## 4 Results and Discussion
### The Concept of Changes in the Production Process--Analysis and Evaluation  
The cavity cutting station of the analyzed semi-finished product was identified as a bottleneck of the analyzed line. The residence time of the semi-finished product in this section slowed down the entire system and reduced the production capacity. Due to the large area of the production hall, it was possible to introduce a second nest-cutting station into the system. The concept of the changes assumed the purchase of a second Fanuc robot and the involvement of an additional employee.  
To assess whether the presented solution would improve the process and to what extent the individual parameters of the system would change, it was decided to use the FlexSim software and modify the original model of the system. The following changes were made to the base model:  
* A station for cutting out recess No. 2 with the same processing time as station No. 1 was added,
* A second operator of the cutting machine was introduced,
* The logic of selecting the position for the excision of the cavity due to availability was established,
* A queue in front of the foot welding station was added.  
After making these changes, the model shown in Figure 13 was obtained.  
The next step was to simulate the modified system. As with the original model, the duration of the experiment was set at 365 days. Figure 14 shows the daily production of products, Figure 15 shows the graphs showing the use of machines in the analyzed production line and Figure 16 shows the sheet metal composition in the new conceptual model.  
Figure 13: Design of a new model production line with an additional station. Source: own study.  
Figure 16: The state of the sheet metal composition in the conceptual model. Source: own study.  
Figure 14: Daily production of products in the concept model. Source: own study.  
Figure 15: The use of individual sections—machines in the conceptual model—percentage share. Source: own study.  
After analyzing the data from the conceptual model, it was found that:  
* The maximum daily production of the final product increased to about 90 pieces,
* An increase in the phenomenon of inactivity was observed in the selected sections, which resulted from the faster execution of accepted orders,
* The introduction of a second cavity-cutting station eliminated the bottleneck phenomenon at this stage,
* In the remaining sections, it was found that the machines were used to the same extent, but the blocking time of these devices was shortened,
* The stock level of sheet metal was more likely to reach a coefficient of 0.  
Based on observations of both the original production line and the conceptual one, it was found that the introduction of an additional welding station resulted in an increase in production efficiency compared to the original model of the production line. A noticeable result of these changes was an increase in production from about 80-90 units. In addition, it was noticed that the condition of the machines preceding the stand had changed. In the case of welding, the percentage of time during which equipment was blocked and waiting for the possibility of transferring the semi-finished product to the next stages of the production process was significantly reduced.