Patent Publication Number: US-10773469-B2

Title: Systems and methods of converting fiber into shaped fabric plies for composite preforms and products

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Patent Application Ser. No. 62/461,733, entitled SYSTEMS AND METHODS OF CONVERTING FIBER INTO SHAPED FABRIC PLIES FOR COMPOSITE PREFORMS AND PRODUCTS, filed on Feb. 21, 2017, which is hereby incorporated by reference as if set forth in full in this application for all purposes. 
    
    
     BACKGROUND 
     The present application relates to manufacturing, and more specifically to apparatuses and methods for arranging fibers in particular shapes for use in creating composite preforms and products. 
     Fiber-reinforced composite materials, referred to herein as composites, are materials comprised of fibers embedded in a matrix material. Typical fibers include but are not limited to glass fibers, carbon fibers (e.g. graphite fibers and/or more exotic forms of carbon, such as carbon nanotubes), ceramic fibers, and synthetic polymer fibers, such as aramid and ultra-high-molecular-weight polyethylene fibers. Typical matrix materials include but are not limited to thermoset resins, such as epoxies, vinylesters, and polyurethanes and thermoplastic resins, such as polyamides and PEEK (PolyEther Ether Ketone), as well as other non-plastic materials such as metals and ceramics. 
     Composite materials often combine high-strength and relatively light weight. In typical composite products, the fibers provide high tensile strength in one or more directions and the matrix material hold the fibers in a specific shape. A set of fibers roughly in the shape of a final product is referred to as a preform. Preforms are comprised of layers of woven or non-woven fabrics, each of which is cut and arranged into a desired shape. Each cut fabric piece is referred to as a ply. Multiple plies of varying shapes and fabric types are often stacked in different orientations to provide strength and stiffness optimized for the intended usage of the final product. 
     Plies may be assembled into a preform, which is a fabric shape approximating the shape of the desired part. The preform may be fabricated outside of the mold or other rigid structure, and then placed as a unit within the mold or other rigid structure for molding. Alternatively, individual plies may be assembled inside or on a mold, mandrel, plug, or other rigid structure in the shape of the desired finished part. The process of assembling a preform or placing plies within a mold is referred to as layup. 
     Following the layup of a preform and/or plies, the plies may be solidified into a rigid part by adding and/or activating a matrix material. A matrix material, such as uncured polymer resin, may be embedded in the fabric prior to cutting plies (referred to as a pre-impregnated or prepreg material) or applied to or infused into the fabric during or after the fabric layup process, using processes including but not limited to such as wet layup, wet compression molding, or vacuum and/or pressure assisted resin transfer molding. The matrix material is then cured or hardened, often under elevated temperature and/or pressure differentials to ensure even distribution of the matrix material and prevent voids, air bubbles, or other internal defects. Pressure, heat, and/or electromagnetic energy, such as ultraviolet light or microwave energy, may be applied to the composite part during curing using techniques including but not limited to compression molding, vacuum bags, autoclaves, inflatable bladders, and/or curing ovens. 
     However, use of conventional fiber cloth and associated cloth-forming and preform-construction techniques can be particularly expensive due to waste and processing steps. Weaving or binding fibers into fabric adds substantial costs on top of the fiber costs. After cutting, there are often substantial amounts of scrap fabric that are too small and/or irregularly shaped to be useful. This waste cost is exacerbated if the fabric includes pre-impregnated matrix material. Furthermore, the optimal arrangement or nesting of plies for cutting is often different than the arrangement or order required for layup; therefore, additional labor or automation costs are required to collate cut plies into the correct layup quantities and order, referred to as kitting. 
     Additionally, it is often difficult to conform flat fabrics to curved shapes due to the stiffness, inelasticity, and resistance to shearing of the fabric material. Additionally, it is difficult to conform fabric to some types of non-planar (e.g. curved) shapes due to characteristics of the shape itself, such as regions of non-zero Gaussian curvature. These difficulties conforming fabric can lead to additional layup costs and material waste. 
     SUMMARY 
     An example embodiment discloses an apparatus and associated system for creating a ply representing a layer of fibers arranged in a predetermined shape. The example apparatus includes a first mechanism for defining a shape of a ply to be created. A second mechanism employs pins to selectively pull a fiber tow (also simply called a tow herein) into the shape by moving the pins into positions defined by an outline of the shape as determined by the first mechanism. A third mechanism facilitates binding adjacent paths of the fiber tow (which form a web) that extend across or over the shape, thereby resulting in a first ply of the predetermined shape. 
     In a more specific embodiment, the apparatus further illustrates a fourth mechanism for releasing the ply from contact with the pins. The fourth mechanism further includes a mechanism for cutting the fiber tow loose from each pin using a blade. The blade may be a separate blade coupled to each pin. Alternatively, or in addition, the blade includes a flexible blade arranged to conform to a path as defined by the positions of the pins defined by an outline of the shape. The shape may be a three-dimensional shape, e.g., a shape exhibiting a doubly curved surface (also called a non-zero Gaussian surface herein). 
     Another embodiment uses a template for defining the shape. The template includes edges (e.g., edges of an interior cutout of the template, or on the outside of a platen, when the platen is used as a template) that restrain or otherwise fix positions of the pins on opposite sides of the template, such that the fiber tow drapes over (or under) the template. 
     The template may include a three-dimensional template, e.g., when the predetermined shape includes a three-dimensional shape. In certain implementations, the three-dimensional template is used as a heatable platen (e.g., equipped with resistive heating elements), that is readily usable to activate thermally sensitive binder material included in the tow, so as to implement the third mechanism. 
     An additional mechanism may enable selective rotation of the three-dimensional template (which may also act as a platen), from a first orientation to a second orientation, to facilitate creating a second ply of the predetermined shape. The paths of the tow of the second ply are angled differently from paths of the tow of the first ply, depending upon the angle by which the three-dimensional template has been rotated when transitioning to the second orientation. 
     In an illustrative embodiment, shape includes plural sub-shapes that comprise shapes of a kit for a preform. The associated template may exhibit plural shapes (e.g., defined by cutouts), wherein the template and associated plural shapes define the terminal positions of the pins. The template may include and/or be used with a platen that facilitates both defining the plural shapes and binding or fixing the fiber tow, e.g., via application of heat. The binder material may include meltable or heat-curable fibers or filaments, e.g., polyester, nylon, etc. Alternatively, or in addition, the fiber tow includes pre-impregnated fiber tow, which has been pre-treated with a binder material that can be thermally activated. Alternatively, another type of binder, e.g., spray glue, may simply be sprayed over the fiber web to facilitate forming the shaped ply from the web. 
     Various embodiments further show use of a mechanism for drawing fiber from a supply of fiber along a fiber axis between two opposing sets of pins; and a mechanism for moving the opposing pins across an initial center fiber axis to form the fiber web in the predetermined shape. Accordingly, an accompanying example method includes drawing fiber tow from a supply along a fiber axis between two offset opposing sets of pins; moving the pins across the fiber axis to form a fiber web in the desired ply shape; fixing the fiber web to form a shaped ply; and releasing the shaped ply. 
     Hence, various embodiments discussed herein afford substantial benefits over conventional systems and methods for creating fiber plies for use in construction of composite products and/or associated preforms. By enabling rapid generation of multi-dimensional plies using a single tow by selectively moving pins to create a web that is deformable around surfaces, embodiments discussed herein can not only substantially reduce waste (e.g., from scrap material), but can minimize time consuming and error-prone labor that is conventionally required to create plies for use in constructing composite preforms and associated structures. In addition, embodiments discussed herein may substantially eliminate labor and materials costs required to obtain conventional woven fiber fabric. 
     Furthermore, the movable pins of various embodiments discussed herein facilitate creating multiple different shapes simultaneously, thereby obviating a conventionally tedious kitting process that otherwise may involve cutting different shapes of material from expensive fabric; collating the different pieces into a bin; sorting the pieces, and so on, in preparation for layup and creation of composite preforms and associated composite products. 
     In summary, various embodiments enable conversion of fiber directly into shaped plies, thereby bypassing expensive fabric formation and conventional wasteful pile-formation steps. Plies with interior cutouts; plies with flat and/or doubly curved surfaces; sequences of strategically shaped plies; and so on, can all be efficiently and rapidly generated using embodiments discussed herein. 
