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

In the video is your indicator tip running along the other rail - not the rail you're pushing the bearing along? It's hard to see in the video... you will want to indicate from one rail to the other to get them parallel (ish).

Edit: Just realised, looks like you're indicating against the straight edge?

Yes indicating along the front of the top piece of Ali. Checked it with a straight edge, feeler and light first. Will indicate off the second rail once the gantry is together.

The Ali top, bottom and front pieces were CNC machined to size in one go (I sent them out to someone with a bigger table than me....cheating I know but more accurate than making a jig and moving the plate along to machine a bit at a time :whistle:) and clamped together (not the front plate) so I'm hoping that once it's put together it won't need too much tweaking to get them parallel (ish) :whistle:

Did a bit of painting this afternoon for an hour....

Attachment 14664

More machining today, got a couple of new M4 spiral flute taps which make light work of the tapping for the 15mm THK rails on the front plate.

http://tapatalk.imageshack.com/v2/15...58b859208d.jpg

Set the Z axis rails parallel by referencing off the plate side for the master rail then referencing the secondary rail off the master...

http://tapatalk.imageshack.com/v2/15...077f863791.jpg

Flying along now and looking good.

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Originally Posted by EddyCurrent

Flying along now and looking good.

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Cheers...going to order a couple of CSIMO IP-M's and some Nema 34 4&8Nm steppers, 240v N series drivers today for the mill conversion (that's next to do) one's for the X axis on this...

Had to "tweak" some machining on the Z axis stepper mount and also the Z axis back plate...will also have to machine a small pocket out of the Z axis front plate for the ballnut mount as it's not quite (0.6mm) right...

http://tapatalk.imageshack.com/v2/15...f967312c24.jpg

http://tapatalk.imageshack.com/v2/15...8f6c9f19bf.jpg

It's going together quite nicely...so far!

http://tapatalk.imageshack.com/v2/15...5b725633fc.jpg

OK so Z axis is together now, couldn't resist a little test with a cordless drill :toot: The machining on the ballscrew is not 100%, there's a wobble on the drill but it's not too bad and I'll be able to live with it.

https://www.youtube.com/watch?v=wDKn...6hUkKDfklSSdBA

For the eagle eyed among you you'll notice that there are 8 holes for the ballnut holder....erm not much to say apart from oops :stupid:

Does the cordless drill have step/dir inputs to drive directly from Mach3?

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Originally Posted by Neale

Does the cordless drill have step/dir inputs to drive directly from Mach3?

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Good old brain to finger inputs only...

Sometimes the best way! Take those damned computers out of the loop...

I'm a child of the 70's.....so going to use it like an etch a sketch!

The original MPG! Now, there's another idea for a CNC router enhancement...

Just a bit more painting last thing this afternoon is all I managed...

http://tapatalk.imageshack.com/v2/15...88cd207a68.jpg

Did do a bit of research on the electronics today so will post up what I think I need when I've finished researching.

If you don't paint it now you'll never paint it :thumsup:

Quote:

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Originally Posted by EddyCurrent

If you don't paint it now you'll never paint it :thumsup:

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That was my thinking...

Coming along nicely Neil. Can't wait to see this one finished.

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Originally Posted by IanS1

Coming along nicely Neil. Can't wait to see this one finished.

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Cheers Ian, I can't wait either...it's only been about 4 years in the making!!

Quick assemble of the gantry this morning. Got the holes for the X axis ballnut holders to machine later on the Y axis endplates, then some pads to make for the ballscrew ends...

http://tapatalk.imageshack.com/v2/15...f44a98c9c0.jpg

Thinking about it I'll make the pads first and then see if I need to machine back the Y axis end plates...

Made some BK & BF mounting pads....only took a photo of one but you get the gist....

http://tapatalk.imageshack.com/v2/15...8c316465b9.jpg

http://tapatalk.imageshack.com/v2/15...49c4c62c66.jpg

I dont see any means of fine adjustment, unless the holes are oversize ?

