Warco Major CNC build log

**BillTodd** · 21-10-2009

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** · 24-10-2009

Originally Posted by BillTodd

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** · 25-10-2009

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** · 08-11-2009

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** · 17-11-2009

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:

**Robin Hewitt** · 08-12-2009

I do like making things difficult for myself, but when it comes to the firmware I become a control freak. If it doesn't do what I want it to do then I want to reprogram it down the USB rather than fudge it. Nothing quite so reassuring as having all the source code :whistling:

Stepper drivers, phase controller and pendant connect with RJ45 patch cords to keep everything neat and tidy, lots of buttons and well buffered I/O for everything I could think of.

The limit switch and tool touch inputs are designed so I can short them to ground via an LED and get a visual check at the far end of the wire. Three FET's to drive the suds pump, quill lock and something I haven't thought of yet. A socket for one of Gary's jog encoder do-berries, a main motor kill switch to keep me safe while setting up, fuses on board and an input to tell me if 12V goes away. If the 5 volt fuse goes then it's goodnight Vienna so no way to monitor that.

**Robin Hewitt** · 22-12-2009

There's my Christmas entertainment arrived in the nick of time, not bad for 35 Euro's

I've only found one blooper so far, a 6 pin opto isolator with the wrong pinout. Luckily RS had a 4 pin part that fixed it

Think I'll put everything down before I mount the processor, that way I can check it's connections, make sure I'm not overloading it anywhere.

The three little boards on the right convert Kinco stepper drivers to RJ45 with all the wiring neatly out of sight, should look great if I got the measurements right :whistling: