Abstract: A method controlling the afterpressure variation with time of an injection-moulding machine. A process computer controlling a hydraulic pressure drive of the injection-moulding machine stores a given reference afterpressure variation with time. Upon a variation of the moulding mass temperature Tm and/or of the tool temperature Tf, a new afterpressure variation with time is calculated. The time data samples corresponding to the reference temperature values and the reference afterpressure values, respectively, are then determined.

Abstract: The invention relates to a blow molding machine for the blow molding of hollow articles, with an accumulator head (1) for producing a preform and with a blow mold for forming a hollow article from the preform. After completion of a blow molding sequence, a piston positioning signal is derived by a control system (15), to regulate the position of a discharge piston (4) in the accumulator head (1), from a comparative signal of the actual position and set position of the discharge piston (4). The set position is determined by integration from a previously specified speed set point profile. The control system (15) further superimposes an influx signal on the comparative signal, which corresponds to the change in volume of plastic flowing from an extruder (2) to replace the discharged contents of the accumulator head (1).

Abstract: A blow molding machine for the blow molding of hollow articles includes an accumulator head (1) for producing a preform and a blow mold for forming a hollow article from the preform. After completion of a blow molding sequence and the filling of the accumulator head (1), a piston positioning signal is sent by a control system (15) to regulate the position of a discharge piston (4) in the accumulator head (1) derived from a comparative signal of the actual position and set position of the discharge piston (4). The set position is determined by integration from a previously specified speed set point profile. The control system (15) further superimposes an influx signal on the comparative signal, which corresponds to the change in volume of plastic flowing from an extruder (2) to replace the discharged contents of the accumulator head (1).

Abstract: A control arrangement for moving tools brings these tools quickly into a desired position smoothly and without shock. The arrangement comprises means for preadjusting the required displacement so that the whole displacement path corresponding to the movement sweep of the tool is first determined. A calculation member (4) converts a given delay of the tool movement into a value corresponding to the speed of movement. An integrator (6) derives from the calculated speed value as a function of time a required position value. Upon movement of the tool the means for preadjusting the required displacement are continuously readjusted and the adjusted value for the drive (25) is determined by means of a comparison with the position value supplied by the actual displacement pick-up device (8).