Part re-registration during process interruption of electron beam melting additive manufacturing

Abstract

Advanced additive manufacturing (AM) technology for the creation of parts with enhanced or multi-functionality is emerging through developments in component embedding and multi-material fabrication techniques. With the current state of the technology, the embedding or multi-material fabrication processes generally require AM process interruption and part removal, referred to here as stop and go fabrication. Part position error is introduced during repositioning of the part before fabrication is resumed. An additional challenge when using electron beam melting (EBM) technology for stop and go fabrication is an environment that makes it difficult to use standard measuring tools to achieve proper part registration due to ultra-high vacuum at up to 10−4 Torr and high processing temperature exceeding 800 °C, thus limiting access to the build chamber. In this work, a part positioning technique based on the analysis of infrared (IR) images was developed as a viable contactless and real-time option to reduce registration error for EBM stop and go fabrication. This work introduces stop and go fabrication for a cylindrical part and a rectangular prism that were fabricated using EBM with part repositioning using the IR imaging technique. Following fabrication, the linear and angular displacements of the parts were measured and the absolute maximum misalignment values of 0.17 and 0.87 mm were obtained for the cylindrical part and the rectangular prism, respectively. These results suggest that this simple image analysis-based part positioning technique can be employed in advanced AM fabrication, including multi-material fabrication, sensor embedding, and repair applications.