Filament goes wild on reel with long prints - Mini 2

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saildude
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Filament goes wild on reel with long prints - Mini 2

Post by saildude » Tue Apr 16, 2019 11:33 pm

Finally got my printer printing

When printing over maybe 2 hours the filament on the 1KG reels gets loose and wild and falls off the reel.

I have added a simple guide to the top of the printer with the guide edge just forward of where the filament goes into the print head - this does help but not all the time

Any solutions or suggestions how I can keep the filament from falling off and messing things up?

I want to do some prints that are 4 to 8 hours (multi copies of the same object in some cases) and just want to start the print job and not worry much

Thanks

monsteroyd
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Joined: Fri Jul 06, 2018 3:30 pm

Re: Filament goes wild on reel with long prints - Mini 2

Post by monsteroyd » Wed Apr 17, 2019 6:08 pm

???

I've never had that happen. Did you pull the spool holder up so it is sticking straight up?

Can you post a picture of your printer? I cannot believe how much trouble you are having with a Mini 2.

Monty
Lulzbot Mini 2

saildude
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Re: Filament goes wild on reel with long prints - Mini 2

Post by saildude » Thu Apr 18, 2019 12:29 am

Yes I have the holder set correctly

Will see if I can take a picture of the printer and figure out how to post the picture Thurs or Friday

Thanks

Maybe the printer does not like my gray hair?

monsteroyd
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Re: Filament goes wild on reel with long prints - Mini 2

Post by monsteroyd » Fri Apr 19, 2019 9:43 am

Well you are lucky, my hair turns gray, it falls out. So that is a possibility, but I'm also what they call a senior, so maybe not. :)

Monty
Lulzbot Mini 2

jim2386
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Re: Filament goes wild on reel with long prints - Mini 2

Post by jim2386 » Mon Apr 22, 2019 9:52 am

Is it possible your filament is twisting as it prints? I had this happen with ninjaflex using my old flexystruder toolhead. You can test this by taking the spool off the holder while it's printing and rotating the spool either clockwise or counter clockwise (not through the axis the holder goes through). Kinda like how you had to spin the old handsets for corded telephones to keep them from coiling up and tangled.

If this is what's happening, the cause is the hobbed bolt isn't centered correctly in the toolhead. It imparts a small twist and the filament moves through the head. During shorter prints you wouldn't really notice much, but the longer it runs, the more time it has to twist the filament.

Just a guess.

saildude
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Re: Filament goes wild on reel with long prints - Mini 2

Post by saildude » Mon Apr 22, 2019 11:57 am

interesting thought - will check for the twist

Seems to be that the filament being quite springy it seems to loosen up on the reel during a long print - seemed to get a bit better when the spool gets a bit down - the sides of the spool act a bit as side guides

Thanks

fastrobplus
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Re: Filament goes wild on reel with long prints - Mini 2

Post by fastrobplus » Mon Apr 22, 2019 1:21 pm

Is this by chance Verbatim brand filament? I've noticed that it will turn beautifully for a time, then explosively expand on the reel at some point. I also notice that Verbatim is a slightly different blend of PLA and the wind on the spool is different than other brands. This problem seems a bit worse for the Mini as the filament goes top down into the extruder versus the Taz, where it goes bottom up from the spool.
Verbatim is my absolute favorite brand but I've recently tried others because of this occasional problem and they don't have that issue (or have is much less) but the winds on the spools of other brands seem much worse. I was surprised that both Filementum and Polymaker have given me reels where there was a tangle bad enough to stop the spool from turning.

saildude
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Re: Filament goes wild on reel with long prints - Mini 2

Post by saildude » Mon Apr 22, 2019 1:45 pm

Yes it is Verbatim Filament

Yesterday the spool got so messed up that part of it wound back on itself 180 degrees and really messed things up - took me 20 minutes to straighten out the coil and rewind the messed up part

kmanley57
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Re: Filament goes wild on reel with long prints - Mini 2

Post by kmanley57 » Tue Apr 23, 2019 7:00 am

The unrolling tends to be due to re-spooling from a larger take-up spool on to the smaller retail spools. It 'remembers' the bend it has/had on the bigger spool while it was still warm. But once the filament cools and is re-spooled onto the smaller rolls it will try to return to the larger bend. (Aka - Spring action in the plastic)

The farther it is on the outside of the bigger spool the more it will try to return/uncoil.
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