A Gelbo Flex Tester is a tool that we use to see how well packaging materials can bend without breaking. It tests things like plastic wraps, laminates, and special sheets that keep things fresh.

The Gelbo Flex Tester is made to copy the handling that packaging materials go through when they are being made, sent to stores, and used by people, like being squeezed, twisted, and bent, to make sure the Gelbo Flex Tester can tell us how strong the packaging materials really are, especially the flexible ones.

How the Test Works

A Gelbo Flex testing machine tests a piece of film, usually 200 mm by 280 mm, to a repeated mechanical action that damages it.

One complete cycle has two movements:-

• Twisting Motion: The machine twists the film sample at a 400° or 440° angle to copy the stress that happens when something is twisted. The film sample goes through this twisting motion. The machine does this to see how the film reacts to being twisted.
• Horizontal Compression: This is what happens after the twist. It is like a squeeze from the side. The machine moves in a motion kind of like stroking, and it does this over a distance of either 80 millimeters or 155 millimeters. This squeezing action is what happens to the material.

The machine does this a lot. 45 times in one minute. It keeps doing it and doing it, which makes the material bend and fold over and again. This keeps happening until the material gets really tired and cannot take it anymore.

Why is the Glebo Flexing test important?

The packaging material flex test is important to find out if it is suitable for protection and has the necessary standards and properties. The people who work in testing laboratories usually use two ways to figure out how well the material did.

• Pinhole Detection: We put the material on top of some paper, and then we brush a special colored dye, like toluidine blue or turpentine, all over the material. When the film bends, it can get cracks or small holes. These cracks and holes let the liquid get to the paper underneath, so we can easily see how many there are.
• Barrier property lost: The film that has been stressed is then put in a machine to see if it still works properly. We want to know if the bending and stretching have affected how well the film keeps out oxygen and water vapor. This is measured by checking the Oxygen Transmission Rate and the Water Vapor Transmission Rate of the film.