Flow Wrapper for  Food & Non-Food in Flowpacks

Why Choose Flow Wrapping?

Flow wrappers are ideal for quickly packing solid products in flow-pack bags. In addition to individual items, you can also package several products in a single flow-pack.

Most of our customers are in the food industry. They use flow-wrapping machines to protect products from moisture and dirt. Furthermore, the packaging provides a good barrier against oxygen, thereby helping to keep the product fresh and appetising.

For example, our customers package peppers, fresh produce trays, fresh and filled rolls, fresh baguettes, muffins, doughnuts, biscuits, as well as protein bars and muesli bars.

For non-food products, horizontal flow-wrapping machines are used to pack items such as dishwasher tablets, cleaning sponges, household gloves, and FFP2 respirator masks. In addition, complete production lines can be integrated for converting and packaging wet wipes, cosmetic wipes, and napkins, including processes such as material unwinding, folding, cutting, stacking, counting, and final sealing into flow-wrapped packs or other suitable packaging formats.

Flow wrapping as a packaging process

The packaging process, called flow wrapping, happens here in a horizontal direction.

So, a flow wrapper is also called a horizontal form-fill-seal machine, a horizontal flow-pack machine, or a flow-packer.

Film feed: The flat film is unrolled from a reel by a dedicated film-feed motor and guided to the bag former through several guide/deflection rollers. In this stage, the film is frequently marked with information such as the best-before date and the batch or lot number. As standard, our systems include a ribbon printer – or, for an extra charge, a laser printer option.

Bag forming: To shape the flat film into a tubular form for bag production, it is first drawn over the bag former. Opposite film feed rollers also clamp the film ends together in this step so that the back seam can subsequently be sealed.

Product feeding: The product is fed to the bag former using a feed table. The best transport method depends on the product. Vertical conveyors or a belt conveyor can move the product. With a belt conveyor, the feed table ends at an extra infeed conveyor. This infeed conveyor is part of the flow wrapper’s main unit. It transfers the product for insertion into the film tube. With infeed pushers, they keep running until the product enters the film.

Longitudinal sealing: Longitudinal sealing refers to the sealing of the back seam. The unit consists of two sealing jaws situated between two pairs of feed rollers. On machines with film feed from above, the film feed rollers and sealing jaws are installed beneath the product run plates, so that after the film tube has been formed, the product, now enclosed in the film, can be transported on to the cross-sealing stage.

Cross-sealing: Cross-sealing refers to welding together the two ends of the bag. Besides the initial sealing of the film tube, the back end and the front end of the next flow pack are sealed within one single operation. A cutting knife positioned between the sealing jaws neatly divides the two ends from each other. A short discharge conveyor then carries the flow-pack bags from the flow wrapper to the following machine in the line or to a dedicated collection point.

Depending on the product size, different sealing methods can be used for cross-sealing on flow-wrap machines:

• Cross-sealing using rotating sealing jaws.
• Box motion method
• Intermittent sealing unit

Cross-sealing of the flow-pack using rotating sealing jaws:

This is the standard method for high speeds. The sealing jaws are mounted on two opposing shafts and rotate continuously.

• How it works: The jaws meet at the exact moment the gap between two products passes the sealing station. During rotation, the film is sealed and simultaneously cut.
• Advantages: Extremely fast and relatively simple in mechanical design.
• Disadvantages: The contact time (the time during which heat acts on the film) is very short, making it more suitable for thin films. Furthermore, the clearance height is limited as the jaws move in an arc.

Intermittent sealing unit (Intermittent Motion):

The flow wrapper operates in ‘stop-and-go’ mode here. Slower than the standard method, but more precise.

• How it works: The film feed stops briefly, the sealing jaws close vertically (like a pair of pliers), seal the seam whilst stationary, and then open again. Only then does the film continue to run.
• Advantages: Significantly wider and taller products can be packaged. Very long sealing times are possible, which is perfect for thick or complex composite films. The seal is usually of higher quality.
• Disadvantages: The speed is significantly lower than with rotary systems, as the entire process must be constantly accelerated and decelerated.

Box Motion process (Long Dwell):

The Box Motion process combines the best of both worlds: high speed and long sealing time.

• How it works: The sealing jaws move in a rectangular path (hence the name ‘Box’). They close, travel a short distance parallel to the product flow, seal whilst moving, open and return quickly to the starting position.
• Advantages: The moving jaws ensure a relatively long contact time when sealing the flow pack. Often used for ‘heavy-duty’ applications.
• Tall products: As the jaws open and close vertically (rather than rotating), the flow wrapper can package significantly taller products than with rotating sealing jaws.
• Seal integrity: Ideal for gas-tight packaging (MAP – Modified Atmosphere Packaging).
• Disadvantages: Mechanically more complex and more expensive to purchase than rotating systems.