The Removal Mechanism of PcBN Material by Femtosecond Laser

This study compares the material removal mechanisms and thermal effects of femtosecond and nanosecond lasers on polycrystalline cubic boron nitride (PcBN). Using 800 kHz femtosecond and 35 kHz nanosecond lasers, the surface morphology and phase evolution were analyzed via SEM, EDS, and XRD. Results show: femtosecond lasers preferentially remove the AlN binder via ultrashort pulses—evaporation dominates at 0.5 W, while cBN fracture occurs at 1.3 W. Nanosecond lasers induce cBN-to-hBN phase transition and rough surfaces due to thermal accumulation. At 10 W, femtosecond-processed grooves exhibit smooth walls, whereas nanosecond lasers generate cracks and recast layers. XRD confirmed no hBN phase in femtosecond-processed regions, but minor hBN peaks in nanosecond-processed samples. High-repetition-rate femtosecond lasers demonstrate superior performance in minimizing thermal damage and enhancing machining quality.