Tool wear behaviors and its effect on machinability in dry high-speed milling of magnesium alloy

Abstract

This present study aimed at the wear behaviors of uncoated carbide tools and its effect on machinability in dry milling of magnesium alloy at high cutting speeds. Through the experimental observations, the dominant wear mechanisms for the carbide tool were determined, namely adhesion, abrasion, and diffusion wear. Compared to lower speed, the experimental results indicated that the higher speed could bring much better surface quality in the steady wear stage; however, the duration of this stage was shorter than the lower. Within each steady wear, surface roughness declined gradually with the increasing cutting edge radius. Meanwhile, a mass of workpiece material piled up the stagnant zone below the cutting edge on the flank face, causing the flank built-up edge formation. Besides that, the built-up edge accumulated to a certain size that is beneficial to improve the machined surface quality. In addition, the chip morphologies depended on the severity of the tool wear. The cutting tool during the early period of cutting operation predominantly produced inerratic flake chips. However, with the development of built-up edge, there was a great quantity of threadlike chips formed, as well as the plentiful needlelike chips.