A process for preparing non-planar thermoplastic fiber reinforced composites utilizes drapeable thermoplastic impregnated fiber reinforced prepregs in a pressure thermoforming process employing but one diaphragm. The single diaphragm when initially used is flat, but becomes deformed, following its first use, to the shape of the finished part. The diaphragm thus deformed may be repeatedly used as it will still fit over the prepreg layup.
Thermoplastic elastomer film vacuum bags are provided which readily conform to the surface contour of the workpiece at low pressures without failure. The thermoplastic elastomer film can be made into thin films which are able to withstand higher pressures and temperatures than the prior art nylon films. The films can also withstand the presence of epoxide and phenolic resins during pressure and cure without degradation. Preferred thermoplastic elastomers are block copolymers such as Hytrel. The films are pliable and can be used with minimal or no pleating.
A process for fabricating manufactured articles from fiberglass reinforced thermoplastic sheets, which consists of forming said plates while they are heated at their melting point and coupled with a barrier film, by either blow-moulding or thermoforming.
A system and method for reducing the occurrence of undesirable deformations (e.g., wrinkling) in a reinforced thermoformable workpiece. The reduction in undesirable deformations is achieved by increasing the buckling resistance of the workpiece by employing a supplemental reinforcing structure. The reinforcement, in combination with a pair of shaping diaphragms, increase the effective buckling resistance applied to the workpiece during the fabrication of a composite product. The method includes forming a workpiece from a plurality of layers of a thermoformable material, and applying to at least one side of the material an external reinforcing structure to form a reinforced workpiece having a top side and a bottom side. At least one of the top or bottom sides of the reinforced workpiece is placed in contact vith a diaphragm, thus forming a shaping assembly. The shaping assembly is then urged into contact with a shaping surface of a work tool to form a composite product, having a shape complementary to the shape of the tool. The composite product is then removed from the tool.
A polymer composite reed for a reed valve is provided, wherein the reed has improved mechanical properties as a result of its construction and is highly resistant to chemical and thermal attack. The improved mechanical properties of the reed are primarily due to the reed being reinforced with two plies of fabric having a harness satin weave, which provides the reed with a flexural modulus that is substantially greater in one direction of the reed. The chemical and thermal properties are primarily due to the semicrystalline thermoplastic material from which the reed is formed. In addition, the thermoplastic material enhances the fracture toughness of the reed to improve the durability of the reed. As a result, the reed is highly suitable for applications requiring long life under high speed, cyclic loading, such as that found in two-stroke and four-stroke internal combustion engines for the automobile industry.
A method of fabricating a preform for use in a resin transfer molding process. The method includes the steps of locating a transport member on a mandrel. A dry fiber layer is filament wound about the mandrel over the transport member. A tackifier is applied to the dry fiber layer at least in the area of the transport member. The filament wound dry fiber layer is cut about the transport member to provide a preform thereon. The preform is transported to a resin transfer mold by use of the transport member. The preform then is resin transfer molded in the mold.
