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Purging Procedures

For Plastic Injection Molding Machines

On this page, you’ll find instructions, proven methods, best practices and quick tips for cleaning your plastic injection molding machine with ASACLEAN purging compounds.

Purging Instructions For Plastic Injection Molding Machines

Follow these step-by-step instructions when using an ASACLEAN mechanical-grade purging compound to clean your plastic injection molding machine:

  1. Check that all zones are in the proper temperature range for the grade of ASACLEAN being used.
  2. Retract the injection unit. Empty screw and barrel. Clean hopper and feed throat.
  3. Feed 1-2 barrel capacities of ASACLEAN into the feed throat.
  4. With the screw completely forward, increase the backpressure to the maximum level.
  5. After ASACLEAN begins coming from the nozzle, increase the screw speed to the maximum safe level.
  6. Drop the backpressure after the ASACLEAN coming from the nozzle is almost clean.
  7. Retract the screw and perform short, high-velocity injection shots.
  8. Repeat steps 3-7 if contaminants are still visible.
  9. Displace the ASACLEAN remaining in the machine with the next resin, again, at the maximum backpressure and maximum safe screw speed with the screw completely forward.

Purging Process Tips For Plastic Injection Molding Machines

  • ASACLEAN mechanical grades do not depend on chemical reactions. No soak time is required for an effective purge.
  • For maximum performance, ASACLEAN should not be diluted with other materials.
  • Do not use EX, PX2 or NF glass-filled grades for hot runner cleaning.

Purging Compound Grade Temperature Ranges

Grade °F °C
EX* 390-625 200-330
UP 340-570 170-300
U* 355-625 180-330
E 320-570 160-300
SX 570-700 300-370
PX2 535-790 280-420
NB 355-625 180-330
NC 355-625 180-330
NH* 355-625 180-330
NF* 355-625 180-330

*If using material between 330-360°C (625-680 °F), local ventilation is required. Please consult with your Technical Sales Representative for more information.

Tips Targeting Specific Areas Of Your Injection Molding Machine

The following purging techniques should be used after performing the procedures found above.

Nozzle or check ring hang-up  color or carbon: Raise the temperature of the nozzle 20-30°C (35-55°F). If purging a heat-sensitive resin, do not exceed the safe processing temperature of the material. Feed a small amount of ASACLEAN (less than half barrel capacity). Repeat short, high-velocity injection shots until clean.

Exercise proper safety precautions and use appropriate PPE.

For further insight into our recommended purging procedures, visit the Purging Process Resource Center. This page offers you training videos, guidelines, technical documentation and more to help answer your purging compound questions.

Ready to learn even more about ASACLEAN purging compound products and services? Click here to schedule your free, 10-minute consultation with a Purging Process Expert at ASACLEAN.

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