Over-extrusion only on small perimeters

  • Maybe someone with more experience can help me tune my setup to get rid of this small issue.

    I have tuned my extrusion rate and I get really nice accurate parts with perfect infill and top surfaces. Measured wall thicknesses, 100% layers look solid and without over-extrusion whatsoever. I am printing with a E3D V6 fitted with a 0.3mm airbrush nozzle so even a small error in the extrusion rate is visible.
    Also, my retract settings are also tuned in, so that I have perfect quality on prints (no blobs, no holes).
    The problem is when it gets to small island or perimeters (2-4mm²) than it goes crazy into the over-extrusion and I have to reduce manually from the Duet Web Client from 100% to almost 65-70% to get a correct extrusion without blobs and monsters. A perfect test STL would be the hollow calibration pyramid from Thingi…

    A little about the setup:
    -Bowden system around 60 cm long (I still have to measure it)
    -1.75 filament

    • E3D V6 with airbrush nozzle
    • Pressure advance in firmware 0.25
    • S3D with following retraction settings:
    • retract 7.5mm
    • extra restart 0.15mm
    • vertical lift 0.15mm
    • retraction speed 90mm/s
    • coast at end 0.7mm
      no wipe
      Retraction between layers active
      Only retract when crossing open spaces

    Does anybody have an idea where and what I could tune (slicer or duet firmware) to get an even extrusion regardless of perimeter size ?

    Thanks in advance!

    P.S. I have to say.. wow.. this forum grew up so fast! almost 1600 users and 4000 Threads in such a short time!

  • administrators

    Try setting extra restart and coast to end to zero. With pressure advance in use, you shouldn't need them.

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