| 摘要 |
PURPOSE:To mold a hollow member without surface defect, inner defect, disconnection stably for a long period of time by specifying the pressure condition of pressurized fluid to be fed to the hollow part of resin. CONSTITUTION:Polyoxymethylene supplied from a hopper 1 is melted and plasticized by an extruder 2, then guided through a heated double die 3 to a sizing die 4 without exposing with the air to be specified in the outer diameter of a hollow part, and manufactured while cooling. The die 3 has an inner die 11 having a hole for feeding pressurized fluid such as air, nitrogen, and an outer die 12 provided at an annular gap outside the die 11, and the pressure of the fluid fed from the die 11 is maintained at a predetermined value of 0.5-5kg/cm<2>. Thus, surface, inner or shape defect is suppressed thereby to stably mold for a long period of time, thereby manufacturing a hollow member with high productivity and high efficiency. |
