Frictional Characteristics of the Surface Formed by Machining Combined with Laser Heat Treatment (2nd Report) (Surface Formation Mechanism at Cutting and Influence of Lubricant Viscosity on Static Frictional Force)

Abstract

The authors have reported that the micro wavy surface formed by machining combined with laser heat treatment have higher static coefficient of friction compared with the surface finished by polishing or cutting. Therefore, this study was carried out to clarify the surface formation mechanism in order to control micro wavy height and the influence of lubricant viscosity on static frictional force. In practical use, high viscosity lubricant is used in wet brake to prevent oil leakage. At cutting after laser heat treatment, when the higher thrust force was, the higher micro wavy height was obtained. Thus, decreasing cutting speed or increasing feed rate, the obtained micro wavy height became higher.The static coefficient of friction of surface finished by polishing was decreasing with lubricant viscosity. This tendency was also seen at micro wavy surface. However, the static coefficient of friction of micro wavy surface was constantly higher than polished surface regardless of lubricant viscosity.