Bondtech Extruder (e3d hotend) + straight through heatbreak
I was trying to print something with a lot of retractions which kept failing over and over. The failure would vary between either the heat creep issue causing the PLA to gum things up or the Prusa stepped heatbreak getting jammed. So I broke down and went with the Bondtech extruder upgrade and while I was at it I installed the standard E3D heatbreak (that I was about to install prior to finally receiving my MMU a bit over a year ago now).
I was concerned about tip forming with the straight break since that is the whole purpose of the step, but after a few hundred tool changes since the upgrade I have only had one change failure (though that was in the first few tool changes and while I had an extrusion issue going on). The only problem I had with this setup was that after flashing to the BT firmware on the printer it apparently didn't reset the extrusion steps which caused it to under extrude by 40% (though oddly the single color prints I was doing were looking great).
With few exceptions (and only the one failure) the tips are coming out just as clean as with the stock setup. I attribute my success with the switch to the straight heatbreak to the fact that I had things so well tuned before I did the upgrade (3-4k tool changes since my last failure before the upgrade).
Since the upgrade I've burned through about 2kg of filament printing models that I know I would have never gotten through before due to the retractions involved.
I have yet to enable the cutting feature Prusa recently enabled and other than having to fix my extrusion step setting I have not made any changes to the EEPROM or PrusaSlicer settings.
I highly recommend both upgrades (or any extruder mod that fixes the heat creep issue), but I also highly suggest that you have the MMU working well in the stock configuration first.
I swapped recently the Prusa heatbreak with a straight Titanium heatbreak (the titanium alloy has lower thermal conductivity).
I had my dose of jams typical of the MMU2S, but I believe less with the stock heatbreak.
I wait few weeks more before giving the final verdict
Can confirm, Skelestruder w/ titanium TriangleLabs heatbreak and plated copper block. MMU works the same or better than before.
Same here, still getting great tips after switching to Dragon
TheZeroBeast MMU2S firmware...