Impact Analysis of Electrode Material on Electrical Discharge Machining Polycrystalline Diamond Processing

2013 ◽  
Vol 441 ◽  
pp. 36-39
Author(s):  
Yun Hai Jia

The electrode material plays a very important role in the electric discharge machining, affects the electrical discharge machining efficiency and machining surface quality. Experiment testing and materials analysis as the primary method, affect layer thickness and workpiece surface roughness value as evaluation indexes. PCD cutting tool samples were electrical discharge machined using copper electrodes and graphite electrodes respectively. After machining, the PCD cutting tool samples' surfaces were analyzed by X ray diffraction, the surfaces appearances were observed under the scanning electron microscope, and the surface roughness values were measured by roughness measuring instrument. PCD samples' surface effect layer thickness values and surface roughness values, affect layer distribution structure was statically analyzed in typical EDM process conditions with different electrode materials. Summary electrode material effect on PCD cutting tools in EDM processing. Provides an important experimental basis for designing technics of precision and highly efficient electrical discharge machining PCD cutting tools.

2011 ◽  
Vol 399-401 ◽  
pp. 1667-1671 ◽  
Author(s):  
Yun Hai Jia

The electrode material is playing the very important role in the electrical discharge machining. Two kinds of electrode materials common used in EDM are compared and analyses similarities and differences in structure and physical characteristics. Combined with PcBN tool machining tests, from the electric discharge machining efficiency, electrode wear, tool surface quality, tool surface degenerating layer, machining results are in analysis and comparison, and then different electrode materials machining technics in electrical discharge machining process are summarized. Through the cutting tool electric discharge machining experiments, we can know that the graphite electrode easy to take shape, suits in the complex edge's cutting tool electric discharge machining, under the same electric discharge machining parameter condition, its processing efficiency must be higher than the copper electrode, but the electrode loses, the cutting tool surface quality and affect layer thickness are to be worse than the copper electrode.


2011 ◽  
Vol 268-270 ◽  
pp. 309-315 ◽  
Author(s):  
Yun Hai Jia ◽  
Jian Gang Li ◽  
Xue Jun Lu

The Samples of Polycrystalline Diamond (PCD) Cutting Tool Were Machined by Adjusting the Main Parameters of Electrical Discharge Machining (EDM). after the Machining, the Phases Were Analyzed by X-Ray Diffraction Analyzer and the Surface Layer Microstructure Were Observed by Scanning Electronic Microscope. the Fundamental Component of Machined PCD Cutting Tool Affected Layer Was Obtained and the Reason of Bring Affected Layer Was Analyzed. the Relationship Curves between Pulse Width, Working Electric Current and Depth Affected Layer, Surface Roughness Were Summarized. the Relationship between PCD Cutting Tools that Was Machined by EDM and Cutting Tool Flank Width, Workpiece Surface Roughness Were Analyed.The Results Showed that to Adjust Electical Discharge Machining Parameter, such as Pulse Width and Machining Electric Currents, Can Reduce the Depth of Affect Layer and Extend the Service Life of PCD Cutting Tool.These Researches Provide Valuable Test Reference for Drawing up Electrical Discharge Machining Technics of PCD Cutting Tool and Cutting Tool’s Life.


Author(s):  
Guisen Wang ◽  
Fuzhu Han ◽  
Liang Zhu

Abstract White layer and residual stress are the main reasons for the decrease in fatigue life of electrical discharge machined samples. Therefore, it is important to research the evolution of the white layer and residual stress in electrical discharge machining and explain the influence mechanism of machining parameters on them. In this study, the surface topography, white layer thickness, and residual stress of electrical discharge machined samples under different processing parameters were evaluated. The results indicated that surface roughness, white layer thickness, and residual stress increased as the discharge current (I) and pulse-on time (ton) increased. However, when the ton was short, the effect of I (≤ 9.8 A) on surface roughness is not very obvious. When the discharge energy is similar, surface roughness is high under high I conditions. When the discharge energy is similar and low, the average thickness of the white layer is thin under the low I. The effect of I on surface residual stress was greater than that of the ton. The I and ton affect the white layer and residual stress by affecting the amount of melting and removal of the materials. These results were demonstrated that the input process of discharge energy has an important influence on residual stress and the white layer. Therefore, under the premise of ensuring the processing requirements, they can be controlled by selecting the appropriate combination of the ton and I to improve the fatigue life of the workpiece.


