METHOD FOR MANUFACTURING GLASS MATERIAL FOR MAGNETIC DISK AND METHOD FOR MANUFACTURING GLASS SUBSTRATE FOR MAGNETIC DISK

摘要

PROBLEM TO BE SOLVED: To efficiently manufacture a glass material for a magnetic disk and a glass substrate for a magnetic disk suppressing surface ruggedness (surface roughness, waviness or flatness) of a principal surface and sag of an end part.

SOLUTION: There is provided a method for manufacturing a glass material for a magnetic disk, the method comprising: a dropping step for dropping lumps of molten glass; and a press step for forming a plate-like glass material by press molding by sandwiching the lumps on the surface of a pair of molds facing each other from both sides of a dropping path of the lumps. At least one of the pair of molds has a protruding shape toward the dropping path of the lumps.

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