摘要 |
The object of this invention is to suppress the generation of surge pressure at the moment of shifting from the filling step to the holding step, thereby ensuring the stabilization in quality of molded products. In the filling step, the screw is advanced from the charging finish point at a predetermined speed while renewing the positioning command at time intervals. Simultaneously, the position of screw is monitored to see if it has reached the holding initiating point. When the screw has reached the holding initiating point, the holding step is initiated, and the next positioning command is switched from the present positioning command into one wherein a predetermined value of correction is added to the present positioning command, thereby decelerating (or moving back) the screw. After shifted to the holding step, the position of screw is controlled while renewing the positioning command at time intervals.
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