| 摘要 |
PROBLEM TO BE SOLVED: To effectively perform the cooling of an annular die and to improve productivity of artificial diamond or the like in a mold device of a punch and a die by forming, on the annular die for high temperature and high pressure, cooling flow passages or cooling grooves extending from the top surface to the bottom surface thereof. SOLUTION: When manufacturing artificial diamond or cubic boron nitride (CBN) by a high temperature and high pressure method using a mold device consisting of a punch A and an annular die B, on the annular die B of cemented carbide, cooling flow passages extending in the axial direction of the die from top surface to the bottom surface thereof are formed. These flow passages are formed in straight lines, or in spirals, or in twists. By causing a coolant of temperature of <10 deg.C to flow in the cooling flow passages, the cooling of the annular die B is performed. By this cooling, the temperature of the die is preferably lowered to a prescribed critical point or less to attain the die performance about 10 times extra as compared with the conventional die.
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