Carbon fiber reinforced plastics

Hi Everyone
Maybe some of you know, carbon fiber filled SLS is availible, the problem is that because it is in powder form the strands of fiber are pretty short=not giving much structural strength.

When using the FDM/FFF/hot melt techonogies the product is made from a long continous strand, if one could embed carbon fiber in the filament one would end up with a product comparable to real carbon fiber. (or at least so i assume)
This again would open up for whole new potentials of having a printed high strength product.

Anyone heard of this to be possible, anyone any idead on how to get filament filled with carbon fiber filling?

Best regards

I'd imagine retracting and moving without extruding might be a problem, the fibres would drag things around if they were too long and not give much added strength if too short. Perhaps an addon fibre shear at the nozzle to chop things off cleanly?

Cheers,
Robin.

... an interesting alternative could be Selective-Wire-Printing - here you push a plastic wire (maybe with CF reinforcement) through a thin nozzle, so the tip touches the surface, then melt the tip with a laser and move the nozzle with feeding and melting the wire synchronously in XY as with the FDM head.

The structural strength will be much higher than with other methodes ...

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Viktor
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Just found this

[investors.stratasys.com]

Stratasys are developing carbon fiber reinforced feedstock for profesional FDM machines.

Maybee a modified filabot could embed carbon fiber thread into a plastic filament, I am thinking of trying some experiments using fishermans carbon fiber thread (the sort they use for tying flies) possibly feeding the carbon thread directly into the hotend of a reprap extruder and rigging up some sort of mechanical "cigar style" cutter to cut when the extruder filament retraction command kicks in.

This way I may be able to get it working without the need for extensive firmware reworking.

Anyone else experimenting with directly printing carbon fiber?

Graham

They are probably mixing a mass of short, thin carbon fiber filaments into the plastic, so that it can be just extruded normally. Trying to embed a one continuous line of carbon fiber into the extruded track would probably be extremely tricky. But in any case the carbon fiber wouldn't reinforce the inter-layer and inter-track joins, which are the weakest link even now. So I wonder whether it would improve the final strength of the object that much.