MMU + TPU = SAD!
I've printed a number of items in TPU (Shore 95a) with my MMU, mixing materials or just pure.
I have found that on ejecting (unloading) the filament, the MMU can wind the filament around the MMU's Bondtech gear, making a tangled mess that's hard to fix.
Had anyone tried/looked at/thought about making the cut-out for the MMU's gears tighter, making the filament path more constrained?
It seems like a big job so I wanted to check if anyone else has looked into it before I put too much time here.
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Re: MMU + TPU = SAD!
It's on my list of things to do, but I haven't really started it yet, no will I for some time. I'd say go for it.
Re: MMU + TPU = SAD!
Maybe use this spoolholder : https://www.thingiverse.com/thing:3252111
it pulls a little bit on the filament and the pulley does not have to push the filament back.
Re: MMU + TPU = SAD!
TPU is a major issue on the MK3 in general. Ninjaflex is shore 85A which is almost the softest TPU you can get for 3d printing. the mk3 extruder basically freaks out with it and send it flying left and right outside the bontech gears.
the same ninjaflex on the MK2S works no problem. it has to do with the how prusa moved the PTFE tubes away from the bondtech gears and that stupid design of the filament sensor you don't have a nice straight shot into the extruder in the MK3 like you have in the MK2S
some months ago a member redesigned the extruder body to work with soft TPU. however the design didn't last it melted due to the extra heat of the older R2 extruder design then there was a little fix piece you tried to put into the lower part of the extruder to raise up the entrance of the TPFE tube to force the TPU into the extruder without it shooting out the sides. after a few hours that part would melt as well (unless you made out out of nylon) then you were back to print failures as TPU had to go down really hot and really slow.
i don't think anyone bothered redesigning the TPU fix with the R3 extruder body and fan redesign.
the problems with TPU and the MK3 is another reason the MK3 is bad compared to the MK2/s
so many people focused on the #602 inconsistent MK3 problems and other issues with the extruder that they have been bogged down just trying to make PLA look decent and haven't even jumped on all the other things the MK3 can't do right. so many people are jumping ship and dumping the Prusa extruder for something else and just reusing the frame and rambo to make a better printer, the latest is the BMG extruder swap out.
i have been running NinjaFlex on my MK2s with no problems for about 2 years now as a comparison. MK3 and TPU don't mix.
i can say that my replacement of my bondtech gears with a similar bearing idler setup from the MK2 on the MK3 drastically improved my MK3 output quality
“One does not simply use a picture as signature on Prusa forumsâ€
Re: MMU + TPU = SAD!
TPU is a major issue on the MK3 in general. Ninjaflex is shore 85A which is almost the softest TPU you can get for 3d printing. the mk3 extruder basically freaks out with it and send it flying left and right outside the bontech gears.
the same ninjaflex on the MK2S works no problem. it has to do with the how prusa moved the PTFE tubes away from the bondtech gears and that stupid design of the filament sensor you don't have a nice straight shot into the extruder in the MK3 like you have in the MK2S
some months ago a member redesigned the extruder body to work with soft TPU. however the design didn't last it melted due to the extra heat of the older R2 extruder design then there was a little fix piece you tried to put into the lower part of the extruder to raise up the entrance of the TPFE tube to force the TPU into the extruder without it shooting out the sides. after a few hours that part would melt as well (unless you made out out of nylon) then you were back to print failures as TPU had to go down really hot and really slow.
i don't think anyone bothered redesigning the TPU fix with the R3 extruder body and fan redesign.
the problems with TPU and the MK3 is another reason the MK3 is bad compared to the MK2/s
so many people focused on the #602 inconsistent MK3 problems and other issues with the extruder that they have been bogged down just trying to make PLA look decent and haven't even jumped on all the other things the MK3 can't do right. so many people are jumping ship and dumping the Prusa extruder for something else and just reusing the frame and rambo to make a better printer, the latest is the BMG extruder swap out.
i have been running NinjaFlex on my MK2s with no problems for about 2 years now as a comparison. MK3 and TPU don't mix.
i can say that my replacement of my bondtech gears with a similar bearing idler setup from the MK2 on the MK3 drastically improved my MK3 output quality
Really haven't had any issues printing TPU with my MK3. Check out some of my posts.
Re: MMU + TPU = SAD!
Really haven't had any issues printing TPU with my MK3. Check out some of my posts.
run ninjaflex? report back.
Harder TPUs do work because they are basically like PLA. soft materials the MK3 turns into a meat grinder.
“One does not simply use a picture as signature on Prusa forumsâ€
Re: MMU + TPU = SAD!
Really haven't had any issues printing TPU with my MK3. Check out some of my posts.
run ninjaflex? report back.
Harder TPUs do work because they are basically like PLA. soft materials the MK3 turns into a meat grinder.
I ran Ninjaflex recently, actually. Got about half way through a phone case and it jammed, filament sensor caught it but it had already missed a couple layers. Had to run it super slow. Can the Mk2S print ninja flex without issues?
Re: MMU + TPU = SAD!
TPU is pain to print independent where MK2/MK2S/MK2.5/MK3 all of them can jam with TPU and all of them can print successful (Ninjaflex). It's beneficial to have a slightly longer teflon tube which is almost touching the gears.
This is the only modification which helped me on MK2S, MK2.5 and MK3 equally. Printing Ninjaflex with 100% success rate on my machines. It was a long way until I got there with the print settings, object understanding and the spring tensions on the gears. But from the hardware perspective everything was already there from day one.
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
Re: MMU + TPU = SAD!
Can the Mk2S print ninja flex without issues?
yup the only thing i do on my MK2S to print ninjaflex is i turn out the idler screws 1 full turn so the tension is lighter. when finished, i turn the bolts back 1 turn and continue printing pla, abs, petg, etc...
you use glue to hold the ninjaflex to the PEI sheet and when complete i take a brush, dip it in water and brush it on the bed so it dissolves the glue and the TPU comes right off, no need for a flexible steel bed.
“One does not simply use a picture as signature on Prusa forumsâ€