Hi!
I've just finished building my first 3d printer. It's a Prusa i3 with e3d bowden hotend. I'm now trying to get the settings correct.
I'm using the hollow pyramid to calibrate the retraction settings. It print quite nicely, but some times the hotend creates a blulb.
This happens randomly. Its like the extruder extrudes to much plastic sometimes.



Im doing 5mm retraction @ 70mm/s with -.2mm restart distance.
The material is PLA extruded at 190°C. Printing speed is at <40mm/s.

Any ideas why i get this problems?