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Orthogonal weaving for complex shape preformsOrthogonal weaving for complex shape preforms description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070175535, Orthogonal weaving for complex shape preforms. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0002] The present invention relates generally to composite preforms and methods for making composite preforms. BACKGROUND OF THE INVENTION [0003] In a gas turbine engine, air is pressurized in a compressor and mixed with fuel in a combustor and ignited for generating hot combustion gasses which flow downstream through several turbine stages. A turbine stage includes stationary turbine vanes extending radially between inner and outer castings. The vanes are hollow with openings that mate to openings within the castings. The vanes have airfoil configurations for guiding the combustion gasses between corresponding turbine rotor blades disposed downstream of the vanes. The blades are mounted to the perimeter of a rotor disk that rotates during operation for providing power to turn the compressor or fan during operation. Since the turbine vanes are heated during operation by the hot combustion gasses, which flow thereover, cooling air bled from the compressor, is channeled inside the vanes for cooling thereof. [0004] In order to increase the efficiency and the performance of gas turbine engines so as to provide increased thrust-to-weight ratios, lower emissions and improved specific fuel consumption, engine turbines are tasked to operate at higher temperatures. As the higher temperatures reach and surpass the limits of the material comprising the components in the hot section of the engine and in particular the turbine section of the engine, new materials must be developed. [0005] As the engine operating temperatures have increased, new methods of cooling the high temperature alloys comprising the combustors and the turbine airfoils have been developed. For example, ceramic thermal barrier coatings (TBCs) have been applied to the surfaces of components in the stream of the hot effluent gases of combustion to reduce the heat transfer rate and to provide thermal protection to the underlying metal and allow the component to withstand higher temperatures. These improvements helped to reduce the peak temperatures and thermal gradients. Simultaneously, ceramic matrix composites were developed as substitutes for the high temperature alloys. The ceramic matrix composites (CMCs) in many cases provided an improved temperature and density advantage over the metals, making them the material of choice when higher operating temperatures were desired. [0006] A number of techniques have been used to manufacture turbine engine components. One such technique includes manufacturing turbine blades from CMCs. One method of manufacturing CMC components, set forth in U.S. Pat. Nos. 5,015,540; 5,330,854; and 5,336,350; incorporated herein by reference in their entirety and assigned to the assignee of the present invention, relates to the production of silicon carbide matrix composites containing fibrous material that is infiltrated with molten silicon, herein referred to as the Silcomp process. The fibers generally have diameters of about 140 micrometers or greater, which prevent intricate, complex shapes, such as turbine blade components, from being manufactured by the Silcomp process. [0007] Another technique of manufacturing CMC turbine blades is the method known as the slurry cast melt infiltration (MI) process. A technical description of such a slurry cast MI method is described in detail in U.S. Pat. No. 6,280,550 B1, which is assigned to the Assignee of the present invention and which is incorporated herein by reference. In one method of manufacturing using the slurry cast MI method, CMCs are produced by initially providing plies of balanced two-dimensional (2D) woven cloth comprising silicon carbide (SiC)-containing fibers, having two weave directions at substantially 90.degree. angles to each other, with substantially the same number of fibers running in both directions of the weave. The use of two dimensional plies prevents intricate, complex shapes, such as turbine blade components, from being manufactured. [0008] One disadvantage of existing methods for production of CMC preforms is that the fibers that provide advantageous structural properties to a composite are not positioned and interlocked or interwoven to provide an optimal fiber architecture. Conventional methods of three-dimensional composite performing typically involve fabricating woven, or braided shapes that do not provide the desired complex preform shapes. What is needed is a method of weaving a three-dimensional composite preform that provides a tailored fiber architecture, which may be, assembled "near-net-shape". SUMMARY OF THE INVENTION [0009] Improvements in manufacturing technology and materials are the keys to increased performance and reduced costs for many articles. As an example, continuing and often interrelated improvements in processes and materials have resulted in major increases in the performance of aircraft gas turbine engines, such as the improvements of the