Multivariate shrinkage sensor (MVSS) for injection molding
AssigneeLeonine Technologies Inc.
InventorRahul R. Panchal
Life of this patent
Estimating the term…
Abstract
A shrinkage detection device for a polymer injection molding apparatus detects a shrinkage experienced by an injection molded element for assessing a quality of the molded element. Shrinkage, along with temperature and pressure of the melt within the mold during cooling, indicates a sufficiency of the resulting molded element for intended purposes. Sufficiency includes parameters such as flexibility, shear strength and longevity, and is accurately performed can replace conventional sample testing of molded articles that are expensive and time consuming.
Claims17
An injection molding quality sensing device, comprising:
- an elongated plunger in communication with a cavity defined by an interior volume of a mold, the elongated plunger having a distal end in communication with the cavity and a proximate end responsive to a biasing force;
- a magnetic source attached to the proximate end;
- and
- a position sensor responsive to the magnetic source for
- detecting a movement of the plunger based on displacement of the distal end from shrinkage of an injected melt contained in the cavity;
- and
- generating a displacement signal indicative of the shrinkage;
- a temperature sensor disposed in the distal end of the elongated plunger, the temperature sensor having an infrared lens for passing radiated energy frim the melt for generating a melt temperature signal based on a temperature of the injected melt;
- and
- an analysis circuit configured to generate a validation signal based on the displacement signal and the melt temperature signal.
A method of validating an injection molded article resulting from injection of a melt into a mold, comprising:
- extending an elongated plunger into cavity defined by an interior volume of a mold, the elongated plunger having a distal end in communication with the cavity and a proximate end responsive to a biasing force;
- injecting a melt defined by a molding substance into the cavity via a fluidic interface;
- retracting the elongated plunger back from the cavity responsive to a pressure of the injected melt, the pressure of the injected melt detected by a pressure sensor on the elongated plunger;
- measuring the detected pressure from the pressure sensor when the elongated plunger retracts such that the distal end is flush with an interior surface of the mold;
- and
- measuring a displacement distance based on the position signal when the detected pressure abates for indicating a cooled melt in the cavity;
- measuring a melt temperature from a temperature sensor disposed in the distal end of the elongated plunger, the temperature sensor having an infrared lens for passing radiated energy frim the melt based on a temperature of the injected melt;
- and
- generating a validation signal indicative of a quality of the molded article based on the detected pressure, the displacement distance and the melt temperature.
Dependencies are inferred from the claim text.