| 摘要 |
Extruding plastic material utilizing an extruder comprising a cylindrical bore having an inlet at one end and an outlet at the other end in which a single shaft screw is rotatably mounted. The periphery of the screw is formed with a first land that defines a main helical channel that extends throughout the length of the screw. At a point downstream from the inlet, the lead of the first land is increased and a second land begins defining with the first land an auxiliary helical channel. The periphery of the second land is spaced from the surface of the bore a greater distance than the periphery of the first land and the second land terminates at a point spaced rearwardly from the end of the first land and in spaced relation thereto. |
