ASTM F 3004-13: Using Ultrasound for Checking Package Seal Quality
ASTM has released a new test method, F3004-13 Standard Test Method for Evaluation of Seal Quality and Integrity Using Airborne Ultrasound. This is a non-destructive method for package seal testing. The detection technique is similar to that used in the aircraft industry to ensure that there are no defects in welds created during airframe construction; however, for package testing, liquid is not used as a sound carrier.
I first became interested in this new technology for checking the seals of sterile barrier packaging some years ago. When the system was being promoted in Ireland by Alpha Vision Design, I featured the new technology in an article for European Medical Device Technology. Samples reviewed at that time demonstrated that, by firing airborne ultrasound through the seal area under inspection, a sensitive non-contact receiver could detect and interpret the transmitted ultrasound signal enabling creation of a coloured "opto-acoustic" display that would reveal any significant seal defects. Use of this system provides the ability to assess seal quality without the need for destructive package opening.
The actual developers are pti Packaging Systems, which offers a range of non-destructive inspection systems for testing seal and packaging integrity. Pti's current advertising proudly shows how pleased they are that their Seal-Scan® technology has been given the "seal of approval" by being the subject of ASTM test method F3004-13.
Oliver Stauffer, Chief Operating Officer at Packaging Technologies and Inspection, can be heard extolling the virtues of this non-contact testing method in a video recorded at PACK EXPO 2013. The video is available at HealthCarePackaging.com.
In his video, Stauffer enthusiastically tells us that the system can detect defects "down to about 150 microns." He may be over optimistic; I draw your attention to results of an inter-laboratory study, conducted in 2012 for ASTM, which examined the precision of this test method.
ASTM F3004-13 "Table 8 Summary of All Readings" is shown below. This shows that the smallest channel detected, almost 100 percent of the time, was 1mm.
This is not intended to detract from the capability of an excellent tool for detecting sealing problems. It does mean that for any specific use, the packager must, when validating this detection method, be sure to identify its sensitivity and reliability for this specific packaging material combination and line speed. I look forward to seeing the Seal-Scan® system in use on a packaging line.
Rolande Hall, FIMMM Pkg Prof