Abstract:
An exemplary weaving method includes placing a first section of a fill fiber between warp fibers, forming a pick, moving a base to reposition the warp fibers, and placing a second section of the fill fiber between the warp fibers.

Description:
BACKGROUND 
     This disclosure relates generally to a woven structure and, more particularly, to weaving a structure that has varying contours. 
     Woven structures are known. Woven structures are made of multiple picks along the formation direction. In some traditional weaving techniques, the term “pick” describes one fill fiber that has been deposited and encapsulated by the entire array of warp fibers one row at a time. The term “pick” may apply to encapsulation of the fill fiber by one adjacent pair of warp fibers at a time. 
     Many components, such as ceramic matrix composite (CMC) or organic matrix composite (OMC) components used in a jet engine, use woven structures as preforms. The woven structure strengthens the component. During manufacturing of such components, the woven structure is placed in a mold as a precursor. A material is then injected into the remaining areas of the mold. The injected material or resin surrounds the woven structure within the mold. If the mold has varying contours, manipulating woven assemblies, which are relatively planar, into a shape suitable for placing into the mold is difficult. Existing techniques for such manipulation may weaken the woven structures. 
     SUMMARY 
     A weaving method according to an exemplary aspect of the present disclosure includes placing a first section of a fill fiber between warp fibers, forming a pick, moving a base to reposition the warp fibers, and placing a second section of the fill fiber between the warp fibers. 
     In a further non-limiting embodiment of the foregoing weaving method, the method may secure the warp fibers to the base. 
     In a further non-limiting embodiment of either of the foregoing weaving methods, the method may include adhesively securing the warp fibers to the base. 
     In a further non-limiting embodiment of any of the foregoing weaving methods, the method may include moving the warp fibers after placing the first section and before placing the second section. 
     In a further non-limiting embodiment of any of the foregoing weaving methods, the method may include crossing the warp fibers over the first section before placing the second section. 
     In a further non-limiting embodiment of any of the foregoing weaving methods, the method may include injecting a molding material around at least a portion of the pick. 
     In a further non-limiting embodiment of any of the foregoing weaving methods, the method may include placing using a wand, the base moveable relative to the wand. 
     In a further non-limiting embodiment of any of the foregoing weaving methods, the method may include forming another pick with the second section. 
     A weaving method according to another exemplary aspect of the present disclosure includes forming a first pick, repositioning warp fibers by moving warp fiber arms relative to a fill fiber wand, repositioning warp fibers by moving the base relative to the fill fiber wand, and forming a second pick. Each of the warp fibers extend from one of the warp fiber arms to the base. 
     In a further non-limiting embodiment of the foregoing weaving method, the base may be configured to move relative to the fill fiber wand in three dimensions during the repositioning. 
     In a further non-limiting embodiment of either of the foregoing weaving methods, the base may be configured to move relative to the fill fiber wand around three axes of rotation during the repositioning. 
     In a further non-limiting embodiment of any of the foregoing weaving methods, the warp fibers are adhesively secured to the base. 
     In a further non-limiting embodiment of any of the foregoing weaving methods, the method may include positioning a fill fiber using the fill fiber wand. 
     In a further non-limiting embodiment of any of the foregoing weaving methods, the method may include forming the first pick comprises entrapping a first portion of a fill fiber between warp fibers. 
     In a further non-limiting embodiment of any of the foregoing weaving methods, the method may include crossing the warp fibers over the first section before placing the second section. 
     A weaving assembly according to an exemplary aspect of the present disclosure includes, among other things, a wand configured to position a first portion of a fill fiber woven between warp fibers to provide a pick, and a base that is moveable relative to the wand to adjust the position of the warp fibers. 
     In a further non-limiting embodiment of the foregoing weaving assembly, warp fiber arms may be each configured to move a respective one the warp fibers to a position that entraps the first portion of the fill fiber. 
     In a further non-limiting embodiment of either of the foregoing weaving assemblies, the fill fiber may comprise at least one of a glass, graphite, polyethelene, aramid, ceramic, boron. 
     In a further non-limiting embodiment of any of the foregoing weaving assemblies, the pick may be a portion of the woven structure. 
     In a further non-limiting embodiment of any of the foregoing weaving assemblies, the woven structure may comprise a portion of a base of a composite component. 
    
    
     
       DESCRIPTION OF THE FIGURES 
       The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows: 
         FIG. 1  shows a schematic view of an example weaving assembly. 
         FIG. 2  shows a perspective view of a portion of the  FIG. 1  weaving assembly having a partially finished woven structure. 
         FIG. 3  shows a section view at line  3 - 3  in  FIG. 2 . 
         FIG. 4  shows a close-up view of an Area 4 of the woven structure during the weaving. 
         FIG. 5  shows a close-up view of an Area 5 of the woven structure during the weaving. 
         FIG. 6  shows an example finished woven structure. 
