Numerical prediction of residual stress and distortion for laser powder bed fusion (LPBF) AM process of Ti-6Al-4V

The demand of additive manufacturing (AM) processes has increased in the industry due to its realistic printing of complex geometry parts. The process involves with continuous melting of powder and rapid solidification. The heating and cooling attributes to the formation of residual stress which leads to the distortion in the AM part. The prediction of distortion and residual stress before printing could minimize the rejection of parts due to dimensional variation. In the present research work, an attempt was made to simulate LPBF AM process using MSC Simufact software for Ti-6Al-4V material. The simulation results are compared with the existing literature. The simulation parameters are optimized to minimize the deviation between experimental and simulation results. The inherent strain value, voxel size and other simulation parameters are utilized to predict the distortion and residual stress of a micro-tensile specimen. The distortion and residual are predicted in different orientations (0°, 30°, 45°, 60° and 90°) and at position of the base plate. It is observed that voxel size (accumulation of physical layers) has a significant effect on the prediction accuracy. The specimen placed near the power collector bin and gas inlet side shows minimum residual stress. The residual stress in the gauge section of 45° orientation is minimal compared to other-oriented specimens. The limited distortion is noticed for the 0° orientation specimen as the height of the sample is minimal.