How to Use Shrink Film: Equipment, Steps, and Practical Tips

Overview

Shrink film packaging is simple in concept but requires attention to material, equipment, and process settings for reliable results. This guide walks beginners through common equipment, the step-by-step process, and practical tips to avoid frustration.

Common equipment

• Heat gun: Handheld, versatile for small runs or irregular shapes. Easy to use but slow for production volumes.
• Shrink tunnel: A conveyorized oven that provides consistent, even heat for high-volume packaging. Tunnels can be adjusted for temperature, conveyor speed, and airflow.
• L-sealer (impulse sealer): Seals and cuts film to form a bag around the product; often paired with a shrink tunnel.
• Fold/flow wrappers and sleeve applicators: Machinery that automates film wrapping, feeding, and forming sleeves around products before shrink heating.
• Sealing jigs and tables: For semi-automated lines, these help position products and create consistent seals.

Step-by-step process (typical for a small to medium packaging line)

1. Select the right film and size: Choose material (e.g., polyolefin for food), film thickness, and form (sleeve, cut sheet, roll). Allow some oversize so the product is fully covered.
2. Prepare the product: Clean and, if needed, pre-position items in trays or on pallets. Remove labels or dirt that could affect film adhesion.
3. Wrap or form the package: For sleeves, slide the pre-cut sleeve over the product. For sheet film, place the product on the film and use an L-sealer to form a sealed bag with trimmed excess.
4. Heat application: Move the wrapped product through a shrink tunnel at settings matched to the film—temperature, dwell time, and conveyor speed all matter. For manual jobs, use a heat gun and move it uniformly around the package.
5. Cooling and inspection: Allow the package to cool briefly so the film sets. Inspect for even shrink, wrinkles, seals, and any product damage.

Key machine settings and how to approach them

• Temperature: Different films require different shrink temperatures. Polyolefin typically shrinks between 120–220°C depending on thickness and orientation, whereas PVC shrinks at lower temperatures. Consult film specs and start low, increasing in small increments.
• Conveyor speed/dwell time: The product must spend enough time in the controlled heat zone for even shrink. Slower speeds increase dwell time and shrink quality.
• Airflow and distribution: Even heat distribution prevents hot spots and uneven shrink. Shrink tunnels often have adjustable air knives or fans to direct heat where needed.

Practical tips for beginners

• Test first: Run tests with spare products to determine optimal temperature and speed. Document settings for repeatability.
• Use oven-safe product placement: Avoid packaging heat-sensitive items without testing; batteries, electronics, and some adhesives can be damaged by heat.
• Watch for breathing room: For delicate or oddly shaped items, insert a light backing or inner tray to prevent distortion during shrink.
• Avoid trapping air: Air pockets can create bubbles and interfere with seal integrity; smooth film around edges before heating.

Troubleshooting common issues

• Film wrinkles or loose areas: Increase tunnel temperature or slow conveyor for more dwell time; ensure film size is correct.
• Film tearing or pinholes: Film may be too thin for the package, or temperature too high for thin spots. Use thicker film or lower heat.
• Discolored or melted product: Heat is too intense or concentrated in one area. Use gentler airflow, lower settings, or add insulating trays.
• Poor seal strength: Check L-sealer condition and impulse settings; ensure sealing bars are clean and Teflon covers intact.

Safety and housekeeping

• Ventilation: Some films can emit fumes if overheated. Ensure good ventilation and use films appropriate for the product and environment.
• Operator training: Teach correct grip, heat gun angles, and safe distances from hot surfaces and moving conveyors.
• Fire prevention: Keep flammable materials away from heat sources and maintain equipment to avoid electrical faults.

Real-world example

A small e-commerce retailer uses an L-sealer and a compact shrink tunnel to produce neat, tamper-evident packages for a wide variety of items. They maintain a short testing log for each new product to record optimal tunnel temperature and belt speed, which reduced packaging defects by 80% within a month.

Closing advice



Start with small trials to dial in film type and machine settings. Keep clear records of successful settings and standardize packaging methods to improve speed and reduce waste. With simple equipment and good process control, shrink film delivers professional-looking, protective packaging suitable for many applications.