| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2006: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
Nozzles for fuel injection as well as spinning-spinneret and wire-drawing dies are produced using stainless steel, high-speed steel, cemented carbide, and other heavy-duty materials. Cemented carbide which is about 2 times harder than high-speed steel, exhibits superior wear and heat resistance properties. As a method for processing cemented carbide with a fine hole, wire electrical discharge machining (WEDM) is generally used. However, surface defects such as cracks and microcraters are generated on the inner wall of the hole by WEDM. It is desirable to remove as many of these surface defects as possible.
Lapping of the inner wall of the hole has usually been performed by finishing by hand using a bar daubed with diamond paste. However, it is difficult to completely remove the surface defects using this method.
For the purpose of completely removing the surface defects generated in cemented carbide with a fine hole by WEDM, a new polishing method which combines the surface modification using an oxidizing treatment with flow polishing using abrasives was developed, and the following results are obtained.
(1)A new polishing method which combines surface modification using an oxidizing treatment with flow polishing using abrasives was developed for the purpose of completely removing the surface defects.
(2)By applying the combined polishing method to the cemented carbide with a fine hole subjected to WEDM, a superior surface in terms of surface integrity was obtained in a short period of 10 minutes.
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