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Shantou Shuangli Machinery Factory
Contact: Yu Hongliang Manager
Phone: 18955651595
Phone: 86-1396-6902200
Address: Shuangli Machinery Factory, Jinping District Industrial Park, Jinping District, Shantou City, Guangdong Province, China

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15 common faults and solutions for blown film! There is always one you need~

编辑:Shantou Shuangli Machinery Factory  时间:2018-10-08

1. Uneven winding, failure analysis and troubleshooting methods:

(1) Uneven film thickness. The film thickness should be adjusted.

(2) Insufficient or uneven cooling. The cooling should be strengthened and the air volume of the air ring should be adjusted.

(3) The clamping force of the tractor is uneven, and the film is off-track. The clamping force should be adjusted so that the clamping force on the roller surface is uniform.

(4) The air in the bubble tube is entrained into the diaphragm, causing wrinkles. The clamping force of the clamp should be adjusted to remove the gas in the membrane tube.

2. Analysis and troubleshooting of bubble tube skew failure:
(1) The temperature of the body and die is too high. Should be reduced appropriately.
(2) The temperature of the head connector is too high. Should be reduced appropriately.
(3) The die output is uneven, and the film thickness is uneven. The gap between the die and the temperature of the head connector should be adjusted appropriately.
3. The bubble tube is in the shape of a reed
Failure analysis and troubleshooting methods:
(1) The regular gourd shape of the bubble tube is caused by too small clamping force of the traction roller, or the rotation speed of the traction roller is affected by the regular change of mechanical transmission resistance. In this regard, the clamping force of the traction roller should be appropriately increased, and the mechanical transmission part of the traction device should be overhauled to make the rotation speed of the traction roller stable.

(2) The irregular gourd shape of the bubble tube is due to the unstable traction speed and the excessive wind pressure of the cooling air ring. In this regard, the traction speed should be adjusted to make it run stably; the wind pressure of the wind ring should be appropriately reduced.
4. Bubble tube swing
Failure analysis and troubleshooting methods:
(1) The temperature of the melt is too high. The temperature of the fuselage and nose should be appropriately lowered. (2) The cooling efficiency of the cooling air ring is too low. The cooling efficiency of the cooling system should be improved, and the air pressure and air volume of the air ring can be appropriately increased. (3) The friction between the bubble tube and the chevron splint is too large. The angle of the herringbone should be appropriately increased to reduce the contact area between the bubble tube and the splint. (4) The temperature of the machine head is too low, the discharging is difficult, and the film bubble jumps. The temperature of the machine head and the speed of the screw should be increased appropriately.
5. Flowers on the surface of the film
Failure analysis and troubleshooting methods:
(1) The temperature of the fuselage or machine head is low, and the plasticization of the melt is poor. The temperature of the fuselage or nose should be appropriately increased.
(2) The screw speed is too fast. Should be slowed down appropriately.
(3) The screw temperature is too high or too low. The temperature of the screw should be controlled within a suitable temperature range by adjusting the flow of the cooling medium in the screw.
6. The hanging line is obvious, fault analysis and troubleshooting methods:
(1) Decomposed materials or impurities adhere to the outlet of the die. Use a copper shovel to scrape off impurities or char material, and in severe cases, eject the mandrel for cleaning.
(2) The mouth mold is bruised. The die should be trimmed.
(3) The internal pressure of the machine head is too small. The filter should be added.
(4) The temperature of the melt is too high. The temperature of the fuselage and nose should be appropriately lowered.
7. Obvious traces of seam lines
Failure analysis and troubleshooting methods:
(1) The temperature of the machine head or the machine head connector is too high. Should be reduced appropriately. But the temperature should not be too low, otherwise, seam lines will still be produced. (2) There is burnt material adhesion at the tip of the mandrel. The shape of the tip of the mandrel should be modified to make a smooth transition. (3) The design of the head mechanism is unreasonable. The head design should be modified.
8. Poor transparency
Failure analysis and troubleshooting methods:
(1) The temperature of the body or the nose is too low. Should be increased appropriately. (2) Insufficient cooling of the bubble tube. The cooling efficiency of the cooling system should be improved, the air pressure and air volume of the air ring should be increased, and the extrusion speed can also be appropriately reduced.
9. There are stiff blocks in the film
Failure analysis and troubleshooting methods:
(1) The filter screen is broken. The filter should be replaced.

