Statistical control and experimental design for edge bead reduction in laminating process

Abstract

Edge bead formation is a well-known phenomenon typically happening in the lamination due to the physics of this process. It causes the defect of high edge observed in the carton roll after the laminated carton sheets are wrapped around the roller in Company X; the affected carton sheets can no longer be fed into customers' filling machines due to the uneven surface. To address this problem, a model with process parameters and quality characteristics was built to define the lamination. Based on this model, the capability of measurement system was verified and current process capability was calculated. After that, Shewhart control charts were employed to identify the assignable causes and to bring the process to in-control state. Then, a designed experiment was conducted to find the optimal operating conditions. It was found that line speed, screw speed, die-bolt power and die-lip build-up are most likely to be subject to disturbances. In addition, diebolt power, manifold plug and deckle blade have a statistically significant impact on the edge bead formation. As a result, an out-of-control-action plan was proposed and a recipe is recommended for edge bead reduction in laminating process.