Molds & Tooling
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PA12 Burnt and Trapped Air
Problem Phenomenon
【Problem phenomenon】PA12 products were burnt and blackened at the ends and rib positions, accompanied by odor
Cause Analysis
Poor venting causes trapped air to be adiabatically compressed and heated, burning the melt, which is more likely when melt temperature is high; burnt locations are also accompanied by material degradation and strength loss; during on-site troubleshooting, verify item by item according to this mechanism, and avoid blindly adjusting the machine based only on experience
Solution
Add vent holes and grooves to unblock the trapped air path; lower barrel temperature and injection speed; enlarge the gate to reduce filling shear heat; after adjustment, take consecutive samples to verify the effect, and resume mass production only after confirming stability
Key Takeaway
For burnt parts, first unblock venting, then lower temperature and speed; a too-small gate is also an accomplice; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence; include this case in the defect archive as a reference for troubleshooting similar problems in the future
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