Chemically-bonded sand - Full mould process

Chemically-bonded sand - Full mould process 

The Lost Foam process with chemically-bonded sand, in this case also called the full mould process , is mostly used for producing middle or large sized castings, in single production or in small batch series. 

The patterns are made from low density expanded materials, such as white, foamed polyst5rene, with a density of 16 to 20 g/dm  

These materials are cut out as various parts, which are then assembled and stuck together with hot melt glue, thus creating the final shape of the casting, also taking into consideration any possible shrinkage of the metal. 

The assembled pattern, with its gating and feeding system, has to be coated, mostly with a water-based coating system, and thoroughly dried before being embedded in the sand. The binding process of the sand has to be specially selected in order to avoid any moisture pick-up by the pattern before pouring. 

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Full mould process moulding technique using a foam model in chemically bonded sand, in which the model is lost upon pouring, generally used only for large castings... 

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