Jean-François Rigal

Finite-element-based hybrid dynamic cutting model for aluminium alloy milling

Abstract The present contribution deals with milling tool vibration effects on chip morphology, cutting force, and cut surface topology. The study concerns an orthogonal down-cut peripheral milling case for aeronautic aluminium alloy A2024-T351. A finite-element-based hybrid dynamic cutting model (HDC model) is proposed to predict the chip morphology under dynamic cutting conditions. The latter is conceived with commercial software ABAQUS®/EXPLICIT and combines the stiffness of a high-speed milling spindle system (tool, toolholder, and rotor) with the chip formation process. A qualitative parametric study with various stiffness and damping coefficient values for a high-speed milling spindle system has been performed. The results concerning chip morphology and cutting force are compared with experimental data, while the surface profiles are compared with those obtained by considering a perfectly rigid spindle system. As expected, a less rigid undamped milling system generates higher-amplitude tool vibrations during milling. In this situation, the temperature rises at the tool—workpiece interface, enhancing material softening. This softening promotes chip segmentation and increases waviness of the machined surface profile. The numerical results show that higher values of cutting speed and uncut chip thickness are associated with higher vibration amplitudes.

A Model for Simulation of Vibrations During Boring Operations of Complex Surfaces

Abstract The dynamics of the cutting process, as well as the behaviour of the piece and the tool, have a strong influence on the quality of the machined surface, particularly in the boring operations of complex surfaces with thin walls. On the basis of a parameterized model of the tool-material interaction, a linear FEM model describing the behaviour of the workpiece, tool and their contact is presented. The frequency responses are processed and the simulation extends with a mixed procedure (FEM analysis and simulation using Matlab). The purpose is to characterize the stability conditions of the cutting process.