New method to characterize a machining system: application in turning

TL;DR

This paper introduces an experimental method to accurately characterize the three-dimensional elastic behavior of machining systems, including machine tool, tool, and workpiece, using a novel static approach and matrix stiffness modeling.

Contribution

It develops a new experimental procedure for 3D static characterization of machining systems, integrating matrix stiffness and displacement analysis with Castigliano's theory.

Findings

Determined the 3D stiffness matrix of machining components.

Identified the static displacement plan of the tool tip.

Provided insights into the system's behavior during self-induced vibrations.

Abstract

Many studies simulates the machining process by using a single degree of freedom spring-mass sytem to model the tool stiffness, or the workpiece stiffness, or the unit tool-workpiece stiffness in modelings 2D. Others impose the tool action, or use more or less complex modelings of the efforts applied by the tool taking account the tool geometry. Thus, all these models remain two-dimensional or sometimes partially three-dimensional. This paper aims at developing an experimental method allowing to determine accurately the real three-dimensional behaviour of a machining system (machine tool, cutting tool, tool-holder and associated system of force metrology six-component dynamometer). In the work-space model of machining, a new experimental procedure is implemented to determine the machining system elastic behaviour. An experimental study of machining system is presented. We propose a machining system static characterization. A decomposition in two distinct blocks of the system "Workpiece-Tool-Machine" is realized. The block Tool and the block Workpiece are studied and characterized separately by matrix stiffness and displacement (three translations and three rotations). The Castigliano's theory allows us to calculate the total stiffness matrix and the total displacement matrix. A stiffness center point and a plan of tool tip static displacement are presented in agreement with the turning machining dynamic model and especially during the self induced vibration. These results are necessary to have a good three-dimensional machining system dynamic characterization.