| 摘要 |
PROBLEM TO BE SOLVED: To provide a suitable process for producing a novel magnetic disk when this process is applied to the case where plural final products are cut off from a large-sized substrate previously subjected to a surface treatment and an apparatus for production for this purpose. SOLUTION: A base material 100 is irradiated with a laser beam of the locus determined by the contour of the inside diameter of the final product prior to cutting of the magnetic disk base material formed by previously subjecting the large-sized substrate to the surface treatment, by which plural central holes 901 are formed. Next, the base material region having the central hauls 901 as a concentric circle is irradiated with the laser beam of the locus determined by the contour of the outside diameter of the final product 100 in the state of holding the base material 100 by the central holes 901, by which the base material 100 is cut and the final product 100 is obtd. The base material 100 may also be precut to the plural base material pieces of a desired external shape size (for example, the square shape slightly larger than the external shape size of the final product) before or after the formation of the central holes 901. |
