Experimental Study Of Laser Milling On Al₂O₃ Ceramic

Al₂O₃ ceramic materials has many excellent properties, such as high insulated property , excellent heat-resistant, high wearability and good erode-resistant property, it is applied in electronic industry and mechanical industry widely. But it is very difficult for using conventional methods to machine ceramic, which all have some faults, for example, lower machining efficiency, lower machining quality and tools are worn out severely. Technology on machining ceramic needs to be improved urgently.It is a development for laser milling being applied on machining ceramic. During laser milling, the machining tools do not need to touch workpieces directly, the workpieces can keep off mechanical force action, so laser milling is a promising method. However, laser milling still can not be applied in practice now, it needs farther researching, the following contents have been done in this thesis:(1) According to YAG laser property, a proper heat conduction equation is selected to calculate the power density threshold of laser milling. This part of work supplys foundation for choosing proper milling parameters(2) The researches on theory and technique of laser milling with assistant blowing are done. The discipline that crater dimension influenced with pulse width, output power and defocus distance is researched, and the result of experiment is analyzed based on the knowledge of heat conduction and the power distributing, this part of work supplys theory foundation for milling in large area. In the overlap coefficient selecting experiment, proper overlap coefficient for getting smooth milling surface is chosen. Some researches on the disciplines of milling effect influenced with defocus distance, output power and assistant gas pressure are done, material removing model is created, the essentiality to forming the removing path is mentioned in this part of work. Based on optimizing parameters selecting , some researches on multi-layers milling are done.(3) The researches on theory and technique of laser milling based on deteriorative layer without assistant blowing are done. Element composition and crystal phases of deteriorative layer are analysed by using energy spectrum analysis method and XRD analysis method. And then the forming course and desquamating reason of deteriorative layer and milling surface roughness are also researched Based on researching the discipline of milling effect influenced with overlap coefficient, output power and defocus distance, optimizing parameters is used to milling ceramic in large area, the result shows that the surface roughness can reach 3μm. And...