bad surface quality - getting tired of gambling...

Hi,

I'm getting stuck and tired of gambling with changing values and try if I can improve the surface quality

Problem is that I always get those little spots together with the fact that my RepRap creates e.g. straight lines with a length of a few millimeters instead of a perfect circle.

1.) is there any chance to improve the surface?
2.) if you prefer Skeinforge: can anyone please support me with a working configuration file with all the parameters?

MANY thanks in advance!



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Repetier-Host latest Version (1.8 ??)
Slic3r latest Version (0.8.4)
ABS white
heated glass printbed at 95°C
extruder 243°C
0.15mm layer hight with 0,35 nozzle
no slip at the belts, no wobbling axis
glass of the bed is directly on the heater mounted with 4 little clamps

Are you using a Wade's style extruder? If so you can increase your retract speed to at least 30mm/s. That may help with the little blobs. What hot end are you using?

The segments that you are seeing are artifacts of the STL files. They do not have a provision for smooth curved surfaces, and instead have to be described with segments. To minimize that you would have to export the STL files from source at a higher resolution.

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Seems to be a Wade extruder - at least the gear ratio is approximately the same to the ones I found with Google's picture search.
(See attached pictures of my RepRap)

Will test the printing quality with a retraction of 3mm and 50mm/s speed!

"To minimize that you would have to export the STL files from source at a higher resolution." -> I cannot change any export settings at AutoCad
Does changing the "threads" in "Advanced" (2 at the moment) change anything at the compiling stl to gCode?


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pictures:
# the white cover of the printbed is sugar
# the kitchen roll on the top prevents the filament from rubbing against the threades rod

what kind of firmware are you using. I know that sprinter firmware make the circles less round then you could want, Marlin firmware has a built in arc detection making the circles in one go instead of making small steps of the arc in a straight line