Densification of iSLS surface layers by means of shot peening

Indirect Selective Laser Sintering (iSLS) has a disruptive potential for meeting the requirements of transmission components for electromobility such as gears. Some of these requirements deal with lower levels of noise, vibration and harshness. Manufacturing by iSLS enables new solutions to these demands, mainly due to its higher printing speeds compared to other additive manufacturing (AM) techniques. A combination of reduced laser power, high scanning speeds, larger layers and lower melting temperatures of the polymer matrix are employed to this end. However, there are still challenges regarding the low densities resulting from the intrinsic characteristics of polymer-coated metal powder. Shot peening (SP) is a process with the potential to densify surfaces due to the transformation of kinetic energy into deformation energy. The implications of iSLS usage are still seldom covered in the literature. This study aimed to explore the influences of surface layer densification by SP using different peening parameters such as media diameter and coverage.. The density of the material, the percentage of densification in relation to depth and the residual stresses were evaluated. In the light of the functional requirements of high performance components, the results provide information on the density reached by iSLS processing and on the densification percentage as a function of depth.