The Experimental Study On Metal-bonded Fine-grained Diamond Wheels Dressed By Electrical Discharge Machining

This thesis focused on experimental study of metal-bond fine-grained diamondgrinding wheels by electric discharge machining (EDM) dressing. As well known,metal-bond diamond grinding is difficult to be dressed by conventional methods.Based on this background, the EDM method is used to dress metal-bondedfine-grained diamond grinding wheels in this thesis. EDM，a typical non-conventionalprocessing, is applied to the field of wheels dressing. The main research work is asfollows:(1) The EDM process and its mechanism were introduced. Some factors thataffect the EDM were analyzed, and the various factors affecting the discharge erosionwere explained. From the perspective of the EDM principle, the method of dressinggrinding wheels and its principle by EDM were described(2) Layout of experiment which used in EDM dressing of metal-bondedfine-grained diamond grinding wheels was designed, and the measurementequipments were briefly introduced. Experimental procedures and Experiment set-upwere elaborated; the experimental apparatus used in experiment was designed.(3) The experiment results were analyzed; the effect of the discharge parameters(the pulse voltage, the pulse peak current, and the pulse duty factor) on the dischargegap was studied; the effect regularity on efficiency of EDM dressing and grindingwheel surface topography was also summarized.(4) The dressed grinding wheels were used in grinding of J05cemented carbide,and the surfaces of the workpiece were measured. The correctness of EDM dressingmethod was conluded.The experimental results show that the spark discharge gap increases withincreasing the pulse duty factor and the pulse voltage, but increasing of the pulse peakcurrent has little effect on the discharge gap. Seperately increasing the duty factor orthe pulse voltage or pulse peak current could accelerate the rate of erosion, andimprove dressing efficiency. But the impact of increasing the duty factor of pulse wasmuch greater than that of the pulse voltage and current. Increased the duty factor orthe peak current or pulse voltage would generate worse topography on the surface ofof grinding wheel. The impact of increasing the duty factor was more obvious thanthat of increasing the pulse current or pulse voltage. According to experimental results, bigger discharge parameters was adopted to increase the drssing speed in therough dressing, and smaller dicscharge parameters to improve the surface morphologyof the grinding wheels in the finishing dressing.