present invention. The present invention is a novel method for manufacturing a turbine engine component made from a ceramic matrix composite (CMC) by weaving a three-dimensional composite preform that provides a tailored fiber architecture that may be assembled near-net-shape. A near-net-shape is a shape for a composite preform that, after weaving, requires little or no trimming prior to final fabrication of the composite. The present invention produces a component tailored to an intricate, complex shape having the advantage of a fine unit cell size inside the weave, wherein the resultant composite has superior mechanical properties and erosion resistance. [0010] The method of the present invention is particularly suitable for fabrication of turbine airfoil components for gas turbine engines. In particular, the method of the present invention is suitable for the fabrication of stationary turbine vanes for use in gas turbine engines. The method of the present invention is particularly suitable for composites having complex and/or intricate shapes, such as stationary turbine vanes, because the method allows fabrication of preforms of a complex and/or intricate shape that does not require trimming (i.e., near-net-shape) prior to final fabrication into the composite. [0011] The present invention provides a method of weaving a preform that includes positioning a predetermined number of warp pins on a base. The warp pins on the base are positioned to form a path substantially forming the outline of a desired preform shape. A predetermined number of dummy pins are positioned on the base, outlining the path formed by the warp pins. The dummy pin's help facilitate placement of the weft tow and stitcher tow by providing support for the tows along the path formed by the warp pins. The method further includes positioning a first predetermined number of weft tows adjacent the warp pins to form a general outline of the desired preform shape. A predetermined number of stitcher tows are positioned adjacent the warp and dummy pins. A predetermined number of stitcher tows are positioned adjacent and substantially perpendicular to the first predetermined number of weft tows. The warp pins and the dummy pins are advanced through the base to maintain a length of pin sufficient to place the weft and stitcher tows. A second predetermined number of weft tows are positioned adjacent the warp pins in the path formed by the warp pins, in a direction opposite the direction of the first predetermined number of weft tows. The second predetermined number of weft tows are laid upon the previously placed weft tows and stitcher tows. A second predetermined number of stitcher tows are positioned adjacent and substantially perpendicular to the second predetermined number of weft tows. The method is repeated in order to build a thickness of weft tows and stitcher tows. The plurality of weft tows and stitcher tows placed adjacent the warp pins and dummy pins form the general outline of the desired preform shape having a build dimension perpendicular to the weft tows and stitcher tows. When a predetermined thickness for the build dimension is reached, the warp and dummy pins are removed and the warp pins are replaced by warp tows. The resultant preform is near-net-shape having an interlocked and interwoven fiber architecture. [0012] Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0013] FIG. 1 is a sectional view of a hollow turbine for a gas turbine engine vane, illustrating the geometry of the vane along a radial axis of the engine. [0014] FIG. 2 is a perspective view of the orthogonal stitch-weave pattern of the present invention. [0015] FIG. 3 is a flow chart illustrating an exemplary method in accordance with the present invention. [0016] FIG. 4 is a sectional view illustrating an initial step of creating the stitch-weave of FIG. 2. [0017] FIG. 5 is a sectional view illustrating the arrangement of FIG. 4, with a further step of creating the stitch-weave of FIG. 2. [0018] FIG. 6 is a sectional view illustrating the arrangement of FIG. 5, with a further step of creating the stitch-weave of FIG. 2. [0019] FIG. 7 is a sectional view illustrating the arrangement of FIG. 6, with a further step of creating the stitch-weave of FIG. 2. [0020] FIG. 8 is a variation of the stitch-weave method shown in FIGS. 4 through 7. [0021] FIG. 9 is a variation of the stitch-weave shown in FIG. 8, illustrating an exemplary pattern used to create joints in complex shapes, in accordance with the present invention. Continue reading about Orthogonal weaving for complex shape preforms... Full patent description for Orthogonal weaving for complex shape preforms Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Orthogonal weaving for complex shape preforms patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Orthogonal weaving for complex shape preforms or other areas of interest. ### Previous Patent Application: Single layer papermakers fabric Next Patent Application: Three-dimensional complex coil Industry Class: Textiles: weaving ### FreshPatents.com Support Thank you for viewing the Orthogonal weaving for complex shape preforms patent info. 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