Blow Molding

The ASACLEAN purging compound grade for your blow molding process depends on your thermoplastic resin and its processing temperature.  Extrusion Blow Molding processes are classified as either “Extrusion blow” or “Accumulator blow”.

Contact a technical representative for proper grade selection for use in your specific blow molding application.

Extrusion blow

  1. Raise the temperatures of the die about 68°F – 86°F (20°C – 30°C).
  2. Extrude the remaining resin from the system.
  3. Clean the hopper and feed throat.
  4. For unfilled grades of ASACLEAN, screens and dies may be left in place for purging.
  5. If the machine is heavily contaminated and our glass-filled grades (EX / PX) are required, remove the screen pack to prevent plugging. Remove the die as well, if necessary (recommended for highly polished surfaces).
  6. Feed the required amount of ASACLEAN into the hopper.
  7. Start purging at low screw speed first; increase the screw speed to the maximum safe level after material begins coming out from the head.
  8. Periodically stop the screw and allow the ASACLEAN to sit for a few minutes. Resume screw rotation at maximum safe screw speed.
  9. Displace the ASACLEAN remaining in the machine with the next processing resin, using the same procedure above.
  10. Change the machine parameters back to normal processing conditions.
  11. Replace screen pack with a clean one.

Accumulator blow

  1. Raise the temperatures of the die about 68°F – 86°F (20°C – 30°C).
  2. Extrude the remaining resin from the system.
  3. Clean the hopper and feed throat.
  4. For unfilled grades of ASACLEAN, screens and dies may be left in place for purging.
  5. If the machine is heavily contaminated and our glass-filled grades (EX / PX) are required, remove the screen pack to prevent plugging. Remove the die as well, if necessary (recommended for highly polished surfaces).
  6. Feed the required amount of ASACLEAN into the hopper.
  7. Start purging at low screw speed first; increase the screw speed to the maximum safe level after material begins coming out from the head.
  8. Periodically stop the screw and allow the ASACLEAN to sit for a few minutes. Resume screw rotation at maximum safe screw speed.
  9. If machine allows, increase back pressure to at least 80-90%.
  10. Fill the accumulator head
  11. Purge out 25% ASACLEAN from accumulator then refill back to 100%
  12. Purge out 50% ASACLEAN from accumulator then refill back to 100%
  13. Purge out 75% ASACLEAN from accumulator then refill back to 100%.
  14. Purge out 100% ASACLEAN.
  15. Displace the ASACLEAN with the next processing resin, using the same procedure above.
  16. Change the machine parameters back to normal processing conditions.
  17. Replace screen pack with a clean one.

Notes: Increase the accumulator’s discharge speed to maximum safe level.

Injection Blow Molding

Please follow purging procedure for injection molding.