Set them up to give 1600 micro steps. There is no need to go higher as it starts to give negative results.
Now you take this figure and do a calculation for the steps per unit value that you enter into UCCNC. Divide 1600 by the ball-screw pitch and any ratio you may have. So if it's direct drive with 10mm pitch then 1600/10=160 for the steps per.

This will give the correct movement, the Steps Per setting is a none negotiable setting and you can't just use a random number, it must be calculated from the Drive settings. ball-screw pitch and any ratios applied to it.

-I also couldn't find an obvious answer on this - can I use normal 1/2" router bits in the spindle or does everyone use endmills? Obviously something like a Lock Mitre bit would be a bad idea, but the simple 2 flute straight bits, chamfer etc..

You can use what ever you like, stick a pencil up it if you like. Also no reason why couldn't use a Lock mitre bit provide it's not like 6" and 3kg in weight. I regularly use a 70mm surfacing bit which is bigger than a lock mitre bit.

I often use my old worn out end mils that I've used on aluminium for cutting wood as they are still more than good enough for hogging out wood and often I've only worn the first 4-5mm out and I cut much deeper in wood. I then use a decent end mill for the finish passes.

Neale

26-05-2020, 10:28 AM

I also couldn't find an obvious answer on this - can I use normal 1/2" router bits in the spindle or does everyone use endmills? Obviously something like a Lock Mitre bit would be a bad idea, but the simple 2 flute straight bits, chamfer etc..

One way to look at this is, "Would I use this cutter in a handheld 1/2" router at 26000RPM?" Or even a 1/4" router. If the answer is yes, then go ahead with it in a more powerful spindle with much better control!

Doddy

26-05-2020, 07:02 PM

To be fair - a good many hand held routers are in a similar power band to the usual spindle, and similar RPM. I wouldn't sweat too much. Common sense applies, of course.

CNCRY

27-05-2020, 12:34 AM

Thanks all - I did see people using them but just wondered if there was something I'd missed before using standard bits. Seems like a really obvious question now:)
The stepper drivers were set by default at 1000 according to switches so have changed the switches to 1600 in the table as recommended.
I was thinking the "units" referred to cm - as UCCNC defaulted to 200 steps per unit, I took this as meaning 200 steps @ 1.8 degrees to make 1 revolution which would equate to 10mm of motion, so a unit being 10mm. I guess I was calculating the wrong way round!
Does jogging use the same velocity settings - as jogging seemed to be about 10m/min which seems about right , even with microstepping on drivers set to 1000 and steps /unit at 200?
With the hybrid steppers I mean that many build logs on here and other forums use "standard" steppers without an encoder, and wasn't sure if mine having encoders that had any bearing on the tuning. Assuming it being a closed loop the controller never knows any different anyway.
Once I get the replacement ballscrew and right size drag chain I'll do some more testing and tuning.

JAZZCNC

27-05-2020, 12:17 PM

The stepper drivers were set by default at 1000 according to switches so have changed the switches to 1600 in the table as recommended.
I was thinking the "units" referred to cm - as UCCNC defaulted to 200 steps per unit, I took this as meaning 200 steps @ 1.8 degrees to make 1 revolution which would equate to 10mm of motion, so a unit being 10mm. I guess I was calculating the wrong way round!
Does jogging use the same velocity settings - as jogging seemed to be about 10m/min which seems about right , even with microstepping on drivers set to 1000 and steps /unit at 200?
With the hybrid steppers I mean that many build logs on here and other forums use "standard" steppers without an encoder, and wasn't sure if mine having encoders that had any bearing on the tuning. Assuming it being a closed loop the controller never knows any different anyway.
Once I get the replacement ballscrew and right size drag chain I'll do some more testing and tuning.

Regards 1000Ms and 200units in uccnc then even thou it's traveling at 10mtr/min doesn't mean it's moving the correct distance. The test would be to tell it to move 10mm, which in your case with settings above and 10mm pitch it would move 20mm.
The closed -loop won't make a jot of difference because it's been told to move 2000 pulses which dutifully does, it knows nothing about the 10mm and only does as it's told moving a set amount of pulses based on the Steps per unit setting.

