I know a lot of people here talk about ensuring their filament doesn't absorb

3D Printing
, , ,
1

I know a lot of people here talk about ensuring their filament doesn’t absorb too much moisture. A lot of you keep your spools in Tupperware bins with bags of desiccant, etc… I’m having the exact opposite problem. My filament becomes EXTREMELY brittle. Trying to feed my extruder, the filament will snap and I have to pull about a half meter from my bowden tube which becomes a huge waste. Anyone else have this problem of ‘too dry’ plastic. How did you solve it? This becomes extremely frustrating!

Thanks in advance,

2

it is not “too dry”, it is not pasta, if it is brittle it is probably just old and for PLA probably more crystalized internal structure… or damaged by UV… or even damaged by moisture, hard to say…

3

As stated above, it’s probably old. I had a spool that started breaking and I just pitched it. I did notice though that it was bubbling as well when I was printing which lead me to believe that it had moisture in it as well. If it’s like 6 months old or has been sitting in the sun, it’s probably time to just pitch it.

4

It’s too wet. Dry it out at 90C in an oven for about an hour. Let it cool down with the oven closed for 2 hours.

Should be supple afterwards

5

PLA filament brittleness is caused by the crystallinity changing slowly as it ages. There’s a TON of stress locked into PLA filament at manufacture because it’s stretched down to the correct diameter and then rapidly cooled in a water bath… locks a ton of stress in the molecular arrangement. That stress makes the molecules slowly creep apart over time, and it gets progressively weaker. (Similar thing happens to printed PLA left under sustained high stress for a long time – it eventually creep-cracks.) It’s just a crappy thing PLA does.

Heating it in an oven or whatever will basically anneal out the residual stress and aged crystallinity and get it to a tougher state. That’s not a moisture thing, it’s polymer voodoo. The problem is, you can throw off the filament dimensions and end up with oval, off-spec junk that you have to throw away. So I’d recommend trying half a day at ~50C rather than an hour at 90C or whatever.

6

Good advice here. Yes. It is voodoo.

7

Good info @Ryan_Carlyle , I can vouch for the aged filament being extremely brittle. When I’d picked up some old printers on the cheap, they still had some 3mm PLA spools and you couldn’t even pick up a piece of filament without it breaking apart.