Net-shape forming of composite stringers including out-of-plane components

Abstract

To provide an apparatus and method for manufacturing a stringer for reducing wrinkles of the stringer and resin pools.SOLUTION: A forming tool (54) is configured to form a composite loading material (72) into a stringer having a net shape with at least one out-of-place portion. The out-of-plane portion is formed by a shim (74) removably attached to the forming tool (54). A family of the shim may be used for forming a range of out-of-plane portions having various characteristics.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates generally to the manufacturing of composite parts, and more particularly to methods and apparatus for making composite stringers that include out-of-plane portions such as joggles. [Background technology]

[0002] Composite stringers are used in aircraft and other applications for stiffening and load transfer to the skin. In some cases, stringers must be curved along their length or have out-of-plane features, such as joggles. These features make composite stringers more challenging to manufacture because of the stress concentrations that occur when forming them.

[0003] One method for manufacturing composite stringers with out-of-plane features, such as joggles, involves forming a flat composite charge into a die using a punch. After the punch forms the stringer into the desired cross-sectional shape, it is transferred in a kitting tray to a forming die, where the out-of-plane features, such as joggles, are formed into the stringer. Forming joggles in this manner can create stress concentrations and prone to ply wrinkling and resin pooling, which can affect stringer performance. These defective stringers must be reworked and sometimes scrapped.

[0004] It would therefore be desirable to provide a method and apparatus for manufacturing a stringer that reduces stringer wrinkling and resin pooling by forming the stringer to a net shape. Summary of the Invention

[0005] The present disclosure relates generally to the manufacture of composite stringers, and more particularly to a manufacturing process and apparatus for making composite stringers having out-of-plane portions.

[0006] According to one aspect, an apparatus for manufacturing a composite stringer having at least one out-of-plane portion is provided. The apparatus includes a die including a die cavity and a forming tool configured to form a composite charge into the die cavity. The apparatus also includes a shim attached to the forming tool. The shim is configured to form the out-of-plane portion in the composite stringer when the forming tool forms the composite charge into the die cavity.

[0007] According to another aspect, an apparatus for manufacturing a composite stringer is provided. The apparatus includes a punch, a die within which a composite charge is formed by the punch, and a set of shims, each configured to form a different unique portion in the composite charge. Each of the shims is removably attached to the punch, allowing a single punch to manufacture a variety of stringers having different unique portions.

[0008] According to a further feature, there is provided a method for net-shape manufacturing of a composite stringer having an out-of-plane portion, the method including attaching a shim to a molding tool and using the molding tool to mold a composite charge into a composite stringer, the molding including using the shim to form the out-of-plane portion in the composite charge while the composite charge is being molded by the molding tool.

[0009] One advantage of embodiments of the present disclosure is that composite stringers with one or more out-of-plane features, such as joggles, can be formed to a net shape in a single molding operation. Another advantage is that composite stringers can be formed to a net shape with reduced wrinkling and resin pooling. Another advantage is that secondary molding operations previously required to form the out-of-plane features in the stringer can be eliminated. A further advantage is that composite stringers with various out-of-plane features can be manufactured using a set of shims that accommodate a single tooling for various out-of-plane features. Another advantage is that fewer toolings are required to manufacture composite stringers with various unique features, thereby reducing flow time and material and labor costs. A further advantage is that higher quality stringers with out-of-plane features can be manufactured, reducing the need for stringer rework.

[0010] The features, functions, and advantages can be achieved individually in various embodiments of the present disclosure or may be combined in yet other embodiments, further details of which will become apparent by reference to the following description and drawings. [Brief explanation of the drawings]

[0011] The novel features believed distinctive to the illustrative embodiments are set forth in the appended claims, and the illustrative embodiments and preferred modes of use, as well as their objects and features, will best be understood by reference to the following detailed description of illustrative embodiments of the present disclosure, taken in conjunction with the accompanying drawings, in which:

