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Talking about medical devices, ensuring seal quality or seal strength of sterile medical device packaging are extremely crucial as well as highly regulated. Medical device package seal contains a flexible barrier which is joined to the rigid container through an advanced adhesive. A defect in the seal such as an incomplete or weak seal can initiate leaks, contaminating the product and reducing its shelf life. Hence, for quality control purposes, seal quality inspection of medical device packages is mandatory.

Historically, manual inspection was the most popular method used to inspect seal defects. Although this is covered by an ASTM method (ASTM F1886), it lacked accuracy and reliability in terms of test results. “There is a huge shift in the industry towards deterministic and quantitative test methods,” comments Oliver Stauffer, Chief Executive Officer at PTI - Packaging Technologies & Inspection. “This includes Vacuum Decay and Airborne Ultrasound for medical device applications. The industry is currently moving away from dye ingress and manual visual inspection because there are so many blind spots in applying them and there’s a huge false sense of assurance.”

Airborne Ultrasound technology is a non-destructive seal integrity test method capable of advanced seal quality inspection of pouches and flexible packaging. Seal defects can be of two types- leak defects and non- leak defects. While it is easier to detect a leak defect, detecting non-leak defects can be a challenge for manufacturers. However, Airborne Ultrasound technology allows non-destructive Container Closure Integrity testing of multiple seal defects including visible and invisible, leaking and non-leaking, process-related and random- making it a practical solution for medical device seal quality inspection.

Technology overview

Airborne Ultrasound technology utilizes ultrasound waves to detect defects in package seals. Ultrasound waves are passed through the material as the package seal moves along the sensor head. This causes reflections of sound waves. In the presence of a leak, the signal strength is either eliminated or reduced. Such variations in signal strength are analyzed to identify the defects. Seal scan testing is a practical solution to recognize defects, such as inconsistent seals or areas of seals that fail to meet minimum width requirement. Seal-Scan® and Seal-Sensor utilize non-contact airborne ultrasonic testing technology for advanced seal quality inspection. Seal-Scan® technology has been proven in the field by several online and offline units installed.

Benefits of Airborne Ultrasound technology

• Deterministic seal quality inspection method that produces quantitative results.
• This method works for any material type and combinations regardless of color, transparency, print, surface finish or porosity.  
• Non-destructive and non-subjective test method that requires no sample preparation.
• Technology can be integrated for 100% online defect detection of the final pouch seal.
• Repeatable, reproducible and reliable results for seal quality inspection.
• Cost-effective solution for seal integrity testing and seal analysis that characterizes overall quality and uniformity of the seal.