| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for drawing a glass preform capable of obtaining a glass rod having a stable outer diameter, for which a plurality times of fine drawing adjustment by a glass lathe are not required even after drawing a glass preform with a large diameter having a steeply tapered part shorter than the length of a heater. SOLUTION: In heating and softening a glass preform and drawing it for thinning to a required diameter, a preliminary drawing is applied where the tapered part of the glass preform is heated, softened and drawn to elongate the tapered part, a transfer mechanism for sending the glass preform into a heating furnace is elevated to a specified level, and then starting drawing again and a main drawing is applied where the whole of the glass preform is drawn successively. COPYRIGHT: (C)2006,JPO&NCIPI
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