Steppers in Series

I just got back into using my MPCNC machine again after rebuilding the centre gantry - I found it wasn’t very square for some reason the combination of parts from my old and new 3D printer weren’t very square.

Since I built it I was having heaps of trouble with the X/Y axis skipping and generating lots of vibration. The endmill was chattering, resonance through the whole thing. The frame brackets were cracking all a bit of a mess.

I cut down the Z axis as I thought that was two high. Adjusted the driver voltage, started playing with the microstepping jumpers. I’d originally bought the most powerful NEMA17 steppers I could source. (59Ncm)

Nothing really helped, so I figured that was just the way it is, and ran the machine very slowly with a shallow cut depth and it was mostly okay.

I came back to the forum here and started doing some reading again and came across the bit about wiring the steppers in Series. So I did that and now my machine is a completely different beast. (Since then I’ve seen the dual drivers / auto-squaring - I’ll leave that for another day)

I think the graphs on this site sum it up. Double the torque at slow speed in Series.

I got a massive improvement and I can now run at the recommended feedrate, no skipping, good accuracy, resonance gone and no problems with the cut depth. I can’t really understate how much of a difference this made for anyone having similar issues.



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Wow, I wish I had found those graphs 3 years ago!