Toward a Digital Twin: Extrusion Die for Manufacturing Polyphenylene Sulfide Solar Thermal Collectors

ABSTRACT The European Union's commitment to increasing renewable energy use emphasizes the relevance of solar thermal collectors. A key component in flat‐plate solar collectors is the absorber plate. Compared to traditional metal‐based solar collectors, polyphenylene sulfide (PPS) offers several advantages including lower weight, easier installation, and strong thermal and corrosion resistance. However, extrusion of defect‐free PPS plates is challenging. Accurate control of die exit temperatures and process conditions is crucial for producing high‐quality PPS absorber plates, as even small deviations can cause slag deposition at the die exit. Detached slag deposits can lead to serious surface defects and costly production interruptions. A digital representation of the die allows estimation of how process‐related factors affect PPS at the die exit. In this study, a detailed 3D model predicts temperatures that closely align with thermocouple data from a specific production run, revealing that measured die temperatures are about 10°C lower than the PPS die exit temperature. Melt inlet temperature and heater settings are shown to have significant impact on the die exit temperatures, while the effect of the ambient temperature is small. A non‐intrusive POD‐based reduced‐order model enables real‐time prediction of the die exit temperature, combining CFD data, interpolation, and sensor integration to support quality control and waste reduction in the extrusion process.