A FEM-based coupled thermo-mechanical model of laser-assisted machining of Ti6Al4V—a focus on chip morphology

Titanium alloys are vital in aerospace engineering due to their exceptional properties. However, the undesired formation of serrated chips during conventional machining poses challenges. Laser-assisted machining (LAM) offers a solution by improving chip morphology, yet optimizing LAM conditions is complex due to the multitude of process parameters involved. This research presents a novel 2D fully coupled thermo-mechanical finite element-based computational model for LAM of Ti6Al4V to effectively predict chip morphology and cutting forces. The model employs fracture mechanics principles to accurately simulate chip serrations, treating chip separation from the workpiece as mode-I failure and chip serrations as mode-II failure. The incorporation of laser heating physics employs the VDFLUX subroutine. Validation against experiments underscores the model’s accuracy in predicting cutting forces and characterizing diverse chip morphology under varying process conditions. Notably, the model identifies specific transition points from serrated to continuous chips, such as at 1000 W laser power, 20 mm laser-tool gap, and 3 mm laser spot size for a 90 m/min cutting speed. Similar transitions are observed at 800 W laser power for a 60 m/min cutting speed and a 0.2 mm/rev feed rate. Furthermore, the study comprehensively analyzes cutting forces, providing valuable insights into the LAM process. The developed computational model serves as a valuable tool for optimizing laser parameters to enhance chip morphology and improve the machinability of titanium alloys using LAM.