Strain Optimization of Tensioned Web through Computational Fluid Dynamics in the Roll-to-Roll Drying Process

Abstract

Unpredictable web temperature distributions in the dryer and strain deviations in the cross-machine (CMD) and machine (MD) directions could hamper the manufacture of smooth functional layers on polymer-based webs through the roll-to-roll (R2R) continuous process system. However, research on this topic is limited. In this study, we developed a structural analysis model using the temperature distribution of the web as a boundary condition to analyze the drying mechanism of the dryer used in an R2R system. Based on the results of this model, we then applied structural modifications to the flow channel and hole density of the aluminum plate of the dryer. The model successfully predicted the temperature and strain distributions of the web inside the dryer in the CMD and MD by forming a tension according to the speed difference of the driven rolls at both ends of the span. Our structural improvements significantly reduced the temperature deviation of the moving web inside the dryer by up to 74% and decreased the strain deviation by up to 46%. The findings can help prevent web unevenness during the drying process of the R2R system, which is essential to minimize the formation of defects on functional layers built over polymer-based webs.

Rapid Uniformity Analysis of Fully Printed SWCNT-Based Thin Film Transistor Arrays via Roll-to-Roll Gravure Process

“…This control system allowed us to achieve a printing registration accuracy of ±25 µm in the machining direction (MD) and ±50 µm in the transverse direction (TD). Additionally, our R2R-printing unit was designed to actively compensate for the expansion of PET film as it passed through the 150 °C of drying chamber [ 17 ]. The gate, dielectric, and drain-source layers were continuously printed by employing two printing units with a web width of 250 mm and the same printing speed of 90 mm/s.…”

Image Data-Centric Visual Feature Selection on Roll-to-Roll Slot-Die Coating Systems for Edge Wave Coating Defect Detection

“…In an R2R setup, materials are continuously fed into the system as rolls, enabling rapid production as the manufacturing process occurs on the moving material web [ 7 , 8 , 9 ]. A key process of R2R manufacturing is the coating process, where a thin layer of material is applied to a substrate surface to impart specific functionalities or properties [ 10 , 11 ]. As coating quality significantly influences the deposition of conductive materials, insulating materials, functional layers, consistent monitoring, and maintenance of the process are required [ 12 ].…”

Structural Optimization of Scarfing Machine with Acceleration Profile and Multi-Objective Genetic Algorithm Approach

“…When conducting mechanical scarfing, the scarfing unit is mounted on a frame, and stability is ensured as the operation occurs at high temperatures. However, during the manufacture of frame equipment, excessive focus on stability can lead to the use of unnecessary materials and components, which can incur additional costs [16][17][18]. When restarting scarfing equipment after a stop, different shocks are applied to the structure depending on the acceleration profile [19][20][21].…”