renderbuoy

Well it looks like you were 100% right, gr5. The BP was too close to the nozzle. I haven't completely fine tuned this, but have been getting much better results by adjusting the BP downward a bit. I have been printing at 220deg, and when I accidentally let it run at 210deg, I noticed the same symptom...skipped steps. Once I heated back up to 220deg, no more skipping. Sensitive little thing. I also took note of how far the shaft counter-rotates when skipping...it appears to be 1/8 rotation or less. And the reason I wasn't seeing the problem on the other prints was because they had a relatively small footprint as compared to my rectangular test model. There wasn't enough travel distance for the pressure to build up. Thank you so much for the help!! I feel like I am getting somewhere now. And thank you Takei for weighing in as well. Glad to report I haven't suffered a clog yet, knock wood!

gr5, thank you for the response. This is an interesting theory. Are you saying that if the stepper motor misses enough steps (say, because the filament is not moving through the nozzle as fast as the extruder is trying to push it) that it will eventually move quickly in reverse about half a revolution, basically taking the shortest and easiest path to the point in the shaft rotation that the gcode is telling it to go to? Not knowing much about stepper motors and such, this sounds plausible. But here's the rub... I just printed several other prints (robot, coffin's cube) with none of the retracting (or step-skipping) happening. And I have not changed the level of the BP at all, or changed any other settings. Thoughts?

I am having very similar problems, but the extruder is not clicking, it is doing full retractions. Also, it doesn't appear from the quality of the print that there is an excess of material being laid down anyway. I initially unchecked the "enable retraction" setting in Cura. Then I changed expert settings in Cura to min travel = 1000, min extrusion = 1000. In spite of this, I got the EXACT same result as the first time. The third test was to also change retraction settings on the machine directly to speed = 0, length = 0. In spite of this additional step, I got the EXACT same result again. The machine just retracts every few lines, regardless of ANY settings. Any assistance here would be GREATLY appreciated. Thanks in advance!