ASACLEAN INJECTION MOLDING PURGING INSTRUCTIONS for Transitions from High Heat Resins to Other Resins Above 360°C(680°F) to below 300°C(570°F)

  1. Upon completion of the molding operation, run the high heat resin from the machine, emptying the barrel. Clean the hopper and feed throat.
  2. Feed about 1 barrel capacity of ASACLEAN SX into the hopper.
  3. With the screw completely forward, increase back pressure to a moderate level (enough to keep the screw forward). Note: If processing temperatures are at or near the maximum recommended temperature for the SX Grade, low to medium backpressure and screw speed are recommended. Backpressure and screw speed can be increased at lower temperatures within the recommended range to maximize cleaning.
  4. Start to extrude the ASACLEAN SX at a slow screw speed. When it starts coming out of the nozzle, increase the screw speed to a moderate level (about 50% of the maximum).
  5. Drop the temperatures to below 370°C (700°F), while purging with the ASACLEAN SX. ASACLEAN SX should not be left at temperatures above 370°C (700°F), for more than 30 minutes as decomposition may occur.
  6. Continue adding ASACLEAN SX, following the above instructions until the purge pile is clean.
  7. When all temperatures are below 370°C (700°F) and the purge pile appears clean, stop the screw. Leave the barrel full of ASACLEAN SX to prevent oxygen from entering the barrel that will accelerate material decomposition and carbon formation.
  8. Wait until all temperatures drop to between 600°F and 620°F, (315°C – 325°C). The temperatures should not be allowed to drop below 570°F (300°C) with ASACLEAN SX in the barrel. Overloading of the screw may occur at temperatures below 570°F (300°C), when screw rotation resumes.
  9. Begin feeding the lower-temperature ASACLEAN grade and drop the temperature settings to the processing temperature of the lower heat resin. After all of the ASACLEAN SX has been displaced by the lower-temperature grade, leave the barrel full of the lower-temperature grade and stop the screw. The lower-temperature grade will have a slightly different appearance. The lower-temperature grade should not be left at temperatures above 570°F (300°C), for more than 30 minutes as decomposition may occur.
  10. When the temperature drops into the processing range of the lower heat resin, empty the ASACLEAN from the barrel. Then start feeding the next resin to be processed.
  11. Displace the ASACLEAN with the next resin following the standard purging procedure using the maximum safe back pressure and screw speed with the screw completely forward.
  12. After all of the Asaclean has been displaced, begin production using the normal processing conditions for the resin.