Author(s):  
M Sreenivasa Rao ◽  
N Venkaiah

Nickel-based alloys are finding a wide range of applications due to their superior properties of maintaining hardness at elevated temperatures, low thermal conductivity and resistance to corrosion. These materials are used in aircraft, power-generation turbines, rocket engines, automobiles, nuclear power and chemical processing plants. Machining of such alloys is difficult using conventional processes. Wire-cut electrical discharge machining is one of the advanced machining processes, which can cut any electrically conductive material irrespective of its hardness. One of the major disadvantages of this process is formation of recast layer as it affects the properties of the machined surfaces. In this study, experimental investigation has been carried out to study the effect of wire-cut electrical discharge machining process parameters on micro-hardness, surface roughness and recast layer while machining Inconel-690 material. Interestingly, hardness of the machined surface was found to be lower than that of the bulk material. The micro-hardness and recast layer thickness are inversely related to the variation of process parameters. Recast layer thickness, surface roughness and hardness of the wire-cut electrical discharge machined surfaces of Inconel-690 are found to be in the range of 10–50 µm, 0.276–3.253 µm and 122–171 HV, respectively, for different conditions. The research findings and the data generated for the first time on hardness and recast layer thickness for Inconel-690 will be useful to the industry.


Author(s):  
Yakup Yildiz ◽  
Murali M Sundaram ◽  
Kamlakar P Rajurkar ◽  
Ahmet Altintas

Electrical discharge machining (EDM) is an extensively used method in the machining of electrically conductive materials. Recast or white layer formation is undesirable, but inevitable, result of EDM and needs to be understood and accurately determined to efficiently perform post-treatment processes for removing the recast layer caused by EDM process. In this study, recast layer thickness and surface roughness data obtained from experimental study were analyzed and a correlation between these two parameters has been established. Image-processing technique has been used for obtaining of recast layer thickness data. It was observed that the correlation between recast layer thickness and surface roughness increases remarkably with the increase of working current and pulse time. The correlation obtained in this study has the potential to predict the recast layer thickness on spark-eroded surfaces from simple surface roughness values instead of using the prevailing time-consuming and tedious etching and polishing method. The possible approximation of the recast layer thickness using a thermal model is also discussed.


2011 ◽  
Vol 120 ◽  
pp. 311-315 ◽  
Author(s):  
Yun Hai Jia

The samples of Polycrystalline cubic boron nitride (PcBN) cutting tool were machined by adjusting the main parameters of electrical discharge machining (EDM). After the machining, the phases were analyzed by X-ray diffraction analyzer and the surface layer microstructure was observed by scanning electronic microscope. The fundamental component of machined PcBN cutting tool affected layer was obtained and the reason of begetting affected layer was analyzed. The relationship curves between pulse width, working electric current and thickness of affected layer, blade surface roughness were summarized. The relationship between PcBN cutting tool’s life that was machined by EDM and cutting tool flank width, workpiece surface roughness were analyzed. The results showed that to adjust electrical discharge machining parameters, such as decreasing pulse width or machining electric currents, can reduce the thickness of affect layer, improve blade surface roughness and extend the service life of PcBN cutting tool. These researches provide valuable test reference for drawing up electrical discharge machining technics of PcBN cutting tool and forecasting cutting tool’s life.


2012 ◽  
Vol 472-475 ◽  
pp. 2537-2541
Author(s):  
Fang Jiang ◽  
Wen Min Liao

Based on the electrode finishing technique in electrical discharge machining (EDM), a new method is proposed in the article to fabricate minitype cutting tool efficiently. The research on the techniques to attain the minitype cutting tool was based on analyzing the feature of EDM on minitype cutter. The process of fabrication for minitype cutting tool is determined, and the minitype grooving tools with the characteristic sizes of 70 μm were made of two types of materials. This fabrication method proved to be applicable to high efficiency fabrication of minitype cutting tool. The factors affecting precision of minitype cutter were analyzed, the causes for worse shape precision and surface roughness were described specifically, and the suggestions to improve the machining quality were proposed.


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