## 3 Results
### Contact Angle  
Figure 3 presents the average contact angle values as a function of the Ra parameter. However, no unambiguous correlations between the change in contact angle and the recorded roughness index were found in the studies. The mechanisms of interaction between selected technological parameters do not enable us to determine the reasons for such discrepancies unambiguously. The coating formed from one putty layer at the assumed process parameters is characterized by the highest roughness. In this case, the hydrophobic character of the surface was weakened, which ensured good adhesion properties for the subsequent layers. Further layer application resulted in a decrease in wettability, which contributed to increased contact angle. Although final coatings exhibited a similar roughness to the system with one layer of putty, the contact angle was not reduced. In addition, it was observed that the systems prepared at varying conveyor speeds showed slight differences in the formation of the recorded values. These differences are due to the doses of energy distributed as a result of the longer residence of the samples under the radiator. Different levels for different speeds were also recorded between primer systems. The smallest impact of speed was observed in the case of topcoat systems. This is undoubtedly related to the type of products and their composition. In general, systems with undercoats only had lower values than final coatings with topcoats. From the point of view of the technological process, this is very advantageous. The contact area between the liquid and the substrate is then greater. Therefore, it can be indirectly concluded that the varnish products will have the ability to wet the substrate and achieve a favorable adhesive bond between the wetted material and the varnish coatings [43; 44]. On the other hand, the recorded higher contact angle contributes to the formation of hydrophobic properties of the topcoats, which is desirable during the use of the final products. When considering the  
Figure 3: Formation of contact angle for the tested systems. evaluated parameter as a function of the number of coatings applied, the lowest values were found for one putty coating at the maximum lamp setting regardless of the conveyor speed. An increase in this parameter was recorded with the application of subsequent layers. This is due to an increase in the homogeneity of the varnish coating and the deliberate action of changing the energy density supplied during the refinement process. Coatings that are less cross-linked are more wettable and, at the same time, more susceptible to sanding. The sanding process is an advisable treatment after the application of putty layers. With regard to the systems considered, the highest angle value was achieved by system 1-15a consisting of five coatings comprising two layers of putty and primer using the OPTI and one layer of topcoating 6 g/m\({}^{2}\) at the maximum settings of the electromagnetic beam focusing lamps and for each LED module (Table 6). The observed differences for each system are the result of different energy doses of absorbed electromagnetic radiation. In addition, it was noted that the use of higher conveyor speeds contributes to lower values of the contact angle, which is undoubtedly related to the absorption of different energy doses (Figure 4). A correlation analysis based on [PERSON]'s criterion multiple comparisons of means with a 95% confidence level shows that the energy density applied to the surface has an influence on the formation of the contact angle. In many cases, for the same type of applied materials, no effects of changing the application amount on the contact angle were observed. The small impact of the amount of liquid materials applied on the surface with the same energy density was observed between the topcoat, samples 1-14d (12 g/m\({}^{2}\)), and 1-15d (6 g/m\({}^{2}\)).