3D coupled thermo-mechanical simulation of surface roughness and residual stress in end milling aluminum alloy

Surface roughness and residual stress are related to the fatigue life of finished parts. However, experimental investigations lack a deep discussion about the cutting mechanism. Orthogonal cutting simulation for milling or two-dimensional finite element model is the simplification of the actual milling process, which makes it difficult to reflect the milling characteristic in the simulation. In the present study, a three-dimensional coupled thermo-mechanical simulation model was established to analyze the surface roughness and residual stress in milling 5083 aluminum alloy. Explicit dynamic analysis was used as the solution algorithm for the milling process. Implicit analysis was adopted to simulate the process of unloading and cooling. Mesh sensitivity analysis was conducted to identify the mesh size of the workpiece. Node displacement and stress information were output to calculate the surface roughness and residual stress. The effects of cutting parameters on surface roughness and residual stress were discussed by the simulation model. Moreover, milling experiments were conducted to validate the simulation results. It is observed that the surface roughness of the simulation and experiment shows the same trend with the increase of feed per tooth and depth of the cut, which verifies the simulation model. Moreover, the superficial residual stress of the machined surface is the result of the coupled thermo-mechanical with the compressed effect of the tool, the tensile effect of the tool, and thermal load. The superficial residual stress of the machined surface presents compressive stress at a different feed per tooth and spindle speeds. Current findings provide insights for understanding the formation mechanism of the surface topography and residual stress in milling aluminum alloy.