The liquid vertical form fill seal machines adopt man-machine dialogue, which can conveniently and accurately adjust the bag size and packaging speed. The packaged materials fall into the packaging bag through the metering device. There are many metering methods, including gear click, peristaltic pump, pneumatic plunger type, and so on. The cutter also has a flat knife, sawtooth knife, fillet knife, and so on. The liquid form fill and seal machines can also be equipped with a seal knife with the function of easy tearing opening for convenient bag opening.