20.6.17 Streaks
The nished product has large, dull and laminate appearance areas on the
surface.
Probable Cause:
1. Molding Machine
• Back ow valve ring damaged
2. Mold
• Hot spots
• Material trapped in certain areas
3. Material
• Contamination of resin or machine
• If pattern is identical, cause may be the machine
• If pattern is erratic, cause may be the material or coloring
• Degraded or unstable material
Solution (in sequence):
1. Check for contamination
2. Check barrel purging
3. Inspect back ow ring for wear or cracks
4. Inspect feed screw for wear and tear
5. Inspect screw / barrel for tolerances
6. Verify heater operation
7. Verify thermocouple operation
20-21TROUBLESHOOTING
Hot Runner User Manual
© 2020 Mold-Masters (2007) Limited. All Rights Reserved.
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