[0012] [Figure 1] FIG. 1 is a perspective view of a composite hat stringer having an out-of-plane portion. [Figure 2] FIG. 2 is an end view showing the cross-sectional shape of the stringer of FIG. 1. [Figure 3] FIG. 1 is a top view of a composite hat stringer attached to a skin. [Figure 4] FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 3. [Figure 5] FIG. 2 is a cross-sectional view of a forming tool set used to punch form the composite stringer of FIG. 1. [Figure 6] 6 is a partial side view of a punch that constitutes part of the former set shown in FIG. 5. FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 5. [Figure 8] FIG. 7 is a view similar to FIG. 6 showing a shim with openings that reduces wrinkling of the stringer as it is bent. [Figure 9] 9 is a view similar to FIG. 8 showing the punch and shim formed into the desired curved profile. [Figure 10] FIG. 10 is a diagram showing the portion indicated as "10" in FIG. 9 together with a portion of the stringer. [Figure 11] This is a diagram showing the part indicated as "11" in Figure 9 together with part of the stringer. [Figure 12] FIG. 10 is a cross-sectional view of a punch and top plate showing an example of magnetic attachment of a shim. [Figure 13] FIG. 13 is a view similar to FIG. 12 showing another example of magnetic attachment of the shim. [Figure 14] FIG. 13 is a view similar to FIG. 12 showing another example of magnetic attachment of the shim. [Figure 15] FIG. 1 is a schematic partial side view of a group of shims. [Figure 16] FIG. 10 is a schematic side view of another group of shims. [Figure 17] FIG. 10 is a schematic side view of yet another group of shims. [Figure 18] 1 is a flowchart of a method for manufacturing a composite stringer having an out-of-plane portion. [Figure 19] FIG. 2 is an exploded perspective view showing a compressor and a shim. [Figure 20] FIG. 20 is a view similar to FIG. 19 showing the shim installed in the compressor. [Figure 21] 20 is a flowchart of a method of manufacturing a composite stringer having an out-of-plane portion using the compressor of FIG. 19 . [Figure 22]FIG. 1 is a cross-sectional view of a compactor with a composite stringer placed in a die ready to be formed / compacted. [Figure 23] 1 is a flowchart of a method for manufacturing a composite stringer including localized out-of-plane portions using a press to convey and form / compress the composite stringer. [Figure 24] 1 is a flowchart of an aircraft production and service method. [Figure 25] FIG. 1 is a block diagram of an aircraft. DETAILED DESCRIPTION OF THE INVENTION

[0013] 1 and 2 , a composite stringer 30 is constructed from a composite laminate of fiber-reinforced plies of a polymer, such as a thermoset or thermoplastic. In the illustrated example, the composite stringer 30 is a hat-shaped stringer including a hat portion 36 and a pair of outwardly extending flanges 44. The hat portion 36 includes a top surface 40 connected to the flanges 44 by a pair of angled sides 42, sometimes referred to as a web. While embodiments of the present disclosure will be described in connection with hat stringers, the principles of the embodiments of the present disclosure can be used to manufacture composite stringers having any of a variety of cross-sectional shapes.

[0014] With particular reference to FIGS. 1 , 3 , and 4 , the composite stringer 30 includes one or more out-of-plane features 34 along its length. In the illustrated example, the out-of-plane features 34 are joggles 35 that include an up / down sloping surface 46 in the cross-section of the composite stringer 30 along its length. However, the joggles 35 are merely one example of various out-of-plane features 34 of the composite stringer 30 that may be required in a particular application. In the illustrated example, the composite stringer 30 is attached to the skin 32 by any suitable means, such as co-curing, adhesive bonding, or fasteners. The skin 32 includes a pad-up 48 of composite plies 50, such as required to locally strengthen a portion of the skin 32. The joggles 35 extend over the pad 48 and have a length and curvature profile that closely matches the cross-sectional shape of the pad 48. Although the composite stringer 30 is shown as having only one joggle 35, it may have any number of joggles 35 with the same or different profiles to accommodate various idiosyncrasies in the skin 32 or other situations, depending on the application.

[0015] 5-7 show a tool set 52 for forming a composite charge 72 into a composite stringer 30 having a joggle 35. The tool set 52 includes a tool 54 and a die 59. The tool, in this example, is a punch 56. The die includes a pair of die members 60 spaced apart to define a die cavity 64. The punch 56 is made of a flexible material, such as elastomer, nylon, or PTFE (polytetrafluoroethylene), and thus can flex as needed. In the illustrated example, the punch 56 is attached to the bottom of a top plate 58, which is flexible and made of, for example, sheet aluminum. However, in other examples, the top plate 58 may be made of an elastomer or other polymer integrally formed with the punch 56. The cross-sectional shape of the punch 56 substantially conforms to the inner mold line (IML) of the hat portion 36 (FIG. 2) of the composite stringer 30.

