COMPRESSION MOULDING APPARATUS AND METHOD FOR FORMING PLASTICS OBJECTS

摘要

The unit operates by coupling together under pressure a punch (11) and a die with its closed cavity loaded with a charge of polymer material, the charge being produced outside the die and then inserted into the die cavity. The unit comprises a mould having a lower die part arranged to form the lower part of the outer surface of the article, the inner surface (30a) of which comprises a lower end portion and an axially extending lateral portion. The lower die part (30) comprises a first constituent member (31) and a second constituent member (32) having inner surfaces (33, 34) which can be complementarily aligned to together define the inner surface (30a) of the lower die part (30); the inner surface (34) of the second constituent member (32) defines totally or to a large extend said lower end portion of the inner surface of the lower die part (30). The second constituent member (32) is movable relative to the first constituent member (31) between an upper position in which its inner surface (34) is in said position aligned with the inner surface (33) and a withdrawn positionin which its inner surface (34) lies spaced from the inner surface (33) in order to increase the volume of the cavity of the lower die part (30).