Journal of The Japan Society of Electrical Machining Engineers

[title in Japanese]

[in Japanese]

1999 Volume 33 Issue 73 Pages 10-17
Published: July 30, 1999
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.2526/jseme.33.73_10

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Fundamental Study of Accuracy of Wire EDM (3rd Report)

Improvement of Rough Cut Concave Large Corner R Accuracy by a Combined Power and Path Control

Haruki OBARA, Tamotsu KAWAI, Tsuyoshi OHSUMI

1999 Volume 33 Issue 73 Pages 18-22
Published: July 30, 1999
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.2526/jseme.33.73_18

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In this report, we propose a method to improve accuracy of concave large corner R by rough cut of a work piece where the corner R radius is greater than a half of cut groove width and the wire discharges symmetrically on whole front surface of the wire. In the control method, program path and discharge power are modified simultaneously at the corner R. The discharge power is adjusted so that difference between error of corner R on a middle surface and that on a top or a bottom surface of the work piece decreases within a allowable value. Program path is modified so that wire guides move along a path going a head of a desired corner R path, and the form of corner R on the top or the bottom surface of the work piece will be correct. The corner R radius is modified depending on the wire deflection.

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Surface Modification of Cold Working Die Steel, SKD11, using Laser Irradiation

Takeo TAMURA

1999 Volume 33 Issue 73 Pages 23-30
Published: July 30, 1999
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.2526/jseme.33.73_23

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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.

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Surface Modification by EDM with Carbon Powder Mixed Fluid using Titanium Electrode

Akira OKADA, Yoshiyuki UNO, Kazuhisa HIRAO, Takashi TAKAGI

1999 Volume 33 Issue 73 Pages 31-37
Published: July 30, 1999
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.2526/jseme.33.73_31

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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.

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[title in Japanese]

[in Japanese]

1999 Volume 33 Issue 73 Pages 38-42
Published: July 30, 1999
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.2526/jseme.33.73_38

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