Musing on Jams (PLA and ABS)

[Agisis]

I recently acquired a Prometheus hot end and have been printing a lot with ABS. I then moved to use PLA and experienced my first few jams almost immediately. Perplexed, I fiddled with the transition zone, fiddled with this, fiddled with that. Then I sat and decided to really think about it. I had noticed that there was some black dust pieces from the ABS in the bowden tube that had been dragged down by the extruder. I also could see a lot of black dust from the extruder having chewed a bit into the black ABS. So, my conclusion was that ABS pieces had gotten down into my hot end, but weren't melting enough to push through at 200c when I was using the PLA, thus causing a jam. I cleaned it all out and no more jams, so that is what I think was happening. Anyone else have something like that happen?

[Glacian22]

Are you using the stock EZstruder? I have a prometheus, and the ezstruder didn't have enough torque, causing it to jam with PLA. I switched to a geared motor, problem solved.

[Agisis]

yeah, using the EZStruder. that seems to be what i am running into potentially too. Hmm....any recommendations on what geared motor setup would work best?

[Glacian22]

I've been very happy with this: http://www.thingiverse.com/thing:744759" onclick="window.open(this.href);return false; ...it's an ezstrude-ish design that I remixed from Nylocke's extruder. You'll need a 5:1 geared nema 17 motor, a bowden fitting like the one that came with your prometheus, a 608 bearing, a spring, and a handful of screws. Or really any other geared bowden extruder will work, this one fits with the ezstruder mounting though and has held up really well. ^_^