     Furthermore, various embodiments discussed herein are readily adaptable for use with various linear actuators and/or other programmable electromechanical systems, thereby providing additional substantial flexibility and versatility for fabricating arbitrary ply shapes and arbitrary sequences of plies. 
     A further understanding of the nature and the advantages of particular embodiments disclosed herein may be realized by reference of the remaining portions of the specification and the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates a first example apparatus for creating a web of fabric in a predetermined shape via selective movement of pins across a fiber axis, and for facilitating binding the resulting web of fabric into a shaped ply. 
         FIG. 1B  illustrates the first example apparatus of  FIG. 1A  after fiber tow is pulled from a spool of fiber tow along a fiber axis between offset opposing sets of tow guide pins via a pulling mechanism that is coupled to an arm equipped with a tow-gripping mechanism. 
         FIG. 1C  illustrates the first example apparatus of  FIG. 1B  after the opposing sets of pins are actuated into the predetermined shape corresponding to the shape of a ply to be formed by binding the fibers of the web created between the opposing sets of pins. 
         FIG. 2A  illustrates a second example apparatus for selectively creating a shaped ply using a pin plate and a cam plate with pin-guide channels to create a shaped ply, wherein the shape of the ply is determined by terminal positions of the pins. 
         FIG. 2B  illustrates the second example apparatus of  FIG. 2A  after the pin plate has been partially moved relative to the cam plate, thereby causing pins in the pin plate to move along the pin-guide channels of the cam plate. 
         FIG. 2C  illustrates the second example apparatus of  FIG. 2B  after the pin plate has been fully moved relative to the cam plate, thereby causing pins in the pin plate to be positioned along an outline defining a predetermined ply shape. 
         FIG. 2D  illustrates the second example apparatus of  FIG. 2C  after a shaped platen of the cam plate has been pressed against an underlying fiber web formed between the opposing pins, wherein a shape of the underlying surface of the platen defines the shape of a ply to be formed by the second example apparatus. 
         FIG. 2E  illustrates the second example apparatus of  FIG. 2D  after curved blades, which are aligned with a path defined by the positions of the opposing pins, are used to cut the underlying shaped ply, thereby facilitating releasing the resulting shaped ply from the second example apparatus. 
         FIG. 3A  illustrates a third example apparatus for creating shaped plies, which uses a template with a strategically shaped cutout, spring-loaded pins, and pin-movement arms to facilitate movement of the pins, such that the pins eventually move to positions along a path defined by the shaped cutout of the template; thereby creating a fabric web in the shape of the shaped cutout. 
         FIG. 3B  illustrates example pins that are usable with the third example apparatus of  FIG. 3A . 
         FIG. 3C  illustrates the third example apparatus of  FIG. 3A  after example pins are allowed to partially move in response to movement of the pin-movement arms. 
         FIG. 3D  illustrates the third example apparatus of  FIG. 3C  after the example pins reach terminal positions defined by interior edges of the shaped cutout, as the pin-movement arms are fully separated. 
         FIG. 3E  illustrates a second example template that is usable with the third example apparatus of  FIG. 3A , which includes plural cutouts for an example kit to be created using the third example apparatus of  FIG. 3A . 
         FIG. 4A  illustrates an example set of pin guides and pins therein, which are usable with embodiments and principles discussed herein, and wherein spacings (along the initial fiber axis) of the pin guides and accompanying pins can be selectively adjusted, e.g., via springs or an underlying scissor assembly, thereby facilitating control over variations in fiber density of a web formed between the pins after actuation of the pins along the pin guides. 
         FIG. 4B  is a top view of the example set of pin guides and pins of  FIG. 4A . 
         FIG. 4C  is a top view of the example set of pin guides and pins of  FIG. 4A  after spacings between the pin guides and pins have been fully minimized, and after the accompanying pins have passed across the initial fiber axis, thereby resulting in a relatively tight weave for any subsequently formed shaped ply defined by the terminal pin positions. 
         FIG. 4D  illustrates an example selectively angled pin that is usable with the pin guides of  FIG. 4A . 
         FIG. 5A  illustrates a forth example apparatus with pins mounted on telescoping slides, which are usable to create an open space beneath a three-dimensional rotatable platen, which can be used, in accordance with embodiments and principles discussed herein, to create multiple similarly shaped three-dimensional plies (i.e., plies with doubly curved surfaces) and preforms with crisscrossed fiber patterns. 
         FIG. 5B  illustrates an example fiber pattern of a single ply created using the example embodiment of  FIG. 5A . 
         FIG. 5C  illustrates an example fiber pattern formed by two stacked plies with different fiber orientations but similar shapes as created by the fourth example apparatus of  FIG. 5A . 
         FIG. 6  is a flow diagram of first example method implementable via embodiments discussed herein. 
         FIG. 7  is a flow diagram of a second example method implementable via embodiments discussed herein. 
         FIG. 8  is a general block diagram of an example computing system usable to control operation of embodiments discussed herein when the embodiments are automated. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Methods and devices for manufacturing fiber preforms and finished 3D composite products and fabric plies used to construct these preforms and products. For the purposes of the present discussion, a composite material may be any material that includes one or more fibers that are embedded in a matrix material. An example of a composite material is carbon fiber reinforced polymer. 
     For clarity, certain well-known components, such as hard drives, processors, operating systems, power supplies, actuators, stacks of templates or platens, pick-and-place robots, user interface display screens, control software for automated implementations of embodiments, and so on, are not necessarily explicitly called out in the figures. However, those skilled in the art with access to the present teachings will know which components to implement and how to implement them to meet the needs of a given implementation. 
       FIG. 1A  illustrates a first example apparatus  10 , i.e., system, for creating a web of fabric in a predetermined shape via selective movement of pins  12 ,  14  across a fiber axis (coinciding with or inline with an initial path of a tow  32 ), and for facilitating binding the resulting web of fabric into a shaped ply. 
     The example system  10  includes a fiber tow (also simply called tow herein) pulling mechanism  18 , e.g., an actuator, coupled to an arm  16  that includes a tow-gripping mechanism  24  and accompanying gripping surface for gripping tow  32  that originates from a fiber spool  20 . The spool  20  may be accompanied by a tensioner  22  to facilitate adjusting the initial tension of the tow  32  as it is being pulled by the tow-pulling mechanism  18 . 
     The exact initial tension on the tow  32  is implementation specific and may vary. Those skilled in the art with access to the present teachings may readily adjust the tension of the tow  32  to meet the needs of a given application, without undue experimentation. 
     The tow  32  is pulled by the tow-pulling mechanism  18  and accompanying arm  16  and tow-gripping mechanism  24  along the initial fiber axis that extends between opposing and offset (i.e., offset relative to each other in  FIG. 1A ) sets of pins  12 ,  14 . In the present example embodiment, the sets of pins  12 ,  14  are positioned in a pin plate  26  and are movable along respective pin slots  30 ,  28 . 
       FIG. 1B  illustrates the first example apparatus  10  of  FIG. 1A  after fiber tow  32  is pulled from the spool of fiber tow  20  along a fiber axis between offset opposing sets of tow guide pins  12 ,  14  via the tow-pulling mechanism  18  that is coupled to the arm  16 , which is equipped with the tow-gripping mechanism  24 . In  FIG. 1B , the tow  32  has been pulled past a topmost pin of the sets of pins  12 ,  14 , such that the tow  32  fully extends between opposing sets of pins  12 ,  14  along the initial fiber axis, which is coincident with the path of the tow  32  shown in  FIGS. 1A and 1B . 
       FIG. 1C  illustrates the first example apparatus of  FIG. 1B  after the opposing sets of pins  12 ,  14  are actuated into the predetermined shape  34  corresponding to the shape of a ply to be formed by binding the fibers of a fiber web  36  created between the opposing sets of pins  12 ,  14 . 
     As shown in  FIG. 1C , the sets of pins  12 ,  14  have passed each other across the initial fiber axis, as allowed, in part, by the pin offsets relative to adjacent pins of each pin. Accordingly, note that the first set of pins  12 , which were initially to the left of the initial fiber axis (as shown in  FIGS. 1A and 1B ) are now on the right of the initial fiber axis. Similarly, the second set of pins  14  are now positioned to the left of the initial fiber axis. 
