So I tried all the by the book methods to get it unclogged but nothing worked. I took it off the machine, took the whole hot end apart, removed heater, thermistor, and nozzle, everything until I just had the bare block with the plastic jammed in the main throat. My nozzle was actually fine, but it was the plastic in the main block that was literally glassed in. I ended up taking a torch with map gas and heated it until the ABS bubbled, I then had a scmall Philips screw driver that fit the 3mm diameter hole almost perfectly and I worked and pushed the plastic ABS out from the top through the bottom (nozzle end)…even with heat it was thick and goory and clinged all along the sided of the brass shaft. Have no idea how it got so jammed in there but obviously it was probably heated somehow, ie where it’s supposed to stay solid and cool, where the heatsink and fan are, it turned molten and just compressed and compressed.
Anyway, after I got most of out, I let it soak in acetone overnight to remove any remaining plastic, then blew it out with compressed air in the morning. It looks good as new. I put everything back together and put some antiseize on the threads for the nozzle. Also, I changed nozzles with some 4mm I had ordered from 3d industries.
Fired up the printer, tested for flow and all was good. So far I’m a few hours into the print with no issues. But I’m still worried about heat creep. Although since it works now, it basically means there was a problem with the original nozzle, maybe it got clogged and heat creeped up due to the plastic not flowing through, then it glassed everything in higher up.
NOW…this brings me to my next issue and I hope researchers can chime in here because I’m asking myself, is the Hex Hot end really a good or optimized design to begin with, are we to believe that a tiny heatsink and a micro fan can keep a 300 degree heater at bay???
Isn’t the whole crucial aspect of a Hot end to have a very sharp transition between Solid and Molten state, ie a really sharp melt zone and a very separate cooled zone to keep the upper part of the filament in a solid state to help push it along? I’ve attached two pictures illustrating this, couldn’t you increase the size of the heat sink and add a very large heatsink or insulator to act as a break so heat can’t creep back up? I’m just surprised at the current designs of hotends and I’m wondering why they’re not designed like this, unless I’m missing something… Also, I’m not a fan of relying on a fan for keeping the cool zone maintained, no pun intended. To me, it’s overcomplicated and an area for failure. Would it not be possible to do it passively with a large enough heat sink or insulator, like the budda does? I might try to experiment with a few designs but I want to know if anyone has tried this already…will save me some time and money.