Metal X. It sounds like the name of everyone's favorite X-Men character, but it's actually the latest in a string of 3D printers debuted by carbon fiber pioneer Markforged.
At CES 2017, the start-up most known for introducing carbon fiber reinforcement to the 3D printing industry broke new ground once again with a 3D printer capable of 3D printing metal parts at a low cost.ENGINEERING.com spoke with Greg Mark, CEO of Markforged to learn more.
Atomic Diffusion Additive Manufacturing
Mark explained that the Metal X 3D prints with a process similar to atomic diffusion bonding, resulting in what Markforged refers to as atomic diffusion additive manufacturing (ADAM). ADAM involves 3D printing with bound-powder rods, in which metal powder is contained within a plastic binder. A cartridge of these rods feeds the material to the printer, which prints the object layer by layer, melting the plastic and fusing it to the preceding layer.
Once the process is complete, the part can be placed in a traditional sintering furnace, which burns away the plastic and brings the metal to within 85 percent of its melting temperature. The metal fuses together, the component shrinks by about 20 percent, as is expected, and what's left is a nearly fully dense metal part.
“Basically, we looked at the way our continuous fiber works,” Mark said, explaining the nature of the ADAM process. “Our continuous fiber is continuous strands of carbon fiber wrapped in a plastic. Then you basically remelt that plastic when you’re printing it. So, we did the same thing with metal. We have a metal powder—which is by itself toxic and flammable—we infiltrated it with plastic, which makes it safe to breathe, safe to handle and nonflammable.”
This is unlike powder bed fusion processes that fuse metal powders with a high powered laser or electron beam. The metal powders are often volatile and must be handled in a specialty vacuum chamber. Not only is the material used with the Mark X meant to be safe to handle, but the ADAM process offers design and production advantages that powder bed processes don’t have.
Because the ADAM process uses a binder that can be burned away, it's possible to print closed objects with complex internal geometries, such as hexagon infill patterns, which can significantly lighten the weight of a part while maintaining structural integrity. It's also possible to 3D print moving assemblies. In this way, the Metal X is not unlike XJet'sNanoParticle Jetting (NPJ) system, which was unveiled in 2016. NPJ also involves a binder that is burned away during the sintering process.
Parts printed with the Metal X can be post-processed the way any traditional metal part can, once it has been sintered. Mark explained that parts can be post-processed, due to the softness of the binder, they can even be lightly wetsanded before sintering and, once they come out of the oven, they will maintain a smooth finish.
Metal X Applications
The Metal X 3D printer is described by Markforged as the first metal 3D printer priced under $100,000. This may be true, as most metal 3D printers are well above that price point. The layer resolution of the system, 50 microns, is comparable to most powder bed fusion metal 3D printers. Parts are between 95 and 99 percent dense, depending on the furnace used to sinter the parts, making it competitive with direct metal laser sintering systems.
According to Mark, the system is already capable of 3D printing with 17-4 and 303 stainless steel. The company has stated that other metals are already under development, including A-2, D-2 and M-2 tooling steel for injection molding, as well as 6061 and 7075 Aluminum and 6AL 4V Titanium.
Mark believes that the tooling steel will allow for the “killer app” of the Metal X. On why Markforged chose a consumer trade show to launch an industrial 3D printer, Mark said, “At this show, everything you see is injection molded plastic. Everything you see is made on the most beautiful injection molding machine in the world. The mold takes like two to four months to make and slows your life down. The Metal X can print that mold in about a day and a half.” He added, “You can take a 20-year-old injection mold, you can put a beautiful 3D-printed insert into it and you can retool it in under a week.”
Specs of the Metal X
The Metal X has a similar frame to the machine's carbon fiber printing predecessor, the $69,000 Mark X industrial carbon fiber 3D printer. It has a substantial build volume of 250mm x 220mm x 200mm (9.8 in x 8.7 in x 7.9 in), includes a built-in camera and runs on the Markforged cloud-based Eiger software platform.
The Metal X 3D printer. (Image courtesy of Markforged.)
Shipping for the new system begins in September with the aforementioned stainless steel capabilities, but Mark said that other materials would likely be made available pretty shortly after that. The price of the Metal X starts at $99,500, which does not include the necessary furnace, but, according to Mark, many of the firm’s clients likely already have one.
Interestingly, all of the Markforged systems are available as upgradable packages. While the Onyx One, capable of 3D printing chopped carbon fiber filament, is available for $3,499, it can be upgraded to 3D print with fiberglass reinforcement for another $3,499. It can be further upgraded to the Mark Two or Mark X to print with continuous carbon fiber. And, if you've fallen in love with all of the above and have the dough, it's possible to purchase the Mark X and Metal X in a bundle $149,000.
To learn more about the Metal X, visit the Markforged website.