The analysis of high-speed printing machine using fluid-structure interaction method

Tight contact between a roller and web is required to achieve a harmonious operation of a web handling process line. Nip force is applied to help and maintain this close contact, but proper amount of entrained air and nip force should be also considered to minimize ballooning phenomenon. In this paper, various web materials, PET(Polyester) and OPP(Oriented Poly Propylene) have been selected and investigated to satisfy high-speed printing requirement. Several web speeds, web tensions, and temperature conditions are imposed on each web materials and the pressure and gap profile as well as nip force have been calculated. Increase of both the winding roller radius and the incoming wrap angle are considered under proper taper tension at 500 m/min of rewinding roller. By solving coupled Reynolds equation and web deflection equation simultaneously, the fluid-structure interaction process has been developed and is applied to the rewinding roller to investigate the ballooning phenomenon which causes guiding problems in high-speed printing performance conditions. In this study, it is found that the amount of entrained air is proportional to the increase of web speed at a fixed tension and is inversely proportional to the increase of tension at a fixed web speed, while nip force becomes bigger as web speed increases at a fixed tension but its change is small and also increases rapidly with the increase of tension at a fixed web speed. By adjusting the linear taper tension, stress distribution between rewinding webs can be remarkably reduced and stable pressure and gap profile with ignorable ballooning phenomenon have been found.