With that setting of 1000ms then you should enter 100 in steps per and it will move at 10mtr/min(or more) but only half the distance.

The velocity is the Max velocity of the machine and is used by everything, however you will see it slow down at times when 2 or more axis are traveling together because the controller will control the speed of the faster axis so all axis arrive at same time.
Jogging individually each axis will move at full velocity set in motor tuning if set at 100% jog rate.

CNCRY

28-05-2020, 09:26 AM

So my replacement ballscrew arrived and it's 15mm O.D. it came with a ballnut but the screw is a different weight now . The existing one on dual axis is 16mm .
Seller is saying it's nominal diameter as it's a ballscrew . is it usable or will the weight difference and inertia etc compared to the other axis side make it not worth it...

AndyUK

28-05-2020, 10:11 AM

Not ideal, but my gut feeling is if the pitch is okay, it should be workable.

It will make one motor work marginally harder than the other, but probably not even noticeable?

CNCRY

28-05-2020, 11:03 AM

JAZZCNC

28-05-2020, 03:01 PM

Thanks Andy , just trying to decide whether to try and straighten bent screw , use a diff weight screw or get an exact replacement from Fred ! Bit of a pain really but with the effort gone in so far I do want it to be right . Not sure I have the setup to straighten it but not much to lose on that !

Have you tried to run the machine with the bent screw yet.? If not you may be surprised how much of a bend can be tolerated. Esp on a machine that isn't massively long.!!

Did the 15mm screw come from Fred.? . . . I've never seen a 15mm screw that's sold as a 16mm.!

CNCRY

28-05-2020, 03:13 PM

AndyUK

28-05-2020, 05:08 PM

The seller is saying "For a ballscrew the external outer diameter is a totally unimportant dimension, because it connects to the ballnut with balls" which kind of makes sense but why call it a 16mm screw then. And Fred's are 16mm within 0.01mm ...

If you're still within 14 days very easy to turn around and tell them you don't want it if you've changed your mind. They've advertised as 16mm, so it isn't what you ordered... Doesn't matter if they think that is important or not.

JAZZCNC

28-05-2020, 08:56 PM

I did run it slow and seemed ok but worried it would wear the ballnut fast .
Nope that ballscrew was the only one not from Fred , I ordered it in the EU to save time but wishing I hadn't now!
The seller is saying "For a ballscrew the external outer diameter is a totally unimportant dimension, because it connects to the ballnut with balls" which kind of makes sense but why call it a 16mm screw then. And Fred's are 16mm within 0.01mm ...

Yes didn't think it would have been as Fred's screws are also ways within 0.01 of specified like they should be. Send it back would be my suggestion and fit the old one if it's only slightly bent. Then buy a new one from Fred if it gives you any grief.

CNCRY

05-06-2020, 12:09 AM

Will post some progress photos soon, but have now pretty much completed the wiring and physical build.
Cable chain finally arrived from China so the (crazy) amount of wiring is now running back into the control box and 4 separate limits wired in.
I setup the limit and tested jogging into them and all good there. Machine is running at 4m/min currently as Jazz suggested, until I tune it further.
I ended up straightening the ballscrew mostly, using the advanced method of compressing between some hardwood and rotating it. But now it's back in the mount it seems to be running pretty well at 100% jog speed. I think my drill test made it seem a lot worse plus there was some slight misalignment of the motor coupler. I do notice the X axis is very smooth even compared to the dual Y.
My next test after jogging was homing.

So X and Z - moved along, hit the limit stopped and backed off - great.
Dual Y - both axis moved towards limit, one side hit limit switch fractionally before the other, then the one which hit the limit seems to keep going and the other side never hits the limit, so the gantry starts to go off square and hit the ESTOP before it breaks the gantry!

I have both axis set to have homing to the negative limit and 2 separate limit pins set so not sure what is going on here.
When I jog the axis slowly into limit it hit both pins and stopped, both flag up in UCCNC as hit.

Before I post on UCCNC forum am I missing something obvious here in the homing sequence for dual axis?

