Effect of fiber content and wall slip phenomenon on the polymer filling behavior in thermoset injection molding and simulation process
Final Report Abstract
A completely opposite injection molding filling behavior of thermosets and thermoplastics was found by using an effective and useful method. Specifically, for the thermoset injection molding, there is a strong slip between the thermoset melt and wall surface, which is not found for the injection molding of thermoplastic materials. The slip phenomenon of phenolic thermoset injection molding compounds is strongly dependent on the filler amount, the injection speed, the mold temperature, and the surface roughness. A lower filler amount and injection speed and a higher mold temperature and surface roughness decrease the wall slip phenomenon of the thermoset melts. Consequently, the thicknesses of the oriented fiber under the surface of molded parts increase significantly. The received results are background knowledge for subsequent studies in the field of thermoset injection molding, such as the theoretical foundations of the calculation, analysis, and simulation fiber orientation in the filling phase of the injection molding process with consideration of the wall slip phenomenon. The fitting tool called Thermoset – TU – Fitting tool has been developed to investigate and evaluate the adaptation of different reactive viscosity models and cure kinetics models in the viscosity and curing kinetics characterization of reactive injection molding materials. The material properties of commercial thermoset materials for the simulation processes of reactive injection molding were successful created with the optimal cure kinetics and reactive viscosity model. Thermoset – TU – Fitting tool is now a package available to all the scientific and industrial community through Professorship of Plastics Engineering, TU Chemnitz. The generated material properties were directly employed to simulate the mold filling behavior of highly filled thermoset injection molding compounds such as the weld line formation, the reactive viscosity behavior, the cavity pressure profile and the temperature distribution. For the thermoset injection molding compounds with the filler content of less than 65% like PF6680, PF6506 and Vyncolit X6320, the effect of wall slip phenomenon and the processing conditions on the mechanism of the weld line formation is slight and could be neglected. The form filling behavior of these materials was successfully simulated. However, for the thermoset injection molding compounds with the filler content of more than 65% like PF1110, the wall slip phenomenon, the mold temperature and the injection speed have a great impact on the mold filling characterization such as the formation and development of weld lines, the compacted zone, the uncompacted zone and the pressure gradient and the curing behavior in the filling process, which has not yet been accurately simulated by the commercial simulation software. These problems are now leading to a real challenge for the fluid dynamic simulation tool.
Publications
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„Bewertung der aktuellen eingesetzten reaktiven Viskositätsmodelle zur rheologischen Simulation im Spritzgießprozess,“ in Technomer Fachtagung über Verarbeitung und Anwendung von Polymeren, Chemnitz, 2021.
Tran, Ngoc Tu & Gehde, Michael
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„Modelling of rheological and thermal properties for reactive injection molding simulation process (the full article has been accepted for publication),“ AIP Publisher Conference Proceedings (37th International Conference of the Polymer Processing Society, Fukuoka, Japan), 2022.
Tran, Ngoc Tu & Gehde, Michael
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„Modelling of rheological and thermal properties for reactive injection molding simulation process, “PPS37, 37th International Conference of the Polymer Processing Society, Fukuoka, Japan, 2022.
Tran, Ngoc Tu & Gehde, Michael
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Flow Disturbance Characterization of Highly Filled Thermoset Injection Molding Compounds behind an Obstacle and in a Spiral Flow Part. Polymers, 15(14), 2984.
Tran, Ngoc Tu; Seefried, Andreas; Gehde, Michael; Hirz, Jan & Klaas, Dietmar
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Investigation of the Influence of Fiber Content, Processing Conditions and Surface Roughness on the Polymer Filling Behavior in Thermoset Injection Molding. Polymers, 15(5), 1244.
Tran, Ngoc Tu; Seefried, Andreas & Gehde, Michael
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„Vorhersage der reaktiven Viskosität und des Vernetzungsverhaltens von duroplastischen Spritzgießmassen,“ in Technomer Fachtagung über Verarbeitung und Anwendung von Polymeren, Chemnitz, 2023.
Tran, Ngoc Tu; Seefried, Andreas & Gehde, Michael
