## 5 Conclusions  
Observations of production environments indicate that many companies are currently implementing the idea of Industry 4.0 [63]. This process builds the belief that the implementation of related solutions will allow for significant efficiency improvements, cost reductions, optimization and the harmonization of production processes on the way to sustainable development. One of the key solutions to achieve this success seems to be the use of simulation modelling and the use of specialized tools such as FlexSim to diagnose the entire production system or its selected components [64]. There is no doubt that simulation modelling enables the optimization of product flow and, consequently, the full use of available resources. This effect is possible by conducting simulation experiments on the production line without the need to stop production [54]. The case of using a simulation on the example of the selected good analyzed in this article certainly confirmed how complicated modern production processes can be. In a way, it indicates how many factors affect the difficulties in proper production planning and how important it is to reduce unnecessary activities to optimize production. Based on the presented research, the following conclusions were formulated:  
1. Simulation models can be used to identify adverse phenomena occurring in the area of production processes. They reflect the functioning of systems in a production environment, which are subjected to all kinds of analyses. With their help, it is possible to test the validity of the proposed conceptual and model solutions without the need to make actual changes to the production system and without incurring significant financial outlays. 2. Tools such as FlexSim contain extensive libraries of 3D objects. This makes it possible to faithfully reproduce the analyzed process--the production line. This allows for the construction of detailed models of production systems, the conducting of experiments and the analysis of the achieved results. It is important to emphasize that advanced algorithms together with statistical tools enable the mapping of the natural variability of the process. Thanks to these tools, it is also possible to analyze a large number of alternative scenarios to find a solution, thus confirming the validity of strategic decisions, finding the optimal solution from hundreds of possibilities or even creating the best production plan. In addition, these programs have the function of integration with other tools (e.g., Microsoft 365 Excel 2016 or 2024 Autodesk Inc. CAD--Computer-Aided Design--software). 3. The use of the FlexSim software made it possible to propose solutions that could bring positive effects to the existing production line without incurring additional costs. Furthermore, the tool used significantly reduced the time spent on research and development. The simulation of the system allowed for the 365-day life cycle of the modified line to be analyzed in one day, which is an extremely short time compared to the period during which the data were obtained. 4. According to the authors, the FlexSim modelling and simulation tool can also be used to create new production lines. At the same time, it provides a solid foundation supporting the digital transformation of Industry 4.0. This software allows for the analysis of project costs and potential profits from production. This makes it possible to decide whether to start or reject a project of building a production line without incurring additional costs. Thus, the authors postulate that in the era of growing interest in the idea of Industry 4.0, it is worth considering investing in simulation software, especially in the case of corporations that can use it in many areas and branches of a given group. Furthermore, simulation software can not only improve individual internal processes but also harmonize the coordination of the entire supply chain. The benefits of simulation will then also be noticeable in other links in the production chain.