Manufacturing method of a sheet glass material for magnetic disk, manufacturing method of a glass substrate for magnetic disk
AssigneeHoya Corporation
InventorHideki Isono
Life of this patent
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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 of molten glass; pressing process for forming a sheet glass material by sandwiching simultaneously the lump from both sides of the dropping path of the lump with surfaces of the pair of dies facing together, and performing press forming to the lump; and machining process for machining the sheet glass material, wherein the press forming sandwiches the lump while moving the pair of dies in the direction of drop of the lump so that relative speed of the lump to that of the pair of dies approaches zero.
Claims6
A manufacturing method of a sheet glass material for a magnetic disk including a pair of principal surfaces, the method comprising:
- performing a cutting process for cutting molten glass to cause a lump of molten glass to drop;
- and
- performing a pressing process for obtaining a sheet glass material by sandwiching simultaneously the dropping lump from both sides of the dropping path of the lump with surfaces of a pair of dies facing together, and performing press forming on the lump;
- such that the press forming sandwiches the lump while moving the pair of dies in a vertical direction so that a relative velocity of the lump to that of the pair of dies decreases.
A manufacturing method of a glass substrate for a magnetic disk, the method comprising
- performing a cutting process for cutting molten glass to cause a lump of molten glass to drop;
- performing a pressing process for obtaining a sheet glass material by sandwiching simultaneously the dropping lump from both sides of the dropping path of the lump with surfaces of a pair of dies facing together, and performing press forming on the lump such that the press forming sandwiches the lump while moving the pair of dies in a vertical direction so that a relative velocity of the lump to that of the pair of dies decreases;
- performing a grinding process for grinding principal surfaces of the sheet glass material obtained with the pressing process using fixed abrasive grains;
- and
- performing a polishing process for polishing the principal surfaces using loose abrasive grains after the grinding process.
Dependencies are inferred from the claim text.