[0016] The die members 60 are mounted for lateral movement on the lower plate 62. In one example, the die members 60 are comprised of a series of interconnected die blocks, which allow the die members 60 to flex out of the plane. A pair of side plates 70 are fixed to the lower plate 62 outboard of the die members 60. An inflatable side bladder 68 is disposed between each die member 60 and its corresponding side plate 70. The side bladders 68 can be inflated with a fluid, such as air, and function to control the outward lateral movement of the die members 60 during the forming process. The forming tool set 52 can be placed in a press (not shown), which moves the upper and lower plates 58 and 62 relative to one another to move the punch 56 into the die cavity 64 at a desired speed and with a desired force.

[0017] In the illustrated example, the punch 56 is substantially straight along its length. However, in other examples described below, the punch 56 may have one or more curvatures along its length. To form the joggles 35 and other out-of-plane features 34 in the composite stringer 30, a shim 74 having a surface contour that substantially matches the joggles 35 is attached to the punch 56. The shim 74 may be removably attached to the punch 56 and / or top plate 58 by any suitable means, such as double-sided tape, a mechanical latch (not shown), or a magnetic latch, as described below. Thus, various out-of-plane features can be formed by interchangeably attaching shims 74 of different shapes to the same punch 56. Depending on the application, a shim 76 may also need to be attached to the top of the die member 60.

[0018] The shim 74 includes a top surface 80, side surfaces 82, and a flange 84, which form a contour that substantially matches the IML of the joggle 35. The thickness T and other dimensions and features of the shim 74 can depend on the application and the geometry / dimensions of the joggle 35. The shim 74 includes an up / down sloping surface 46 at its outer end, which forms a smooth transition between the shim 74 and the body of the punch 56. The shim 74 can be formed from any suitable material by any of a variety of manufacturing methods. For example, the shim 74 can be formed from laser-sintered nylon or light-cured epoxy manufactured by 3D printing. Although only one shim 74 is shown in the figures, any number of shims 74 can be attached anywhere along the length of the punch 56 to form corresponding out-of-plane portions of the composite stringer 30.

[0019] The stringer forming operation begins with the former set 52 positioned as shown in FIG. 5 and the punch 56 in its raised position. The composite charge 72, which in this embodiment is flat, is placed on the die member 60, straddling the die cavity 64. To form the composite charge 72 into the desired cross-sectional shape of the composite stringer 30, the top plate 58 is lowered, causing the punch 56 to form the composite charge 72 into the die cavity 64. As the punch 56 forms the composite charge 72 into the cross-sectional shape of the composite stringer 30, the shim 74 also forms the joggles 35 and other out-of-plane features in the composite stringer 30. Thus, the out-of-plane features 34 of the stringer 30 are formed at the same time that the stringer 30 is being formed into the desired cross-sectional shape. By simultaneously forming the stringer 30 and the out-of-plane portion 34, distortion of the stringer 30 during molding, which can cause wrinkles and resin accumulation, can be reduced.

[0020] In some examples, the composite stringer 30 is formed along its length into a desired curved profile in a secondary forming process, in which the punch 56 and die 59 are bent by a suitable profile-changing mechanism (not shown). To allow shim 74 to flex as punch 56 is bent, shim 74 includes a set of first slot-like openings 86 that extend completely across the top surface 80 and side surfaces 82 of the shim 74. Optionally, shim 74 may further include a set of second openings 88, which may also be slot-like, for example, extending completely across the top surface 80 of the shim 74 but only partially across the side surfaces 82. The second openings 88 reduce wrinkling and buckling of the composite stringer 30 as it is bent.

[0021] 10 and 11 , when the composite stringer 30 is being bent, the first opening 86 is partially or fully closed (92), allowing the shim 74 to deflect with the punch 56. However, during this bending, the second opening 88 remains open, and the composite charge 72 deforms into the second opening 88, forming wrinkles 90; however, these wrinkles are relatively small in size and therefore do not substantially affect the stringer's performance.