The holes are oversize so there's 1mm of adjustment movement. I'll be clamping the blocks whilst adjusting them so the final adjustments needed should be very small....thats the plan anyway!

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Originally Posted by njhussey

The holes are oversize so there's 1mm of adjustment movement. I'll be clamping the blocks whilst adjusting them so the final adjustments needed should be very small....thats the plan anyway!

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You'll probably need shims behind them too, those cut from empty Guinness cans are a great thickness for this :whistle:

I'll have to machine down the pads as they're too deep, wouldn't bet against still having to shim something though.....a great excuse to get some beer in :eagerness:

Well disappointingly I only managed a few diet coke cans at work for shims...clamped one ballscrew to the side and ran the ballnut up and down a few times. The ballscrew has a good wobble to it where it's either bent at the ends or the machining is crap.

http://tapatalk.imageshack.com/v2/15...8eeabfc119.jpg

The drive end ballnut pad needed 1.2mm machining off and the NDE needed 1.2mm of shims...

One of the things that I didn't think through properly with regards to assembly was the X axis ballnut holders. I got the aluminium ones that are small and compact and they fasten from the underside/reverse so on my design I'd gave to take the gantry end plate off to remove them which is far from ideal. I've ordered a couple if MGD16 ballnut holders that can be fastened from the outside. I'll probably have to machine back the base so it is the same height as the current ballnut holders but that's no biggie with the mill.

http://tapatalk.imageshack.com/v2/15...26c26554bd.jpg

Link below is flycutting the DE mount to remove the 1.2mm needed to make it fit.

https://www.youtube.com/watch?v=k7BDi5H78rE&feature=youtu.be

Couple of pics cutting the Ali plate with the bandsaw and then squaring and machining to size the ballnut plates.

http://tapatalk.imageshack.com/v2/15...4beb45cae3.jpg

http://tapatalk.imageshack.com/v2/15...2e2b86288c.jpg

I ordered 2 x CSIMO IP-M controllers and 4 x Nema 34 8.7Nm steppers and 4 x 240V HV stepper drivers today...looking forward to those coming. 3 steppers and drivers and one IP-M are for CNCing the WARCO Major GH mill.

Tomorrow's ordering will be PSU components and belts and pulleys...

Attachment 14751

Got some belts and pulleys today, didn't get them from Belting online or anyone like that as our local company we use for bearings etc. Gloucester bearings (Hayley) were so much cheaper for the pulleys and a bit cheaper for the 2525 belt...

7 off 20 tooth pilot bored pinions - P20-5M-15F £1.73 each

1 off 2525-5M-15mm HTD belt £14.85

2 off 265-5M-15mm HTD belt £4.31

I realise that the pinions aren't pilot bored like the ones from belting online but I was going to have to drill them out to the correct size for the ballscrew ends and stepper shafts on the lathe anyway.

Got another package just now....it's like Christmas :yahoo:

Opened the box from Gary @ Zapp...

Attachment 14753

CSMIO....

Attachment 14755 Attachment 14756

Showing it's size against a Nema23 stepper and AM882

Attachment 14754

Kinco 230V Driver

Attachment 14757Attachment 14758Attachment 14759Attachment 14760

Nema34 8.7Nm motor...(4 off)

Attachment 14762Attachment 14761

Showing the difference between a Nema23 and 34...

Attachment 14765Attachment 14767Attachment 14766

Drilling the pulleys...2x8mm, 4x10mm & 1x12mm

Attachment 14764Attachment 14763

Getting close now Neil !

A cracking set of bits, should run nicely with those fitted.

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Originally Posted by routercnc

Getting close now Neil !

A cracking set of bits, should run nicely with those fitted.

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Cheers!! Only one Nema34 is going on this....it'll be on the X axis driving the twin ballscrews. The other 3 will be going on the mill conversion ill be doing next...hoping to do more tomorrow but work is getting in the way!

That's a smaller nema34 of the bunch, colossal aren't they !

