Effects of tailored residual stress on micro end milling: numerical modelling and validation

Abstract

Abstract Precision components often require micro-milling, where burrs may occur as surface defects. Such defects are likely to be influenced by the stress state in the raw material prior to micro-milling. A pre-treatment on the surface is found to compensate for the formation of burrs and improve the finishing of the micro-milled component. A finite element model of the micro-milling process was developed in Abaqus. An enhanced flow algorithm based on strain-gradient and dynamic recrystallization was used, along with a tool/workpiece friction model. This study revealed that compressive residual stress of about 613 MPa in Ti-6Al-4V can lower burr formation by up to 60%, cutting temperatures by 7% and contact forces by 15%. Additionally, surface residual stresses induced by micro-milling are predicted for compressively pre-stressed and as-received samples. The mechanism of burr formation, cutting forces, and cut marks on the sidewall surface were reported. The simulated burr morphology, chip contact length, cutting forces and surface residual stresses after micro-milling were verified with experimental results.