Evaluation of Nanosecond-Pulsed Laser Milling as a Roughing Process for Hybrid Machining of Cemented-Carbide Dies

Hybrid machining combining laser and mechanical processes has attracted increasing attention for improving the machining efficiency of hard-to-cut materials. In this study, a sequential hybrid machining concept is proposed in which nanosecond-pulsed laser milling is used for rough material removal before mechanical machining. First, the effects of laser-processing conditions on material removal and surface morphology were investigated to identify suitable rough-machining conditions. Based on these results, the proposed sequence, in which laser milling removes bulk material followed by mechanical machining for dimensional correction and surface finishing, was evaluated using computer-aided manufacturing (CAM)-based machining-time estimation. The proposed hybrid strategy was compared with conventional machining using mechanical cutting alone. The CAM analysis estimated machining-time reductions of approximately 44% for an idealized case without laser-induced taper and 36% when the experimentally observed taper was incorporated into the model. These results indicate the potential of nanosecond-pulsed laser milling as a rough-machining process for cemented-carbide die and mold manufacturing, while subsequent mechanical machining is required to compensate for surface and geometric limitations.