The Dreaded X axis stepper error using UC400ETH and UCCNC !!!

[dachopper]

This is so frustrating, so I had another 4-5 skips / jams on the x and z axis doing this parallel job, so I reduced the speed, and the acceleration by 50% , still jamm, turned off the spindle, no jam. Put the spindle power plug and spindle / vfd cable earth on separate circuit ( not going through control box ) still jam.

Then I disconnected the spindle earth ( which runs inside the vfd cable so is probably a massive noise carrier, from the spindle and IE from the machine, and so far no jams.

This ground cable was effectively attaching the vfd noise onto the machine. Since the stepper motors are on the machine, they are then subject to the effectively AC pulse made by the VFD earth, and by the vfd cable shielding.
...


Update:
So disconnecting the VFD ground wire from the frame got me much further into the cut, infact the two medium sized parallel ops finished correctly without any issues, then I ran the really big one, it had a single skip 80% through. So now I'm thinking because the frame is now not grounded as I removed the spindle ground, I'm thinking of running a separately shielded spindle / Z block ground, to get rid of the static or whatever build up is occuring. Could Cat5 cable be useful in that scenario? I'm just trying to find a way to let the noise / static discharge without inducing any further issues...

Nick


So