Mechanism Study And Process Optimization Of Ultrasonic Vibration-Assisted Powder Mixed EDM Of TiN Ceramics

Titanium nitride(TiN)ceramic materials are widely used in aerospace,surface coating,decoration and military industries due to their outstanding performances of high strength,high melting point,and good conductivity.When using traditional machining methods,cutting tools will be severely consumed,resulting in high processing costs and low processing efficiency.The strength and hardness of the processed object will not affect electrical discharge machining(EDM),so EDM has great advantages for the processing of conductive engineering ceramic materials.However,conventional EDM has the shortcomings of low machining efficiency and poor surface quality,and the instantaneous temperature difference generated after discharge can damage the material surface,even leading to material fragmentation in severe cases.Therefore,studying a high-efficiency,high-quality,low-cost EDM technology and mechanism for TiN ceramic materials has important theoretical significance and practical application value.Based on the physical performances of TiN ceramic materials,the mechanism of TiN removal in ultrasonic vibration-assisted powder mixed EDM was analyzed,and the influence of mixed powder particles and tool electrode additional ultrasonic vibration on the performance of EDM was studied.The analysis shows that ultrasonic vibration of electrodes and the addition of mixed powder particles are beneficial to improving the efficiency and quality of electrical discharge machining of TiN ceramic materials.Establish an experimental platform for ultrasonic vibration assisted powder mixed EDM,including the design and construction of ultrasonic vibration system and powder mixed particle circulation system.The performance of the two parts was tested,the modal and harmonic response analysis of the ultrasonic-vibration spindle were performed,and the finished product was tested using an amplitude measuring instrument and impedance analyzer.The flow field simulation in a dielectric tank for the powder mixing particle circulation system was conducted,and the results showed that both parts met the experimental requirements of this topic.Simulate and verify the theoretical analysis,and analyze the gap flow field during discharge based on finite element method simulation.The effect of ultrasonic vibration of tool electrodes on the gap flow field was studied.The trajectory of debris and mixed particles during inter electrode erosion was tracked using a discrete phase model.The results showed that the ultrasonic vibration of the tool electrode accelerated the flow velocity of the gap flow field,greatly improving the removal efficiency of debris;moreover,the mixed powder particles can impact the workpiece surface through vibration,achieving certain material removal.Single factor experiments were conducted to analyze the effects of ultrasonic amplitude,powder mixing concentration,pulse width,and pulse interval on machining performance evaluation indicators.The experimental results show that as the ultrasonic amplitude increases,the material removal rate(MRR)continues to increase,the surface roughness first decreases and then increases,and the relative tool weal ratio(RTWR)first increases and then decreases;As the concentration of mixed powder particles increases,MRR first increases and then decreases,surface roughness first decreases and then increases,and RTWR first increases and then decreases;As the pulse width increases,MRR first increases and then decreases,resulting in an increase in surface roughness and a decrease in RTWR;As the pulse interval increases,MRR first increases and then decreases,surface roughness gradually decreases,and RTWR first decreases and then increases.Based on the response surface method,the process optimization of ultrasonic vibration assisted powder mixed EDM of TiN ceramic materials was carried out.Through comparative experiments,it was proved that the machining performance of ultrasonic vibration assisted powder mixed EDM was very excellent,providing relevant theoretical data and reference methods for the engineering application of ultrasonic vibration assisted powder mixed EDM of conductive ceramic materials.