Improvement of Cutting Forces Modeling Based on Oriented Cutting Tests

Abstract

International audienceIn order to predict the characteristics of the machined part, such as geometry, surface roughness and fatigue or corrosion resistance, the cutting forces values should be known as precisely as possible. The edge discretisation methodology can be used to model the three components of the cutting forces. The results are generally considered as suitable, even if the considered cutting operation is complex, because the geometry is well described. Usually, the local cutting forces model is identified from orthogonal or oblique cutting tests and the local contributions are assumed to be independent of the orientation of the elementary edge in the reference plane Pr. However, when turning in the tool nose or with round inserts, the tool cutting edge angle Kr (or Side Cutting Edge Angle) evolves along the active cutting edge and the values of this angle are very small compared to that of 90° used in orthogonal/oblique cutting. For this study, a new elementary cutting operation, called "oriented cutting", has been tested. In this configuration, the active cutting edge is rectilinear, without inclination, but oriented by an angle Kr different from 90°. In addition, cylindrical turning tests have been done. The measurements, performed in pure copper, show an influence of the tool cutting edge angle on the cutting forces. An interaction between Kr and the workpiece radius is also highlighted

A generalised geometrical model of turning operations for cutting force modelling using edge discretisation

“…The clearance angle and the edge radius r β are rarely considered, but they could be introduced. Recent work suggests that the cutting edge angle κ r and the radius of curvature of the workpiece R W o should also be taken into account [41]. In order to calculate the uncut chip thickness, it is helpful to have a definition of the cutting edge in a coordinate system linked to the workpiece.…”

Analysis and Modelling of the Contact Radius Effect on the Cutting Forces in Cylindrical and Face Turning of Ti6Al4V Titanium Alloy

“…representative of a finishing operation in the tool nose), several geometrical parameters are not constant along the cutting edge engaged. It is the case of the uncut chip thickness [12], the cutting edge lead angle [15] but also the clearance face contact radius, as explained and presented in Fig. 2.…”

“…However these formulations, relating the ploughing force to polynomial functions of the uncut chip thickness or the cutting speed, can be discussed. Indeed studies concerning the determination of ploughing force are often developed on planning tests, and so doesn't take into account the potential influence of the part diameter, as suggested by Germain or Campocasso et al [14,15]. Therefore the purpose of this study is to enhance the modelling of the ploughing force by analysing the contact radius effect on cutting forces.…”

An innovative experimental study of corner radius effect on cutting forces

“…The shape of the curves, non-monotonic, suggests that two contradictory phenomena are involved. However, at this step of the analysis, these conclusions must be nuanced, because the highest levels of forces for 6 r  mm and the rectilinear edge, can be respectively due to the highest edge radius and the effective workpiece radius -which is equal to infinity when orthogonal cutting on tube, as explained in [12] -.…”

“…The principle of the corner tests has been already used with a rectilinear cutting edge and an axial feed rate, in order to study the effect of the cutting edge angle r  on the local forces [12]. For both configurations, the uncut chip thickness h along the active cutting edge can be expressed, on the main part of the edge, using Equation (2); where  is the current polar angle defined from the bisectrix.…”