Shut-off nozzle leaves vestige

A vestige is left on the moulding when the nozzle pin fails to shut off the gate. A vestige may also occur if the pin is too hot and draws material out of the moulding. Some of the causes of this are shown in Table 11.2. 

Damaged gate Check pin length and if necessary shorten. Check concentricity of pin and gate and if necessary renew. 

Damaged seal in nozzle drive cylinder Renew. 

Inadequate pin contact with gate Increase gate zone cooling. Increase length of pin contact with gate. 

Inadequate oil/air pressure Carefully increase pressure (too great a force may damage gate). 

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