This paper describes the technical merits of CO2 laser welding of titanium using a simple shielding system. The results of CO2 laser welding for titanium plates showed that excellent mechanical properties were obtained without after-shielding. From the thermal analysis during the laser welding process, it was determined that the temperature of both the welding zone and the heat-affected zone rose rapidly and then fell rapidly. Thus, atmospheric contamination (i. e, oxidation and nitriding) during laser welding was less than that during TIG (tungsten inert gas) arc welding.
{"title":"CO2 Laser Welding of Titanium.","authors":"H. Hagino, S. Noguchi, K. Masui","doi":"10.2526/JSEME.34.77_8","DOIUrl":"https://doi.org/10.2526/JSEME.34.77_8","url":null,"abstract":"This paper describes the technical merits of CO2 laser welding of titanium using a simple shielding system. The results of CO2 laser welding for titanium plates showed that excellent mechanical properties were obtained without after-shielding. From the thermal analysis during the laser welding process, it was determined that the temperature of both the welding zone and the heat-affected zone rose rapidly and then fell rapidly. Thus, atmospheric contamination (i. e, oxidation and nitriding) during laser welding was less than that during TIG (tungsten inert gas) arc welding.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124470391","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 study, the explosive load acting on the wire surface generated by discharge on the rough cut and the finish cut of wire EDM is investigated. The hydrodynamic explosion process in the water-filled gap is numerically analyzed using adiabatic bubble expansion model, and the impulsive load of each discharge acting on the wire surface is calculated. The distribution function of the discharge number on the wire surface is derived and the total load acting on the wire generated by continuous discharges is estimated. Wire deflection caused by the total load is compared with the experimentally obtained wire deflection and also with the wire deflection derived from the simple model, assuming that the impulsive load of each discharge is constant and acts normally on the wire surface. Results show that; 1) the impulsive load vector on the wire surface of each discharge is not normal to the wire surface, 2) the value of impulsive load by each discharge depends on the slammed depth and the location on the wire surface and 3) the results of analysis are able to explain the influence of the skimmed depth on the wire deflection of the finish cut and the rough cut.
{"title":"Analysis of Explosive Load on Wire Generated by Discharge of Wire EDM","authors":"M. Nakase, H. Obara, T. Ohsumi, M. Hatano","doi":"10.2526/JSEME.34.77_22","DOIUrl":"https://doi.org/10.2526/JSEME.34.77_22","url":null,"abstract":"In this study, the explosive load acting on the wire surface generated by discharge on the rough cut and the finish cut of wire EDM is investigated. The hydrodynamic explosion process in the water-filled gap is numerically analyzed using adiabatic bubble expansion model, and the impulsive load of each discharge acting on the wire surface is calculated. The distribution function of the discharge number on the wire surface is derived and the total load acting on the wire generated by continuous discharges is estimated. Wire deflection caused by the total load is compared with the experimentally obtained wire deflection and also with the wire deflection derived from the simple model, assuming that the impulsive load of each discharge is constant and acts normally on the wire surface. Results show that; 1) the impulsive load vector on the wire surface of each discharge is not normal to the wire surface, 2) the value of impulsive load by each discharge depends on the slammed depth and the location on the wire surface and 3) the results of analysis are able to explain the influence of the skimmed depth on the wire deflection of the finish cut and the rough cut.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133079252","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 a control method to improve the accuracy of a concave corner with small radius R on the rough cut of wire EDM. A well-known off-time (pulse interval time) control method has an advantage in terms of corner precision but it takes a long time to cut the corner. In this paper, methods to reduce the machining time of the off-time control method are discussed. The off-time control method is combined with the overcut method, the servo voltage control method and the simple path modification method. The proposed method is found to be useful for improving the corner accuracy and reducing the machining time. The machining time was decreased from 90 to 28 seconds, and it was shorter than 34 seconds of the dwell over cut method proposed in a previous study. The residual error of the corner shape was decreased to 15μm. The procedure and expressions used to calculate the control values are described.
