| 摘要 |
PURPOSE:To decrease thermal influences and substrate distortions by subjecting a planar blank material having a prescribed thickness to laser cutting, thereby producing a base material for magnetic disks. CONSTITUTION:A CO2 laser, etc., are preferable as a laser for cutting and Ar, N2, etc., as an assist gas. The gaseous pressure is preferably in a range from 4 to 8kgf/cm<2>. A slab made of an aluminum alloy is first produced and is rolled to a rolled plate 2 of the thickness corresponding to the thickness t of the substrate 1 for the magnetic disks. The execution of washing of the rolled plate 2 between the rolling and the laser cutting is preferably avoided. After the inner peripheral 1a of the substrate 1 is cut, the outer peripheral part 1b is cut in the laser cutting. The substrate 1 is subjected to finishing, such as polishing, after the laser cutting. |
