Mould Fouling, Cleaning and Management

The well-run factory should plan to minimise the problem of mould fouling in the following ways  

Trials are therefore an essential precursor to selection of the cleaning method. Dry blasting with fine glass beads produces a polished surface with minimal environmental impact. However, care needs to be taken with injection gates, vacuum ports and sprues, since they can become easily blocked or not be cleaned at all  

All abrasive cleaning processes may significantly change mould dimensions over a period of repeated cleaning cycles. For this reason it is imperative that regular dimensional checks are made and recorded for each mould. 

A relatively recent method is the use of solid carbon dioxide (dry ice). This is used in rice grain form or as granules shaved from solid blocks. These particles are applied 

Once the mould has been cleaned it becomes very susceptible to corrosion. Some factories overcome this problem by oiling the mould surfaces. This in itself gives rise to problems when the mould is needed for production. The best solution is to immediately apply a coating of a semi-permanent silicone resin release agent followed by a short bake cycle. This gives a mould that is immediately ready to produce first class mouldings. 

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