A few weeks ago I was doing a large print wich failed halfway trough as the printer stoped extruding. The print had bad surface finish and a lot of stringing, problems I have not experienced before.

After cleaning the nozzle it was extruding again and I could print, but the surface quality on vertical surfaces was not as good as before. I tried cleaning the nozzle again, but no change. I concluded the nozzle was probably worn out or gunked up with something I couldn't get out, so I replaced it with a new Prima Creator nozzle. This had no detectable effect on the print quality.

I have also cleaned the gear and idler in the extruder and switched to a new spool of filament. Still no detectable effect on the print quality. (I also cleaned and lubricated bearing all rods and Z-axis lead screw, not surprisingly, no effect.)

One of the test prints was printed from the printers memory before and after the problem started, so I can rule out slicer settings.

Any ideas what could be causing this? Maybe the PTFE tube or some other part of the extruder?


Before_after_microscope.jpgBefore-after_1.jpgFirst_print_to_fail.jpgFirst_print_to_fail_outside_detail.jpg