## 2 Materials and Methods
### Specim of Tensile Test Preparation and Testing Methods  
Figure 2 depicts the preparation process for tensile test specimens. A flat plate was first produced via injection molding, after which specimens were precisely machined using CNC equipment to prevent processing-induced damage. Tensile specimens were extracted at orientations of 0\({}^{\circ}\) (parallel to the flow direction), 45\({}^{\circ}\), and 90\({}^{\circ}\) relative to the injection flow.  
Figure 3 shows the heating zones within the cylinder of the injection molding machine, configured according to the conditions listed in Table 2. Table 2 details the molding parameters for the flat plate mold. NH (Nozzle Heating) indicates the nozzle temperature, while H1, H2, and H3 correspond to the temperatures of sequential zones within the cylinder, with H1 being closest to the nozzle. The molding conditions were optimized to minimize deformation of the molded plates. Injection molding was primarily controlled by time, with pressure and speed set as percentages of the equipment's maximum capacity rather than absolute values. These settings--typically between 80% and 90%--were used to determine actual pressure and speed values, which were back-calculated based on the predefined injection time. Real-time monitoring of the molding behavior was performed using pressure gauges installed on the equipment. The same control strategy was applied in the process simulation, where injection time was fixed and holding pressure was defined as a percentage of the calculated injection pressure, ensuring consistency between experimental and simulated conditions.  
A total of 20 flat plates were fabricated. Based on surface quality and dimensional consistency, 10 plates were selected for specimen preparation. From each selected plate, tensile specimens were machined at orientations of 0\({}^{\circ}\), 45\({}^{\circ}\), and 90\({}^{\circ}\) relative to the flow direction using CNC equipment to prevent processing damage. For each condition, five replicate tensile tests were conducted, and the average values were used for analysis.  
Figure 1: Rheological and PVT characteristics of PA66/GF50 (wt%).  
Figure 2: Tensile testing according to fiber orientation.  
To prepare dumbbell-shaped specimens for tensile testing, flat-shaped models (180 \(\times\) 180 \(\times\) 4 mm) were used to produce specimens oriented at 0\({}^{\circ}\), 45\({}^{\circ}\), and 90\({}^{\circ}\) with respect to the injection flow direction. Figure 4 presents the geometry of the tensile specimens used in accordance with the ASTM D638M standard [22]. The dimensional specifications of the specimens are provided in Table 3, while the tensile test conditions are detailed separately in Table 4. Figure 4a shows a photograph of the tensile specimen, and Figure 4b illustrates the schematic drawing of the specimen. For each orientation, five replicate tensile tests were conducted, and the average values were used for analysis.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Specimen** & \(b_{1}\) & \(b_{2}\) & \(h\) & \(L_{3}\) & \(L\) & \(t\) & \(A\) \\ \cline{2-7}
**Dimension** & 9.86 & 19.82 & 3.92 & 172.64 & 115 & 3 & 38.65 mm\({}^{2}\) \\ \hline \hline \end{tabular}
\end{table}
Table 4: Tensile test conditions.  
Figure 3: Schematic of the injection molding screw and barrel configuration with designated heating zones. NH represents the nozzle heater, while H1–H3 denote the sequential barrel heating zones used to control the temperature during polymer melting and transport.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{4}{c}{**Cylinder Head Temperature (\({}^{\circ}\)C)**} & \multicolumn{4}{c}{**Injection Molding Conditions**} \\ \hline NH & H1 & H2 & H3 & Pressure (\%) & Time (s) \\ \hline
315 & 310 & 290 & 280 & 80 & 4 \\ \hline \hline \multicolumn{4}{c}{Holding Pressure Conditions} \\ \hline  & & & Pressure (\%) & Time (s) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Injection molding process conditions.