Slic3r vs Cura - retraction calibration?

Test object I used


I wanted to get rid of hairy strings or to improve printing quality.


And I ended up printing thousands of honeycombs.


Slic3r v1.1.7

First layer





Cura
It actually draws a honeycomb.


Slic3r
Retraction length: 5 mm
Lift Z: 1 mm
Speed: 20 m/s
Extra Length on restart: 0 mm


Cura
Default retraction setting


I played with printing speed between 30 m/s and 300 m/s, retraction speed between 5 m/s and 100 m/s,
retraction length between 5 mm and 0.72 mm, and few other values in Slic3r.

It turned out the layer pattern generated by Slicing program greatly affects printing quality.
If the layer pattern contains a lot of short stroke that requires retraction, jump, and restart, it's
very hard to remove hairy strings by simple retraction setting.
I think very slow printing and retraction speed might reduce or get rid of the hairy strings.

I also found on my printer turning off Z lift greatly helped my prints.

I would think that the strings are being caused by pulling of hot material out the print hole. To that effect, you would want to shear off at 90 degrees at a high rate of motion to snap the feed rather than pull it out. If up and then out, that would offer a chance of material pulling out, yielding the strings. YMMV with the settings.