TGA of Filament

[printedsolid 3]

Hello, I've posted this over at the makerbot forum and am reposting here. I have access to a TGA (thermogravimetric analyzer) at work. I'd like to start evaluating filament to analytically determine absorbed moisture content and recommended bake out/storage conditions.

I ran some Taulman 618 today that someone said they were having trouble with. After about two hours at 93C/200F, it had lost about 1.5-2% of its mass due to moisture being baked out. It still hadn't entirely stabilized, but the rate of loss of mass had slowed considerably.

Honestly, I'm not entirely sure where this is going, but it never hurts to learn a little more about your materials.

Does anyone have any filament that you suspect is causing you trouble due to moisture content? I'd be interested in testing it for you. I only need about 10mm of length to get the test. I'm curious how different materials, brands, and colors will compare.

PM me if interested or email to mgorton at printedsolid dot com and I'll send you my address.

 

[matengi 0]

Polyamides absorbes a consideral amount of water, depending on the type, because of the hydrogen bonds of the molecules. For PA 6.6, 2.5-3% are usual. Polyamide parts coming out of a injection molding machine are rather brittle. Often a water container is placed below the machine. After some hours of waters the parts are as flexible as PA usually appears.

Heated and dried PA filament will therefore again absorb water from the environment and end up as heavy as before. However the heat treatment may reduce bubbles and vapor coming out of the nozzle during printing, best is to dry the filament just before usage.

 

[jumpmobile 0]

Jep, this is also what I think is what happening with ABS.

I bought one role of whit ABS and the first few prints where really beatiful, but after a few days things went bad. The surface of the prints got small -almost unvisible- imperfections and when I tried extruding in the air the string that came out had bends in it and also one small bubble.

I really think that moisture in our filaments is causing us trouble. You can observe that this experience is made alot since there are many entries on groups and forums that start with " I bought a printer and the first few days/week it was really nice but now my prints don't look as well as before. What can I do?"

How about a "dry chamber"? A box with silica-gel where one could store the filament without letting it absorb moisture.

Fabian

1st Edit:

Found this enlightening video on the use of silica-gel in a dry chamber:

 

2nd Edit:

And a promising, low cost approach that also solves the dust buildup problem:

http://www.thingiverse.com/thing:62826/#comments