Individual process development of single and multi-material laser melting in novel modular laser powder bed fusion system

Abstract

Additive manufacturing and especially the laser-based powder bed fusion (LPBF) with full melting of the powder offers tremendous potential and versatility for manufacturing high quality, complex, precision metal parts. However, for novel powder compositions the LPBF process development is very time consuming and cost intensive due to the layer wise melting and the powder prices. This research work investigates the manufacturing of single and layered multi-material structures in a novel modular lab-scaled LPBF machining system through individual process and material development. The developed system allows the use of different laser sources, optical arrangements, individual sensor and actuator integration. In addition, the modular LPBF system enables the manufacturing of specimens with a minimum amount of powder, individual mixed powder compositions or layered multi-material parts. In an application example, a multi-material specimen made out of stainless steel 316L and Bronze 90/10 was manufactured in alternating layers. For this approach, a parameter study was performed for each material to investigate the influence of the volumetric energy density (VED) on the specimen density, surface flatness and reduced mixing zone formation. Afterwards, optimized parameters were used to demonstrate the feasibility of the system to produce a multi-material layered 316L-Bronze part.