Open mouth bags are typically constructed of kraft (paper), poly woven mesh, plastic film or burlap. All of these bags need to be closed after filling by using a sewing head, heat sealer or pinch bag closer.
The process of open mouth bag filling begins with the placement of an empty bag on or below the fill spout of the bag scale.
For gross weighing, the fill spout of the packer is suspended from an electronic load cell that accurately weighs the amount of product in the bag.
In net weigh applications, the material is pre-weighed in scales above the open mouth bag filler, then discharged into the open mouth bag. The bag can be placed on the fill spout by hand or by an automated open mouth bag placer. Once the bag is filled, it is released and drops to the sewing conveyor belt.