Cooling and counter-pressure method for producing plastic parts by injection

Cooling and counterpressure procedure for manufacturing plastic parts by the injection process, using a cavity (10, 10′) provided between a fixed part (1) of a mould and a mobile part (2) of the same mould, with plastic material being injected into the said cavity once it has been closed, and the said cavity having an auxiliary intake (4) for gas to circulate through its interior through a porous material (3) fitted in the moulds, which is characterised in that the gas to be introduced into the cavity (10, 10′) is at a low temperature, of between −196° C. and 50° C., and circulates through the said cavity during the cooling phase of the plastic material and over one of the sides of the material, in that the gas to be introduced and circulate through the cavity is at a pressure of between 5 and 100 bar.