.Me

OK so I'm going to order a new 600 x 600 x 300 cabinet and parts for my electrical panel, can someone check to see if I need anything else...if I've missed something:

600 x 600 x 300 - 1 off
20A door isolator (presume NC contacts so contact is broken when door's opened?) - 1 off
Emergency stop panel mount button with NC contacts - 1 off
Green push button panel mount, NO contacts - 1 off
Red push button panel mount, NC contacts - 1 off
Green LED panel mount light - 1 off
Top hat slotted DIN rail - 2m length
2.5mm grey DIN terminals (gettting 50 off)
2.5mm Earth terminals (getting 25)
bootlace ferrules 0.75mm, 1mm, 1.5mm (100 of each)
Crimping tool - 1 off
25x40 slotted cable trunking - 2m

I've got 2 x 120mm 24V cooling fans which I'll get filters for which I'll mount on the sides
I've got 1.5mm^2 4 core shielded cable (about 25m) for connecting the steppers to the drivers
Was thinking of getting 3 core 0.75mm^2 shielded for the limit switches, is this the correct cable to get?
What other cable will I need?

I'll be ordering parts for my PSU, so far looking atthe below components. Can someone please comment on them please to make sure I'm going in the right direction?

Calcs:
Toroidal voltage V(DC)=1.4xV(AC), so 70/1.4=50V
Question, I've read that if yout supply is greater than 230V then the voltage output is higher which would be a bit too near the max 80V the AM882's can take if there's back EMF from the steppers on deceleration? So would it be better to get a 2x24V transformer as linked below?

Current: I've 3x4.2A steppers (Z axis, Y axis and a future 4th axix) plus a 6A Nema34 making 18.6A but 60% is 11.16 so call it 12A? So transformer needs to be 12Ax50V=600VA sdo nearest is 625VA.

Capacitors: C(uF)= 100000xCurrent/Voltage = 17,143 so a 22,000uF 100V capacitor should do....any ideas where to get an economical one or are multiple smaller ones better?

Bleed resistor, I'm either going to use one switched through a relay or is it not worth bothering with? I'm more inclined to use one as I'd rather discharge safely than just leave the steppers to drain the caps. My calcs are: R=5000000/2200=227Ohm, rated at V^2/(2xR)=10.8 Watts. Any suggestions on what to get here?



Toroidal Transformer - http://www.airlinktransformers.com/c...nge/CM0625224/

Rectifier - http://www.rapidonline.com/electroni...-mb352-47-3226

I'm sure there's more that I've forgotten but I'm sure that someone will suggest it (hope so...)

The advice I was given was to get a 2x24V transformer and having measured the output and input voltage I'd definitely say that's the best advice. The power to my house at least tends to be a few volts over 230V so a 2x25V transformer + back EMF would probably push it over the magic 80V.

I went for a 1000VA transformer in case I ever added a fifth axis, to be honest though I reckon I could probably add a 9th axis it's so over kill. At 625VA you should be fine with just three steppers, you may or may not need to put together an inrush limiter, you'll probably get away with a Type C or D breaker though - a type D breaker would stay in occasionally for me.

For capacitors I used 4 of these: http://www.ebay.co.uk/itm/1-NEW-NIPP...-/280934713637 Multiple small caps were a lot cheaper than one big one.

I have a bleed resistor which will bleed the capacitors in a few minutes if steppers aren't attached, if steppers are attached they bleed in seconds. I forget what rating it is but it's a lot less than 10.8W, 0.5W rings a bell. I know the recommendation is to bleed the caps in so many seconds but it was a play off between safety and heat produced in the case. To improve safety I fitted a UV style meter to the front of the case to tell me cap voltage and fitted a cover over the capacitors, total cost about £5.

I think you'll want more bootlace ferrules than that and I used a mile of single core cable (can't remember if it was 0.75mm or 1.0). You can get jumper bars for the DIN terminals to make them one large block which came in handy.

