## 3 Results and Discussions
### Analysis of Variance
#### 3.2.2 Analysis of Variance Experimental Data for AA5083/Coal Composite  
1. Ranking of Contributing Factors  
An analysis of the factors affecting each response element of the fabricated AA5083/Coal composite joint was also carried out. The results shows that the resulting tensile strength of the fabricated AA5083/Coal composite joint is influenced by the tilt angle (rank 1), traverse speed (rank 2), and rotation speed (rank 3), as seen in Table 14. The percentage elongation and microhardness of the fabricated AA5083/Coal composite joint are influenced by the rotation speed (rank 1), tilt angle (rank 2), and traverse speed (rank 3), as indicated by Tables 15 and 16. Based on the results, it can be observed that parameters for maximizing ultimate tensile strength, percentage elongation, and tilt angle in AA5083/Coal composite joints are traversal speed at level 3, rotational speed at level 2, and tilt angle at level 3 as seen in Tables 14-16. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Source** & **Degree of Freedom (DF)** & **Seq SS** & **F-Value** & \(p\)**-Value** &
\begin{tabular}{c} **Percentage** \\ **Contribution** \\ \end{tabular} \\ \hline TS (mm/min) & 2 & 0.05777 & 4.25 & 0.191 & 27.40 \\ RS (ppm) & 2 & 0.10103 & 7.39 & 0.119 & **48.17** \\ TA (\({}^{\circ}\)) & 2 & 0.03729 & 2.73 & 0.268 & 17.78 \\ Error & 2 & 0.01367 & & & 6.452 \\ Total & 8 & 0.20975 & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Contribution of individual factor to the variation of microhardness. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Source** & **Degree of Freedom (DF)** & **Seq SS** & **F-Value** & \(p\)**-Value** &
\begin{tabular}{c} **Percentage** \\ **Contribution** \\ \end{tabular} \\ \hline TS (mm/min) & 2 & 9.9970 & 0.61 & 0.621 & 11.32 \\ RS (ppm) & 2 & 50.823 & 3.10 & 0.244 & **57.55** \\ TA (\({}^{\circ}\)) & 2 & 11.110 & 0.68 & 0.596 & 12.58 \\ Error & 2 & 16.379 & & & 18.55 \\ Total & 8 & 88.308 & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Contribution of individual factor to the variation of ultimate tensile strength. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Source** & **Degree of Freedom (DF)** & **Seq SS** & **F-Value** & \(p\)**-Value** &
\begin{tabular}{c} **Percentage** \\ **Contribution** \\ \end{tabular} \\ \hline TS (mm/min) & 2 & 9.9970 & 0.61 & 0.621 & 11.32 \\ RS (ppm) & 2 & 50.823 & 3.10 & 0.244 & **57.55** \\ TA (\({}^{\circ}\)) & 2 & 11.110 & 0.68 & 0.596 & 12.58 \\ Error & 2 & 16.379 & & & 18.55 \\ Total & 8 & 88.308 & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Contribution of individual factor to the variation of percentage elongation. 2. Percentage of Contribution Factors  
The percentage contributions by S/N ratio analysis of variance for microhardnessness, elongation percentage, and ultimate tensile strength are displayed in Tables 17-19. Based on the results, the most significant factors influencing ultimate tensile strength are tilt angle and traverse speed, which accounted for 27.0% and 19.3% respectively, of the output response (see Table 17). These results are consistent with the ranks that were shown in Table 14. It was discovered that rotational speed and tilt angle, with percentage contributions of 34.4% and 30.0%, respectively, were significant parameters for percentage elongation (see Table 18). These results are consistent with the ranks that were shown in Table 15. The most significant factor influencing microhardnessness was determined to be rotational speed, which accounted for 44.89% of the output response. Though less significant, tilt angle nonetheless made 9.131% of the total (see Table 19). These results are consistent with the ranks that were shown in Table 16. Research by [PERSON] et al. [26], [PERSON] et al. [35], and [PERSON] et al. [45] also showed a similar pattern, identifying tool rotational speed as the main factor influencing microhardness. The percentage contributions for ultimate tensile strength, percentage elongation, and microhardness match the rankings and the F-values.