METHOD OF MANUFACTURE OF HOLDER FRONT PARTS BY INJECTION MOULDING AND TRANSFER MOULD Russian patent published in 1995 - IPC

FIELD: processing of polymeric materials. SUBSTANCE: method includes filling of moulding core of transfer mould with heated plastic through the sprue channel, cooling, ejection and subsequent machining of cured part, in which before injection of heated plastic into the sprue channel, having a trapezoidal shape, fastening hinge members are inserted in the spaces formed on the sides of the moulding core, part cooling process lasts 4 to 6 s. The transfer mould is a matrix located on which are the cores moulding the facet groove spews, top force, ejector sprues, moulding the side cores for the fastening hinge members, spring-loaded pushers with a spring, screws for fastening the facet core with a strip, trapezoidal sprue channel, hinge fastening members; the core moulding the facet groove spew has around the edges interrupted longitudinal prominent recesses, whose depth equals h=H/2 of the depth of the moulding core groove spew, nose-stop link and surfaces for conjugation to lugs. Maximum width of fenestrations in the vertical plane L₃ = 3B with maximum length in the horizontal plane L₂= 1.7 L₃, and the width of the surfaces for conjugation to lugs equals L₄= L₃/6, and the overall length of the holder front part equals L₁. When the offered method is used, the time of machining of finished part is decreased due to intermelting of hinge fastening members before casting, shrinkage of material after cooling decreases due to the presence of hinge components in the casting, which saves the material; trapezoidal shape of the sprue channel reduces the area pressure at part moulding, which in total with the time of cooling within 4 to 6 s makes the finished part more durable and strong in service. EFFECT: simplified process of manufacture and enhanced quality of products. 2 cl, 5 dwg