Investigation of effects of printing patterns on geometry and densification of stainless steel 316L through directed energy deposition

Abstract

Directed energy deposition (DED) is an additive manufacturing process where metal wire or powder is added onto an object or substrate through melting of the filler material. Unlike the selective laser melting (SLM) process, where powder is applied onto a bed before laser melting occurs, DED melts the powder midstream. The molten particles are deposited into the melt pool which rapidly cools due to the laser traversing away. To build a part, the laser will overlap different layers with same stepover and printing patterns. However due to the nature of the printing patterns the time taken to print is usually different which results in non-uniformity in formation of structures. This experiment investigates the effects of powder flow rate, feedback loop system, laser power, and print patterns on the geometry and densification of SS316L powder.