     In summary,  FIGS. 1A-1C  illustrate an example general embodiment and its basic operation and associated concepts, which are usable by various embodiments discussed herein and more fully below. In  FIG. 1A , a fiber supply, e.g., the fiber spool  20 , provides one or more fibers, e.g., in the form of tow, which is used to form plies. 
     The fiber may include carbon fiber, glass fiber, aramid fiber, or any other type of fiber suitable for use in composite materials. The use of the term tow herein in used to refer to fibers generally in tow, yarn, tape, thread, cord, or other fibrous or filamentary form. The arm  16  or other actuated mechanism attaches itself (or is otherwise manually attached) at or near the end of the fiber via the fiber gripping mechanism  24 . The arm  16  is positioned between the two sets of pins  12 ,  14 . 
     In  FIGS. 1A and 1B , the first set of pins  12  is located on the left side of the arm  16 , and the second set of pins  14  is located on the right side of the arm  16 . The pins  12 ,  14  may be simple cylindrical pins or, as described in further embodiments below, include mechanical features for interfacing with and manipulating fiber, e.g., corresponding to the tow  32 . 
     In  FIGS. 1A and 1B , the arm  16  or other mechanism pulls additional fiber from the fiber supply  20 , so that the fiber runs along an initial axis up to or past the length of the rows of pins  12 ,  14 . The initial path of the fiber is called the fiber axis. In an embodiment, a tensioning system, e.g., which may be incorporated into the fiber spool  12 , holds the fiber taut while it is being pulled by the tow-pulling mechanism  18 . 
     In  FIG. 1C , the some or all of pins  12 ,  14  move from their initial positions to opposite sides of the fiber axis and engage with the taut fiber  32 . Because the pins  12 ,  14  are staggered in position, they are free to pass by the adjacent pins in the other pin set. The pins  12 ,  14  then move further past the fiber axis to positions defining a pair of edges (e.g., the left and right edges of the shape  34  of  FIG. 1C ) of the desired ply shape  34 . As the pins move, they engage the fiber  32 , and additional fiber is released from the fiber supply  20  to form a fiber web  36  in the desired ply shape  34 . The pins  12 ,  14  may move simultaneously or alternatively sequentially, for example alternating between single pins in sets  12  and  14 . In the latter embodiment, each pin may move from its initial position, across the fiber axis, and to its terminal position defining a row of the desired ply shape  34  before the next pin in the sequence moves. 
     As discussed in detail below, this fiber web  36  is then fixed into position, for example by bonding each course of the fiber  32  of the fiber web  36  with its adjacent courses and/or a layer of binding material, and then releasing the resulting ply from the pins  12 ,  14 . 
     The resulting fixed fiber web  36  then represents a shaped ply suitable for use in constructing a composite preform or product. Because this shaped ply is formed directly from the fiber web  36 , there is no need for intermediate processing of the fiber into a fabric and no waste from cutting the plies from the fabric. 
     Following the fixation and release of the fiber web  36  (which has been converted into a ply by bonding adjacent fibers), the pins  12 ,  14  then return to their starting positions on opposite sides of the fiber axis, and the system  10  is ready to form another ply with same or a different shape. 
     The sets of pins  12 ,  14  may be moved from their starting positions, across the fiber axis, and to positions defining edges of the ply shape. In one embodiment, each of the pins  12 ,  14  is driven independently using a linear actuator. Software control of these actuators facilitates moving the pins into arbitrary edge shapes, thereby defining plies with varying shapes. Furthermore, selective pin movement enables arbitrary sequences of plies to be constructed, which eliminates the need for collating cut plies into sets required for a complete part or preform, referred to as kitting. 
     In another embodiment, each of the two sets of pins  12 ,  14  is electromagnetically or mechanically coupled with a rail that may selectively move the pins in respective slots  30 ,  28 . Each rail may be driven by a linear actuator (responsive to control signals) to move the associated pins  12 ,  14  from their initial positions, across the fiber axis, to any position up to end positions at the maximum extent of the pin range of motion. 
     When the pins  12 ,  14  are stopped at predetermined positions along the respective slots  30 ,  28 , e.g., so as to define the ply shape  12 ,  14 , the resultant pin positions are called terminal positions herein. Note that, as the term is used herein, terminal positions do not mean that the pins must stay in those positions, but rather merely suggest that the pins are at their positions needed to define a desired shape for a ply to be created from the accompanying fiber web formed between the pins  12 ,  14 . 
     As each rail moves towards its terminal position, pins  12 ,  14  are selectively electromagnetically or mechanically decoupled from the rail to define the ply edge. After fixing and releasing the shaped ply, the rails reverse direction and then electromagnetically or mechanically re-couple with the pins to return them to their initial positions. 
     Note that embodiments of the invention using linear actuators or other programmable electromechanical systems provide substantial flexibility in fabricating arbitrary ply shapes and arbitrary sequences of plies. However, mass production applications often only require a limited number of ply shapes that are repeated in large quantities. For these applications, embodiments of the invention may use mechanical templates to define ply shapes. Furthermore, in certain implementations, the different sets of pins  12 ,  14  may be manually positioned, e.g., using mechanically tooling. 
       FIG. 2A  illustrates a second example apparatus  40  for selectively creating a shaped ply using a pin plate  26  and a cam plate  42  with pin-guide channels  46 ,  48  to create a shaped ply defined by terminal positions of the opposing pins  12 ,  14 . In  FIG. 2A , the pins  12 ,  14  are at their initial positions in (respective slots  30 ,  28  of the pin plate  26 ) on either side of a fiber axis  50 . The pin plate  26  is positioned below the cam plate  42  and may slide parallel to the cam plate and fiber axis  50 . 
     Top portions of the pins  12 ,  14  ride in respective guide channels  48 ,  46  of the cam plate  42 . The cam plate  42  includes a platen  44  in the desired shape of a ply. The pin guides  46 ,  48  conform to edges of the shaped platen  44 . 
     As the pin plate  26  is moved along the fiber axis  50  toward the platen, the pins  12 ,  14  are guided by the respective guide channels  48 ,  46  which cross at a flap junction  52 . Note that while details of the flap junction  52  are not explicitly shown in  FIG. 2A , those skilled in the art with access to the present teachings will know how to readily implement such a junction to meet the needs of a given implementation, without undue experimentation. 
     As the pins  12 ,  14  travel along their respective guides  48 ,  46 , they cross the fiber axis  50  as they cross the flap junction  52  and eventually reach their terminal positions at opposing sides of the shaped region corresponding to the shaped platen  44 , as discussed more fully below. Note that while the associated tow and accompanying spool and tow-pulling mechanisms are not shown in  FIG. 1C , the initial position of the tow would extend along the fiber axis  50  across the length of the cam plate  42 . 
     The platen  44  is used, in part, to press down on an underlying fiber web formed between the pins  12 ,  14  when the pins reach the terminal positions, as discussed more fully below. This also helps to further flatten and align adjacent fibers of the web, reducing or eliminating any gaps therebetween in preparation for bonding. 
     The inter portions of the pin guides  46 ,  48  are equipped with respective movable blades  56 ,  48  that conform to a path defined by the inner surfaces of the pin guides  46 ,  48 , and outer edges of the platen  44 . The blades are used to release the underlying ply formed by a fiber web formed therebetween, after the web has been bonded, e.g., using heat applied to the platen  44 . Note that the platen  44  may include resistive heating elements to facilitate activating thermally sensitive binder that is included in, with, among, or otherwise deposited on fibers of an underlying web that will be formed once the pins  12 ,  14  (with accompanying tow that snakes therebetween) reach their terminal positions at portions of the pin guides  48 ,  46  that are adjacent to sides of the platen  44  and accompanying curved (or otherwise appropriately shaped) blades  58 ,  56 . The platen  44  may include binder-dispenser nozzles and act as a dispenser for binder material, wherein the dispenser is adapted to apply binder material to at least one surface of the fibers after the fiber tow has been pulled into the desired shape of the ply to be created via the web of fiber tow. 
       FIG. 2B  illustrates the second example apparatus  40  of  FIG. 2A  after the pin plate  26  has been partially moved relative to the cam plate  42  along the fiber axis  50 , thereby causing pins  12 ,  14  in the pin plate  26  to move along the respective pin-guide channels  48 ,  46  of the cam plate  42 . 
