Defect Guide

Flash

Resin leaks past the parting line, ejector pins, or other mold interfaces.

Common Causes

  • Insufficient clamp force
  • Excessive injection pressure or hold pressure
  • Worn or damaged parting line surface
  • Insufficient mold rigidity
  • Melt temperature too high (viscosity drops)

Solutions

  • Increase clamp force or reduce projected area
  • Reduce injection pressure and hold pressure
  • Repair parting line surface
  • Reduce injection speed
  • Lower melt temperature

Resin-Specific Notes

PA

Low viscosity and semi-crystalline → prone to flash. Ensure sufficient clamp force.

PPS

Very flash-prone. Ensure sufficient clamp force.

LCP

Extremely low viscosity. Highest flash risk. Mold precision is critical.

PC

High viscosity, but flash possible at elevated temperatures.

PP

Low viscosity. Watch for flash.

Resins Prone to This Defect

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