Machine Lost Zero

Hello, I’m new to CNC and I’ve only had the Onefinity for a short time and have gotten a few successful cuts done but my latest one has started to give me problems. About 6 minutes into my first tool pass the Z axis suddenly moved up and was above the work piece. When I stopped (not emergency stop) and told the machine to return to zero it was off in all axis. So I manually re-zeroed X and Y and used the probe to reset Z, but upon restarting the program the machine went rapid full down in the Z axis driving the tool through the workpiece into the spoil board before I could hit the emergency stop. Not sure what could have caused this. Just wondering if anybody could give me any thoughts on what I’m missing.

Hello … also very new to CNC. I had a similar experience tonight. I was doing test cuts to try different feeds and speeds. I had just done an “air carve” to check the cutting path and everything looked fine. I reset the Z axis zero to the surface of the work piece and started the program. Before I could dive to the eStop, the bit had plunged through the workpiece and about 1/2" into the spoilboard. (The brand new spoilboard that I had just surfaced and cut a grid into !?! ) Ahhh … that’s the world of CNC. Anything I could have done to mess up the probing process on the Z axis ? I reset everything and tried again and this time it went fine. Albeit that I created a lot of chatter with the speed I was trying to cut at. All the stuff I read about chip load and feeds and speeds are pretty aggressive for this size machine. Thanks.

One of the most common mistakes for a failure like this would be accidently zeroing your Z off the waste board when you have specified the top of your stock when you created the gcode file. If you’re positive that you zeroed it correctly then the next thing I would suggest is to check all the cable connections to the Z stepper motor, make sure all the pins are fully seated in the connectors and they’re all tight. After that you start getting into sources of EMI/RFI and static electricity as potential sources, try to keep the stepper motor wires away from the power cords as much as possible, if you use drag chains consider shielded wire for the spindle. I would also suggest you ground one of the legs of the Onefinity to give static electricity a path to ground. Consider a conductive hose for the dust collection if you don’t have one already there have been a few reported cases of the machine going wonky after an ESD event.

I had an accidental Z probing failure myself last week, since this is a brad point bit I decided to zero it manually, I set the height where I wanted it and never hit the zero button… hit play and drove the bit into the workpiece, not sure how it stayed together.



Thanks Derek for taking the time to share your suggestions.

I’ll go over these and make sure I’m good. I’m also going to make a “preflight checklist” to make sure I do everything I need to do before pushing the play button. Thanks again.