Common Issues in Film Production and How to Solve Them

1. Film Is Too Sticky and Hard to Open

Causes:

1. The resin material is unsuitable, such as non-blown grade LDPE resin without or with an insufficient anti-blocking agent.
2. Excessive resin melt temperature, leading to high fluidity.
3. High blow-up ratio, reducing film's operability.
4. Slow cooling speed, causing the film to stick under traction roller pressure.
5. Overly fast traction speed.

Solutions:

1. Replace the resin or add an appropriate amount of anti-blocking agent.
2. Lower the extrusion and resin temperature appropriately.
3. Reduce the blow-up ratio.
4. Increase airflow to improve cooling efficiency and speed up film cooling.
5. Reduce traction speed appropriately.

2. Poor Film Transparency

Causes:

1. Low extrusion temperature causes poor resin plastification.
2. Low blow-up ratio.
3. Inefficient cooling affects transparency.
4. High moisture content in resin material.
5. Overly fast traction speed leads to inadequate cooling.

Solutions:

1. Increase the extrusion temperature for uniform plastification.
2. Raise the blow-up ratio appropriately.
3. Enhance cooling efficiency with increased airflow.
4. Dry the resin material to reduce moisture content.
5. Decrease the traction speed appropriately.

3. Wrinkled Film

Causes:

1. Uneven film thickness.
2. Inadequate cooling.
3. Excessive blow-up ratio causing bubble instability.
4. Overly large angle of the nip guide plate.
5. Uneven pressure on traction rollers.
6. Misaligned guide rollers are affecting film stability.

Solutions:

1. Adjust film thickness for uniformity.
2. Improve cooling to ensure proper film solidification.
3. Reduce the blow-up ratio.
4. Decrease the angle of the nip guide plate.
5. Balance traction roller pressure.
6. Align guide roller axes for consistent stability.

4. Film with Foggy Water Marks

Causes:

1. Low extrusion temperature causes poor resin plastification.
2. Moist resin with high water content.

Solutions:

1. Adjust and increase the extruder temperature settings.
2. Dry the resin material; the moisture content should be under 0.3%.

5. Uneven Film Thickness

Causes:

1. Non-uniform die gap causing inconsistent extrusion.
2. Uneven temperature distribution at the die head.
3. Unequal airflow from the cooling ring.
4. Improper blow-up and draw ratios.
5. Inconsistent traction speed.

Solutions:

1. Adjust the die gap for uniformity.
2. Ensure consistent temperature distribution at the die head.
3. Balance the cooling airflow.
4. Optimize the blow-up and draw ratios.
5. Maintain a steady traction speed.

6. Excessively Thick Film

Causes:

1. Large die gap and excessive extrusion.
2. Excessive cooling airflow causes rapid cooling.
3. Slow traction speed.

Solutions:

1. Adjust the die gap.
2. Reduce cooling airflow for further film expansion.
3. Increase the traction speed appropriately.

7. Excessively Thin Film

Causes:

1. Small die gap causing high resistance.
2. Insufficient cooling airflow.
3. Overly fast traction speed overstretching the film.

Solutions:

1. Adjust the die gap.
2. Increase cooling airflow.
3. Reduce traction speed appropriately.

8. Poor Heat-Sealing Properties

Causes:

1. Low dew point causing polymer molecular orientation, similar to biaxial stretching films.
2. Improperly high blow-up and draw ratios cause film stretching.

Solutions:

1. Adjust cooling airflow to slightly raise the dew point and minimize molecular stretching.
2. Reduce blow-ups and draw ratios appropriately to avoid excessive stretching in both directions.