         FIG. 7  shows a perspective close-up view of a base of the  FIG. 1  weaving assembly, showing discrete warp fibers attached, prior to weaving the structure of  FIG. 2 . 
         FIG. 8  shows a side view of a base of the  FIG. 1  weaving assembly when weaving the structure of  FIG. 2 . 
         FIG. 9A  shows a partial view an area of the woven structure during an initial weaving step. 
         FIG. 9B  shows a partial view an area of the woven structure during a weaving step later than what is shown in  FIG. 9A . 
         FIG. 9C  shows a partial view an area of the woven structure during a weaving step later than what is shown in  FIG. 9B . 
         FIG. 10  shows a close-up view of warp handling arms of the  FIG. 1  weaving assembly when weaving the structure of  FIG. 2 . 
         FIG. 11  shows a close-up view of a woven structure having multiple layers. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an example weaving assembly  10  is used to weave a woven structure  14 . The weaving assembly  10  includes a wand  18 , a base  22 , and a plurality of warp fiber arms  26 . 
     When weaving the woven structure  14 , the wand  18  positions a fill fiber  30  between warp fibers  42 . The fill fiber  30  extends from a spool  34  through a bore  38  in the wand  18 . The wand  18 , in this example, is a hollow tube. A fill fiber feed device may be included to meter the feed rate of the fill fiber with respect to the instantaneous relative velocity of the wand tip to the textile being created. The warp fibers  42  are manipulated by warp fiber arms  26 . 
     The assembly  10  includes a positional controller  46  associated with the wand  18 , a positional controller  50  associated with the warp fiber arms  26 , and a positional controller  54  associated with the base  22 . The positional controller  46  is able to move the wand  18  relative to the warp fiber arms  26  and the base  22 . The positional controller  50  is able to move the warp fiber arms  26  relative to the wand  18  and the base  22 . The positional controller  54  is able to move the base  22  relative to the wand  18  and the warp fiber arms  26 . The positional controllers  46 ,  50 , and  54  can be operated independently from each other or together. 
     The warp fiber arms  26  may be on the positional controller  50 , attached to the fill fiber wand controller  46 , or attached to the base positional controller  54 . 
     In this example, at least the positional controller  54  is a six-axis controller, and may be a six-axis robotic controller. That is, the positional controller  54  is able to move the base  22  relative to the warp fiber arms  26  in three dimensions and rotate around three axes. The positional controllers  46  and  50  may have similar characteristics. 
     Referring to  FIGS. 2-8  with continuing reference to  FIG. 1 , the woven structure  14  includes multiple picks  58 . In this example, warp fibers  42  are crossed over a first section  62  of the fill fiber  30  to form one of the picks  58   a . The warp fiber arms  26  are actuated to cross the warp fibers  42  over the fill fiber  30 , which entraps the fill fiber to form the pick  58   a.    
     The example fill fibers  30  and warp fibers  42  may be composed of several different materials including glass, graphite, polyethelene, aramid, ceramic, boron. One of the fill fibers  30  or warp fibers  42  may include hundreds or thousands of individual filaments. The individual filaments may have diameters that range from 5 to 25 microns, although boron filaments may be up to 142 microns in diameter. 
     In this example, each of the warp fiber arms  26  holds one of the warp fibers  42 . In other examples, the warp fiber arms  26  may hold several of the warp fibers  42 . After crossing the warp fibers  42  over the fill fiber  30 , the warp fiber arms  26  hand-off the warp fiber  42  to another of the warp fiber arms  26 . The “hand-off” feature allows an open shed so that the warp fiber arms  26  do not interfere with the wand  18 . After the hand-off, the warp fiber arms  26  are then crossed over a second section  62   b  of the fill fiber  30  to form another of the picks  58   b.    
     The warp fiber arms  26  engage portions of the warp fibers  42 . These portions may include end fittings. The warp fiber arms  26  grab the end fittings holding the warp fibers  42 . The end fittings may be placed on a holding station to help maintain the position of the warp fibers  42  during weaving. 
     A person having skill in this art and the benefit of this disclosure would understand how to create picks by crossing warp fibers over a fill fiber, and how to hand-off a warp fiber from one warp fiber arm to another warp fiber arm. 
     When weaving, the wand  18  moves the fill fiber  30  past the warp fibers  42 . The wand  18  moves the fill fiber  30  back and forth to create built-up layers of picks  58 . The wand  18  is long enough to reach down through the longest warp fibers  42  during the weaving ( FIG. 8 ). 
     In this example, the base  22  is moved as dictated by the design of the woven structure  14  to create a bend  66  in the woven structure  14 . The base  22  is thus capable of movement relative to the warp fiber arms  26 . A boss  68  of the base  22  directly engages one end of the warp fibers  42 . The warp fibers  42  are adhesively secured to base  68  in some examples. 
     The base  22  moves so that the pick_formation point is at a position relative to the wand  18 , and the fill fiber  30 , appropriate for forming the bend  66 . Although only one substantial bend  66  is shown, the base  22  may manipulate the pick formation points to form a woven structure having various contours. 
