Patent Publication Number: US-10773464-B2

Title: Method for manufacturing composite airfoils

Description:
FIELD 
     The present disclosure relates in general to methods and apparatuses of manufacturing composite structures. The present disclosure relates more specifically to methods and apparatuses for manufacturing composite airfoils. 
     BACKGROUND 
     Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known foil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid. 
     The rotor blades generally include a suction side shell and a pressure side shell typically formed using molding processes that are bonded together at bond lines along the leading and trailing edges of the blade. Further, the pressure and suction shells are relatively lightweight and have structural properties (e.g., stiffness, buckling resistance and strength) which are not configured to withstand the bending moments and other loads exerted on the rotor blade during operation. Thus, to increase the stiffness, buckling resistance and strength of the rotor blade, the body shell is typically reinforced using one or more structural components (e.g. opposing spar caps with a shear web configured therebetween) that engage the inner pressure and suction side surfaces of the shell halves. 
     The spar caps are typically constructed of various materials, including but not limited to glass fiber laminate composites and/or carbon fiber laminate composites. The shell of the rotor blade is generally built around the spar caps of the blade by stacking layers of fiber fabrics in a shell mold. The layers are then typically infused together, e.g. with a thermoset resin. Accordingly, conventional rotor blades generally have a sandwich panel configuration. As such, conventional blade manufacturing of large rotor blades involves high labor costs, slow through put, and low utilization of expensive mold tooling. Further, the blade molds can be expensive to customize. 
     Thus, methods for manufacturing rotor blades may include forming the rotor blades in segments. The blade segments may then be assembled to form the rotor blade. For example, some modern rotor blades, such as those blades described in U.S. patent application Ser. No. 14/753,137 filed Jun. 29, 2015 and entitled “Modular Wind Turbine Rotor Blades and Methods of Assembling Same,” which is incorporated herein by reference in its entirety, have a modular panel configuration. Thus, the various blade components of the modular blade can be constructed of varying materials based on the function and/or location of the blade component. 
     In view of the foregoing, the art is continually seeking improved methods for manufacturing wind turbine rotor blade panels having printed grid structures. 
     BRIEF DESCRIPTION 
     Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
     One aspect of the present disclosure is directed to an apparatus for manufacturing a composite component. The apparatus includes a mold onto which the composite component is formed. The mold is disposed within a grid defined by a first axis and a second axis. The apparatus further includes a first frame assembly disposed above the mold and a plurality of machine heads coupled to the first frame assembly within the grid in an adjacent arrangement along the first axis. At least one of the mold or the plurality of machine heads is moveable along the first axis, the second axis, or both. At least one of the machine heads of the plurality of machine heads is moveable independently of one another along a third axis. A second frame assembly is moveable above the mold along the first axis, the second axis, or both. The second frame assembly includes a holding device. The holding device affixes to and releases from an outer skin to place and displace the outer skin at the mold. 
     In one embodiment, the holding device is moveable along the third axis to at least above the first frame assembly. In another embodiment, the holding device defines a vacuum tool configured to affix to and release from the outer skin via a vacuum applied to the outer skin. 
     In still another embodiment, the plurality of machine heads defines a front head and a rear head along the first axis substantially corresponding to a length of the composite component to be printed. At least one of the mold or the plurality of machine heads is moveable to dispose at least the front head along the first axis at or beyond the length of the composite component to be formed along a first direction corresponding to the first axis. At least one of the mold or the plurality of machine heads is moveable to dispose at least the rear head along the first axis at or beyond the length of the composite component to be formed along a second direction opposite of the first direction. 
     In still yet another embodiment, the plurality of machine heads defines a front head and a rear head along the first axis substantially corresponding to a width of the composite component to be printed. At least one of the mold or the plurality of machine heads is moveable to dispose at least the front head along the first axis at or beyond the width of the composite component to be formed along a first direction. At least one of the mold or the plurality of machine heads is moveable to dispose at least the rear head along the first axis at or beyond the width of the composite component to be formed along a second direction opposite of the first direction. 
     The present disclosure is further directed to a method of manufacturing a composite component. The method includes placing one or more fiber-reinforced outer skins on a mold via a holding device moveable along one or more of a first axis, a second axis, and a third axis; applying pressure onto the outer skin and the mold to seal at least a perimeter of the outer skin onto the mold; forming a plurality of rib members that intersect at a plurality of nodes to form at least one three-dimensional (3-D) reinforcement grid structure onto an inner surface of the one or more fiber-reinforced outer skins, wherein the grid structure bonds to the one or more fiber-reinforced outer skins as the grid structure is being deposited; and heating at least a portion of the fiber-reinforced outer skin to at least a first temperature threshold. 
     In one embodiment, the method further includes applying, via the holding device, heat to at least a portion of the fiber-reinforced outer skin. In various embodiments, applying pressure onto the outer skin includes pulling the outer skin onto the mold via a vacuum applied through a surface of the mold, through the outer skin, or both. In one embodiment, applying pressure onto the outer skin includes pressing the outer skin onto the mold at least along the third axis via the holding device. 
     In one embodiment of the method, the plurality of rib structures includes, at least, a first rib structure extending in a first direction and a second rib structure extending in a different, second direction, at least one of the first rib member or the second rib member having a varying height along a length thereof. 
     In another embodiment, forming the plurality of rib members includes printing and depositing the grid structure via a material deposition tool. 
     In still another embodiment, forming the plurality of rib members includes applying a composite fiber tape onto the inner surface of the outer skin via a tape deposition tool. 
     In one embodiment, the method further includes translating, via a first frame assembly, a plurality of machine heads along the first axis, the second axis, or the third axis proximate to the outer skin. 
     In another embodiment, the method further includes translating, via a second frame assembly, the holding device along the first axis, the second axis, or the third axis. 
     In yet another embodiment of the method, forming the plurality of rib structures is via a plurality of machine heads arranged along at least one of the first axis or the second axis, and wherein at least one of the plurality of machine heads is independently moveable along the third axis. 
     In still yet another embodiment of the method, the first temperature threshold corresponds to a temperature at least approximately between a glass transition temperature and a melting temperature of a resin in the outer skin. 
     Another aspect of the present disclosure is directed to a method of manufacturing a plurality of composite components. The method includes placing a first fiber-reinforced outer skin onto a first mold via a holding device moveable along one or more of a first axis, a second axis, and a third axis; applying pressure onto the first outer skin and the first mold to seal at least a perimeter of the first outer skin onto the first mold; forming a plurality of rib members that intersect at a plurality of nodes to form at least one three-dimensional (3-D) reinforcement grid structure onto an inner surface of the one or more first fiber-reinforced outer skins, wherein the grid structure bonds to the one or more first fiber-reinforced outer skins as the grid structure is being deposited; heating at least a portion of the first fiber-reinforced outer skin to at least a first temperature threshold; placing a second fiber-reinforced outer skin onto a second mold via the holding device, wherein the second mold is disposed adjacent to the first mold; heating at least a portion of the second fiber-reinforced outer skin to at least a first temperature threshold; applying pressure onto the second outer skin and the second mold to seal at least a perimeter of the second outer skin onto the second mold; forming a plurality of rib members that intersect at a plurality of nodes to form at least one three-dimensional (3-D) reinforcement grid structure onto an inner surface of the one or more second fiber-reinforced outer skins, wherein the grid structure bonds to the one or more second fiber-reinforced outer skins as the grid structure is being deposited; and removing the first outer skin from the first mold via the holding device. 