       FIG. 2C  illustrates the second example apparatus  40  of  FIG. 2B  after the pin plate  26  has been fully moved relative to the cam plate  42 , thereby causing pins  12 ,  14  in the pin plate  26  to be positioned along an outline defining a predetermined ply shape, which corresponds to opposing edges of the platen  44 . 
     At this stage, when the apparatus has been fitted with tow, a fiber web will have formed under the platen  44  as the tow snakes between offset and opposing pins  12 ,  14 . In  FIG. 2C , the platen  44  has yet to be depressed onto the underlying fiber web (not shown in  FIG. 2C ), and the ply-releasing blades  56 ,  58  have yet to be actuated. 
       FIG. 2D  illustrates the second example apparatus  40  of  FIG. 2C  after a shaped platen  44  of the cam plate  42  has been pressed against an underlying fiber web (not shown in  FIG. 2D ) formed between the opposing pins  12 ,  14 . A shape of the underlying surface of the platen defines the shape of a ply to be formed by the second example apparatus  40 . Note that the bottom surface of the platen  44  may be flat or have a three-dimensional (e.g. curved) shape, such that the resulting ply (to be formed after bonding of the fibers of the underlying fiber web) will be a so-called three-dimensional ply. In this case of a non-planar platen  44 , the apparatus  40  may include a secondary platen or a surface of cam plate  42  mating with the non-planar surface of the platen  44 . 
     At this stage, the curved or otherwise shaped blades  56 ,  58  have yet to be actuated. The platen  44  may be heated, thereby bonding underlying fibers of an underlying fiber web. Note that mechanisms and accompanying methods, other than applying heat, may be used to bind underlying fibers of the fiber web to thereby form a shaped ply from the fiber web. Once the fibers have been bonded into a ply, the curved or shaped blades  56 ,  58  are actuated to cut loose the underlying ply from the apparatus  40 . 
       FIG. 2E  illustrates the second example apparatus  40  of  FIG. 2D  after the curved or otherwise shaped blades  56 ,  58 , which are aligned with a path defined by the positions of the opposing pins  14 ,  12 , are used to cut the underlying shaped ply (in the shape of the platen  44 ), thereby facilitating releasing the resulting shaped ply from the second example apparatus  40 . 
     Note that the shape of the example platen  44  is merely illustrative and may vary. Different shapes and/or multiple shapes of platens may be used individually and/or arranged serially along the fiber axis  50  and used simultaneously to cut multiple shapes. Furthermore, note that the exact size of the pin plate  26 ; the number of pins in the pin plate  26 ; the types of pins used; the spacing between pins along the fiber axis  50  direction; angling of the pins relative to the surface of the pin plate  26 , and so on, are implementation specific and may be varied to meet the needs of a given implementation of the second example embodiment  40 . 
     In summary,  FIGS. 2A-2E  illustrate a mechanical system for fabricating shaped plies. The fiber supply (e.g., the fiber spool  20  of  FIGS. 1A-1C ), fiber tow, tow-pulling mechanisms, arms, tow grippers (e.g., items  16 - 24  of  FIGS. 1A-1C ), and so on are omitted from  FIGS. 2A-2E  for clarity. 
       FIG. 2A  shows the system  40  in an initial configuration. The sets of pins  12 ,  14  are installed in the pin plate  26 , which includes horizontal guide channels  28 ,  30  defining the range of pin motion. The pins  12 ,  14  are also installed in a pair of vertical guide channels  46 ,  48  in the cam plate  42 . In an embodiment, the pin plate  26  is below the pins  12 ,  14 , and the cam plate  42  is above the pins  12 ,  14 . 
     To actuate the pins  12 ,  14  and form a shaped ply, one or more fibers (e.g., fiber tow) are first pulled from the fiber supply (e.g., the spool  20  of  FIGS. 1A-1C ) along the fiber axis  50  between the pins  12 ,  14 , as described above. Next, as shown in  FIG. 2B , the pin plate  26  moves relative to the cam plate  42 , so that the guide grooves  46 ,  48  in the cam plate  42  gradually move the pins  12 ,  14  across the fiber axis  50  to engage the fiber and then further away (from the fiber axis  50 ) to form the edges of the desired shape ply (wherein the edges are approximately coincident with the blades  56 ,  58 ), as shown in  FIG. 2C . A gate mechanism (e.g., labeled  52  in  FIG. 2A ) comprising a pair of joined flaps is used to direct pins along the appropriate guide channel  46 ,  48  as the two guide channels  46 ,  48  in the cam plate  42  cross. 
       FIG. 2C  shows the pin plate  26  at the end of its relative motion with respect to the cam plate  42 , with its guide channels  46 ,  48  defining the edges of the shaped ply. Embodiments of the invention may include interchangeable cam plates, or portions thereof, each of which with different guide channel shapes for rapidly creating different shaped plies. Accordingly, this enables use of the apparatus  40  to rapidly change the shapes of plies to be created. 
     In still further embodiments, a robotic pick-and-place mechanism may select one of a plurality of different cam plates and/or platens from a magazine or rack and automatically load and unload these as needed to form different ply shapes on demand. 
       FIG. 2D  illustrates an embodiment of fixing the fiber web into a shaped ply. In this embodiment, the center portion (e.g., the platen  44 ) of the cam plate  42  moves toward the pin plate  26 , acting as a platen to compress the fiber web against the pin plate  26  and fix it into place. Embodiments of the invention may use adhesives, mechanical fasteners, or binders such as heat-sensitive, pressure sensitive, light sensitive, or any other type of binder material to fix the fiber web. Heat, pressure, light or other energy may be applied through the platen or another part of the system to activate the binder. In some embodiments, the binder, such as a heat-sensitive thermoplastic material, a pressure sensitive adhesive, or a UV-sensitive photopolymer, may be commingled with the fiber as part of the fiber supply, applied on top of the fiber web as a liquid, film, meltable fiber, mesh, or veil, or applied to the platen surface for transfer to the fiber web. 
     Once the platen portion  44  of the cam plate  42  has fixed the fiber web, a pair of curved blades  56 ,  58  coincident with the inside walls of the cam plate guide channels  46 ,  48  is lowered to cut the fiber web inside of the pins  12 ,  14 . This releases the fiber web from the pins  12 ,  14 . 
     In an embodiment, the curved blades  56 ,  58  are similar in construction to those used with steel rule dies. In an alternate embodiment, each pin includes a slot that houses an integral blade. After fixing the fiber web, these blades are extended from their slots in the pins to cut the fiber web. In addition to these blades for cutting the edges of the fiber web, additional embodiments of the invention may include additional die cutters for cutting out interior portions of the web if that is required as part of the desired ply shape. The completed shaped ply may be removed using vacuum, electrostatic, or mechanical effectors. 
     In further embodiments, the completed shaped ply may be placed into a mold or preforming fixture with additional shaped plies to form a complete preform. Adhesives, thermoplastic bonding, mechanical fasteners, stitching, and so on, may be used to bond shaped plies together. These embodiments of the invention may be implemented using robotic manipulators to position each shaped ply in the correct position and orientation in the mold or preforming fixture. Alternatively, a motion stage, including for example X, Y, and theta axes, may be used to move the preforming fixture relative to each shaped ply for placement. 
       FIG. 3A  illustrates a third example apparatus  70  for creating shaped plies, which uses a template  76 ,  78  (which includes two pieces) with a strategically shaped cutout  86 ,  88 , spring-loaded pins  82 ,  92 ,  84 ,  94  (four examples of which are shown, while others have been omitted for clarity), and pin-movement arms  72 ,  74  to facilitate movement of the pins  82 ,  92 ,  84 ,  94 . The pins  82 ,  92 ,  84 ,  94  eventually move to positions (called terminal positions) along a path defined by the shaped cutout  86 ,  88  of the template  76 ,  78 ; thereby creating a fabric web in the shape of the shaped cutout when tow is fed into the apparatus  70  in a manner analogous to that discussed with respect to  FIGS. 1A-1C . 
