Browsing by Author "Patcharee Larpsuriyakul"

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Open Access
Design, analysis and simulation in injection in-mold labeling
(2009) Patcharee Larpsuriyakul; Fritz, Hans-Gerhard (Prof. Dr.-Ing.)
Years ago, the production of packaging with the injection-IML has been established. This procedure concept ranks nowadays among the most modern technologies in the area of the plastic packaging. With this manufacturing technique, label and packaging, both are of the same polymer materials, become inseparably connected during the injection molding process. Since thermal conductivity of the polymeric label material is clearly smaller than that of the metal mold wall, thermal induced warpage of injected IML part or part surface deformation could be occurred. The objective of this work is to analyze and simulate the filling, holding, and cooling phases of the injection IML process by means of the simulation program Moldex3D® and to study the effect of inserted label on the warpage behavior and modulus of elasticity of injected parts. For this study, the injection mold for injection IML equipped with vacuum ports for holding the label was designed and constructed. For the automation of the injection IML process, a linear pneumatic robot was employed. As a preliminary examination, the experimental study and numerical simulation of the melt front advancement, course of the pressure and melt temperature profile during the injection molding of double-plated parts with non-uniform part thickness were done in order to acquire better understanding of the simulation program Moldex3D® prior to its application later on to the injection IML simulation calculations. The molded part composes of two thin plates joined together with a cold runner. One fan gate is connected to the thick side of the first plate and the other connected to the thin side of the second plate. Comparisons between the experiment and simulation performed with the same molding parameters were carried out. From the results, 2.5D simulation was verified to be more reliable than 3D simulation particularly in terms of predicting the melt front advancement as well as the melt pressure development during the molding. Owing to the complex flow and unbalance of the pressure within two cavities of the part, 3D simulation based on non-isothermal computation failed to predict course of the pressure and hence the melt front advancement within both cavities. However, with the 3D isothermal computation, improvement in accuracy was achieved. This phenomenon resulted from the instability of the 3D simulation program. By molding the double-plated part separately, both 2.5D and 3D simulation results agreed well with those from the experiments. After the preliminary examination has been done, analysis and 3D simulation on filling, holding, and cooling phases of the injection IML process and warpage behavior of injected IML parts were investigated, since the presence of label can significantly affect the molding process. From the study, good agreement of the mold filling, holding, and cooling results between 3D simulation and experiment was acquired. Structure and warpage behavior of IML parts were also investigated. In order to cope with part warpage problem, variations in mold temperature on the stationary and moving mold halves were carried out. With the higher mold temperature setting on the label side, part warpage was reduced. Furthermore, study of the effect of the mold temperature combination settings on the modulus of elasticity of the IML part was conducted. The results revealed that despite a slight reduction in the modulus of elasticity of the IML part owing to the different mold temperature settings on two mold halves, modulus of elasticity of the IML part was still found to be satisfactory.