Wear behaviour of cemented carbide tools in dry machining of aluminium alloy
Résumé
Several causes of tool wear have been investigated in dry machining of aluminium alloy with cemented carbide insert; some of the most important are: adhesion and diffusion. The formation of built-up edge (BUE) and adhesive layer on the tool rake face degrades on the one hand, the shape and efficiency of cutting tool and on the other hand, the surface quality and dimensional accuracy of the finished product. This paper describes tool wear mechanisms in dry machining of a usual aluminium–copper alloy (2024) with an uncoated cemented carbide tool (WC–Co). Orthogonal cutting tests were performed using an instrumented planer machine. The morphology of chips, cutting forces and contact lengths were analyzed for several cutting conditions. The tool–chip interface temperature and the average pressure were calculated by conducting calibration–cutting experiments in conjunction with FEM simulations. This allowed to define the contact parameters associated with different cutting conditions on the tool rake face. High-speed camera movies (CCD), white light interferometry, scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDS) and Auger electron spectroscopy (AES) were investigated to show the development of the built-up edge and the adhesive layer on the tool rake face during machining process. The results confirmed that the wear mechanisms involve the activation of the chemical and the diffusional phenomenon.