Recently, there has been increasing demand for flexible electronic applications such as flexible displays, foldable smartphones, and flexible batteries based on flexible substrates. The roll-to-roll additive process has attracted tremendous attention regarding manufacturing such flexible electric devices because of its characteristics of eco-friendliness, large area of compatibility, and high flexibility, in contrast to traditional lithography or vaper evaporation methods. The mass production of roll-to-roll process tension control in precision is the most crucial assignment to be achieved. For the tension control, the load cell and dancer systems are used to regulate tension disturbance. A pendulum dancer system was extensively applied for unwinder or rewinder whose span length varied in the roll-to-roll printing and coating process. However, there have been an inadequate number of studies regarding tension control using the dancer system for mass production. In this paper, we propose a mathematical model of center pivot rotary dancer system revolving dual idle rolls around the pivot. Parametric studies are conducted as a function of inertia, span length, width of substrate, and operation velocity. Additionally, an impulse response was conducted for the time domain analysis. These results can be used for the mass production of roll-to-roll additive process.

This study proposes a method for identifying correlations between tension and drop height for sessile droplets in a roll-toroll processing system. The effect of tension and drop height on the contact angle of a sessile droplet is presented. Design of experiment (DOE) methodology and statistical analysis are used to define a correlation between the process parameters. The contact angle is decreased while increasing tension and drop height. The influence of the tension is less significant on the contact angle compared with the effect of the drop height. However, tension should be considered as a major parameter because it is not easy to fix with roll eccentricity and compensating speed of the driven roll. The results of this study show that the effect of tension on the contact angle of a sessile droplet is more important than drop height because the drop height is fixed when the process systems are determined.