Alex M. Watt



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Polymer extrusion is a manufacturing process of forcing a melted plastic through a die to create a continuous part with a constant cross-section dictated by the die’s geometry. The typical process uses a fixed die that creates high output at low cost when compared to injection molding. The overarching goal of this project is to develop dies capable of changing cross sectional area during the extrusion process. Preliminary dies have been designed, created and operated in a production process. In order to test the shape repeatability of these dies, a laser scanner was used to capture cross sections at numerous locations along the resulting parts. A numerical process was then developed to accept the data from the scanner and create a representation of the profile. These profiles were then compared to the profiles at other locations. The repeatability of the sections from these variable geometry parts has been found to be similar to fixed-geometry parts. Further, the extruded parts have also been compared to the die exit geometry to examine expansion that occurs during the process.

Publication Date


Project Designation

Independent Research

Primary Advisor

Andrew P. Murray, David H. Myszka

Primary Advisor's Department

Mechanical and Aerospace Engineering


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Assessing Shape Repeatability in Variable Geometry, Polymer Extrusion Dies