Filament Tip jam in bowden while unloading
Hi community
Happy new year. Year just started and I already need your help. Over christmas I assembled and installed my MMU2S and struggling now badly with the filament change while unloading.
MMU loads the filament properly but at the first change the filament gets jamed in the bowden at the extruder directli when the tip enters the bowden ( sometimes it made it 5cm in but not more) in that case its even tough to pull the filament string then out with my teeth :-(.
I have 205degC, PLA and tried as read in other threads to increase the pull out speed to 120mm/s and went up with the cooling cycle moves to 4, but same oversizes tips that cant make it back through the bowden.
Any advice how to continue?
Many thanks for your support
Cheers
Markus
RE: Filament Tip jam in bowden while unloading
Tipical tip shape as I get stuck in my bowden
RE: Filament Tip jam in bowden while unloading
Tipical tip shape as I get stuck in my bowden
RE: Filament Tip jam in bowden while unloading
Tried now different parameters on ramming, temp. and tetraction speed, still no success and same problem with tips....
Any advice what mods i should try next? In general i have not muchh drag in the bowdens.
And tightened the two screws to clamp the idler on the bondtech at mmu quite hard for a good tension wirh the springs
RE: Filament Tip jam in bowden while unloading
Hey! I had the same issue. First, what specific company of PLA are you using? If it is especially matterhackers build series, then I don't suggest using it as their filament does not work well on the mmu2/s. My upgrades so far have been using prusament(which is not that much more expensive) and changing out the ptfe tubes to capricorn tubing. Here's a link for it and if you want enough for all the tubes, you need to buy 2 meters. I no longer have issues with jamming.
Another solution is to print some filament oilers for the filament so that the drag through the tubes can be reduced. The ptfe tubes provided by prusa are not great as they are compression fit and strictly rely on low diameter variation of the filament. Hope this helps!