Molds & Tooling
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PA6 Short Shot Venting Improvement
Problem Phenomenon
The end of thin-wall PA6 products is always underfilled, and raising pressure instead causes burnt
Cause Analysis
Poor venting at the cavity end compresses air to form back pressure that blocks filling, forced pressure increase adiabatically heats the trapped air to cause burnt, and pressure and venting form a vicious circle; during on-site troubleshooting, verify item by item according to this mechanism, avoiding blind machine adjustment based only on experience
Solution
Open vent grooves 0.02-0.03mm deep at the filling end and the weld line; use insert and ejector pin gaps to assist venting; reduce injection speed to give air time to escape
Key Takeaway
When short shot is accompanied by burnt, check venting first; venting improvement is more fundamental than pressure increase; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence; include this case in the defect archive as a troubleshooting reference for similar problems in the future
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