## 3 Materials and Methods
### Production Flow and Sensor Placement  
The production process begins with the tube production machine, where laminate strips are transformed into semi-finished tubes. This stage includes cutting, high-frequency welding, and coating the tubes with a plastic layer. These tubes then pass through a calibration and cooling phase. Sensors S1 (optical counter), S2 (diameter gauge), and S3 (eddy current sensor for aluminum layer integrity) are placed at this stage to monitor tube formation and detect anomalies in size or structure.  
After this, the tubes move to the head and capping unit, where tube heads are formed using molten plastic and caps are attached. Sensors S4 (vision system) and S5 (torque sensor) track cap alignment and sealing quality. The subsequent stage is printing and varnishing, where designs are applied using UV-dried inks, and a varnish layer is added for protection. Sensors S6 through S8 (vision systems for color registration and defect detection) ensure that the final appearance satisfies quality standards. Energy consumption for each major unit (Extruder, Header, Capper, Printing) is monitored by dedicated power meters integrated into the MES. The final step involves packaging, where the tubes are automatically sorted, oriented, and placed in cartons or pallets according to customer specifications. While confidentiality agreements prevent the publication of equipment photographs, Figures 3 and 4 provide schematic diagrams of representative production lines.  
The Life Cycle Assessment (LCA) for this facility is summarized in Figure 5. It evaluates the environmental and operational impacts of the production process, from the sourcing of raw materials to the final product. The process begins with materials like Polyfoil(r) (a combination of plastic and aluminum for barrier properties), polyethylene (PE) for flexible tubes, and coextruded materials for durability. These materials ensure quality and suitability for a variety of applications.  
Energy consumption is a major component, and electricity drives key operations like extrusion, welding, and UV printing. Renewable energy, such as solar panels, reduces the dependency on fossil fuels. Water is mainly used for cooling in extrusion and calibration processes, and centralized treatment plants have significantly reduced overall water usage.  
The manufacturing process includes tube production (laminate handling, welding, extrusion), quality control (calibration and inspection), heading and capping (attaching tube heads and caps), printing and varnishing (for aesthetics and durability), and packaging (organizing and boxing). Each stage ensures precision and efficiency in production.  
Waste management focuses on recycling, with 85% of production waste being reused and 15% thermally recovered. Packaging waste is minimized by using materials with a high recycled content. Environmental impacts, including CO\({}_{2}\) emissions, have been reduced through energy-efficient systems like pellet heating, and low-solvent paints are used to improve resource efficiency.  
Figure 4: Schematic of production line TL203 (80–105 tubes per min).  
Figure 3: Schematic of production line TL201 (68 tubes per min).