ETD

• Industrial Diagnostics
• Paper Production
• Process Optimization
• Tissue Machine

This thesis originates from the candidate’s internship at Toscotec S.p.A., an Italian company of international standing in the design and manufacture of advanced tissue production lines. The research addresses two major operational challenges encountered during the start-up and optimization phases of tissue machines: the influence of headbox lip geometry and pressure distribution on sheet formation, and the emergence of chatter marks on the Yankee dryer surface.
A comprehensive methodology combining field inspections, diagnostic analyses, and simulation tools has been developed within the framework of Root Cause Analysis (RCA) to identify and mitigate both mechanical and thermal deviations. The results demonstrate that millimetric inaccuracies in headbox calibration critically affect cross-direction basis-weight uniformity, while chatter phenomena are predominantly linked to subtle thermal imbalances, along with disturbances in surface roughness and coating behaviour, and were not always attributable just to the cases of mechanical misalignment in the creping system.
Corrective actions—such as headbox lip realignment, micrometer recalibration, and Soda Straw optimization—proved effective in restoring process stability and confirmed the high sensitivity of modern tissue machines to geometric precision and thermal equilibrium.
Methodologically, the thesis underscores the importance of integrating theoretical modelling, OEM standards, and observation-based procedures within a coherent and traceable analytical framework. This integration ensured reliable, reproducible results, bridging scientific knowledge with industrial application. Furthermore, preventive maintenance and continuous trend monitoring emerged as strategic practices that enhance product quality and equipment integrity while generating measurable economic savings.
In a broader perspective, the study highlights that sustainable advancement in the tissue industry depends on the symmetry between mechanical precision, digital process governance, and environmental responsibility. The proposed directions for future development—automation of headbox calibration, digital-twin implementation, and energy-efficiency optimization—delineate a forward-looking framework for resource efficient and environmentally sustainable production, where technological innovation converges with ecological accountability and responsible corporate management.