{"title":"ワイヤ放電加工の加工精度に関する基礎的研究(第5報)休止時間制御を用いた小円弧凹コーナR荒加工の加工時間短縮方法","authors":"小原 治樹, 大竹 剛, 今井 渉","doi":"10.2526/JSEME.34.77_15","DOIUrl":"https://doi.org/10.2526/JSEME.34.77_15","url":null,"abstract":"This paper describes a control method to improve the accuracy of a concave corner with small radius R on the rough cut of wire EDM. A well-known off-time (pulse interval time) control method has an advantage in terms of corner precision but it takes a long time to cut the corner. In this paper, methods to reduce the machining time of the off-time control method are discussed. The off-time control method is combined with the overcut method, the servo voltage control method and the simple path modification method. The proposed method is found to be useful for improving the corner accuracy and reducing the machining time. The machining time was decreased from 90 to 28 seconds, and it was shorter than 34 seconds of the dwell over cut method proposed in a previous study. The residual error of the corner shape was decreased to 15μm. The procedure and expressions used to calculate the control values are described.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130556351","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 order to further improve the machining accuracy and machining speed of electrical discharge machining (EDMing), it is necessary to understand the gap condition during the EDMing process. In this paper, a new method of using ultrasonic waves to measure the gap condition is proposed. First, the possibility that the change in the quantity of bubbles existing in the gap between the electrode and the workpiece could be detected as a change in the attenuation factor of ultrasonic waves is confirmed through a fundamental experiment of the proposed detection method. Second, the method is applied to an actual EDMing process with several machining settings. From these experiments, the dissimilarity of the gap conditions under several EDMing processes is clarified and the fact that the gap is filled with bubbles for most of the machining period is confirmed. Third, a comparative experiment is conducted to investigate the influence of the amount of bubbles in the gap on machining efficiency. As a result of the experiment, it is ascertained that machining with a small amount of bubbles has higher efficiency than machining with a large amount of bubbles. These results provide useful information for constructing the most suitable EDMing control system for improving machining performance.
{"title":"Observation of Quantity of Bubbles in Electrical Discharge Machining Gap","authors":"M. Hiroi, Y. Imai, M. Nakano","doi":"10.2526/JSEME.34.76_18","DOIUrl":"https://doi.org/10.2526/JSEME.34.76_18","url":null,"abstract":"In order to further improve the machining accuracy and machining speed of electrical discharge machining (EDMing), it is necessary to understand the gap condition during the EDMing process. In this paper, a new method of using ultrasonic waves to measure the gap condition is proposed. First, the possibility that the change in the quantity of bubbles existing in the gap between the electrode and the workpiece could be detected as a change in the attenuation factor of ultrasonic waves is confirmed through a fundamental experiment of the proposed detection method. Second, the method is applied to an actual EDMing process with several machining settings. From these experiments, the dissimilarity of the gap conditions under several EDMing processes is clarified and the fact that the gap is filled with bubbles for most of the machining period is confirmed. Third, a comparative experiment is conducted to investigate the influence of the amount of bubbles in the gap on machining efficiency. As a result of the experiment, it is ascertained that machining with a small amount of bubbles has higher efficiency than machining with a large amount of bubbles. These results provide useful information for constructing the most suitable EDMing control system for improving machining performance.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125967297","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, the development of a rapid surface finishing method using an ECM process for stainless steel plates of standard size is described. Basic experiments are carried out first with a bar electrode 10mm wide and 3mm thick under a working gap of 0.2mm in order to establish the principle of the finishing process in which a stock removal rate of about 10μm/s is obtained. On the basis of the exprimental results, a trial apparatus which is designed for finishing stainless steel plates of the standard size of up to 5 feet in width is fabricated. It is equipped with a cylindrical electrode of 300mm in diameter to give the maximum peripheral velocity of 10m/s when rotated. Electrolyte is supplied to the working area by not only pumps but also tool rotation. Two masking sheets are extended upstream and downstream, respectively, to restrict the working area to between 8 and 12mm in length. Test runs are carried out to improve the gloss of SUS304 plates 4 feet wide and 8 feet long from the 2B to the BA finish level. The target level of gloss is realized under an electrode gap of 0.6mm with a feed rate of 600mm/min, applied voltage of 35 V and working current of 4000A.
