Study on Ultrasonic-Assisted Laser Machining of Si₃N₄

Abstract

Si3N4 is difficult to be machined due to its hard and brittle nature. In order to improve its machining quality, a new method of ultrasonic-assisted laser machining is proposed. The machining device is established including Nd: YAG pulsed laser, ultrasonic vibration stage and water flow system. Etching experiments of laser machining with and without sample vibration in anhydrous conditions and in water conditions are studied respectively. A VM-3030E two-dimensional image measuring instrument is applied to detect shape and measure dimension of the sample. Microstructure morphology of the sample is observed by a JSM-7500F scanning electron microscope. Experimental results show that there are fewer slags on inner surfaces of V-shaped grooves when laser machining with water flow. The surface quality and depth-to-width ratio of grooves machined by laser with vibration on sample are improved significantly in comparison with those without vibration. The depth-to-width ratio of groove machined by laser with 90.1W vibration power is near twice than that without vibration.