Intermittant Z Axis plunges into hybrid table

Posting for posterity and to help others.

So Thursday (and a few times since I received my S4 in May) I was making a nice 3D walnut sign. Just finished the roughing pass. When the finishing path started, the bit drove down into the walnut work piece. This was a 1/32 tapered ball nose and started dragging in the x axis direction. The spindle tried but the belt skipped under the pressure. (please note that the spindle and the tapered ball nose bit survived). Suffice it to say I restarted this job 2 more times (checking zero) and it would repeat this behavior, but at different points.

So, I stopped and started to investigate. And lo and behold, a broken wire on the Z stepper motor connector. The red one. I’m sure this was the cause of all my z issues where random dives were occurring since I first received the machine. Also had a few machine disconnects where carbide motion said no GRBL.

An intermittent connection.

When I assembled the machine, I made sure the connectors were isolated so as not to move or flex at the pin crimp going into the connector. Was trying to avoid fatigue failure (like when you keep bending back and forth a metal coat hanger and it breaks).

It looks like the part of the crimp on the pin that crimps to the insulation was poor. I believe that under normal handling of this at the supplier and then at shapeoko started the fatigue failure. This then led to an intermittant connection until eventually a catastrophic failure. I’m checking all the other crimps today. Please note that most of the movement occurs near the Z axis carriage so these should be checked first at least. When my warranty is up next year, I’ll probably find a more robust solution for the connections in this area.

So as always, I contacted Carbide3D via email and Oscar contacted me within 1 hour. Quick response!!! We then had a video call. The result was that Carbide is sending me a whole new Z axis carriage with motor, harness, etc. I’ll have to remove the current carriage and my Spindle to reinstall on the new one.

At the end of the day, all mechanical things wear and require maintenance. But a company’s commitment to service and backing their products is critical to me. Carbide3D does exactly this! They have been with me from the start. They sent me 3 aluminum slats for the hybrid table when the router bit drove into the table as part of the mistakes are on us program. They walked me through at the very beginning when i was zeroing on top of the material physically, but I set the Zero on the bottom of workpiece in carbide create not once but 3x’s!!! LOL. Again, Oscar helped me out.

TBH I was totally new to the wood CNC arena. I chose Carbide3D for their service and also for the damn sexy machine they produce. I’ve made some incredible stuff and have also sold some things (see my previous posts). I love my machine and am grateful I made a good choice.

So, check those wires!