Deformation and control method of thin-walled part during laser powder bed fusion of Ti-6Al-4V alloy

The large thermal stress caused by the high temperature gradient leads to part deformations which are the important factor restricting the rapid development and wide application of the laser powder bed fusion (LPBF) technology. In the present study, a layer-by-layer model based on the finite element method was developed to study the thin-walled part deformation and the effect caused by the part dimension during LPBF of Ti-6Al-4V alloy. The deformation along the length direction dominated for the thin-walled parts, and the maximum deformation occurred at the middle of the thin-walled part. A mechanism built in the present study revealed the deformation evolution of the thin-walled part. With the increase of the part height and length, the maximum deformation increased first and then tended to be stable. However, the maximum deformation decreased with an increase of the part thickness. Furthermore, a method of compensation design was used to effectively reduce the deformation of the thin-walled part. The simulated results and the deformation control method were validated by the experimental data. The investigated results of this research provide a significant understanding of the part deformation during the LPBF process.