| 摘要 |
PURPOSE:To keep molten resin temperature and plasticizing capacity at constant by a method wherein the changes of the molten resin temperature and of plasticizing capacity can be controlled by automatically regulating the rotational frequency and back pressure of a screw in the plasticizing process of an injection molder. CONSTITUTION:With the increase in the rotational frequency of a screw, the plasticized resin temperature at the tip of the screw also increases, because the increase in the rotational frequency of the screw brings the increase of the released value of internal frictional heat generation simultaneously with the increase of plasticizing capacity. Respective set values of resin temperatures at positions corresponding to those of the screw, at which respective thermocouples 21 are imbedded, are outputted from a resin temperature setter 26 to first subtracters 27 so as to calculate the differences between the actual values and the set values of the resin temperatures in order to output the calculated differences to a plasticizing controller 29. A screw position setter 25 outputs the set values of the screw position in relation to the elapse of time since the start of plasticizing. A second subtracter 28 calculates the difference between the output from the screw position setter 25 and the output from a screw position detector 11 so as to output the calculated difference to the plasticizing controller 29, which calculates the request signals in relation to the rotational frequency and to the back pressure of the screw. Because manipulated variables are two, i.e. the rotational frequency and back pressure of the screw, the number of controlled variables, which can coincide with set value, becomes also two.
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