     In the present example embodiment, the pin-movement arms  72 ,  74  are shown holding the pins  82 ,  84  in initial positions. Note that the other pins  92 ,  94  are further held in place by the templates  78 ,  76 , such that movement of the pin-movement arms  72 ,  74  along a perpendicular axis  80  (i.e., perpendicular and approximately coplanar with the fiber axis  50 ) will not result in movement of the other pins  92 ,  94 . The pin-movement arms  72 ,  74  engage with arm-engagement stubs of the pins  82 ,  84  and selectively confine motion of the pins  82 ,  84 . 
     The pin movement arms  72 ,  74  are movable along the perpendicular axis  80 , e.g., via actuators and/or mechanical mechanisms (or manually) while remaining parallel to the fiber axis  50 . As the pin-movement arms  72 ,  74  move outward (i.e., away) from the fiber axis  50 , spring loading (or other loading) of the pins  82 ,  92 ,  84 ,  94  causes the pins to separate, thereby pulling fiber threaded therebetween into the shape of the cutout  86 ,  88 . 
     Note that the pins  82 ,  92 ,  84 ,  94  need not be spring loaded in all implementations. For example, tooling coupled underneath the apparatus  70  may employ other mechanisms (e.g., weights and accompanying rigging) for applying outward forces on the pins  82 ,  92 ,  84 ,  94 , such that when the pin-movement arms  72  are further separated, the pins  82 ,  92 ,  84 ,  94  exhibit sufficient forces to pull any tow (threaded therebetween) to form a web in the shape of the cutout  86 ,  88  when the pin-movement arms  72 ,  74  fully clear the cutout  86 ,  88 . 
     Furthermore, note that while in the present example embodiment, movement of the pin-movement arms  72 ,  74  is discussed as being along the perpendicular axis  80 , that embodiments are not limited thereto. For example, in some implementations, i.e., implementations whereby pairs of pins are to be positioned, one at a time, to their terminal positions (thereby reducing forces needed to pull the tow), the pin-movement arms  72 ,  74  may be slid out from under the template  76 ,  78  along a direction parallel to the fiber axis  50 . In this case, as ends of the pin-movement arms  72 ,  74  pass the pins  82 ,  84 , the pins are free to move to their terminal positions defined by inner edges of the cutouts  86 ,  88 . 
     Note that the template sections  76 ,  78  can readily be removed and replaced with new or different template sections with different cutouts. The pin-movement arms  72 ,  74  will continue to function with templates with different sizes of cutouts. Accordingly, the apparatus  70 , including the template sections  76 ,  78  may act as a template-changing system that enables an arbitrary number of possibilities for changing out the template shown  76 ,  78  with another template. 
       FIG. 3B  illustrates example pins  90  (including a first pin  92  and a second pin  94 ) that are usable with the third example apparatus  70  of  FIG. 3A . The first pin  92  and second pin  94  include arm-engagement stubs  98 ,  108 , which partially extend from pin bases  104 ,  114 . With reference to  FIGS. 3A and 3B , the pin bases  104 ,  114  ride in slots of the pin plate  26 , while the pin-engagement stubs  98 ,  108  engage the pin-movement arms  72 ,  74 . 
     The first pin  92  includes a tow-engagement section  96 , which includes a first beveled surface  100  for accommodating tow. Similarly, the second pin  94  also includes a tow-engagement section  106 , but with a second beveled surface  110  that is oppositely beveled relative to the bevel of the first beveled surface  100 . The opposite orientations of the bevels facilitate twisting partially flat tow (also called tow herein) from vertical to approximately coplanar relative to a plane parallel to the template  76 ,  78 , e.g., to thereby reduce any spacing between adjacent stretches of tow (which might otherwise exhibit gaps, e.g., when partially flat tows are oriented with the partially flat sides being perpendicular to a plane of the template  76 ,  78 ). 
     For illustrative purposes, the second pin  94  is shown including a tow-cutting blade  112 , which may be used to cut loose a ply from the apparatus  70  of  FIG. 3A  when a platen in the shape of the cutout  86 ,  88  presses portions of the tow that wrap around the tow-engagement section  106  (and ride in a groove characterized by the second beveled surface  110 ). The tow-cutting blade  112  may be fixed and/or retractable, depending upon the needs of a given implementation. 
     Another tow-cutting blade  102  of the first pin  92  is shown retracted into the first tow-engagement section  96 . When using retractable blades, the blades may be selectively actuated, e.g., to extend from the tow-engagement section  96  to selectively cut the tow that warps around the first tow-engagement section  96  (e.g., so as to facilitate releasing a shaped ply). Note that absent use of retractable blades, the blades  102 ,  112  may be used to cut the tow responsive to application of a platen to the associated fiber web during and/or after bonding of the fiber web into a shaped ply. 
     Furthermore, pins need not have individual blades, e.g., the blades  102 ,  112 , for releasing a given shaped ply from the apparatus  70  of  FIG. 3A . For example, other ply-releasing mechanisms, such as flexible blades that snake between pins and ride in blade-holding slots (not shown) that may be cut into the tow-engagement sections  96 ,  106 , could be used to facilitate release of a shaped ply from the apparatus  70  of  FIG. 3A . 
       FIG. 3C  illustrates the third example apparatus  70  of  FIG. 3A  after example pins  82 ,  84  are allowed to partially move in response to movement of the pin-movement arms  72 ,  74  along the perpendicular axis  80  and away from the fiber axis  50 . 
       FIG. 3D  illustrates the third example apparatus  70  of  FIG. 3C  after the example pins  82 ,  84  reach terminal positions defined by interior edges of the shaped cutout  86 ,  88  as the pin-movement arms  72 ,  74  are fully separated. 
     In summary, in  FIGS. 2A-3D , the platen is illustrated as a flat plate. However, as discussed more fully below, further embodiments of the invention may utilize a non-planar platen, such as a platen having a contoured three-dimensional shape corresponding with the shape of all or a portion of a preform. This allows embodiments of the invention to form shaped plies with curvature and non-planar shapes. In this embodiment, additional fiber is pulled from the fiber supply as the platen contacts the fiber web and deforms the fiber web under tension from its substantially flat shape to a curved shape. Because the fiber web is not fixed until after the platen has deformed the fiber web into a non-planar shape, each row of the fiber web is free to move and shear with respect to its neighbor, avoiding many of the problems associated with draping flat fabrics. 
     In still a further embodiment, the platen does not have to match the curved shape of the preform. Instead, the platen may have a profile shape adding extra fiber to each row of the fiber web so that the length of each row matches the length of a geodesic curve of the preform. In this embodiment, portions of the fiber web may not need to be fixed in place when forming the shaped ply, as these fibers will set themselves into the desired position once the shaped ply is placed in the mold or layup tool. 
     In yet another embodiment, the platen may be omitted and a set of actuated pins may be used to flatten and fix the fiber web. The set of actuated pins may be a two-dimensional array covering the entire work area of the system, or alternatively a one-dimensional array mounted on a moving rail to flatten and fix each row of the fiber web in sequence. In the latter example, the rail may move from the farthest side of the pin plate towards to the fiber supply, so that additional fiber may be supplied as needed if forming non-planar shaped plies. 
     In some applications, shaped plies may require interior cuts or concave edges between adjacent pins. For these applications, the platen may include additional blades to cut excess portions of the shaped ply away after the fiber web has been fixed. 
     It may be desirable for some applications to steer the fiber around interior holes or concave edges, rather than cutting away excess fibers. In an embodiment, conical protrusions in the platen may be used to direct the fiber web along curved paths around interior holes and concave edges. 
       FIGS. 3A-3D  illustrate another mechanical template system for forming shaped plies. In  FIGS. 3A-3D , the platen for fixing the fiber web and the fiber supply are omitted for clarity. The embodiments of  FIGS. 3A-3D  operate in a similar manner as described above, including drawing fiber from a supply along a fiber axis between two sets of pins, moving the pins across the fiber axis to form a fiber web in the desired ply shape, fixing the fiber web to form a shaped ply, and releasing the shaped ply. However, the embodiments of  FIGS. 3A-3D  utilize a different mechanism for moving pins to the shape of the edges of the desired ply shape. 
       FIG. 3A  illustrates a pin plate including guide channels for defining ranges of pin motion. Pins are inserted into the pin plate guide channels. In  FIGS. 3A-3D , only a portion of the pins are shown for clarity. 
