Saturday, March 21, 2009

Nozzle reconstruction

Took the heater barrel apart and reconstructed, now with help of the BfB tutorial video
The result is a slightly improved, not to say less worse, extrusion. Now without hand-force, it extrudes very slowly. That is no more than four odd millimeters per minute.
Think I leave the RR arest for a while until I have an idea how to improve extrusion. As the sun shines today, it's time to go out and play.

Similar report
Renoir's coach bolt solutio
Zach Hoeken's Pinchwheel Extruder prototype


  1. I have a similar issue with the BfB extruder, very slow extrusion. Checking out the alternatives, the heater and nozzle seem to be similar to other designs, and with additional force it seems to extrude OK. The obvious difference seems to be the drive mechanism.

    There's two main possibilites : the screw drive and the heater resistance.
    My guess is the screw thread can't generate enough force to push the extrusion through and slips. Once it slips, it chews up the filament and can't get going again.

    Give that Nophead's produced some useful figures for the extruder nozzles and forces produced by the pinch wheel design, I'll see if I can measure the output and identify the problem side.


    I assumed it was just me too :-) - I think it probably works fine with the original CAPA (polymorph) but might have problems with higher temp plastics (I'm using ABS).

  2. Renoir,
    Actually ABS is much easier to extrude than CAPA. CAPA is more viscous and is soft and slippery.

    If it feeds properly with a little extra hand force then I would guess the thread is not biting properly. Perhaps the thread is not sharp enough, or there is not enough pressure from the roller.

  3. This was the result after having sharpened the thread, following the tutorial. Though I will give it another try, sharpening it a bit more, when I am recovered.

  4. Read Renoir's radical hack today. A solution I will take into account as soon as I am recovered.