Thoughts and feedback as I progress pls

[luke peter]

I have said it before, but I will say it again, you are building a really aesthetic machine... Not too far from making chips now.

[Mogal]

Hi Luke, just went through your build. Very impressive!

You got me thinking about my steppers and drivers at 36v.
I was happy/content with the old machine, but this is a new game here.
The steppers I have, have a very high inductance of 6.8hm and was speed limited at about 120ipm. (1/2" double start, 0.2 lead, leadscrew)

I think it is time to upgrade after all. So I've compiled this:

Dual Shaft Nema 23 Bipolar 3Nm (425oz.in) 4.2A 57x57x114mm 4 Wires
Digital Stepper Driver 2.4-7.2A 18-80VAC or 36-110VDC for Nema 34 Motor
60VDC/10A Switching CNC Power Supply (110VAC/220VAC), KL-600-60

- Only thing is that this driver says its for nema 34? (I'm sticking to nema 23s)
- Would the 60v 10a PSU be enough to power these drivers/steppers?
- Most info seems to point at 50v tops for nema 23s?

Just spotted this: 4 Axis CNC Router Kit 3.0Nm(425oz.in) Nema 23 Stepper Motor & Driver DM556T

[Mogal]

I couldn't edit my last post, but these steppers instead (as I hope to not need inertial dampeners on the new machine - and a bit cheaper)

Nema 23 Bipolar 3Nm (425oz.in) 4.2A 57x57x114mm 4 Wires Stepper Motor CNC

Aliexpress 60v 1200 watt switching PSU
- Got the impression that the 600 watt would be enough to power these steppers?

[luke peter]

If you havn't had a read through those articles, do so - They pretty much walk you through power supply sizing, and max drive voltage for steppers etc.

https://www.geckodrive.com/support/s...ly-basics.html
https://www.geckodrive.com/support/s...or-basics.html

I have bought pretty much identical drivers to the ones you linked, and identical motors. I bought 2 x 800w 65v switching supplies (12A) power supplies, which will be more than adequate (steppers draw less than their rated current when driven like we intend to drive them)

1 x 600w will probably not be enough for your motors, it will be on the red line if not slightly over.

Drives will be fine for nema 23 motors.

The 556 drivers in the kit are rated for 50v max, so you would want to run them a little lower than that, 45-48v most likely. If oyu have super low inductance motors, it would be fine, but the 3.8mH really want around 67v.... at least as far as I understand it based on the maths in Geckos article.

[luke peter]

I bought my stuff off taobao, which is like the aliexpress, but for chinese nationals, so its usually much cheaper (only issue is you have to communicate with them in chinese, and use a freight forwarder).

Its worth looking into for spindles and drives etc, I paid less than half of what I would if I had purchased exactly the same stuff in South Africa.

[Mogal]

Well, I have the Z axis moving now
I have yet to make the mounting bracket for the Z stepper.
I have yet to figure out sensor placements.
I got some M18 Inductive Proximity Sensors that I'm going to use, but if I can find some smaller ones,
I'd like to see if I can sandwich them between the two Z plates.
My Z axis is now 1605 leadscrew.
On the backside of the gantry, I will be mounting a 1/4" 1.5x3 steel angle to reinforce and lock in the gantry.

I'm waiting on the new steppers, drivers, power supply and the belt for the Z axis.

[luke peter]

Looks awesome!

The angle is a good idea, closing the edges of the t slot will help a lot with torsional rigidity.

I bought m8 inductive proxies for my build, also not sure how I am going to mount the z ones...

[Mogal]

Well, as it stands now, the machine is mechanically complete! But I have still yet to place sensors.
I have torn down the machine and started to reassemble it while calibrating along the way...
Double checking all the nuts/bolts, squareness and alignments as I go...
I have added some extra cross bracing on the bed of the machine with some 4040 (I had the materials on hand so...)
I also decided to weigh the Z axis... I'll say the axis is roughly 30 lbs and adding the dry 2.2kw spindle ups that to 40ish lbs...

My drivers/steppers and PSU have all come in, so I'll be starting on reconfiguring the control box soon after.

And a silly question, does the sensor orientation make a difference to the accuracy?
- Can it slide into place, or does it need to be face on? (or would they trigger accurately either way?)

[Mogal]

Here are some shots of the Z axis and spindle.

I never dreamed I could raise the spindle with one finger like this!
Very happy with that.
I have some constant rate springs I was going to install, but is it necessary with it being so easy?

You can see the back brace installed in the one pic.
That really did make a difference locking to two pieces together and keep them aligned.

[peteeng]

Ho Mogal - No springs are not required. Especially with your step down [pulley. Z will lift 100's of kg with this arrangement. 3Nm at 10mm pitch will lift 173kg then is it 2:1 or 3:1 over that? so at 500rpm it will lift 80kg without the pulleys.....
very strong Z axis...Peter

I see you have changed to 5mm so at 3Nm the leadscrew itself will lift 2x173! then you have the pulley reduction. Move a small car....

[Mogal]

Well, NONE of this was ever in the plans. I always thought I'd do the bucket trick...

That is until I was introduced to a friend's CNC that he modded for an on board travelling cooling system.
He used the common computer water cooling system.

So during my adventures, I came across this reservoir/pump/readout all in one.
Added a 120mm rad and fan and come up with this idea (pulling air through the rad)

I love the compactness/simplicity of it all, Hope it cools sufficiently and doesn't plug up with dust too quickly.

Still working on the Z limit switches. Unfortunately I had to resort to mechanical switches as I couldn't safely (or easily) mount the inductors.
They would stick out too far/to large and could get hit/bumped.

