[yolk]

yes JD, i used it a lot on my smaller cnc. haven't tried wax yet, but will soon test it to do some lost wax castings.

[JDHill]

Cool -- thought I'd mention it, just in case.

[yolk]

tips are always welcomed. do you cnc machine stuff?

[JDHill]

Not so much in the last several years, but yeah, since around '91. Mostly 2.5D stuff though -- I come to it via the cabinetry business. The pics in the last post are were from playing around with Rhino/VisualMill, from probably around 2004, cut on this machine.

[yolk]

lovely machine. you really are a jack of all trades!

[JDHill]

It's fun, but frustrating to try to cut anything but wood -- it's not realistic to use anything but air for cooling. Some day I would like to have something similar to your machine.

[yolk]

first bigger part i just made - still lots to learn as i am used to cut plastics and renshape.

[yolk]

the part is for the high speed spindle - just mounted it.

leo, how is your machine going?

[JDHill]

Nice -- looks like you're going to be having some fun in the near future. The spindle is ER25? -- what speed?

[yolk]

i love working on the machine - it's not really big but suits my purpose of doing prototypes and small series in metal.
i had a small gantry router with a dinky stepper controller and it was a pain to work with.

yes this elte spindle has a ER25 collet. it goes up to 24'000 rpm, but i guess i'll run it mostly at 12k.
it's just for the small cutters, 1-8mm. for the bigger ones (the pic shows a 20mm finishing cutter) i use the big head - it has much more torque, but has a max speed of 3000 rpm. working with a sk40 taper is also nice, because once i measure the tool lengths with the touch probe and save them i don't have to reference Z anymore.

[JDHill]

Never had occasion to use these myself, but perhaps they could make sense for setting up a few often-used tools: http://www.genswiss.com/qcollets.htm (@ 0.001" TIR, though, maybe not). I was checking out that Centroid control a bit and it looks to be robust enough to easily justify the high speed spindle. We also have an older machine that's out of commission due to its prehistoric control; now you've got me thinking that maybe it needs to be resurrected.

[yolk]

thank you for the tip.
centroid usually sells turnkey solutions, all pre-cabled. if you want to buy the separate parts you can do so at www.ajaxcnc.com. support is sometimes tough to get in touch with at ajax - but the centroid controller is lovely.

this video makes me chuckle every time - very thick southern accent, lovely retrofits:
http://www.youtube.com/watch?v=sGyfqrDtY4E

[JDHill]

Thanks for the link, it looks like this might not be too bad of a job, compared to what it would've been five or six years ago. The machine is pretty much identical to this one. It's not slow, it will move around 50m/min, but the control is terrible: proprietary, 300-line maximum, 3.5" 720K-only floppy disk, and the RS232 never ever worked.

[yolk]

very nice machine. depending on what servos your machine uses you can keep them and just exchange the encoders - the centroid uses a 8000 counts per revolution. old servos have encoders with much less resolution.
they come in 1/4", 3/8", and 1/2" hollow shaft sizes.
i wouldn't go with steppers like shown in that video.
also - the unlimited file size is sold separately at ajax - i bundled it together with some other additional features and got a good price. although the 4mb file size it usually comes with is already quite large. most 2.5D stuff is a few KB in size.

[JDHill]

I think that's about the size of it; the stock DC servos should be fine, but the encoders were always a problem; we'd often have cases where the machine would run part way through a program, only to stop with an 'impossible arc' error. Since the control couldn't predict this, we always assumed it was due to insufficient encoder resolution. We just dealt with it though...re-program and re-program until finally you'd get it to work.

[edit: to be accurate, I recall now that it was an INpossible arc error. Me make an inpossible arc? That's unpossible! ]