摘要:
A method for manufacturing a glass blank for magnetic disk and a method for manufacturing a glass substrate for magnetic disk are provided which are capable of producing a glass blank for magnetic disk having a good surface waviness by press forming. The method includes a forming process of press-forming a lump of molten glass using a pair of dies, wherein in the forming process, press forming is performed using thermally equalizing means for reducing a difference in temperature in the press forming surface of the die during pressing of the molten glass.
摘要:
A method for manufacturing a glass substrate for magnetic disk, the internal strain of which is reduced without performing annealing treatment, is provided. The method includes a forming process of forming a plate-shaped glass blank by pressing a lump of molten glass using a pair of dies, wherein the method includes: a removing process of removing at least a part of a residual stress layer formed on the principal face of the glass blank press-formed in the forming process; and a process of forming a donut-shaped glass substrate by subjecting the glass blank after the removing process to machining.
摘要:
A manufacturing method of a sheet glass material for magnetic disk, the method includes, dropping process for dropping a lump of molten glass; pressing process for sandwiching simultaneously the lump from both sides of the dropping path of the lump with surfaces of a pair of dies facing together, and performing press forming to the lump to obtain a sheet glass material, wherein at least one of the pair of dies has a concave shape with respect to the dropping path of the lump.
摘要:
A method for manufacturing a glass substrate for magnetic disk, the internal strain of which is reduced without performing annealing treatment, is provided. The method includes a forming process of forming a plate-shaped glass blank by pressing a lump of molten glass using a pair of dies, wherein the method includes: a removing process of removing at least a part of a residual stress layer formed on the principal face of the glass blank press-formed in the forming process; and a process of forming a donut-shaped glass substrate by subjecting the glass blank after the removing process to machining.
摘要:
A method for manufacturing a glass substrate for magnetic disk is provided. The method includes a forming process of press-forming a lump of molten glass using a pair of dies, wherein in the forming process, the cooling rate of the molten glass during pressing is controlled so that a first compressive stress layer is formed on a pair of principal faces of a glass blank that is press formed, and the method includes a chemically strengthening process for forming a second compressive stress layer on a pair of principal faces of a glass substrate formed using the glass blank after the forming process.
摘要:
To provide a method for manufacturing a glass blank for magnetic disk and a method for manufacturing a glass substrate for magnetic disk, which are capable of producing a glass blank for magnetic disk having a good surface waviness by press forming, and a method for manufacturing a glass substrate for magnetic disk. A method for manufacturing a glass blank for magnetic disk, which includes a forming process of press-forming a lump of molten glass using a pair of dies, wherein in the forming process, press forming is performed using thermally equalizing means for reducing a difference in temperature in the press forming surface of the die during pressing of the molten glass.
摘要:
A manufacturing method of a sheet glass material for magnetic disk, the method includes, dropping process for dropping a lump of molten glass; pressing process for sandwiching simultaneously the lump from both sides of the dropping path of the lump with surfaces of a pair of dies facing together, and performing press forming to the lump to obtain a sheet glass material, wherein at least one of the pair of dies has a convex shape with respect to the dropping path of the lump.
摘要:
Provided is a method of manufacturing a glass blank for a magnetic recording medium glass substrate, including: manufacturing a glass blank by at least press molding a falling molten glass gob with a pair of press molds both so as to face each other in a direction perpendicular to a direction in which the molten glass gob falls, in which: the molten glass gob is formed of a glass material having a glass transition temperature of 600° C. or more; and when the press molding is carried out so that the molten glass gob is completely extended by pressure and molded into a flat glass between press-molding surfaces of the pair of press molds, at least a region in contact with the flat glass in each of the press-molding surfaces of the pair of press molds forms a substantially flat surface. Also provided are a method of manufacturing a magnetic recording medium glass substrate and a method of manufacturing a magnetic recording medium each using the method of manufacturing a glass blank for a magnetic recording medium glass substrate.
摘要:
A method for manufacturing a glass blank for magnetic disk and a method for manufacturing a glass substrate for magnetic disk are provided which are capable of producing a glass blank for magnetic disk having a good surface waviness by press forming. The method includes a forming process of press-forming a lump of molten glass using a pair of dies, wherein in the forming process, press forming is performed using thermally equalizing means for reducing a difference in temperature in the press forming surface of the die during pressing of the molten glass.
摘要:
A manufacturing method of a sheet glass material for magnetic disk, the method includes, dropping process for dropping a lump of molten glass; pressing process for sandwiching simultaneously the lump from both sides of the dropping path of the lump with surfaces of a pair of dies facing together, and performing press forming to the lump to obtain a sheet glass material, wherein at least one of the pair of dies has a convex shape with respect to the dropping path of the lump.