Optimizing Roller Design to Improve Web Strain Uniformity in Roll-to-Roll Process

Abstract

In this work, we investigated the compensation of strain deviation in the machine direction of a web in the roll-to-roll process. As flexible devices have become popular, many researchers have begun to study roll-to-roll processes for the mass-production of flexible devices at low cost. In the continuous roll-to-roll process, an electronic circuit pattern is printed on the web while the web is transferring. Due to tension and Poisson’s ratio, a non-uniform strain distribution can occur in the web. This strain distribution occurs mainly at the center of the web and causes a register error in the machine direction. In this work, we designed a roller to minimize the strain deviation. The design of the compensation roller was optimized using the design of experiments (DOE) methodology and analysis of variance (ANOVA), and the compensation performance was verified through experiments and simulations. According to the results of a comparative experiment conducted to confirm the correcting performance of the optimized roller, the strain deviation in the machine direction decreased by approximately 48% with the proposed roller compared to that of the conventional roller.

Web Unevenness Due to Thermal Deformation in the Roll-to-Roll Manufacturing Process

“…The temperature distribution of the web in the FEM was set considering the temperature distribution at this position. Considering the tension distribution shown in Figure 1c, boundary conditions at both edges were defined, and set tension was applied to both sides of the web [21]. The drying temperature range was set from 30 to 120 • C considering the temperature range of the actual dryer in the R2R process.…”

Web Wrinkle Defects due to Temperature Profile in Roll-to-Roll Manufacturing Systems

“…The web with lateral displacement partially slips where it contacts a roller, and therefore part of the web is deformed in the z-direction (ZD). If rollers are not aligned in parallel on the same plane (roller misalignment) during the roll-to-roll web handling process, strain deviation occurs in the web, which leads to lateral displacement and web wrinkles [ 36 , 37 ].…”