Analysis of Burr Formation Mechanism in Orthogonal Cutting

Abstract

To prevent problems caused by burrs in machining, reduction and control of burr size is desirable. This paper presents a basic framework for and conceptual understanding of the burr formation process based upon the material properties of the workpiece. In order to verify this framework and explain the basic phenomena in the burr formation process, the deformation at the edge of the workpiece was analyzed using a finite element method (FEM). Micro-machining tests under an optical microscope and a scanning electron microscope using AI-2024-O material were also done to observe the burr formation process. The feed rate and tool edge radius were varied and the resulting burr formation observed. FEM analysis of burr formation in the 2024 material and observation of the deformation at the workpiece edge in the micromachining tests verified the proposed conceptual understanding of the burr formation process. For the experimental conditions examined, all of the burrs in AI-2024-O were "negative" burrs, that is, edge breakout. As the feed was increased two effects were observed. One effect was an increase in the resulting burr thickness. Another effect, which was observed during the burr initiation stage while machining with a sharp tool, was an increase in both the distance and depth of the initial pivoting point of the burr from the tool edge.

Fundamental study of exit burr formation mechanisms during orthogonal cutting of AlSi aluminium alloy

“…While the tool continues the cutting, the fracture strain limit has been reached and a crack appears (t + 0.2 ms). After t + 0.2 ms, the plastic deformation generates a small breakout, as described by Hashimura et al (1999a).…”

“…According to Hashimura et al (1999a) different burrs are produced with respect to workpiece material. During the cut of a ductile material, the burr formed is similar to a rollover burr and is called "positive burr".…”

Review of Geometric Solutions for Milling Burr Prediction and Minimization

“…Unfortunately, precise estimation of the instant chip flow angle is extremely difficult, particularly in the milling operation. However, it can be approximated to a large extent by the insert orientation with respect to the workpiece edges, which corresponds to the tool exit order sequence (EOS) [10,11]. The geometry of a face milling cutter is shown in Figs 4 and 5.…”

A simple analytical model for burr type prediction in drilling of ductile materials

“…The modes of burr formation in exit of drilling as well as the influential parameters have already been studied through empirical methods, based on experimental observations,. In [3], the authors give qualitative information on how to reduce burr size, on cutting angles and cutting condition and in [4] and [5] the burr formation stages are detailed, giving indications on the influence of cutting angles on final bur height. Theses papers do not directly deal with the specific problem of drilling.…”