Fabricating diamond bit by selective laser melting and its drilling performance evaluation

Abstract

Diamond abrasive tools play an important role in efficient and precision machining of difficult-to-cut materials. As the traditional tool manufacturing process is difficult to meet the integrated molding preparation of complex structures, the use of selective laser melting (SLM) technology to manufacture diamond tools with functions and structures has become a research hotspot in recent years. In this paper, the feasibility and wear characteristics of diamond bits prepared by SLM using AlSi7Mg as metal matrix are investigated. The optimal parameter combination of diamond/AlSi7Mg mixture was obtained through orthogonal experiments, in which the powder layer thickness was 30 μm, the laser power was 300 W, the scanning speed was 3000 mm/s, and the scanning spacing was 120 μm. This parameter combination realized the improvement of the mechanical properties and the decrease of the porosity. Two types of bits with and without groove-structure (Labeled as Bit-G and Bit-N) were fabricated and their drilling performance were compared by processing BK7 optical glass. The results show that the Bit-G has more excellent machining performance, including lower drilling force, better hole quality and longer service life. According to the simulation results, the self-sharpening cycle of the Bit-G’s wear characteristics can be attributed to the groove structure that allows the coolant to be fully utilized in the bit/workpiece contacting area. This paper demonstrates the feasibility of the SLM process for the preparation of diamond tools and comprehensively analyzes the wear process, which provides reference value for further research on this process for the manufacturing of diamond abrasive tools.