| 摘要 |
PROBLEM TO BE SOLVED: To provide a flame polishing method for a glass preform in which the occurrence of cracks can be suppressed. SOLUTION: In the flame polishing method of the glass preform to perform the flame polishing of the glass preform 10 where a glass rod 11 and dummy rods 12, 13 are connected via connection parts 14, 15, a flame polishing step of the glass rod 11 is performed after a strain-removing step to remove strain at the connection parts 14, 15 by heating the connection parts 14, 15 and the neighborhood of the connection parts 14, 15. In the strain-removing step, flame polishing is simultaneously performed from the connection part 14 toward the end part of the glass preform 10 and the flame polishing step starts from the connection part 15. COPYRIGHT: (C)2009,JPO&INPIT
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