Patent ID: 6939500

Claim:
A method of molding a sealing surface on a molded part and the part is molded in separable first and second pat-table mold halves that mate and meet when closed at a major parting line plane, the mold halves each having a mold half cavity, the half cavities of the mold halves together defining a complete mold cavity having a molding surface complemental to the exterior contour of the part to be molded therein when the mold halves are closed together, said method comprising the steps of: (a) providing respectively in said first and second mold halves first and second mold inserts that each have a sub-insert flash trimming component each defining a cooperative mold half cavity, said trim half cavities together defining a complete molding surface shaped to encompass and define upon mold closure that portion of the complete mold cavity molding surface that is to mold form said sealing surface when said mold inserts are closed together to define a minor parting line plane therebetween, (b) movably supporting said sub-inserts in said associated inserts mold half for motion such that the minor parting line plane of said mold sub-inserts is orientable by such motion through a given range of travel including a position flush with the mold major parting line plane, (c) closing the mold halves together. (d) positioning said sub-inserts at a starting position such that the minor parting line plane is positioned at a given orientation relative to the flush planes position thereof, (e) then filling the complete mold cavity with molding material in a liquid state, (f) allowing the liquid molding material to harden at least to a self-sustaining solidification strength at least in the part sealing surface zone adjacent the mold-sub-inserts cavity-defining surfaces, (g) then moving the sub-inserts as a unit relative to the mold halves to thereby shift the minor parting line plane of the sub-inserts to thereby move, and thereby trim, any parting line flash resident between the sub-inserts to, a second predetermined position offset from the starting position whereby such sub-insert parting line flash that might otherwise remain resident on the sealing surface is substantially removed from its residence position on such surface at the starting position of said sub-inserts, (h) then moving the sub-inserts to their flush planes position to thereby bring the minor and major parting lines flush with one another, (i) then opening the mold halves to remove the completed molded part.