Wear and breakage behaviors of PCD small-diameter end-mill: a case study on machining 2A12 aluminum alloy

Abstract

Small-diameter end-mill is a key element for micro-machining technique. It is a new attempt to manufacture a small-diameter tool with polycrystalline diamond (PCD), which is also a hot issue in the research area of micro-manufacturing. PCD end-mills with small-diameter were fabricated and utilized in micro-milling. With a contact simulation model, the stress distribution and potential crack propagation of the PCD tool was revealed via 2D finite element (FE) analysis of 2Al2 aluminum alloy acting on the tool surface. Thereafter, a series of machining experiments on 2A12 micro-part were carried out with the PCD small-diameter end-mill. The wear characteristics of the rake face and flank face were analyzed, and the wear mechanisms of small-diameter end-mills were carefully investigated by using scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectroscopy. Three typical breakage morphologies of PCD end-mills were demonstrated while machining the aluminum alloy workpiece, i.e., the breakage of the tool tip, the edge chipping, and the peeling off of PCD layer. The consequent experiment results showed that abrasive wear, adhesive wear, and oxidative wear were the predominant characteristics in the damage region of PCD small-diameter end-mill. The effect mechanisms of various wear characteristics were also analyzed and revealed in detail. The experimental results were discussed according to the simulation results and effects on failure behavior of the PCD tool. The research can provide a better understanding for the wear and breakage behaviors of the downsized PCD tool in machining aluminum alloy and underpin the development of micro-milling process with diamond tool.