| 摘要 |
PURPOSE:To prevent the galling and biting of a cut member and to obtain an optical element with precision in dimensions and weight by cutting off the surplus part of a molten glass material with a forming device of specified structure. CONSTITUTION:A cutting member 7 movable along the periphery of a forming die member 6 and used for cutting off the surplus part of a molten glass material is provided on the periphery of the member 6 for press-forming the material, a minute gap of 20-50mu is held between the inner periphery of the blade head of the cutting member 7 and the periphery of the member 6, and a temp. control means for holding the gap at a specified value is provided in the cutting member 7. In such a forming device, molten glass 2 is discharged from a nozzle 1, the opposed die member 5 and 6 held at a specified temp. are driven to press the part of the molten glass 2 except the tip with forming faces 5a and 6b to a specified thickness, the cutting member 7 is slid back and forth along the periphery of the die member 6 in the direction of the die member 5 to cut off the surplus glass material 22, and the formed part 21 is cooled from the periphery and taken out. |
