Selective Laser Melting SLM
The ProcessFraunhofer ILT, Aachen / Volker Lannert.
The default material used in the SLM process is a metal powder. Inside a closed process chamber, powder is applied to a substrate plate as a thin layer with a hight of approximately 30 - 50 μm. According to the layers of the sliced CAD model, the powder is selectively melted by the local application of heat from a laser beam. Afterwards, the substrate plate is lowered and a new powder layer is applied. The next layer is again melted selectively with laser radiation and binds metallurgically with the lower layer. This way, the tailor-made part is generated layer by layer from the powder material. As a result of complete melting of the powder particles the build part can reach a relative density of approximately 100 percent.
Commercially available powder materials for the SLM process include stainless steel, tool steel, titanium-, aluminum-, cobalt- and nickel alloys. Due to these reffered characteristics, the mechanical properties of SLM components correspond to the specifications of the material used to a great extent. The completed component is given a final processing and heat treatment according to its envisioned application, in order to reach the required surface quality and dimensional accuracy as well as the desired microstructure with the corresponding mechanical properties.