I’m not able to get a decent crown test out of my MPCNC. I’ve linked the two versions below. What’s wrong to what I see:
The circle seems rather oval to me
The start and end points don't line up
The cross bottom and top are assymetrical
the picture with measurements was done on a ramps 1.4 board with a4988 drivers on 1/16 microstepping, the picture with the double crown was done on a MKS GEN L with a4988 drivers using the same firmware. I've halved the steps per mm value from the one on the MPCNC github, but that's about it. What I've tried:
Increasing belt tension
Increasing driver vref
Using a different mainboard which I know has functional electronics (out of my 3d printer)
Using a permanent marker instead of a pen to rule out any springiness in the mount
All motors have enough holding torque once powered up. Somehow I think that I end up losing steps (doesn't sound like it though) or "distance" in the return trip. I've plotted some squares but these come out about right (except for the 2mm in X that is lost).
Anybody any idea on how to solve this, or what I’ve done wrong?
I’ve thought about it all day, and this could well be the cause. I checked all the screws as soon as I could, but they were fastened correctly.
But I think I’ve found the issue, a wire to the steppers doesn’t work correctly (even though I’ve checked them all for continuity) but I think of one of the steppers only one coil got powered. Is it a bad crimp or something? I don’t know.
When I found the time to crimp a new wire I’ll use it and let you know the results!
And by the way, I am using Ryan’s gcode and pen mount.
Thanks, just you replying gave me the courage to keep on debugging!
