Messages

1

General Mach Discussion / Re: pulley ratio ,feedrate and motor tuning

« on: April 07, 2015, 03:00:09 AM »

Thanks for the sanity check. I'll work with the 1/8 setting to see what kind of results I can get. As of today, I was able to get all three axis dialed in and at least drawing (pen instead of cutting head) in units that match my design. However, I noticed that when it encounters curves, like a radius, the X-axis goes limp and skips steps like crazy while the Y axis is fine even though they are setuo identically so the curve looks more like a straight line! When I increase the voltage at the controller for the X axis, the thing hums (even at rest) and runs hotter than the former setting, but it does complete the arcs as expected. The motors are rated at 1.7A 12VDC and the controller has a setting of 50% of max 3A which would mean I'm only running these things at 1.5A. Should they be making that kind of noise and running that hot? THX

2

General Mach Discussion / Re: pulley ratio ,feedrate and motor tuning

« on: April 06, 2015, 09:17:42 PM »

I've been following this discussion as a newbie to CNC and have experienced everything in this thread. As I try to dial in the ideal mix of speed and torque, I find myself vacillating between different micro-step ratings on my controller to drive my NEMA 17 steppers (its a home-built micro-mill) with varying results. So I have to ask, is it always better to drive the steppers at the highest micro-stepping setting to maximize torque?

For example, I can set the microstepping to 1/8 or 1/16 giving me 1600 steps per rev or 3200 steps per rev respectively. But I also am trying to minimize the stepping voltage setting so I don't burn up the motors. At 25% voltage, it seems to be happy running 1/8 micro stepping, but at 1/16 micro stepping, it just buzzes and I have to switch the voltage to 50% to get it to move. I thought the reverse would be true i.e. 1/8 would require the 50% voltage and the 1/16 would run fine at 25%. Anyway, it sounds like you have to experiment to see what works best. But with an array of 4-5 variables to work with, the combinations of such is exhausting! Any advice or observations welcomed! THX