Research On Ultrasonic-Assisted Abrasive Jet Deburring Technology Of Components Used In Minimally Invasive Surgery

The surface quality of components used in minimally invasive surgical instruments is so high that finishing must be used to meet the requirements in the final process of machining.At present,the burrs of the components are widely distributed after CNC machining,which remain on the edges and holes of these parts and are difficult to remove.And the finishing work that depends on manual work usually leads to low efficiency and quality.In view of the auto-destruction and green deburring problem of these components,ultrasonic-assisted abrasive jet technology is used to explore a new deburring method for minimally invasive surgical instrument parts.The main research work carried out in the thesis is as follows:(1)An experimental device for ultrasonic-assisted abrasive jet deburring was designed.Based on the analysis of abrasive jet and ultrasonic-assisted machining principle,the abrasive jet system,ultrasonic assisting system,lifting mechanism and the fixture of components were selected and designed.In ultrasonic assisting module,the variable amplitude horn with nozzle tool head was successfully designed and measured,which realized the amplitude of about 30μm at the voltage of 20 kHz and provided experience for others with the technique of introducing ultrasonic assistance into abrasive jet machining.(2)A monitoring control system based on MFC and STM32 was designed and developed.Through the modules of electric control valve,flow and temperature sensors,the system mainly realized the functions of flow rate control,data signal monitoring and storage during processing.The system adopted the concept of modular design,and preliminarily built the framework of automatic operation of this equipment for the subsequent expansion of other functions.(3)Numerical simulation of the ultrasonic-assisted abrasive jet flow field was carried out.After analyzing the mechanism of ultrasonic turbulence enhancement,fluent software was used to respectively simulate the single abrasive jet and the abrasive jet with ultrasonic-assisted for comparing the flow field velocity distribution and turbulent kinetic energy distribution according to the simulation results.These helped analyze the characteristics and advantages of the ultrasonic-assisted abrasive jet and provide the theoretical basis for the subsequent experiments.(4)The experimental research of ultrasonic-assisted abrasive jet deburring was carried out.The optimal dispersion parameters of SiC abrasive were obtained by dispersion experiments.Single factor experiments were used to do research on the flow rate,the target distance,abrasive concentration and processing time during the machining process.The optimal experimental parameters of ultrasonicassisted abrasive processing were obtained by orthogonal experiments and verified by multiple tests.The experimental result shows that when the pump flow rate is 150L/h,the SiC abrasive volume fraction is 10%,the mixture pH is 9,the PVP-K30 volume fraction is 8%,the target distance is 10 mm,and the processing time is 60 s,the burrs of these components can be basically removed.Moreover,the machining effects of ultrasonic-assisted abrasive jet and single abrasive jet were analyzed by comparative experiments.And the result shows that ultrasonic-assisted abrasive jet has higher burr removal quality and the machining process is efficient and reliable.