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For sterile medical devices, seal integrity testing ensures product efficacy, shelf-life stability, and microbial sterility. Common defects that can threaten the integrity of the seal include voids, wrinkles, dust or other random particles. Hence, inspecting seals after they have been formed is important. Earlier, visual inspection or other destructive testing methods were used for seal quality inspection. However, they lacked accuracy and reliability in test results. But technology is changing. Today, the market offers a range of non-destructive inspection techniques that ensure highly sensitive and reliable seal quality inspection. Even then, the suitability depends on the type of packaging and the size of defect that needs to be inspected.

Relevance of Airborne Ultrasound Technology in Seal Quality Inspection

Airborne Ultrasound technology is a non-destructive container closure integrity testing method, capable of examining seal quality for defects. Such tests are mainly conducted to provide enhanced seal quality inspection of pouches, flexible packages and tray seals. Airborne Ultrasound technology ensures in-depth seal quality analyses and is applicable for multiple packaging materials Tyvek, paper, foil, film, aluminium, plastic and poly. It is an ASTM Test Method F3004 and FDA recognized standard for seal quality testing. According to Oliver Stauffer, CEO of PTI-Packaging Technologies & Inspection, “Ultrasound is one of the only technologies that are telling us what the quality of that physical bonded nature of the seal materials are.”

Under this technology, ultrasound waves are passed through the package seal which causes reflections of sound waves. The signal strength is reduced or eliminated in the presence of a leak/ defect. Such variations are closely observed to identify the leak. Inability to detect non-leak defects is a common challenge faced by most leak test methods. However, with Airborne Ultrasound technology users can identify various types of seal defects; visible and invisible, leaking and non-leaking, process-related and random.

Latest improvements in Airborne Ultrasound Technology are in the form of Seal Scan (Offline) and Seal-Sensor. Both these technologies utilize non-contact airborne ultrasonic testing technology. Seal-Scan® technology has been proven in the field by several online and offline units installed. With the advancements in form of Seal Scan and Seal-Sensor, Airborne Ultrasound technology has been proven to be the most effective method for non-destructive seal integrity testing.

Benefits of Airborne Ultrasound technology

• Deterministic seal quality inspection technique that assures quantitative and reliable results.
• Applicable for multiple material types and combinations regardless of color, transparency, print, surface finish or porosity.
• Eliminates subjective manual inspection methods.
• Non-destructive, non-subjective, no sample preparation
• Technology can be integrated for 100% online defect detection of the final pouch seal.