| 摘要 |
PURPOSE:To form efficiently and with high dimension accuracy a spinneret to which many fine spinning holes are adjacent, by piercing successively a stepwise pierced raw solution leading-in hole and a pierced raw solution discharging hole at a position where they are not adjacent to each other. CONSTITUTION:When piercing a spinning hole 6' on a spinneret plate 1, first of all, the first leading-in hole 3a is pierced successively in numerical order by a punch tool at a position where respective holes are not adjacent in one direction through four directions in the circumference, and the first leading-in hole 3a is formed like a multi-ring. Subsequently, the second leading-in hole 3b is pierced in numerical order on the bottom of said each first leading-in hole 3a by a punch tool whose tip conical angle is small. Also, a raw solution leading-in hole 3' is formed by piercing successively the third leading-in hole 3c in numerical order on the bottom of the second leading-in hole 3b by a punch tool 2c whose tip conical angle is small. Thereafter, the spinning hole 6' is formed by piercing successively an undiluted solution discharging hole 5' in order of a number on the bottom of each leading-in hole 3' by a punch tool 4', by which a spinneret 7' is obtained. |
