I have Prusa i3 derivative with MK8 extruder and Marlin 1.1RC8 as firmware. I already reduced the default speeds as well as the accelerations. But sometimes when trying to print with BQ PLA filament (220°C), mostly during filling areas, my extruder clicks. The below screenshot of Slic3rs Layers view shows the clicking "lines".
What settings I need to change to avoid the overextrusion in this case?
One trap I've seen that causes the extruder to click, and over or underextrude is that the extruder control is in the wrong mode.
The extruder can be set into relative or absolute mode. If absolute extrusion values are sent while in relative mode, then the system will be trying to push more through than the nozzle or hot end can handle. You'll get blobs, clicking, ooze and it will damage the extruder and hot end.
Have a look at the GCOde - and see what the "E" numbers look like - it they look relative (the same or close numbers repeatedly) or absolute (numbers slowly incrementing). Cura defaults to absolute - but initially was NOT sending the gcode to put my controller into absolute extruder positioning.
Note also - this is separate from the XYZ absolute/relative positioning modes.
M82will put the extruder in absolute mode.
M83will put it back into relative mode.