How can the sprue breakage be avoided when the mold is opened?

Possible cause:

• Sprue is overloaded or not optimally designed

Remedies:

• Polish sprue bushing
• Make sure sprue bushing is conical and oversized in comparison with the nozzle
• Enlarge ejector or the undercut around it
• Round off Z-shaped ejector slightly to prevent sprue from breaking at this point
• Prolong cooling time
• Reduce injection pressure
• Reduce holding pressure

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