Composite stringer formed by conveyor

Abstract

To provide a method for manufacturing a stringer along a continuously moving production line.SOLUTION: An exemplary device for forming a composite structure includes: an expandable pallet 112 having a forming surface configured to receive a lamination charge 116 thereon; and a die conveyor 118 with a plurality of die sections 120 for progressively pressing the lamination charge into a recess 122 defined by the expandable pallet when the expandable pallet is moved against the die conveyor at parallel travel speeds. The die conveyor drives the plurality of die sections at a certain angle to the expandable pallet, and the plurality of die sections mold the lamination charge into at least a portion of a shape of the composite structure.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates generally to systems and methods for forming composite structures using expandable pallets, and more particularly to the manufacture of composite components along a moving production line through the use of expandable pallets and multiple die sections on a die conveyor.

Background Art

[0002] Modern aircraft designs use various components such as stringers to resist bending, torsional, shear, and direct loads along the fuselage of the aircraft. Stringers are typically formed from lightweight composite materials, including, for example, tapes or fabrics with fibers embedded in a resin matrix. The composite layup is processed using a forming tool to define the shape of the stringer. However, it has been difficult to support the composite layup within the forming tool. For example, one approach requires that the stringer layup be pre-formed in a vertical punch-style forming operation and then moved to an assembly line for further processing. The cycle time associated with the pre-forming method limits the rate at which parts can be produced. Other approaches require a forming tool specific to each part to be manufactured and the need to change machine tools as required. Still other approaches may be able to form only one ply at a time and require multiple passes of the forming apparatus to build a complete laminate.

[0003] To increase efficiency, there is a need for a method for manufacturing stringers along a continuously moving production line.

Summary of the Invention

[0004] In one embodiment, a device for forming a composite structure is described. The device includes an expandable pallet having a forming surface configured to receive a laminated charge thereon, and a die conveyor having a plurality of die sections. The plurality of die sections progressively press the laminated charge into recesses defined by the expandable pallet as the expandable pallet is moved relative to the die conveyor at a parallel speed. The die conveyor drives the plurality of die sections at a certain angle relative to the expandable pallet. The plurality of die sections form the laminated charge into at least a portion of the shape of a composite structure.

[0005] In another embodiment, a system for forming a composite structure is described. The system comprises an expandable pallet having a forming surface configured to receive a laminated charge thereon, a feed assembly on which the expandable pallet with the laminated charge is placed, and a die conveyor having a plurality of die sections. The feed assembly line moves the expandable pallet in linear motion at a parallel velocity. The plurality of die sections progressively press the laminated charge into recesses defined by the expandable pallet as the expandable pallet moves relative to the die conveyor at a parallel velocity. The die conveyor drives the plurality of die sections at an angle to the expandable pallet. The plurality of die sections form the laminated charge into at least a portion of the shape of a composite structure.

[0006] In another embodiment, a method for forming a composite structure is described. The method includes adding a laminated charge onto an expandable pallet, moving the expandable pallet relative to a die conveyor having a plurality of die sections at a parallel speed, and driving the plurality of die sections on the die conveyor at an angle to the expandable pallet to progressively drive the laminated charge deeper into a recess defined by the expandable pallet, thereby shaping the laminated charge into at least a portion of the shape of a composite structure.

[0007] The features, functions, and advantages described above can be realized individually in various examples or combined in yet another example. Further details of the embodiments can be understood by referring to the following description and drawings.

