Simulation and optimization of non-Newtonian ink transfer of offset printing process

This study introduces a novel approach to investigating and optimizing the ink transfer process in offset printing. Using OpenFOAM software, the ink, modeled as a non-Newtonian fluid via the Carreau model, is analyzed through simulations of the volume of fluid method. The study explores the unique influence of geometric and physical parameters—such as contact angles, Reynolds number (Re), and capillary number (Ca)—on key ink transfer metrics: break time (BT) and ink transfer ratio (TR). Unlike previous works, this research establishes predictive analytical relationships for BT and TR using the design of experiments method, providing a deeper understanding of the complex interactions in ink transfer. Furthermore, the process optimization through response surface methodology represents a novel application in this domain, offering actionable insights to enhance printing performance. The results indicate that increasing the top plate contact angle from 15° to 75° reduces TR by 44%, showcasing the critical impact of contact angles. The resulting equations accurately predict the effects of key quantities, bridging the gap between modeling and optimization and establishing a new benchmark for enhancing ink transfer efficiency.