← Defect Guide

Ejector Marks

Depressions, whitening, or marks at ejector-pin locations, from ejecting while the part is still soft or ejection force is too high.

◆ Common Causes

  • •Insufficient cooling (part too soft at ejection)
  • •Insufficient ejector area or count
  • •Inadequate draft angle
  • •Excessive hold pressure (part gripping the cavity)
  • •Mold surface or undercut issues

◆ Solutions

  • ✓Increase cooling time
  • ✓Increase ejector area; distribute evenly
  • ✓Add draft angle
  • ✓Reduce hold pressure
  • ✓Polish mold; remove undercuts

◆ Resin-Specific Notes

PP

Ejects while soft easily. Secure cooling.

PC

Whitens under high ejection force. Draft and polish matter.

POM

Self-lubricating and ejects well, but manage cooling.

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This content is a field-reference summary. Final judgment requires on-site engineer verification.

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