Gate stringing or drooling

Gate stringing or drooling is caused by delayed freeze-off of melt in the gate. See Table 11.4 for some of the causes of stringing or drooling. 

Excessive heating of gate zone Check/renew nozzle thermocouple. Reduce manifold and nozzle temperature. Increase cooling of gate zone. Check gate size and geometry, change nozzle type or end (for amorphous plastics). 

Inadequate cooling time Extend cooling time. Use HR decompression to reduce residual melt pressure in HR. 

Shut-off nozzle pin does not close fully Proceed as in Table 11.2. 

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A certain amount of experience is required to avoid gate stringing or drooling of some plastics from the nozzle. 

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