Study On The Process And Mechanism Of Rotary Ultrasonic Assisted Machining For Difficult-to-machine-materials Complex Parts

Advanced materials, such as ceramics, silicon, sapphire and high temperaturealloy, are widely used in the fields of optics, semiconductor and aerospace. As it isdifficult to machine these materials, an efficient and high quality machining methodhas become the research focus in the field of manufacture. Ultrasonic machining isone of the key technologies in machining with the advantages of high machiningefficiency, low cost, and easy to achieve large quantities of automatic production. Thisthesis designed a Rotary Ultrasonic Machining (RUM) attachment device, andassembled it on the five axis machine. This supplied a reliable platform for themachining of advanced materials mentioned above. The processing device could notonly drill holes and milling groove, but also could machine advanced materials withmore complicated morphology and structures.This thesis proposed a three level influencing factor model based on the analysisof the mechanism of edge chipping fracture in brittle and hard materials machining.By finite element method, a detailed analysis in ultrasonic drilling and milling edgechipping fracture is conducted. Additional supports and improved tool path wereproposed to reduce edge chipping in drilling and milling. The method had beensuccessfully used in brittle and hard complex parts machining.In addition to the brittle and hard materials, this thesis made tentative explorationon the ultrasonic milling of metal material. Because of its helical-structure, the millingcutter’s vibration mode is totally different from the abrasive wheel, which leads to aspecific machining mechanism. Experiments show that, under certain conditionsultrasonic milling, compared with the traditional milling, has a smaller cutting force.For further research on ultrasonic milling mechanism, this thesis had built athree-dimension milling cutter using with Pro/E, constructed the cutter’s general edgecurve model, and made modal and harmonious response analysis of milling cutter byfinite element. The study provides a solid foundation for further optimization of thecutting tool’s parameters.