Multilayer Roll-to-Roll Screen-Printing for Printed Electronics Applications

Multilayer roll-to-roll (R2R) printing of functional ink, e.g. electrically conductive carbon ink, is challenging on a polymer substrate such as polyethylene terephthalate (PET) films. Hence the objective of this study is to investigate the reinsertion multilayer R2R screen printing process of functional ink for functional printing applications. The roll-to-roll screen printing machine used in this study can process substrate up to 1000mm width. The R2R screen has a repeat length of 400mm and effective printing width of 990mm. The mesh plate used is 275 lines-per-inch mesh with 39μm opening, 53μm non-opening, and 83μm thick. The multilayer printing study was conducted by aligning two dimensions (9×9mm and 10×10mm) of square-array patterns. In this study, the inaccuracy of the web tension was found to be influenced mainly by the nip roller configuration. The nip roller configuration was improved by allowing them to be placed relatively closer to the printing unit and the results indicated that the web tension variation was reduces to below 10%. Effects of the web tension variation on the registration errors were also discussed. At the least web tension variation (±6%), the average registration errors at MD and CD are respectively below 500μm and below 100μm. An interactive printed lighting (860×390 mm size) which is required to be printed with an alignment error of less than 100 μm was also demonstrated and discussed.