Research On The Forming Mechanism And Experiment Of Rotating Ultrasonic Compound Generating Electro-processing

The rapid development of science and technology has put forward new and higher requirements for the machinery manufacturing industry.The application of various difficult-to-machine materials and special-shaped surface parts is more and more extensive.Because of the advantages of non-material hardness,small processing force and low tool wear(or none),various new special processing technologies have been paid special attention to,and have been more and more used.Ultrasound and its composite electro-heating have been widely used in the processing of difficult-to-machine materials and special-shaped parts.Ultrasound grinding,Ultrasound-assisted milling-Ultrasound-assisted drilling and other processing methods utilize ultrasound frequency vibration effect to reduce cutting force and heat,improve processing efficiency and stabilize processing accuracy.In this paper,a new processing method-rotating ultrasonic composite generation electro-machining is proposed.It is attempted to combine the ultrasonic effect with mechanical cutting,electrolysis and discharging to process various difficult-to-machine materials and profiles accurately and efficiently.This paper focuses on the processing mechanism,device design and related experimental research of this new processing method.According to indentation fracture principle,the material removal rate model of rotary ultrasonic machining is established firstly,then the material removal efficiency model of pulse electrochemical machining of hard and tough materials under ultrasonic vibration is established according to Faraday's electrolysis law,and finally the material removal rate of rotary ultrasonic composite evolution is established according to the interaction relationship between rotary ultrasound and pulse electrolysis.The main parameters affecting the machining efficiency are pulse voltage U,machining clearance,ultrasonic amplitude A and generating feed speed V.The forming error(machining accuracy)of generating process is mainly caused by the discrepancy between trajectory error and machining clearance.The overall scheme of rotary ultrasonic composite generation electro-machining system is analyzed and designed.A rotary ultrasonic vibration device is constructed by combining AC motor,frequency converter and piezoelectric ultrasonic oscillator.The piezoelectric ultrasonic oscillator is composed of two PZT-8(transmitting)piezoelectric ceramic plates and step-type horn.The size of piezoelectric transducer and horn is calculated and ANSYS is carried out.Analysis and optimization;design a radial ultrasonic vibration device,which consists of two piezoelectric ceramic transducers to provide ultrasonic frequency vibration,and realize two-dimensional ultrasonic vibration;construct and improve the rotary ultrasonic composite generation electrical processing system,select the processing power supply and voltage and current measuring device,use laser displacement sensor to measure the ultrasonic vibration amplitude,the spindle amplitude can be continuously adjusted in 0-20 micron.The amplitude of the radial ultrasonic vibration device can reach 7 microns,which verifies the accuracy of the design and finite element analysis.By using the designed rotating ultrasonic composite generating electrical processing system.rotating ultrasonic speed is 0 rmp-5000rmp,and axial ultrasonic amplitude is 0-8 micron,the single mechanical drilling of PZT piezoelectric ceramics and the contrast experiment of hole processing after adding ultrasonic effect are carried out.The rotating ultrasonic processing efficiency is higher,and with the increase of ultrasonic amplitude,the processing efficiency increases;the mechanical grinding and rotating of high-speed steel tool materials are carried out.Contrastive experiments of ultrasonic and rotary ultrasonic composite machining showed that 5%NaN03 electrolyte,ultrasonic amplitude of 16 microns,pulse voltage frequency of 5 kHz,amplitude of 2V-6V,duty cycle of 50%.The experiment proved that rotary ultrasonic composite machining had the highest efficiency,and the greater the voltage amplitude,the higher the processing efficiency.However,when the voltage reached 6V,the electrolytic stray corrosion and spark ablation were serious,and the voltage amplitude of 4V was more close.Comparing rotating ultrasonic machining with rotating ultrasonic compound electroforming forming test for high speed steel and cemented carbide(YT15),the phenomenon of intermediate bump appears when the radial feed speed is 15mm/min and the plane is formed.Reducing the feed speed and additional electrolysis can effectively reduce the bump,while the additional electrolysis can effectively reduce the surface roughness when the side is formed.In the process of groove generation EDM,the phenomenon of spark discharge is serious,difficult to process and the processing process is not stable.Adding radial ultrasonic vibration(two-dimensional ultrasound)to groove generation EDM can effectively reduce the phenomenon of spark discharge,improve the processing efficiency and process stability.This paper summarizes the design and experimental results of the rotary ultrasonic composite generation electrical processing system,demonstrates the feasibility,technical advantages and application prospects of the rotary ultrasonic composite generation electrical processing method,and finally analyses the problems existing in the existing processing system and test,puts forward further improvement and improvement measures,and puts forward ideas and prospects for the follow-up test and research.