       FIG. 3B  illustrates details of an embodiment of the pins. In this embodiment, the odd and even guide channels of the pin plate use pins with conical recesses facing upwards and downward, respectively. The conical recesses tilt the fiber at an angle with respect to the pin plate to assist in consistently flattening the fiber with the platen (not shown). By alternating the direction of the conical recesses in adjacent pin guide channels, the angle of the fiber as it engages with the conical recesses remains the same and the fiber is prevented from twisting as the web is formed. Additionally, in this embodiment, each pin includes extension with a boss at the end. 
     Returning to  FIG. 3A , a pair of moveable pin arms is located above the pin plate. Each pin arm engages with the bosses of either the odd or even row pins. The moveable pin arms allow the odd and even row pins to move from their initial positions, across the fiber axis, and to the edges of the pin plate. The extension arms and bosses on the pins ensure that each moveable pin arm does not have to cross the fiber axis and does not mechanically interfere with the other pin arm or the other set of pins. 
     In one embodiment, the pins are pushed from their initial positions towards the edges of the pin plate by springs or counterweights. In this embodiment, pins are pressed against the moveable pin arms. As the moveable pin arms move outward, the pins remain in contact with the pin arms. This is illustrated in  FIG. 3C . In an alternate embodiment, magnets or mechanical latches are used to keep the pins in contact with the pin arms as the pin arms move outward. 
     A mechanical ply template corresponding with the desired ply shape is placed over the pin plate and the moveable pin arms. As the moveable pin arms allow the pins to move towards the edge of the pin plate, the pins come into contact with portions of the mechanical ply template. The mechanical ply template stops the motion of the contacting pins, while allowing the moveable pin arms and uncontacted pins to continue their outward motion. When all of the pins have come into contact with the mechanical ply template, the pins are arranged in the shape of the edges of the desired ply shape. 
     The movements of the pin arms and pins illustrated by  FIGS. 3A-3D  are used to form a fiber web. Similar to the other embodiments, the fiber web is then fixed to form a shaped ply, and the shape ply is released from the pins and removed from the system. After the shaped ply is removed, the pin arms reverse direction and return to their initial positions. As the pin arms move inward, they reengage with the pins and move them away from the mechanical ply template back to their initial positions on the opposite sides of the fiber axis. This embodiment is then ready to form another shaped ply. 
     Embodiments of the invention may include interchangeable ply templates, or portions thereof, each of which with different edge shapes, to quickly change ply shape. In still further embodiments, a mechanism may select one of a plurality of different ply templates from a magazine or rack and automatically load and unload these as needed to form different ply shapes on demand. In addition, a ply template may include portions that retain pins in their initial positions, allowing the formation of ply shapes that are less than the full length of the pin plate. This is shown in  FIG. 3D , with one pair of pins retained in its initial position even after the pin arms have moved to their outside motion limits. In still further embodiments, each ply template may be used to form two or more shaped plies at the same time, with the same or different shape. 
       FIG. 3E  illustrates a second example template  120  that is usable with the third example apparatus  70  of  FIG. 3A , which includes plural cutouts  136 - 146  for an example kit to be created using the third example apparatus  70  of  FIG. 3A . The second example template  120  includes a first template section  126  and a second template section  128  that are used to form a first cutout  136 ,  138 , a second cutout  140 ,  142 , and a third cutout  144 ,  146 , that facilitate simultaneous production of plies in the shapes defined by the cutouts. 
     Note that in practice, and during operation, the first template section  126  and the second template section  128  may be moved together along the perpendicular axis  80 , analogous to what is shown in  FIG. 3A . During use, distances between the template sections  126 ,  128  as measured along the perpendicular axis may vary, e.g., depending upon initial pin spacing (when the pins are at their initial positions) and depths of template teeth  130 . 
     Furthermore, note that spacing of the cutouts  136 ,  138 ;  140 ,  142 ; and  144 ,  146  may be moved closer together along the fiber axis  50 , e.g., if extra tow between the cutouts  136 ,  138 ;  140 ,  142 ; and  144 ,  146  is not to be used for the kit to be formed. Furthermore, note that the cutouts  136 ,  138 ;  140 ,  142 ; and  144 ,  146 , which represent plural sub-shapes, may form all or only a portion of a kit, or may be completely unrelated, i.e., not part of a given kit. 
       FIG. 4A  illustrates an example set of pin guides  170  (including a first set of pin guides  176  and a second set of pin guides  178 ) and accompanying and pins  180  therein are usable with embodiments and principles discussed herein. Spacings (along the initial fiber axis  50 ) of the pin guides  176 ,  178  and accompanying pins  180  can be selectively adjusted, e.g., via springs  182  or an underlying scissor assembly, thereby facilitating control over the tightness of the fiber web formed between the pins  180  after actuation of the pins  180  along the pin guides  176 ,  178 . 
       FIG. 4B  is a top view of the example set of pin guides  176 ,  178  and pins  180  of  FIG. 4A . As shown in  FIG. 4B , the pins guides  176 ,  178  are sufficiently separated (i.e., spaced) along the fiber axis  50  to facilitate accommodation of relatively thick tow, while still allowing the pins  180  to readily pass each other when crossing the fiber axis  50 . 
       FIG. 4C  is a top view of the example set  170  of pin guides  176 ,  178  and pins  180  of  FIG. 4A  after spacings between the pin guides  176 ,  178  and pins  180  have been fully minimized, and after the accompanying pins  180  have passed across the initial fiber axis  50 . Movement of the pin guides  176 ,  178  closer together along the fiber axis  50  after the pins  180  have crossed the fiber axis  50  facilitate creating a relatively tight weave for any subsequently formed shaped ply that is defined by the terminal pin positions. In the present example embodiment, the terminal positions of the pins  180  as shown would define a rectangular shape for a fiber web that includes tow that snakes between pins of the first pin guides  176  and pins of the second pin guides  178 . 
       FIG. 4D  illustrates an example selectively angled pin  180  that is usable with the pin guides  176 ,  178  of  FIG. 4A . The example pin  180  includes an angled pin protrusion  190 , the curved surface of which includes or represents a fiber-engaging surface, i.e., a surface that makes contact with fiber as a fiber web is being constructed. 
     An example fiber path  198  extends around a backside of the protrusion and is retained against the angled protrusion  190  via retaining lip  192 . With reference to  FIGS. 4A and 4D , note that the angles of the fiber-engaging surfaces of adjacent pins (i.e., adjacent along the fiber axis  50 ) are oppositely angled. This may facilitate flattening certain types of tow via a platen, thereby facilitating removing or minimizing gaps between adjacent stretches of tow in a given fiber web. 
     Hence,  FIG. 4D  illustrates a detail view of another pin design, as used by the embodiment of  FIGS. 4A-4C . In this pin design, the pins are angled so that the fiber is tilted at an angle with respect to the pin plate to assist in consistently flattening the fiber with the platen. The direction of pin tilt is mirrored for adjacent pin channels as shown in  FIGS. 4A-4C , so that the angle of the fiber as it engages with the angled pins remains the same, and the fiber is prevented from twisting as the web is formed. In a further embodiment, the retaining lip  192  is included near the base of the angled pin protrusion  190  to retain the fiber in a fixed position (i.e., to fix the fiber path  198 ) as the fiber web is flattened with the platen. Additionally, in this embodiment, each pin optionally includes an extended body  194  with a protruding boss  196  at the end to allow for its use with pin movement mechanisms such as that illustrated by  FIGS. 3A-3D . 
     In summary, with reference to  FIGS. 4A-4E , the spacing (along the fiber axis  50 ) between the pin guides  176 ,  178  can be varied to adjust the angular orientation of the fibers in the fiber web and reduce or eliminate gaps between adjacent rows of the fiber web.  FIG. 4A  illustrates a perspective view of an embodiment of the invention with the pins located at the maximum spacing.  FIG. 4B  illustrates a top view of the same configuration. 
     In the embodiment of  FIGS. 4A-4E , the pin plate (e.g., pin plate  26  of  FIG. 3D ) with guide channels used in other embodiments is replaced by a set of separate pin guides  176 ,  178 , with each pin  180  constrained by its own pin guide  176 ,  178 . 
     The pin guides  176 ,  178  may be moved independently to adjust the spacing (along the fiber axis  50 ) between pins  180 , and hence the spacing and angular orientation of the rows of fiber in the fiber web (e.g., the web made from fiber tow that snakes between the pins  180 ). In an embodiment, it is desirable to set the pin spacing so a line between the fiber engaging surface of one pin and the corresponding surface of the adjacent pin is substantially parallel to the path of pin motion. 
