Injection Molding Simulation of Polyoxymethylene Using Crystallization Kinetics Data and Comparison with the Experimental Process

Abstract

It is well known that the processing conditions in polymer processing have a high impact on the resulting material morphology and consequently the component’s mechanical behavior. However, especially for semicrystalline polymers, the tools available for predicting the final morphology of injection molding parts still have significant limitations. In order to investigate the potential of injection molding simulation for the prediction of the morphology, POM homopolymer specimens were injection molded. The crystallization kinetics data were measured, and simulations in 3D and 2.5D with and without crystallization analysis were conducted in Autodesk Moldflow. The simulations are found to be good accordance with the experiments. Predicted spherulite size and crystalline orientation factor reveal a good qualitative correlation with optical micrographs. Also, the evolution of these parameters along the flow path is plausible. The simulation is found to be a powerful tool for morphology prediction in polymeric parts. Its applicability, however, is still limited to 2.5D models in Autodesk Moldflow, which, of course, is insufficient for complex, thick-walled 3-dimensional parts.

Rheological Behavior Features of Feedstocks with a Two-Component Wax–Polyolefin Binder Compared to Analogs Based on Polyoxymethylene

“…[26,27] presented models for simulation modeling of feedstock casting processes with a common type of binder based on a wax-polyolefin mixture, and many other works presented data on the rheological state of feedstocks with another common type of binder, polyoxymethylene, also used for modeling casting processes. In addition, in the field of feedstocks with a polyoxymethylene-based binder, it is necessary to note the works [28,29], which not only describe the characteristics of the materials under study but also show that for POM copolymers and their mixtures, the relationship between complex viscosity and rotational viscosity can be correctly described using the Cox-Merz rule. However, it should be noted that for highly filled feedstocks, the Cox-Merz rule is not valid, even when it is valid for the binder materials.…”