Experimental Study Of EDM-induced Ablation Turning On TC4with Function Electrode

The traditional EDM has low erosion efficient and is subjected to the influence of pulse powerenergy output and other factors. As to the processing problems, a new method named EDM-inducedablation turning is put forward which use the function electrode and put into application of TC4titanium turning.According to principle of the EDM-induced ablation turning with function-electrode, thefunction electrode is designed and manufactured, and the whole processing system is also set up.The mechanism of the EDM-induced ablation turning TC4with function electrode is analyzed whichbasis on the workpiece surface, electrode end surface morphology and discharge waveform. Theresults show that the machining surface has a lot of micro cracks, and the oxygen could through microcracks into the substrate during machining process to burn deeply. The technological tests are carriedout on TC4by the EDM-induced ablation turning with function electrode and the influence law of theelectric parameters and non-electric parameters on the machining efficiency, the quality of workpieceand the electrode relative wear rate are studied. The study show that machining efficiency and theoxidation layer thickness increase with increase of the pulse width, low voltage electric current andthe oxygen pressure, but reduce with the increase of workpiece speed gradually. And the electroderelative wear rate has a contrast law. The contrast test is carried out between the EDM-inducedablation turning with function electrode and conventional EDM on TC4by using the optimalparameters. Results show that the machining efficiency of the EDM-induced ablation turning withfunction electrode is as high as2579.4mm3/min on the normal polarity, which is43.3times that of theconventional EDM, and the former has obvious polarity effect and is suitable for the positive polaritymachining. And the workpiece surface is finished by diminishing the energy, which the averageefficiency is20.4times that of conventional EDM turning with similar surface quality condition. Theworkpiece surface is strengthened by TiN which processed by the EDM-induced ablation turning withfunction electrode. The micro-hardness of strengthened surface is2.5times that of the workpiecesurface processed by the park-induced combustion turning with function electrode, and the surfaceroughness value is far less than the latter.