Study On Technology Of Rotary Ultrasonic Longitudinal Vibration Drilling For Micro Holes

The rotary ultrasonic longitudinal vibration drilling technology is a new type of machining method for micro holes, which is combined rotary cutting movement of micro drill with ultrasonic longitudinal vibration. It shows that the new method changes the cutting mechanism in the course of drill-entry and the conventional continuous cutting process is transformed into a pulsed discontinuous cutting process by using vibration drilling. The rotary ultrasonic longitudinal vibration drilling technology has more excellent technology effect than common methods in micro holes precision machining areas, can remarkably improve machining quality and efficiency. Some research has been carried out on rotary ultrasonic longitudinal vibration drilling technology in order to solve the difficulties that is the precision machining of micro holes in some materials hard to be machined.Firstly, based on high frequency vibration cutting theories, a rotary ultrasonic vibration Longitudinal drilling device for micro holes has been developed , which is simple and transplantable in structure. The device includes four modules, which are ultrasonic generator, half wave vibration system, rotary joint subassembly and tool system. After developing thedevice, we go on to do integration debug and performance measure. Debug work is concerned with individual debug of each of module and integrative debug of the device. Performance measure is concerned with vibration frequency and amplitude of half wave acoustics system.Secondly, the dynamic behavior of micro drill is deeply studied on using modal analysis, transient dynamic analysis and static analysis technology in finite element software. The drill-entry characteristic difference between conventional drilling and rotary ultrasonic vibration drilling is compared. Based on dynamic model of micro drill, The effects of vibration parameters and cutting parameters on drill-entry spotting accuracy is analyzed by using mathematics computing software. Above-mentioned analyses in this paper lay a theoretical basis for improving performance of the device and doing technologic experiments of vibration drilling.Finally, based on machining center named UCP710, preliminary experiments between conventional drilling and vibration drilling are carried out by using developed rotary ultrasonic vibration drilling device, the device works well and machining quality of micro holes is remarkably improved, such as reducing thrust and quality of the heat, eliminating or restraining cutting vibration caused by drilling and improving drill life.Though preliminary experiments show the vibration drilling has excellent technological effects, to apply the new method to practical industrial production, however, a large number ofexperiments have to carried out for further optimization of drilling parameters for all kinds of different materials.