An interesting and more in depth look at the output from this machine. It does look as if they are getting some serious strength boosts.
http://techcrunch.com/2015/01/12/markforged-shows-us-3d-printed-parts-that-even-fezzik-couldnt-break/
http://techcrunch.com/2015/01/12/markforged-shows-us-3d-printed-parts-that-even-fezzik-couldnt-break
I was curious if anyone had seen this thing in the wild yet. Thanks for the post!
Awesome. I’m very interested in the future prospects with pure carbon fiber printing. Also what nozzle tech they’re using 
They claim its the only printer that prints carbon fiber!.. They’re either lying or really really terrible at using Google.
Pure carbon fiber ribbon. The protopasta stuff is chopped up
You can only make them so long… And there has been another company to demo long strand carbon filament.
@Matthew_Satterlee , most 3D printers that can do carbon fibre are actually doing small fibres of carbon fibre suspended in a polymer the printer can handle, much like the wood, stone and bronze filaments you might have seen. The shredded carbon fibre adds a bit more tensile strength and shear strength to the parts, but they aren’t as strong as pure carbon fibre.
guess the hardest part is getting the layers to fuse so the cabon strands between the layers are mixed. Being able to extrude a carbon/resin mix as a thick paste mix would be nice with some kind of delayed or UV curing.
Folks have been saying that continous cf strands will not increase interlayer strength and technically they are right. If you set up a test jig and pull exactly vertical you won’t notice much difference. However most stresses a part might experience won’t be of this sort. A lot of printed parts delaminate when you bend them across the grain. The extruded lines bend and cause a shear between the layers and they fail. For example taller ABS parts fail at the layer interfaces due to their own shrinkage strains. But because these parts won’t stretch much along the grain the shear won’t have a chance to develop so the layers won’t delaminate as readily as a non-reinforced layer. Make sense? I loved the idea immediately then thought hey wait! But then fell in love again 
ABS can be strengthened significantly by acetone vapor smoothing and PLA can be annealed (somewhat) in an oven.
Seen it in the wild a couple of times, their new software is very nice all in Chrome it automatically generates the optimum position of the fiber but, say you decide that your part requires only a little fiber adding to one zone you can go back and adjust. Spoke to Greg Mark at CES and his background is interesting in that he came to the idea through necessity rather than inventing a tech and hoping for an application. Here’s a little video we did with him > http://mytct.co/MarkForgedCES2015