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Purging Procedures for Hot Runner Open/Closed Mold


  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. Check with your hot runner supplier to insure the system can be purged through with the mold open without causing damage.
  3. Protect the “B” half of the mold so that pins, polish doesn’t come into contact with hot extruded purge.
  4. A minimum of a .030 gate is required for proper purging Hot Runner in open position.


  1. Refer to purging procedure on standard or vented barrel. Steps 1-8 need to be completed before attempting to purge the Hot Runner.
  2. Protect the “B” half of the tool as noted on safety procedures #3 above.
  3. Make sure the nozzle and sprue bushing are clean of molten plastic.
  4. Move the Injection unit forward until it seats with the mold.
  5. With the injection unit at full capacity with MAGNA PURGE® begin purging through the open mold until it’s a white to clear and clean.
  6. Retract the injection unit and follow purging procedures 9-11 for purging MAGNA PURGE® out of the barrel and prepare for next resin.
  7. Proceed with your set up for next production resin.


  1. Follow same safety procedures above. #1 and #4 on minimum gate size.
  2. Refer to purging procedures on standard or vented barrel. Steps 1-8 need to be completed before attempting to mold MAGNA PURGE™ in Hot Runner.
  3. Begin molding parts with MAGNA PURGE® until all parts are clean.


  1. It may be necessary to raise manifold and tip temperature by 50°F to 80°F, consider operating temps for resin to be removed and MAGNA PURGE®.
  2. MAGNA PURGE® can be safely processed from 360°F -610°F. Idea temps are 410°F-460°F.
  3. For extreme contamination such as carbon, liquid color or highly loaded pigments in colorants you may consider using a HDPE or PP to pre-purge prior to using MAGNA PURGE®.
  4. One of our glass grades may also be considered, consult with our technical team.

***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.