| 摘要 |
PURPOSE:To make molding easy and contrive an improvement in strength, by a method wherein a molten state synthetic resin material extruded cylindrically is cooled and solidified by sucking to and abutting against the outer circumferential surface of the synthetic resin material by a rotary die having a spiral unevenness molding groove on an inner circumferential surface while turning the same. CONSTITUTION:A cylindrical die 12 is fitted over a cylindrical nipple 11 through an extrusion path 13, in an extrusion part 1. When a molten state synthetic resin material A is extruded cylindrically through the extruding path 13 of a molding device like this, the synthetic resin material A is sucked to and abutted against an unevenness molding groove 42 of a rotary die 4 and an uneven form A' in a wave form is formed by air pressure sent to an air chamber 6 through an air path 11e communicating with a recessed part 11a and air pressure (negative pressure) sucked through a vacuum path 43 communicating with the unevenness molding groove 42. The uneven form A' is formed into a spiral state with a rotation of the rotary die 4. Then the spiral uneven form A' is solidified by a cooling part 45 and formed unitarily with the synthetic resin material. |
