Abstract: The manufacture of a plastic material, particularly provided with fibers, is frequently carried out in an extruder (10). Various problems have arisen in this connection. For example, problems arise in working long or endless reinforcement fibers, for example rovings (27), into the plastic. On the one hand, the fibers are so badly broken up that they have only very small lengths. On the other hand, it has proved difficult to impregnate the fibers sufficiently. According to the invention, in order to feed in fibers, the plastic is moved in batches past a pre-plastifying worm (11). This is achieved by a secondary worm (18) located next to the pre-plastifying worm (11).

Abstract: A flexible glass fiber reinforcement material has microwave-sensitive or ultraviolet sensitive binder added and is formed into a desired shape. Selected electromagnetic energy (microwave or ultraviolet) is then applied to cure and rigidize the binder. A mold for shaping the reinforcement material comprises a mold cavity defined by microwave or ultraviolet transparent material divided into separate and separable mold parts and, for microwave applications, each part carries one half of a split microwave waveguide which directs microwave energy to cure the binder resin when the mold is closed. For ultraviolet applications, an ultraviolet source (or sources) is located in the mold. Energetic stitching of a reinforcement rib is performed by applying a binder resin to the rib at at least one location, placing that location into contact with a preform and curing the binder resin to bond the parts together.

Abstract: A process for manufacturing simple or complex reinforcement preforms for use in resin transfer molding (RTM), structural reaction injection molding (SRIM) or similar molding processes includes applying a thermosetting binder, which is sensitive to selected ultraviolet or microwave radiation, to planar woven or non-woven reinforcing materials, the binder-bearing reinforcing material being placed into a three-dimensional mold and pressed into a desired shape, cured in the mold by applying a corresponding selected ultraviolet or microwave energy thereto to cure and rigidize the binder and hold reinforcement material in the three-dimensional shape resulting in a rigid three-dimensional preform to be used in subsequent molding operations. Structural reinforcements, sub-assemblies and the like may be applied to the preform to enhance the final properties of the final composite structure.

Abstract: The method and apparatus for making a preform which is a rigid shaped item formed of glass fibers rigidly joined to each other where adjacent fibers touch. The interstices between the fibers are unfilled for the use of matrix resin to subsequently form a molded article. The preform is formed by shaping fibers into the preform shape, applying a binder to the fibers so that they are coated at the locations where they touch. The binder is sensitive or responds to the application of electromagnetic energy. In completing the preform after the application of the binder, the preform is subjected to electromagnetic energy so that the binder hardens to form a rigid preform. In one species form, the electromagnetic energy is applied in the form of microwave energy. The application of electromagnetic energy causes a reaction in the binder without requiring heating of the glass fibers so that the preforms can be rigidified rapidly and efficiently.

Abstract: A rigid three-dimensional preform is made by moving a plurality of webs of fibrous reinforcement material superposed and coplanar to a cutter, the webs being coated with an electromagnetic energy-curable binder and pressed together. Prior to cutting a blank in a two-dimensional development of the three-dimensional preform from the webs, the webs are tacked together at spaced local zones by locally curing the binder at those zones by locally applying the appropriate electromagnetic radiation (microwave, ultraviolet, electron) so that the webs travel as one to the cutter. After cutting of the blank, the blank is loaded into a mold to replicate the three-dimensional shape of the preform and the remainder of the binder is cured in the mold by the application of the appropriate electromagnetic radiation.

Abstract: A three-dimensional complex preform is made formed of various types of reinforcement fiberglass fibers with a binder at the interstices which rigidize the preform to the shape and form approximating the molded article, which can be handled and stored until a final mold is made filling the interstices with plastic and curing the plastic. Complex preforms require either specific reinforcements in the form of increased sections, specific reinforcement, or require modification or enlargement in size or increase in complexity by the attachment of one or more additional preforms. To modify an existing preform and obtain a desired shape and form, reinforcement members or additional preforms are attached by energetic stitching. Energetic stitching includes the application of an electromagnetic energy curable binder and the application of electromagnetic radiation to cure the binder.

Abstract: A rigid three-dimensional preform is made by moving a plurality of webs of fibrous reinforcement material superposed and coplanar to a cutter, the webs being coated with an electromagnetic energy-curable binder and pressed together. Prior to cutting a blank in a two-dimensional development of the three-dimensional preform from the webs, the webs are tacked together at spaced local zones by locally curing the binder at those zones by locally applying the appropriate electromagnetic radiation (microwave, ultraviolet, electron) so that the webs travel as one to the cutter. After cutting of the blank, the blank is loaded into a mold to replicate the three-dimensional shape of the preform and the remainder of the binder is cured in the mold by the application of the appropriate electromagnetic radiation.