     In one embodiment, the method further includes applying, via the holding device, heat to at least a portion of the second fiber-reinforced outer skin. In another embodiment, the method further includes translating, via a first frame assembly, a plurality of machine heads along one or more of the first axis, the second axis, or the third axis proximate to the first outer skin; and translating, via a second frame assembly, the holding device along one or more of the first axis, the second axis, or the third axis proximate to the second mold when the plurality of machine heads is proximate to the first outer skin at the first mold. In still yet another embodiment, the method further includes translating, via a first frame assembly, a plurality of machine heads along one or more of the first axis, the second axis, or the third axis proximate to the second outer skin; and translating, via a second frame assembly, the holding device along one or more of the first axis, the second axis, or the third axis proximate to the first mold when the plurality of machine heads is proximate to the second outer skin at the second mold. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
         FIG. 1  illustrates a perspective view of one embodiment of a wind turbine according to an aspect of the present disclosure; 
         FIG. 2  illustrates a perspective view of one embodiment of a composite component according to an aspect of the present disclosure; 
         FIG. 3  illustrates an exploded view of the composite component of  FIG. 2 ; 
         FIG. 4  illustrates a cross-sectional view of one embodiment of a leading edge segment of a composite component according to an aspect of the present disclosure; 
         FIG. 5  illustrates a cross-sectional view of one embodiment of a trailing edge segment of a composite component according to an aspect of the present disclosure; 
         FIG. 6  illustrates a cross-sectional view of the composite component of  FIG. 2  according to an aspect of the present disclosure along line  6 - 6 ; 
         FIG. 7  illustrates a cross-sectional view of the composite component of  FIG. 2  according to an aspect of the present disclosure along line  7 - 7 ; 
         FIG. 8A  illustrates a perspective view of one embodiment of an apparatus for manufacturing a composite component, such as the composite component generally illustrated in  FIGS. 2-7 ; 
         FIG. 8B  illustrates a perspective view of one embodiment of an apparatus for manufacturing a composite component, such as the composite component generally illustrated in  FIGS. 2-7 ; 
         FIG. 8C  illustrates a perspective view of one embodiment of an apparatus for manufacturing a composite component, such as the composite component generally illustrated in  FIGS. 2-7 ; 
         FIG. 8D  illustrates a perspective view of the embodiment generally provided in  FIG. 8C  in an open position of the apparatus for manufacturing a composite component; 
         FIG. 8E  illustrates a side view of a portion of an embodiment of the apparatus generally provided in regard to  FIGS. 8A-8F ; 
         FIG. 8F  illustrates a perspective view of the embodiments of the apparatus generally provided in  FIGS. 8C and 8D  further depicting additional embodiments of the apparatus; 
         FIG. 9A  illustrates a perspective view of another embodiment of an apparatus for manufacturing a composite component, such as the composite component generally illustrated in  FIGS. 2-7 ; 
         FIG. 9B  illustrates a perspective view of another embodiment of an apparatus for manufacturing a composite component, such as the composite component generally illustrated in  FIGS. 2-7   
         FIG. 10  illustrates a cross-sectional view of one embodiment of a mold of a composite component, particularly illustrating an outer skin placed in the mold with a plurality of grid structures printed thereto; 
         FIG. 11  illustrates a perspective view of one embodiment of a grid structure according to an aspect of the present disclosure; 
         FIG. 12  illustrates a perspective view of one embodiment of a mold of a composite component with an apparatus for manufacturing the composite component positioned above the mold so as to print a grid structure thereto according to an aspect of the present disclosure; 
         FIG. 13  illustrates a perspective view of one embodiment of a mold of a composite component with an apparatus for manufacturing a composite component positioned above the mold and printing an outline of a grid structure thereto according to an aspect of the present disclosure; 
         FIG. 14  illustrates a perspective view of one embodiment of a mold of a composite component with an apparatus for manufacturing a composite component positioned above the mold and printing an outline of a grid structure thereto according to an aspect of the present disclosure; 
         FIG. 15  illustrates a cross-sectional view of one embodiment of a first rib member of a grid structure according to an aspect of the present disclosure; 
         FIG. 16  illustrates a cross-sectional view of another embodiment of a first rib member of a grid structure according to an aspect of the present disclosure; 
         FIG. 17  illustrates a top view of one embodiment of a grid structure according to an aspect of the present disclosure; 
         FIG. 18  illustrates a cross-sectional view of one embodiment of a first rib member and intersecting second rib members of a grid structure according to an aspect of the present disclosure; 
         FIG. 19  illustrates a cross-sectional view of one embodiment of a second rib member of a grid structure according to an aspect of the present disclosure; 
         FIG. 20  illustrates a top view of one embodiment of a grid structure according to an aspect of the present disclosure, particularly illustrating rib members of the grid structure arranged in a random pattern; 
         FIG. 21  illustrates a perspective view of another embodiment of a grid structure according to an aspect of the present disclosure, particularly illustrating rib members of the grid structure arranged in a random pattern; 
         FIG. 22  illustrates a graph of one embodiment of buckling load factor (y-axis) versus weight ratio (x-axis) of a grid structure according to an aspect of the present disclosure; 
         FIG. 23  illustrates a partial, top view of one embodiment of a printed grid structure according to an aspect of the present disclosure, particularly illustrating a node of the grid structure; 
         FIG. 24  illustrates a partial, top view of one embodiment of a printed grid structure according to an aspect of the present disclosure, particularly illustrating a start printing location and an end printing location of the grid structure; 
         FIG. 25  illustrates an elevation view of one embodiment of a printed rib member of a grid structure according to an aspect of the present disclosure, particularly illustrating a base section of one of the rib members of the grid structure having a wider and thinner cross-section than the remainder of the rib member so as to improve bonding of the grid structure to the outer skins of the composite component; 
         FIG. 26  illustrates a top view of another embodiment of a grid structure according to an aspect of the present disclosure, particularly illustrating additional features printed to the grid structure; 
         FIG. 27  illustrates a cross-sectional view of one embodiment of a composite component having a printed grid structure arranged therein according to an aspect of the present disclosure, particularly illustrating alignment features printed to the grid structure for receiving the spar caps and shear web; 
         FIG. 28  illustrates a partial, cross-sectional view of the composite component of  FIG. 25 , particularly illustrating additional features printed to the grid structure for controlling adhesive squeeze out; 
         FIG. 29  illustrates a cross-sectional view of one embodiment of a composite component having printed grid structures arranged therein according to an aspect of the present disclosure, particularly illustrating male and female panel alignment features printed to the grid structure; 
         FIG. 30  illustrates a top view of yet another embodiment of a grid structure according to an aspect of the present disclosure, particularly illustrating auxiliary features printed to the grid structure; 
         FIG. 31  illustrates a cross-sectional view of one embodiment of a composite component according to an aspect of the present disclosure, particularly illustrating a plurality of grid structures printed to inner surfaces of the rotor blade panel; and 
         FIG. 32  illustrates a partial, cross-sectional view of the leading edge of the composite component of  FIG. 29 , particularly illustrating a plurality of adhesive gaps. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
     Generally, the present disclosure is directed to an apparatus and method for manufacturing a composite component, including structures thereof, using automated deposition of materials via technologies such as 3-D Printing, additive manufacturing, automated fiber deposition or tape deposition, as well as other techniques that utilize CNC control and multiple degrees of freedom to deposit material. The apparatus generally includes a mold onto which the composite component is formed. The mold is disposed within a grid defined by a first axis and a second axis generally perpendicular to the first axis. A plurality of machine heads is disposed within the grid in adjacent arrangement along the first axis. The plurality of machine heads is coupled to a first frame assembly. The mold, the plurality of machine heads, or both, is moveable along the first axis and the second axis. Each machine head of the plurality of machine heads is moveable independently of one another along a third axis. 
     The embodiments of the apparatus and method shown and described herein may improve manufacturing cycle time efficiency, such as by enabling a relatively simple zig-zag, sinusoidal, or orthogonal motion to deposit composite component structures, such as onto a rotor blade panel formed onto a mold. Thus, the methods described herein provide many advantages not present in the prior art. For example, the methods of the present disclosure may provide the ability to easily customize composite component structures having various curvatures, aerodynamic characteristics, strengths, stiffness, etc. For example, the printed or formed structures of the present disclosure can be designed to match the stiffness and/or buckling resistance of existing sandwich panels for composite components. More specifically, composite components defining the exemplary rotor blades and components thereof generally provided in the present disclosure can be more easily customized based on the local buckling resistance needed. Still further advantages include the ability to locally and temporarily buckle to reduce loads and/or tune the resonant frequency of the rotor blades to avoid problem frequencies. Moreover, the structures described herein enable bend-twist coupling of the composite component, such as defining a rotor blade. Furthermore, improved methods of manufacturing, and improve manufacturing cycle time associated therewith, for the improved customized composite component structures may thereby enable cost-efficient production and availability of composite components, including, but not limited to, rotor blades described herein, such as through a higher level of automation, faster throughput, and reduced tooling costs and/or higher tooling utilization. Further, the composite components of the present disclosure may not require adhesives, especially those produced with thermoplastic materials, thereby eliminating cost, quality issues, and extra weight associated with bond paste. 
     Referring now to the drawings,  FIG. 1  illustrates one embodiment of a wind turbine  10  according to the present disclosure. As shown, the wind turbine  10  includes a tower  12  with a nacelle  14  mounted thereon. A plurality of rotor blades  16  are mounted to a rotor hub  18 , which is in turn connected to a main flange that turns a main rotor shaft. The wind turbine power generation and control components are housed within the nacelle  14 . The view of  FIG. 1  is provided for illustrative purposes only to place the present invention in an exemplary field of use. It should be appreciated that the invention is not limited to wind turbines or any particular type of wind turbine configuration. In addition, the present invention is not limited to use with wind turbines, but may be utilized in producing any composite component, such as any application having rotor blades. Further, the methods described herein may also apply to manufacturing any composite component that benefits from printing or laying a structure to a mold. Still further, the methods described herein may further apply to manufacturing any composite component that benefits from printing or laying a structure onto a skin placed onto a mold, which may include, but is not limited to, before the skins have cooled so as to take advantage of the heat from the skins to provide adequate bonding between the printed structure and the skins. As such, the need for additional adhesive or additional curing is eliminated. 
     Referring now to  FIGS. 2 and 3 , various views of an exemplary composite component that may be produced by the structures, apparatuses, and methods generally provided herein according to the present disclosure are illustrated. More specifically, an exemplary embodiment of a composite component defining a rotor blade  16  is generally provided. As shown, the illustrated rotor blade  16  has a segmented or modular configuration. It should also be understood that the rotor blade  16  may include any other suitable configuration now known or later developed in the art. As shown, the modular rotor blade  16  includes a main blade structure  15  constructed, at least in part, from a thermoset and/or a thermoplastic material and at least one blade segment  21  configured with the main blade structure  15 . More specifically, as shown, the rotor blade  16  includes a plurality of blade segments  21 . The blade segment(s)  21  may also be constructed, at least in part, from a thermoset and/or a thermoplastic material. 
     The thermoplastic rotor blade components and/or materials as described herein generally encompass a plastic material or polymer that is reversible in nature. For example, thermoplastic materials typically become pliable or moldable when heated to a certain temperature and returns to a more rigid state upon cooling. Further, thermoplastic materials may include amorphous thermoplastic materials and/or semi-crystalline thermoplastic materials. For example, some amorphous thermoplastic materials may generally include, but are not limited to, styrenes, vinyls, cellulosics, polyesters, acrylics, polysulphones, and/or imides. More specifically, exemplary amorphous thermoplastic materials may include polystyrene, acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), glycolised polyethylene terephthalate (PET-G), polycarbonate, polyvinyl acetate, amorphous polyamide, polyvinyl chlorides (PVC), polyvinylidene chloride, polyurethane, or any other suitable amorphous thermoplastic material. In addition, exemplary semi-crystalline thermoplastic materials may generally include, but are not limited to polyolefins, polyamides, fluoropolymer, ethyl-methyl acrylate, polyesters, polycarbonates, and/or acetals. More specifically, exemplary semi-crystalline thermoplastic materials may include polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene, polyphenyl sulfide, polyethylene, polyamide (nylon), polyetherketone, or any other suitable semi-crystalline thermoplastic material. 
     Further, the thermoset components and/or materials as described herein generally encompass a plastic material or polymer that is non-reversible in nature. For example, thermoset materials, once cured, cannot be easily remolded or returned to a liquid state. As such, after initial forming, thermoset materials are generally resistant to heat, corrosion, and/or creep. Example thermoset materials may generally include, but are not limited to, some polyesters, some polyurethanes, esters, epoxies, or any other suitable thermoset material. 
     In addition, as mentioned, the thermoplastic and/or the thermoset material as described herein may optionally be reinforced with a fiber material, including but not limited to glass fibers, carbon fibers, polymer fibers, wood fibers, bamboo fibers, ceramic fibers, nanofibers, metal fibers, or similar or combinations thereof. In addition, the direction of the fibers may include multi-axial, unidirectional, biaxial, triaxial, or any other another suitable direction and/or combinations thereof. Further, the fiber content may vary depending on the stiffness required in the corresponding blade component, the region or location of the blade component in the rotor blade  16 , and/or the desired weldability of the component. 
