Silicon carbide and silicon nitride ceramic composites are hard, brittle, and difficult-to-machine materials. Drilling micro-holes into such materials is challenging and time-consuming. Proper equipment, cutting tools, and machining program are the key to success. At beginning, high-efficient hole making is achieved using millisecond lasers. Then, the diameters of pre-drilled holes, laser processing parameters are determined by simulation and experimental verification. Thermal-induced defects such as heat-affected zones and re-cast layers are effectively controlled within tolerance. Next, ultrasonic vibration-assisted machining is employed to prepare the finished holes, reducing the contact time and friction effects between the tool and the workpiece. Finally, super-hard, wear-resistant PCD (polycrystalline diamond) drill bits are used together with ultrasonic toolholders. This approach effectively removes defects such as heat-affected zones and re-cast layers generated during the laser pre-fabrication process, achieving high-precision and high-quality micro-hole machining.
