| 摘要 |
PROBLEM TO BE SOLVED: To obtain the surface, which is smooth and the hardness of which is made higher and which wears little, of a mold by a method wherein the surface of the mold is mirror-polished and, at the same time, jetted with minute particle materials having the hardness more than or equal to the hardness of the finished mold so as to apply a lapping treatment to the surface part of the hardened mold. SOLUTION: In a surface heat working treatment 52, two processes such as a surface hardening treatment and a shot-peening treatment in an ordinary heat treatment are simultaneously carried out in one process. When shot-peening materials or minute particle materials becomes smaller, their jetting speeds increase and, at the same time, heat is generated on an optical disc mold as a matter to be worked, the jetted surface temperature rises in proportion to the increase of the jetting speeds, the surface temperature reaches higher than the metal transformation point of the mold, resulting in producing a quench hardening and tempering state in the mold. Accordingly, a heat treatment and a shot-peening are carried out in one process. In the lapping treatment 53 of the mold, the lapping material, the particle side of which is smaller than that of the shot-peening material, is used. |