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CNCRY

07-06-2020, 10:26 PM

Sorted - the limit switches for each side of the Y axis did not match the drivers, so when one switch triggered it stopped the opposing side motor. Fine while I was testing limits, not so much for homing operations!
Homing all working now. Just waiting on some ER20 collets now and hoping to make first cuts very soon.
So far I just have a ply bed as I figure I'll probably have a few accidents, then thinking to use an MDF bed with threaded inserts fitted from underneath every X cm to allow fixing from above without using screws.
Need some practice before going for a more expensive material for the bed!
Still overwhelmed by the amount of settings in CAM around ramp speeds, lead in speed, plunge speeds, feed's etc and how much is OK to leave at default and how much to change.

Kitwn

07-06-2020, 10:38 PM

Good you've got that sorted.

I've recently installed an MDF baseboard with M8 threaded inserts at 100mm intervals. It seemed a sensible spacing at the time but I'd go for 75mm if I was doing it again. For reasons that don't matter here the holes are not quite aligned to the 100mm multiples on the X and Y co-ordinates of the machine which slightly complicates designing cutting layouts when I want to fix the blanks directly to the table rather than use clamps.

Kit

CNCRY

11-06-2020, 11:29 PM

Hi All, as promised a few photos of my first "completed" build. I've finally managed to make my first cuts, press go and leave my creation to cut something which is a great moment after starting from almost zero knowledge!
First CAM lesson - Fusion 360 doesn't automatically add D.O.C so plunged the full 10mm and I had to reduce to 20% Feed Rate.
Big thanks to everyone who has answered various newbie questions on here over the past 6 months, Jazz, AndyUK, Kitwin, Doddy, Clive and others !
I still need to level my wasteboard and tram the spindle but It's not far off. My 100mm x 100mm square was 0.05mm or so out, but then the bit was a cheap chinese router bit which claimed to be 1/2" but wasn't exactly.
Aside from sorting a better wasteboard I really need some dust extraction, especially testing on MDF.
Are there any particularly good dust shoes people can recommend - I only have a small distance at the bottom of spindle as the mount is low so something compatible would be good.
I have a basic metal drum type dust extractor - fine for normal woodworking but its loud and I doubt rated for continuous use. What do people use for quieter solutions?

PS. Don't judge me on my messy wiring:) Lucky I have a diagram
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Ryan

JAZZCNC

11-06-2020, 11:44 PM

Well done Ryan, and let the fun begin.:yahoo: .....you'll kill lots of cutters and material at first but that's just part of the learning we all have to go thru.
Don't be surprised if you have to keep tweaking the machine for a few weeks as it settles down. It's a good idea to run it for a couple of weeks or so then go over it top to bottom checking screws and connections etc, esp motor pulleys/couplers. (Dab a bit of paint on the shafts as a quick visual aid for slippage)

Now you just need to cut the Aztec calendar acid test and we'll let you in the Aztec Gang... :toot:

CNCRY

12-06-2020, 12:02 AM

Doddy

12-06-2020, 12:04 AM

First CAM lesson - Fusion 360 doesn't automatically add D.O.C so plunged the full 10mm and I had to reduce to 20% Feed Rate.

All good stuff. Re. Fusion - are you sure?, I'm on the wrong computer atm to check but there's usually a flag on the 3rd-or-4th tab with something like a "multiple heights" or similar name that allows a DOC to be specified. From memory...bad memory.

Kitwn

12-06-2020, 02:09 AM

PS. Don't judge me on my messy wiring:) Lucky I have a diagram

In my experience a lot of 'neat' professional wiring is actually messy wiring hidden in swanky looking trunking. Enjoy your new toy.

Kit

JAZZCNC

12-06-2020, 08:29 AM

Cheers Jazz - will give it a once over and remember I actually need to grease it..
Ha, well I've managed to bend one bit so far - luckily a cheap one, but amazing how easily the 5.5Nm bends it like a twig..!
Maybe I'll give the Aztec a go in MDF first - does that count:)

Wait until 5.5Nm rips the material from the bed and throws across the room or you program 100 instead if 10 on a Z move and in blink of an eye it's punched a nice neat hole thru your bed(not that I've done this before.:whistle:)

Regards Aztec and MDF then don't do a small one in MDF because it doesn't hold the detail good enough. You need a harder material that holds nice edge for smaller ones like 6" to get the full affect and see all the tiny details.

