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Optimal Tension on the Filament?  

Trusted Member
Optimal Tension on the Filament?


I'm currently building a drybox to store my filament, including spool holders.

The first prototype of the holder allowed the spool to spin too easily. Already the tension of the filament on the spool itself caused the spool to unwind a little. Enough that the filament was loose and ended up next to the spool with would probably cause the filament to tangle up after a while.

So, a little friction that stops the spool from spinning freely seems to be necessary. If I add too much friction, the extruder will have to pull too strong on the filament and at some point the gears will just dig through the filament instead of moving it. I guess also before that the print quality will suffer.

What I would like to know: How much tension on the filament is adequate? Certainly I don't want to go to the max, but I do want to know that / if the tension I use is much below the value that would cause problems of any kind. Also, I guess this is different for different materials. Flex will probably show problems earlier than PETG...

Do you have experience at which tension problems start?

Best regards


Posted : 21/10/2020 11:46 am
Peter M
Noble Member
RE: Optimal Tension on the Filament?

If you search on the prusa website for print models, you can find spools to print that will also go backwards, if there is to much filament it will roll backwards.

Search for this.

1 model the spool will go up a hill, and if there is to much filament it will go backwards, and there is 1 model with a spring in it.

Posted : 24/10/2020 9:11 pm