Optical Monitoring of Polypropylene Injection Molding

Abstract

We have developed a model to describe the behavior of an optical fiber sensor for monitoring injection molding. The sensor was used to detect light reflected from the mold cavity during the packing and cooling phases of injection molding of polypropylene. Light which reflected off the opposite wall of the mold and back to the optical fiber was analyzed for information regarding crystallization kinetics and the amount of crystallinity in the final product. The model illustrates how temperature, pressure and crystallinity affect the detected light intensity.