Ultrasonic measurement of residual wall thickness during gas assisted injection molding |
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| Authors: | E.C. Brown L. Mulvaney‐Johnson P.D. Coates |
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| Affiliation: | 1. IRC in Polymer Science and Technology, School of Engineering, Design and Technology, University of Bradford, Bradford, BD7 1DP, UKIRC in Polymer Science and Technology, School of Engineering, Design and Technology, University of Bradford, Bradford, BD7 1DP, UK;2. IRC in Polymer Science and Technology, School of Engineering, Design and Technology, University of Bradford, Bradford, BD7 1DP, UK |
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| Abstract: | Ultrasonic technology provides a powerful and noninvasive method of in‐process measurement during injection molding and extrusion. Changes in the velocity, attenuation and reflection coefficients of high frequency sound waves can be related to the state and conditions of the materials through which they propagate. The velocity of an ultrasonic wave changes with density and elastic moduli; this allows information on solidification and material properties to be collected during the molding cycle. The time of flight of the wave is a function of velocity and path length. This paper shows that it can be correlated with the residual wall thickness of polymer in the mold during gas assisted injection molding. POLYM. ENG. SCI., 47:1730–1739, 2007. © 2007 Society of Plastics Engineers |
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