The Response Surface Methodology for Optimizing the Process Parameters of Selective Laser Melting

Additive Manufacturing and Selective Laser Melting in particular have emerged for a few years as an outstanding alternative to conventional manufacturing for low production of highly complex and/or customized products and parts. The potential for production of very high density parts with excellent mechanical properties however necessitates thorough optimization of the process and its numerous parameters. A method for optimization adapted from the Response Surface Methodology seems the most appropriate. It consists in varying the process parameters according to an experimental design and record a response characteristic of the quality of the product. To illustrate this approach, a CoCr-Mo alloy has been produced by Selective Laser Melting with different combination of scanning speed and laser power, and the porosity and hardness of the as-built materials were measured and compared. This allowed determining a suitable processing window for such alloy. The possibility to produce high density parts (porosity 0.1%) is demonstrated and highlights the value of the optimization method.