Compression moulding apparatus and method for forming plastics objects

Abstract

A method comprises compression-moulding plastics to obtain objects (9) by mould means (2), said mould means (2) being provided with punch means (11; 111) and with die means (31, 32; 131, 132), said die means (31, 32; 131, 132) comprising a die body (31; 131) and a bottom element (32; 132) mutually cooperating to define a portion of a forming cavity, said moulding comprising reciprocally moving said die means (31, 32; 131, 132) and said punch means (11; 111), there being furthermore provided driving said bottom element (32; 132) independently of said punch means (11; 111) and of said die means (31, 32; 131, 132); an apparatus for compression-moulding plastics to obtain objects (9) comprises die means (3) provided with die-body means (31; 131) and with bottom-element means (32; 132) mutually cooperating to define a portion of forming cavity means, fluid-operating means (24) arranged to reciprocally move said bottom-element means (32; 132) and said die-body means (31; 131) and passage means arranged to convey said fluid-operating means, said passage means comprising throttle means (27).

Description

technical field [0001] The present invention generally relates to the compression molding of polymeric articles by pressure coupling a male die with a closed cavity die loaded with a dose of polymer which is first dispensed on the outside of the die and subsequently injected into the die. in the mold cavity. Background technique [0002] The forming die has a die having a lower portion adapted to shape the lower portion of the outer surface of the article, the inner surface of which is formed by a lower end portion and axially elongated side portions. [0003] The dose, substantially in a molten state and in a more or less viscous state, is dispensed to the outside through a dispensing outlet in a suitable position outside the cavity of the die, and is then injected into the inside of the die. [0004] During injection, the dose comes into contact with the side regions of the cavity of the die, preventing the dose from falling with difficulty or incorrectly or not at all in...

AI Technical Summary

Problems solved by technology

In this case, an operating step is performed in which the dose is only accommodated in the lower part of the die, and this lower part must be designed with a height and capacity sufficient to accommodate the dose adequately and, as described above, prevent the dose from protruding in an unacceptable manner into the outside of the die, and prevents the die from closing properly

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