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Modeling and experimental verification of pressure prediction in the in-mold coating process for thermoplastic substrates

Bhagavatula, Narayan L
http://rave.ohiolink.edu/etdc/view?acc_num=osu1145371989

Abstract Details

2006, Doctor of Philosophy, Ohio State University, Industrial and Systems Engineering.
In-mold coating (IMC) process has emerged as a low cost and environmentally friendly alternative to painting and priming processes. Due to its successful application to exterior body panels made from compression molded Sheet Molding Compound (SMC), IMC is being developed as a technology that would ultimately replace painting of injection molded thermoplastic parts. In the short term,however, we believe IMC has the potential of being a substitute to primer.There are key issues that need to be addressed for a successful IMC operation.The location of IMC nozzle should be such that total coverage is achieved,the potential for air trapping is minimized and is accessible for ease of maintenance. This necessitates the use of fill patterns. To avoid leakage of the coating material, the generated hydraulic force must never exceed the clamping force. Therefore it is imperative that we predict the pressures generated during coating injection. Existing prediction tools based on the Hele-Shaw approximation, assuming the coating to be a power law fluid and using the traditional no-slip boundary condition adequately predict the fill patterns but do not predict pressures correctly. This deviation has been partly attributed to slip at the wall, as often found in flow through micro channels. Further, research has shown evidence of an upper Newtonian plateau for the coating viscosity at high shear rates. In this research work, a one-dimensional mathematical model including an advanced rheological model in the form of Sisko and Carreau models, in addition to the slip boundary condition has been developed and solved numerically using FDM. Coating thickness is predicted as a function of location and time. This model validates the approach of using slip and improved rheological equations in IMC flow modeling to predict pressures accurately.The model is further extended to a two-dimensional simulation tool based on the Hele-Shaw approximation, in order to simulate coating flows over more complex geometries. The compressibility of the substrate is described by the modified double domain Tait PVT model. CV/FEM is applied to solve the governing equations. The developed simulation tools are verified based on existing 2D experimental results obtained using the IMC pilot facility, as well as new results based on constant flow rate experiments.
Jose Castro (Advisor)
155 p.
In-Mold coating; flow simulation; control volume

Recommended Citations

Citations

  • Bhagavatula, N. L. (2006). Modeling and experimental verification of pressure prediction in the in-mold coating process for thermoplastic substrates [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1145371989

    APA Style (7th edition)

  • Bhagavatula, Narayan. Modeling and experimental verification of pressure prediction in the in-mold coating process for thermoplastic substrates. 2006. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1145371989.

    MLA Style (8th edition)

  • Bhagavatula, Narayan. "Modeling and experimental verification of pressure prediction in the in-mold coating process for thermoplastic substrates." Doctoral dissertation, Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1145371989

    Chicago Manual of Style (17th edition)

osu1145371989
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© 2006, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.