Sealing is one of the most important steps in packaging processes, since the sealed seam is the most sensitive zone of a package in terms of quality. For this reason, a major focus in flexible packaging is the sealing process, and among this heat sealing is the most frequently used technology. In detail, applications of heat sealing processes are confronted with four conflicting objectives: Increasing seam quality, reducing dwell time, reducing sealing temperature and increasing process robustness towards varying conditions. Typical problems, such as identification of the optimum process parameters or selection of the most appropriate packaging film, are subject to these conflicting objectives.
This conference paper presents a recently published, experimental characterization approach for heat sealing processes based on a multi-objective optimization algorithm. The approach provides easy-to-read charts showing all optimum sealing parameters with regard to the four essential objectives of heat sealing: seam quality, dwell time, sealing temperature and process robustness. This paper applies the new approach to the problem of comparing different packaging films and selecting the most appropriate one for a specific case. For this purpose, the characterization approach is extended to an optimality-based comparison approach using a multi-objective concept selection method. The extended approach provides easy-to-read charts showing which packaging film is most qualified for a specific use case. Three case studies illustrate the new approach: 1) Analyzing transport damages of beverages powder packages. 2) Identifying and comparing optimum sealing parameter of a standard, mono-material and fiber based packaging film regarding tightness and visual properties of the produced sachets. 3) Analyzing the effect of additional aluminum layers on sealing characteristics regarding hot-tack. The conference paper concludes with an outlook on future applications of the approach regarding processing and converting of polymer films such as film extrusion.