Patent Number: 8,869,559

Title: Method of manufacturing a glass substrate for magnetic disk

Abstract: A manufacturing method of a glass substrate for magnetic disk including a pair of principal surfaces is disclosed The method includes the steps of: dropping process for dropping a lump in vertically downward direction, the lump made by cutting molten glass; pressing process for forming a sheet glass material by sandwiching substantially simultaneously the lump from both sides of the dropping path of the lump with surfaces of the pair of dies at the timing when at least a cut mark of the lump protrudes from a pair of dies facing together, and performing press forming to the lump; and removing process for removing the glass material protruding from the pair of dies.

Inventors: Isono; Hideki (Kofu, JP), Eda; Shinji (Nirasaki, JP)

Assignee: Hoya Corporation

International Classification: C03B 11/08 (20060101)

Expiration Date: 2018-10-28 0:00:00