| 摘要 |
<p>There is disclosed a method for controlling an extrusion line for foamed insulation cables. In this method, a foaming insulation compound composed of a polyolefin resin and a foaming agent is supplied to an extruder, and extruded and coated as a foamed insulation onto a continuously fed cable conductor at a temperature higher than a decomposition temperature of the foaming agent to produce a cable that is subsequently passed through a cooler unit for controlling the outside diameter and electrostatic capacity of the foamed insulation. The system is controlled so that a plurality of measured variables including a plurality of controlled variables such as the outside diameter and the electrostatic capacity and condition variables affecting the controlled variables, such as a cylinder temperature of the extruder, a crosshead temperature of the extruder, a resin temperature and a resin pressure in the crosshead, are variable in predetermined correlation with a plurality of manipulated variables as input parameters which vary the controlled variables, such as a line speed of the extrusion line, a voltage applied to a preheater disposed in front of the extruder, an RPM of a screw in the extruder, a voltage applied to a cylinder heater in the extruder, a voltage applied to a crosshead heater, and a distance which the cooler unit is movable. The controlled variables are controlled so as to be adjusted into target values therefor by manipulation variables which are produced by effecting an integrating action on variable factors which are derived from the differences between the target values and the controlled variables.</p> |
