Following on from my poorly printed nude sculpture, earlier today, here is the hobbed bolt and the end of the 3 mm PLA filament, removed from the printer following the last print.
What do you think? Too little pressure?
It’s not grinding or slipping it looks like. Remember: Under-extrusion isn’t always caused by a slipping bolt, sometimes you just need to adjust your e-steps-per-mm on the extruder so it moves more plastic through the nozzle. Under/over extrusion can also be caused by improper filament diameter, mismatched nozzle diameter, etc.
That looks very ok to me. Lately for me the main reason for incorrect prints was the varying diameter of the filament that i either did not measure (lazy) or which changed over the length of the filament.
Another thing to consider is if you have callibrated your E axis? And if you have used the corrected filament diameter. It makes a huge diference.
The prints definitely look like the extruder flow is intermittent. Perhaps a bad connection to the motor or the small gear is loose on the motor shaft.
Also the retract speed too high or the extruder acceleration too high might cause it to stall.