Ultrasonic Vibration-Assisted Micro-Electrical Discharge Machining Characteristics and Parameter Optimization of C/SiC Composites

Carbon-fiber-reinforced silicon carbide (C/SiC) composite materials, as a kind of composite material with the characteristics of ceramics, have the following characteristics: high strength, high stiffness, low density, high temperature resistance, and high corrosion resistance. These characteristics make them widely applicable in aerospace, defense, automotive, and other high-performance industries. However, because of their anisotropy and inherent brittleness, ceramic-based composites are still difficult to process using conventional processing techniques. In this study, a technique of ultrasonic vibration-assisted micro-electrical discharge machining (micro-EDM) for the precise machining of two-dimensional (2D) C/SiC composites was proposed. The research mainly focused on an investigation of the material removal mechanism of C/SiC composites under ultrasonic vibration-assisted micro-EDM conditions. The erosion process was found to involve melting and vaporization of the SiC matrix, whereas the carbon fibers were removed by fragmentation and localized melting. In order to assess the effects of various process parameters on the material removal rate (MRR), single-factor experiments were performed initially. Afterwards, response surface methodology was used to optimize the MRR of C/SiC composites during ultrasonic vibration-assisted micro-EDM. A Plackett-Burman (PB) design was used to determine the parameters that have a significant effect on MRR. Based on these results, the optimum parameter range was obtained using the method of steepest ascent. Finally, a Box-Behnken design was used to determine the best machining parameters for improved performance.