Wear characteristics of single diamond grit scratching on sapphire with different contact forms

Abstract

Abrasive single crystal diamond (SCD) is widely used in the machining process of sapphire. The wear characteristics of SCD grit have a significant influence on the tool wear and machining precision of sapphire. However, the influence of grit-workpiece contact form on the wear characteristics of SCD grit scratching on sapphire is not clear. In this paper, the wear characteristics of single SCD grit scratching on sapphire with three different grit-workpiece contact forms (point/line/face) are systematically investigated. Wear volume, wear morphology and scratching force are measured and tracked. Stress models of different contact forms are further established and analyzed. The results show that the SCD grit with face contact form can remove the most sapphire volume and it is the most wear-resistant. The SCD grit with point contact form can remove the fewest sapphire volume and it is the most prone to cleavage and fracture. Smaller stress results in more wear-resistant of the SCD grit during scratching on sapphire. Contact form is closely related to the stress state and has an important influence on the wear characteristics of SCD grit. The investigation results could provide a theoretical basis for the fabrication of abrasive tools.