Filament 'pigtails/barrel roll' between spool and extruder as print runs
 
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MileHigh3Der
(@milehigh3der)
Honorable Member
Filament 'pigtails/barrel roll' between spool and extruder as print runs

Don't know if pigtails is the right word.  I have a MMUs/MK3S that as I use a filament, the straight line of filament gets 'barrel rolls' in it.  This seems to sometimes  cause more friction and then feed issues.  I can take the spool and 'twist' it to take some barrel rolls out, to one degree or another.

Anyone else  see this?  Is there a solution to keep it from happening?

Napsal : 03/08/2020 10:51 pm
jsw
 jsw
(@jsw)
Famed Member
RE: Filament 'pigtails/barrel roll' between spool and extruder as print runs

Coincidentally, I have a print running right now which is showing this.  It's a mostly full roll of Solutech PLA.

Twice I've had to take the spool off of the stock spool holder and give it a couple of twists to let it feed straight.

Napsal : 04/08/2020 1:08 am
jsw
 jsw
(@jsw)
Famed Member
RE: Filament 'pigtails/barrel roll' between spool and extruder as print runs

Update.

I just walked in to check the print, and saw a right-to-left X axis motion of 152mm (the width of the print) and I saw the moving filament push the outermost layer on the spool up to the point that it almost slipped off of the spool to the left.

I'm wondering if a couple of turns of filament were simply pushed off of the spool to the left that caused the twist in the filament.

Napsal : 04/08/2020 1:36 am
MileHigh3Der
(@milehigh3der)
Honorable Member
Topic starter answered:
RE: Filament 'pigtails/barrel roll' between spool and extruder as print runs

Do people manipluate their spools to ensure that they don't pick up a lot of friction and loops?  Is it more an issue with things like PLA?  I think I had a print fail because one of the loops kinked.

I have the MMU2s and I'm looking to do a system where I have all five spools in a drier that will run periodically to keep things dry.  So having to play with spools would be something I have to plan for.

I generally swap spools on and off every few prints or tasks as I make new things, so maybe this isn't an issue if you are taking spools out of service- but with an MMU, I'd like to keep them all active and run a whole spool with out ever touching it.  "Luckily" running an MMU isn't that seemless... so far.

Napsal : 04/08/2020 3:13 am
bobstro
(@bobstro)
Illustrious Member
RE: Filament 'pigtails/barrel roll' between spool and extruder as print runs
Posted by: @jsw

[...] I just walked in to check the print, and saw a right-to-left X axis motion of 152mm (the width of the print) and I saw the moving filament push the outermost layer on the spool up to the point that it almost slipped off of the spool to the left.

Thought I responded to this earlier... There's a design for a top-mount spool holder that orients the spool along the X axis instead of Y, with the idea that there is less side-to-side movement in that orientation, and fewer chances of snags. I'm working on a design for my Sidewinder based on that principle. My Mk3 spools are all underneath.

 

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Napsal : 04/08/2020 4:45 am
jsw
 jsw
(@jsw)
Famed Member
RE: Filament 'pigtails/barrel roll' between spool and extruder as print runs
Posted by: @milehigh3der

Do people manipluate their spools to ensure that they don't pick up a lot of friction and loops?  Is it more an issue with things like PLA?  I think I had a print fail because one of the loops kinked.

I have the MMU2s and I'm looking to do a system where I have all five spools in a drier that will run periodically to keep things dry.  So having to play with spools would be something I have to plan for.

I generally swap spools on and off every few prints or tasks as I make new things, so maybe this isn't an issue if you are taking spools out of service- but with an MMU, I'd like to keep them all active and run a whole spool with out ever touching it.  "Luckily" running an MMU isn't that seemless... so far.

A few comments here.

There's really no standard way people set up their spools, as each user has different needs.

Some use a very simple scheme.  A lady I know who has a printer like mine (without MMU2S) uses the stock spool holder and nothing else.  She puts the whole thing away in a closet when not in use and then puts it on the kitchen 'island' to print something.

Others have extremely elaborate multi-spool dryboxes with fittings for the filament to pass through, even through a wall from an adjoining room.

Mine is kind of inbetween.  I have the printer on a counter in the home office with a pipe rack of spools of filament that I use most hanging from some bookshelf brackets above the printer.  I have the MMU buffer mounted vertically right behind the printer.  On the shelf above I have a couple of those MMU spool holders for 1-2 rolls that are not on the spool rack for whatever reason.  If I use the MMU I'll load either of the above through the buffer and into the MMU, and unload everything when I'm done with the multi-material print.

For single filament printing I'll usually just feed the filament from the spool rack through a guide on the printer and into the extruder.  If it's a filament I don't use that often I'll get out the stock spool holder and use it, as I did earlier tonight, or put it on one of the spool holders on the shelf.  Right now I'm doing window assemblies for a model railroad building with black ABS frames and transparent (translucent) PETg for the panes, both of which I use semi-regularly and are more or less permanently racked up above.

For the filaments I use regularly, I really have not had to worry about them getting wet.  I typically use them up in several months at most and I have a humidity gauge in the office which at most reads in the low 30s.  I have not as of yet had any issues attributable to wet filament.

For the filaments I don't use regularly I have two dry boxes made out of Home Depot storage tubs, each with a cheap humidity gauge mounted on the side with a 3d printed bracket and four of those silica gel dry packs.  When the humidity in them starts to creep up I'll bake the dry packs in the oven for a few hours.  I try not to open the dry boxes unless I need to, as each opening lets more humid room air in.  I use one dry box mostly for full-size spools and the other for respooled tag ends and samples and the like.

I thought about permanently running a few filaments I use most into the MMU.  I gave up on that idea mostly because there are more than five that I use regularly and even with the buffer modifications, it's a pain to change them.  Also, despite my good luck so far with the MMU, it's a point of failure that seems to have a mean time between said failures far less than the Mk3S as a whole.  Just read the forum here.  🙂

That's the way I currently do it.  I'll probably adjust things off and on as needed.  Others have different needs and do things differently than I do.

Napsal : 04/08/2020 7:11 am
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