
20.6.20 Weld Lines
The finished product has lines where two flow fronts meet and have not
fused, creating the possibility of weak areas and stress fractures.
Probable Cause:
1. Molding Machine
• Low injection speed
• Low injection pressure
• Short injection time forward
2. Mold
• Low mold temperature
• Poor venting
•
Back flow valve / check ring malfunctioning
• Gates too far apart
• Redesign part
3. Material
• Cold melt
• Material wrong grade for application
Solution (in sequence):
1. Increase injection pressure
2. Increase injection holding time
3. Increase injection speed
4. Increase cylinder temperature
5. Increase mold temperature
6. Check for venting
7.
Provide an overflow well adjacent to the weld area
8. Modify the gate location
9. Decrease gate land length
20-24
© 2020 Mold-Masters (2007) Limited. All Rights Reserved.
TROUBLESHOOTING
Hot Runner User Manual
Summary of Contents for Hot Runner
Page 1: ...Hot Runner User Manual Hot Runner User Manual version 31 Original Instructions...
Page 2: ......
Page 95: ......
Page 318: ......