Processing Machinery
7 visualizaciones
PPS Black Specks from Residual Material
Fenómeno del problema
Black specks and discolored streaks appear on the parts; the situation improves briefly after barrel cleaning but recurs
Análisis de la causa
After PPS shutdown, material remaining in the barrel above 280°C for a long time degrades and carbonizes; upon restart, carbonized material is released periodically; during shutdown, the barrel temperature should be lowered below 280°C for heat preservation
Solución
①During shutdown, lower the barrel temperature below 280°C for heat preservation; ②For long shutdowns, purge by replacement with HDPE; ③Upon restart, purge the first few shots; after adjustment, take continuous samples to verify the effect, and resume mass production only after confirming stability
Conclusión clave
Ninety percent of PPS black specks trace back to shutdown retention; the 280°C heat-preservation line and HDPE replacement are standard procedures; after confirming effectiveness, fix the parameters and practices into the work instruction to prevent recurrence
¿Le ha resultado útil?
0 personas encontraron esto útil
¡Gracias por sus comentarios!