     The base  22  may move the warp fibers  42  over a piece of tooling shaped to the final desired contour [e.g., a mandrel] that is attached to the base  22  to facilitate forming the bend  66 . The mandrel may move separately from the base  22 . In another example, the base  22  moves the warp fibers  42  without a mandrel to free-form the bend  66 . 
     In some examples, the warp fibers  42  are rigid enough to cantilever out from the base  22  (or shed) during the weaving. A binding agent such as polyvinyl alcohol is used, in some examples, to provide a degree of rigidity to the warp fibers  42 . The warp fibers  42  may have a fixed length. The fill fiber  30 , by contrast, can have length in excess of that needed to produce one component. 
     In some examples, the warp fibers  42  are soft and not rigid enough to cantilever out from the base. In other examples, metallic or plastic fittings may be added to the free ends of flexible warp fibers  42 . The fittings may be placed in holding stations, and the warp arms move the fittings from notch to notch as appropriate as the component is build up. 
     The fittings may take the form of a bead with a through-hole. Prior to weaving, the ends of the warp fibers  42  are inserted through the holes and bonded with an adhesive. The holding station may be a fixture that has notches to hold the non-rigid warp fibers by draping the fitting over the notch and having gravity provide tension. The fittings may also take the form of mechanisms that provide tension by the action of a spring, similar to carriers that hold spools of fiber on a braiding machine. The holding station may be attached to the base or may be independent of the motion of the base. 
     The path and manipulations of the base  22  with the positional controller  54 , the number of warp fibers  42  engaged by the warp fiber arms  26  when forming each pick, and the sequence of warp fiber arm movements may be designed and pre-planned in a software model to produce the woven structure  14  having the desired contours. A stable shape is obtained by the interplay of fiber forces and friction within the textile unit cells throughout the component. 
     The software model may utilize as inputs: a CAD definition of the surfaces of a desired component incorporating the woven structure; a definition of the initial warp fibers&#39; lengths, locations, and orientations; and a definition of a textile repeating unit cell (or pick). The software calculates motions of the wand  18 , base  22 , and warp fiber arms  26  necessary to achieve desired contours in the woven structure  14 , without colliding into each other. The software model is then used as input for the positional controllers  46 ,  50 , and  54 . 
       FIGS. 9A-9C  show an example of the manipulation and sequencing used when weaving to create the woven structure  14 . The warp fibers  42  of this example may be attached to a base having a profile matching a portion of the woven structure  14 . The fill fiber  30  is then moved through the warp fibers  42  in multiple passes. The warp fibers  42  are then turned about an axis A in a direction D to develop, for example, a flange of the woven structure  14  and the bend  66 . 
       FIG. 10  shows an example warp manipulation station  70  having four warp fiber arms  26   a - 26   d . Two of the arms  26   a  and  26   c  selectively engage the warp fiber  42   a , and two of the arms  26   b  and  26   d  selectively engage the warp fiber  42   b . Each of the arms  26   a - 26   d  may have a gripper  74  in order to push and pull the respective-warp fiber  42   a  or  42   b  over the fill fiber  30 . 
     In this example, after forming a pick, the arm  26   a  hands-off the warp fiber  42   a  to the arm  26   d , and the arm  26   c  hands-off the warp fiber  42   b  to the arm  26   b . By handing off and retracting, the warp arms divide the warp fibers  42   a  and  42   b  to open a shed area between the warp fibers  42   a  and  42   b  for the wand  18 . 
     Separation S 1  between arms  26   a  and  26   b , and separation S 2  between arms  26   c  and  26   d  can be adjusted to adjust the shape of the woven structure  14 . The separations S 1  and S 2  may remain relatively consistent when forming the area shown in  FIG. 5 . The separations S 1  and S 2  may be gradually increased after each pass of the fill fiber  30  to create a flanged area of the woven structure  14  shown in  FIG. 4 . 
     Referring to  FIG. 11 , in some examples a woven structure  14   a  may include multiple layers of the warp fibers  42 . The fill fiber  30  joins all three layers in this example. Grippers used when weaving the woven structure  14   a  selectively engage one, two, or more warp fibers. 
     In another embodiment the warp fiber arms  26   a - 26   d  may be mounted on a housing with the fill fiber wand  18 . The warp fiber arms  26   a - 26   d  may have small paddle extensions that can be inserted next to the warp fibers  42 , and are under multi-axis position control with respect to the fill fiber wand  18 , to nudge and guide the warp fibers  42  into position as dictated by the software model of the component being created. 
     Features of the disclosed examples include a relatively precise and repeatable mechanized process that is conducive to high volume production of complex shape engine components. Creation of textile architectures that avoid the pitfalls of traditional methods of low intralaminar and interlaminar properties is enabled. 
     The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of legal protection given to this disclosure can only be determined by studying the following claims.