Theoretical and Experimental Investigation into Generation of Wrinkling and Slip in Plastic-Films under Transportation

Abstract

In the transport processes of plastic-films, wrinkling is sometimes generated due to misalignment of roller. To avoid the wrinkling, it is effective to reduce the web tension. However, under the low web tension, the traction inevitably falls as transport velocity increases due to air entrainment and is accompanied by the onset of slip. This paper examined such a trade-off relation between the wrinkling generation due to roller misalignment and onset of slip. At first, the prediction models for slippage and wrinkling are formulated based on the contact mechanics. Moreover, the observation method of wrinkling generation and slip was presented and the critical misalignment angle, critical web tension to generate wrinkling and slip onset velocity were measured for various operation conditions. Five types of PET (polyethylene terephthalate) films were used for measurements. From the experimental and theoretical results, the effects of roller velocity, anisotropic Young's modulii and film thickness on the relation between the roller misalignment and web tension were made clear. As a summary of experimental and theoretical works, the stable transportation map was newly introduced for protecting both wrinkling and slip.