Dynamics of 2-DOF Micro-End-Milling System Considering Grain-Size Variation
Résumé
Non-smooth systems are employed to model different cutting processes including milling and oil drilling. This article deals with the modeling of the micro-end-milling dynamics with inhomogeneous materials. The model considers a non-smooth system composed of a primary system that represents the tool and a secondary system, representing the workpiece. This system mimics micro-end-milling dynamics considering a progressive motion of the tool holder with tool run-out. The relative position of the tool holder and the chip is evaluated avoiding huge displacements of the tool tip when the tool is not in cutting. The simplified dynamics presented in this article is used as a methodology to calculate the cutting force and tool performance from the prescribed trajectory. The inhomogeneity is related to the description of the micro-machining process where material properties cannot be considered as constant due to grain structure as the tool moves for cutting. Numerical simulations consider a situation where the grain workpiece has austenitic, ferritic or ferritic-austenitic phases. Microscopic analysis is employed to obtain the property variations. The main goal is to establish a qualitative comprehension of the system dynamics comparing results with homogeneous material cutting process.