Mechanical micro-machining of hard brittle materials: a perspective review

The escalating demand for miniature components in high-precision industries continues to drive advances in micro-scale manufacturing technologies. Mechanical micro-machining must accommodate an increasingly wide range of materials at small scales, including hard and brittle systems, which present significant challenges in tool development and process optimization. This work presents a comprehensive review of recent developments and future directions in the mechanical machining of hard and brittle materials, focusing on three material groups, cemented carbides, ceramic composites, and glass ceramics. Key influencing factors are systematically analysed, including size effects, minimum uncut chip thickness, micro-tool design and materials, ductile–brittle cutting regimes, machining strategies, surface integrity, defect formation, and machine-tool platform characteristics. The review emphasizes the importance of understanding fundamental micro-milling principles and accurately identifying cutting regime transitions, both of which are critical for advancing the precision micro-machining of hard materials and guiding future research in tool design, process optimization, and microscale manufacturing science.