Product Code: ICA11_404

Correlation Between Pyrometer Monitoring and Active Illumination Imaging of Laser Assisted Additive Manufacturing of Stainless Steel
Authors:
Antti Lehti, Lappeenranta University of Technology; Lappeenranta Finland
Lauri Taimisto, Lappeenranta University of Technology; Lappeenranta Finland
Heidi Piili, Lappeenranta University of Technology; Lappeenranta Finland
Olli Nyrhilä, EOS Finland; Turku Finland
Antti Salminen, Lappeenranta University of Technology, Machine Technology Centre Turku Ltd.; Lappeenranta Finland
Presented at ICALEO 2011

Laser assisted additive manufacturing of stainless steel is a method for manufacturing 3D parts from stainless steel powder layer-by-layer by assist of laser beam. Stainless steel is molten directly by laser beam and solidified layers of material forms desired 3D structure. Nowadays range of materials that can be used for laser assisted additive manufacturing is widened and high automation level of equipments has made this method more interesting process for rapid manufacturing. This is why also methods to control the process have started to gain an essential role in laser assisted additive manufacturing processes. Control of process parameters is also essential to get good appearance, good quality and good strength properties of workpiece and still maintaining the optimum processing speed. Control of temperature in laser assisted additive manufacturing is most important of all numerous process factors. The objective of this study was to monitor laser assisted additive manufacturing process simultaneously with pyrometer and video camera system with active illumination. Aim of this study was also to find out correlation between phenomena captured with imaging system and pyrometer measurement data. The laser system used for tests consisted of IPG 200W CW fiber laser and the procedure was executed in inert atmosphere. The material used was EOS stainless steel powder. Process was examined with fixed monitoring devices pyrometer and video imaging system with active illumination and the obtained results were collected for afterwards analyzes. Results indicate that several phenomena observed from video imaging system had correlation to phenomena noticed during pyrometer measurement. This makes pyrometer monitoring suitable method for controlling laser sintering process