H. Obara, N. Ishizu, T. Kawai, T. Ohsumi, Takuro Hayashi
In the present study, the accuracy of the finish cut for Wire EDM is analytically and experimentally investigated. In order to simulate the finish cut, the explosive force, electrostatic force and electromagnetic force are estimated based on the wire deflection. The simulated wire deflection on the finish cut is compared to the measured value. Problems associated with the finish cut that were revealed by the simulated results are described. The effect of electrostatic force on the cut wall straightness and countermeasures to prevent this effect on the finish cut are described. The results of the present study are as follows; 1) the explosive force of the finish cut decreased to 30-60% of the rough cut, depending on the skimmed depth, 2) the dielectric constant of the water in the gap decreases to 20-30% of the nominal value during the finish cutting, 3) the electrostatic force may cause irregular wire movement, and for thick work pieces may overcut at the corners, 4) the electrostatic force results in concave cut walls, and 5) the finish cutting in air is useful for decreasing the electrostatic force and obtaining good wall straightness.
{"title":"Simulation of Wire EDM (3rd Report)","authors":"H. Obara, N. Ishizu, T. Kawai, T. Ohsumi, Takuro Hayashi","doi":"10.2526/JSEME.34.30","DOIUrl":"https://doi.org/10.2526/JSEME.34.30","url":null,"abstract":"In the present study, the accuracy of the finish cut for Wire EDM is analytically and experimentally investigated. In order to simulate the finish cut, the explosive force, electrostatic force and electromagnetic force are estimated based on the wire deflection. The simulated wire deflection on the finish cut is compared to the measured value. Problems associated with the finish cut that were revealed by the simulated results are described. The effect of electrostatic force on the cut wall straightness and countermeasures to prevent this effect on the finish cut are described. The results of the present study are as follows; 1) the explosive force of the finish cut decreased to 30-60% of the rough cut, depending on the skimmed depth, 2) the dielectric constant of the water in the gap decreases to 20-30% of the nominal value during the finish cutting, 3) the electrostatic force may cause irregular wire movement, and for thick work pieces may overcut at the corners, 4) the electrostatic force results in concave cut walls, and 5) the finish cutting in air is useful for decreasing the electrostatic force and obtaining good wall straightness.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125290493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hidekazu Tsukahara, H. Minami, K. Masui, K. Demizu, T. Sone
Surface modification of titanium using EDM process was studied. To form a new titanium carbide (TiC) layer on the machined surface, finishing EDM process was examined. TiC layer with crack less surface was obtained in the relatively short discharge duration with low discharge current range under the electrode negative polarity.And the various effective improvements in machined surface such as hardness, tribological properties and corrosion resistance were obtained respectively.
{"title":"Surface Modification of Titanium using EDM Process","authors":"Hidekazu Tsukahara, H. Minami, K. Masui, K. Demizu, T. Sone","doi":"10.2526/JSEME.33.74_9","DOIUrl":"https://doi.org/10.2526/JSEME.33.74_9","url":null,"abstract":"Surface modification of titanium using EDM process was studied. To form a new titanium carbide (TiC) layer on the machined surface, finishing EDM process was examined. TiC layer with crack less surface was obtained in the relatively short discharge duration with low discharge current range under the electrode negative polarity.And the various effective improvements in machined surface such as hardness, tribological properties and corrosion resistance were obtained respectively.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116766482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we propose a microcutting method with a reduced machining force by applying an electrolytic passive film formation on the workpiece surface. This process realizes the machining of microstructure such as 10μm wide micro grooves which has been difficult to be machined by conventional cutting. A mirror surface which has the roughness 30nm Ry is also obtained by this method.
