Processing Machinery
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PA66 material changeover and purging difficulty
Problem Phenomenon
After changing PA66 to other materials, black specks persist for a long time and cannot be cleaned.
Cause Analysis
Residual carbonized layer of PA66 at high temperature is firm; a dedicated purging process is needed; ordinary purging methods are difficult to remove it; during on-site troubleshooting, verify item by item according to this mechanism, and avoid blindly adjusting the machine based solely on experience.
Solution
①Lower temperature to 250℃ and use PC or PMMA type purging material to displace the carbide; ②then raise temperature and change to the target material; ③remove the screw for inspection if necessary; ④record the SOP.
Key Takeaway
PA66 material changeover='first use solvent-type material to pull out carbon': a dedicated purging process is standard; the carbonized layer of high-temperature nylon is stubborn, and purging must pay attention to method and temperature gradient.
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