## 7 Conclusions and Outlook  
The flow front contours in Figures 8 and 9 show that most rheological models reproduce the flow behavior on a similar accuracy level. However, the Second-Order model differs significantly in the edge region of the flow front from the other models and the experimental results. While the rheological models in the middle region of the flow front come close to the experimental values at the time of 0.26 s, they are slightly ahead of the experiments at the time of 0.32 s. This shows that the rheological models approximate the experiments well in the middle region of the flow front, but run slightly ahead in the wall region. This effect results form the lack of modeling of the back pressure in the cavity and the associated \(pvT\)-relationships. The real flow front of the experiments is not perfectly symmetrical, which is due to slight asymmetries in the temperature distribution of the mold, surface roughness and manufacturing tolerances. The Carreau-WLF Winter model shows the best approximation to the wall region compared to the other models. This \begin{table}
\begin{tabular}{c c c} \hline \hline
**Viscosity Model** & **Shear Rate** & **Temperature** \\ \hline Power-Law & \(\surd\) & no \\ Second-Order & \(\surd\) & \(\surd\) \\ Herschel-Bulkley & \(\surd\) & no \\ Carreau & \(\surd\) & no \\ Carreau-WLF & \(\surd\) & \(\surd\) \\ Carreau Winter & \(\surd\) & no \\ Carreau-WLF Winter & \(\surd\) & \(\surd\) \\ Bird-Carreau & \(\surd\) & no \\ Cross & \(\surd\) & no \\ Cross-WLF & \(\surd\) & \(\surd\) \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Overview of the rheological models and their influencing variables. observation confirms similar research findings that highlight the enhanced capability of the Carreau-WLF Winter model in modeling temperature-dependent viscosity effects during injection molding simulations [5; 6]. The RMSE values presented in Table 6 confirm these observations. The Carreau-WLF Winter model provides the most accurate prediction of the flow, as indicated by the lowest RMSE values. The Carreau model and the Power-Law model follow with moderate RMSE values, while the Second-Order model has the highest RMSE values and thus the lowest accuracy. These RMSE values are in strong agreement with the visual results, which underlines the significant deviation in the edge region of the Second-Order model and the optimal approximation of the Carreau-WLF Winter model. The analysis of the variables that influence viscosity indicates that all models are dependent on shear rate. This implies that viscosity decreases as shear rate increases. In addition, the Second-Order, Carreau-WLF, Carreau-WLF Winter, and Cross-WLF models exhibit a temperature-dependent viscosity, whereby the viscosity decreases with increasing temperature. The models allow for a differentiated adjustment of the viscosity under varying process conditions, whereas the other models remain less sensitive to temperature changes. Although all models demonstrate a comprehensible viscosity distribution influenced by the shear rate and temperature, there are slight differences in the middle region. The viscosity in the wall and sprue region is less than that observed in the middle region. However, the middle region shows notable differences. While the Carreau models depict a relatively homogeneous viscosity distribution, the middle region shows a significantly more heterogeneous viscosity distribution in the other rheological models. The real viscosity cannot be definitively determined at this point. This would require the development of innovative measurement techniques that can accurately quantify viscosity within the cavity. All rheological models demonstrate a comparable characteristic of the flow front, which indicates that the shear rate is the dominant factor in this context. The viscosity versus shear rate in Figures 3-5 and the mathematical approximations of the rheological models do not directly indicate this context.