Filament doesn't unload completely, bends sideways and blocks next filament
When switching from the second filament to the third filament, it doesn't pull the filament out of the selector far enough, then when the selector moves to the third filament spot it drags the second filament with it, bending it sideways and blocking the third filament from entering the selector. The first time it happened I didn't realize what had happened but had a hard time pulling out the filament and when I finally got it out noticed the end was pretty mangled. This time when it happened I saw the filament stuck sideways. Any clue what could be causing this? I got the MMU2s built on Saturday, and have not yet managed to have a single successful print, mostly issues with the filament grinding which could potentially be the cause of this as well. I couldn't find any posts on here from others having this specific issue, so not sure if I have some defect in the printer or something. I did notice a help article on the selector getting stuck that mentioned it though.
RE: Filament doesn't unload completely, bends sideways and blocks next filament
if there is a thin spot near the end of the filament the finda can sense "end of filament" early. the MMU waits for the finda to sense the end of the filamant and then retracts enough to clear the selector. either the detection is happening before the actual end of filament or ther is too much back pressure on the filament exiting the MMU idler or the idler pressure screws are too loose
RE: Filament doesn't unload completely, bends sideways and blocks next filament
Hello, this normally happens when:
- The original teflon tube that connects the MMU2 to the extruder has been replaced with another that is not exactly the same length
- the extracted filament has formed a ball shape with long strings on the end and this do not move/fit inside the teflon tube, the motors are no able to extract it correctly, and even the stringy part may block the mmu2.
- the cover screws of the MMU2 are too tight and the filament shifts between rollers and can-t move correctly
- there is too many friction on the telflon tubes from the buffer to the mmu2
check if one of this cases apply to you.
Regards