As the name implies, vertical form/fill/ seal (vf/f/s) machines form, fill, and seal packages in a vertical orientation. The machines convert films and other flexible substrates into bags and similar packages. The machines are used in a variety of industries, for diverse products with diverse requirements. There are similarities among users, though. The products, like liquids, powders, granulates, grains, and certain bulk items, all have flow properties. Despite their seemingly do-all nature, vf/f/s machines are not stand-alone operations. They must be integrated into a production line, between upstream and downstream operations. The integration imposes decisions in aiming for the optimal fit. A reasonable start is an understanding of certain basics about vf/f/s machines, in the sequence of the three functions. Forming. A roll of substrate is placed onto an unwinding roll. The substrate is pulled up, and then around and over rollers, to a forming collar and around a forming tube. The substate is formed into a package, the width of which is determined by the shape and size of the tube. The length of the package is determined by the programed distance in which side-positioned drive belts pull downward.
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