Purging to clear

By joeprocess
Published: April 15th, 2009

I know that I have asked this before and have tried everything that was suggested as far as different purge compounds, but I still haven't seen the results I would like to see.

Any other ideas on how to go from a white colored PC to a clear PC fairly quickly without too many cloudy parts.

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Hi, This depends also on the

Submitted by Gil on April 15, 2009 - 10:20am.

Hi,

This depends also on the mould that you have. Are you using any hot runner system. Usually with HRs it takes a bit more to preform the colour change.
Anyhow, the idea is to create as much shear as possible inside the barrel. So you can for example reduce the temperature of the heater bands and increase the injection speed. I usually make like this to preform colour change w/ PP for caps and stuffs like that, where typically you need a fast colour change.

If you are using a hot runner, after cleaning the barrel, you have to increase the temperatures of the heaters on the HR maintaining the low temperatures and fast injection speed (pay attention on the injection pressure and compare it with the max. injection pressure that your HR supports to avoid bad surprises).

Cheers,

Gil