Improvement in the abrasion resistance of cutter blades by laser processing

Commercial cutter blades are widely used as disposable industrial tools, generating large material consumption and waste. Extending blade lifetime through simple post-processing could therefore contribute to improved resource efficiency. In this study, we demonstrate the feasibility of improving the abrasion resistance of mass-produced cutter blades using underwater laser peening with a 5-ns pulsed laser. The cutting performance was quantitatively evaluated using a sharpness tester under constant load conditions. Compared with untreated blades, laser-processed blades exhibited an approximately twofold increase in the maximum cumulative cutting distance, although a slight reduction in initial sharpness was observed immediately after processing. Vickers hardness measurements showed an increase from approximately 600 HV0.5 to 820 HV0.5, indicating surface hardening induced by laser peening. The sharpness tester was found to provide a practical and reproducible metric for evaluating abrasion resistance in laser-processed cutting tools. Although the present study does not aim at systematic parameter optimization or detailed microstructural analysis, the results demonstrate the practical potential of underwater laser peening as a simple post-processing technique for extending blade lifetime and highlight the applicability of sharpness testing as a quantitative evaluation tool.