Quote Originally Posted by dachopper View Post
So guys,

I am fairly confident that I have diagnosed the problem correctly.

Background - I seem to experience random jamming in the X / Z axis, where by the stepper would loose any huge amount of steps - up to 5 or 10CM of error per event.
It only happened when running parallel type operations with multiple quick Z or X axis toolpaths, or both at the same time. I can run a parallel operation in the Y direction with Fixed Z height, and have no issues whatsoever for hours, but the other direction - within 10 to 15 minutes guaranteed motorStall in Z or X

I changed the power supply from 600W switching, to 700W torroidal, to 1000W torroidal.
I tried 2 x different Gecko drive motherboards
I bought new Ethernet cabling from the laptop to ETH400
I replaced the Geckodrive with a PDMX126 + 5 x Leadshine AM882 digital stepper drivers
I ran the motors under both 3.5 Amp peak setting, and 3.5 Amp RMS setting.
I observed stalls occurring randomly 10-20 minutes in, in every single one of those tried changes
I currently have the Max speed set at 80% of motors peak torque rating, and acceleration set at 10% of the slowest acceleration speed I was able to generate an inertial induced motor stall.
I cannot physically make these motors stall no matter how hard I push / pull / sit on the gantry while it's moving, yet it still stalls mid air unloaded.

After finally videotaping 3 stall events, none of which were cause by excessive speed, loading or acceleration, and also noting the AM882 failed to detect the stall.. I then unplugged the spindle and on the first attempt got to the end of the toolpath without error ( It had failed 100% of previous attempts, within 13:20, 12:00, 9:00 and 17:00 minutes on the recorded occasions - including 2 of those where the spindle was spinning in the air, with and without a tool in, and not cutting anything during the test run but with stalls both occasions. )

Based on the above evidence, that the stalls are not occurring in the same place, or even at the same time, and I can't find any mechanical issue with the machine, It has to be an electrical problem.
It is not effecting the Y axis, and the Y axis cabling does not run anywhere near the spindle cabling, but the X and Z axis runs right next to it the entire wire length.

So, I have ordered some heavy duty VFD cabling ( siemens Protoflex EMV ) and I am also going to re-wire the Z and X stepper motor cables, with some different Foil + wire shielded, and move them to either sides of my cable tracks, with the water lines in the center.

After re-doing the cabling, that is almost the entire electronics replaced, except the ETH400, and stepper motors themselves.

My toolpath is being tested by the UC400ETH retailer, to confirm they do not see any issues from it during the parallel operation, to try rule that out also.

Should be able to test in a few weeks when new cabling arrives, Let you know how it goes.


M_C, the stalls are loud high pitched, and without any movement at all from the jammed axis while the high pitched noise is active, which is normally for the 3 - 4 seconds, or the duration of the attempted move for that axis, until commanded to hold or reverse and it unstalls at that point. I tried straight after it stalled to force it, and it was futile, I would have needed a serious tyre lever to have any chance of making a mechanically forced stall happen with these low speed / accel settings.
OK, so you continue to change/rebuild without knowing what actually is wrong. Maybe you will eventually fix it but without knowing what was wrong. It was waste of my time here since you are not answering any questions. Good luck.