Hey Andrew,
this is a frequently reported issue. See here for examples. However the possibles causes can vary.
The main causes are
-
connectors without strain relief (solution: retrofit serious cable management),
-
the Z curly cable breaking internally after one year of use because it is not made for permanent motion (solution: retrofit serious cable management),
-
the effect of EMI from the router on the unshielded
stepper motor cables (solution: retrofit serious cable management, replace EMI-emitting unearthed router by earthed spindle with fully shielded cabling and VFD in earthed control cabinet, finally: ground the machine correctly). Also besides shielded cables, snap-on ferrite cores can reduce EMI.
The manufacturer offers these Support FAQ documents for your issue:
- Z Axis Moving Unexpectedly (Cutting too shallow or too deep)
- Troubleshooting: Rail is getting hung, stuck, or out of alignment (x35/x50 machines)
Welcome to the forum!