{"title":"Rapid Surface Finishing of Stainless Steel Plates by Electrochemical Machining Process","authors":"K. Seimiya, T. Fujiwara","doi":"10.2526/JSEME.34.76_26","DOIUrl":"https://doi.org/10.2526/JSEME.34.76_26","url":null,"abstract":"In this paper, the development of a rapid surface finishing method using an ECM process for stainless steel plates of standard size is described. Basic experiments are carried out first with a bar electrode 10mm wide and 3mm thick under a working gap of 0.2mm in order to establish the principle of the finishing process in which a stock removal rate of about 10μm/s is obtained. On the basis of the exprimental results, a trial apparatus which is designed for finishing stainless steel plates of the standard size of up to 5 feet in width is fabricated. It is equipped with a cylindrical electrode of 300mm in diameter to give the maximum peripheral velocity of 10m/s when rotated. Electrolyte is supplied to the working area by not only pumps but also tool rotation. Two masking sheets are extended upstream and downstream, respectively, to restrict the working area to between 8 and 12mm in length. Test runs are carried out to improve the gloss of SUS304 plates 4 feet wide and 8 feet long from the 2B to the BA finish level. The target level of gloss is realized under an electrode gap of 0.6mm with a feed rate of 600mm/min, applied voltage of 35 V and working current of 4000A.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123332341","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}
Accretion machining by electrical discharge machining (EDM) with a high wear rate of green compact or semisintered electrodes has recently been carried out. Also, it has been observed that the wear rate of thin electrodes for various materials is very high with a high discharge current. In this study, a thin tungsten electrode is used for material accretion or surface modification of a small area. For this purpose, continuous discharge and single discharge machining experiments were performed by EDM with a thin electrode. Then the voltage and current waveforms and the cross section of the accreted surface were observed. In accretion machining, these waveforms revealed a continuous short-circuit phenomenon and a wire explosion phenomenon subsequent to the continuous short-circuited state. These observations indicated that the accreted layer was very hard (1000HV) and that the accretion area was very small (150μm in diameter). This clearly indicates that microaccretion machining can be performed using this technique.
{"title":"Accretion Machining by EDM with Thin Electrode (1st Report)","authors":"H. Takezawa, N. Mohri, K. Furutani","doi":"10.2526/JSEME.34.76_34","DOIUrl":"https://doi.org/10.2526/JSEME.34.76_34","url":null,"abstract":"Accretion machining by electrical discharge machining (EDM) with a high wear rate of green compact or semisintered electrodes has recently been carried out. Also, it has been observed that the wear rate of thin electrodes for various materials is very high with a high discharge current. In this study, a thin tungsten electrode is used for material accretion or surface modification of a small area. For this purpose, continuous discharge and single discharge machining experiments were performed by EDM with a thin electrode. Then the voltage and current waveforms and the cross section of the accreted surface were observed. In accretion machining, these waveforms revealed a continuous short-circuit phenomenon and a wire explosion phenomenon subsequent to the continuous short-circuited state. These observations indicated that the accreted layer was very hard (1000HV) and that the accretion area was very small (150μm in diameter). This clearly indicates that microaccretion machining can be performed using this technique.","PeriodicalId":269071,"journal":{"name":"Journal of the Japan Society of Electrical-machining Engineers","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115704783","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 study, EDM with a powder suspended dielectric has been applied in order to improve the surface quality of workpieces. WC(tungsten carbide) as a suspended powder and DC53(die steel for cold working) as workpieces were both adopted. Just