Method, for making mold with hook sprue for injection molding of high precision plastics oil seal rings, involves inserting tapering channel as hook sprue leading to mold cavity

摘要

To produce a mold for the injection molding of small plastics components, a tapering channel as a hook sprue is inserted into an injection mold, leading to a mold cavity. A solid mold piece (W) is produced by program-controlled spark erosion in a horn-shaped curved hollow sprue (H) with an end passage (40). A programmable erosion machine is at a swing pin holder (30) with a prepared electrode (20) through an accurate co-ordinate position at the side surface (F) of the mold piece, to form the passage at the same side surface. The axis of the pointed electrode is curved, and its other end is at the swing pin. The swing pin is at an adjustable slide in a fitting drilling, centrally at the machine center point (18), where the neutral electrode center line (16) is centered by a gap using end dimensions. At least one flushing drilling at the electrode constantly extracts removed material.