Maintenance & Reliability · SOP

End Of Line Stretch Wrapper Film Threading And Tension Setting

This standard operating procedure describes the safe, repeatable process for threading stretch film through an automated end-of-line stretch wrapper and calibrating tension parameters to ensure consistent load containment and minimal film waste.

Estimated Time

20 min

Difficulty

Intermediate

Regulation

ANSI/PMMI B155.1

Version

1.0

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Purpose

To establish a standardized method for threading and tension adjustment on end-of-line stretch wrappers, reducing film breaks, eliminating load shift incidents, and minimizing unplanned downtime. Proper tension settings improve film yield and ensure regulatory compliance for shipped loads.

Scope

This procedure applies to all automated rotary arm and turntable stretch wrappers equipped with powered pre-stretch carriages. It covers both manual (dial/spring) and electronic (touchscreen) tension control systems. Operators and maintenance technicians must complete approved training before performing this task.

Safety Precautions

LOTOLockout/tagout the wrapper at the main disconnect. Verify zero energy by pressing any start button and checking for power.
PPEWear cut-resistant gloves, safety glasses, and steel-toed boots. Film edges can cause lacerations; pinch points exist at rollers and dancer arms.
PINCHKeep hands and loose clothing away from the pre-stretch carriage, tension rollers, and rotating turntable. Film can snap violently if tension releases unexpectedly.
ELECOnly qualified personnel may open electrical enclosures. Do not bypass interlocks or safety guards during threading.

Required Tools & Materials

Stretch film roll (correct gauge and width per packaging specs)
Cut-resistant gloves
Utility knife (with retractable blade)
Film tail clamp or adhesive tape
Hex key set (for mechanical tension adjusters)
Torque wrench (if pneumatic pre-stretch) – optional
Lockout/tagout kit
Machine-specific path diagram (if not labelled on frame)

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Procedure: Step-by-Step

1 Lockout/Tagout. Isolate the wrapper from all energy sources (electrical and pneumatic). Apply lock and tag at main disconnect. Press any start button to confirm zero energy state.

2 Inspect the film carriage. Remove spent roll and any debris. Check dancer arm bearings, tension rollers, and pre-stretch belts for wear or damage. Replace if necessary.

3 Load new film roll. Align the roll with the unwind shaft, push fully onto the mandrel, and lock in place. Verify the film unwinds from the top of the roll toward the load (counter‑clockwise).

4 Thread the film path. Route film over the dancer arm, under the tension roller, through the pre-stretch carriage (between the two stretch rollers), and finally to the film clamp. Follow the machine path diagram if painting on the frame is worn.

5 Secure the tail. Wrap the film tail around the core or use the built-in film clamp. Rotate the carriage manually one full revolution to confirm smooth tracking and no snags.

6 Set tension parameters. On a touchscreen controller, navigate to the tension screen and set the pre-stretch percentage (typically 200–300%) and film tension (10–30 N). For mechanical systems, use the hex key to adjust the spring preload or air regulator to 20–40% of max pressure.

7 Run test cycle. Place a simulated pallet load. Initiate a manual wrap cycle without load. Observe film stretch: uniform elongation with no necking or tearing. Test with load if available.

8 Fine-tune tension. Increase tension if film is loose or load is unstable; decrease if film breaks at the start. Adjust in small increments (5% or 2 N). Document final settings on the machine log or clipboard.

9 Restore power. Remove LOTO devices, inform operators, and power up the wrapper. Run one full production load to confirm settings. Sign off the PM checklist.

End Of Line Stretch Wrapper Film Threading And Tension Setting

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