How do we know when it is time to replace the nozzle?
Hi, Prusa Support has checked the hot end and there is no leakage. Yet, I keep getting prints with imperfections. For example, black dots, burnt marks, extra filaments suddenly showing up from nowhere in the middle of the print jobs and got pushed around by the nozzle. Sometimes they ended up brown/dark burnt balls but often they got embedded in the prints (often at the front edge or edge of a big circular hole) as brown/dark burnt filaments. I have the i3MK3S for 1.5 years. Often print PETG. For the past three months, suddenly I see more prints with small blobs and zits on the print surfaces. As far as I am aware of, there was no such blobs and zits issue in the past. Are these imperfections caused by the nozzle? If not, what caused the issues?
How do we know it is time to replace the nozzle? I have never taken the nozzle out to clean it but I have been cleaning the hot end.
RE: How do we know when it is time to replace the nozzle?
In your situation, I'd replace it. If that fixes the problem, you know it was the old nozzle. Clean it or toss it. If it doesn't fix the problem, use the removed nozzle as a spare and continue troubleshooting. Nozzles are one of the easiest things to swap, inexpensive, and often the source of annoying problems that can be hard to troubleshoot. When in doubt, swap it out.
RE: How do we know when it is time to replace the nozzle?
Thanks. I worry that if I don't tighten it properly, I may break the hotend which will end up an expensive replacement or cause lava flow.
RE: How do we know when it is time to replace the nozzle?
Thanks. I worry that if I don't tighten it properly, I may break the hotend which will end up an expensive replacement or cause lava flow.
You don't need to be overly worried. Just be sure to immobilize the heater block with a 16mm spanner/open wrench so it can't twist and all should be well. Don't use too much pressure -- I use two fingers to tighten the nozzle -- and be sure not to twist the hotend assembly. Be sure that when the nozzle is fully tightened, there's still a < 1mm gap between nozzle and heater block and all should be well.