{"title":"Microcutting with Reduced Cutting Force by Electrolysis.","authors":"M. Nagata, K. Wakabayashi, M. Yamada, T. Masuzawa","doi":"10.2526/JSEME.33.74_24","DOIUrl":"https://doi.org/10.2526/JSEME.33.74_24","url":null,"abstract":"In this paper, we propose a microcutting method with a reduced machining force by applying an electrolytic passive film formation on the workpiece surface. This process realizes the machining of microstructure such as 10μm wide micro grooves which has been difficult to be machined by conventional cutting. A mirror surface which has the roughness 30nm Ry is also obtained by this method.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132444098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper reports on the improvement in the machining performance of quick response and higher speed in the linear motor servo-equipped Die-sinking EDM. The linear motor system allows the motor itself to move, so the travel distance measured by the linear scale is directly sent back to the motor. It enables a simpler control mechanism without the effect of backlash. Since the electrode is directly installed at the motor itself, the movement of both the electrode and the motor can be regarded as a one-piece body's movement. Because of these characteristics, even in the machining systems based on the voltage feedback of the electrical discharge gaps, an excellent follow-up and a quick response are possible as well as a higher and consistent accuracy at higher speed.
{"title":"Electrical Discharge Machining Performance of Linear Motor Equipped Die-Sinking EDM","authors":"Yuji Kaneko, H. Yamada, T. Toyonaga, K. Shoda","doi":"10.2526/JSEME.33.74_32","DOIUrl":"https://doi.org/10.2526/JSEME.33.74_32","url":null,"abstract":"This paper reports on the improvement in the machining performance of quick response and higher speed in the linear motor servo-equipped Die-sinking EDM. The linear motor system allows the motor itself to move, so the travel distance measured by the linear scale is directly sent back to the motor. It enables a simpler control mechanism without the effect of backlash. Since the electrode is directly installed at the motor itself, the movement of both the electrode and the motor can be regarded as a one-piece body's movement. Because of these characteristics, even in the machining systems based on the voltage feedback of the electrical discharge gaps, an excellent follow-up and a quick response are possible as well as a higher and consistent accuracy at higher speed.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114568899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recently, it was reported that a hard TiC layer could be made on the machined surface by EDM using a titanium electrode in kerosene and this technique was applicable to cutting tool such as throwaway tip or endmill. However, the layer is relatively thin and the surface roughness is not so small. Then, it is difficult to apply this method to a metal mold which needs glossy surface. In this study, a new method to form TiC layer by EDM for smaller surface roughness and thick layer is proposed, and the effects of machining conditions on characteristics of the layer are experimentally investigated. Furthermore, the wear resistance of EDMed surface was evaluated.Experimental analysis made it clear that a thick and smooth TiC layer could be generated on the machined surface by EDM using a titanium electrode in carbon powder mixed fluid. It was also pointed out that the hardness of modified surface became higher with increases of discharge duration or carbon powder concentration in the kerosene type machining fluid, and that the wear resistance of the layer was much larger than that of base material.
{"title":"Surface Modification by EDM with Carbon Powder Mixed Fluid using Titanium Electrode","authors":"A. Okada, Y. Uno, Hirao Kazuhisa, T. Takagi","doi":"10.2526/JSEME.33.73_31","DOIUrl":"https://doi.org/10.2526/JSEME.33.73_31","url":null,"abstract":"Recently, it was reported that a hard TiC layer could be made on the machined surface by EDM using a titanium electrode in kerosene and this technique was applicable to cutting tool such as throwaway tip or endmill. However, the layer is relatively thin and the surface roughness is not so small. Then, it is difficult to apply this method to a metal mold which needs glossy surface. In this study, a new method to form TiC layer by EDM for smaller surface roughness and thick layer is proposed, and the effects of machining conditions on characteristics of the layer are experimentally investigated. Furthermore, the wear resistance of EDMed surface was evaluated.Experimental analysis made it clear that a thick and smooth TiC layer could be generated on the machined surface by EDM using a titanium electrode in carbon powder mixed fluid. It was also pointed out that the hardness of modified surface became higher with increases of discharge duration or carbon powder concentration in the kerosene type machining fluid, and that the wear resistance of the layer was much larger than that of base material.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130910632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
At present, cold working die steel, SKD11, is commonly being used as a material for metal molds due to its superior wear and corrosion resistance properties. However, it is difficult to obtain die steel SKD11 with a mirror-finished surface during metal mold manufacturing, because of the coarse-grained carbides present in the base metal. In this study, laser surface modification with melting has been proposed to improve the surface finish of SKD11 as a new surface modification method. In this method, coarse-grained carbides can be decomposed by melting the surface layer using a laser beam. As a result, the carbides containing coarse grains in the surface layer can be completely decomposed into their elements by laser beam irradiation to the surface. Both the compositions and crystalline structure in the modified region are entirely uniform, and the laser irradiated material could be polished easily to obtain a mirror-finished surface using alumina as an abrasive. Moreover, the reflectivity of light from the laser irradiated surface after polishing is 15% higher than that from the surface of the as-received sample.
