Method for controlling the forward movement speed of the screw in an injection molding machine

A method for controlling a forward movement speed of a screw in an injection molding machine in which a molten resin stored in a heating barrel is fed into a mold by advancing the screw within the heating barrel, comprising:

• controlling the forward movement speed of the screw in accordance with a predetermined speed pattern after the initiation of the forward movement until the screw reaches a predetermined deceleration initiation point;
• measuring an internal pressure of the mold and controlling the forward movement speed of the screw in a feedback control manner such that the internal pressure reaches a predetermined pressure, after the screw reaches the deceleration initiation point, until the time elapsed from the initiation of the forward movement of the screw reaches a predetermined pressure holding initiation time, said feedback control being performed using a first set of PID coefficients;
• and
• measuring the internal pressure of the mold and controlling the forward movement speed of the screw in a feedback control manner such that the internal pressure of the mold changes in accordance with a predetermined pattern of target pressure versus time, after the time elapsed from the initiation of forward movement of the screw reaches the pressure holding initiation time, said feedback control being performed using a second set of PID coefficients.

A method for controlling a forward movement speed of a screw in an injection molding machine in which a molten resin stored in a heating barrel is fed into a mold by advancing the screw within the heating barrel, comprising:

• controlling the forward movement speed of the screw in accordance with a predetermined speed pattern after the initiation of the forward movement until the screw reaches a predetermined deceleration initiation point;
• measuring an internal pressure of the mold at a plurality of points within the mold and controlling the forward movement speed of the screw in a feedback control manner such that the highest of internal pressures thus measured reaches a first target pressure, from the deceleration initiation point to a predetermined pressure holding initiation point, said feedback control being performed using a first set of PID coefficients;
• and
• measuring the internal pressure of the mold at the plurality of points within the mold and controlling the forward movement speed of the screw in a feedback control manner such that the highest internal pressure is maintained at a second target pressure, after the screw reaches the pressure holding initiation point, said feedback control being performed using a second set of PID coefficients.

A method for controlling a forward movement speed of a screw in an injection molding machine in which a molten resin stored in a heating barrel is fed into a mold by advancing the screw within the heating barrel, comprising:

• controlling the forward movement speed of the screw in accordance with a predetermined speed pattern after the initiation of the forward movement until the screw reaches a predetermined deceleration initiation point;
• measuring an internal pressure of the mold at a plurality of points within the mold and controlling the forward movement speed of the screw in a feedback control manner such that the highest of internal pressures thus measured reaches a target pressure, from the deceleration initiation point to a predetermined pressure holding initiation point, said feedback control being performed using a first set of PID coefficients;
• and
• measuring the internal pressure of the mold at the plurality of points within the mold and controlling the forward movement speed of the screw in a feedback control manner such that the highest internal pressure is changed in accordance with a predetermined pattern of target pressure versus time, after the screw reaches the pressure holding initiation point, said feedback control being performed using a second set of PID coefficients.

A method for controlling a forward movement speed of a screw in an injection molding machine in which a molten resin stored in a heating barrel is fed into a mold by advancing the screw within the heating barrel, comprising:

• controlling the forward movement speed of the screw in accordance with a predetermined speed pattern after the initiation of the forward movement until the screw reaches a predetermined deceleration initiation point;
• measuring an internal pressure of the mold at a plurality of points within the mold and controlling the forward movement speed of the screw in a feedback control manner such that the highest of internal pressures thus measured reaches a first target pressure, after the screw reaches the deceleration initiation point, until the time elapsed from the initiation of the forward movement of the screw reaches a predetermined pressure holding initiation time, said feedback control being performed using a first set of PID coefficients;
• and
• measuring the internal pressure of the mold at the plurality of points within the mold and controlling the forward movement speed of the screw in a feedback control manner such that the highest internal pressure is maintained at a second target pressure, after the time elapsed from the initiation of forward movement of the screw reaches the pressure holding initiation time, said feedback control being performed using a second set of PID coefficients.

A method for controlling a forward movement speed of a screw in an injection molding machine in which a molten resin stored in a heating barrel is fed into a mold by advancing the screw within the heating barrel, comprising:

• controlling the forward movement speed of the screw in accordance with a predetermined speed pattern after the initiation of the forward movement until the screw reaches a predetermined deceleration initiation point;
• measuring an internal pressure of the mold at a plurality of points within the mold and controlling the forward movement speed of the screw in a feedback control manner such that the highest of internal pressures thus measured reaches a target pressure, after the screw reaches the deceleration initiation point, until the time elapsed from the initiation of forward movement of the screw reaches a predetermined pressure holding initiation time, said feedback control being performed using a first set of PID coefficients;
• and
• measuring the internal pressure of the mold at the plurality of points within the mold and controlling the forward movement speed of the screw in a feedback control manner such that the highest internal pressure is changed in accordance with a predetermined pattern of target pressure versus time, after the time elapsed from the initiation of forward movement of the screw reaches the pressure holding initiation time, said feedback control being performed using a second set of PID coefficients.