Improvement in the injection moulding method for producing moulded plastic parts

摘要

To produce by the injection moulding method a large-sized and quite heavy part (1) of plastic material, the improved method according to the invention provides for localized zones to be created in which the thermal conductance of the part (1) is higher in surface impressions (10) in correspondence of the ejectors provided in the mould for the removal of the same part after it has been moulded. In a preferred embodiment, the outer surface of the part (1) has, in correspondence of the surface impressions (10), clusters of closed-bottom pits (13) formed by grids of mini-ribs (11) and (12) arranged perpendicularly with respect to each other. The thickness of the part changes from a maximum value (S1) at the periphery of the cavity to a minimum value (S2) in correspondence of the bottom of a substantial part of said pits (13).