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 20°C – 30°C (35°F – 55°F).
  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. Consult your technical service representative for appropriate mesh size and die clearance.
  5. If the machine is heavily contaminated and glass-filled grades (EX, PX2, NF) 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. When the purge is free of contamination, displace the remaining Asaclean 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 20°C – 30°C (35°F – 55°F).
  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. Consult your technical service representative for appropriate mesh size and die clearance.
  5. If the machine is heavily contaminated and our glass-filled grades (EX, PX2, NF) 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. If possible, bypass the accumulator to clean the screw and barrel first. If not possible, reduce the accumulator volume until the purge material from the screw appears free of contamination.
  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, and increase the accumulator’s discharge speed to maximum safe level.

Injection Blow Molding

Please follow purging procedure for injection molding.