     More specifically, as shown, the main blade structure  15  may include any one of or a combination of the following: a pre-formed blade root section  20 , a pre-formed blade tip section  22 , one or more one or more continuous spar caps  48 ,  50 ,  51 ,  53 , one or more shear webs  35  ( FIGS. 6-7 ), an additional structural component  52  secured to the blade root section  20 , and/or any other suitable structural component of the rotor blade  16 . Further, the blade root section  20  is configured to be mounted or otherwise secured to the rotor  18  ( FIG. 1 ). In addition, as shown in  FIG. 2 , the rotor blade  16  defines a length or span  23  that is equal to the total length between the blade root section  20  and the blade tip section  22 . As shown in  FIGS. 2 and 6 , the rotor blade  16  also defines a width or chord  25  that is equal to the total length between a leading edge  24  of the rotor blade  16  and a trailing edge  26  of the rotor blade  16 . As is generally understood, the width or chord  25  may generally vary in length with respect to the length or span  23  as the rotor blade  16  extends from the blade root section  20  to the blade tip section  22 . 
     Referring particularly to  FIGS. 2-4 , any number of blade segments  21  or panels having any suitable size and/or shape may be generally arranged between the blade root section  20  and the blade tip section  22  along a longitudinal axis  27  in a generally span-wise direction. Thus, the blade segments  21  generally serve as the outer casing/covering of the rotor blade  16  and may define a substantially aerodynamic profile, such as by defining a symmetrical or cambered airfoil-shaped cross-section. In additional embodiments, it should be understood that the blade segment portion of the blade  16  may include any combination of the segments described herein and are not limited to the embodiment as depicted. In addition, the blade segments  21  may be constructed of any suitable materials, including but not limited to a thermoset material or a thermoplastic material optionally reinforced with one or more fiber materials. More specifically, in certain embodiments, the blade panels  21  may include any one of or combination of the following: pressure and/or suction side segments  44 ,  46 , ( FIGS. 2 and 3 ), leading and/or trailing edge segments  40 ,  42  ( FIGS. 2-6 ), a non-jointed segment, a single-jointed segment, a multi-jointed blade segment, a J-shaped blade segment, or similar. 
     More specifically, as shown in  FIG. 4 , the leading edge segments  40  may have a forward pressure side surface  28  and a forward suction side surface  30 . Similarly, as shown in  FIG. 5 , each of the trailing edge segments  42  may have an aft pressure side surface  32  and an aft suction side surface  34 . Thus, the forward pressure side surface  28  of the leading edge segment  40  and the aft pressure side surface  32  of the trailing edge segment  42  generally define a pressure side surface of the rotor blade  16 . Similarly, the forward suction side surface  30  of the leading edge segment  40  and the aft suction side surface  34  of the trailing edge segment  42  generally define a suction side surface of the rotor blade  16 . In addition, as particularly shown in  FIG. 6 , the leading edge segment(s)  40  and the trailing edge segment(s)  42  may be joined at a pressure side seam  36  and a suction side seam  38 . For example, the blade segments  40 ,  42  may be configured to overlap at the pressure side seam  36  and/or the suction side seam  38 . Further, as shown in  FIG. 2 , adjacent blade segments  21  may be configured to overlap at a seam  54 . Thus, where the blade segments  21  are constructed at least partially of a thermoplastic material, adjacent blade segments  21  can be welded together along the seams  36 ,  38 ,  54 , which will be discussed in more detail herein. Alternatively, in certain embodiments, the various segments of the rotor blade  16  may be secured together via an adhesive (or mechanical fasteners) configured between the overlapping leading and trailing edge segments  40 ,  42  and/or the overlapping adjacent leading or trailing edge segments  40 ,  42 . 
     In specific embodiments, as shown in  FIGS. 2-3 and 6-7 , the blade root section  20  may include one or more longitudinally extending spar caps  48 ,  50  infused therewith. For example, the blade root section  20  may be configured according to U.S. application Ser. No. 14/753,155 filed Jun. 29, 2015 entitled “Blade Root Section for a Modular Rotor Blade and Method of Manufacturing Same” which is incorporated herein by reference in its entirety. 
     Similarly, the blade tip section  22  may include one or more longitudinally extending spar caps  51 ,  53  infused therewith. More specifically, as shown, the spar caps  48 ,  50 ,  51 ,  53  may be configured to be engaged against opposing inner surfaces of the blade segments  21  of the rotor blade  16 . Further, the blade root spar caps  48 ,  50  may be configured to align with the blade tip spar caps  51 ,  53 . Thus, the spar caps  48 ,  50 ,  51 ,  53  may generally be designed to control the bending stresses and/or other loads acting on the rotor blade  16  in a generally span-wise direction (a direction parallel to the length or span  23  of the rotor blade  16 ) during operation of a wind turbine  10 . In addition, the spar caps  48 ,  50 ,  51 ,  53  may be designed to withstand the span-wise compression occurring during operation of the wind turbine  10 . Further, the spar cap(s)  48 ,  50 ,  51 ,  53  may be configured to extend from the blade root section  20  to the blade tip section  22  or a portion thereof. Thus, in certain embodiments, the blade root section  20  and the blade tip section  22  may be joined together via their respective spar caps  48 ,  50 ,  51 ,  53 . 
     In addition, the spar caps  48 ,  50 ,  51 ,  53  may be constructed of any suitable materials, e.g. a thermoplastic or thermoset material or combinations thereof. Further, the spar caps  48 ,  50 ,  51 ,  53  may be pultruded from thermoplastic or thermoset resins. As used herein, the terms “pultruded,” “pultrusions,” or similar generally encompass reinforced materials (e.g. fibers or woven or braided strands) that are impregnated with a resin and pulled through a stationary die such that the resin cures, solidifies, or undergoes polymerization. As such, the process of manufacturing pultruded members is typically characterized by a continuous process of composite materials that produces composite parts having a constant cross-section. Thus, the pre-cured composite materials may include pultrusions constructed of reinforced thermoset or thermoplastic materials. Further, the spar caps  48 ,  50 ,  51 ,  53  may be formed of the same pre-cured composites or different pre-cured composites. In addition, the pultruded components may be produced from rovings, which generally encompass long and narrow bundles of fibers that are not combined until joined by a cured resin. 
     Referring to  FIGS. 6-7 , one or more shear webs  35  may be configured between the one or more spar caps  48 ,  50 ,  51 ,  53 . More particularly, the shear web(s)  35  may be configured to increase the rigidity in the blade root section  20  and/or the blade tip section  22 . Further, the shear web(s)  35  may be configured to close out the blade root section  20 . 
     In addition, as shown in  FIGS. 2 and 3 , the additional structural component  52  may be secured to the blade root section  20  and extend in a generally span-wise direction so as to provide further support to the rotor blade  16 . For example, the structural component  52  may be configured according to U.S. application Ser. No. 14/753,150 filed Jun. 29, 2015 entitled “Structural Component for a Modular Rotor Blade” which is incorporated herein by reference in its entirety. More specifically, the structural component  52  may extend any suitable distance between the blade root section  20  and the blade tip section  22 . Thus, the structural component  52  is configured to provide additional structural support for the rotor blade  16  as well as an optional mounting structure for the various blade segments  21  as described herein. For example, in certain embodiments, the structural component  52  may be secured to the blade root section  20  and may extend a predetermined span-wise distance such that the leading and/or trailing edge segments  40 ,  42  can be mounted thereto. 
     Referring now to  FIGS. 8A-8F  and  FIGS. 9A-9B , the present disclosure is directed to embodiments of an apparatus  200  and methods of manufacturing composite components  210 , such as rotor blade panels  21  having at least one printed reinforcement grid structure  62  formed via 3-D printing (e.g., blade segments illustrated in regard to  FIGS. 2-7 ). As such, in certain embodiments, the composite component  210  may include the rotor blade panel  21  further including a pressure side surface, a suction side surface, a trailing edge segment, a leading edge segment, or combinations thereof 3-D printing, as used herein, is generally understood to encompass processes used to synthesize three-dimensional objects in which successive layers of material are formed under computer control to create the objects. As such, composite components  210  of almost any size and/or shape can be produced from digital model data. It should further be understood that the methods of the present disclosure are not limited to 3-D printing, but rather, may also encompass more than three degrees of freedom such that the printing techniques are not limited to printing stacked two-dimensional layers, but are also capable of printing curved shapes. 
     Referring now to  FIGS. 8A-8F , an apparatus  200  for manufacturing a composite component  205  is generally provided. The composite component  210  may generally define all or part of the rotor blade  16  or rotor blade panel  21  such as described in regard to  FIGS. 2-7 . The apparatus  200  includes a mold  58  onto which the composite component  210  is formed. The mold  58  is disposed within a grid  205  defined by a first axis  201  and a second axis  202  generally perpendicular to the first axis  201 . A plurality of machine heads  220  disposed within the grid  205  in adjacent arrangement along the first axis  201  or the second axis  202 . The plurality of machine heads  220  is coupled to a first frame assembly  230  above the mold  58 . The mold  58 , the plurality of machine heads  220 , or both, is moveable along the first axis  201  and the second axis  202 . Each machine head  225  of the plurality of machine heads  220  is moveable independently of one another along a third axis  203 . 
     In the embodiment generally provided in  FIGS. 8A and 8B , each machine head  225  of the plurality of machine heads  220  is disposed in an adjacent arrangement along the first axis  201 . The first axis  201  may generally correspond to at least a length or span  23  ( FIG. 2 ) of the composite component  210 , such as embodiments of the rotor blade  16  or rotor blade panel  21  described in regard to  FIGS. 2-7 . For example, the first axis  201  may be substantially parallel to the span  23  ( FIG. 2 ) of the rotor blade panel  21 . In one embodiment, the first axis  201  is approximately parallel, plus or minus 10%, of the first axis  201 . 
     The second axis  202  may generally correspond to at least a width or chord  25  ( FIG. 2 ) of the composite component  210 , such as embodiments of the rotor blade  16  or rotor blade panel  21  described in regard to  FIGS. 2-7 . For example, the second axis  202  may be substantially parallel to the width or chord  25  ( FIG. 2 ) of the rotor blade panel  21 . The width or chord  25  of the composite component  210  is generally perpendicular to the length or span  23  of the composite component  210 . In one embodiment, the second axis  202  is approximately parallel, plus or minus 10% of the second axis  202 . 
