| 摘要 |
PURPOSE:To permit to control easily the thickness distribution in the circumferential direction of molded product such as parison or the like by a method wherein a heating and cooling device is provided on the circumferential direction of the nozzle to control the temperature of circumference of the nozzle upon molding a material. CONSTITUTION:In case of controlling the thickness distribution in the circumferential direction of parison, the outer peripheral rim section of lower end of a mandrel 1 and the outer peripheral section of lower end of the main body 5 of nozzle are heated or cooled locally by the heating and cooling devices 6, 7. When the circumferential thickness of the parison is (t1) at right side and (t2) at left side, for example, and (t1)>(t2), only the right sides of the outer circumferential rim of lower end of the mandrel 1 and the outer circumferential section of lower end of the main body 5 of nozzle are cooled locally by the heating and cooling device 6, 7. When one part of the nozzle is cooled in such manner, the swell of the cooled section is enlarged while nozzle gap G is kept in constant in the circumferential direction, therefore, the thickness of the parison 8 becomes thick in this part locally. Accordingly, the thickness distribution in the circumferential direction of the parison 8 may be controlled properly by heating or cooling a necessary position in the circumferential direction of the nozzle properly. |
