1. Film Unwinding and Folding

The process begins with a large roll of printed plastic film, similar in appearance to a giant roll of paper. The film is printed with aligned patterns that include both front and back designs.

This film is carefully folded into a V-shape and layered step by step as it moves through the machine. Heat-sealing knives then seal the sides at precise intervals, forming the familiar structure of four-side-seal snack bags. At this stage, the bags resemble small upward-opening “pouches” ready for filling.

2. Printing and Cutting

During this stage, essential production information—such as batch number and manufacturing date—is applied using hot stamping or inkjet printing. This ensures traceability and regulatory compliance.

After printing, precision cutting knives separate the continuous film into individual bags. Each bag is neatly cut with intact edges and transferred by conveyor systems to the next process.

3. Bag Opening by Robotic Arms

A mechanical arm uses a negative pressure suction system to open each bag. By gently吸附 (suctioning) both sides of the bag opening and applying controlled pressure, the bag opens smoothly without deformation—preparing it for filling.

4. Nitrogen Flushing and Desiccant Insertion

To extend shelf life and maintain freshness, nitrogen gas is introduced into the bag. Nitrogen is chemically stable and does not react with food at room temperature, making it an ideal protective gas.

For snacks that are sensitive to moisture, desiccants such as quicklime, calcium chloride, silica gel, or montmorillonite may be added. These materials absorb excess moisture and further prevent spoilage, oxidation, or mold growth.

5. Automatic Weighing, Filling, and Sealing

Snacks are portioned using automatic weighing systems, ensuring consistent weight and quality in every bag.

For products like beef jerky—which are less fragile than chips or cakes—excess nitrogen may be partially extracted. This reduces package volume, improves transport efficiency, and lowers logistics costs.

Once the desired gas balance is achieved, the bag is heat-sealed at the top, completing the automated packaging process.

6. Quality Inspection and Gas Ratio Monitoring

To ensure long-term storage stability, quality inspectors conduct regular gas composition checks, typically every five minutes. The oxygen and nitrogen levels inside the bags are analyzed to detect leaks or sealing issues early.

This strict quality control guarantees that every packaged snack meets shelf-life and safety standards.

Conclusion

Snack packaging is far more than a simple container. Through thoughtful design and advanced automation, packaging becomes a powerful tool for brand communication, product protection, and cost efficiency. Four-side-seal plastic bags, combined with nitrogen flushing and precise automation, exemplify how modern snack packaging balances beauty, functionality, and reliability.
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