| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass preform manufacturing method in which it is difficult to generate a loss of clarity during molding.SOLUTION: In a molding step, gas is supplied between a glass lump 20 made of molten glass liquid and a molding die 11, and the glass lump 20 is cooled while it is floated from the molding die 11 and held, so as to mold a glass preform 21. While a quantity of heat is being provided to the glass lump 20, the molding step is performed. |
