Department of Mechanical Engineering

“Core Deflection and Flash in Injection Molding”

 

Mechanical Engineering Seminar

Thursday, January 18, 2007
10:00 – 10:50 AM
3004/06 Black Engineering

A. Jeffrey Giacomin
Chair, Rheology Research Center
Professor of Mechanical Engineering
University of Wisconsin – Madison

“Core Deflection and Flash in Injection Molding”

Abstract This lecture attacks two hard nuts to crack in plastics injection molding. First, a general problem called flash arising when polymer seeps between mold parting surfaces to form an unsightly paper-thin edge around the part. Here, a race between polymer solidification and pressure driven slit flow arises. Second, a problem specific to the injection molding of long slender products such as test tubes is addressed. Called core deflection, here the solid steel core forming the inside of the test tube is prone to bending, causing tube bend. The underlying momentum transport governing both problems is addressed, uncovering two new dimensionless groups for plastics engineering: flashability and deflectability.BiographyProfessor Giacomin's research group explores the role played by rheology in plastics processing. He and his students have published more than 50 journal articles on blow molding, pipe extrusion, wire coating, sheet coating, cellulose fiber filled materials, ultrasonic property measurement, sliding plate rheometry and on the nonlinear viscoelasticity of molten plastics and cheese. He currently is an Associate Editor for the Journal of Rheology, and chairs the executive committee of the Rheology Research Center at the University of Wisconsin – Madison.For questions, contact Charlene Kravinsky (cakravi@iastate.edu)

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