Processing & Design

Troubleshooting: Extrusion

Defect:
Black specks, Burning Dimensional Variation Pitting or Foaming Poor Impact and Physical Properties	Rough Appearance Surging Too Glossy

Defect: Black specks, Burning
Possible Causes:

1. Check temperatures
2. Check quality and material of construction for surfaces in contact with melt
3. Check for streamlined, low inventory die/adapter
4. Clean out all burned or foreign material from die, adapter, and extruder
5. Check that proper screw is installed

Defect: Dimensional Variation
Possible Causes:

1. Reduce screw speed

Defect: Pitting or Foaming
Possible Causes:

1. Further drying is required

Defect: Poor Impact and Physical Properties
Possible Causes:

1. Check stock temperatures

Defect: Rough Appearance
Possible Causes:

1. Check that proper screw is installed

Defect: Surging
Possible Causes:

1. Reduce screw speed
2. Eliminate screw cooling

Defect: Too Glossy
Possible Causes:

1. Reduce screw speed
2. Reduce barrel temperature
3. Check that proper screw is installed