20.6.5 Delaminating Parts
The nished product is separating into layers that can be peeled o; surface
layers are aking o. Insucient layer bonding as a result of high shear
stresses; non homogeneous material.
Probable Cause:
1. Molding Machine
• High injection speed
2. Mold
• Cold mold
• Gate has sharp corners
• Sharp corners causing shear heat
3. Material
• Physical contamination of raw material
• Chemical contamination of raw material
• Melt too hot / poor melt
• Incompatible color dye
• High percentage of recycled material
Solution (in sequence):
1. Increase melt temperature
2. Increase mold temperature
3. Decrease injection speed
4. Eliminate contamination
5. Adjust regrind ratio
6. Adjust or change resin moisture content
7. Purge system
8. Reduce sharp corners at gate
20-9TROUBLESHOOTING
Hot Runner User Manual
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