after the WC powder was suspended into the dielectric, the surface of the workpiece was not modified but machined. As the discharge time for modification was accumulated, the surface became modified. After confirming that the surface was modified with the WC powder suspended dielectric, the effects of the discharge time per treatment on the characteristics of the modified layers were investigated. The longer the discharge time per treatment was, the harder the surface of the improved layer became. This is due to the increase of the produced amount of WCi-X. Ohgoshi wearing-out test was performed to evaluate the wear resistance of the improved layers. It revealed that the worn volume of the improved layer was decreased maximally by about 10% as compared to that of the base steel. key words: EDM, surface modification, powder, dielectric 1. 緒 言 放電加 工法 とは, 主 として油や水な どの液 中で発 生 させたパルス放電 を利用 し, 材料を 除去する加 工法である. 近年, この液 中での パルス放 電を表面改質 に適用 しよ うとす る試 み がな され ている1)2). その主な 手法 として は, 放電 の衝撃力を利用 して電極材 を工作物 へ移行 し改質層を形成す る方法(以 降, 電極 材移行方式 と記す), お よび放 電加 工油 中に 導電性粉末 を混入 し粉末成分に より改質層を 形成す る方法(以 降, 粉末混入方式 と記す) の二つが挙げ られ る. 電極材移行方式 は, 電極材 と同一も しくは その炭化物か らなる硬質膜を比 較的厚 く形成 できる とい った理 由か ら, 精力的に研 究が行 われ ている3)4). 一方, 粉末混 入 方式 は, 放 電加工におけ る仕上 げ面粗 さの改善5)と いっ た観点か ら研 究が開始 されているための, 当 初 は表面改質に関す る研究は少 なく6), 近年 にな り研 究例7)8)が増えてきた. 粉末混入方式 では, 粉末を放電加 工油中に 混入するこ とで, 工作物表面上に粉末成分 を 添加できる. このためその用途に応 じて必要 とされ る, 母材 とは異なる表面特性 を簡便な 手法で付与 できる. また, 多成分 か らなる粉 末を用いれ ば, 一度に多成分を工作物表面に 移行できる. このよ うに, 粉末混入方式では, 幅広い組成 の改質層 を簡便な方法で形成す る ことが可能 と思われ る. そこで本研究では, 粉末混入方式 を取 り上 げ, この方法 により放電加工 と関連 の深い金 型材へ硬質膜 を形成す るこ とを試みた. 冷問 * 電気加工学会全国大会(1998)に て発表 **神 奈川県産業技術総合研究所(海 老名市下
{"title":"Surface Modification Using EDM with Powder Suspended Dielectric","authors":"Toshitaka Satsuta, K. Hirai, M. Yoshizawa","doi":"10.2526/JSEME.34.22","DOIUrl":"https://doi.org/10.2526/JSEME.34.22","url":null,"abstract":"In this study, EDM with a powder suspended dielectric has been applied in order to improve the surface quality of workpieces. WC(tungsten carbide) as a suspended powder and DC53(die steel for cold working) as workpieces were both adopted. Just after the WC powder was suspended into the dielectric, the surface of the workpiece was not modified but machined. As the discharge time for modification was accumulated, the surface became modified. After confirming that the surface was modified with the WC powder suspended dielectric, the effects of the discharge time per treatment on the characteristics of the modified layers were investigated. The longer the discharge time per treatment was, the harder the surface of the improved layer became. This is due to the increase of the produced amount of WCi-X. Ohgoshi wearing-out test was performed to evaluate the wear resistance of the improved layers. It revealed that the worn volume of the improved layer was decreased maximally by about 10% as compared to that of the base steel. key words: EDM, surface modification, powder, dielectric 1. 緒 言 放電加 工法 とは, 主 として油や水な どの液 中で発 生 させたパルス放電 を利用 し, 材料を 除去する加 工法である. 近年, この液 中での パルス放 電を表面改質 に適用 しよ うとす る試 み がな され ている1)2). その主な 手法 として は, 放電 の衝撃力を利用 して電極材 を工作物 へ移行 し改質層を形成す る方法(以 降, 電極 材移行方式 と記す), お よび放 電加 工油 中に 導電性粉末 を混入 し粉末成分に より改質層を 形成す る方法(以 降, 粉末混入方式 と記す) の二つが挙げ られ る. 電極材移行方式 は, 電極材 と同一も しくは その炭化物か らなる硬質膜を比 較的厚 く形成 できる とい った理 由か ら, 精力的に研 究が行 われ ている3)4). 一方, 粉末混 入 方式 は, 放 電加工におけ る仕上 げ面粗 さの改善5)と いっ た観点か ら研 究が開始 されているための, 当 初 は表面改質に関す る研究は少 なく6), 近年 にな り研 究例7)8)が増えてきた. 粉末混入方式 では, 粉末を放電加 工油中に 混入するこ とで, 工作物表面上に粉末成分 を 添加できる. このためその用途に応 じて必要 とされ る, 母材 とは異なる表面特性 を簡便な 手法で付与 できる. また, 多成分 か らなる粉 末を用いれ ば, 一度に多成分を工作物表面に 移行できる. このよ うに, 粉末混入方式では, 幅広い組成 の改質層 を簡便な方法で形成す る ことが可能 と思われ る. そこで本研究では, 粉末混入方式 を取 り上 げ, この方法 により放電加工 と関連 の深い金 型材へ硬質膜 を形成す るこ とを試みた. 冷問 * 電気加工学会全国大会(1998)に て発表 **神 奈川県産業技術総合研究所(海 老名市下","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":"122970332","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}
{"title":"Development of Electrical Discharge Coating Machine (EDCOAT)","authors":"A. Goto, T. Moro, K. Matsukawa","doi":"10.2526/JSEME.34.38","DOIUrl":"https://doi.org/10.2526/JSEME.34.38","url":null,"abstract":"","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":"114934156","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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