Plural ejector pins are made to project before a molten resin containing reinforcing fibers is injected into an inside of a cavity through pin point gates in a web forming portion in the inside of the cavity and at positions outside the pin point gates in a radial direction. The ejector pins are retracted from the inside of the cavity after a flow of the molten resin containing reinforcing fibers injected into the inside of the cavity through the pin point gates impinges on the ejector pins and is divided and before a tooth portion forming portion in the inside of the cavity is filled with the molten resin containing reinforcing fibers. Accordingly, weld lines which extend along the radial direction are formed at positions outside the ejector pins in the radial direction, and the molten resin is filled in portions formed after the ejector pins are retracted.

A method for making structural foam parts having continuous aligned fibers includes placing an assemblage of fiber-bundle-based preforms in an injection mold, creating a melt flow of resin and, optionally, short, loose fiber, and adding foaming agent to the melt flow. When the foaming agent/melt flow mixture is introduced into the injection mold, the foaming agent foams. The assemblage is structured and positioned so that fibers therefrom adopt a desired alignment and position in the final part. Structural foam fills the remainder of the volume of the part.

The present invention is relates to a fiber reinforced resin screw 10, 20 shaped using a resin composition containing reinforcing fiber in a resin. A pitch of threads has a length of 1.5 to 2 times of a standard pitch corresponding to an outer diameter of the threads prescribed in standards of a metric coarse screw, a unified coarse screw and a unified fine screw. An average fiber length of the reinforcing fiber is 1 to ⅓ times of the pitch of the threads in the fiber reinforced resin screw. A content rate of the reinforcing fiber is in a range of 20 to 80%. In this way, the fiber reinforced resin screw to have improved is provided in the strength of the thread.

A fiber reinforced thermoplastic resin molded article includes (A) carbon fibers, (B) graphite and (C) a thermoplastic resin, wherein the carbon fibers (A), the graphite (B) and the thermoplastic resin (C) are contained in amounts of 1 to 30 parts by weight, 1 to 40 parts by weight and 30 to 98 parts by weight, respectively, relative to 100 parts by weight, of the carbon fibers (A), the graphite (B) and the thermoplastic resin (C), the weight average fiber length of the carbon fibers (A) is 0.3 to 3 mm and the specific gravity of the molded article is 1.1 to 1.9 g/cm.sup.3. The fiber reinforced thermoplastic resin molded article has excellent bending strength and heat conductivity.

Plural ejector pins are made to project before a molten resin containing reinforcing fibers is injected into an inside of a cavity through pin point gates in a web forming portion in the inside of the cavity and at positions outside the pin point gates in a radial direction. The ejector pins are retracted from the inside of the cavity after a flow of the molten resin containing reinforcing fibers injected into the inside of the cavity through the pin point gates impinges on the ejector pins and is divided and before a tooth portion forming portion in the inside of the cavity is filled with the molten resin containing reinforcing fibers. Accordingly, weld lines which extend along the radial direction are formed at positions outside the ejector pins in the radial direction, and the molten resin is filled in portions formed after the ejector pins are retracted.

A process for resin transfer molding (RTM) with staggered injection of a resin is provided that injects resin into a plurality of injection ports of a mold. The temperature and pressure applied to the mold are controlled during injection to limit promote rapid filling of the mold cavity. The injection ports are activated for injecting the resin in any order of individually, in groups, or pairings. Fibers are readily added to the mold separately or within the resin. Cycle times of from 1 to 5 minutes are provided for the process.

A stator for use in a positive displacement motor or a progressing cavity pump. The stator comprises an elastomer mix preferably including rubber and a fiber reinforcement. The fiber reinforcement includes a plurality of fibers. The elastomer mix is formed into a stator via an injection molding process. The injection molding process includes a shear flow step in which shear flow is induced in the elastomer mix while the elastomer mix is in an uncured state. The shear flow modifies the orientation of the fibers into an advantageous modified fiber orientation. Shear flow is induced preferably via differential rotation of injection mold assembly elements during the injection molding process. Methods of manufacturing the stator are also disclosed.

The present invention relates to manufactured articles consisting of the coupling of at least two polyamide-based parts, one of which consists of a polyamide matrix, preferably loaded with a dispersed filler, and the other consists of a polyamide matrix reinforced with fibres in their turn made of polyamide. The invention also relates to a process for the production of these manufactured articles. The manufactured articles of the invention have high mechanical strength but, unlike similar manufactured articles, they are made of a single polymer.

In the present invention, it is possible to reduce the occurrence of a local deformation in a plate material during solidification and shrinkage of an injection molding material. The composite material injection molding method includes an injection step of injecting an injection molding material containing reinforcing fibers onto one surface of a plate material; and a molding step of solidifying the injection molding material to mold a frame part so as to surround the outer periphery of the plate material and to mold a rib so as to define an inner peripheral-side space on the inner peripheral side of the frame part. In the injection step, the injection molding material is injected so that a weld part at which the injection molding material converges is formed in a region not overlapping the plate material of the frame part.

A method for making structural foam parts having continuous aligned fibers includes placing an assemblage of fiber-bundle-based preforms in an injection mold, creating a melt flow of resin and, optionally, short, loose fiber, and adding foaming agent to the melt flow. When the foaming agent/melt flow mixture is introduced into the injection mold, the foaming agent foams. The assemblage is structured and positioned so that fibers therefrom adopt a desired alignment and position in the final part. Structural foam fills the remainder of the volume of the part.