Filament gets tangled during printing (all the time)  

RE: Filament gets tangled during printing (all the time)

Which printer and what extruder and hotend?  

I have never heard of or seen this problem, but more information on your setup might help.

RE: Filament gets tangled during printing (all the time)

I'm using the ORIGINAL PRUSA I3 MK3S+. All default, printing the Prusament PLA.

RE: Filament gets tangled during printing (all the time)

Pictures would be helpful too. I have a hard time picturing what you described.

RE: Filament gets tangled during printing (all the time)

I would suggest that you use a 'reverse bowden' setup, to reduce the interaction between the extruder position, and the filament roll position

regards Joan

a few ideas below

https://www.thingiverse.com/thing:3555889

https://www.thingiverse.com/thing:4847168

https://www.thingiverse.com/thing:4520193

https://www.thingiverse.com/thing:4119274

https://www.thingiverse.com/thing:3748479

RE: Filament gets tangled during printing (all the time)

Posted by: @happycerberus

I have observed it enough times to understand what is happening now.

1. The filament gets loose by the printing head pulling it to the side and then coming back.
2. When loose, the top filament loop is pushed beneath one of the later layers by the sideways motion of the head.
3. As the filament is getting pulled, it gets taught before it naturally untangles itself creating a loop (not an actual loop, just crossing layers).

Does anyone have a fix for this? It's extremely anoying.

I have seen this happen with very badly wound spools. When Amazon switched from Overture to some other brand for their AmazonBasics house brand, I received 2 spools that were loose enough to snag in this manner. Every other spool has been reasonably wound and, if cared for, will not snag due to simple side-to-side extruder motion.

Are you using the Prusa top-mounted filament spool holder? Be very careful to keep the end of the filament under control at all times. Either feed the end of the filament into holes provided on the spool itself, or use a clip of some sort. I use the smallest size binder clips for this. Do NOT let the end loose at any time. Filament doesn't need to be perfectly wound on the spool, but it shouldn't be loose to the point that strands can slip under each other as it's pulled.

Send us a pic of your filament stand and spool and we may have more suggestions.

RE: Filament gets tangled during printing (all the time)

I guess now I understand what the issue is. As Bob said, some brands (such as Prusament) are great at winding the filament perfectly, others...not so much. It's particularly important on unloading to keep some tension on the spool, to keep the filament wound nicely. 

You may also want to consider using a filament guide mounted in the middle of the x axis, which helps reduce the movements to the left and right. The way I have my spools mounted on top of the enclosures doesn't make that necessary for me but I have used guides before. Just do a search for filament guides on Prusa printers.org. There are quite a few for the Mk3S. 

RE: Filament gets tangled during printing (all the time)

This has happened to me several times and I use a filament guide and only use filament I buy from the Prusa shop. I mostly avoid it by rolling the spool forward a few times so that there are several loops with plenty of slack. When I check on how my print is going, I also check the slack on the spool.