So I’ve been offered this mill for free. Here are the main issues:
The motors appear to have 4 poles (Same pinout as 4 pole motors I’ve played with) instead of 2, which I think makes drivers pricier. However I could potentially DIY drive them with FETs, since that isn’t actually too hard with 4 poles.
The main control board aka the giant rack of hand assembled electronics is basically junk. It’s a huge rat’s nest and only achieves very basic parallel port control, and keypad control. So I’ll probably be replacing that with a nicer, modern interface friendly board.
I have NO IDEA what those stepper motors are. No nameplates, not even anything about required voltage. I can figure that out though.
It’s really heavy and would likely cost me a good $200 to move.
That said, it’s absurdly strong, free, and comes with a toolchanger which is pretty cool.
How would you go about utilizing this thing? I’m going to try and find a specific model number later tonight.
Originally shared by Nick Parker
Its a project for sure. I’m betting it is servo controlled instead of stepper. The ‘things’ are diodes. The smaller transformer converts 220 to 110 for the controls. If you do pick it up make sure your house can handle the power… looks like 220 at 20 amps.
If its free, you may want to pick it up, turn around and sell it if you can’t convert it.
It actually uses massive 4 pole stepper motors. I’m trying to figure out how to drive them cheaply right now.
Update: I found some old drawings of the interconnects between the various boards and there are differential step/dir pins pictured. I’m currently calling and emailing various old manufacturers trying to find out which of the 16 pins connecting each driver to the logic boards are step/dir.
As soon as I find them I should be able to interface the whole mill with a modern controller.
some fun stats:
The motors are 400 steps/rev, weigh 18 lbs each and take 8A/phase max. They run happily at roughly 4A/phase and the drivers appear to do 1/8 microstepping.
Assuming the ball screws are the same as the similar mill that (i believe) only differs in the gearing between screw and motor, it has .0127 mm resolution right now.
The current challenges are finding these damned step/dir pins (oh woe is me, I can’t find my damn oscilloscope) and getting the couple thousand pound machine to my house.
Update: a summary of the connections to the 16 pin cable from logic to the driver board.:
1:to timer pin and several capacitors jumping to gnd. May be logic level v+
2: to middle pins of 2 optos
3:to middle pins of 2 other optos
4-6:unwired
7:through 2 resistors to an opto’s side pin.
8:to opto middle pin (same opto as 7)
9:gnd
10/11: fwd/rev lim
12:no connects
13:connect to 15 via resistor
14:connect to 16 via resistor
Update again since this post got back on my notifs: The old controller 100% works. I can input up to 1024 lines of gcode into it and run programs. I just need to get my 3 phase spindle set up and i can start making chips. The PC that’s going to become my linuxCNC box is having some BIOS issues, but if it fails me i can get a workable replacement for $100.
Oh also the mill’s been moved to my garage.
