Ultrasonic monitoring of the seal quality in flexible food packages

Ultrasonic Backscattered Amplitude Integral (BAI) values are used to detect critical and major defects such as nonbonding, wrinkles and bubbles distri buted within the seal area of flexible food packages. The BAI-mode imaging by itself is not capable of detecting such nonbonding, wrinkles and bubbles distributed within Me seal area, For this study, model defects in the seal region of all-plastic and foil-containing films were created by varying Me sealing-bar temperature. Seal regions were scanned by a 17.3-MHz ultrasoni c transducer, and the waveform for each scan point was processed by the BAI -mode method. The mean and the coefficient of variation of the BAI values ( BAICV) were calculated. It is shown that a combination of mean BAI value an d BAICV value can detect defects distributed in seals in flexible food pack ages. This technique has the potential of providing a real-time, on-line co ntrol by sensing whether a proper seal has been achieved.