The Hackaday Tip Line has been ringing with submissions about the Mark Forg3D printer, purportedly the, “world’s first 3D printer that can print carbon fiber.”
Right off the bat, we’re going to call that claim a baldfaced lie. Here’s a Kickstarter from a few months ago that put carbon fiber in PLA filament, making every desktop 3D printer one that can print in carbon fiber.
But perhaps there’s something more here. The Mark Forged site gives little in the way of technical details, but from what we can gather from their promo video, here’s what we have: it’s a very impressive-looking aluminum chassis with a build area of 12″x6.25″x6.25″. There are dual extruders, with (I think) one dedicated to PLA and Nylon, and another to the carbon and fiberglass filaments. Layer height is 0.1mm for the PLA and Nylon, 0.2mm for the composites. Connectivity is through Wifi, USB, or an SD card, with a “cloud based” control interface. Here are the full specs, but you’re not going to get much more than the previous few sentences.
Oh, wait, it’s going to be priced at around $5000, which is, “affordable enough for average consumers to afford.” Try to contain your laughter as you click the ‘read more’ link.
That’s all we know. There’s no mention of how carbon fiber get into the printed objects. Is it embedded in a plastic filament, like the previously mentioned filament, or something far more exotic? If the former, the idea of printing with carbon fiber doesn’t make sense except in a very few niche cases.
I’ll be one of the last people on earth to claim experience in composite fabrication, but I have built a few things with resin and cloth, and know a little bit about why 3D printed carbon fiber parts is a really dumb idea. With composites like CF, fiberglass, and Kevlar, all the strength is derived from the bias, or the direction of the weave. If you want to make a part strong in one direction, lay your cloth down at an angle and slather on some epoxy. Need it stronger in two directions? You need two layers of cloth, at least.
This is rudimentary stuff, and doesn’t even touch on vacuum bagging, and degassing the resin. There’s a whole host of other things that make carbon fiber crazy strong, and you just can’t do these things by hitting a ‘print’ button.
That being said, there are probably less than a dozen people on the planet that know how this printer actually works. Is there some magic in the way Mark Forge filament is produced? Are there special slicing algorithms that capitalize on the unidirectional strength of CF? Is this just a tool for printing things with carbon fiber for the sake of printing things out of carbon fiber? I don’t know.
If you have any information on how this printer actually works, post it in the comments. If you have any materials testing data on a part manufactured on a Mark Forged printer, post it. We’re dying to know if this is actually a cool product, or just a cool business model and a bit of PR.