Thermography for monitoring the selective laser melting process

A lot of strategies exist to monitor and control additive layer manufacturing processes. Basically one can distinguish between coaxially monitoring the process zone and monitoring the complete layer currently being built. Since Selective Laser Melting is a thermal process, a lot of information about the process and in consequence about the resulting part quality can be gathered by monitoring the temperature distribution of a complete layer and its temporal evolution. It depends on the geometrical configuration of parts being built and the quality of the powder layer deposition. In this paper, process errors originating from insufficient heat dissipation are investigated as well as the limits for detecting pores and other irregularities by observation of the temperature distribution.