| 摘要 |
PURPOSE:To prevent the injuries of a disk due to the exfoliation of a burr and to avoid the moisture absorption at each cut end of an index hole part and a center hole part, by coating a protecting film to the outer circumferential part of a blanked disk as well as to said cut ends. CONSTITUTION:A sag part is produced at a cut end formed when a medium is blanked into a disk form, and many cracks and burrs are burmed near the sag part. This sag part is coated with resin 4. As a result, no crack is produced even with million calipers or more with no exfoliation caused by burr. Furthermore the moisture absorption is avoided at the cut end since it is covered with resion. This prevents the exfoliation of a magnetic layer due to the misture absorption. |
