As a film blowing manufacturer, it is a common phenomenon to change the film formula and produce films of different specifications. In this process, various emergencies and on-site film blowing lead to quality problems due to various reasons. By collecting the most common faults and causes in the film blowing process, New Tianhe Plastics proposes the following points to solve production problems.

1. The film is too sticky and has poor opening

1. The type of resin raw material is wrong, it is not a film-blown low-density polyethylene resin, which does not contain an opening agent or the content of the opening agent is low;

2. The temperature of the molten resin is too high and the fluidity is too large;

3. The inflation ratio is too large, resulting in poor opening of the film;

4. The cooling speed is too slow, the film cooling is insufficient, and mutual bonding occurs under the action of the traction roller pressure;

5. The traction speed is too fast.

Second, the film transparency is poor

1. The extrusion temperature is low and the resin plasticization is poor, resulting in poor transparency of the blown film;

2. The inflation ratio is too small;

3. The cooling effect is not good, which affects the transparency of the film;

4. The moisture content in the resin raw material is too large;

5. The traction speed is too fast and the film cooling is insufficient.

3. The film is wrinkled

1. The thickness of the film is uneven;

2. The cooling effect is not enough;

3. The inflation ratio is too large, causing the film bubble to be unstable, swinging back and forth from side to side, and prone to wrinkles;

4. The angle of the splint is too large, and the film bubble is flattened in a short distance, so the film is also prone to wrinkles;

5. The pressure on both sides of the traction roller is inconsistent, one side is high and the other is low; 6. The axes between the guide rollers are not parallel, which affects the stability and flatness of the film, resulting in wrinkles.

4. The film has fog-like water marks

1. The extrusion temperature is low and the resin plasticization is poor;

2. The resin is damp and the moisture content is too high.

Fifth, the film thickness is not uniform

1. The uniformity of the die gap directly affects the uniformity of the film thickness. If the die gap is not uniform, some parts have larger gaps and some parts have smaller gaps, resulting in more or less extrusion. The thickness of the formed film is also inconsistent, some parts are thin, and some parts are thick;

2. The temperature distribution of the die mouth is uneven, with high and low, so that the thickness of the film after blowing is uneven;

3. The air supply around the cooling air ring is inconsistent, resulting in uneven cooling effect and uneven thickness of the film;

4. Inappropriate inflation ratio and traction ratio make it difficult to control the thickness of the film bubble;

5. The traction speed is not constant and changes constantly, which will of course affect the thickness of the film.

Sixth, the thickness of the film is thick

1. The die gap and extrusion volume are too large, so the film thickness is too thick;

2. The air volume of the cooling air ring is too large, and the film is cooled too fast;

3. The traction speed is too slow.

7. Thin film thickness

1. The die gap is too small and the resistance is too large, so the film thickness is too thin;

2. The air volume of the cooling air ring is too small, and the film cooling is too slow;

3. The traction speed is too fast, the film is stretched too much, and the thickness becomes thinner.

8. Poor heat sealability of the film

1. The frost line is too low, and the polymer molecules are oriented, so that the performance of the film is close to that of the oriented film, resulting in a decrease in heat sealing performance;

2. If the inflation ratio and the traction ratio are too large, the film will be stretched and oriented, thus affecting the heat sealing performance of the film;

Nine, film longitudinal tensile strength is poor

1. The temperature of the molten resin is too high, which will reduce the longitudinal tensile strength of the film;

2. The inflation ratio is too large and does not match the traction ratio, so that the orientation effect and tensile strength of the film in the transverse direction are improved, while the tensile strength in the longitudinal direction will be deteriorated;

3. The cooling rate of the film is too fast;

4. The pulling speed is slow, and the orientation of the film in the longitudinal direction is not enough, so that the longitudinal tensile strength is deteriorated.

10. The transverse tensile strength of the film is poor

1. The cooling speed of the cooling air ring is too slow;

2. The traction speed is too fast, and the difference with the inflation ratio is too large, which will cause fibrillation in the longitudinal direction, and the transverse strength will be deteriorated.

Eleven, the membrane bubble is unstable

1. The extrusion temperature is too high, the fluidity of the molten resin is too large, and the viscosity is too small, which is prone to fluctuations;

2. The extrusion temperature is too low and the output is small;

3. The air volume of the cooling air ring is unstable, and the cooling of the film bubble is uneven;

4. It has been disturbed and influenced by strong external airflow.

12. The surface of the film is rough and uneven

1. The extrusion temperature is too low, and the resin plasticization is poor;

2. The extrusion speed is too fast.

Thirteen, the film has peculiar smell

1. The peculiar smell of the resin raw material itself;

2. The extrusion temperature of the molten resin is too high, causing the resin to decompose, resulting in peculiar smell;

3. The cooling of the film bubble is insufficient, and the hot air in the film bubble is not removed cleanly.