Hello all:
The short version: My lab has an old Minitech Mini-Mill 2 from 1993 (?) that is in an almost pristine condition except for a heavy layer of dust. The story goes that it never received much use because the steppers on it were just too weak to make it do more than carve words into wood and plastic.
A couple weeks ago I started to under take the task of reviving the mill. All documentation has been lost, as well as all tooling. The only thing we had was the mill itself. I got the trial version of Mach3, and a brand new computer, and went to work. The early version of my trials can be found in the Mach3 forum under the thread: "Need Help!- Mach3 with old (1993) Minitech Mini-Mill/2"
We succeed in getting around the low current issue with modern parallel ports by abandoning Mach3, and trying out EMC and setting it for 50us pulses. I think we will stick with EMC2 because I really like its HAL abilities. The Hardware Abstraction Layer and the software programmable logic controller should allow me to do some fancy stuff in software like programming the drivers to only allow jogging away form triggered limit switches. Plus EMC is open source, and I like to save money (even if its not my money)
Anyway I decided to start this thread because the rest of the project will have nothing to do with Mach3. I plan an asking advice about new steppers and drivers and a general upgrade of the electronics for the mill. And I will also document the progress.
Things accomplished so far:
1) The mill has been disassembled, cleaned, lubricated, and reassembled. After some research I decided that any kind of generic lithium grease was good for the lead screws, and we used way oil (Lubiplate No 3.) on the rails.
2) Decided that the current servos are too puny. They are a 16+ year old design (round) and the specs follow:
Superior Electric "SLO-SYN" Type: MO63-LS-502
rated for 4.6Amps, (2.25v - not sure what the voltage rating means on steppers...) and only 150 oz-in of holding torque.
3) Began searching for a new set of drivers, a descent breakout board so I can add an E-stop and limit switches, and stronger steppers. In the next post I will describe my proposed shopping list and ask people if they foresee any problems or incompatibilities.
Thanks everyone for following my thread