摘要 |
A capillary has a face surface 13 formed at the tip end thereof so that the face surface 13 inclines toward the center thereof so as to have a tapered shape, and has a through hole 11 formed therethrough so as to permit wire to be placed therethrough so that the through hole 11 has an opening 12 at the center of the face surface 13. The inclination angle theta of the face surface 13 relative to the plane perpendicular to the axis of the capillary and including the opening 12 of the through hole 11 is in the range from 4° to 15°, and the height h of the face surface 13 along the axis of the capillary is equal to or greater than the thickness of the wire 2.
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