Laser-assisted machining of difficult-to-cut materials: A systematic review

: Laser-assisted machining (LAM) has become an important approach for the high-efficiency and low-damage machining of difficult-to-cut materials, particularly in the machining of advanced and emerging material systems. By introducing a controllable laser energy field into conventional material-removal processes, LAM modifies the local material state before or during mechanical removal process, thereby regulating deformation, fracture, interfacial interactions, and surface generation. Although extensive studies have been reported, the understanding of LAM remains fragmented, and a unified analysis of its mechanisms, process routes, and performance consequences is still needed to support its wider implementation. This review summarizes the development, principles, implementation strategies, material-removal mechanisms, surface integrity, tool wear, and major challenges of LAM from a process-principle perspective. Emphasis is placed on two main routes: laser thermal-softening-assisted machining and laser modification-assisted machining. The removal behavior and surface/subsurface integrity of representative difficult-to-cut materials, including metallic alloys, steels, ceramics, glasses, cemented carbides, composites, semiconductors, and optical single crystals, are analyzed. The review shows that LAM is not merely a method for reducing machining resistance, but also a means of reconstructing process–material interactions to regulate both the removal mode and the surface-layer state. Future research could focus on material-centered process design, multiphysics modeling, in situ monitoring, service-oriented high-performance machining, and robust industrial integration.