[0008] Novel characteristics that are considered to be features of the illustrated embodiments are specified in the appended claims. However, the exemplary embodiments, as well as preferred modes of use, further purposes, and their descriptions will be best understood by referring to and reading the following detailed description of exemplary embodiments of this disclosure in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0009] [Figure 1] An exemplary embodiment shows an example of a composite structure (e.g., a stringer) having an internal cavity, in which a mandrel including an expandable pallet may be used for manufacturing. [Figure 2] An end view of an embodiment of a device for forming a composite structure, according to an exemplary embodiment, is shown. [Figure 3] A perspective view of a portion of a device for forming a composite structure 100 according to an exemplary embodiment is shown. [Figure 4] A side view of a portion of a device for forming a composite structure 100 according to an exemplary embodiment is shown. [Figure 5] A top view of a portion of a device for forming a composite structure 100 according to an exemplary embodiment is shown. [Figure 6] A rear view of a portion of a device for forming a composite structure 100 according to an exemplary embodiment is shown. [Figure 7] A front view of a portion of a device 110 for forming a composite structure 100, according to an exemplary embodiment, is shown. [Figure 8] A side view of another exemplary configuration of a die conveyor according to an exemplary embodiment is shown. [Figure 9] A side view conceptual diagram of a system for forming a composite structure according to an exemplary embodiment is shown. [Figure 10] A flowchart of one embodiment of a method for forming a composite structure is shown, according to an exemplary embodiment. [Figure 11] A flowchart of the functions used in conjunction with the method shown in Figure 10, according to an exemplary embodiment, is shown. [Figure 12] A flowchart of further functions used in conjunction with the method shown in Figure 10, according to an exemplary embodiment, is shown. [Modes for carrying out the invention]

[0010] This specification will now provide a more comprehensive description of the examples disclosed, with reference to the accompanying drawings. The accompanying drawings show some (but not all) of the examples disclosed. In practice, several different examples may be described, but these examples should not be construed as being limited to those specified herein. Rather, these embodiments are described in such a way as to ensure that the disclosure is comprehensive and complete, and that the scope of this disclosure is fully conveyed to those skilled in the art.

[0011] In several embodiments, a system and method for forming a composite structure includes adding a stacked charge onto an expandable pallet, moving the expandable pallet relative to a die conveyor containing a plurality of die sections at a parallel speed, and driving the plurality of die sections on the conveyor. The plurality of die sections are driven at an angle to the expandable pallet so as to progressively drive the die sections deeper into the recesses defined by the expandable pallet, thereby forming the stacked charge into at least a portion of the shape of the composite structure.

[0012] Referring to the drawings, Figure 1 shows an embodiment of a composite structure 100 (e.g., a stringer) having an internal cavity, in which a mandrel including an expandable pallet may be used for manufacturing, according to an exemplary embodiment. In one arrangement, the composite structure 100 may include a multiply layup of uncured, pre-impregnated reinforcing tape or fabric (i.e., “prepreg”). In the illustrated arrangement, the composite structure 100 comprises a rounded hat section 102 that forms an internal stringer cavity 104, a pair of laterally extending flange sections 106, and a flat outer plate section 108 that integrates with the flange sections 106 during curing. Those skilled in the art will recognize that alternative stringer shapes are possible.

[0013] After curing, all the components shown in Figure 1 form the composite structure 100. In several embodiments described herein, the composite structure 100 is manufactured using devices and systems as described with reference to Figures 2 to 9. A bladder is used to fill the stringer cavity 104 in order to create a hollow trapezoidal space within the composite structure 100.

[0014] The exemplary composite materials used for the composite structure 100 are generally lightweight materials (such as prepregs). This tape or fabric may contain multiple fibers, such as graphite fibers, embedded within a matrix material (e.g., polymers such as epoxy or phenol). The tape or fabric may be unidirectional or woven, depending on the desired degree of reinforcement. Thus, during manufacturing, the prepreg is laid on a tool or mold, and components are used to form the prepreg into the desired shape of the composite structure 100. The composite structure 100 may be of any suitable dimensions to provide various degrees of reinforcement and may contain any number of plies of the prepreg.

[0015] FIG. 2 shows an end view of an example of a device 110 for forming a composite material structure 100 according to an exemplary embodiment. The device 110 includes an expandable pallet 112 having a forming surface 114 configured to receive a laminate charge 116 thereon, and a die conveyor 118 having a plurality of die sections 120 for progressively pressing the laminate charge 116 into a recess 122 defined by the expandable pallet 112 when the expandable pallet 112 is moved relative to the die conveyor 118 at a translation speed. The die conveyor 118 drives the plurality of die sections 120 at an angle relative to the expandable pallet 112. The plurality of die sections 120 shape the laminate charge 116 into at least a portion of the shape of the composite material structure 100.

[0016] In FIG. 2, an end view of the device 110 is shown. As such, only some of the die sections of the plurality of die sections 120 are illustrated.

