## 5 Conclusions  
In this study, a point cloud value was established as the response variable for the quantitative evaluation of spray deposition quality within the dust plate fabrication process. The principal spray parameters influencing this response were systematically investigated through two distinct series of RSM experiments. In the primary experiment, spray pressure (A), spray speed (B), spray distance (C), and number of sprays (D) were designated as the operational variables. For the supplementary experiment, spray speed (B), which exhibited low statistical significance in the initial phase, was excluded, and spray angle (B) was introduced as a substitute variable to facilitate a more precise analysis of the spatial characteristics pertinent to the resultant surface spray pattern. The primary experiment, based on a high coefficient of determination (R\({}^{2}\approx 97\%\)), demonstrated that spray pressure and number of sprays were the most significant variables. Notably, the quadratic effect of the number of sprays (D\({}^{2}\)) and the interaction between spray distance and number of sprays (CD) highlighted how the balance between cumulative spray volume and spray distance impacts the final spray quality. The results underscore the importance of designing conditions with multivariable interactions, as it is difficult to find optimal conditions by adjusting one variable at a time. The supplementary experiment, despite a somewhat reduced explanatory power (R\({}^{2}\approx 78\%\)), confirmed the effect of a novel spatial variable: the spray angle. Within this experiment, spray pressure again emerged as the most significant variable. The influences of the spray angle and spray distance were mainly indirect, manifesting as quadratic effects with less significant main effects. Specifically, a negative interaction between spray pressure and number of sprays (AC) indicated that high-pressure and long-distance conditions could potentially inhibit the response. The optimal value remained at 3 bar, replicating the result of the primary experiment; this consistency, even after increasing the pressure to 5 bar, demonstrates the reliability and reproducibility of the original study. In conclusion, the main factor affecting process quality is spray pressure, with spray distance and number of sprays being key factors. Spray angle and spray distance functioned as auxiliary variables with indirect influence through quadratic or interaction effects. The results support the need for a multifactor design in the dust-spraying process and a quantitative understanding of the complex effects among variables. This study is particularly significant in that, by experimentally mapping the complex relationships among variables, it provides fundamental insights and practical technical groundwork essential for achieving precise control over the dust-spraying process and for developing automation systems. Moreover, these findings offer valuable implications for broader industrial applications, including the development of standardized sensor-contamination evaluation methods, enhancement of LiDAR manufacturing quality control, and potential integration into automated surface treatment or particulate deposition processes in other precision engineering fields. Future research will apply the optimal dust-spraying method developed in this study to scenario-based vehicle testing to enable the evaluation of autonomous driving safety under dust-induced sensor contamination and validate the reproducibility of contamination techniques. Nevertheless, further studies are required to establish standard dust filters by applying a broader range of dust types and concentrations to the LiDAR plate, enabling performance evaluation across diverse LiDAR systems. Additionally, because the current flat plate may not be applicable to circular or curved LiDAR geometries, the development of contamination plates incorporating surface curvature should be explored.