Research On Electrode Wear And Prediction In Ultrasonic Micro-EDM Machining

With the development of multi-field assisted EDM technology,ultrasonic assisted EDM has been widely used in the field of micro-hole machining.The specific method is to apply ultrasonic motion to the electrode to make the electrode produce high frequency agitation effect on the working liquid in the hole to improve the flow rate of the working liquid in the hole.Compared with the traditional electrode rotating motion,the ultrasonic assisted EDM micro-hole machining has the advantages of fast processing efficiency,high surface quality and small electrode wear,but with the progress of processing,the continuous accumulation of electrode wear will still lead to the decline of the size and shape accuracy of the micro-hole.Therefore,it is of great significance to quantitatively analyze the rule of electrode wear in ultrasonic assisted EDM micro-hole machining and establish a prediction model for electrode wear,not only to ensure the machining quality of single micro-hole,but also to ensure the uniformity of pore size of micro-hole group.Therefore,the main research and work of this paper are as follows:In order to verify the advantages of ultrasonic translational movement of electrode from the perspective of flow velocity,a simulation model of gap flow field in EDM micro-hole machining process without flapping was established,and the distribution and difference of gap flow field in the process of ultrasonic translational movement of electrode and common rotary movement were analyzed and summarized.The effects of ultrasonic vibration frequency,ultrasonic vibration amplitude,electrode speed and machining depth on the flow rate of working liquid were investigated.In order to simulate more real working conditions,a simulation model of external flushing was established,and the influence law of flushing velocity on medium fluid velocity was obtained.Range in order to obtain a suitable processing parameter setting,this paper has carried out the TR pulse power supply mode of ultrasonic assisted edm small hole machining single factor experiment,studies the TR pulse power and ultrasonic vibration parameters on electrode wear,the processing time,discharge gap and the influence law of orifice burrs,found a reasonable parameter Settings can gain better processing performance.At the same time,orthogonal experiments were carried out,aiming at four different processing indexes,and the significant degree of influence of experimental parameters on the four processing indexes were obtained respectively.In order to explore the influence of machining parameters on electrode wear,an experiment of ultrasonic assisted EDM micro-hole machining electrode wear was carried out in this paper.The influence rules of electrode diameter and workpiece thickness on electrode wear and size of electrode wear area were obtained.In order to verify the advantages of ultrasonic translational movement of the electrode from the perspective of electrode wear,a comparative experiment was carried out on the rotating movement of the electrode.The results show that the ultrasonic translational movement of the electrode improves the electrode wear obviously compared with the rotating movement,especially when the depth of the tiny hole is relatively large.In order to predict and compensate the electrode wear,a neural network model for predicting the electrode wear in micro-hole EDM machining was established based on the electrode diameter,workpiece thickness and number of machining holes,and a verification experiment was carried out using the data obtained from the model.Through measurement,the consistency of the outlet diameter of the micro-hole is improved.