Mini 1 Z-axis fail

A few times of late, my Mini 1 prints have failed part-way through when the nozzle suddenly loses its elevation, and descends into the build plate with a terrible grinding noise. I’ve never witnessed this failure directly, but am usually near enough to hear it happen, and to quickly hit the kill switch before reconnecting and raising the nozzle. Subsequent prints are usually fine, though I’m not sure about my poor build plate.

Anyone else have this issue? Could it be a software, buffer, or USB communication issue?

That is a good indication that the Z Axis driver chip hit thermal limits and lost a mini step. That chip is pretty loaded having 2 motors running off of it, and can heat up.

Hmm, or a whole lot of mini-steps. Thanks, that makes sense. It all worked fine after a bit of a rest, so I guess it cooled down sufficiently.