Nozzle contacts print/print bed
I ran into this issue to the detriment of a nozzle and a PEI sheet bed. I believe that I have solved the issue and am sharing in hopes of saving other the pain.
Symptoms:
- Wavy pattern on flat parts, see photos below.
- Nozzle running into print and peeling it off the bed.
- Nozzle contacting the print bed, scraping it and then getting stuck and causing a divot.
Causing the divot also broke the nozzle where the tube meets the brass end. Really stinks. I thought so too.
What happened? I had tried printing TPU and thought I'd messed up the extruder. Removed the hotend and nozzle (incorrectly resulting in having to replace the thermostor), then I started running into issues and they kept getting worse. I receive my Mk4S upgrade which, thankfully, includes the CHT .4 nozzle, and the test print did not go well and I stopped it, taking the pictures above. Next day I tried another print and noticed that the nozzle has started to slide out of the heat sink.
Solution
I found that I had tightened the lower knob onto the wires (even though the instructions cautioned about that, but I wasn't using the instructions, my bad). I have reseated the nozzle, made real sure all wires were clear, and tightened down both knobs real tight. Test print is doing great. Next print will probably be the nozzle changing tool