     In various embodiments, the first frame assembly  230  may generally define a gantry system such as to articulate the plurality of machine heads  220  along the first axis  201  and the second axis  202 . In various embodiments, the plurality of machine heads  220  defines a front head  221  and a rear head  222  along the first axis  201 . In one embodiment, the plurality of machine heads  220  is arranged along the first axis  201  at least approximately 50% or greater of the length  23  of the composite component  210  to be formed by the apparatus  200 . In still other embodiments, the plurality of machine heads  220  is arranged along the first axis  201  at least approximately 70% or greater of the length  23  of the composite component  210  to be formed by the apparatus  200 . In still yet other embodiments, the plurality of machine heads  220  is arranged along the first axis  201  at least approximately 100% or greater of the length  23  of the composite component  210  to be formed by the apparatus  200 . In various embodiments (e.g.,  FIG. 8A ), the plurality of machine heads  220  may extend at least the entire length or span  23 , or greater, of the mold  58  or composite component  210  to be formed. 
     In the embodiment generally provided in  FIGS. 8A through 8D , at least the mold  58  or the plurality of machine heads  220  is moveable to dispose (e.g., position, place, or arrange) at least the front head  221  along the first axis  201  beyond the length or span  23  of the composite component  210  along a first direction  211 . Furthermore, the mold  58 , the plurality of machine heads  220 , or both, is moveable to dispose at least the rear head  222  along the first axis  201  beyond the length or span  23  ( FIG. 2 ) of the composite component  210  (e.g., defining the rotor blade panel  21 ) along a second direction  212  opposite of the first direction  211 . 
     Referring now to the embodiment generally provided in  FIG. 8B , at least a portion of the first frame assembly  230  may be moveable along the second axis  202  greater than the width or chord  25  of the composite component  210 , such as defining the rotor blade panel  21 . For example, the plurality of machine heads  220  may be moveable greater than the width or chord  25  of a first composite component  213 . The plurality of machine heads  220  may be disposed over a second composite component  214  disposed adjacent to the first composite component  213  along the second axis  202 . As such, the apparatus  200  may enable the plurality of machine heads  220  to proceed to print and deposit one or more rib structures  64  ( FIGS. 10-32 ) the second composite component  214  while the rib structures  64  at first composite component  213  solidify or cure upon the outer skin  56 . In various embodiments, a second frame  232  of the first frame assembly  230  is moveable to place, position, or otherwise dispose the plurality of machine heads  220  at least equal to or greater than the width or chord  25  of the composite component  210 . 
     Referring now to the embodiment generally provided in  FIG. 8B , the first frame assembly  230  may further define a supporting member  236  extended along the second axis  202 . The supporting member  236  may generally define a portion of the first frame assembly  230  such as to provide structural support to the plurality of machine heads  220 . For example, the supporting member  236  may mitigate curvature or sagging of the plurality of machine heads  220  across the spanwise adjacent arrangement. The supporting member  236  may generally partition the plurality of machine heads  236  into a plurality of the plurality of machine heads  236 , such as each are supported to a separate or independently moveable second frame  232 , such as further described below. 
     Referring now to  FIGS. 8A-8E , the first frame assembly  230  may include a first frame  231  movable along the first axis  201  and a second frame  232  coupled to the first frame  231 . The first frame  231  may generally be coupled to a base frame  235  permitting articulation or movement along the first axis  201 . The base frame  235  may generally define a rail assembly, track structure, glide, automated guide vehicle (AGV), or other configuration enabling the first frame  231  to move along the first axis  201 . In the embodiment generally provided in  FIG. 8A , the plurality of machine heads  220  is moveably coupled to the second frame  232  such that the plurality of machine heads  220  is moveable generally in unison along the first axis  201 , the second axis  202 , or both. As described in regard to  FIG. 8B , the second frame  232  may be moveable along the second axis  202  such as to place, position, arrange, or otherwise dispose the plurality of machine heads  220  at least along the entire width or chord  25  of the composite component  210 . Still further, the second frame  232  may be moveable along the second axis  202  such as to dispose the plurality of machine heads  220  proximate to the second composite component  214  (e.g., vertically over the second composite component  214  along the third axis  203 ). 
     The second frame  231  further enables movement of at least one machine head  225  along the third axis  203  independent of another machine head  225 . The third axis  203  generally corresponds to a vertical distance over the grid  205 . More specifically, the third axis  203  corresponds to a vertical distance over the rotor blade panel  21 . As such, each machine head  225  of the plurality of machine heads  220  is moveable independently of one another along the third axis  203  to independently define a vertical distance over the grid  205 , or more specifically, the rotor blade panel  21 . 
     Referring now to the embodiments generally provided in  FIGS. 8C and 8D , a plurality of the first frame  231  may be disposed on the base frame  235 . Each first frame  231  may be independently moveable on the base frame  235 . For example, each first frame  231  may be independently moveable along the first axis  201 . In various embodiments, each first frame  231  may be independently moveable along the first axis  201  in opposite directions (e.g., one or more first frames  231  toward the first direction  211  and another or more first frames  231  toward the second direction  212 ). 
     As another example, in reference to the embodiment generally provided in  FIGS. 8C and 8D , the first frame  231  may further displace along the first axis  201  such as to provide vertical clearance along the third axis  203  relative to one or more of the composite components  210 . In various embodiments, the first frame assembly  230  defines a plurality of the first frame  231  to which one or more of the second frame  232  is attached to each of the first frame  231 . For example, referring to  FIG. 8C , one of the first frame  231   a  may translate or move along the first axis  201  on the base frame  235  to position the plurality of machine heads  220  and the first frame  231   a  away from one or more of the composite components  210 , such as generally depicted at the first frame  231   b  in  FIG. 8D . 
     For example, the first frame assembly  230  may displace, translate, or otherwise move to apply the outer skin  56  onto the mold  58 , and for removing the composite component  210  such as the rotor blade panel  21  from the mold  58  at least partially along the third axis  203 . As another example, one or more of the first frame  231  of the first frame assembly  230 , such as the first frame  231   a  depicted in  FIG. 8C , may translate such as depicted at the first frame  231   b  in  FIG. 8D , to enable movement of another first frame  231 , such as depicted at  231   c  in  FIG. 8D , to translate along the first axis  201 . In various embodiments, the plurality of machine heads  220  at one of more of the first frame  231  (e.g.,  231   a ,  231   b ,  231   c ) may define varying combinations of machine heads  225  such that one first frame  231  (e.g.,  231   c ) may translate over one or more molds  58  to perform a function specific to one first frame  231  in contrast to another first frame  231  (e.g.,  231   a ,  231   b ). Referring now to  FIGS. 9A and 9B , further exemplary embodiments of the apparatus  200  are generally provided. The embodiments generally provided in  FIGS. 9A and 9B  may be configured substantially similarly as shown and described in regard to  FIGS. 8A, 8B, 8C, and 8D . In the embodiments generally provided in  FIGS. 9A and 9B , the first axis  201  may generally correspond to a width or chord  25  ( FIG. 2 ) of composite component  210  and the second axis  202  may generally correspond to a length or span  23  ( FIG. 2 ) of the composite component  210 . For example, in various embodiments, the first axis  201  is substantially parallel to at least a width or chord  25  ( FIG. 2 ) of the rotor blade panel  21 . The second axis  202  is substantially parallel to at least a length or span  23  ( FIG. 2 ) of the rotor blade panel  21 . In one embodiment, the mold  58 , the plurality of machine heads  220 , or both, is moveable to dispose at least the front head  221  along the first axis  201  greater than the width or chord  25  of the rotor blade panel  21  along the first direction  211 . 
     In the embodiment generally provided in  FIGS. 9A and 9B , the mold  58 , the plurality of machine heads  220 , or both, is moveable to dispose at least the rear head  222  along the first axis  201  beyond the width or chord  25  ( FIG. 2 ) of the rotor blade panel  21  along a second direction  212 . As such, the plurality of machine heads  220  occupies at least the entire length or span  23  of the rotor blade panel  21  to deposit materials for one or more structures of the rotor blade panel  21  such as described in regard to  FIGS. 2-7 . Still further, the plurality of machine heads  220  is moveable to provide vertical clearance over the mold  58 , the rotor blade panel  21 , or both to enable access to the mold  58  and/or the rotor blade panel  21  from at least partially along the third axis  203 . 
     Referring still to the exemplary embodiments generally provided in  FIGS. 8A, 8B, 8C, 8D, 8E, 9A, and 9B , the apparatus  200  may further define a fourth axis  204 . The fourth axis  204  is generally defined at the plurality of machine heads  220 . For example, referring more specifically to the embodiment generally provided in  FIG. 8E , the fourth axis  204  is generally defined by the axis upon which the plurality of machine heads  220  is arranged (e.g., the first axis  201  shown in  FIGS. 8A-8D ) and a vertical distance along the third axis  203 . The fourth axis  204  generally defines an axis about which one or more of the machine heads  225  may rotate or pivot independently of one another. For example, each machine head  225  generally defines a working end  227  proximate to the composite component  210  (e.g., a grid structure  62  of the rotor blade panel  21 ). The plurality of machine heads  220  is configured to dispose the working end  227  of one or more of the machine heads  225  at an angle  228  relative to the grid  205 , the mold  58 , or both. 
     In various embodiments, the apparatus  200 , such as at the second frame  232 , at the plurality of machine heads  220 , or both, is configured to move or pivot along the fourth axis  204  to dispose the working end  227  of one or more machine heads  225  at an angle relative to the grid  205  between approximately 0 degrees and approximately 175 degrees. 
     Referring still to  FIG. 8E , in another embodiment, the apparatus  200  may further define a fifth axis  206  around which one or more of the machine heads  225  may rotate. The fifth axis  206  is generally defined perpendicular to the fourth axis  204  and the second axis  202 . The fifth axis  206  is further generally defined through each machine head  225  such as to define a machine head centerline axis, such as generally depicted in  FIG. 8A . In one embodiment, the machine head  225  may rotate approximately 360 degrees around the fifth axis  206 . More specifically, the working end  227  of each machine head  225  may rotate approximately 360 degrees around the fifth axis  206 . 
     Referring back to  FIG. 8A , each machine head  225  may define the machine head centerline axis  226  at least partially along third axis  203 . Each adjacent pair of centerline axes  226 ,  226   a  may define a distance  224  corresponding to a desired spacing of a structure of the composite component  210  to be formed onto the mold  58 . In various embodiments, the center to center distance  224  of each machine head  225  may generally correspond to a desired spacing or multiple of the desired spacing of a desired rib member  64  ( FIG. 17 ) to be formed by the apparatus  200 , such as further described herein. More specifically, in various embodiments, the center to center distance  224  of each pair of machine heads  225  may generally correspond to a spacing or distance  97  of the grid structure  62  ( FIG. 17 ). 
     For example, the spacing or distance  97  of the grid structure  62  may correspond to a spacing or distance between each pair of rib members  64  along a first direction  76  or second direction  78 . Still further, the spacing or distance  97  of the rib members  64  may refer to a spacing or distance between each pair of first rib members  66  or second rib members  68 . As another example, each structure of the composite component  210  to be formed may define a dimension X of length or width (e.g., spacing or distance  97  shown in  FIG. 17 ). The desired center to center spacing (i.e., the distance  224 ) of each adjacent pair of machine heads  225  may be at least approximately equal the dimension X of the structure. As another example, the desired center to center spacing (i.e., the distance  224 ) of each adjacent pair of machine heads  225  may be at least approximately a multiple of the dimension X of the structure. For example, the center to center spacing may be two times (i.e., 2×), or three time (i.e., 3×), or four times (i.e., 4×), etc. of the dimension of the structure. As still another example, the plurality of machine heads  225  may generally move along a first direction (e.g., first direction  211  depicted in  FIGS. 8A-8F  or  FIGS. 9A-9B ) to form the structure, and then move along a second direction (e.g., second direction  212  depicted in  FIGS. 8A-8F  or  FIGS. 9A-9B ) opposite of the first direction to further form the structure. 
     As yet another example, when the plurality of machine heads  220  are generally parallel with the length  23  of the composite component  210 , such as generally depicted in  FIGS. 8A-8F , the center to center spacing or distance  224  along the first axis  201  may generally correspond to or at least approximately equal the desired spacing or distance  97  of the grid structure  62  generally depicted in  FIG. 17  along a direction corresponding to the first axis  201 . As still another example, when the plurality of machine heads  220  are generally parallel with the width  25  of the composite component  210 , such as generally depicted in  FIGS. 9A-9B , the center to center spacing or distance  224  along the first axis  201  may generally correspond to or at least approximately equal the desired spacing or distance  97  of the grid structure  62  generally depicted in  FIG. 17  along another direction corresponding to the first axis  201 . Still further, as previously described, the center to center spacing or distance  224  may be a multiple of the spacing or distance  97  of the grid structure  62 . In one embodiment, the center to center spacing or distance  224  may be more specifically an integer multiple of the spacing or distance  97  of the grid structure  62 . 
     Furthermore, the spacing  97  of the grid structure  62  along a second direction (e.g., second direction  212  along the first axis  201  to which the plurality of machine heads  220  is aligned) is modifiable via the instructions at the controller of the apparatus  200  as the center to center spacing  97  of the grid structure  62  along the opposite direction (e.g., first direction  211 ) is generally independent of the center to center spacing or distance  224  of the machine heads  225  when moving the plurality of machine heads  220  along the same direction in which the plurality of machine heads  220  is aligned. 
     It should further be noted that the spacing or distance  97  of the grid structure  62  along a second direction opposite of the first direction may be modified via instructions at the controller (e.g., computer numeric control) of the apparatus  200  as the formed structure (e.g., second member  68 ,  FIG. 17 ) along the second direction may generally be independent of another structure (e.g., first member  66 ,  FIG. 17 ) along the first direction relative to the spacing  97  between each pair of members. 
     Referring to  FIG. 8E , in another embodiment, the apparatus  200  further defines a second plurality of machine heads  220   a  adjacent to the plurality of machine heads  220  coupled to the second frame  232 . For example, the second plurality of machine heads  220   a  may be disposed on an opposing or another side or face of the second frame  232  such disposing the second plurality of machine heads  220   a  adjacent to the plurality of machine heads  220  along the second axis  202 . As previously described, the second plurality of machine heads  220   a  may be independently moveable along the third axis  203  relative to the plurality of machine heads  220 . Still further, each machine head  225  may be independently moveable along the third axis  203  relative to another machine head  225 . 
     In various embodiments, such as generally provided in  FIG. 8E , two or more of the machine heads  225  may operate in together to print or deposit a material, fluid, or both, to the mold  58 . For example, the machine head  225  of the plurality of machine heads  220  may deposit or extrude a first resin material to form a grid structure  62  of the composite component  210 . The machine head  225  of the second plurality of machine heads  220 A may deposit or extrude a second resin material, same as or different from the first resin material. As another example, the machine head  225  of the second plurality of machine heads  220 A may provide a flow of fluid, such as air, inert gas, or liquid fluid, to clear or clean the surface onto which the grid structure  62  is formed. In another embodiment, the machine head  225  of the second plurality of machine heads  220 A may provide a heat source such as to aid curing of the resin material deposited onto the surface. In still another embodiment, the machine head  225  may define a surface preparation tool, such as an abrasion tool, deburr tool, or cleaning tool. 
     Referring now to  FIGS. 9A and 9B , further embodiments of the apparatus  200  are generally provided. The embodiments generally provided in regard to  FIGS. 9A and 9B  are configured substantially similarly as one or more of the embodiments shown and described in regard to  FIGS. 8A-8F . However, in  FIGS. 9A and 9B , the first axis  201  is substantially parallel to the width or chord  25  of the composite component  210  (e.g., the rotor blade panel  21 ). The second axis  202  is further defined substantially parallel to the length or span  23  of the composite component  210 . The plurality of machine heads  220  are in adjacent arrangement along the first axis  201 , such as to extend generally along the width or chord  25  of the composite component  210 . 
     Referring still to  FIGS. 9A and 9B , the first frame assembly  230  may generally include a plurality of the second frame  232  to which the plurality of machine heads  220  are attached to each. For example, the plurality of second frames  232  may each be independently moveable along the second axis  202  (e.g., along the length or span  23  of the rotor blade panel  21 ), such as generally depicted in  FIG. 9B . Furthermore, the plurality of machine heads  220  coupled to each second frame  232  may each be independently moveable along the first axis  201  (e.g., along the width or chord  25  of the rotor blade panel  21 ). Referring now to  FIG. 9B , one or more of the plurality of machine heads  220  coupled to each second frame  232  may be moveable away from the mold  58  or composite component  210  such as to provide an opening or vertical clearance along the third axis  203 . The clearance or opening may enable placement and removal of the mold  58 , the outer skin  56 , or both, such as described in regard to  FIGS. 8A-8F . 
     In various embodiments, the plurality of machine heads  220  may be arranged along the first axis  201  at least approximately 50% or greater of the width  25  of the composite component  210  to be formed by the apparatus  200 . In still other embodiments, the plurality of machine heads  220  is arranged along the first axis  201  at least approximately 70% or greater of the width  25  of the composite component  210  to be formed by the apparatus  200 . In still yet other embodiments, the plurality of machine heads  220  is arranged along the first axis  201  at least approximately 100% or greater of the width  25  of the composite component  210  to be formed by the apparatus  200 . In other embodiments (e.g.,  FIG. 9A ), the plurality of machine heads  220  may extend at least the entire width or chord  25 , or greater, of the mold  58  or composite component  210  to be formed. 
     In one embodiment, the plurality of machine heads  220 , the mold  58 , or both, is moveable to dispose at least the front head  221  along the first axis  201  beyond the width or chord  25  of the composite component  210  to be formed along the first direction  211 . In another embodiment, the mold  58 , the plurality of machine heads  220 , or both, is moveable to dispose at least the rear head  222  along the first axis  201  beyond the width or chord  25  of the composite component  210  along the second direction  212  opposite of the first direction  211 . For example, the plurality of machine heads  220  is moveable along the first axis  201  such as dispose one or more of the machine heads  225  proximate to (e.g., adjacent or vertically over) the mold  58 , the composite component  210 , or both, along the first axis  201 . The second frame  232  is moveable along the second axis  202  to dispose the plurality of machine heads  220  along the length or span  23  of the composite component  210 . One or more of the second frame  232  may be utilized to be moveable to encompass at least the entire length or span  23  of the composite component  210 . 
     Referring still to the embodiments generally provided in  FIGS. 8A-8F  and  FIGS. 9A-9B , the apparatus  200  may further include a controller configured to control operation of the apparatus  200 . The controller, the plurality of machine heads  220 , and the first frame assembly  230  may together define a computer numeric control (CNC) device. In another embodiment, the controller, the plurality of machine heads  220 , the first frame assembly  230 , and the second frame assembly  240  together define a CNC device. In various embodiments, one or more of the machine heads  225  of each plurality of machine heads  220  may define a material deposition tool defining at least one or more of an extruder, a filament dispensing head, a tape deposition head, a paste dispensing head, a liquid dispensing head, or one or more of a curing tool, a material conditioning tool, or a vacuum tool. At least one or more of the plurality of machine heads  220  is configured to dispense a material from at least one machine head  225  at one or more flow rates, temperatures, and/or pressures independently of one or more other machine heads  225 . Still further, the material conditioning tool may include a surface preparation tool, such as a cleaning or polishing device, a deburr tool, or other abrasion tool, such as a grinding machine head. The vacuum tool may include a vacuum to remove debris, fluid, chips, dust, shavings, excess material in general, or foreign matter in general. 
     It should further be appreciated that the embodiments of the apparatus  200  may include the controller further including one or more processors and one or more memory devices utilized for executing at least one of the steps of the embodiments of the method described herein. The one or more memory devices can store instructions that when executed by the one or more processors cause the one or more processors to perform operations. The instructions or operations generally include one or more of the steps of embodiments of the method described herein. The instructions may be executed in logically and/or virtually separate threads on the processor(s). The memory device(s) may further store data that may be accessed by the processor(s). The apparatus  200  may further include a network interface used to communicate, send, transmit, receive, or process one or more signals to and from the controller and to/from at least one of the first frame assembly  230 , the second frame assembly  240 , the mold  58 , or the plurality of machine heads  220 . 
     The present disclosure is further directed to methods for manufacturing composite components  210  having at least one printed reinforcement grid structure  62  formed via 3-D printing, or composite tape deposition reinforcement grid structure  62 , or combinations thereof. As such, in certain embodiments, the composite structure  210  may define the rotor blade panel  21  such as described in regard to  FIGS. 2-7 . The rotor blade panel  21  may include a pressure side surface, a suction side surface, a trailing edge segment, a leading edge segment, or combinations thereof. 3-D printing, as used herein, is generally understood to encompass processes used to synthesize three-dimensional objects in which successive layers of material are formed under computer control to create the objects. As such, objects of almost any size and/or shape can be produced from digital model data. It should further be understood that the methods of the present disclosure are not limited to 3-D printing, but rather, may also encompass more than three degrees of freedom such that the printing techniques are not limited to printing stacked two-dimensional layers, but are also capable of printing curved shapes. 
     Referring now to  FIG. 8F , the embodiment of the apparatus  200  generally provided is configured substantially similarly to one or more of the embodiments shown or described in regard to  FIGS. 8A-8E . However, in  FIG. 8F , the apparatus  200  further includes a second frame assembly  240  at least partially surrounding the first frame assembly  230 . The second frame assembly  240  includes a first axis frame  241  extended at least partially along the first axis  201  and a second axis frame  232  extended at least partially along the second axis  202 . An extendable third axis member  243  is coupled to the second axis frame  242 . A holding device  245  is coupled to the third axis member  243 . The holding device  245  is configured to couple to the outer skin  56 , the mold  58 , or both, for movement or translation to the grid  205  vertically under the plurality of machine heads  220  along one or more of the first axis  201 , the second axis  202 , or the third axis  203 . 
     In various embodiments, the holding device  245  is configured to affix to and release from an outer skin  56  to place or remove from the mold  58  at the grid  205 . In one embodiment, the holding device  245  defines a vacuum/pressure tool. For example, the holding device  245  may apply a vacuum against the outer skin  56  such as to generate a suction force that affixes the outer skin  56  onto the holding device  245 . The second frame assembly  240  translates the holding device  245  along at least one of the first axis  201  and the second axis  202  and extends along the third axis  203  to place the outer skin  56  onto the mold  58 . The holding device  245  may further discontinue vacuum to release the outer skin  56  onto the mold  58 . In various embodiments, the holding device  245  may further apply a vacuum through the outer skin  56 , such as through one or more openings, to generate a suction force pulling the outer skin  56  to the mold  58 . The holding device  245  may further apply a pressure, such as a force of air or inert gas, or press upon the outer skin  56  such as by extending the third axis member  243  toward the mold  58  along the third axis  203 . For example, applying pressure upon the outer skin  56  and the mold  58  seals at least a perimeter of the outer skin  56  onto the mold  58 . In other embodiments, the mold  58  may include a vacuum tool or vacuum line to generate a suction force pulling the outer skin  56  onto the mold  58 . 
     In one embodiment, the holding device  245  may further apply thermal energy (e.g., heat) to at least a portion of the outer skin  56  such as to enable the outer skin  56  to at least substantially conform to a contour of the mold  58 . For example, heating at least a portion of the fiber-reinforced outer skin  56  may generally include heating at least a portion of the outer skin  56  to at least a first temperature threshold. In various embodiments, the first temperature threshold defines a temperature at least approximately between a glass transition temperature of the resin material and a melting temperature of the resin material of the fiber reinforced outer skin  56 . 
     In various embodiments, applying thermal energy to the outer skin  56  via the holding device  245  may occur before applying pressure or vacuum to the outer skin  56  to affix to the mold  58 . In other embodiments, applying thermal energy to the outer skin  56  may occur at least approximately simultaneously as applying pressure or vacuum to the outer skin  56  to affix to the mold  58 . In still other embodiments, applying thermal energy to the outer skin  56  may occur after applying pressure or vacuum to the outer skin  56  to affix the outer skin  56  to the mold  58 . 
     Another embodiment of the method of manufacturing the composite component  210  includes manufacturing a plurality of the composite components  210 . The method includes the steps generally described above in regard to  FIGS. 8A-8F  and  FIGS. 9A-9B . The method may further include placing a second fiber-reinforced outer skin  56   a  onto a second mold  58   a  via the holding device  245 . The second mold  58   a  is generally disposed adjacent to the first mold  58 , such as adjacent along the first axis  201  or the second axis  202 , such as generally shown and described in regard to  FIGS. 8C, 8D, and 8F . 
     The method generally includes heating at least a portion of the second fiber-reinforced outer skin  56   a  to at least a first temperature threshold, applying pressure onto the second outer skin  56   a  and the second mold  58   a  to seal at least a perimeter of the second outer skin  56   a  onto the second mold  58   a , and forming a plurality of rib members  62  at the second outer skin  56   a , such as described in regard to the first outer skin  56 . 
     It should be appreciated that the method generally includes translating, via the first frame assembly  230  the plurality of machine heads  220  along one or more of the first axis  201 , the second axis  202 , or the third axis  203  proximate to the first outer skin  56 , such as to print, apply, or deposit the resin material to form the grid structure  56  or to prepare the surface of the outer skin  56  (e.g., clean, machine, remove material, apply heat, apply cooling fluid, etc.). Approximately concurrently, or serially, the second frame assembly  240  may translate the holding device  245  along the first axis  201 , the second axis  202 , or the third axis  203  to dispose the second outer skin  56   a  proximate to the mold  58   a  when the plurality of machine heads  220  is proximate to the first outer skin  56  at the first mold  58 . As such, the second frame assembly  240  and holding device  245  may operate on the second outer skin  56   a  and the second mold  58   a  while another composite component  210  of the first outer skin  56  is being developed. 
     The method may further include translating, via the first frame assembly  230 , the plurality of machine heads  220  along one or more of the first axis  201 , the second axis  202 , or the third axis  203  proximate to the second outer skin  56   a  at the second mold  58   a  and translating, via the second frame assembly  240 , the holding device  245  to the first mold  58  when the plurality of machine heads  220  is proximate to the second outer skin  56   a  at the second mold  58   a . As such, the holding device  245  may proceed to remove or otherwise operate on the first outer skin  56  from the first mold  58  via the holding device  245 . Following completion of the composite component  210  at the second mold  58   a , the holding device  245  may further translate to the second mold  58   a  to remove the composite component  210 . Generally prior to or following forming the composite component  210  via the plurality of machine heads  220 , the holding device  245  generally translates along one or more of the first axis  201 , the second axis, or the third axis  203  away from the mold  58  to enable access for the plurality of machine heads  220  to form the composite component  210 . 
     Referring particularly to  FIGS. 8F and 12 , one embodiment of the method includes placing a mold  58  relative to an apparatus  200 . More specifically, as shown in the illustrated embodiments, the method may include placing the mold  58  into the grid  205 . Further, as shown in  FIGS. 8F, 10, and 12 , the method of the present disclosure further includes forming one or more fiber-reinforced outer skins  56  in the mold  58  of the composite component  210  (e.g., rotor blade panel  21 ). In certain embodiments, the method includes placing onto the mold  58  the outer skin(s)  56  that may include one or more continuous, multi-axial (e.g. biaxial) fiber-reinforced thermoplastic or thermoset outer skins. Further, in particular embodiments, the method of forming the fiber-reinforced outer skins  56  may include at least one of injection molding, 3-D printing, 2-D pultrusion, 3-D pultrusion, thermoforming, vacuum forming, pressure forming, bladder forming, automated fiber deposition, automated fiber tape deposition, or vacuum infusion. 
     Composite materials, such as may be utilized in the composite component  210 , may generally include a fibrous reinforcement material embedded in matrix material, such as a polymer material (e.g., polymer matrix composite, or PMC). The reinforcement material serves as a load-bearing constituent of the composite material, while the matrix of a composite material serves to bind the fibers together and act as the medium by which an externally applied stress is transmitted and distributed to the fibers. 
     The method may also include forming the grid structure  62  directly to the fiber-reinforced outer skin(s)  56  via one or more of the plurality of machine heads  220  of the apparatus  200 . Forming the grid structure  62  may include applying or depositing a composite tape onto the outer skin  56 . PMC materials may be fabricated by impregnating a fabric or continuous unidirectional tape with a resin (prepreg), followed by curing. For example, multiple layers of prepreg may be stacked or laid-up together to the proper thickness and orientation for the part, such as the grid structure  62 , and then the resin may be cured or solidified via one or more machine heads  225  to render a fiber reinforced composite component  210 . The bundles of fibers may be impregnated with a slurry composition prior to forming the preform or after formation of the preform. The preform may then undergo thermal processing via one or more of the plurality of machine heads  220  or the holding device  245 , such as to solidify or cure the composite component  210 , or a portion thereof, such as the grid structure  62 . 
     In addition, as shown, the outer skin(s)  56  of the rotor blade panel  21  may be curved. In such embodiments, the method may include forming the curvature of the fiber-reinforced outer skins  56 . Such forming may include providing one or more generally flat fiber-reinforced outer skins, forcing the outer skins  56  into a desired shape corresponding to a desired contour via the holding device  245 , and maintaining the outer skins  56  in the desired shape during printing and depositing. The method may further include heating at least a portion of the fiber-reinforced outer skin  56  to at least a first temperature threshold defining a temperature at least approximately between a glass transition temperature of the resin material and a melting temperature of the resin material. As such, the outer skins  56  generally retain their desired shape when the outer skins  56  and the grid structure  62  printed thereto are released. In addition, the apparatus  200  may be adapted to include a tooling path that follows the contour of the rotor blade panel  21 . 
     The method may also include printing and depositing the grid structure  62  directly to the fiber-reinforced outer skin(s)  56  via the apparatus  200 . More specifically, as shown in  FIGS. 11, 12, 14, and 17 , the apparatus  200  is configured to print and deposit a plurality of rib members  64  that intersect at a plurality of nodes  74  to form the grid structure  62  onto an inner surface of the one or more fiber-reinforced outer skins  56 . As such, the grid structure  62  bonds to the fiber-reinforced outer skin(s)  56  as the structure  62  is being deposited, which eliminates the need for additional adhesive and/or curing time. For example, in one embodiment, the apparatus  200  is configured to print and deposit the rib members  64  onto the inner surface of the one or more fiber-reinforced outer skins  56  after the formed skin(s)  56  reach a desired state that enables bonding of the printed rib members  64  thereto, i.e. based on one or more parameters of temperature, time, and/or hardness. Therefore, in certain embodiments, wherein the skin(s)  56  are formed of a thermoplastic matrix, the apparatus  200  may immediately printed the rib members  64  thereto as the forming temperature of the skin(s)  56  and the desired printing temperature to enable thermoplastic welding/bonding can be the same). More specifically, in particular embodiments, before the skin(s)  56  have cooled from forming, (i.e. while the skins are still hot or warm), the apparatus  200  is configured to print and deposit the rib members  64  onto the inner surface of the one or more fiber-reinforced outer skins  56 . For example, in one embodiment, the apparatus  200  is configured to print and deposit the rib members  64  onto the inner surface of the outer skins  56  before the skins  56  have completely cooled. In addition, in another embodiment, the apparatus  200  is configured to print and deposit the rib members  64  onto the inner surface of the outer skins  56  when the skins  56  have partially cooled. Thus, suitable materials for the grid structure  62  and the outer skins  56  can be chosen such that the grid structure  62  bonds to the outer skins  56  during deposition. Accordingly, the grid structure  62  described herein may be printed using the same materials or different materials. 
