Air bubble in the flow after retraction, never got rid of it

  • Hi everybody

    I got fed up with these cursed air gaps in my lines after a retraction. How ever I try to change speeds and distances there is allways a "snap" sound and a couple of mm (or much more) empty space in the line when starting to extrude after retractions. Also oozing is quite horrible with the materials I use, ABS and PETG.

    I run 0.6-1.5mm nozzles on Titan V6 hotends and usually the minimum layer height is 0.2mm so the flow is quite fast and it just can't be slower for my needs, the parts are big and times often half a week already. I'm not going crazy with the temps neither, staying in the scope of the materials but surely often in the top end.
    Of course the problem is a lot better when going on low temps, but as you all understand it's not allways cool to be cool 😉 especially when printing faster.

    And NEVER have I got rid of the "Snap kraccle n pop" that in extreme cases ruines the print since on top of the empty spot is laid the next empty spot and so the error just keeps on growing.

    Any ideas? My kingdom for a solution!


  • I found that I was getting that by retracting too far. So now I am using 4mm of retraction with my titan+v6 bowden setup. The v6 does appear to be rather sensitive to over-retraction.

  • Another thing to check is to make sure the filament is dry. Wet filament will crackle like you describe.

  • administrators

    When you hear the snap sound, can you see the extruder gear jumping backwards?

  • Hi

    Filament is dry, no other snapping than the described type. I have experience on wet filaments so I know this is not the case.

    There is no skipping or other weird movement in the pulley.

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