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Type of Defect: |
Brittle Disk |
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Description: |
Brittle Disk |
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Observation Method: |
Visible under polarized light |
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Recommendation Upon Observation: |
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Other Evaluation Method: |
Internal stress test using the solvent method |
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Cause |
Countermeasure |
Brittle breakage of disc by rough gate surface, possibly during punching or ejection, Worn-out punch
caused by poor center hole quality. |
see Rough Center Hole |
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Insufficient molding condition causing internal stress |
Adjust cylinder temperature (too low) |
| Insufficient molding condition causing internal stress |
Adjust holding pressure (too high) |
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Insufficient molding condition causing internal stress |
Adjust injection speed (too slow) |
| Insufficient molding condition causing internal stress |
Adjust mold temperature, too low |
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Insufficient molding condition causing internal stress |
Adjust nozzle temperature, too low |
| Material degradation |
Adjust cylinder temperature (too high) |
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Material degradation |
Adjust drying condition (usuallly temperature is too low, or time span is too short) |
| Material degradation |
Adjust nozzle temperature (too high) |
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Material degradation |
Check cylinder temperature equipment |
| Material degradation |
Check material's mechanical property |
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Material degradation |
Check the nozzle temperature controller |
| Material degradation |
Use proper material handling procedure |