Some pics:

[Mogal]

Well after an amazing summer, I'm back in the shop!
Finally got the power to the machine! It moves!!
Had a couple glitches with the wiring. One of the cannon plugs developed a short INSIDE the connector.
First power up and everything went POOF!!
Thank goodness these stepper drivers have built in protections.
So after that was sorted out, I had a few more issues. One of the jumper plugs/pins had failed on the BOB and didn't connect the pins.
Took a couple hours to figure that one out and fix it.
But then, TADA! It all powered up!!

To do list:
- Go around machine and ensure every nut/bolt is tight, tidy up as I move around the machine
- Making sure everything is aliened as possible (for the first run through)
- Build a guard for the X leadscrew on the far side (to match the one in view)
- Cable management (Get the drag chain all setup and loaded - Might need a bigger chain)
- Ensure all my grounding wires are correct and sufficient
- Calibrate Steps/inch and to square up all axis
- Finish wiring the spindle, setup the water cooling system
- Test run the spindle
- Tram the spindle
- Calibrate the limit switches and set X axis limit switches for squareness
- And a couple other things too I guess

I have one (major?) hiccup ahead of me, and not sure how I can deal with it yet.
The (brand new) 2.2kw spindle has about 0.006" linear play in the axis <-- Will that clear out with the run-in process?
- If it does, all good then!
If it doesn't, what are my options? I have pin wrench, but I'd have to modify it to make it fit.
But I don't have a press or means to move/remove/adjust bearings.

If it turns out I need to buy a new spindle, I'll be going air cooling (Any 2.2kw spindles that have a separate fan not attached to the spindle?)

Either way, exciting times seeing this DIY monster comes to life!!

[Mogal]

Well, I don't have all the tools needed to rebuild this 'new' spindle (yet!)
So looks like I'm off to find another one... sigh...
If you increase the video quality, you can clearly see the spindle sliding up and down causing vibration during the run time.

Looking at the G-Penny 2.2kw 220v w/ceramic bearings
https://www.aliexpress.com/item/1005...8dak567xh&mp=1

[Mogal]

Well a buddy helped with pulling the old spindle apart.
Turns out it's a 3 bearing model. And I believe it was a used/returned spindle.

I'm not 100% certain what caused the axial play, but after a cleanup and
reinstall of the bearings, everything tightened up and no spindle play
is noticeable now. But it still sounds terrible. Not sure if I got enough preload

Really impressed with the new spindle now. Seems way better in every way.
It's even properly grounded, with a good size ground wire.
Spun it by hand, and it's clearly night and day over the old spindle.
Hopefully put power to it soon.

The new spindle is longer and now posses some issues with the drag chain
setup I was going with, so a redesign is now in the works for that.

Hard to believe that both these spindles have the same 2.2kw rating,
the smaller one rated at 8amps, the larger one, 10amps.

I ordered a UB1 to go with the UC300ETH as I need a couple more in/out puts
and the 3 relays are a bonus as well as the full spindle control.
Ordered a larger set of drag chains too.

As a side note, yesterday was our first snow fall of the year.
Got about 1.5 inches, and it's mostly gone today.

[Mogal]

Well, I'm almost there.
I still have to wire up the stop switch and the probe.
- But my big stopper is coolant. Should be here in a couple days.
I'm going to rework the VFD wiring. As of now, I'm using two 18/4 cables
but only need 5 wires. So I found some cheap shielded 5 strand wire and
canon plugs to match that I'll change out when they get here.

Then the commissioning starts.

I don't really like my coiled wires, but not really sure what else I could do?

I also came across this post that discusses the cooling requirements of these 2.2kw spindles.
So curious as to what'll happen with this setup.

https://www.cnczone.com/forums/diy-c...lculation.html

[Mogal]

OKAY!!
I'm up and running!! Woot woot!!

But things are not all doubt woot atm lol.

Seems I have VFD issues as the spindle fluctuates speed.

Spindle Specs: 2.2kw, 400Hz, 10A

The VFD outputs 9.98v

If I set the spindle to 12,000rpm, the return control voltage is 5.82v
Giving roughly 16,000rpm, but it fluctuates between 16-18,000rpm.

Any way to correct that? From everything I've found, seems it's the VFD itself?

[Mogal]

Okay, I'm 99% done!
I trammed the router to 0.004" over 12"
- Thinking about making some tram adjusters to make it a little easier (and a little closer)

It was warm in the shop today. I wasn't running the spindle too hard, (2" surfacing bit) but
the temp increase was only 5 degrees warmer then ambient. Once the
spindle stopped, the temps dropped pretty quickly. So preliminary tests
on the cooling system are good.
With the next to zero load 30degree bit, the spindle bounced between 1-2 above ambient
while cutting the lines and doing the text.

So only things left do do is finishing installing the rest of the inserts (Had to order more)
And I'll be replacing the blue tool setter for the silver and black one when it gets here.

I think I'm going to change out the Z axis pulley to be a one to one ratio.
The stepper is spinning a little too fast I think.
It's set to 100in/min. with a 2:1 pulley and a 1605 ball screw.

I know weird grid spacing, but 2" was too many and my old machine had 4" spacing and was not enough...
so 3 it was lol.

And a follow up to the spindle.
I'm going to be re-wiring the spindle and cleaning up the ground wires to see if EMI is causing the issues.
For now, I have the spindle auto on/off and manual speed control at the spindle. No big deal, but would be
nice to have that full speed control... one day!

Cheers all! And thanks a bunch for following me through with this.
I had alot of fun building it and glad I went the DIY route!

[peteeng]

Hi Mogal - That last 1% takes 20% of the time!! Enjoy - Peter

[Mogal]

I got bored and made a video...

[peteeng]

Hi Mogal- Thats fantastic! re: thread grid. My latest client build made his grid staggered (diamond?) vs a square grid and it seems to give more options. Just a thought for your next build. Have fun Peter