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Author Topic: Finally Ready to CNC  (Read 2176 times)

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Finally Ready to CNC
« on: September 04, 2007, 02:12:47 AM »
Yes I am now ready to start to retro fit CNC as I have purchased and received my ZAY45 Mill ( Just like the Grizzley ones on www.industrialhobbies.com) those $$$ were suckers to save and whillst doing that you would get time to keep selecting bigger mills ! Suprised that my account and password was still active as it was 12 months ago since my initial enquiry to purchase one :o I guess the itch to CNC a mill still exists !
Has any one got plans or closer pics/ advice on how they converted one of these grizzleys mills to CNC.? and what size/type stepper ect ,,they successfully used.ect ect !!
I have made a choise to use the PMDX 131 breakout board with G202 drivers ( Mill was ordered and fitted with a 3 phase motor with a VFD controller so that allows me to look into fitting the PMDX 106 spindel controller) Well those are the plans. Any help to do it the right way the first time would be very much appreciated.

Andrew

Offline jimpinder

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Re: Finally Ready to CNC
« Reply #1 on: September 04, 2007, 08:36:42 AM »
I take it the Mill is as per the pictures, but is just manual at the moment. The write up tells you basically what they have done. It does not give you, however, any specs for the finished mill, such at table speeds etc, so just what the performance is, I wouldn't know.

If you are looking to convert your mill into a CNC machine for as little as possible, I would personally use stepper motors instead of servos. The driver boards can be connected directly to your breakout board (or even directly to your computer port) and give excellent performance. You do not need to bother about feedback.

I am in UK so cannot give you any idea where to buy you motors - but mine ( for a similar sized machine 5" lathe with a large milling head) are 220 Ncm. They have a 12mm through shaft. I have mine connected to the lathe with toothed belts, giving a 3 to 1 reduction as per the photograph. This was the simplest way I could devise to fit them on.

Looking at the photos of your mill, the firm seem to have done something similar with their servos.

The motors are driven by Stepmaster drives. These are American, I got them on Ebay. They cost about £30 each ($60) but I imagine you can get them cheaper over there. They are rated at 2.5amps, fully adjustable and come complete with a comprehensive wiring diagram.
I run them using 24 volts from two leisure batteries that I happened to have

I did not bother with a breakout board. The Stepmasters are run direct from the printer port - (three wires per drive - step, direction and common). I built a small driver board to trip two relays from the printer port to control the spindle and I have control of M3, M4 and M5. Speed I have to control manually from the Omron inverter (which I was given by my brother-in-law) I am working on speed control using a servo run by the pwm output from Mach3.

The relay board I am going to rebuild using a single ic Darlington array to drive 4 relays - two for the motor, but also two for coolant control.

I still have all the input wires to go at and I will probably try to fit some sort of reference device, so that the lathe/mill can reference itself if need be. I do not see the need for Estop limits - you can set the soft limits on Mach3.

The whole thing has cost me £200 ($400) so far, and I am very satisfied. I have turned handrail stanchions on the lath, and cut window spaces (with rounded corners) using the milling head (these are 4 inches by 3 inches) and both these are jobs that I simply could not do manually, without a lot of additional tools.

Not quite the $199 or whatever Art says, but very, very cost effective and satisfying.
Not me driving the engine - I'm better looking.