CNCRY

18-06-2020, 11:14 PM

I've been cutting and engraving a few test pieces, mainly MDF or softwoods while I learn more on the CAD and tool-paths. And remembering to zero Z after a tool change.!
First "proper" project is to make a dust shoe - I figured it'll end up slightly cheaper then buying and be interesting working with cutting plastic.
So the one I'm making is the Avid CNC one, using magnets to allow removal of the brush https://www.cncrouterparts.com/universal-cnc-dust-shoe-p-396.html.
Helpfully they provide the fusion design with parametric value, so it can be edited to hose/spindle size. I'll be making it out of HDPE plastic.

I'm also thinking about trying some aluminium and wondering do I need a mister, or at least air blast to do anything more than minimal work in aluminium? Or would the dust collection remove chips enough?
I have one of these basic eBay misters https://cdn.thingiverse.com/assets/f4/bb/36/49/ef/featured_preview_CNC_Mister_Collar_02.png but no compressor yet as most things I read suggest you need a fairly decent tank size to prevent overheating.
I also looked at silent "dentist type" however the price goes up a fair amount!
Any advice from those who have "been there and tried that" :)

RobC

19-06-2020, 12:18 AM

You dont 'need' to have anything for aluminium providing you don't slot too deep or you risk welding to your tooling, it does help massively to have chip evacuation but I get away with it just!

Clive S

19-06-2020, 07:42 AM

I'm also thinking about trying some aluminium and wondering do I need a mister, or at least air blast to do anything more than minimal work in aluminium? Or would the dust collection remove chips enough?
I have one of these basic eBay misters https://cdn.thingiverse.com/assets/f..._Collar_02.png but no compressor yet as most things I read suggest you need a fairly decent tank size to prevent overheating.
I also looked at silent "dentist type" however the price goes up a fair amount!
Any advice from those who have "been there and tried that" :)

Different grades of alli will cut differently. 6082T is generally ok or 7 series and cast alli . just spay a bit of WD40 or equivalent helps but if you get the feeds and speeds correct it will cut fine.

CNCRY

19-06-2020, 01:05 PM

I have some parts I'd eventually like to make which would involve cutting out/slotting 25mm or so deep. Would a small compressor assist at least , even if it ends up filling the tank 50% of the time, but is quiet when it does it !
Something like https://www.lawnandpower.co.uk/product/hyundai-hy7524-52cfm-1hp-24-litre-oil-free-direct-drive-silenced-air-compressor/?gclid=CjwKCAjw_qb3BRAVEiwAvwq6Vq4hkA6dkFuWsHX_3dv tDHIJNZ7yDVTiqXXviUTmecm5zWLu4UEkdxoC-hwQAvD_BwE

I'll do some experimenting soon !

Doddy

19-06-2020, 04:23 PM

I had a Peak Scientific compressor - around 25l, dentist job, silent as anything, and pretty useless for mist-cooling. With a low CFM and a small tank, it exhausted quickly, even just with a hand-help airgun where I could regulate things myself. The main problem was the low duty-cycle for the motor - after an hour cutting, and cooling, the compressor would overheat and cut-off until it cooled... that's when the WD40 would come out and smoke-out the shed.

Here's a hint: Unfortunate, but true, there's an awful lot of pubs going to the wall. I recently found a 50l (not much bigger), but similarly silent and 100% duty cycle compressor from a clearance of a brewery that had gone down the swanny. I'm not proud of taking advantage, but 40 quid later and I'm giving the old compressor away. Keep an eye on the auctions.

CNCRY

06-07-2020, 01:04 AM

Been busy this week sorting out a ply threaded board, used 75mm spacing as suggested rather then 100+
I then have a second piece of MDF on top with holes but its not glued, just bolted down at various points currently.
The M8 bolt fixing is working pretty well, using simply bolts and washers to clamp the edge, however without gluing the MDF spoil board I can't surface it accurately which is an issue, just wondering if there is a better alternative to gluing ... screwing with slightly countersunk holes?

