A method produces an injection molded part. A plastic material is injected into a cavity for forming the injection molded part. The plastic material in a flow line region of the cavity, where the plastic material from two directions coincides during an injection molding process, is at least partially removed from the cavity via at least two overflow points and, in so doing, is locally swirled or mixed between the overflow points.

A method of forming a vehicular instrument panel includes the steps: melting a first composite comprising carbon fibers and nylon resin; melting a second composite comprising glass fibers and nylon resin; injecting the melted composites into an instrument panel mold such that the carbon and glass fibers are each substantially concentrated within respective driver-side and passenger-side portions of the mold; and cooling the melted composites to form an instrument panel. The method may also include the step: forming a boundary region between the first and second melted composites in the mold such that the carbon and glass fibers in the mold are substantially mixed within the boundary region.

An injection molding mold 2 where a molten resin containing reinforcing fibers is injected from a gate 11 into a cavity 5 to join the molten resins containing the reinforcing fibers together in the cavity 5 to form a weld portion. The injection molding mold 2 includes a reinforcing fiber orientation change concave portion 20 formed at a position displaced from the weld portion. The reinforcing fiber orientation change concave portion 20 opens to the cavity 5. The reinforcing fiber orientation change concave portion 20 causes the molten resins containing the reinforcing fibers 25 in the cavity 5 to partially flow into the reinforcing fiber orientation change concave portion 20 to disturb directions of the reinforcing fibers at the weld portion. Consequently, the reinforcing fibers at the weld portion and near the weld portion in the cylindrical article 1 tangle, thus improving the strength at the weld portion in the cylindrical article 1.

A method produces an injection molded part. A plastic material is injected into a cavity for forming the injection molded part. The plastic material in a flow line region of the cavity, where the plastic material from two directions coincides during an injection molding process, is at least partially removed from the cavity via at least two overflow points and, in so doing, is locally swirled or mixed between the overflow points.

A production method for a resin-molded product includes preparing a mold frame including an accommodation portion accommodating the first resin member therein, a first flow path extending in a first direction, and a second flow path extending in a second direction intersecting the first direction and making the first flow path and the first resin member in the accommodation portion communicate with each other, injecting a molten resin forming the second resin member into the first flow path and causing the molten resin to flow from the first flow path to the second flow path, contacting the molten resin and the first resin member to form a welded portion between the molten resin and the first resin member, and cooling the molten resin to form the second resin member, wherein the welded portion is formed in the second flow path.