Functional metal parts were once the holy grail of additive manufacturing. Today, there are many processes available that can print metal, from SLS to direct powder metal deposition, to metal-infused flux materials that are then fired in a kiln. But the oldest additive metal technology dates back centuries: welding. Gefertec GmbH has taken the process of arc welding to its additive conclusion, building fully dense metal parts bead by bead.
Gefertec 3DMP is based on standard arc welding technology with wire feed stock. It’s possible to print parts up to 3 cubic meters (100 cu.ft.) in size, at a very high deposition rate. This allows bigger parts faster, at low cost. The builds are essentially near net-shape parts, which for many applications will require a machining step to finish the surface.
There are many advantages to this approach, including much higher deposition rates and a massive build envelope. The wire stock is also potentially more reliable than powder stock, which can be subject to impurities, moisture and other defects. Powder machines typically specify one machine per material to avoid contamination and powder metals can also pose safety risks to operators. With welding, the only hazards are arc radiation and fumes, both of which are handled by the machine.
Like most new technologies, the immediate question is, “What’s the trade-off?” For all the glory it gets for conformal cooling, internal geometry and rapid prototyping, additive manufacturing is not without its share of drawbacks, such as build time, part size, resolution, material strength and surface finish. No additive process tackles all of these problems at once.
For example, powder bed fusion tackles the build time problem by nesting parts and delivers relatively good surface finish. However, the parts are not isotropic, and it can be very expensive to fill a large chamber with powder. Gefertec’s 3D metal printing (3DMP) process tackles the problems of build time, strength and part size at the cost of surface finish and resolution. It’s important to choose a metal additive process that has strengths that align to your needs.
With Gerfertec’s 3DMP, it’s possible to create hollow structures, although they may look a bit different. There are examples of how channels and cavities look in the video above. The ability to make functional channels and voids is essential for tool and die making. The company is working a lot with tool manufacturers, making molds, dies and cutting tools.
In near net shape machining, such as with titanium, the process could cost as much as 60-70 percent less. That comes from cutting fewer chips, using less stock material and fewer cutting tools.
For more information about this technology, visit the Gefertec website.