Prediction and experimental validation of micro-milling cutting forces of AISI H13 steel at hardness between 35 and 60 HRC

摘要

This paper presents prediction and validation of micro-milling cutting forces of AISI H13 steel at hardnesses between 35 and 60 HRC. The cutting forces are predicted based on an approach considering the full kinematics of the cutting tool including the run-out effect, effects of the cutting velocity and tool geometry, ploughing and chip formation phenomena and the hardness of the AISI H13 steel. A plane strain dynamic thermo-mechanical finite element (FE) model of orthogonal cutting is used to predict the cutting forces where the geometry of the cutting tool edge is modelled based on scanning electron microscope measurements. A constitutive elastic–plastic isotropic material model describing the relationship between stresses, strains, strain rates and hardnesses is modelled and implemented into ABAQUS/Explicit FE code by the user-defined subroutine VUMAT. Finite element analyses (FEA) are employed to obtain the relationship between cutting forces, uncut chip thickness, cutting velocity and material hardness. Numerous FEA are performed at different uncut chip thicknesses (0–20 μm), cutting velocities (104.7–4,723 mm/s) and hardnesses (35–60 HRC) using the FE model of orthogonal cutting. The full kinematics of the cutting tool including the run-out effect and the FE-predicted cutting forces are incorporated to predict the micro-milling cutting forces. The predicted micro-milling cutting forces have been experimentally validated at hardness of 43.2 HRC at different feed rates and spindle speeds. The result showed that the cutting forces and cutting temperatures increase by increasing the hardness of the AISI H13 while the stability limits of the process decrease by increasing the hardness.