Investigation of edge damage of the hole and adhesive wear of the tool in ultrasonically assisted step drilling of SiCp/Al composites

Abstract

Owing to their superior comprehensive performance, silicon carbide particle-reinforced aluminum matrix (SiCp/Al) composites are extensively utilized in various domains such as semiconductors, aerospace, transportation, and military applications. When drilling SiCp/Al composites using conventional methods, significant drilling force and high temperature often cause severe edge damage at the hole exit and adhesive wear on the flank face. In this paper, a step drill was designed and the effects of tool geometry and machining parameters during ultrasonically assisted drilling (UAD) of SiCp/Al composites were investigated. The tool geometry parameters include diameter ratio (0.6, 0.8, and 1), length of the first step drill (0 mm, 3 mm, and 6 mm), and point angle. As well as machining parameters such as spindle speed, feed rate and ultrasonic power supply voltage (which determines the amplitude of ultrasonic vibration). This paper focuses on the effects of tool geometry and machining parameters on drilling force, temperature and plasticity of the aluminum matrix, and then explores their combined effects on edge damage and adhesive wear. The results show that the diameter ratio and length of the first step drill are the primary factors influencing drilling force and temperature. The machining parameters have a limited effect on the drilling force but a larger effect on the drilling temperature. An appropriate drilling temperature enhances the plasticity of the Al matrix, reducing edge damage and adhesive wear. The experimental results show that when the thickness of SiCp/Al composites workpiece is 4 mm and the step drill with a diameter ratio of 0.8 and a length of a first step drill of 6 mm is used for drilling, the edge damage at the hole exit and the tool adhesive wear are the least. This study aims to provide theoretical and experimental basis for the improvement of drilling quality and reduction of tool wear in practical machining of UAD of SiCp/Al composites by taking into account the effects of more factors.