| 摘要 |
PROBLEM TO BE SOLVED: To surely fix the abrasive grain to a core material, and to compara tively easily obtain a specific diameter, by impregnating a core material obtained by binding ceramic long fibers, with a thermosetting resin, and thermal ly hardening the same, so that the abrasive grain is held by the thermosetting resin. SOLUTION: A core material 1 is prepared by binding several pieces of alumina ceramic long fibers 1a of severalμm of thickness. The core material 1 cut by about 300-400 mm, is inserted into a metal mold, and a matter thermosetting resin is injected and packed in a cavity of the metal mold warmed at more than a hardening temperature of the resin, by a specific injection pressure, so that a drill material obtained by putting the thermosetting resin 2 around the core material 1, is molded. On this occasion, the resin is penetrated through several pieces of ceramic fibers 1a forming the core material 1, so that core material 1 and the thermosetting resin 2 are strongly integrated. The abrasive grain 3 is attached to the surface of the drill material taken out of the metal mold, by the pressure, so that the abrasive grain is held by the drill material so that it is embedded in the thermosetting resin 2.
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