| 摘要 |
PURPOSE:To suppress the variation in size of gap to a minimum value by eliminating a part other than both ends in a slit prolonged direction from an opposite direction as a slit forming face or forming it to a recessed shape and penetrating the center part. CONSTITUTION:The slit 11 for head gap dividing respectively side cores 10a, 10b and a center core 10c from the lower part of a raw material 10 is formed and a cut recessed face 12 by cutting processing is formed. Since the recessed face 12 is formed at the center part other than both ends 10d, 10e in the slit prolonged direction of the raw material 10, parts becoming cores 10a, 10b and 10c form one body. A bonding molten glass 13 is filled in the gap in a furnace and a V-shaped slit 11a having an open angle by taking a vertical face of the center core 10c as a reference is added by ensuring a gap depth (d). The cores 10a, 10b and 10c are divided by a bonding member 13 by removing both end parts 10d, 10e and form one body also, then the face of both ends 10d, 10e is polished further so as to form a slid face for a tape or the like. |
