Experimental Study On Electrical Discharge Machining Of Metal Matrix Composites By V-groove Electrode

With the development of industry,metal matrix composite is used more and more widely because of its special characteristics of light weight,high strength and low coefficient of thermal expansion.At present,the demand for the secondary processing of metal matrix composite materials is growing day by day.The commonly used processing methods are traditional machining methods and special machining methods(mainly including abrasive water jet machining,laser machining,laser-assisted micro machining,electrical discharge machining(EDM),electrochemical discharge machining,electrochemical machining,ultrasonic vibration machining,etc.).However,many research results show that there are some difficulties in machining metal matrix composite materials either by machining or by special machining methods.Taking EDM drilling as an example,it is difficult to avoid serious tool wear,even tool fracture and surface cracks after machining by using mechanical machining methods.In special machining methods,EDM is used to punch holes The main bottleneck lies in the non conductivity of ceramic particles and the difficulty of removing processing debris.In this paper,a V-groove electrode EDM method for metal matrix composites is proposed to solve the problem that it is difficult to discharge the debris.In this research method,V-groove structure,which is widely used in deep hole drilling,is ingeniously applied in the field of EDM to promote chip removal,and the high spindle speed is used to disturb the flow field in the machining area to improve the stability of discharge.First of all,this paper expounds the erosion mechanism and processing influencing factors of EDM metal matrix composite materials,and puts forward the basic principle of V-groove electrode EDM;secondly,the V-groove electrode is designed and manufactured,and the machine platform is refitted and built according to the experimental conditions of high spindle speed.The rotating spindle is mainly designed,analyzed and replaced to realize the processing conditions of high spindle speed;next,the flow field of V-groove electrode in EDM of metal matrix composites is modeled and simulated,the distribution of gap flow field and gap erosion particle is analyzed,and the chip removal advantage ofV-groove electrode is preliminarily determined;finally,the single factor experiment is conducted to investigate the spindle speed,flushing pressure,peak current,pulse width and duty cycle The effect of ratio and other factors on the machining efficiency of V-groove electrode in EDM of metal matrix composite materials is mainly studied in terms of material removal rate and relative loss rate.By comparing with circular electrode,it is found that under the same machining parameters,V-groove electrode can greatly promote the discharge of machining chips,thus improving the efficiency of EDM metal matrix composites and reducing the relative loss of tools.The material removal rate of V-groove electrode is about 30% higher than that of circular electrode,and the relative loss rate of tool electrode is about 15% lower than that of circular electrode.