Defect Guide

Jetting

High-velocity melt jetting from the gate creates serpentine marks on the part surface.

Common Causes

  • Injection speed too high
  • Gate size too small
  • Poor gate location (direct injection into open space)
  • Melt temperature too low

Solutions

  • Reduce injection speed (1st stage)
  • Enlarge gate size
  • Change gate location or direction
  • Raise melt temperature
  • Multi-stage injection (start slow)

Resin-Specific Notes

General

Placing a wall opposite the gate suppresses jetting.

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