Impact of a diamond coating on tool wear behaviour during dry machining of a multidirectional composite materials

Abstract
High mechanical performances and lightweight are the principal characteristics of composite materials. However, the main problems encountered when machining these materials are their poor machinability and the short timelife of the tools. Hard diamond coatings are attractive for cutting processes due to their high hardness, low friction coefficient, excellent wear resistance and chemical inertness. In the current study, damage mechanisms of the uncoated tungsten carbide are compared to the coated one. Tool wear behaviour was investigated at different cutting conditions when dry machining the multidirectional carbon/epoxy composite T300/914. The purpose is to determine the effect of the cutting parameters (cutting conditions, forces, temperature, etc.) on the tool-workpiece interface (surface integrity, roughness). The experiments have been carried out under orthogonal cutting configuration for both tools: uncoated and coated cemented carbide WC-Co. Different coatings have been tested: diamond coating (thin and thick diamond layer), and Diamond-Like Carbon (DLC coating). Three rake angles of 0, 15 and 30, two cutting speeds of 6 and 60 m/min and three feeds rates of 0.05, 0.1, 0.2 mm were tested. The tool surface topography was analyzed using complementary techniques such as white light interferometry, scanning electron microscopy (SEM) and Auger electron spectroscopy (AES).