The current approach for surface-critical injection molded thermoplastic automotive parts such as bumpers is to paint them. Before painting, in order to ensure proper adhesion between the plastic part and the paint, an adhesion promoter is sprayed on the parts (priming). These two processes are expensive and environmentally unfriendly. 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 located such that total coverage is achieved and the potential for air trapping is minimized. The selected location should be cosmetically and be accessible for ease of maintenance.;In this research work, the mathematical model for one-dimensional IMC flow with the slip boundary condition and power law rheological model has been developed first to illustrate the effect of slip on the pressure distribution and serves as a basis for further modifications to be undertaken to predict pressures accurately. Taking a step further, 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 HeleShaw 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. It was found that they predicted pressures as well as fill patterns more accurately than power law and no-slip boundary condition based software. (Abstract shortened by UMI.).
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