Z Axis Calibration failing
My Mk4 suddenly started failing it's Z axis calibration - when I started my most recent print, instead of tapping the build plate, it rammed the nozzle down so hard I thought it might actually bend the plate, and then started grinding the stepper motors in an effort to push it further through. I reran the calibration, including the load cell thinking it might have gotten out of whack. The load cell failed repeatedly until I took the nextruder apart and reassembled it, then it started passing again. But even with the load cell working, the Z axis calibration just rams the nozzle into the print bed and keeps trying to force it through. Do I have a bad load cell? Or is something else going on? The printer has been working fine for about 6 months, in fact it just finished a print which worked perfectly, then this problem.