Multicriteria evaluation and optimization of the ultrasonic sealing performance based on design of experiments and response surface methodology

Abstract

Proper closure is an essential packaging quality aspect and can, amongst others, be achieved with ultrasonic sealing. The ultrasonic sealing performance depends on the film type, and the seal settings, such as seal time, applied force and ultrasonic amplitude. Because these parameters are less intuitive than heat seal parameters and optimal settings are undefined for many films, this work presents an efficient approach to evaluate the effect of these settings on the ultrasonic sealing performance. An experimental design defines the experiments to perform. A response surface methodology is then used to model the relation between seal settings and sealing performance. Based on these models, the seal settings are optimized. As there are several criteria to express sealing performance, single-criteria and multicriteria optimizations are described.The approach was illustrated for a polyethylene terephthalate/linear low-density polyethylene-C4 film. The seal settings were optimized to obtain high seal strength, limited ultrasonic horn displacement, and low seal energy. The optimum settings were 0.1 seconds (seal time), 4.32 N/mm (force), and 28.75 μm (amplitude). The predicted optimum strength, horn displacement, and energy were 2.32 N/mm, 40 μm, and 11.66 J, respectively. Besides the optimum, the seal window is also of interest. A broad seal window ensures sufficient seal strength for a wide range of settings. For the polyethylene terephthalate/linear low-density polyethylene-C4 film, a strength of ≥90% of the optimum was obtained for 39% of the input combinations within the design space.The presented approach is widely applicable (other films and sealing processes) since it is flexible in the input parameters, design, and responses. KEYWORDSdesign of experiments, multicriteria seal optimization, polyolefin packaging, response surface methodology, ultrasonic sealing

Evaluation and optimization of seal behaviour through solid contamination of heat‐sealed films

“…Secondly, an experimental design is set up. In this study, a 20‐point I‐optimal design was selected, rather than the Box‐Behnken design of a previous study . This I‐optimal design allows to include corner points of the design space, which represent extreme parameter combinations.…”

“…The criteria of this selection are R 2 , Akaike information criterion (AIC), and Bayesian information criterion (BIC). For a more detailed description of the model selection, the reader is referred to the previous study on ultrasonic seals …”

“…The success of the confirmation is assessed by following an approach based on a confidence interval calculation of the confirmation runs (CICon approach) as suggested in previous research . For details, the reader is referred to the previous study on ultrasonic seals …”

“…Firstly, a protocol to apply solid contamination in a standardized way is described, this protocol was missing in previous studies with powder or granulate contamination. Secondly, an optimization method is presented that is based on a previous study on ultrasonic sealing . In this study, a similar methodology is used in order to receive information on the influence of all relevant seal parameters on the heat conductive sealing process based on a limited number of carefully selected experiments.…”

Evaluation and optimization of the peel performance of a heat sealed topfilm and bottomweb undergoing cool processing

“…This method is based on previous studies with a similar methodology to optimize seal strength with a limited amount of tests. 6,7 A second objective is to evaluate the relation between peel performance and cool processing by applying the proposed method on a commercial packaging concept with polyethylene (=PE) seal layer.…”