After some adhesion problems using PLA on my Qidi X-Plus factory building surface, I switched to a mirrored tile, secured by two binder clips in the back corners. All was well until the extruder / nozzle contacted one of the clips while tracing a skirt. My treasured printer abruptly died. I contacted Qidi tech support, and received a prompt response, with a link to a troubleshooting video. The diagnosis was a blown main board. Qidi sent me a new board, an extruder, and a video link for installation. No charge. Mind blown, great service Qidi Tech. My printer is back. No more metallic clips for me. I'll be using blue tape for a while.