I am trying to print with abs, and it loads great then before it is supposed to print the end of the filament turns into a knob and wont feed for the print.
Has anyone else had this problem?
Jonathan
When you say it “turns into a knob and wont feed” … are you referring to INSIDE the extruder? Or… are you referring to some oozing out of the nozzle?
Oozing filament is normal and it’s a reason why the bed probing/leveling is typically done at a cooler temperature (to prevent oozing). This makes me wonder what your start g-code looks like.
If, on the other hand, it’s a problem inside the extruder then I’d ask the fan that cools the cold-end is working and installed in the correct direction (so air-flow is blowing in). This is not to be confused with the part-cooling fan – there are two fans on the print-head and I’m referring to the fan that is normally always running if the printer is powered on. If that fan is either not working or if it is installed backward then the “cold end” of the extruder (which has a cold upper-half and a hot-lower half) then it results in “heat creep” where the cold end gets hot enough to melt the filament before it makes it into the hot-end. This is a very easy fix if this is the case.
Is there are a particular reason why you want to print with ABS? I only ask because it isn’t a beginner-friendly filament. It requires an enclosure and likes to warp off the bed if you aren’t careful. This is because ABS has a high “coefficient of expansion” – so it expands a lot when hot and then contracts a lot as it cools … and this is what causes the warping. The warping pulls the corners up off the bed and you end up with a poor quality part.
That said … LulzBot printers 3D printed parts are printed with ABS (but LulzBot has a LOT of experience doing this). So it’s certainly possible if you’re willing to use a build-chamber and tweak the print profile.
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