Characteristics of High-Speed Milling of WC-Co Cemented Carbide Using Diamond-Coated Carbide End Mill

This study aims to improve the efficiency and precision of high-speed milling WC-Co based cemented carbide (WC-Co) using the chemical vapor deposition (CVD) diamond-coated carbide tools. Side cutting experiments are carried out to clarify the characteristics of high-speed milling WC-Co. At a considerably high cutting speed of 400 m/min, both the cutting force and the tool flank temperature during milling are measured by the highly responsive measuring instruments. The cross sections of the chips are observed to evaluate the structure change and the chip thickness. The tool wear is evaluated by the width of flank wear. The increase in a cutting speed from 100 to 400 m/min decreases a radial component of cutting force from 44.0 to 27.9 N at a cutting length of 110 m, and conversely increases a tool flank temperature from 385 to 880 °C. In addition, the chip thickness decreases, and the tool flank wear is suppressed with increasing cutting speed. These suggest that the increase in the cutting temperature reduces the hardness of the workpiece material and the friction force between the chip and the tool rake face. In terms of tool wear, the thermal wear is suppressed by the heating and cooling cycle of the intermittent cutting.