(2) Improper control of molding temperature. Should be adjusted appropriately. Under normal circumstances, if the molding temperature is low, the melt will be poorly plasticized, and it will be easy for the granddaughter to sound cold.
10. Bubbles
Failure analysis and troubleshooting methods:
(1) The raw material is not fully dried and the moisture content is too high. Should be pre-dried.

(2) Cooling water leakage in the barrel or hopper. The cooling pipes and devices should be overhauled to eliminate leakage.
11. Film wrinkles
Failure analysis and troubleshooting methods:
(1) Uneven film thickness. The film thickness should be adjusted.

(2) Insufficient cooling or uneven cooling. The cooling efficiency should be enhanced or the molding speed should be appropriately reduced.

(3) The herringbone splint or traction roller is not aligned with the center of the machine head. The centerline should be recalibrated.

(4) The angle of the herringbone splint is too large. The included angle should be appropriately reduced. Sometimes, the angle of the herringbone splint does not match the diameter of the bubble tube and should be adjusted. The geometric shape of the splint should be symmetrical.

(5) The clamping force of the traction roller is uneven and the tightness is different. The clamping force should be adjusted appropriately so that the clamping force on the roller surface is evenly distributed.

(6) The winding tension is not constant. The friction of the winding friction disc should be adjusted to ensure a constant winding tension.

(7) The machine head is not installed flat. The levelness of the machine head should be corrected.

(8) The airflow outside the bubble tube is unstable. The screen should be blocked around the bubble tube to keep the airflow around the bubble tube stable.
12. Difficulties in film introduction, failure analysis and troubleshooting methods:
(1) Improper temperature control of the machine head. When the temperature of the machine head is too high or too low, it will cause difficulty in towing, and the temperature of the machine head should be adjusted appropriately.
(2) Uneven output from the die. The gap of the die should be adjusted to make the peripheral gap uniform. At the same time, properly adjust the temperature of the head connector to make it coordinate with the temperature of the fuselage. (3) The molten material contains char impurities. The raw materials should be purified and the head and screw should be cleaned.
(4) Improper control of extrusion process conditions. The process conditions should be adjusted appropriately. The extrusion process conditions of several commonly used plastic blown films are shown in Table 3-1. 13. Poor opening of the film
Failure analysis and troubleshooting methods:
(1) The temperature of the fuselage and nose is too high. Should be reduced appropriately.

(2) The clamping force of the traction roller is too large or the traction speed is too fast, and the cooling is poor. The clamping force should be reduced or the traction speed should be reduced.

(3) Poor cooling. The cooling efficiency of the cooling system should be improved.

(4) The amount of lubricant is too small. Appropriate amount of internal lubricant should be added.

(5) The amount of plasticizer is too much. Its dosage should be reduced, and high-efficiency plasticizers should be used as much as possible.
14. The frost line is too high
Failure analysis and troubleshooting methods:
(1) The temperature of the machine head is too high. Should be reduced appropriately.

(2) Extrusion is too large. The screw speed should be appropriately reduced.

(3) Insufficient cooling. The air volume of the cooling air ring should be increased.
15. The frost line is too low
Failure analysis and troubleshooting methods:
(1) The temperature of the machine head is too low. Should be increased appropriately.

(2) The amount of extrusion is too small. The screw speed should be appropriately increased.

(3) Excessive cooling. The air volume of the cooling air ring should be reduced.


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