| 摘要 |
PURPOSE:To reduce retention of resin, by a method wherein a resin inflow port from an extruding machine is opened in a die housing side in the middle of a rising limit and lowering limit of a ring plunger and a resin passage arriving at an outlet slit from the extruding machine is formed at the lowering limit position. CONSTITUTION:A ring plunger 28 which has sliding fitting dimensions dimensions and is capable of performing an up-and-down motion between the upper part of the inner circumferential surface of a die housing 20 communicated with an extruding machine with a resin passage 34 and the upper parts of outer circumferential surfaces of mandrels 23a, 23b. Then a resin inflow port from an extruding machine 31 side is opened in a die housing 20 side in the middle of a rising limit and lowering limit of the ring plunger 28. Then resin passages 25, 36 arriving at an outlet slit 29 of the die 20 from the extruding machine 31 are formed under a condition of a lowering limit position of the ring plunger 28. Hereby, a quality of a molded product is improved drastically. |
