How vertical form, fill and seal bagging technology works:
The process starts with a cylindrical roll of film, the vertical bagging machine will transfer film from the roll and thru the forming collar (sometimes referred to as tube or plow).
Once transferred thru the collar the film will then fold where upon the vertical seal bars will extend and seal the back of the pouch.
Once the desired pouch length is transferred it is filled with product. Once filled the horizontal seal bars will then close, seal and cut the pouch providing a finished product that includes a bag with top/bottom horizontal seals and one vertical back seal.