Warco Major CNC build log

[BillTodd]

Stuck waiting for bits

Did add an air driven spindle lock, now working on the suds nozzles.

Is that a spindle lock or a Z axis lock?

Have you a picture of the whole 'honking plate' z axis? (looks good :))

[Robin Hewitt]

Is that a spindle lock or a Z axis lock?

Have you a picture of the whole 'honking plate' z axis? (looks good :))

By Jingo you're right, I used the wrong word :heehee:

You want a picture from a different angle?

Have to fix a front gate this afternoon. Strict instructions, on pain of nagging :naughty:

[BillTodd]

You want a picture from a different angle?

Just a wider angle showing the whole of the axis would be good :)

[Robin Hewitt]

Testing out my new quill lock then the quill jammed

Two hours finding the problem. Thought I'd got cast iron dust in the guide when I drilled the holes for the pneumatics. Hadn't. Though the clamp was binding. Wasn't. Thought I'd deformed the quill with excessive locking force. Didn't. Thought it had to be gunge, fetched the quill out and got it clean enough to eat off. Did no good.

If your Warco quill seizes up for no apparent reason and defies all efforts to free it I have the solution. 2 minute job, miracle cure, no disassembly required, will cost you a bottle of Hobgoblin posted to Sussex :naughty:
Quill now tracks up and down easy peasy, the Z depth on the computer screen agrees with the linear scale on the mill +-0.01mm moving in either direction. However, cutting forces can put them up to .05mm out. Hence pneumatic quill lock.

Yes, I know 0.05 is only 2 thou

[Robin Hewitt]

Just a wider angle showing the whole of the axis would be good :)

Here 'tis, and here's a link to the 1.7Mb original image http://www.robinhewitt.net/big.jpg

I left the Z screw detached from the honking plate, it bolts on from below sort of thing
Next I have to fix the ball screws, I didn't look after them and 10u backlash has become 75u, at least I think it's the screws. Have decided to spring the nuts and go for true zero backlash :naughty:

Assuming 1Nm on the screw is enough to move the table under all circumstances, that's 1256N force on the nuts, call it 280 lbf because I don't think in Newtons :heehee:

I have the design, appropriate Belleville washers have been purchased, waiting for the oil pipe fittings, blooming postal strikes, grumble moan complain.

[BillTodd]

You've made a nice job of that Robin :)

Assuming 1Nm on the screw is enough to move the table under all circumstances, that's 1256N force on the nuts, call it 280 lbf because I don't think in Newtons

I pre-loaded my roller nuts to about 400N per roller. There isn't any actual axial load on my lead screw; the pre load stops the roller moving axially within the nut. That seems OK for manual milling with my machine.


It's actually hard to tell exactly what pre-load you've set with a belleville you have to guess using a displacement and trust the manufacturer's table for the spring.

[Robin Hewitt]

It's actually hard to tell exactly what pre-load you've set with a belleville you have to guess using a displacement and trust the manufacturer's table for the spring.

I know, but whaddya do? :whistling:

The extended ball nut housings are now cut, see pic. I plan to rip it all apart tomorrow and try for zero backlash by preloading the nuts

Ran the fast milling collet today at a tentative 4150rpm and looking good. I'm driving it with 44:13 pulleys off the main spindle.

[Robin Hewitt]

ZERO BACKLASH ON X AND Y

Well, none that I can feel anyway :heehee:

First pic, horrible things done to Gary's ballnuts :naughty:

Pic 2, Belleville washers just about to get bolted onto nuts.

Pic 3, My extra speed ER11 collet chuck thingy

[Robin Hewitt]

Added a set of Gary's 240 VAC driven stepper drivers and a splash guard.

Don't know how fast they go yet because my computer can't crank them up past top whack and refresh the screen at the same time.

I suddenly feel a need for belt guards on the steppers.

[ame="http://www.youtube.com/watch?v=bAoUW5bszRA&layer_token=c1adb91cff5d14e3"]YouTube- Noise[/ame]

Would you describe this as "quiet"? :heehee:

[Robin Hewitt]

I added the belt covers on the X, Y and Z motors.

The factory fitted screws holding the z axis motor together stopped 3mm short of the base. Not much but enough to hold a flexi conduit fixing so I could tidy the wiring up.

If I'm doing pretties I must be nearly there. The ultimate aim is to cut injection tooling, so thought I'd try the fast spindle and instantly found I needed yet another belt cover :heehee:

I cut a 3mm slot 0.5mm deep across a piece of aluminium at 6100rpm. A fairly good mirror finish resulted except the centre of the cut where the tool proved a mere approximation to centre cutting

Extreme close up of the cut below. I measured the width at 3.00 to 3.01mm so runout is around 5um, not bad considering the ER11 collet was only finger tight.

Next the electronics...

I currrently run DOS because it leaves the PC timer interrupt free which is nice. OTOH, new computers do better graphics, are much faster and prettier, even if serial and paralel ports have now both been consigned to the dustbin of history.

Obviously I need a processor on t' mill end of the wire. I am opting for a Freescale 8 bit micro running C. It comes in a dinky little 48MHz, 64 pin, square package with buckets of I/O pins, 32k of flash, 2k of RAM, timers, serial port for the phase converter and a full speed USB 2 connection for the PC link. (Real reason for this choice is that our tech bod is looking at it for another product so we already have all the dev kit, programmer and free samples) :naughty: