Professional Plastic Packaging Machine Manufacturer - Bonada Machinery
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Professional Plastic Packaging Machine Manufacturer - Bonada Machinery
Question 2: Bubble jumping up and down (respiratory phenomenon)
Reason:
· Wind ring air volume fluctuation
· Unstable extrusion volume (screw pulsation)
· Temperature fluctuation of cooling air
Countermeasure:
· Check the stability of the fan frequency converter
Check the wear of screws and gearboxes
Stable cooling air temperature (fluctuation<± 1 ° C)
· Question 3: The membrane bubble is biased towards one side
Reason:
One side of the lip gap of the mold head is too large
The air volume on one side of the wind ring is too high
The mold head is not installed horizontally
Countermeasure:
Check and adjust the uniformity of the lip gap of the mold head with a feeler gauge
Adjust the air volume in each area of the wind ring
Calibrate the installation of the mold head with a level gauge
· Question 4: Membrane Bubble Collapse
Reason:
Insufficient melt strength (commonly seen in low melt strength materials such as PBAT and mPE)
Excessive inflation ratio
Insufficient cooling
Countermeasure:
Reduce the inflation ratio to the recommended material range (PE generally 2.0-3.5, PBAT generally 1.5-2.5) (Source: BASF ecoflex) ® Processing Guide）
Reduce extrusion temperature to improve melt strength
• Increase cooling air volume or use IBC system
Question 5: Bubble rupture (frequent membrane breakage)
Reason:
Impurities or gel in raw materials
There is carbon buildup or damage on the lip of the mold head
The traction speed is too fast
Material degradation
Countermeasure:
Increase the number of filter mesh (recommended ≥ 120 mesh)
Clean the lip of the mold head
Reduce traction speed appropriately
Check if the processing temperature is too high
· Question 6: Unstable frost line height
Reason:
Fluctuations in cooling air volume
Fluctuations in extrusion volume
Environmental temperature changes
Countermeasure:
Stabilize the operating parameters of the fan
Inspect the temperature stability of the screw metering section
Maintain workshop temperature fluctuations within <±3°C
Question 7: Frost line height is too high
Reason:
Insufficient cooling air volume
The extrusion temperature is too high
• Slow crystallization rate of materials
Countermeasure:
• Increase cooling air volume
• Reduce the extrusion temperature appropriately
· For materials with slow crystallization (such as PBAT), this is a normal phenomenon and there is no need to forcefully reduce it
Question 8: Frost line height too low
· Reason:
• Excessive cooling air volume
• The extrusion temperature is too low
• Fast material crystallization speed
Countermeasure:
• Reduce the cooling air volume appropriately
• Increase the extrusion temperature
Attention: Low frost line may lead to a decrease in the mechanical properties of the film
Question 9: Inconsistent diameter of membrane bubbles (conical membrane bubbles)
Reason:
Improper ratio of air volume at the upper and lower air vents of the wind ring
Uneven temperature distribution of the mold head
• Unstable pressure in IBC system
Countermeasure:
Adjust the ratio of the upper and lower air vents of the wind ring (usually the lower air vent accounts for 60% -70%)
Optimize the temperature distribution of the mold head
Check the IBC system
Question 10: There is condensation of water vapor inside the membrane bubble
Reason:
IBC inlet air moisture content is too high
• High environmental humidity
Low cooling air temperature leads to dew point problem
Countermeasure:
IBC air inlet installation with dehumidification device
Workshop dehumidification
• Properly increase the temperature of the cooling air
