BLOWN FILM
EXTRUSION
TROUBLESHOOTING

Unstable die head temperature

• Check the heater function is normal
• Check the thermocouple position is correct

Die head throughput fluctuations

• Adjust the die gap
• Regular cleaning of die head, screw and hilter

Non-uniform cooling air volume

• Check air ring for dirt buildup or breakage
• Adjust air ring position
• Check whether air pipe is damaged

The air flow in the factory is too fast

• Do not let outdoor air directly enter the factory

Extruder throughput instability

• Cool down the hopper throat to avoid plastic blocking
• Replace the strainer meshes of Filter to avoid blocking
• Matter of the formula

Blow-up ratio

• Use a smaller die head to increase the blow-up ratio

Improper die design or scratches

• Clear die impurities
• Fix scratches on the die head
• Avoid seams by design

Material cracking

• Change the material
• Turn down heating temperature

Inappropriate raw material formula

• Select raw materials with suitable Melt Index (MI)
• Select compatible additives

Uneven gels mix

• Use screw with a greater L/D
• Adjust the melt temperature
• Use multi-layer strainer meshes for filter, or reduce the die gap, to improve back pressure

Improper film roll storage

• Avoid piling up
• Store in a well-ventilated place

Winding tension is too high

• Adjust the winding tension

Nip roller pressure is too high

• Reduce nip roller pressure

Tubular film temperature is too high

• Increase cooling air volume of air ring
• Use cold air cooling
• Reduce die head temperature
• Equip take-up roller with waterway

Unsuitable material formula

• Add anti-phase adhesive or slippery agent

Tubular film asymmetry or swing

• Adjust the air flow of air ring
• Avoid too fast air flow inside the factory
• Use a hash-shape frame to steady the film

Inappropriate nip roller

• Align nip roller and keep it horizontally
• Avoid nip roller damages

Improper collapsing frame

• Adjust collapsing frame angle
• Adjust collapsing frame length
• Reduce friction to collapsing frame

Uneven winding tension

• Adjust the winding angle

Die head scratches

• Refinishing die scratches

Improper operating in material exchange

• Avoid overheating of the gels
• The new material should have a lower MI than the old material
• Clean the machine before exchanging the material

Melt temperature is too high or too low

• Adjust the melt temperature
• Check the heater function

Raw materials contain impurities

• Avoid dirt entering feed hopper
• Avoid using recycled materials

Uneven gels mix

• Increase back pressure
• Use screw with a greater L/D
• Avoid existence of dead corner at extruder or die head

Melt temperature is too high or too low

• Adjust the melt temperature

Improper use of additives

• Reduce color masterbatch
• Reduce waste recycling rate

Insufficient melt mix

• Add more strainer meshes of filter or reduce the die gap to increase back pressure
• Use screw with a greater L/D

Non-smooth material feeding

• Clean die head and screw & barrel
• Replace the strainer meshes of filter to avoid blockage
• Cool down the hopper
• Remove raw materials impurities

Cooling line too low

• Raise the cooling line

Inappropriate ink

• Choose the right ink

Improper use of additives

• Reduce the amount of additives
• Use the appropriate surface lubricant

Insufficient corona treatment

• Increase the treatment voltage or wattage
• Reduce the take-up speed
• Narrow the gap of the electrode
• Raise the electrode treatment temperature

Air humidity too high

• Reduce the air humidity