Study On Microwave Focusing Technique And The Induced Crack Cutting Experiment Based On It

Engineering ceramics，for its excellent physical and mechanical properties，is widely used in the aerospace, machinery, automobiles, light industry, chemicalindustry and other industries. Because of high hardness and brittleness,engineering ceramics is a typical refractory materials. In order to overcome the alot of problems produced by the traditional machining methods, this paperproposed a method based on thermal cracking an application of focusedmicrowave cutting engineering ceramics technology. This study includes:microwave focusing waveguide design and finite element analysis for focusingproperties, microwave and ceramic material effect heat regularity theory and theanalysis, temperature field simulation and microwave microwave heating ofsilicon nitride ceramic plate cutting machine，Process test of microwave cutting.Using the theory of electromagnetic field and electromagneticwave,analyze the impact of the transmission waveguide shape and size onmicrowave transmission characteristics, design a quasi optical focusing systemwith conical horn and focusing lens. Using HFSS software, the focusingproperties of the quasi optical focusing system is simulated, at last we got thecircular focusing spot, and analyzed the effect law of microwave frequency onthe focal spot area.For the widely used microwave(2450MHz), propose the tapered waveguidefocusing system. Conduct the simulation analysis of the influence of the shapeand size of the tapered waveguide on focusing characteristics.Based on heat transfer theory, the heat transfer of microwave heating ofceramic materialsmechanism was analyzed, the simulation model of temperaturefield and thermal focused microwave beam heating plate of silicon nitrideceramic materials stress field are established. The simulation results show that:the process of microwave heating is body heating, the tapered waveguidefocusing properties meet the technical requirements of thermal crack controlmethod for cutting ceramic technology.Design the microwave experimental device for cutting processing,experimental study was carried out to investigate the influence law of the tapered waveguide focusing properties and processing parameters on temperature field.Preliminary results show that:cutting ceramic material by focused microwavebeam is a new processing technology which has broad prospects fordevelopment.