Abstract: A directed fiber, directed energy process provides both a method and an apparatus for making structural preforms. Fibrous reinforcement material is chopped into short lengths of fiber and propelled toward a perforate mold part. During propulsion and/or after deposition on the perforate mold part the fibers are sprayed with an electromagnetic radiation-curable binder. The binder-carrying fibers are held on the perforate mold part by a flow of air in that the perforate mold part is rotatably mounted in a plenum which provides an air flow therethrough. Rotation of the perforate mold part and scanning action of the fiber and binder propelling mechanisms effects even and complete coverage of the perforate mold part. After a mat of the chopped fibers has been applied to the perforate mold part, a conforming second mold part closes the mold and presses the fibers to replicate the shape of the three-dimensional rigid preform.

Abstract: Glass fiber mats are made for subsequent use in preforming for an RTM or SRIM molding process, for example, such that the binder applied to the mat has two distinct curing stages. In the first stage, a partial cure is provided by visible light upon a free radical generation in response to a photoinitiator mixed in the binder in an exact ratio to give a predictable increase in viscosity to that of a semi-solid so that the fibers are sufficiently bound for subsequent handling, but not sufficient to complete a cure, while leaving a second stage ready for a final cure which is achieved by the use of a cationic-type second photoinitiator which is sensitive to ultraviolet light. During the second curing stage, the mat is formed into a three-dimensional shape of a desired end product and cured with ultraviolet radiation while still in the mold, to obtain a rigid three-dimensional preform structure.

Abstract: A rigid three-dimensional preform is made by moving a plurality of webs of fibrous reinforcement material superposed and coplanar to a cutter, the webs being coated with an electromagnetic energy-curable binder and pressed together. Prior to cutting a blank in a two-dimensional development of the three-dimensional preform from the webs, the webs are tacked together at spaced local zones by locally curing the binder at those zones by locally applying the appropriate electromagnetic radiation (microwave, ultraviolet, electron) so that the webs travel as one to the cutter. After cutting of the blank, the blank is loaded into a mold to replicate the three-dimensional shape of the preform and the remainder of the binder is cured in the mold by the application of the appropriate electromagnetic radiation.

Abstract: A directed fiber, directed energy process provides both a method and an apparatus for making structural preforms. Fibrous reinforcement material is chopped into short lengths of fiber and propelled toward a perforate mold part. During propulsion and/or after deposition on the perforate mold part the fibers are sprayed with an electromagnetic radiation-curable binder. The binder-carrying fibers are held on the perforate mold part by a flow of air in that the perforate mold part is rotatably mounted in a plenum which provides an air flow therethrough. Rotation of the perforate mold part and scanning action of the fiber and binder propelling mechanisms effects even and complete coverage of the perforate mold part. After a mat of the chopped fibers has been applied to the perforate mold part, a conforming second mold part closes the mold and presses the fibers to replicate the shape of the three-dimensional rigid perform.

Abstract: A mat of reinforcement material, such as glass fiber reinforcement material, is manufactured by forming a layer of continuous strand or chopped fibers on a conveyor belt and conveying the layer along a defined path. At a location downstream of the application of the layer, the layer of fibers is coated with a binder in the range of 2.0-10.0 weight percent, either a microwave-sensitive binder or an ultraviolet-sensitive, binder and the binder-coated layer is fed into a radiation tunnel which includes a compression stage and a curing stage. In this radiation tunnel, the binder-coated layer is compressed to a desired density-thickness ratio and cured, the compression and curing occurring in stages, and the resulting mat is taken from the conveyor belt and wound up for storage.

Abstract: A method and apparatus for linear and nonlinear control of a hydraulic press is provided with a feedback loop allowing the operation of a variable displacement pump to be selectively controlled with respect to either hydraulic pressure moving a piston in a cylinder, or the velocity of the piston. During controlled movement of the piston, a directional valve blocks a pump compensator so that the pump operates as a fixed displacement pump to provide fast response to feedback signals. Simultaneously, the directional valve connects a proportional pressure controller to a relief valve. During a period when the piston is maintained in fixed position, the directional valve is switched so that the proportional pressure controller now controls the pump compensator and the relief valve is blocked, so that energy consumption is substantially reduced.