PURPOSE: To reduce the loss of a resin material to be extruded to enhance the production efficiency of blow molding by comparing the value of a residual resin after a resin discharge process with a preset value by a specific control system.
CONSTITUTION: The position of a discharge piston at the end of a resin discharge process is measured by a position transmitter 11 to be sent to the evaluation circuit 16 within a control system 15. In the evaluation circuit 16, the inflow amt. signal value measured at the end of the discharge process is substracted from the set value related to the final position to calculate an actual residual resin amt. The actual residual resin amt. is inputted to a comparison stage 28 to be compared with the set value set to a memory element 29 to calculate a difference signal. This difference signal is sent to a difference integration adjusting device 34 to be sent to an extruder actuator 3 through a digital/ analogue converter 27 and a rotational speed for extruding a resin is adjusted in order to allow the residual amt. of the resin to approach the set value.
HAINRITSUHI BERUGUMAN
BUORUFUGANGU NUN
