HR in stack moulds

The main element in each stack mould is the central plate containing the HR manifold and nozzles and the cavities. One difficult problem which is crucial to the design of the HR system is the way the melt is to be fed to the manifold. 

However, angled injection moulding machines, and especially large ones, make up only a tiny fraction of the injection machines in use. 

For design reasons it is difficult to use shut-off nozzles in stack moulds. Problems arise from the installation in the moulds of cylinders, which by nature are of substantial height. 

Serious problems are encountered in the design of stack moulds with two cavities (1+1), since in this instance it is not possible to use a central melt feed to the manifold via a sprue bushing. It is then necessary to design a system that delivers the melt from the side of the manifold. 

1 -nozzle 2 - flat, cavity, working as an insulation between nozzles 

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