     Embodiments of the invention may move the pin guides in a number of different ways. But, as an example, compression springs  182  couple each pair of adjacent pin guides  176 ,  178 . The outermost pin guides  176 ,  178  can then be moved closer or further apart from each other. If the compression springs in this embodiment have the same spring constant, then the inner pin guides will be equally spaced between the outermost pin guides. 
     In another embodiment, a scissor or tong linkage connects with sliding joints on the pin guides  176 ,  178 . As the linkage is expanded or contracted, the separation between pin guides is increased or decreased accordingly. In still a further embodiment, a sliding cam plate may be moved to adjust the spacing between pin guides. In yet another embodiment, one or more linear actuators may be used to adjust the spacing between pin guides independently. 
     As shown in  FIG. 4B , an embodiment of the invention sets the pin spacing to a larger value when the pins  180  are in their initial positions to ensure adjacent pins  180  can pass each other as they move across the fiber axis  50  to opposite sides of the pin channels in the pin guides  176 ,  178 . After the pins  180  have passed across the fiber axis  50  and are clear of their adjacent pins, the pin spacing can be reduced to the desired amount, for example as shown in  FIG. 4C . The independently moving pin guides  176 ,  178  can be used with other embodiments discussed herein, including the example embodiments of  FIGS. 1A-3E . 
       FIG. 5A  illustrates a forth example apparatus  200  with pins  208 ,  218  mounted on telescoping slides  203 ,  214 , which are usable to create an open space beneath a doubly-curved rotatable platen  220 . The three-dimensional platen  220  exhibits a curved surface that will act as both a template and a platen to facilitate creating similarly shaped three-dimensional plies (i.e., plies with curved surfaces) and preforms with crisscrossed fiber patterns. 
     For clarity, only two opposing pins  208 ,  218  and accompanying sliding members  204 ,  214  are shown. Telescoping drive mechanisms  202 ,  212  facilitate selectively moving the pins  208 ,  218  mounted thereon into terminal positions abutting edges of the three-dimensional paten  220 . Fiber tow snaking between opposing pins  208 ,  218  drapes over the doubly curved surface of the platen  220 , forming an example tow path  210  over the surface of the platen  220 . 
     After an initial fiber web (corresponding to the example tow path  210  in  FIG. 5A ) is created, the platen  220  is selectively pressed into the web, e.g., so as to draw out more fiber from a fiber supply (e.g., fiber spool) to accommodate the bulging in the fiber web as needed to create the resulting three-dimensional shaped ply (with a doubly curved surface) conforming to a surface of the three-dimensional platen  220 . The example pins  208 ,  218  include fiber-engaging surfaces of respective slots  206 ,  216 , which may facilitate holding the web  210  to the pins while the platen  220  is extended into the web  210 . 
     Alternatively, or in addition, the web  210  can be sandwiched between two different but complimentary platens, wherein one platen is applied from below the fiber web  210 , and another platen is applied from above the fiber web  210 . 
     In the present example embodiment, the platen  220  is mounted on a rotatable spindle  222 , which may rotate about a rotation axis  230 ; and not just extend and retract along the axis  230  (where vertical movement control represents control over elevation of the platen  220  relative to the movable pins  208 ,  218 ). 
     To fix (i.e., to bind fibers to facilitate creating a ply) the web  210  formed using the three-dimensional platen  220  can include thermally activated binder material among the fibers of the tow. The platen  220  may be heated to bind fibers of the web  210 , and then one or more blades, which may or may not be attached to the pins and/or the platen  220  can then readily be used to cut free the resulting ply from the fourth example apparatus  200 . Note that embodiments are not limited to use with blades to cut plies. For example, laser cutting or other ply-release mechanisms may be employed, without departing from the scope of the present teachings. 
     To create a second ply of a similar shape, but with different fiber orientations, a new web is created, and the platen  220  is rotated by a desired angle, so as to set approximate angles between adjacent fibers when the resulting second ply is released from the apparatus  200  and stacked with the first ply. 
       FIG. 5B  illustrates an example fiber pattern  210  of a single ply  240  created using the example embodiment of  FIG. 5A . The single ply  240  exhibits a curved surface resulting from using the three-dimensional platen  220  of  FIG. 5A . 
       FIG. 5C  illustrates an example fiber pattern  210 ,  232  formed by two stacked plies  250  with different fiber orientations but similar shapes as created by the fourth example apparatus  200  of  FIG. 5A . 
       FIG. 6  is a flow diagram of first example method  260  implementable via embodiments discussed herein. The example method  260  facilitates arranging creating one or more plies. The one or more plies represent one or more layers of fibers that are arranged in a predetermined shape. 
     The first example method  260  an initial shape-determining step  262 , which involves determining or otherwise defining the predetermined shape. For example, with reference to  FIGS. 2A and 3A , the shape may be defined using the platen  44  of the cam plate  42  of  FIG. 2A ; the interior cutout of the template  76 ,  78  of  FIG. 3A , and so on. 
     Next, a pin-employing step  264  includes employing pins to selectively pull a fiber tow into the shape, including by moving the pins into positions defined by an outline of the shape as determined the shape-determining step  262 . Examples of pins in their terminal positions as defined by the shape outline include the positions of the pins  12 ,  14  in  FIG. 2E ; the positions of the pins  82 ,  84  in  FIG. 3D . 
     Subsequently, a fiber web-fixing step  266  includes binding adjacent portions of the fiber tow that extend across or over the shape, thereby resulting in a first ply of the predetermined shape. 
     Next, a ply-releasing releasing step  268  includes releasing the ply from contact with the pins. Mechanisms for cutting a ply loose from the pins and accompanying ply-forming apparatus include the shaped blades  56 ,  58  in  FIG. 2E , and the pin blades  112 ,  102  in  FIG. 3B . 
     Note that the method  260  of  FIG. 6  may be modified, without departing from the scope of the present teachings. For example, the method  260  may be further specify that the ply-releasing step  268  includes cutting the fiber tow loose from each pin using a blade. The blade can include a separate blade coupled to each pin. Alternatively, or in addition, a flexible (or otherwise shapeable) blade is arranged to or otherwise bent to conform to a path that is defined by the positions of the pins defined by an outline of the shape. 
     The first example method  260  of  FIG. 6  may further specify that the predetermined shape includes a three-dimensional shape and that a template is used to facilitate defining or otherwise specifying the shape. For example with reference to  FIG. 5A , the platen  220  may act as a template that is usable to define terminal positions of the pins  208 ,  218  as the pins  208 ,  218  extend to abut the platen  220 . In such case, the platen  220  includes outer edges that restrain or otherwise fix positions of the pins  208 ,  218  on opposite sides of the template  220 , such that the fiber tow drapes over (or otherwise conforms to a surface of) an external shape of (or an internal shape as with the templates  76 ,  78  of  FIG. 3C ). 
     Accordingly, the template may include a three-dimensional template (e.g., the platen  220  of  FIG. 5A ), and wherein the predetermined shape includes a three-dimensional shape, i.e., a shape with one or more curved surfaces. The three-dimensional template may be a heatable platen that is usable to thermally activate binder material included in the fiber tow, so as to implement the fiber fixing/binding step  266 . 
     The first example method  260  may further include an additional step for selectively rotating the three-dimensional template, wherein the rotation begins from a first orientation and rotates to a second orientation about a rotation axis. 
     After the rotation, a second ply can be created, wherein the second play also exhibits the predetermined shape. Fibers of the tow of the second ply are angled differently from fibers of the tow of the first ply depending upon the angle by which the three-dimensional template has been rotated between the first orientation and the second orientation. Examples of crisscrossed fibers of two stacked similarly-shaped plies are shown in  FIGS. 5B and 5C . 
     The example method  260  of  FIG. 6  may be further modified to specify that the determined shape includes plural sub-shapes that comprise shapes of a kit for a preform. Examples of a template with plural cutouts for an example kit are shown in  FIG. 3E , which includes cutouts  136 - 146 . 