{"title":"Surface Modification of Cold Working Die Steel, SKD11, using Laser Irradiation","authors":"T. Tamura","doi":"10.2526/JSEME.33.73_23","DOIUrl":"https://doi.org/10.2526/JSEME.33.73_23","url":null,"abstract":"At present, cold working die steel, SKD11, is commonly being used as a material for metal molds due to its superior wear and corrosion resistance properties. However, it is difficult to obtain die steel SKD11 with a mirror-finished surface during metal mold manufacturing, because of the coarse-grained carbides present in the base metal. In this study, laser surface modification with melting has been proposed to improve the surface finish of SKD11 as a new surface modification method. In this method, coarse-grained carbides can be decomposed by melting the surface layer using a laser beam. As a result, the carbides containing coarse grains in the surface layer can be completely decomposed into their elements by laser beam irradiation to the surface. Both the compositions and crystalline structure in the modified region are entirely uniform, and the laser irradiated material could be polished easily to obtain a mirror-finished surface using alumina as an abrasive. Moreover, the reflectivity of light from the laser irradiated surface after polishing is 15% higher than that from the surface of the as-received sample.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124987562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This present paper investigates about accuracy of rough convex corner and convex corner R. Previous some reports proposed methods to improve corner and corner R accuracy of wire EDM. One method controls EDM conditions and other method modifies a program path at the corner and corner R, and 3rd method is a on-line system which detects wire deflection and corrects a contouring path. But 1st method has problems that the corner accuracy is insufficient and it lacks details to decide EDM parameters. Also 2nd method has a problem that the accuracy on top surface differs from that on middle cross section surface of a work piece. In addition 3rd method is only useful for special machines. In this paper we propose a combined power and path control method to improve the convex corner and corner R accuracy which is useful for ordinary operators. In the method, discharge power is adjusted so that the error of convex corner and corner R on the top or bottom surface of the work piece decreases within a desired value. The program path is corrected so as the residual error on the middle surface of the work piece to be 0.
{"title":"Fundamental Study of Accuracy of Wire EDM (2nd Report)","authors":"H. Obara, T. Kawai, T. Ohsumi","doi":"10.2526/JSEME.33.20","DOIUrl":"https://doi.org/10.2526/JSEME.33.20","url":null,"abstract":"This present paper investigates about accuracy of rough convex corner and convex corner R. Previous some reports proposed methods to improve corner and corner R accuracy of wire EDM. One method controls EDM conditions and other method modifies a program path at the corner and corner R, and 3rd method is a on-line system which detects wire deflection and corrects a contouring path. But 1st method has problems that the corner accuracy is insufficient and it lacks details to decide EDM parameters. Also 2nd method has a problem that the accuracy on top surface differs from that on middle cross section surface of a work piece. In addition 3rd method is only useful for special machines. In this paper we propose a combined power and path control method to improve the convex corner and corner R accuracy which is useful for ordinary operators. In the method, discharge power is adjusted so that the error of convex corner and corner R on the top or bottom surface of the work piece decreases within a desired value. The program path is corrected so as the residual error on the middle surface of the work piece to be 0.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131591387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes that the material removal rate of the electrical discharge machining (EDM) is higher when deionized water is used as the working fluid than when EDM working oil is used. Influences of the electrode surface temperature, discharge energy distribution, carbon precipitation on anode surface, electrolysis, and reaction of oxidation on the difference in material removal rate between machining in water and in oil were investigated experimentally. It was concluded that the higher material removal rate using the deionized water is principally attributed to the oxidation of electrode materials with the oxygen generated through dissociation of water caused by the arc discharge.
