Suppression of tool wear by extremely short-duration cutting

Abstract

High-speed cutting has various advantages such as high material removal rates and reduction of machining time. However, the greatest problem of high-speed cutting is its excessive tool wear rate. This is attributed to the fact that high-speed cutting causes a large cutting temperature rise and then, promotes the occurrence of tool material diffusion. In this study, we focused on extremely short-duration cutting. If the cutting duration for each edge undergoing the intermittent cutting process is designed to be considerably smaller than the time constant of thermal diffusion, the temperature rise at a tool face can be suppressed to a low value; i.e., the diffusion wear due to temperature can be reduced. In this method, since the cutting volume of a single pass is small, in order to cover the total cutting volume as in is the case of ordinal cutting, the number of cutting cycles is increased. Thus, mechanical wear will increase with a shortening of the cutting period. Therefore, to reduce the total wear volume in extremely short-duration cutting, we need to design tool edge geometries that can lessen mechanical wear and investigate the optimum cutting period in which the tool wear can be minimized. In this study, we investigated the effect of the tool rake angle and the inclination angle on the wear volume. Then, we measured the tool temperature and the wear volume for various cutting periods during a single pass and at different cutting speeds. Consequently, we found that the smaller the cutting duration, the smaller are the temperature rise at the flank face and the tool flank wear. Several experiments suggested that extremely short-duration cutting has a high potential for achieving high-efficiency metal removal.

Keywords

• high-speed cutting
• tool wear
• temperature reduction
• edge preparation
• carbide tools