Essential Testing Techniques for Quality Control in Flexible Packaging

Flexible packaging offers you reliable and cost-effective protection of your products, keeping them fresh, safe and secure. But in order to ensure the integrity of your flex packaging, you need to have the right packaging testing processes and instruments in place. 

From flexible food packaging to flex packaging for medical devices and pharmaceuticals, organizations across many sectors rely on flexible packaging to keep their products in top condition through the supply chain.  

However, if you manufacture or convert plastic films that don’t match up to desired specifications, then this can be catastrophic to the success of your business in terms of financial and reputational loss. So, here’s the good news: you can perform a number of flexible packaging tests – from friction testing, hot tack strength and thickness testing, through to tear testing, coefficient of friction testing and dyne testing.  

What is flexible packaging?

Flexible packaging is any kind of packaging that easily changes its shape. It’s also known as flex packaging, and it covers pouches, containers or packages. As long as the packaging easily yields and can change shape, even once it’s filled and closed, it falls into the category of flexible packaging products.  

Sure, rigid packaging has its uses, but flexible packaging is the lightweight and popular choice for many products; from chip bags and juice containers with foil coatings to plastic cereal pouches and candy packets. You can also get flexible packaging in single or multilayer forms, allowing a combination of materials that provide the right kind of protection for your products. 

Want to find out more about flexible packaging, its uses and how to test that your choice of materials and design is fit for purpose? We’ve got everything you need to know right here. 

Learn more about our guide to creating the ultimate flexible package here! 

Types of testing used for flexible packaging

Flexible packaging tear testing

Flexible packaging tear testing measures the force required to continue the tearing of an initial cut in sheet materials. Models and weights are available to test material with a variety of strengths.  

Tear testing has been around for more than half a century, and it’s also useful when it comes to evaluating the strength of perforated materials. To carry out a tear test to measure the resistance performance of a material, first a small tear is deliberately initiated, and then it is pulled apart using a tear testing machine. Some of the tear testers that we manufacture include the TMI Büchel Elmendorf Tear Tester, equipped with an optical encoder for measuring the angular position of the pendulum during tearing. Then you could check through our portfolio of industry-leading universal testing machines.  

Flexible packaging friction testing

A friction testing device – also known as a friction tester and a coefficient-of-friction tester, makes a friction measurement of a sheet-like substrate such as paper, corrugated, plastic film or paperboard. This measurement determines the angle of inclination at which one substrate affixed to a sled will begin to slide/slip against the surface of another substrate of a similar material. 

During friction testing, an inclined plane is increased at a rate of 1.5 ± 0.5″ per second by an electric motor until the test block begins to slide. The initial movement of the sled is the slide angle or coefficient of static friction of materials. When the test block just begins to slide, a photo-optical sensor automatically stops the inclined plane, and the operator can read the slide angle result. 

A variety of factors can affect a coefficient of friction tester’s measurements, including abrasion, coatings, varnishes, printing and most importantly humidity. We have several coefficient of friction testers for you to consider, including the TMI Büchel Coefficient Friction/Peel Tester 32-76e and the TMI Büchel Slide Angle Coefficient of Friction (COF) Tester 32-25. 

Flexible packaging thickness testing

Accurate thickness testing is critical in every step of the film manufacturing and converting process to verify uniformity of the gauge across the web and in finished products. 

During manufacturing, a strip of the web is occasionally removed and checked at various points for consistency. Material that’s too thick comes with increased cost, but material that’s too thin could create finished package vulnerabilities further down the line. In the printing and converting process, thickness testing is done to verify compliance with packaging quality standards to ensure safety and integrity. 

Our catalog is thick with thickness testing devices for all types of materials, including the TQC Sheen Film Thickness Gauge for the type of film and foil commonly used in flexible packaging.  

Flexible packaging hot tack testing

Hot tack strength testing offers you a method to measure flex packaging seal-strength while the film is still semi-molten. If it’s too low, the film will not perform or run properly during the filling operation, and the package may leak product after it is filled. Hot tack testing methods are sensitive seal-strength measurements and are critical for package validation. Seal-strength data is used to measure the performance of medical packages, such as sterilized medical devices where any defects can be critical to human health. 

Some of the hot tack testing instruments we can provide include the TMI Büchel Heat Sealer and Hot Tack Base 75-50, the most precise and consistent heat sealer and hot tack tester in the flexible packaging industry. 

Flexible packaging dyne testing

Dyne Testing is a quality testing method used in many industries as a way to check a material surface and characterize how it will react with manufacturing processes. Most commonly, dyne testing is used to determine the dyne level, also known as the surface energy of a material. and the material readiness for bonding, printing, painting and coating. 

Across the Industrial Physics portfolio, we have a wide range of dyne testing devices – talk to us about the right one for your organizational needs.  

Flexible packaging bending stiffness and resistance testing

Bending stiffness is a characteristic associated with the rigidity of a material. This property is related to the modulus of elasticity of the material’s stiffness. Bending testers are designed to produce a more concise, consistent measurement for the paper industry. You’ll find organizations using bending stiffness across a variety of industries including personal products, paper, flexible films, flexible packaging and non-wovens. 

Some of the bending stiffness testers we manufacture include the TMI Büchel Bending Resistance Tester 79-56 and the TMI Büchel Crease and Board 79-15. 

The best for your flexible packaging test – just ask our customers!

As a deeply customer focused business, we love it when the organizations we work with recommend our services. This includes the work we do helping customers to test all aspects of their flex packaging.  

One example includes our collaboration with a pet care brand owned by Mars, the global multi-disciplinary conglomerate. Mars needed to correct some issues linked to inadequate calibration of their packaging testing and they came to us. 

Industrial Physics is at the forefront of change when it comes to promoting sustainability in flexible packaging – but don’t just take our word for it! In this flexible packaging testing case study you’ll learn how we’ve been collaborating with a leader in polymer technology to deliver a game-changing set of test methods suitable for WVTR (water vapor transmission rate) for biodegradable polymers.  

The best for your flexible packaging test – according to our customers

Industrial Physics has been at the forefront of testing package integrity for 100 years. Working with laboratories, manufacturers, and production lines the world over to design and manufacture instruments that test all aspects of flex packaging. 

Whether you’re exploring R&D initiatives to produce the perfect flexible packaging prototype or need to ensure exceptional quality control on your production line – as your test and inspection partner for flexible packaging products, we’ve got you! 

We’ll help you get the right test and measurement equipment in place to support your business and packaging needs. All you need to do now is get in touch! Contact us – Industrial Physics