12 Extrusion Defects and Troubleshooting

12 Extrusion Defects and Troubleshooting

12 Extrusion Defects and Troubleshooting

Interrupted Melt Output: Unbalanced barrel temperatures

  • Reduce the feed zone temperature to feed the material to transition zone properly.
  • Checked the temperature resistance and cooling system.
  • Check the screen to catch the degraded, burned particles.

Surging: Due to contaminated material, wrong temperature settings, or an unbalanced die exit

  • Increase the barrel temperatures gradually equally for each zone.
  • Check the screen and clean if it is blocked.
  • Check for blockages in the hopper.
  • Check the screw configuration.
  • Clean the screw before production.

No Output: The die is blocked due to solidification

  • Check the material entrance from the hopper to inside the barrel.
  • There might be a blockage inside the hopper.
  • Increase the die temperature to dissolve the blockage.
  • Change the screen.

Rough Surface Due to Unmelted Particles

  • Check the screen if there are any tears.
  • Increase the temperatures especially in the compression zone.
  • Check the zone temperature resistance.
  • If there are any crosslinked particles on the surface, reduce the screw rpm and the zone temperatures in order to prevent degradation.

Burned and Discolored Extrudate

  • Reduce the screw rpm.
  • Reduce the barrel temperatures gradually until the right color is achieved.
  • Select the extruder with a lower L/D ratio for production.

Die Lines

  • Select the material with a lower viscosity.
  • Increase the die temperature.

Melt Fracture

  • Reduce the barrel temperatures.
  • Change the material in accordance with the die design.

Shark Skin

  • Reduce the rpm.
  • Change the screen.
  • Increase the melt temperature.

Fish Eyes

  • Check the material and screen for contamination.
  • The material must be dried properly before using.
  • Reduce the temperatures to prevent material degradation.

Bubbles on the Profile Surface

  • Be sure to dry the material properly.
  • Reduce the melt temperature.
  • Reduce the screw rpm.

Warpage: Insufficient cooling

  • Increase the cooling bath length, and reduce the water temperature.
  • Balance the die according to the part wall thickness.

Orange Peel Surface

  • The die temperature is too low. Increase the die temperature.
  • Increase the temperature of the zones that are close to die.