New Leak Test Method For Blister Packaging

Inspection technology specialist PTI has launched a new non-invasive inspection system at INTERPHEX for multi-cavity blister packaging made with any material, flat or glossy finish, printed or nonprinted surface, allowing fast changeover from one blister format to another.

Apart from testing the integrity of the entire blister package, VeriPac 225/BLV can detect the exact location of the defective blister cavity, setting it apart from its competitors.

Many of the available test methods for blister packages are destructive and unreliable, dependent on the properties of the package lidding material.

This is because small semi-rigid, flexible and multi-cavity blister packages do not have enough air inside the package to reliably detect defects by simple vacuum decay methods.

Water submersion testing can also be used to test small packages, yet it is destructive to both product and package, is highly subjective, unreliable and does not detect small defects.

What is more, it is impossible to use water submersion to inspect 100 percent of production.

Thus, since neither of these inspection methods will indicate which blister cavity is defective, the reliability of the test results cannot be guaranteed.

Although noncontact sensor applications are capable of detecting the location of a defective blister cavity, they are prone to false measurements and can be destructive.

The core technology of the VeriPac 225/BLV on the other hand is based on combining the ASTM-approved vacuum decay leak test method F2338-05 that was developed using PTI's VeriPac instruments with special vision imaging technology to easily identify the location of defective blister cavities.

"This is a robust system, specially designed to overcome many of the challenges involved with testing blister packaging that haven't been solved with many inspection methods used today," said Mike Kneller, R&D manager of PTI.

"Operators simply place the blister package in the test tooling, and the system recognises the test parameters/test criteria immediately, so this saves considerable time and decision making during operation."

The technology provides an entirely new method of leak detection, as its non-destructive test applies no stress to a blister seal.

Unlike other methods that keep the blister cavity form after pressure has equalised, this method deflates blister cavities that are defective, providing consistent displacement response of defective blister cavities.

A vision sensor requires only one image to determine the package quality and location of defects, and due to the consistent profile difference between a defective and non-defective cavity, detecting defects from non-defects is very effective.

The system produces several types of information including vacuum data, identification of defective blister cavities, and automatically stores data images of defects.

Test time is rapid with results available in numerical, statistical and image formats.

The operator interface is a touchscreen PC that can be networked to a printer or database for data log collection.

Source: PTI Packaging and Inspection Systems