| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method which restricts occurrence of grooves which are discriminable from shear marks of molten glass and extend from the principal surface in the depth direction, in producing a glass blank for magnetic discs having a pair of principal surfaces by press molding.SOLUTION: A method of producing a glass blank for magnetic discs includes a treatment of cutting flowing molten glass 20 to form lumps 24 of the molten glass, a treatment of causing the lumps 24 to fall, a treatment of pressing from both sides of the falling path for the lumps 24 with a pair of dies 50 and 60, and a treatment of increasing the viscosity of the surface of the lumps 24 relative to the viscosity of the molten glass 20 on cutting so as to restrict occurrence of streak-like grooves due to bending deformation in which the falling lumps 24 come in contact with one of the molds and folded.</p> |
