Method and apparatus for moulding a fluid settable material

A method of moulding a plastic resin material, comprising the steps of:

• providing male and female mould halves and clamping said mould halves together,
• pulling a vacuum in a mould cavity defined by said male and female mould halves and sealed from the atmosphere by sealing means, by withdrawing air therefrom through at least one vacuum outlet leading via an isolation valve to a vacuum source, the mould halves being shaped such that a pinch line located radially inwardly of said sealing means is formed, said pinch line defining the periphery of a moulded product,
• injecting a plastic resin material into the thus evacuated mould cavity while maintaining communication with said vacuum source until the mould cavity is wholly filled by the plastic resin material,
• closing the said isolation valve between the vacuum outlet through which the air from the mould cavity is drawn and the vacuum source,
• injecting a small additional quantity of plastic resin material under pressure into the mould cavity,
• closing the inlet through which the fluid material is introduced into the mould cavity and
• allowing the plastic resin material to solidify.

Resin moulding apparatus for moulding plastic resin, comprising:

• first and second mould halves which can be brought together to define therebetween a mould cavity,
• first and second flange means projecting from said first and second mould halves respectively, around the periphery thereof,
• sealing means interposable between said first and second flange means of said mould halves for compression therebetween as said mould halves are brought together to close said mould cavity,
• clamp means engageable on said first and second flange means whereby to hold said first and second mould halves together to define said mould cavity and compress said sealing means between said first and second flange means,
• said clamp means clamping said mould halves together to maintain said mould cavity when resin is injected into said mould cavity under pressure,
• means defining at least one vacuum outlet from one of said first and second mould halves leading via an isolation valve to a vacuum source,
• means defining an inlet in at least one of said mould halves for the introduction of plastic resin into said mould cavity under pressure, and stop means on said mould halves for defining a line of closest approach of said mould halves on closure of said mould cavity, said stop means forming a pinch line located radially inwardly of said sealing means so as to define the periphery of a moulded product.