Neil Have I missed the rectifier? The cable for the limit switches can be as small as you like as there is practically no current to speak of.
I have used 25 -25 with no problem and my personal opinion is that the bleed resistor is not needed. ..Clve

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Originally Posted by Clive S

Neil Have I missed the rectifier? The cable for the limit switches can be as small as you like as there is practically no current to speak of.
I have used 25 -25 with no problem and my personal opinion is that the bleed resistor is not needed. ..Clve

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Yes you've missed it.....I'm going for a 35A 200V one from Rapidonline....:thumsup:

I'll get some 0.75 tri core shielded cable then for the limit switches.

I think I'll measure the supply voltage here and see what it is out of interest.

Done some machining today. Also had the rest of my order from Gary @ Zapp this morning.

http://tapatalk.imageshack.com/v2/15...3ec6bfd29f.jpg

Machined the Y axis ballnut bracket that connects the Z axis to the Y axis ballscrew...

http://tapatalk.imageshack.com/v2/15...dc19043f7b.jpghttp://tapatalk.imageshack.com/v2/15...8914af820c.jpghttp://tapatalk.imageshack.com/v2/15...7c7c45fa42.jpg

Seeing as I've got my MGD16 ballnut housings for the X axis I machined the right gantry side.

http://tapatalk.imageshack.com/v2/15...75c78ad9ea.jpghttp://tapatalk.imageshack.com/v2/15...b9dcac733a.jpg

More machining tomorrow [emoji2]

Both ballscrews are fixed to the frame now. Machined the second gantry side for the ballnut holder. I bought some bigger pulleys for the X axis (40 tooth ones instead of 20 tooth ones) as the standard belt I've got is 2525mm and there's a lot of spare belt with the 20 tooth ones. I'm using an 8.7Nm Nema 34 run with a 240V drive so I'm hoping the extra inertia from the pulleys shouldn't cause too much of a problem?

http://tapatalk.imageshack.com/v2/15...2604a5575e.jpg

http://tapatalk.imageshack.com/v2/15...1b77cd29a6.jpg

http://tapatalk.imageshack.com/v2/15...978f37d42e.jpg

http://tapatalk.imageshack.com/v2/15...a373844a5d.jpg

I've bought the transformer, rectifier, 4 4700uf caps and holders, a 600x600x300 cabinet, loads or bootlace ferrules, wire, din rail and terminals, door interlock....tonnes of stuff but I'm sure not everything i need.

I'll be picking people's brains about the safety relay/s for the safety features...

Did a bit of machining today. Machined 2 x countersunk holes to suit M8 bolts on the Z axis back plate to take the Y axis ballnut bracket.

http://tapatalk.imageshack.com/v2/15...7075b2bae5.jpg

http://tapatalk.imageshack.com/v2/15...c6ed43424a.jpg

The Y axis ballscrew will fix straight onto the back of the gantry so won't need shimming.

http://tapatalk.imageshack.com/v2/15...52d787c6ca.jpg

http://tapatalk.imageshack.com/v2/15...237d9e333b.jpg

Scratched my head a bit today trying to work out how to mount the Y axis stepper motor so I can adjust it to tension the belt. In the end I've decided to put the pulley on the rear of the stepper and mount the stepper on the front via a bracket...

http://tapatalk.imageshack.com/v2/15...4e0ce78ea0.jpg

http://tapatalk.imageshack.com/v2/15...a74cd0fe07.jpg

I'm hoping that as the only tension on the stepper is from the belt that this arrangement will do?

Nice build sir!

I don't have first hand experience mounting stepper motors this way but it looks trouble. Maybe too much strain on motor?
I guess as long as you fabricated the mount you might as well run it and find out.

Do you have special machining on ballscrew? I notice longer area for the pulley? Or is it just my eyes...

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Originally Posted by njhussey

Scratched my head a bit today trying to work out how to mount the Y axis stepper motor so I can adjust it to tension the belt. In the end I've decided to put the pulley on the rear of the stepper and mount the stepper on the front via a bracket...

I'm hoping that as the only tension on the stepper is from the belt that this arrangement will do?

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Bad idea that dude.!! Bearings will suffer and could cause resonance which will affect motor. Just pocket the Mount deeper so pulley goes thru it.
Or have idler arm tensioner tension belt from side of gantry.