Failure of stepper motor

[orob]

So… I have an mpcnc with probably 30 hours of cutting time on it, mostly 10-20 minute jobs until lately a carve/pocket job that has been taking about 4 hours. It has run half a dozen times now and it is really a travelling salesman problem. It needs to be optimized, but 75000 lines of gcode is unwieldy for me at the moment. My solution: turn up the speed to 11. It was cranking at 2750 mmpm cutting foam and the lcd dial was at 115%. It has cut about 10 hours like this. Maybe cranking the speed was a bad idea, but it brought down the cut time significantly.

Then one y motor stopped. I just received an order with a few more steppers for another build and I swapped one and the other y motor is now skipping steps. I’m going to swap it out as well likely and arder a few more, but this seems odd.

These new ones are from v1. The old ones are not… The bad motor is easy to turn for half of a rotation and hard to turn for half a rotation. Any idea what causes a stepper to fail? How do we prevent future motor failure?

Is there more maintenance beyond cleaning the rails that must be performed to keep it running like new?

Thanks for any thoughts and feedback.

[vicious1 (Ryan)]

I have never heard of a stepper failing under our or even 3d printer use cases.

[orob]

Thanks for the sticker and for the quick shipment. That stepper saved my order. The grubs on the opposite side needed to be torqued. The motor skipped with no load on it after I pulled it from the truck and drove it manually with the lcd control. I have since disassembled it and the bearings spin smoothly. Odd.

On another note, I had some toddlers over helping me clean my car and they were mesmerized watching the mpcnc do it’s thing. One older kid said it was “so satisfying” to watch.