Film Tension Problems: Diagnosis

Problem

The web pulsates, jerks or surges instead of running smoothly between the reel and the forming area. Symptoms appear downstream as intermittent tracking drift, unstable registration, or wrinkles that come and go with the pulsing.

Possible Causes

1. Tension settings do not match the current film's specification.
2. Reel braking or the tension control element responds unevenly.
3. Rollers drag due to contamination or bearing condition.
4. Acceleration and deceleration dynamics snatch the web.
5. A new reel diameter changes the web's entry behavior until re-adjusted.

What to Check

• STEP 1Watch the web at steady speed.Observe the film between rollers for rhythmic pulsing, snatch marks or momentary slack.
• STEP 2Compare settings with the machine manual.Verify tension-related settings against the documented values for the current film.
• STEP 3Check roller rotation.Locked out per procedure, rotate each roller by hand where accessible: smooth, quiet rotation is expected.
• STEP 4Observe speed transitions.Watch the web specifically during acceleration and deceleration, where tension faults concentrate.
• STEP 5Re-check after a reel change.Confirm the behavior again after loading a new reel to separate reel-dependent effects.

Corrective Actions

• Restore the documented tension settings for the qualified film and store them in the recipe.
• Clean or service rollers that show drag, and record the intervention.
• Re-verify tension at production speed after every adjustment — behavior at creep speed is not conclusive.
• Keep reel changes on the verification routine: center, lock, restore tension, run slow, confirm.