Novel Analysis Methodology for High-Pressure Physical Microcellular Foaming Injection Molding based on Phase Diagram of Physical Blowing Agent and Melt Element Tracing Simulation

Microcellular foaming utilizing highly pressurized physical blowing agent (PBA) is widely employed for the injection molding of lightweight, high-dimensional-quality parts. The cell foaming behavior is important for the quality of foam injection-molded parts, and the physical condition of the PBA provides crucial information on cell growth. In this study, the pressure-temperature (PT) history of melt elements is directly compared with the phase diagram of the PBA to propose a novel method that analyzes the simulation results of microcellular injection molding. The PT history of particle tracers from different final positions exhibited unique profiles, particularly in relation to the thickness and flow length directions. Each PT history can be directly correlated to the phase change of the PBA and is useful for understanding positional differences in cell growth conditions.