The effects of polymeric binder on microstructural characteristics of powder sheet additive manufacturing

A novel laser-based additive manufacturing approach of metal additive manufacturing using powder sheets (MAPS) has been introduced recently. The method utilizes polymer-bound powder sheets for metal AM as a feedstock, instead of loose powders. Conventional laser beam powder bed fusion (LPBF) additive manufacturing (AM) is among the most widespread 3D printing technologies. However, LPBF faces challenges related to safety and the impracticality of changing materials due to its reliance on loose powders. Thus, MAPS demonstrates the capability to overcome the limitations of LPBF by offering enhanced safety and the ability to print multi-material structures without the risk of material cross-contamination. As a part of developing processes, we investigate the effects of polymeric binder content on the printability and microstructural characteristics of MAPS-printed stainless steel 316L. The results indicate that the average layer thickness of solidified material improves as the scanning speed decreases from 1000 mm/s to 50 mm/s across three different polymeric binder contents: 10 wt%, 20 wt%, and 30 wt% PCL. Additionally, a higher polymeric binder content in the powder sheets reduces the likelihood of crack formation. Electron backscatter diffraction (EBSD) analysis reveals that an increase in scanning speed promotes the formation of more equiaxed grains, while an increase in polymer content results in a reduction in grain size. These findings provide valuable insights into optimizing MAPS configurations for enhanced productivity and functionality in metal component manufacturing.