Seal integrity plays a vital role in ensuring the quality of packaging products. Even a minute defect in the seal can initiate a leak, which can compromise the quality of the product and directly affect its shelf life. It can also result in huge financial losses to the manufacturer. That being said, manufacturers give considerable importance to conducting appropriate seal integrity tests to ensure package integrity at every stage of its lifecycle.
Seal integrity testing methods can be classified into two- Destructive testing methods and Non-Destructive testing methods. Since under Destructive methods, the packages may get destroyed, its popularity has steadily declined over the past few decades due to this waste and high cost. “There is a huge shift in the industry towards deterministic and quantitative test methods,” says 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.”
Seal quality inspection techniques offered by PTI:
Vacuum Decay technology is a non-destructive Container Closure Integrity test method, used for seal quality inspection in nonporous, rigid or flexible packages. With the ability to detect leaks down to the sub-micron level, , Vacuum Decay technology is identified as one of the most practical vacuum-based leak detection methods. Its ability to provide quantitative, reliable and repetitive test results make it ideal solution for seal quality inspection in Pharmaceutical, Medical Device and Food and Nutrition industries.
Under this method, the sample packages are first placed in a close fitting evacuation test chamber that contains an external vacuum source. The vacuum levels and changes in vacuum over a pre-determined time are closely monitored. The single or dual vacuum transducer technology is used to monitor the test chamber for both the level of vacuum as well as the change in vacuum over a predetermined test time. The changes in the absolute and differential vacuum indicate the presence of leaks and defects within the package.Over the past few years, Vacuum Decay technology has seen great advancements in the form of PTI’s PERMA-VAC technology and VeriPac FLEX Series.
The next generation PERMA-VAC technology is a single or dual vacuum transducer technology that has made the VeriPac line of test systems the most sensitive vacuum-based leak tests available in the market. It has higher test sensitivity for providing accurate and reliable results and can be applied to rigid and semi-flexible packages alike. PTI’s PERMA-VAC technology ensures the most stable test measurement ever achieved through vacuum decay.
VeriPac FLEX series is an ideal package inspection solution for dry filled pouches and flexible packaging. To accommodate different package formats and test sensitivity requirements, VeriPac FLEX series is available in several configurations with multiple test chamber sizes.
2.Airborne Ultrasound technology:
Airborne Ultrasound technology is yet another seal quality inspection technique, which is capable of non-destructively conducting advanced seal quality inspection of pouches and flexible packaging. It is capable of accommodating multiple packaging materials like Tyvek, paper, foil, film, aluminum, plastic and poly and is also proven to provide deterministic, reliable and accurate test results.
As the name suggests, this method 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. Such signal strength variations are closely monitored to identify defects if any. Its ability to evaluate seal quality even under conditions where the defect may not result in a leak, makes Airborne Ultrasound technology a practical choice for seal quality inspection across different industries.
PTI’s Seal-Scan (Offline) and Seal-Sensor (Online) are the latest advancements to the ultrasound test series. Both these technologies make use of non-contact airborne ultrasonic testing technology and have been established as one of the most effective methods for inspection of flexible package seals. Airborne ultrasound is also an ASTM Test Method F3004 for seal quality inspection.