     The template  120  of  FIG. 3E  is said to exhibit plural shapes, and the interior shapes of the cutouts  136 - 138  define or otherwise constrain terminal positions of the pins. Alternatively, or in addition, a platen with plural shapes is used instead of a template with plural cutouts, when creating multiple plies for a particular kit. The platen may both define the plural shapes and facilitate bonding the fiber tow. 
     The first example method  260  may further include drawing fiber from a supply of fiber along a fiber axis between two opposing sets of pins; moving the opposing pins across an initial center fiber axis to form a fiber web in the predetermined shape; and fixing the fiber web, using a binder material, so as to form a shaped ply characterized by the predetermined shape. 
     Note that method  260  may be virtually replaced with a different method, without departing from the scope of the present teachings. An alternative example method for forming a shaped ply of fibers includes drawing one or more fibers between opposing sets of pins along an initial fiber axis. The opposing sets of pins include a first set of movable first pins; and a second set of movable second pins. Pins of the first set of pins and pins of the second column of pins are movable laterally relative to the initial fiber axis. 
     The first pins are initially staggered relative to the second pins, such that the first pins can move past adjacent second pins and vice versa, when the first pins and/or second pins are moved laterally relative to the initial fiber axis. The alternative example method may further involve selectively moving the first pins and the second pins across the initial fiber axis, thereby pulling the one or more fibers into a web of a predetermined shape formed by resulting positions of the first pins and the second pins. Then, fibers of the fiber web are fixed, e.g., bonded before being cut loose from the accompanying apparatus. 
     The opposing sets of pins initially include opposing columns of pins. The first set of movable pins initially includes a first column of the first pins. The second set of movable pins initially includes a second column of the second pins. 
       FIG. 7  is a flow diagram of a second example method  280  implementable via embodiments discussed herein. The second example method  280  facilitates fabricating shaped plies for composite structures. 
     A first step  284  involves—drawing the fiber from a fiber supply apparatus (e.g., including the spool  20  of  FIGS. 1A-1C ) under a predetermined tension along an initial fiber axis (e.g., the axis  50  of  FIGS. 1A-1C ) between a first set of fiber supports (e.g., pins) and a second set of fiber supports. 
     The first and second sets of fiber supports (also called support sets) may be initially positioned on opposite sides of the fiber axis. Each support (e.g., pin) of each set of fiber supports may also include a surface (e.g., a surface of the angled protrusion  190  of the pin of  FIG. 4D ) that engages with or otherwise comes in contact with the fiber, e.g., fiber tow, used to make plies in accordance with embodiments discussed herein. 
     A second step  284  includes moving the first and second sets of fiber supports (e.g., the first pins  12  and second pins  14  of  FIGS. 1A-2E ), via a motion mechanism, from their initial positions, across the fiber axis, to edge-defining positions (e.g., the terminal pin positions  12 ,  14  of  FIG. 2E ) corresponding with a desired ply shape, thereby forming a fiber web (e.g., the web  36  of  FIG. 1C ). 
     A third step  288  includes using a fiber web-fixing mechanism to form a shaped ply, e.g., by binding adjacent fiber courses in the fiber web via a binder or other glue mechanism. 
     Lastly, a fourth step  290  includes removing, via a release mechanism, the shaped ply from fiber engaging surfaces of the first and second sets of supports. 
     Note that the second example method  280  may be modified, without departing from the scope of the present teachings. For example, the method  280  may further specify that the first and second support sets comprise pins. The motion mechanism may include a mechanical template defining edge positions of (members, e.g., pins of) the first and second support sets. 
     The second example method may further include a template changing system or mechanism for installing any one of a plurality of mechanical templates in the system for use with the motion mechanism. The web fixing mechanism may include a platen adapted to compress and bond the fiber web. 
     The platen may melt a thermoplastic binder to bond the fiber web. Furthermore, the platen may be non-planer, e.g., it may be three-dimensional, such that it is not confined to a two-dimensional plane. 
       FIG. 8  is a general block diagram of an example computing system  1100  usable to control operation of embodiments discussed herein when the embodiments are automated and employ a computer system to run software for controlling actuators; picking and placing platens into devices; actuating pin plates; controlling tow tension, and so on, as needed for a given implementation. 
     Accordingly,  FIG. 8  illustrates a computer system suitable  1100  for controlling a system for forming shaped plies according to an embodiment of the invention. The computer system  1100  includes one or more general purpose or specialized processors  1105 , which can include microprocessors, microcontrollers, system on a chip (SoC) devices, digital signal processors, graphics processing units (GPUs), ASICs, and other information processing devices. The computer system  1100  also includes random access memory  1110  and non-volatile memory  1115 , such as a magnetic or optical disk drive and/or flash memory devices. 
     The computer system  1100  may optionally include one or more visual display devices  1120 . The computer system  1100  may also optionally include an audio processor  1125  for generating and receiving sound via speakers, microphone, or other audio inputs and outputs  1130 ; and optional sensors and input devices  1140 , such as keyboards; scroll wheels; buttons; keypads; touch pads, touch screens, and other touch sensors; joysticks and direction pads; motion sensors, such as accelerometers and gyroscopes; global positioning system (GPS) and other location determining sensors; temperature sensors; mechanical, optical, magnetic and/or other types of position detectors and/or limit switches for detecting the current positions of the various components of the above-described systems; voltage, current, resistance, capacitance, inductance, continuity, or any other type of sensor for measuring electrical characteristics of the various components of the above-described systems; force, acceleration, stress or strain, and/or tension sensors; and/or any other type of input device known in the art. Computer system  1100  may optionally include one or more cameras or other optical measurement devices  1135  for capturing still images and/or video. 
     The computer system  1100  may also include one or more modems and/or wired or wireless network interfaces  1145  (such as the 802.11 family of network standards) for communicating data via local-area networks  1150 ; wide-area networks such as the Internet; CDMA, GSM, or other cellular data networks of any generation or protocol; industrial networks; or any other standard or proprietary networks. The computer system  1100  can also include a peripheral and/or data transfer interface, such as wired or wireless USB, IEEE 1394 (Firewire), Bluetooth, or other wired or wireless data transfer interfaces. 
     The computer system  1100  can include a power system  1155  for obtaining electrical power from an external source, such as AC line current or DC power tailored to the computer system  1100  via an external power supply, as well as one or more rechargeable or one-time use batteries, fuel cells, or any other electrical energy generation device. Additionally, a power system  1155  may provide energy in the form of compressed gas, vacuum, and/or hydraulic systems to power various actuators and components of embodiments of the invention. 
     Computer system  1100  may be implemented in a variety of different form factors, including desktop and laptop configurations as well as embedded and headless forms. 
     Embodiments of the invention may use a variety of motors and actuators, such as brushed or brushless DC motors, AC synchronous and induction motors, stepper motors, servomotors, solenoids, and/or pneumatic and hydraulic actuators. In an embodiment, the computer system  1100  includes motor and actuator controls  1060  for providing power and control signals to these motors and actuators. 
     Further embodiments can be envisioned to one of ordinary skill in the art. In other embodiments, combinations or sub-combinations of the above disclosed invention can be advantageously made. The block diagrams of the architecture and flow charts are grouped for ease of understanding. However it should be understood that combinations of blocks, additions of new blocks, re-arrangement of blocks, and the like are contemplated in alternative embodiments of the present invention. 
     The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the claims. 
     Accordingly, although the description has been described with respect to particular embodiments thereof, these particular embodiments are merely illustrative, and not restrictive. For example, although fiber has been described in some embodiments as placed in an initial state “along an axis” other types of initial placement of one or more fiber strands may be employed, such as multiple fiber strands, one or more fibers not along a common axis, etc. Also, it may be desirable in some embodiments to use different tensioning approaches and even to employ “negative” tensioning or active feeding of the fiber or tow. Other variations from the embodiments described herein are possible. 
     It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. It is also within the spirit and scope to implement a program or code that can be stored in a machine-readable medium to permit a computer to perform any of the methods described above. 
     As used in the description herein and throughout the claims that follow, “a”, “an”, and “the” includes plural references unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. 
     Thus, while particular embodiments have been described herein, latitudes of modification, various changes, and substitutions are intended in the foregoing disclosures, and it will be appreciated that in some instances some features of particular embodiments will be employed without a corresponding use of other features without departing from the scope and spirit as set forth. Therefore, many modifications may be made to adapt a particular situation or material to the essential scope and spirit.