| 摘要 |
PURPOSE: To reduce a die swell problem which expands when a compressed extrusion material is discharged by placing a flow rate throttling unit which is so operated as to reduce a pressure difference between forming members of an extrusion die in a channel between an extruder and the die. CONSTITUTION: An extruder 8 comprises an extrusion head 10 which has a fixed or stationary central part 12, a rotatable upper part 14 and a lower part 16. Many extrusion passages 18 to 22 are formed in the head 10, and extended to an extrusion die 26 via a cassette 24. Further, extruding materials are supplied to the channels 18 to 22 by extruders 28 to 32 having drive motors 34 to 38, respectively. In this case, channel throttles 44 to 48 are so disposed in the channels 18 to 22 as to lower the pressure between the die 26 and the extruders 28 to 32. The pressures of the throttles 44 to 48 at the downstream side are detected by pressure sensors 54 to 58, and the speeds of the extruders 28 to 32 are controlled in response to the detected results by a controller 40. |
