Extruder delayed jam

Hello! I'm almost done building a shapercube, but having some problems with the extruder where i can't find much about on the forum.

Before I start to explain, I notice the equipment you use had a lot of influence on the problem solving; so some information about my printer:
Shapercube 2.0
I use a Wade's extruder
PLA filament (3mm).
My hot end was delivered pre-ensembelled: [www.reprapsource.com]
I tried different temperatures and different kind of filament (ABS and 'soft PLA' [www.2printbeta.de])

At first, the extruder runs fine at all speeds. But after some time it jams all of a sudden. The wheel keeps spinning, thus the hobbed bolt starts scratching in the filament. When i put the extruder in reverse, it does come out quit easily. Because i tried this on different temperatures and with different materials I think it is something in the hot end.

If anyone could give me some tips about how to check my extruder I would very much appreciate that!

Mathijs

This sounds like a hobbing problem. What I have determined is that the recommended 3mm Tap threading for hobbing the bolt is not sufficiently deep. The tread is too fine, resulting in "teeth that are not very deep, thus they tend to get clogged up with any small amount of plastic dust. Get a larger tap, 1/4" 20NC. I've had really good results with this.

I would suggest that when you get a jam switch everything off and let the feedstock solidify in place.

Once everything has cooled down dismantel your extruder and examine the profile of your feedstock. Is there some swelling of your feedstock diameter before it enters your thremal break or the barrel etc.

This will help you narrow down the cause of your jam.

Of course it could just be a hobbing problem, but I would guess not.