Sequential Post-Processing Methods to Enhance Surface Quality of Laser-Based Wire-DED Samples.

Abstract

This master's thesis investigates the feasibility of fabricating multi-material composite printing using a laser-based wire-DED printing technology. In the present study, stainless steel SS316L and mild steel ER70S-6 were printed separately as a monolithic sample and also top of one another to form a composite sample. The main objective was to investigate the interlayer connection or uniformity of both materials, followed by reducing the surface roughness using sequential post-processing methods. The interfacial investigation was done using a topological analysis by optical microscopy, followed by a microstructural investigation by SEM analysis and EDS analysis. The mechanical stability of the interfacial layer was evaluated using hardness testing. Furthermore, the surface roughness of the printed samples was reduced using sandblasting and centrifugal tumbling. The results showed that the interfacial layers were intermixed, exhibiting features of both grain structures. Also, the EDS analysis showed a sharp change in the elemental composition when traversing from SS316L to ER70S-6 material layers. The post-processing methods significantly reduced the surface roughness generated during printing, making it smoother and much more suitable for further use.