Processing Machinery
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Shutdown Carbonization Failure of PEEK
Problem Phenomenon
When PEEK production resumes after a mid-run shutdown of more than 15 minutes, the first batch of products shows a concentrated outbreak of yellowing, black specks, and silver streaks, requiring multiple shots to return to normal.
Cause Analysis
During the shutdown, the PEEK in the barrel continuously thermally degrades above 380℃, the melt carbonizes, discolors, and generates gas; the longer the residence time, the thicker the degraded layer, and the degraded material is gradually mixed into the products after restarting.
Solution
①If a shutdown of more than 15 minutes is expected, immediately lower the barrel temperature to a safe range; ②For long shutdowns, displace and drain with a dedicated purging compound; ③Fully discharge material and extend purging shots before resuming production; ④Establish shutdown operation specifications.
Key Takeaway
The core of PEEK shutdown management is dual control of time and temperature; 15 minutes is the empirical red line; the cost of discharging material at shutdown is far lower than batch scrap caused by degraded material mixing in.
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