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Purging Procedures for Blow Molding/Preform


  1. Always follow safety procedures before performing start up or shut down on ANY material. It is the machine operator’s responsibility to wear the appropriate protective equipment such as gloves and safety shields.
  2. If the Extruder is equipped with a vented barrel; clean the area around the vent and the plug before sealing. You will need to monitor the upstream pressures.


  1. Maintain resident temperatures when using MAGNA PURGE®
  2. Run the extruder empty by shutting off feed throat on existing resins, colorants and additives.
  3. Clean the hopper, feed throat and loader hoses thoroughly.
  4. Remove the screen packs. Ensure that the die opening is at least .030 inch.
  5. Begin purging 2 times the barrel capacity with MAGNA PURGE®. Amount needed depends on condition of equipment.
  6. Purge should be rising, swelling or bubbling to insure you’re getting the maximum effectiveness.
  7. Purge through the die opening until the MAGNA PURGE® is clean to white and free of contamination.
  8. Introduce your next production resin to flush out the MAGNA PURGE®.
  9. Clean your die surface and install a new or clean screen pack.
  10. Re-adjust your die if necessary.
  11. You are now ready for production run.


  1. Follow safety procedures #1 and #2 above.
  2. Follow procedures #2 and #3 above on cleaning and removal of existing resin.
  3. Increase Accumulator temperature by 50°F.
  4. Allow for at least 3 times accumulator capacity with MAGNA PURGE®.
  5. Load the accumulator full with MAGNA PURGE®. If the equipment is designed with more than one accumulator, each accumulator needs to load with MAGNA PURGE® and temperatures raised.
  6. Center your die and open the vale gap to ½ mm.
  7. Allow MAGNA PURGE® to soak 30-45 minutes.
  8. With the valve gap open to its maximum, empty MAGNA PURGE® from the Accumulator with one continuous purge.
  9. After the MAGNA PURGE® has been displaced with the next resin you are ready for production.


  1. Consult with your MAGNA PURGE® technical team to determine which grade would be most effective
  2. For extreme contamination such as carbon, liquid color or highly loaded pigments in colorants you may want to consider using a HDPE or PP to pre-purge prior to using MAGNA PURGE®. Raising the temperatures 15° F on the soak time could also prove to be helpful.

***Notice: The information herein is based on what we believe to be reliable data, but World Class Technologies MAKES NO WARRANTIES EXPRESS OR IMPLIED, including, but not limited to, the implied warranties or merchantability and fitness for a particular purpose. Because WCT has no control over the use to which others may put the product, it does not suggest or represent that the same results as these referred to herein will be obtained by another user. Each user of the product and the compositions mentioned herein should make his or her own tests prior to purchase to determine the product's suitability for his or her own particular uses. Nothing contained herein is to be construed as a recommendation for the use in violation of any existing patent, foreign or domestic, or of applicable laws and regulations.