Control of selective laser melting processes: existing efforts, challenges, and future opportunities

Additive Manufacturing (AM) or widely known as 3D printing is a technology for producing parts directly from the computer without the need for traditional tools. The technology provides fast production for complex shapes with higher properties. Selective Laser Melting (SLM) is one of AM technologies that is used to produce metallic parts. For the last twenty years, the technique attracted the attention of both industry and academia. The complexity of the underlying physics and the fast dynamics during the process degraded the quality of the produced parts and hampered widespread adoption of the technology. A significant emphasis on the importance of on-line control systems to achieve higher levels of quality and repeatability can be found in the literature. In this review paper, we fill an important gap in the literature represented by the absence of one single source that describes what has been accomplished and gives an insight into what still needs to be achieved in the field of process control for metal-based AM processes. The article ends by discussing future opportunities in the associated on-line control system development.