[0017] The device 110 also includes a frame 124 having support structures 126a - b for holding the die conveyor 118. The frame 124 is shown overhead the expandable pallet 112, but other configurations are possible as well, such as a frame 124 attached (e.g., adjacent) to the side of the expandable pallet 112.

[0018] The die conveyor 118 includes a guide bar on which the plurality of die sections 120 rotate, and wheels. The wheels are mounted on a shaft 128 and are driven by a motor connected to the shaft 128. In turn, the movement of the wheels drives the plurality of die sections 120 around the guide bar.

[0019] Device 110 also includes rails 130a - b having bearing tracks driven by a motor connected to the device 110, and the expandable pallet 112 is disposed on the rails 130a - b. When the bearing track is driven by a motor, similar to a conveyor belt, the expandable pallet 112 is moved in a linear motion under the daikon conveyor 118. Only a single expandable pallet is shown in FIG. 2. However, the device 110 includes a plurality of expandable pallets.

[0020] FIG. 3 shows a perspective view of a portion of the device 110 for forming the composite material structure 100 according to an exemplary embodiment. FIG. 4 shows a side view of a portion of the device 110 for forming the composite material structure 100 according to an exemplary embodiment. FIG. 5 shows a top view of a portion of the device 110 for forming the composite material structure 100 according to an exemplary embodiment. FIG. 6 shows a rear view of a portion of the device 110 for forming the composite material structure 100 according to an exemplary embodiment. FIG. 7 shows a front view of a portion of the device 110 for forming the composite material structure 100 according to an exemplary embodiment.

[0021] FIGS. 3 - 7 show the daikon conveyor 118 and a plurality of expandable pallets 132. The plurality of expandable pallets 132 includes the expandable pallet 112. The rear view shown in FIG. 6 is a view from the side where the expandable pallet 112 enters under the daikon conveyor 118 (of the daikon conveyor). The front view shown in FIG. 7 is a view from the side where the expandable pallet 112 exits from under the daikon conveyor 118 (of the daikon conveyor).

[0022] As shown in Figures 3 and 4, the die conveyor 118 includes a wheel 134 and a guide bar 136. The wheel 134 is driveable to rotate a plurality of die sections 120 around the guide bar 136. For example, the wheel 134 may be a plurality of die sections 120 or a sprocket having teeth that engage with a chain or track to which the plurality of die sections 120 are connected. Furthermore, the wheel 134 and the guide bar 136 are configured so that the die conveyor 118 drives the plurality of die sections 120 at a certain angle relative to a plurality of expandable pallets 132. For example, the first end of the guide bar 136 is offset by a first distance D1 from the forming surface of the plurality of expandable pallets. The second end of the guide bar 136 is offset by a second distance D2 from the forming surface of the plurality of expandable pallets. The first distance D1 is greater than the second distance D2. Thereafter, the die conveyor 118 drives the plurality of die sections 120 at a certain angle relative to the expandable pallets 112. In this configuration, as multiple expandable pallets 132 are moved in linear motion A under the die conveyor 118, multiple die sections 120 gradually push the stacked charge 116 into the recesses of the multiple expandable pallets. For example, as an expandable pallet 112 moves forward under the wheel 134 toward the opposite end of the guide bar 136, the multiple die sections push the stacked charge 116 deeper into the recess 122.

[0023] The angle at which the die conveyor 118 drives the multiple die sections 120 relative to the multiple expandable pallets 132 can vary depending on the desired embodiment. For example, the angle may be 3 degrees, 5 degrees, 10 degrees, etc.

[0024] In some embodiments, the height of the die conveyor 118 is movable vertically (e.g., perpendicular to the linear motion A of the expandable pallet 112). In one embodiment, the vertical movement is passively controlled using (one or more) springs or (one or more) air cylinders coupled to the die conveyor 118. In another embodiment, the vertical movement is actively controlled by (one or more) motors. The vertical movement makes it possible to support and accommodate changes in the thickness of the laminate (e.g., ply drops). Furthermore or alternatively, the height of the rails 130a-b is movable vertically by (one or more) springs, (one or more) air cylinders, or (one or more) motors coupled to the rails 130a-b.

[0025] In some embodiments, the die conveyor 118 drives the multiple die sections 120 at the same speed as the parallel movement speed of the expandable pallet 112. In one embodiment, the parallel movement speed of both the multiple die sections 120 and the expandable pallet may be 6 meters / minute. Driving the multiple die sections 120 at the same speed as the parallel movement speed of the expandable pallet 112 can help reduce shear between the stacked charge 116 and the multiple die sections 120.

[0026] As shown in Figure 7, the expandable pallet 112 includes a pair of pallet members 138a-b. The pair of pallet members 138a-b are two separate blocks that slide towards and away from each other due to their interconnected internal features. In one configuration where the pair of pallet members 138a-b are interconnected, the recess 122 is a small area as shown in Figure 2. Thus, the interconnected pair of pallet members 138a-b define the recess 122 between them. When the pair of pallet members 138a-b slide away from each other, the recess 122 becomes larger. Therefore, the pair of pallet members 138a-b are movable relative to each other and move in parallel to change the size and configuration of the recess 122. Similarly, other pallet members of multiple expandable pallets 132 also include their respective pairs of pallet members.

[0027] As the expandable pallet moves in linear motion A, the multiple dices 120 progressively press the stacked charge 116 (not shown in Figures 3-7) into the recess of the expandable pallet. As the dices press deeper into the expandable pallet, the recess progressively expands in direction B (shown in Figure 6). Direction B is perpendicular to linear motion A. By pressing the stacked charge 116 into the recess 122 of the expandable pallet 112, for example, a pair of pallet members 138a-b are moved outward relative to each other, and the recess 122 is progressively expanded.

[0028] Figure 8 shows a side view of another exemplary configuration of the die conveyor according to an exemplary embodiment. As shown in Figure 8, the die conveyor 140 includes a wheel 142 and a guide bar 144. The die conveyor 140 drives a plurality of die sections 120 at an angle relative to a plurality of expandable pallets 132 between the wheel 142 and a transition point TP. After driving the plurality of die sections 120 at an angle so as to give a residence time after the laminated charge 116 has formed into at least a portion of the shape of the composite structure 100, the die conveyor 140 drives the plurality of die sections 120 at a fixed height relative to the forming surface of the plurality of expandable pallets 132. During the residence time, the plurality of die sections 120 hold the position of the laminated charge 116 in the shape of the composite structure 100.

[0029] In some embodiments, instead of utilizing a die conveyor having both angled and flat sections, the multiple expandable pallets 132 may be moved under a separate die conveyor (not shown). After the multiple expandable pallets have been moved under the die conveyor 118, the separate die conveyor drives the multiple die sections at a fixed height relative to the multiple expandable pallets.

[0030] In some embodiments, after the composite structure 100 is manufactured, the composite structure 100 is elaborately fabricated offline and then supplied to a forming station for further processing. At this stage, the composite structure 100 is pre-formed and further steps of bladder installation, noodle extrusion, compaction, and curing are performed. Thus, in some embodiments for manufacturing, the composite structure 100 remains in a different production area while awaiting to move to the next stage of production.

[0031] In other embodiments, systems for high-speed stringer production along a continuously moving production line are used to continuously produce several composite structures, such as about two or three per minute. Each composite structure may include a stringer package of a desired length prepared for curing.

[0032] Figure 9 shows a side view of a system 150 for forming a composite structure according to an exemplary embodiment. The system 150 includes a die conveyor 118, a plurality of expandable pallets 132 having forming surfaces configured to receive stacked charges 116 on them, and a feed assembly line 152 on which the plurality of expandable pallets 132 are placed. The feed assembly line 152 moves the plurality of expandable pallets 132 in linear motion at a parallel speed (e.g., continuously). In some embodiments, the parallel speed is the same speed at which the die conveyor 118 drives the plurality of die sections 120.

[0033] The feed assembly line 152 includes several different stations for the production of laminated charges 116 and then for post-processing in order to produce composite structures 100. Each of the different stations is located over a portion of a conveyor belt 154 that moves expandable pallets from a plurality of expandable pallets 132 in linear motion relative to each station.

[0034] The first station includes a laminator 156 that simultaneously adds a full set of plies onto a group of expandable pallets. The full set of plies is a lamination charge 116.

[0035] The conveyor belt 154 moves a group of expandable pallets 132 in linear motion (as indicated by the rightward arrow in Figure 9), and then moves the group of expandable pallets, now with stacked charges 116 placed on top, to the next station, which includes a die conveyor 118. As described, the die conveyor 118 progressively presses the stacked charges 116 into the recesses of the expandable pallets.

[0036] The conveyor belt 154 continues to move multiple expandable pallets 132 in linear motion, advancing the expandable pallets, now with stacked charges 116 pressed into recesses, to the next station, which includes a bladder station 158. The bladder station 158 is located behind the die conveyor 118 in the feed assembly line 152, and as the group of expandable pallets passes the bladder station 158, a bladder 159 is added over the stacked charges 116 in the cavity formed by the die conveyor 118.

[0037] The conveyor belt 154 continues to move the multiple expandable pallets 132 in linear motion, advancing the expandable pallets, now equipped with bladders 159, to the next station, which includes an R-section filler station 162 located behind the bladder station 158 in the feed assembly line 152. As the group of expandable pallets passes the R-section filler station 162, the R-section filler 163 is placed in the stacked charge 116.

[0038] Gaps or void regions may be formed by the radial range of any curved fragments of the laminated charge. Such gaps or void regions are typically referred to as “radius filler regions” or “noodle regions.” Radius filler stations fill the radius filler regions or noodle regions with “noodles” made of radius filler components or composite or adhesive / epoxy materials. The “noodles” generally have a triangular cross-section to provide further structural reinforcement to such regions. The radius filler 163 includes carbon fiber reinforced plastic (CFRP) which is placed in the gaps or voids by machine as the expandable pallet 112 moves through the radius filler station 162.

[0039] The conveyor belt 154 continues to move multiple expandable pallets 132 in linear motion, advancing the expandable pallets, now with the installed R-section filler 163, to the next station, which includes a consolidation station 164 located behind the R-section filler station 162 in the feed assembly line 152. As the expandable pallets move through the consolidation station 164, the laminated charge 116 is consolidated into the finished package.

[0040] Therefore, the system 150 operates the feed assembly line 152 by continuously moving multiple expandable pallets 132 in linear motion, enabling the production of composite structures at a speed of approximately several feet per minute. The continuously moving assembly line allows for a substantial improvement in the speed and production efficiency of composite reinforcement, because it does not involve any or any stops for replacement tools that need to be positioned.

[0041] The conveyor belt 154 is shown to have an upper track and a lower track (return track), but this embodiment is not intended to be limiting. In other embodiments, the conveyor belt 154 may be replaced with a carousel conveyor (not shown) that moves multiple expandable pallets 132.

[0042] Figure 10 is a flowchart illustrating one embodiment of a method 200 for forming a composite structure, according to an exemplary embodiment. The method 200 shown in Figure 10 presents one embodiment of a method that may be used together with or with the system 150 and its components. Furthermore, the functions described in relation to Figure 10 may be supplemented, replaced, or combined with the functions and features described above, for example, in relation to Figures 2 to 9. Furthermore, the device or system may be used to perform the logical functions presented in Figure 8, or may be configured to perform such logical functions.

[0043] In one embodiment, Method 200 and any of the features shown in Figures 2 to 9 are considered to be processes for forming a composite structure using die conveyor 118 or any of the die conveyors described herein.

[0044] In some cases, components of a device and / or system may be configured to perform the above functions, and in fact, the components are designed and configured (together with hardware and / or software) to enable such performance. In other embodiments, components of a device and / or system may be arranged to enable or be suitable for the performance of the above functions, for example, when operated in a particular manner. Method 200 includes one or more operations, functions, or actions, as illustrated by one or more of blocks 202-206. Furthermore, the blocks in Figures 11 and 12 may be performed according to one or more of blocks 202-206. Although the blocks are shown in order, these blocks may be performed in parallel and / or in an order different from that described herein. Also, various blocks may be combined into fewer blocks, divided into further blocks, and / or removed based on a desired implementation.

[0045] In some embodiments, one or more blocks of Method 200 may be represented as program code or circuitry used to control a robotic mechanism for forming a composite structure 100. Method 200 and its variations may be performed automatically, for example, using one or more robotic armatures controlled by program code operating according to Method 200, with some tasks being performed manually. Thus, certain functions described in relation to Method 200 may be performed automatically while other parts may be performed manually. Alternatively, all blocks of Method 200 may be performed automatically, or all blocks of Method 200 may be performed manually.

[0046] In block 202, method 200 includes adding the stacked charge 116 onto the expandable pallet 112.

[0047] In block 204, method 200 includes moving an expandable pallet 112 relative to die conveyors 118, 140 containing a plurality of die sections 120 at a parallel speed. In one embodiment, one of the die sections 120 defines a contour that complements the desired shape of the composite structure 100. In some embodiments, the composite structure 100 is a stringer.

[0048] Figure 11 shows a flowchart of a function used in conjunction with the method 200 shown in Figure 10, according to an exemplary embodiment. In particular, Figure 11 shows block 208, which includes an exemplary function for driving multiple die sections 120 on die conveyors 118, 140, which includes driving the multiple die sections 120 at the same speed as the parallel movement speed of the expandable pallet 112 to reduce shear between the stacked charge 116 and the multiple die sections 120.

[0049] Figure 12 shows a flowchart of a further function used in conjunction with the method 200 shown in Figure 10, according to an exemplary embodiment. In particular, Figure 12 shows block 210, which includes exemplary function for driving a plurality of die sections 120 on a die conveyor 140 at a fixed height relative to the expandable pallet 112, after driving the plurality of die sections 120 on the die conveyor 140 at a certain angle relative to the expandable pallet 112 so that the laminated charge 116 has formed into at least a portion of the shape of the composite structure 100.

[0050] Further exemplary and non-exclusive embodiments of this disclosure are described in the following paragraphs.

[0051] In one embodiment of the present disclosure, a device (110) for forming a composite structure (100) comprises an expandable pallet (112) having a forming surface (114) configured to receive a laminate charge (116) thereon, and a die conveyor (118, 140) having a plurality of die sections (120) for progressively pressing the laminate charge into recesses (122) defined by the expandable pallet as the expandable pallet is moved relative to the die conveyor at a parallel speed. In this case, the die conveyor drives the plurality of die sections at an angle to the expandable pallet, and the plurality of die sections form the laminate charge into at least a portion of the shape of the composite structure.

[0052] Optionally, in the device described in the preceding paragraph, the die conveyor drives the multiple die sections at the same speed as the parallel movement speed of the expandable pallet to reduce shear between the stacked charge and the multiple die sections.

[0053] In the device described in any one of the paragraphs mentioned above, optionally, one of the multiple dices defines a contour that complements the desired shape of the composite structure.

[0054] Optionally, in the device described in any one of the preceding paragraphs, the die conveyor (140) drives a plurality of die sections on the die conveyor at an angle to an expandable pallet, and then drives a plurality of die sections on the die conveyor at a fixed height relative to the expandable pallet, such that the laminated charge has formed into at least a portion of the shape of the composite structure and then gives a residence time.

[0055] Optionally, in the device described in any one of the preceding paragraphs, the expandable pallet includes a pair of interconnected pallet members (138a, b) that define a recess between them, and driving a plurality of dices at a certain angle relative to the expandable pallet causes the pair of pallet members to move outward relative to each other, thereby progressively expanding the recess.

[0056] Optionally, in the device described in any one of the preceding paragraphs, the expandable pallet is movable in linear motion under a die conveyor, and as the expandable pallet moves in linear motion under the die conveyor, multiple die sections progressively expand the expandable pallet.

[0057] Optionally, in the device described in any one of the preceding paragraphs, the expandable palette is expandable in a direction perpendicular to the linear motion.

[0058] In another embodiment of the present disclosure, a system (150) for forming a composite structure (100) comprises an expandable pallet (112) having a forming surface (114) configured to receive a laminate charge (116) thereon; a feed assembly line (152) on which the expandable pallet having the laminate charge is placed, the feed assembly line moving the expandable pallet in linear motion at a parallel velocity; and a die conveyor having a plurality of die sections (120) for progressively pressing the laminate charge into recesses defined by the expandable pallet as the expandable pallet is moved relative to the die conveyor (118, 140) at a parallel velocity. In this case, the die conveyor drives the plurality of die sections at an angle to the expandable pallet, and the plurality of die sections form the laminate charge into at least a portion of the shape of the composite structure.

[0059] Optionally, in the device described in the preceding paragraph, the die conveyor drives the multiple die sections at the same speed as the parallel movement speed of the expandable pallet to reduce shear between the stacked charge and the multiple die sections.

[0060] In the device described in any one of the paragraphs mentioned above, optionally, one of the multiple dices defines a contour that complements the desired shape of the composite structure.

[0061] Optionally, in the device described in any one of the paragraphs mentioned above, the composite structure is a stringer.

[0062] Optionally, in the device described in any one of the preceding paragraphs, the die conveyor (140) drives a plurality of die sections on the die conveyor at an angle to an expandable pallet, and then drives a plurality of die sections on the die conveyor at a fixed height relative to the expandable pallet, such that the laminated charge has formed into at least a portion of the shape of the composite structure and then gives a residence time.

[0063] Optionally, in the device described in any one of the preceding paragraphs, the expandable pallet includes a pair of interconnected pallet members (138a, b) that define a recess between them, and driving a plurality of dices at a certain angle relative to the expandable pallet causes the pair of pallet members to move outward relative to each other, thereby progressively expanding the recess.

[0064] Optionally, the device described in any one of the preceding paragraphs further comprises a bladder station (158) located behind the die conveyor in a feed assembly line. In this case, a bladder (159) is added on top of the stacked charge as the expandable pallet passes through the bladder station.

[0065] Optionally, the device described in any one of the preceding paragraphs further comprises an R-filler station (162) in the feed assembly line. In this case, the R-filler (163) is placed in the stacked charge as the expandable pallet passes through the R-filler station.

[0066] In another embodiment of the present disclosure, a method for forming a composite structure (200) includes adding a laminated charge onto an expandable pallet (202), moving the expandable pallet relative to a die conveyor having a plurality of die sections at a parallel speed (204), and driving the plurality of die sections on the die conveyor progressively deeper into recesses defined by the expandable pallet and driving the plurality of die sections at an angle to the expandable pallet so as to form the laminated charge into at least a portion of the shape of a composite structure (206).

[0067] Optionally, the devices described in the preceding paragraph include driving the multiple die sections on the die conveyor at the same speed as the parallel movement speed of the expandable pallet so that the shear between the stacked charge and the multiple die sections is reduced (208).

[0068] In the device described in any one of the paragraphs mentioned above, optionally, one of the multiple dices defines a contour that complements the desired shape of the composite structure.

[0069] Optionally, in the device described in any one of the paragraphs mentioned above, the composite structure is a stringer.

[0070] Optionally, the device described in any one of the preceding paragraphs further includes driving a plurality of die sections on a die conveyor at an angle to an expandable pallet, and then driving a plurality of die sections on a die conveyor at a fixed height relative to an expandable pallet (210), such that the laminated charge has formed into at least a portion of the shape of a composite structure and then gives a residence time.

[0071] The exemplary devices, systems, and methods described herein support the manufacture of composite structures along a continuously moving production line. This significantly improves efficiency, drastically reduces the time required to form composite structures, and drastically reduces the space required for manufacturing. At the same time, the exemplary devices, systems, and methods described herein can also be used to reduce the cost of manufacturing composite structures.

[0072] As used herein, the terms “substantially” or “about” mean that the described characteristics, parameters, or values ​​do not need to be strictly realized, but deviations or variations may occur, including tolerances, measurement errors, measurement accuracy limits, and other factors known to those skilled in the art, not to negate the effects that the characteristics are intended to produce.

[0073] Various embodiments of the (one or more) systems, (one or more) devices, and (one or more) methods disclosed herein include a wide variety of components, features, and functions. It should be understood that various embodiments of the (one or more) systems, (one or more) devices, and (one or more) methods disclosed herein may include, in any combination or subcombination, any component, features, and functions of any of the other embodiments of the (one or more) systems, (one or more) devices, and (one or more) methods disclosed herein, and all such possibilities are intended to be within the scope of this disclosure.

[0074] The descriptions of various advantageous configurations are presented for illustrative and explanatory purposes only and are not intended to be complete or to be limited to the embodiments of the disclosed form. Many modifications and variations will be obvious to those skilled in the art. Furthermore, various advantageous embodiments may represent different advantages compared to other advantageous embodiments. One or more selected embodiments have been chosen and described to illustrate the principle of the embodiment, its practical applications, and to facilitate the understanding of the disclosure of various embodiments and the various modifications suitable for the specific applications considered by those skilled in the art.

Claims

1. A device (110) for forming a composite structure (100), comprising: an expandable pallet (112) having a forming surface (114) configured to receive a laminate charge (116) thereon; a die conveyor having a plurality of die sections (120) for progressively forcing the laminate charge into a recess (122) defined by the expandable pallet as the expandable pallet is moved relative to the die conveyor (118, 140) at a translational speed, the plurality of die sections being driven at an angle relative to the expandable pallet, the plurality of die sections forming the laminate charge into at least a portion of the shape of the composite structure.

2. 2. The device of claim 1, wherein the die conveyor drives the plurality of die sections at the same speed as the translation speed of the expandable pallet to reduce shear between the laminate charge and the plurality of die sections.

3. The device of claim 1 or 2, wherein a die section of the plurality of die sections defines a contour that complements a desired shape of the composite structure.

4. 2. The device of claim 1, wherein the die conveyor (140) drives the die sections on the die conveyor at the angle relative to the expandable pallet and then drives the die sections on the die conveyor at a fixed height relative to the expandable pallet to provide a residence time after the laminate charge has been formed into at least a portion of the shape of the composite structure.

5. the expandable pallet includes a pair of interlocking pallet members (138a, b), the recess being defined between the pallet members (138a, b); 2. The device of claim 1, wherein driving the plurality of die sections at the angle relative to the expandable pallet causes the pair of pallet members to move outward relative to one another, progressively expanding the recesses.

6. the expandable pallet is movable in a linear motion beneath the die conveyor; 10. The device of claim 1, wherein the plurality of die sections progressively expand the expandable pallet as the expandable pallet moves in the linear motion under the die conveyor.

7. The device of claim 6 , wherein the expandable pallet is expandable in a direction substantially perpendicular to the linear motion.

8. A system (150) for forming a composite structure (100), comprising: an expandable pallet (112) having a forming surface (114) configured to receive a laminate charge (116) thereon; a feed assembly line (152) onto which the expandable pallet with the stacked charge is placed, the feed assembly line moving the expandable pallet in a linear motion at a translational velocity; and a die conveyor having a plurality of die sections (120) for progressively forcing the laminate charge into a recess defined by the expandable pallet as the expandable pallet is moved relative to the die conveyor (118, 140) at the translational velocity, the plurality of die sections being driven at an angle relative to the expandable pallet, the plurality of die sections forming the laminate charge into at least a portion of the shape of the composite structure.

9. 9. The system of claim 8, wherein the die conveyor drives the plurality of die sections at the same speed as the translation speed of the expandable pallet to reduce shear between the laminate charge and the plurality of die sections.

10. The system of claim 8 or 9, wherein a die section of the plurality of die sections defines a contour that complements a desired shape of the composite structure.

11. The system of claim 8 , wherein the composite structure is a stringer.

12. 9. The system of claim 8, wherein the die conveyor (140) drives the die sections on the die conveyor at the angle relative to the expandable pallet and then drives the die sections on the die conveyor at a fixed height relative to the expandable pallet to provide a residence time after the laminate charge has been formed into at least a portion of the shape of the composite structure.

13. the expandable pallet includes a pair of interlocking pallet members (138a, b), the recess being defined between the pallet members (138a, b); 9. The system of claim 8, wherein driving the plurality of die sections at the angle relative to the expandable pallet causes the pair of pallet members to move outward relative to each other, progressively expanding the recesses.

14. 10. The system of claim 8, further comprising a bladder station (158) positioned in the feed assembly line after the die conveyor, wherein a bladder (159) is added onto the laminate charge as the expandable pallet passes through the bladder station.

15. 9. The system of claim 8, further comprising a radius filler station (162) in the feed assembly line, wherein radius fillers (163) are placed in the laminate charge as the expandable pallet passes through the radius filler station.

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