Design And Experimental Research Of Rotary Ultrasonic Tool Holder

SiC ceramics have the characteristics of high hardness,low density,high temperature resistance and high thermal conductivity.It is widely used in the field of aerospace and other defense fields.At present,the most widely used in the processing is to use diamond grinding wheel to grind it.However,rapid tool wear,low machining efficiency and surface / subsurface damage are common problems in SiC ceramic grinding.The application of ultrasonic vibration assisted grinding method in machining hard and brittle materials represented by engineering ceramics has significant advantages in improving the surface quality of the workpiece,prolonging tool life,improving the machining efficiency and reducing the processing cost.However,the mature commercial ultrasonic assisted machine tools are mainly imported from abroad and the price is expensive.Although domestic universities have made many progress and achievements in the research and development of ultrasonic equipment,but they are mostly in the experimental state and have not been directly applied to the field processing.In view of this,in this paper,the rotary ultrasonic tool holder in the ultrasonic assisted machining system is taken as the research object.The ultrasonic vibration unit and the power transmission unit are mainly studied.The main work is as follows:(1)According to the application occasion and requirement of rotary ultrasonic tool holder,a design scheme of tool handle structure and half wavelength ultrasonic vibrator is established by using the sandwich piezoelectric transducer design theory and the design of rotary ultrasonic vibrator with axial longitudinal vibration.Using the finite element simulation software to optimize the structure size of the designed ultrasonic transducer,then the ultrasonic vibrator prototype is tested by the ultrasonic component analyzer.In view of the material and suspension length of the clamping tool,the influence of various factors on the resonant frequency of the ultrasonic oscillator is analyzed.(2)Based on the principle of electromagnetic induction effect of loosely coupling transformer,the electric energy transmission unit of the ultrasonic tool holder is designed.According to the different primary and secondary compensation circuits and combined with the structure and application characteristics of rotary ultrasonic shank,the best compensation mode is formulated and the circuit compensation effect is tested through experiments.Finally,a prototype of HSK ultrasonic vibration machining system based on loosely coupled transformer and contactless power transmission is built,and the resonance frequency and tool end amplitude of rotary ultrasonic tool holder are tested.(3)The surface integrity experiment of SiC ceramic with electroplated diamond grinding wheel was carried out.The surface roughness of different grinding parameters was measured and the surface morphology was observed after grinding.At last,analysis of the effect of ultrasonic vibration on the machined surface in the face grinding process by comparison with the surface roughness and surface morphology of the grinding surface.The surface roughness experiment of electroplated diamond wheel ultrasonic assisted grinding of SiC ceramics is carried out.The grinding force under different grinding parameters is measured and the surface roughness after grinding is compared with or without ultrasonic vibration.The influence of ultrasonic assisted grinding parameters on the grinding force and surface roughness is studied and the vibration processing performance of the rotary ultrasonic tool holder is verified.