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Publication Citation: In-Situ Monitoring of Product Shrinkage During Injection Molding Using an Optical Sensor

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Author(s): C L. Thomas; Anthony J. Bur;
Title: In-Situ Monitoring of Product Shrinkage During Injection Molding Using an Optical Sensor
Published: January 01, 1999
Abstract: We have used an optical fiber sensor for in-situ monitoring of product shrinkage during injection molding. The sensor, consisting of a bundle of optical fibers with a sapphire window at its end, is positioned in the ejector pin channel of the mold so that the sapphire window sits flush with the inside cavity wall. When the molded product shrinks, it separates from the wall and sapphire window, and establishes the geometry of a Fabry-Perot interferometer. During the molding of polystyrene, polypropylene and polyethylene, we observed optical interference fringes, and by counting fringes, a measurement of shrinkage was made.
Conference: Society of Plastics Engineers. Technical Meeting
Proceedings: Proceedings of the Society of Plastics Engineers Annual Technical Meeting
Volume: 86
Location: New York, NY
Dates: May 1, 1999
Keywords: injection molding;interferometer;optical fiber sensor;polyethylene;polypropylene;polystyrene;process monitoring;shrinkage
Research Areas: Polymers
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