Got my K8800 just before Christmas and built it boxing day. My only issue when building was a slightly loose foot - which I was able to mostly rectify myself. The printer calibrated and printed perfectly first time, with stock firmware. Over the course of the week I successfully did 11 or 12 prints, all small variations on a small (20 mm cubed) model. Got to print 12 or 13 and then everything went pear-shaped. The magnets undid, the printhead came crashing down and continued trying to print. Put everything back together and retried - got halfway through and it happened again. The magnets seem to have weakened substantially. Please help!
It seems to be a calibration problem. also if printer said “CALIBRATION ok” when auto calibration was performed.
Check these things at CALIBRATION ISSUES step per step and precise, and solve or adjust where needed.
Search through my threads (and ones I’ve replied to) and come and share our pain! If you’ve absolutely ruled out mechanical issues, you might want to upgrade firmware, some of us have had success with that (Marlin v2 seems much less aggressive than the bundled v1)
Also, make sure you calibrate before each print, I find that has reduced the number of “incidents” you describe