Biaxially oriented polypropylene film is made by stretching a polypropylene film in two directions. These two operations are usually described as machine direction stretching and transverse direction stretching. Although both are used...
Which Packaging Materials Need Water Vapor Testing
Water vapor can move through packaging even when the package looks completely intact. A film may have no visible holes, tears, or open seals, yet moisture can still pass through the material...
Why Does Film Drift During Flexible Packaging Slitting
Film slitting looks straightforward from the outside. A wide roll enters the machine, the web passes through a series of rollers and knives, and narrower rolls come out the other side. Yet...
How Does Resin Temperature Affect Extrusion Lamination
Extrusion lamination can look fairly simple from the outside. A molten polymer layer is placed between or onto flexible substrates, the layers come together, and the resulting structure is wound for further...
What Problems Can Excessive Flexographic Printing Pressure Cause
Flexographic printing depends on light, controlled contact. The plate must receive ink from the anilox roll and transfer it to the substrate, but neither contact point should be pressed harder than necessary....
How Is Tensile Strength Tested in Packaging Film
Packaging film can look smooth, clean, and uniform on a production roll, but appearance alone does not show how well it will handle pulling, stretching, or tension during use. A film may...
How Do Three Side Seal and Four Side Seal Bags Differ
Three side seal bags and four side seal bags can look quite similar when they are lying flat on a production table. Both are made from flexible packaging material, both can be...
How Do Dry and Wet Lamination Differ in Production
Dry lamination and wet lamination are both used to join flexible packaging materials, but the two processes do not behave in quite the same way on the production floor. At a basic...
Why Is Gravure Ink Transfer Uneven
Uneven ink transfer can be frustrating in gravure printing. One part of the printed film may look darker, while another part looks lighter. A solid area may appear patchy, a fine image...
How Does Melt Temperature Affect Cast Film Extrusion
In cast film extrusion, melt temperature is one of those production conditions that can quietly change the whole process. The film may still come out of the die, but its appearance, thickness,...
Why Is Film Thickness Uneven During Blown Film Extrusion
Film thickness can look simple on a production sheet, but keeping it even during blown film extrusion is not always easy. A roll may appear normal at first glance, yet small differences...