{"title":"Study on Material Removal Rate of EDM in Deionized Water","authors":"Zhanbo Yu, M. Kunieda","doi":"10.2526/JSEME.33.28","DOIUrl":"https://doi.org/10.2526/JSEME.33.28","url":null,"abstract":"This paper describes that the material removal rate of the electrical discharge machining (EDM) is higher when deionized water is used as the working fluid than when EDM working oil is used. Influences of the electrode surface temperature, discharge energy distribution, carbon precipitation on anode surface, electrolysis, and reaction of oxidation on the difference in material removal rate between machining in water and in oil were investigated experimentally. It was concluded that the higher material removal rate using the deionized water is principally attributed to the oxidation of electrode materials with the oxygen generated through dissociation of water caused by the arc discharge.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116099573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Monocrystalline silicon is one of the most important materials in the semiconductor industry because of its many excellent properties as a semiconductor. In the manufacturing process of silicon wafers, inner diameter (ID) blade and multi wire saw have conventionally been used for slicing silicon ingots. However, some problems in efficiency, accuracy, slurry treatment and contamination are experienced when applying this method to largescale wafers of 12 or 16 inch diameter expected to be used in the near future. Thus, the improvement of conventional methods or a new slicing method is strongly required. In this study, the possibility of slicing a silicon ingot by wire EDM was discussed and the machining properties were experimentally investigated. A silicon wafer used as substratum for epitaxial film growth has low resistivity in the order of 0.01Ω·cm, which makes it possible to cut silicon ingots by wire EDM. It was clarified that the new wire EDM has potential for application as a new slicing method, and that the surface roughness using this method is as small as that using the conventional multi wire saw method. Moreover, it was pointed out that the contamination due to the adhesion and diffusion of wire electrode material into the machined surface can be reduced by wire EDM under the condition of low current and long discharge duration.
{"title":"A New Slicing Method of Monocrystalline Silicon Ingot by Wire EDM","authors":"A. Okada, Y. Uno, Y. Okamoto, H. Itoh, T. Hirano","doi":"10.2526/JSEME.34.14","DOIUrl":"https://doi.org/10.2526/JSEME.34.14","url":null,"abstract":"Monocrystalline silicon is one of the most important materials in the semiconductor industry because of its many excellent properties as a semiconductor. In the manufacturing process of silicon wafers, inner diameter (ID) blade and multi wire saw have conventionally been used for slicing silicon ingots. However, some problems in efficiency, accuracy, slurry treatment and contamination are experienced when applying this method to largescale wafers of 12 or 16 inch diameter expected to be used in the near future. Thus, the improvement of conventional methods or a new slicing method is strongly required. In this study, the possibility of slicing a silicon ingot by wire EDM was discussed and the machining properties were experimentally investigated. A silicon wafer used as substratum for epitaxial film growth has low resistivity in the order of 0.01Ω·cm, which makes it possible to cut silicon ingots by wire EDM. It was clarified that the new wire EDM has potential for application as a new slicing method, and that the surface roughness using this method is as small as that using the conventional multi wire saw method. Moreover, it was pointed out that the contamination due to the adhesion and diffusion of wire electrode material into the machined surface can be reduced by wire EDM under the condition of low current and long discharge duration.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116428462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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