Injection molding method and control system for injection molding machines
First Claim
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1. A method of injection molding, said method comprising the steps of:
- melting molten resin within a heating cylinder;
advancing an injection screw within the heating cylinder to inject the molten resin into a mold;
retracting the injection screw to a predetermined position before completion of the injection under velocity control;
further advancing the injection screw under pressure control.
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Abstract
An injection molding method comprises the steps of melting molten resin within a heating cylinder, advancing an injection screw within the heating cylinder to inject the molten resin into a mold, retracting the injection screw to a predetermined position before completion of the injection, further advancing the injection screw under pressure control.
15 Citations
30 Claims
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1. A method of injection molding, said method comprising the steps of:
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melting molten resin within a heating cylinder;
advancing an injection screw within the heating cylinder to inject the molten resin into a mold;
retracting the injection screw to a predetermined position before completion of the injection under velocity control;
further advancing the injection screw under pressure control. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An injection molding machine control system, said system comprising:
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a velocity control system, said velocity control system comprising a position detecting unit for detecting a position of an injection screw, a position setting unit for providing a set value of a position of the injection screw, and a first feedback circuit for outputting a first speed command value to an injection motor based upon a difference between a detected value from the position detecting unit and the set value from the position setting unit;
a pressure control system, said pressure control system comprising a pressure detecting unit for detecting a resin filling pressure, and a pressure setting unit for providing a set value of a filling pressure and a dwelling pressure, and a second feedback circuit for outputting a second speed command value to the injection motor based upon a difference between a detected value from the pressure detecting unit and the set value from the pressure setting unit;
a switching unit for switching between an output of the first feedback circuit and second feedback circuit to provide a selected speed command value to the injection motor;
wherein the velocity control system is configured to perform a control action for returning the injection screw to a set position at a predetermined velocity when the injection screw has advanced to a predetermined position during a filling process, and wherein the switching unit switches to the second feedback circuit thereafter. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An injection molding machine control system, said system comprising:
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velocity control means for controlling an injection screw based on velocity control, said velocity control means comprising position detecting means for detecting a position of the injection screw, position setting means for providing a set value of a position of the injection screw, and first feedback means for outputting a first speed command value to an injection motor based upon a difference between a detected value from the position detecting unit and the set value from the position setting means;
pressure control means for controlling the injection screw by pressure control, said pressure control means comprising pressure detecting means for detecting a resin filling pressure, and pressure setting means for providing a set value of a filling pressure and a dwelling pressure, and second feedback means for outputting a second speed command value to the injection motor based upon a difference between a detected value from the pressure detecting means and the set value from the pressure setting means;
switching means for switching between an output of the first feedback means and second feedback means to provide a selected speed command value to the injection motor;
wherein the velocity control means is configured to perform a control action for returning the injection screw to a set position at a predetermined velocity when the injection screw has advanced to a predetermined position during a filling process, and wherein the switching means switches to the second feedback means thereafter. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification