High Precision Turning of Hardened Steel by Use of PcBN Insert Sharpened with Short Pulse Laser

Precision grinding is one of the important processes for finishing of hardened steel parts. However, the grinding process might be quite costly providing the parts with shape complexity should be finished because a number of production steps are needed. Also, this process has some environmental issues, such as disposal of a large amount of grinding sludge and grinding fluid. Precision cutting would become a better alternative process to reduce cost and environmental burden because process steps can be simplified by use of CNC machine tools with PcBN cutting insert if deterioration of cutting tool edge by wear and chipping can be suppressed for long duration. In this study, to improve performance of a PcBN cutting insert, such as wear resistance and defect resistance by the applying of pulse laser processing to sharpen cutting edge in order to realize substitution of cutting for grinding. Precision cutting experiments for hardened steel are conducted by use of the PcBN insert with sharp and tough edges processed by pulsed laser and, for comparison, by use of the PcBN insert ground with diamond wheel. From the results of cutting experiments, it was found that precision cutting with PcBN insert processed by pulsed laser can provide a steady cutting state for a long cutting duration, and a smooth finished surface comparable to precision grindings.