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Yveske
(@yveske)
Estimable Member
Can't load filament

Can't feed my filament (Prusament PLA) down to the nozzle.
When I disconnect the bowden tube from the printhead and hold it out in a straight line, it will feed through.
It seems like the PLA is too stiff and rigid to follow the bends in the bowden tube.

Has anyone encountered this also and have a solution?

Thanks,
Yveske

Having problems with bed adhesion every morning......
Posted : 03/04/2020 5:38 pm
Martin Stoufer
(@martin-stoufer)
Estimable Member
RE: Can't load filament

I've encountered something similar to this, but was caused by the tip having a bulb too large to fit easily through the tube. Once I put a cleaved edge on it, the filament passed through just fine.

How does the filament feel outside of the tube, is it really stiff or still pliant to bending?

Posted : 03/04/2020 6:47 pm
Yveske
(@yveske)
Estimable Member
Topic starter answered:
RE: Can't load filament

Prusament PLA is wound very neatly but also very tightly on the spool and the filament wants to stay in the same curb.
You could even make a small leaf spring out of a small strand of filament !

It's not a retraction problem because it fails before I even have a chance to start a print and I could even kill a man with the tip on that filament.
I'm still doing preliminary testing before I commit lots of time and filament to failed prints.

It passes through the MMU without much friction, but as soon as it reaches the first bend in the bowden tube it grinds (literally) to a halt.
The higher the Z-axis, the tighter the twists in the bowden tube and the less distance the filament travels.

I've tried replacing the bowden tube with a Capricorn version and just now implemented the mods suggested by jfromel, but all to no avail.
( https://www.prusaprinters.org/social/39942-jfromel/prints)

I'm at a loss,
Yveske

Having problems with bed adhesion every morning......
Posted : 04/04/2020 4:37 am
Yveske
(@yveske)
Estimable Member
Topic starter answered:
RE: Can't load filament

Solved it by moving the MMU2S 3cm back. I've cut the standard slanted MMU holder vertical in the middle of the upper inner fillet, moved one half 3cm back horizontally and put in 2 horizontal beams to reconnect both halves. This makes the filament drop in almost vertical instead of forcing it into an S shape.

Now trying to fix filament tips which are too thick to unload...

Attachment removed
Having problems with bed adhesion every morning......
Posted : 18/04/2020 6:25 pm
Martin Stoufer
(@martin-stoufer)
Estimable Member
RE: Can't load filament

Yveske, well done!

Can you send us a photo of the final re-assembled product? I'd like to see that new truss in action.

Posted : 20/04/2020 7:08 pm
Yveske
(@yveske)
Estimable Member
Topic starter answered:
RE: Can't load filament

The MMU is a modified version of the mods by jfromel (see link above). I've replaced the brass inserts with modelled threads (Amazon didn't/doesn't deliver (certain) goods to Belgium due to Corona). I don't know if these mods help or not, I haven't taken the time to strip down the MMU again to reinstall the original parts.

Having problems with bed adhesion every morning......
Posted : 21/04/2020 5:56 am
Yveske
(@yveske)
Estimable Member
Topic starter answered:
RE: Can't load filament

In attach the untested version 2 of my holder.
I had to use slightly longer screws to reach the nuts in the MMU using version 1.
In version 2 you should be able to reach the nuts with the original screws.

Having problems with bed adhesion every morning......
Posted : 21/04/2020 6:21 am
Yveske
(@yveske)
Estimable Member
Topic starter answered:
RE: Can't load filament

Attach in Zip format (Fusion + stl)

Attachment removed
Having problems with bed adhesion every morning......
Posted : 21/04/2020 6:40 am
CybrSage liked
Yveske
(@yveske)
Estimable Member
Topic starter answered:
RE: Can't load filament

Also available on: https://www.prusaprinters.org/prints/30254-mmu2s-holder-extended

Having problems with bed adhesion every morning......
Posted : 21/04/2020 2:03 pm
CybrSage liked
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