Metal additively manufactured components: Challenges and solutions in the post-processing process
Metal additive manufactured (AM) components are essentially "welded" to the build plate, which means that the components cannot be easily removed. Even after removal, they require post-processing before they are ready for use. The following highlights some of the cost points and key processes involved in post-processing AM components, in particular the essential heat treatment process.
Stress relief
The layer-by-layer forming of the parts causes internal stresses due to the heating and cooling of the metal. These stresses must be removed before the part can be released from the build plate; otherwise the parts may warp or even break. To reduce the pressure on the components, you need a sufficiently large oven or furnace (preferably with environmental control) that is large enough to hold the entire panel. Many experts recommend using an oven in an inert environment to minimize oxidation on the surface of the parts. Others prefer vacuum furnaces, but they are significantly more expensive ($100,000 versus $10,000 to $30,000).
Heat treatment process for metal 3D printed parts
Cooperation with customers and several universities has shown that vacuum processes are advantageous:
- Minimization of surface contamination at high processing temperatures, which leads to an improved mechanical reaction of the components.
- Increased repeatability in mechanical and corrosion resistance tests of various printed components.
- Cleaning and shine of the surface in some cases, even if the atmosphere is controlled but not completely oxygen-free.
These advantages are particularly important in aerospace and medical applications, where strict regulations must be adhered to in order to reduce surface contamination and maximize mechanical properties.
To summarize, vacuum heat treatment is an essential step in post-processing, especially for specific components and materials that are processed using SLM technology.