If you are designing a geometrically complex part for a powder bed additive manufacturing process, you probably won’t need to design in supports as well, right? That’s sort of the accepted view when designing for 3D printing / additive manufacturing.
The more accurate answer is, it depends. In a recent webinar on 3D printing with metals, our guest speakers, Robert Chiari from Renishaw Inc., and Maximillion Eils from EOS, had some interesting things to say about supports.
The idea that many parts must have supports is “a bit of a misconception,” said Chiari. “When 3D printing started with plastics, supports were valid to keep part geometry from collapsing during the build process. It’s actually the opposite when you additively build parts with metals.”
For metal parts, the term “supports” has a different meaning. Support is more of a reference to the need for an anchor for the part. “Because of the stresses in the metals, and particularly in high stress materials like titanium, the material may pull away from the build sub-straight. So, the support is really a plate used to anchor the part during the build,” continued Chiari.
Noted Eils, with metal additive manufacturing, the powder surrounding the part as it’s being built performs another function—it helps remove heat from the part during the build. The lasers in some AM machines can send 400 W to 1 KW of heat into the powder build material. Heat must be controlled so as not to compromise part or material integrity. Thus, heat must be absorbed and sent down to the structures and directed to the platform.
Ideally, you want to minimize the amount of supports, whether they are vertical structures to ensure stability or flat but sizable build plates needed to produce any part. Sometimes material choice makes a difference. Often, the way a part is orientated in a build will reduce or eliminate the need for supports.
If you use a service bureau, the application engineers can offer tips and advise on how to do so with your specific design. Added Eils, in some cases you can achieve a 20 to 30% reduction in the support structures, saving material cost and time, while ensuring the part can be built.
Leslie Langnau
llangnau@wtwhmedia.com
