What could be causing these bobbles on the corners?

What could be causing these bobbles on the corners?

I had the retraction at 2mm as it was what I needed for my old extruder due to slack in the gears. I have reduced it to 0.85 with the new extruder with no noticeable effect. Its almost like its overfilling the corners or the temperature is too high. I’m using PLA, first layer 195°c remaining layers 185°c.

Had the same thing for a while now. Tried to increase retraction, but sometimes values does not stick in slic3r. Tried to increase to 3mm now, but then the filament curled. New tests tomorrow. Currently using my custom Prusa i3 compact extruder and the filament path is a bit bent. Have printed a new with better filament path. Had the problem with standard Wade, think it appeared when I upgraded to latest Slic3r.

This problem started about the same time i upgraded Slic3r. I might try an older version and see what happens.

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@Daniel_Wood What is the retraction speed set to? I deleted Slic3rs data directory and started from scratch. Retraction speed was 300 in my old settings, now they are 30 and there is no bubbles.

@Jelle_Boomstra I’m not sure! I could try kisslicer to see if that creates the blobs

@Tom_Oyvind_Hogstad I started a fresh slic3r and the speed is 30mm/s.

One thing I have found is that it only happens with this material. If I use PLA from +faberdashery it doesn’t happen. The temp is at 185°c so it shouldnt be oozing. In have tried retraction settings from 0 - 2mm in 0.25mm increments with no change.

It seems as though the blobs are created when the hotend stops to change location and the retraction doesn’t relieve enough pressure allowing the filament to continue extruding.

Maybe a faster retraction is required?

If you turn off randomize starting point, then it at least will only appear in one “column”. Could also be a little over extrusion?

I read a couple articles recently that claimed faster retraction is not always better. Sometimes slower is better.