 Problem |
Possible causes |
Possible solution |
| Problem at Film |
| Rough surface, Inhomogeneous surface |
| Too much output
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| Too low melt temperature
|
| Raise processing temperature |
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| Dirty Die
|
| Clean, inspect, and repair the Die |
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| MFR gap of mixing material is too much
|
| Change material or raise the mixing temperature equal to end of extruder |
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| Too low Die temp
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| Fish eyes or contaminate on film surface |
| Foreign material contaminate with resin, ex. dust, scrap.
|
| Check feeding and preparation system of resin. Check with resin producer |
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| Broken screen pack
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| Resin remaining in the extruder, Die
|
| Clean Die, remove and clean extruder, screen pack |
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| Degradation of recycle material
|
| Check the quality of the recycle and resin. Test by blowing without recycle material |
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| Material is mixed with high viscosity material
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| Change material or raise the mixing temperature equal to end of extruder |
|
|
| Wrinkles |
| Unstable bubble
|
| Make an adjustment by use of calipers and sprit level or clean Air ring |
| Clean Air ring or adjust Air ring until air flow is fixed |
|
| Extrusion surging / Unstable plastic output
|
| Check the feeding system and raise feed zone temperature if insufficient amount of Hopper ground water is occurs. |
| Check extrusion temperature if inappropriate processing temperature is occurred |
| Decrease temperature under Hopper if temperature under Hopper is too high |
|
| Improper air flow from Air ring
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| Adjust Air ring and air flow |
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| Improper pulling rate at Winder
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| Tape or contamination on Idler roller
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| Nip roll and Die is not level.
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| Inhomogeneous bubble
|
| Adjust Die temperature equal to melt temperature |
| Adjust Die |
| Clean Air ring |
|
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| Tear in machine direction |
| Blow Up Ratio is too low
|
| Increase Blow Up Ratio or replace Die with smaller size |
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| Frost line height is too low
|
| Increase height of frost line, beware on bubble unstable and other properties changing |
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| Too much Die gap
|
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| Damage on film surface
|
| Check the film surface, Clean or repair die |
|
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| Thickness variation in Transverse Direction |
| Fouling and unsatisfactory plating of the inside of the Die
|
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| Uneven ambient temperature around the Die and the bubble
|
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| Improper melt temperature
|
| Adjust the melt temperature |
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| Improper thickness control
|
| Adjust by use of the adjustment Bolt |
|
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| Thickness variation in machine direction |
| Extrusion surging
|
| Check the feeding system and raise feed zone temperature If insufficient amount of Hopper ground water is occurs. |
| Check extrusion temperature if inappropriate processing temperature is occurs. |
| Decrease temperature under Hopper if temperature under Hopper is too high |
|
| Pulsation and vibration of the bubble
|
| Reduce processing temperature if melt temperature is too high |
| Adjust rate and direction of the air from Air ring if rate of air flow from Air ring is too high |
|
|
| Vibration of the bubble |
| High melt temperature
|
| Reduce processing temperature |
|
| High rate of air flow from Air ring
|
| Adjust rate and direction of the air from Air ring |
|
|
| One sidedness - unbalanced bubble |
| Thickness variation
|
| Check and adjust the thickness |
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| Unsatisfactory alignment and level of the Air ring
|
| Check and adjust the Air ring |
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| Screen pack plug
|
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| Broken, pinholes bubble |
| Occurrence of fish eyes or gel
|
| Check feeding and preparation system of resin. Check with resin producer |
| Change new screen pack if screen pack is broken |
| Clean Die, remove and clean extruder, screen pack if find some Resin remaining in the extruder, Die |
| Check the quality of the recycle and resin if found some degradation of recycle material |
| Change material or raise the mixing temperature equal to end of extruder if material is mixed with high viscosity material |
|
| Contamination of foreign materials
|
| Check feeding and preparation system of resin. Check with resin producer |
|
| Degradation of resin in the extruder
|
| Change new screen pack if screen pack is broken |
| Clean Die, remove and clean extruder, screen pack if find some Resin remaining in the extruder, Die |
|
| Moisture material
|
| Check moisture of the material. High moisture should be dried |
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| Extrusion Surging |
| Insufficient amount of resin in hopper or in feed zone
|
| Check the feeding system and raise feed zone temperature |
|
| Inappropriate processing temperature
|
| Check extrusion temperature |
|
| Too high temperature under Hopper
|
| Decrease temperature under Hopper |
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