On the Original Prusa MINI, even after upgrading the heatbreak with the Bondtech one, the MINI is still clogging. Why?
I've dealt with several issues with my Prusa MINIs, a fact that I'm not exactly happy about. I suppose it's all part of 3D printing, but as reliable as the MK3S is, the MINI is just not there yet.
So far I've dealt with bed leveling issues due to bad PINDA sensors (on both of my MINIs), underextrusion, clogging, leveling, stretched belts, Y-axis belt coming out of its holder underneath the bed, filament sensor clogging/jamming, X-axis misalignment, etc. etc.
One of the more recurring issues is clogging. This time, it's happening even though I've upgraded both heatbreaks to the Bondtech heatbreak upgrade. It's certainly a better heatbreak for the MINI than the stock one, and I highly recommend it! As of this writing (Nov 2021), they are also shipping it with thermal paste, which is a great inclusion. Still, there is one thing that can continue clogging issues after using this heatbreak ...
Either the heatbreak isn't seated properly, or the PTFE tube is still too short.
For me, the PTFE tube was too short, as I replaced it after clearing a bad nozzle, and forgot that it was supposed to be a different one than the original! Unfortunately I had several failed prints before realizing it's likely an issue with the PTFE nozzle being too short. Thanks to TeachingTech's video on his Prusa MINI experience to refresh my memory!
Make sure to follow the guide on seating the heatbreak properly. Once that is completed, ensure that you use the PTFE tube that came with your Bondtech heatbreak, as it is a bit longer than the one that came stock.
If you need to replace the PTFE tube for some reason, you can't use a stock Prusa-cut PTFE tube. Instead, print these parts to make your own PTFE tube that's cut to the right length. Just cut the filament, then make sure to make the beveled edge -- it's perfect!
I used Capricorn PTFE as it's much higher quality than the standard tubing.
After replacing the PTFE tube, my MINIs are back to running smoothly without any clogs or underextrusions. Until next time ...