Residual Stress and Deformation of Consolidated Structure Obtained by Layered Manufacturing Process

Abstract

This study investigates the residual stress and deformation induced in a consolidated structure obtained through a layered manufacturing process. In this research, temperature and dynamic stress induced in the substrate during a selective laser melting (SLM) process were measured to investigate the influence of laser irradiation conditions on the development of residual stress and deformation in the consolidated structure. The stress was measured using a strain gauge that was attached on the bottom face of the substrate, whereas the temperature was measured using a thermocouple inserted in the substrate. The influences of the substrate height, consolidated structure height, and laser scanning pattern on the deformation and residual stress also were investigated experimentally. Additionally, the effects of different materials used as the substrate on deformation were investigated. It was found that during the laser consolidation process, temperature changes in the substrate caused repeated thermal expansion and shrinkage within the substrate, producing internal stress at the completion of the laser consolidation process. The stress that was induced in the substrate corresponds to the deformation result. Residual stress at the top of the consolidated structure increased whereas residual stress at the bottom of substrate decreased as the height of the consolidated structure increased. However, less deformation occurred when using stainless steel as the substrate.

Keywords

• layered manufacturing
• selective laser melting
• residual stress
• deformation
• carbon steel
• stainless steel