Device for injection moulding elastomers - includes injection piston and exhaust device to remove trapped air in piston cylinder

摘要

An injection moulding devide includes an injection unit comprising a cylinder contg. melt and a piston moveable in the cylinder. The injection unit is supported pref. by an elastomeric mounting above an upper plate having perforations which are alignment with mould cavities in a mould plate beneath the upper plate. As the piston is depressed the melt is forced through the perforations into the mould cavities. An exhaust device in the injection unit to remove gas (e.g. air) trapped in the cylinder as the piston is depressed. The devide is used for moulding elastomeric materials partic. rubber mixts. which are subsequently vulcanised. No air is trapped in the moulded article thereby producing a better quality article and preventing possible damage during vulcanisation.