巻号一覧
30 巻 (1996)
- 65 号 p. 1-
- 64 号 p. 2-
- 63 号 p. 1-
30 巻, 64 号
選択された号の論文の4件中1～4を表示しています
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第2報 直線荒加工の加工精度について岩田 康, 小原 治樹, 大住 剛, 松田 裕二, 石津 稔之1996 年 30 巻 64 号 p. 2-10
発行日: 1996/07/31
公開日: 2010/03/12
ジャーナル フリーPrecisions of Wire-EDM are spoiled by a wire deflection and a wire vibration during the machining.
In the previous report, we described about the simulating procedure of Wire-EDM, treating from voltage supply to discharge, explosion, machining, wire movement and their repetition. Also we showed experimentally obtained characteristics of ignition delay times and gap lengths, which is necessary for the simulation. Next we showed few analyzed results and described that the viscosity in cut groove should be greater than that in open space.
In this report we investigate the propriety of the simulation model analyzing straight rough cuttings, and describe the influence of electrostatic force and EDM conditions on cutting accuracies.抄録全体を表示PDF形式でダウンロード (5379K) -
橋口 清人, 猪飼 健夫, 上出 諭吉1996 年 30 巻 64 号 p. 11-17
発行日: 1996/07/31
公開日: 2010/03/12
ジャーナル フリーIn EDM, the pulse duration τ which minimize the electrode wear ratio γ (=tool electrode erosion/workpiece erosion) are above 100μs. In that case, the workpiece is negative electrode.
The present investigation is an exploration of the cathode heat input on the surface of the workpiece given by a single pulse discharge under these conditions of pulse duration τ. The use of the equivalent heat input radius [a] to calculate the local molten zone on the surface of work metal (cathode) makes a special feature of the present investigation. The equivalent heat input radius [a] instead of the cathode spot radius which changes every moment was determined as a semi-experimental equation by using the theoretical equation of thermal conduction. The radius [a] with a general idea such as the effective value in the alternative current of electrical engineering is nonexistant.
As the result, It became evident that the heat input to the cathode (work piece) spot can be treated for the constant value in a single pulse discharge which is provided by both the current I and the pulse duration τ. These results agree well with other reports, in which the cause have not been explained. In other words, it was explained by using the equivalent heat input radius [a] that the heat input to the cathode spot on the workpiece can be treated by a constant during a single pulse discharge.
And also, it is conclude that Joule heating can by almost ignored on experimental conditions in the present paper.抄録全体を表示PDF形式でダウンロード (882K) -
田村 武夫, 桜井 純也1996 年 30 巻 64 号 p. 18-26
発行日: 1996/07/31
公開日: 2010/03/12
ジャーナル フリーIn EDM processing of steel, a hard white layer, different from the parent metal, forms on the surfaces because of rapid heating and cooling. Cracks and micro-craters appear on the surface of the white layer depending on machining conditions used. Such heat-affected zones (HAZ) can greatly shorten the life of metal molds.
In this study, it is considered that the generation of cracks is caused by tensile stress based on the phase change of the material. Thus, an analysis of thermal stress including the phasechanged process is suggested. Thermal stress distribution is calculated using FEM with consideration of complicated boundary conditions due to phase change. And, cracks generated by EDM of die steel for cold working SKD11 were studied experimentally under various machining conditions. The form of generated cracks were examined, and the following results were obtained. Tensile stresss above 850MPa arises in the solidified region (white layer) of the material, which exceeds the value of tensile strength of the parent material used. The behavior of generated cracks could be readily explained with consideration of both the change in time and spatial distribution of the thermal stress.抄録全体を表示PDF形式でダウンロード (7141K) -
吉田 政弘, 国枝 正典1996 年 30 巻 64 号 p. 27-36
発行日: 1996/07/31
公開日: 2010/03/12
ジャーナル フリーDielectric liquids such as kerosene based oils are generally preferred in the EDM process because such liquids are regarded as indispensable for material removal. As environmemtal hazards, cost, etc., are demerits with those liquids, the EDM without any such medium was thought to be important to explore. With this intention, the present study was formulated in which debris formation and their distribution on the working surface due to single pulse discharge in the EDM process under air and liquid (gelatin) were examined. Specifically, the EDM gap after single pulse discharge was monitored and during the process, total debris volume removed was measured. The position of scattered debris and their size distribution were also obtained.
In air, almost all the debris removed were scattered on the electrode surface, got attached there and solidified. In liquid, the scattered debris were, however, mainly distributed at the bound ary of bubble formed due to evaporation and disassociation of gelatin. The bubble formation in the liquid and their explosive expansion contributed to the material removal. Such contribution was found effective only when the pulse duration was less than 90μsec, whereas the material removal in liquid was almost the same as that of in air for a pulse duration longer than 90μsec. As far as the material removal is concerned, therefore, EDM may be performed in air provided the debris generated in the process be flushed out of the EDM gap before they get solidified on the electrode surface.抄録全体を表示PDF形式でダウンロード (6334K)
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