Printer Maintenance log

 Went about a whole year without doing any serious PM and calibrating on my Ender 3, aside from minor bed level adjustments.  It finally started seeing problems after running 8 hours a day for a whole year, with a week of rest per month when I left town.  Fortunately these are fixable along with most parts of the Ender.

Space between lines - not good!

The first thing I noticed was spaces between lines on the top layer, then failure to extrude.  At first I suspected a clogged nozzle, then I thought the table had somehow shifted away from print head causing thin lines.  I guess it was a combination of both (and I suspect a weakened extruder feed might be the next problem area in a few months).  I attempted to disassemble the print head for cleaning but then the aluminum heat sink broke from the heating block!  There was burnt carbon crud in the nozzle and hotend.  Luckily I had a spare printhead with hot end assembly.  The old Bowden tube was trimmed to it's extreme shortest length from previous maintenance.  Everything had to go.  I also discovered that saving brass print nozzles and cleaning them is a waste of time since you can buy a whole bag of 10 for $15.

Bowden tube should touch the nozzle.

After installing the hot end assembly and leveling the bed, I was getting horrible stringing.  It was from where one layer ended and the printhead moved to the next layer, leaving a trail of residual filament behind.  Settings needed to be re-adjusted.  The first thing the experts say is to modify retraction settings.  I used this guide to help troubleshoot.

Stringing like dog fur.

Modifications made and results:

• Changed extrusion temp from 217c to 208c - no change.
• Reduced print speed from 40 to 35 - no change
• Increased retraction distance incrementally from 5 to 10 - success!
• Retraction speed from 50 to 55 - minor improvement.  It should be noted that this might be too fast and cause the extruder gear to rough it up and cause wear.
• Changed top layers to 2 from 0 (might have been accidently changed at some point?) - no change
• Infill gap overlay from 30% to 70% - very minor improvement.

Troubleshoot by incrementally changing settings.

Helpful troubleshooting links:

All3dP - Fix stringing guide
All3dP - Guide to gaps between lines and other layer problems