File under "half-baked ideas".  I love 3d printing (and I don't even have a

File under “half-baked ideas”. I love 3d printing (and I don’t even have a 3d printer yet, although I have ordered a QU-BD RPM!). The one MAJOR feature lacking in current FFF printing technology (IMHO) is ability to create prints that are “durable”. When I say “durable” I mean - have strength and toughness akin to metals. I’ve spent a lot of spare thought cycles trying to think of a way to add “toughness” (strength) to 3d prints, and I had the following idea.

You can buy chopped carbon fiber (see link below). What if one were to create filament with the chopped carbon fiber mixed in? Then, when you print, assuming the filament still maintained usable melting/flow characteristics, your print would have chopped carbon fibers embedded throughout - creating a carbon fiber composite print. True, it wouldn’t be as good as woven carbon fiber cloth strengthwise, but it seems like it would make the print stronger (but perhaps not any more resistance to abrasion)…?

Thoughts? It’s just an idea (coming from someone who has never used a 3d printer before) so please be gentle if you think it’s stupid… :wink:

Similar thoughts have crossed my mind but I see many problems with fibers in the filament.

The nozzle is quite small compared to injection molding machines and might tend to clog. Perhaps a laminar flow hot end would help prevent clogging.

Stringing might be more of an issue.

There would also be the problem that all of the fibers would be in the X-Y plane of the build with none in the Z direction, making the bond between the slices weak.

@Wylie_Hilliard - perhaps a larger diameter nozzle would help as far as the clogging issue (of course, that will have effects on detail, but I’m interested in making mechanical parts, not artistic parts).

Also, I am wondering if perhaps when the layers are hot and bonding to each other, perhaps some of the fibers would “blend” in the interface between the layers? Dunno… just a thought…

Nylon is amazingly durable, though it’s more flexible than steel. And it’s pretty easy to print.

The weakest point in prints is the inter-layer adhesion, and fibers mixed into the plastic would not cross layers, so they would not have a significant effect on strength.

BTW, nylon has the best inter-layer adhesion of any material I’ve tried.

Good point. Taulman 645 Nylon I have printed 0.4mm layers (!) and they’re impossible to pull apart. Amazing stuff.

Hmmm. So the fibers wouldn’t help the z-direction strength but if the loads on the part are in the x/y plane…

for X/Y plane strength, maybe, but any fibers long enough to not clog the nozzle are unlikely to have a measurable effect.

I want to try nylon so bad… I might order some in a few months.