← Defect Guide
Gate Blush
A hazy, dull halo on the surface just past the gate, caused by excessive shear at the gate.
◆ Common Causes
- •Injection speed too high at the gate (over-shear)
- •Gate too small → rapid pressure drop
- •Mold temperature too low
- •Excessive gate land length
- •Valve-gate pin wear or timing issue (hot runner)
◆ Solutions
- ✓Slow injection speed through the gate (multi-stage profile)
- ✓Enlarge the gate; shorten the land length
- ✓Raise mold temperature
- ✓Check and raise hot-runner gate temperature
- ✓If intermittent and process-independent, inspect valve-pin tip and stroke
◆ Resin-Specific Notes
Heat-resistant ABS
Sensitive to gate over-shear. Slow the speed first.
PC
High viscosity. Gate temperature and speed control matter.
PC/ABS
Gate blush is common. Review gate design and speed.
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This content is a field-reference summary. Final judgment requires on-site engineer verification.