| 摘要 |
PURPOSE:To enhance display the inner face smoothness of a synthetic resin pipe and enable a liquid transportation pipe to be extrusion-molded by placing the tip end of a mandrel part somewhat inside of the tip end of an outer mold. CONSTITUTION:A resin flow path 3 is made up of a tapered enlargement 31, a spider passage 32, a tapered contraction part 33 and a round parallel part 34, and an outer mold tip end 20 and a mandrel tip end 10 are placed inside of an outer tip end 20. Meanwhile annular resin being spaced apart from the mandrel tip end 10 in its inner surface reaches the position of the outer mold tip end 20, it keeps contact with the outer mold inner surface and receives heats from a temperature control heater of the outer mold 2 to maintain a sufficient heat-melted state. It is preferable that a distance DELTAL is made 2-30mm between the mandrel tip end 10 and the outer mold tip end 20. |