So much to learn about fusion 360 CAM still - managed to make my first aluminium part! Simple pocket toolpath and cutout, but I was pretty happy with the finish, not that I have much to compare to, just it did it first time with no issues.
Couple of sprays of WD-40 but used 17,500rpm with 1mm DOC, 6mm 2 flute end mill.

It's a um... coaster?

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May give the Aztec calendar a go Jazz , is there any specific high quality STL file you have for fusion 360 - as a few various ones out there I've found?

Also, does anyone have any suggestions for the best way to face a surface that fits in an ER-20 collet? I've seen flycutters etc mentioned but most are too large - any recommendations?

Ryan

CNCRY

18-10-2020, 11:02 PM

Hi everyone,

After a couple of months with minimal time to spend on the CNC, finally getting back into it. Learnt lots but still much more to learn, as is always the way..

So one thing I hadn't fully thought out in the design is how to grease the Z bearing blocks. The nipples are in the right place (must avoid obvious jokes here..) but the grease gun "Nozzle" wont fit in the space to engage properly.

So I'm thinking of using the side inlets - only recently realised that was possible.
Hiwin say you should carefully pierce the side inlet with a hot metal rod to avoid chips in the bearings. Do you then have to insert a new grease nipple (can't see a thread) or is there a different type of nozzle available you can just pressure fit and fire in the grease. I can't have a permanent fixing as it would hit the side plate.

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Thanks
Ryan

guciTaums

20-10-2020, 03:35 PM

I would like to know what kind of forum is this? phpbb? Guci

Neale

20-10-2020, 04:58 PM

Take a look at the very bottom of the screen.

CNCRY

27-11-2020, 01:07 AM

Thanks Kered - sounds like a cost saving option, although I'm not sure I'd trust myself with self made high pressure tanks. Maybe one to add to the list to try:)
I've been spending most of my time on wood recently so not progressed the mist coolant plan at all as yet!
Top of my list for improvements/purchases now are

- handheld wireless controller for UCCNC (as sticking the laptop on the bandsaw table while I set part zero isn't ideal)
- Improve the table/spoilboard combination.

Currently I have a sheet of 12mm ply on top of the base's cross pieces which is drilled and inserted T nuts. Problem is sometimes they drop out the bottom as the bolt knocks them out when trying to fix something , which is a pain. Plus 12mm ply isn't the most stable material.

Current options - either some aluminum T-slot, steel t-slot , pre drilled and tapped steel grid plate or buy a sheet of aluminum then surface and use the machine to "drill" a grid of holes.
I don't have much Z height so needs to be <20mm maximum.

Anyone tried these or have any comments?

Thanks!

JAZZCNC

27-11-2020, 05:41 PM

Top of my list for improvements/purchases now are

- handheld wireless controller for UCCNC (as sticking the laptop on the bandsaw table while I set part zero isn't ideal)

When your ready get in touch as I'm now stocking Controllers etc from CncDrive and have just got one of the UCR201 wireless controllers to test and I can tell you it's an amazing bit of kit. One of the best I've ever used.

Currently I have a sheet of 12mm ply on top of the base's cross pieces which is drilled and inserted T nuts. Problem is sometimes they drop out the bottom as the bolt knocks them out when trying to fix something , which is a pain. Plus 12mm ply isn't the most stable material.

Current options - either some aluminum T-slot, steel t-slot , pre drilled and tapped steel grid plate or buy a sheet of aluminum then surface and use the machine to "drill" a grid of holes.
I don't have much Z height so needs to be <20mm maximum.

Anyone tried these or have any comments?

Thanks!

I've used just about every method and my personal favorite by a long way is the Matrix grid of tapped holes. It gives the most flexibility and if combined with a few strips of T-slot in strategic places there's not much you can't hold.

I wouldn't buy a rolled plate and surface it thou as it releases stress and moves around, ground cast tooling plate is much better and doesn't move around when you drill/tap it.