     For example, in one embodiment, a thermoset material may be infused into the fiber material on the mold  58  to form the outer skins  56  using vacuum infusion. As such, the vacuum bag is removed after curing and the one or more thermoset grid structures  62  can then be printed onto the inner surface of the outer skins  56 . Alternatively, the vacuum bag may be left in place after curing. In such embodiments, the vacuum bag material can be chosen such that the material would not easily release from the cured thermoset fiber material. Such materials, for example, may include a thermoplastic material such as poly methyl methacrylate (PMMA) or polycarbonate film. Thus, the thermoplastic film that is left in place allows for bonding of thermoplastic grid structures  62  to the thermoset skins with the film in between. 
     In addition, the method of the present disclosure may include treating the outer skins  56  to promote bonding between the outer skins  56  and the grid structure  62 . More specifically, in certain embodiments, the outer skins  56  may be treated using flame treating, plasma treating, chemical treating, chemical etching, mechanical abrading, embossing, elevating a temperature of at least areas to be printed on the outer skins  56 , and/or any other suitable treatment method to promote said bonding via one or more of the machine heads  225  such as shown and described in regard to  FIGS. 8A-8F  and  FIGS. 9A-9B . In additional embodiments, the method may include forming the outer skins  56  with more (or even less) matrix resin material on the inside surface to promote said bonding, such as via the plurality of machine heads  220 , or in conjunction with the second plurality of machine heads  220   a , such as shown and described in regard to  FIG. 8E . In additional embodiments, the method may include varying the outer skin thickness and/or fiber content, as well as the fiber orientation. 
     Further, the method of the present disclosure includes varying the design of the grid structure  62  (e.g. materials, width, height, thickness, shapes, etc., or combinations thereof). As such, the grid structure  62  may define any suitable shape so as to form any suitable structure component, such as the spar cap  48 ,  50 , the shear web  35 , or additional structural components  52  of the rotor blade  16 . For example, as shown in  FIG. 13 , the apparatus  200  may begin printing the grid structure  62  by first printing an outline of the structure  62  and building up the grid structure  62  with the rib members  64  in multiple passes. As such, machine heads  225  of the apparatus  200  can be designed to have any suitable thickness or width so as to disperse, deposit (e.g., deposit a composite fiber tape) or extrude a desired amount of resin material to create rib members  64  with varying heights and/or thicknesses. Further, the grid size can be designed to allow local buckling of the face sheet in between the rib members  64 , which can influence the aerodynamic shape as an extreme (gust) load mitigation device. 
     More specifically, as shown in  FIGS. 11-17 , the rib members  64  may include, at least, a first rib member  66  extending in a first direction  76  and a second rib member  68  extending in a different, second direction  78 . In several embodiments, as shown in  FIG. 17 , the first direction  76  of the first set  70  of rib members  64  may be generally perpendicular to the second direction  78 . More specifically, in certain embodiments, the first direction  76  may be generally parallel to a chord-wise direction of the rotor blade  16  (i.e. a direction parallel to the width or chord  25  ( FIG. 2 )), whereas the second direction  78  of the second set  72  of rib members  64  may be generally parallel with a span-wise direction of the rotor blade  16  (i.e. a direction parallel to the length or span  23  ( FIG. 2 )). In still various embodiments, the first direction  76  may correspond to a direction along the first axis  201  generally shown and described in regard to  FIGS. 8A-8F  and  FIGS. 9A-9B . Alternatively, the second direction  78  may generally correspond to a direction along the second axis  202  generally shown and described in regard to  FIGS. 8A-8F  and  FIGS. 9A-9B . Alternatively, in one embodiment, an off-axis orientation (e.g. from about 20° to about 70° relative to the first axis  201  or the second axis  202 ) may be provided in the grid structure  62  to introduce bend-twist coupling to the rotor blade  16 , which can be beneficial as passive load mitigation device. Alternatively, the grid structure  62  may be parallel the spar caps  48 ,  50 . 
     Moreover, as shown in  FIGS. 15 and 16 , one or more of the first and second rib member(s)  66 ,  68  may be printed to have a varying height along a length  84 ,  85  thereof. In alternative embodiments, as shown in  FIGS. 18 and 19 , one or more of the first and second rib member(s)  66 ,  68  may be printed to have a uniform height  90  along a length  84 ,  85  thereof. In addition, as shown in  FIGS. 11, 14, and 17 , the rib members  64  may include a first set  70  of rib members  64  (that contains the first rib member  66 ) and a second set  72  of rib members  64  (that contains the second rib member  68 ). 
     In such embodiments, as shown in  FIGS. 15 and 16 , the method may include forming (e.g., via tape deposition) or printing (e.g., via extrusion) a maximum height  80  of either or both of the first set  70  of rib members  64  or the second set  72  of rib members  64  at a location substantially at (i.e. +/−10%) a maximum bending moment in the rotor blade panel  21  occurs. For example, in one embodiment, the maximum bending moment may occur at a center location  82  of the grid structure  62  though not always. As used herein, the term “center location” generally refers to a location of the rib member  64  that contains the center plus or minus a predetermined percentage of an overall length  84  of the rib member  64 . For example, as shown in  FIG. 15 , the center location  82  includes the center of the rib member  64  plus or minus about 10%. Alternatively, as shown in  FIG. 16 , the center location  82  includes the center plus or minus about 80%. In further embodiments, the center location  82  may include less than plus or minus 10% from the center or greater than plus or minus 80% of the center. 
     In addition, as shown, the first and second sets  70 ,  72  of rib members  64  may also include at least one tapering end  86 ,  88  that tapers from the maximum height  80 . More specifically, as shown, the tapering end(s)  86 ,  88  may taper towards the inner surface of the fiber-reinforced outer skins  56 . Such tapering may correspond to certain blade locations requiring more or less structural support. For example, in one embodiment, the rib members  64  may be shorter at or near the blade tip and may increase as the grid structure  62  approaches the blade root. In certain embodiments, as shown particularly in  FIG. 16 , a slope of the tapering end(s)  86 ,  88  may be linear. In alternative embodiments, as shown in  FIG. 15 , the slope of the tapering end(s)  86 ,  88  may be non-linear. In such embodiments, the tapering end(s)  86 ,  88  provide an improved stiffness versus weight ratio of the panel  21 . 
     In additional embodiments, one or more heights of intersecting rib members  64  at the nodes  74  may be different. For example, as shown in  FIG. 18 , the heights of the second set  72  of rib members  64  are different than the intersecting first rib member  66 . In other words, the rib members  64  can have different heights for the different directions at their crossing points. For example, in one embodiment, the span-wise direction rib members  64  may have a height twice as tall as the height of the chord-wise direction rib members  64 . In addition, as shown in  FIG. 18 , the second set  72  of rib members  64  may each have a different height from adjacent rib members  64  in the second set  72  of rib members  64 . In such embodiments, as shown, the method may include printing each of the second set  70  of rib members  64  such that structures  64  having greater heights are located towards the center location  82  of the grid structure  62 . In addition, the second set  70  of rib members  64  may be tapered along a length  85  thereof such that the rib members  64  are tapered shorter as the rib members approach the blade tip. 
     In further embodiments, as mentioned, the rib members  64  may be printed with varying thicknesses. For example, as shown in  FIG. 17 , the first set  70  of rib members  64  define a first thickness  94  and the second set  72  of rib members  64  define a second thickness  96 . More specifically, as shown, the first and second thicknesses  94 ,  96  are different. In addition, as shown in  FIGS. 20 and 21 , the thicknesses of a single rib member  64  may vary along its length. 
     Referring particularly to  FIG. 17 , the first set  70  of rib members  64  and/or the second set  72  of rib members  64  may be evenly spaced. In alternative embodiments, as shown in  FIGS. 20 and 21 , the first set  70  of rib members  64  and/or the second set  72  of rib members  64  may be unevenly spaced. For example, as shown, the additive methods described herein enable complex inner structures that can be optimized for loads and/or geometric constraints of the overall shape of the rotor blade panel  21 . As such, the grid structure  62  of the present disclosure may have shapes similar to those occurring in nature, such as organic structures (e.g. bird bones, leaves, trunks, or similar). Accordingly, the grid structure  62  can be printed to have an inner blade structure that optimizes stiffness and strength, while also minimizing weight. 
     In several embodiments, the cycle time of printing the rib members  64  can also be reduced by using a rib pattern that minimizes the amount of directional change. For example, 45-degree angled grids can likely be printed faster than 90-degree grids relative to the chord direction of the proposed printer, for example. As such, the present disclosure minimizes printer acceleration and deceleration where possible while still printing quality rib members  64 . 
     In another embodiment, as shown in  FIGS. 10 and 14 , the method may include printing a plurality of grid structures  62  onto the inner surface of the fiber-reinforced outer skins  56 . More specifically, as shown, the plurality of grid structures  62  may be printed in separate and distinct locations on the inner surface of the outer skins  56 . 
