Utilization of Thermal Imaging in the Evaluation of Ultrasonic Sealing of Packaging Materials

Ultrasonic sealing is a method used in packaging to create tight closures and seals using various packaging materials. One advantage of ultrasonic sealing over conventional heat sealing process is the fast and localized heat generation, which can be beneficial for many food packaging applications. Optimization of the ultrasonic process has been studied previously but thermal imaging of the sealing process is yet to be used for optimization. The distribution and behavior of heat in the sealing area is an important factor for seal quality, and there is still a need to better understand the sealing phenomena in ultrasonic sealing with different materials. In this paper, the suitability of thermal imaging for online (real-time) and offline analysis of the ultrasonic sealing of various packaging materials will be investigated. The aim is to find out how the sealing process can be analyzed and how the information from the thermal imaging can be related to the seal quality. The results show clear correlation between seal quality and thermal distribution of the seal during sealing. Possible benefits of using ultrasonic sealing over hot bar sealing can also be seen. These results could be used to increase the production speed and efficiency by optimizing the sealing parameters, and to improve the quality of the sealed packages and to develop a quality inspection tool for packaging manufacturers.