How does one troubleshoot a package sealing process to ensure that the seals are free of channels?
Package sealing processes are a critical element of any flexible packaging design and implementation project. Whether one is creating a 2D flat pouch, a flow-wrap package, a tray/lid combination, or a 3D form-fill-seal package, care must be taken to design a sealing process that is both robust and repeatable, and that produces defect-free packaging on a consistent basis. One key element of that design process is the material supplier, who will be able to recommend sealing parameters based on the material and the sealing equipment, but who will also be able to provide expertise and assistance in troubleshooting efforts should the need arise.
Besides the material supplier, another helpful resource is a document issued by ASTM International that can assist converters and OEM’s in designing and troubleshooting sealing processes. F1886/F1886M-09, Standard Test Method for Determining Integrity of Seals for Flexible Packaging by Visual Inspection, which is under the jurisdiction of ASTM Committee F02 (Flexible Barrier Materials), provides a method for visually inspecting package seals for channel defects down to 75 mm. This document also includes Appendix X1, Visual seal appearance characteristics and probable causes. In this helpful appendix, the user will find helpful information on inspecting seals for under-sealed, unsealed, and over-sealed areas, narrow seals, channels, wrinkles, fold-overs, and cracks, and tears and pinholes. For each of these seal characteristics, guidance is provided on probable causes and potential solutions.
Another helpful resource is F2097-14, Standard Guide for Design and Evaluation of Primary Flexible Packaging for Medical Products. This guide provides directions for the design and evaluation of primary flexible packages for medical products, and specifically serves as a compendium of relevant test methods, practices, and procedures.