| 摘要 |
PURPOSE:To regulate the diameter of a tube effectively and precisely by altering the discharge amount of an extruder and the drawing rate of a tube correlatively according to a preset program at a desired latering ratio within a limited range. CONSTITUTION:Using an extruder whose discharge amount can be abruptly increased or reduced, a thermoplastic synthetic resin is extruded into a tube through an annular die, drawn at an alterable drawing rate, and solidified by cooling, where the turning rate (discharge amount) and the drawing rate of the extruder are altered correlatively according to a preset program at a desired altering ratio within a limited range. By regulating the amount of a fluid, e.g., air, blown into through the hole provided to the annular die from a fluid-blowing means provided, the thickness of the tube can also be altered. |