     Certain advantages associated with the grid structure  62  of the present disclosure can be better understood with respect to  FIG. 22 . As shown, the graph  100  illustrates the stability of the rotor blade  16  (represented as the buckling load factor “BLF”) on the y-axis versus the weight ratio on the x-axis. Curve  102  represents the stability versus the weight ratio for a conventional sandwich panel rotor blade. Curve  104  represents the stability versus the weight ratio for a rotor blade having a non-tapered grid structure constructed of short fibers. Curve  106  represents the stability versus the weight ratio for a rotor blade having a non-tapered grid structure without fibers. Curve  108  represents the stability versus the weight ratio for a rotor blade having a grid structure  62  constructed of tapered rib members  64  with 1:3 slope and without fibers. Curve  110  represents the stability versus the weight ratio for a rotor blade having a grid structure  62  constructed of tapered rib members  64  with 1:2 slope and without fibers. Curve  112  represents the stability versus the weight ratio for a rotor blade  16  having a grid structure  62  containing short fibers having a first thickness and being constructed of tapered rib members  64  with 1:3 slope. Curve  114  represents the stability versus the weight ratio for a rotor blade  16  having a grid structure  62  containing short fibers having a second thickness that is less than the first thickness and being constructed of tapered rib members  64  with 1:3 slope. Thus, as shown, rib members  64  containing fibers maximize the modulus thereof, while thinner rib members minimize the weight added to the rotor blade  16 . In addition, as shown, higher taper ratios increase the buckling load factor. 
     Referring now to  FIGS. 23-25 , various additional features of the grid structure  62  of the present disclosure are illustrated. More specifically,  FIG. 23  illustrates a partial, top view of one embodiment of the printed grid structure  62 , particularly illustrating one of the nodes  74  thereof. As shown, the apparatus  200  may form at least one substantially 45-degree angle  95  for a short distance at one or more of the plurality of nodes  74 . As such, the 45-degree angle  95  is configured to increase the amount of abutment or bonding at the corners. In such embodiments, as shown, there may be a slight overlap in this corner node. 
     Referring particularly to  FIG. 24 , a partial, top view of one embodiment of the printed grid structure  62  is illustrated, particularly illustrating a start printing location and an end printing location of the grid structure  62 . This helps with the startup and stop of printing the ribs. When the apparatus  200  begins to print the rib members  64  and the process accelerates, the extruders may not perfectly extrude the resin material. Thus, as shown, the apparatus  200  may start the printing process with a curve or swirl to provide a lead in for the rib member  64 . By extruding this swirl at the start location, the machine heads  225  are given time to more slowly ramp up/down their pressure, instead of being required to instantaneously start on top of a narrow freestanding starting point. As such, the swirl allows for the grid structures  65  of the present disclosure to be printed at higher speeds. 
     In certain instances, however, this start curve may create a small void  99  (i.e. the area within the swirl) in the start region which can create issues as the void  99  propagates up through ongoing layers. Accordingly, the apparatus  200  is also configured to end one of the rib members  64  within the swirl of the start region so as to prevent the void  99  from developing. More specifically, as shown, the apparatus  200  essentially fills the start curve of the one of the rib members  64  with an end location of another rib member  64 . 
     Referring particularly to  FIG. 25 , an elevation view of one embodiment of one of the rib members  64  of the printed grid structure  62  is illustrated, particularly illustrating a base section  55  of the rib members  64  having a wider W and thinner T first layer so as to improve bonding of the grid structure  62  to the outer skins  56  of the rotor blade panel  21 . To form this base section  55 , the apparatus  200  prints a first layer of the grid structure  62  such that the individual base sections  55  define a cross-section that is wider and thinner than the rest of the cross-section of the rib members  64 . In other words, the wider and thinner base section  55  of the rib members  64  provides a larger surface area for bonding to the outer skins  56 , maximum heat transfer to the outer skins  56 , and allows the apparatus  200  to operate at faster speeds on the first layer. In addition, the base section  55  may minimize stress concentrations at the bond joint between the structure  62  and the outer skins  56 . 
     Referring now to  FIGS. 26-31 , the apparatus  200  described herein is also configured to print at least one additional feature  63  directly to the grid structure(s)  62 , wherein heat from the printing bonds the additional features  63  to the structure  62 . As such, the additional feature(s)  63  can be directly 3-D printed into the grid structure  62 . Such printing allows for the additional feature(s)  63  to be printed into the grid structure  62  using undercuts and/or negative draft angles as needed. In addition, in certain instances, hardware for various blade systems can be assembled within the grid structure  62  and then printed over to encapsulate/protect such components. 
     For example, as shown in  FIGS. 26-29 , the additional feature(s)  63  may include auxiliary features  81  and/or assembly features  69 . More specifically, as shown in  FIGS. 26 and 27 , the assembly feature(s)  69  may include one or more alignment structures  73 , at least one handling or lift feature  71 , one or more adhesive gaps or standoffs  95 , or one or more adhesive containment areas  83 . For example, in one embodiment, the apparatus  200  is configured to print a plurality of handling features  71  to the grid structure  62  to provide multiple gripping locations for removing the rotor blade panel  21  from the mold  58 . Further, as shown in  FIG. 24 , one or more adhesive containment areas  83  may be formed into the grid structure  62 , e.g. such that another blade component can be secured thereto or thereby. 
     In particular embodiments, as shown in  FIGS. 27 and 28 , the alignment or lead in structure(s)  73  may include any spar cap and/or shear web alignment features. In such embodiments, as shown, the grid structure(s)  62  may printed such that an angle of the plurality of rib members  64  is offset from a spar cap location so as to create an adhesive containment area  83 . More specifically, as shown, the adhesive containment areas  83  are configured to prevent squeeze out of an adhesive  101 . It should be further understood that such adhesive containment areas  83  are not limited to spar cap locations, but may be provided in any suitable location on the grid structure  62 , including but not limited to locations adjacent to the leading edge  24 , the trailing edge  26 , or any other bond locations. 
     In further embodiments, the alignment structure(s)  73  may correspond to support alignment features (e.g. for support structure  52 ), blade joint alignment features, panel alignment features  75 , or any other suitable alignment feature. More specifically, as shown in  FIG. 27 , the panel alignment features  75  may include a male alignment feature  77  or a female alignment feature  79  that fits with a male alignment feature  77  or a female alignment feature  79  of an adjacent rotor blade panel  21 . 
     Further, as shown in  FIG. 30 , the additional feature(s)  63  may include at least one auxiliary feature  81  of the rotor blade panel  21 . For example, in one embodiment, the auxiliary features  81  may include a balance box  67  of the rotor blade  16 . In such embodiments, the step of printing the additional feature(s)  63  into the grid structure(s)  62  may include enclosing at least a portion of the grid structure  62  to form the balance box  63  therein. In additional embodiments, the auxiliary feature(s)  81  may include housings  87 , pockets, supports, or enclosures e.g. for an active aerodynamic device, a friction damping system, or a load control system, ducting  89 , channels, or passageways e.g. for deicing systems, one or more valves, a support  91 , tubing, or channel around a hole location of the fiber-reinforced outer skins, a sensor system having one or more sensors  103 , one or more heating elements  105  or wires  105 , rods, conductors, or any other printed feature. In one embodiment, for example, the supports for the friction damping system may include sliding interface elements and/or free interlocking structures. For example, in one embodiment, the 3-D printed grid structure  62  offers the opportunity to easily print channels therein for providing warmed air from heat source(s) in the blade root or hub to have a de-icing effect or prevent ice formation. Such channels allow for air contact directly with the outer skins  56  to improve heat transfer performance. 
     In particular embodiments, the sensor system may be incorporated into the grid structure(s)  62  and/or the outer skins  56  during the manufacturing process. For example, in one embodiment, the sensor system may be a surface pressure measurement system arranged with the grid structure  62  and/or directly incorporated into the skins  56 . As such, the printed structure and/the skins  56  are manufactured to include the series of tubing/channels needed to easily install the sensor system. Further, the printed structure and/or the skins  56  may also provide a series of holes therein for receiving connections of the system. Thus, the manufacturing process is simplified by printing various structures into the grid structure  62  and/or the skins  56  to house the sensors, act as the static pressure port, and/or act as the tubing that runs directly to the outer blade skin. Such systems may also enable the use of pressure taps for closed loop control of the wind turbine  10 . 
     In still further embodiments, the mold  58  may include certain marks (such as a positive mark) that are configured to create a small dimple in the skin during manufacturing. Such marks allow for easy machining of the holes in the exact location needed for the associated sensors. In addition, additional sensor systems may be incorporated into the grid structures and/or the outer or inner skin layers  56  to provide aerodynamic or acoustic measurements so as to allow for either closed loop control or prototype measurements. 
     In addition, the heating elements  105  described herein may be flush surface mounted heating elements distributed around the blade leading edge. Such heating elements  105  allow for the determination of the angle of attack on the blade by correlating temperature/convective heat transfer with flow velocity and the stagnation point. Such information is useful for turbine control and can simplify the measurement process. It should be understood that such heating elements  105  may also be incorporated into the outer or inner skin layers  56  in additional ways and are not required to be flush mounted therein. 
     Referring back to  FIG. 26 , the method according to the present disclosure may include placing a filler material  98  between one or more of the rib members  64 . For example, in certain embodiments, the filler material  98  described herein may be constructed of any suitable materials, including but not limited to low-density foam, cork, composites, balsa wood, composites, or similar. Suitable low-density foam materials may include, but are not limited to, polystyrene foams (e.g., expanded polystyrene foams), polyurethane foams (e.g. polyurethane closed-cell foam), polyethylene terephthalate (PET) foams, other foam rubbers/resin-based foams and various other open cell and closed cell foams. 
     Referring back to  FIG. 29 , the method may also include printing one or more features  93  onto the outer skins  56 , e.g. at the trailing and/or leading edges of the rotor blade panels  21 . For example, as shown in  FIG. 29 , the method may include printing at least one lightning protection feature  96  onto at least one of the one or more fiber-reinforced outer skins  56 . In such embodiments, the lightning protection feature  93  may include a cooling fin or a trailing edge feature having less fiber content than the fiber-reinforced outer skins  56 . More specifically, the cooling fins may be directly printed to the inside surface of the outer skins  56  and optionally loaded with fillers to improve thermal conductivity but below a certain threshold to address lightning related concerns. As such, the cooling fins are configured to improve thermal transfer from the heated airflow to the outer skins  56 . In additional embodiments, such features  93  may be configured to overlap, e.g. such as interlocking edges or snap fits. 
     Referring now to  FIGS. 31 and 32 , the additional feature(s)  63  may include an adhesive gap  95  or stand-off, which may be incorporated into the grid structures  62 . Such standoffs  95  provide a specified gap between two components when bonded together so to minimize adhesive squeeze out. As such, the standoffs  95  provide the desired bond gap for optimized bond strength based on the adhesive used. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.