The Workflow of a Heat Shrink Packaging Machine

The entire process is divided into seven major stages: 

Startup and Preheating → Infeed Detection → Automatic Film Feeding and Wrapping → L-Type Sealing, Cutting, and Bag Formation → Heat Tunnel Shrinking → Cold Air Cooling and Shaping → Finished Product Discharge. The entire operation is under fully automated PLC control.

I. Startup and Preheating (Pre-production Preparation)

Connect the main power supply to the machine and start the conveyor motor and the internal circulation fan within the heat tunnel;

Activate the heating elements for the sealing blade and the shrink tunnel, and set the temperature according to the film material:

POF Cross-linked Film: Sealing Blade 160–180°C; Heat Tunnel 150–180°C

PE Film (for beverage multipacks): Heat Tunnel 130–170°C

PVC Film: Heat Tunnel 110–140°C

Wait for the temperature to stabilize (approximately 5–10 minutes), then load the film roll. Adjust the tension of the film guide rollers; once a test run of the film shows no deviation, production may begin.

II. Automatic Infeed + Photoelectric Detection

Products are placed onto the infeed conveyor belt—either manually or automatically via an upstream production line—and are transported forward at a constant speed;

The machine's photoelectric sensors scan for the presence of products and transmit a signal to the control system, simultaneously triggering the film feeding and sealing/cutting actions. When no products are detected, the machine enters a standby mode to conserve both film and electricity.

III. Film Feeding and Wrapping

The film release shaft automatically dispenses the center-folded film. Multiple sets of guide rollers spread the film open, completely enveloping the product from both the top and bottom to form a loose film sleeve, thereby providing the necessary slack for subsequent heat shrinking.

IV. L-Type Sealing and Cutting (Core Bag-Making Process)

Upon reaching the sealing and cutting station, a pneumatic cylinder descends to clamp and secure the film, followed by the instantaneous descent of the L-shaped, constant-temperature sealing blade:

It seals the film edges longitudinally (along the sides);

It seals the film transversely (across the front and rear ends of the product) while simultaneously cutting the film, thereby individually packaging each product into a sealed film bag;

Excess film scraps and trimmings are automatically collected for disposal;

The surface of the sealing blade features a special Teflon anti-stick coating to prevent the molten film from adhering to the blade and to ensure that the seals do not crack. V. Hot Air Tunnel Heat Shrinking

Upon completion of the sealing and cutting process, the film-wrapped products are conveyed by a chain mechanism into an enclosed heat-shrink tunnel:

Inside the tunnel, a combination of circulating hot air and infrared heating tubes ensures uniform, omnidirectional heating of the film;

Activated by the heat, the thermoplastic film triggers its molecular memory effect, rapidly shrinking inward to tightly conform to every edge, corner, and curved surface of the product, thereby eliminating wrinkles and completing the wrapping and shaping process.

VI. Cooling and Setting

As the products exit the heating tunnel, they enter a rear air-cooling zone where powerful blasts of cold air rapidly lower the film's temperature;

Once cooled, the film's molecular structure sets in place, maintaining a taut and smooth state without rebounding or wrinkling, ensuring a stable and aesthetically pleasing package appearance.

VII. Finished Product Discharge

The fully cooled and packaged products are automatically conveyed out via a conveyor belt, ready to be collected directly by operators for immediate warehousing or boxing; with the completion of this entire cycle, the equipment automatically enters a standby mode, awaiting the next product for processing.