Simulation-based optimisation for the side seam heating nozzles in the paper cup manufacturing system

Abstract

This thesis investigates the influence of hot-air nozzle geometry on the paper cup side seam heating stage during the manufacturing process, this is a critical step which shapes the seal quality, energy efficiency and the overall production consistency. Although the sealing period is brief, it requires carefully controlled heating to properly activate the polymer coating on the paperboard. Four nozzle configurations were modelled in Autodesk Fusion 360 and evaluated using Computational Fluid Dynamics simulations in Ansys Fluent. The baseline model which is based on the NEW TOP-138S paper cup manufacturing machine at LUT packaging laboratory, showed strong but non-uniform heating, creating distinct hot spots under the impinging jets and cooler regions between the jets. Three modified configurations, a slotted outlet, a multi-row arrangement with smaller jets, and an enlarged-outlet variant, were modelled to explore alternative effects. Among these, the multi-row small-outlet design produced the most uniform and efficient heat distribution, achieving higher average temperatures with minimal variation across the side seam. The findings highlight how relatively small geometric changes can improve both thermal performance and sealing reliability, and they offer a clear direction for future optimisation of industrial cup-forming equipment.