[0022] As previously described, the shim 74 is removably attached to the tooling 54. The shim 74 is removably attached to the tooling 54 using, for example, magnets 96, which allow the shim 74 to be easily attached and detached to accommodate various joggle positions and conditions. The use of magnets 96 allows multiple shims 74 of different shapes to be easily interchanged for use with a single tool. FIG. 12 illustrates a method of shim attachment using one or more magnetic latches 100, each including a magnet 96 embedded in the flange of the shim 74. In this example, the top plate 58 is formed from a magnetic material or a flexible binder material containing a magnetic material. The top plate 58 is attached to the magnets 98 to removably latch the shim 74 to the tooling 54.

[0023] FIG. 13 shows another example of a magnetic latch 100 in which a magnetic material insert 94 is embedded in the top plate 58 and aligned with a magnet 96 embedded in the flange 84 of the shim 74.

[0024] 14 shows yet another example of a magnetic latch 100 in which a magnetic material insert 94 is embedded in the flange 84 of the shim 74. An electromagnet 98 mounted or embedded in the top plate 58 is energized to attract the magnetic material insert 94, thereby removably holding the shim 74 to the tooling 54. Other combinations of magnets and magnetic materials can also be used to magnetically attach the shim 74 to the tooling 54.

[0025] Attention is now directed to Figures 15-17, which illustrate groups 102a, 102b, and 102c of shims 74 that can be used to form any of a variety of out-of-plane features, such as joggles 35, in a composite stringer 30. By providing one or more groups 102a, 102b, and 102c of shims 74 with different characteristics that are commonly used to form out-of-plane features, shims do not need to be custom-manufactured to meet the requirements of a particular application. The shims 74 can be designed to accommodate the various joggles employed in multiple stringers 30. For example, all stringers 30 having joggles 35 within a certain range of slope or height may use the same shims 74. Therefore, it may be desirable to provide a group of shims 74, each with unique characteristics, and then select a specific shim 74 from the group to use to form the joggle 35 in any of the multiple stringers 30.

[0026] Any desired characteristics of the shims 74 can be designed to vary within each group 102a, 102b, 102c. For example, Figure 15 shows group 102a of shims 74 in which the tilt angles RA are RA1 through RA n 16 shows a group 102b of shims 74 in which the lengths of the shims 74 are L1 to L2. n17 shows a group 102c of shims 74 in which the heights of the shims 74 vary linearly or non-linearly from H1 to H n Although not shown, a group 102 of shims 74 may be provided in which multiple shim characteristics are varied, such as, for example, tilt angle, length, and / or height.

[0027] FIG. 18 broadly illustrates the steps of a method for fabricating a composite stringer 30 having one or more out-of-plane portions 34. First, at 104, a shim 74 is attached to a molding tool 54. At 106, the molding tool 54 is used to mold a composite charge 72 into the composite stringer 30, with the shim 74 forming the out-of-plane portions 34 in the composite charge 72 while the charge 72 is being molded by the molding tool 54. Using the shim 74 allows the out-of-plane portions 34 to be formed in the stringer 30 simultaneously as the stringer 30 is being fabricated, rather than forming the out-of-plane portions in a later secondary molding step. Simultaneously forming the out-of-plane portions 34 and the shape of the stringer 30 reduces distortion of the stringer 30, which can lead to ply wrinkling and / or resin pooling, particularly in the areas of the top surface 40 and side surfaces 42.

[0028] 19 and 20, these figures illustrate a forming tool 54 in the form of a compactor 108 that can be used to shape, convey, and / or compress the composite stringer 30, which in this example is a hat stringer. The compactor 108 is constructed with a single-piece hat-shaped body 110 and an integral flange 112 formed from a flexible material, such as an elastomer. The hat-shaped body 110 includes an interior chamber 120 and a series of openings 114, e.g., slots, disposed along the length of the compactor 108. In some examples, the openings 114 are configured to reduce wrinkling of the stringer, e.g., by redirecting stresses induced in the composite charge 72 as the composite stringer 30 is bent. The compactor 108 has end walls 116 with fittings 118 configured to connect the interior chamber 120 to a vacuum source (not shown). When a vacuum is applied to the interior chamber 120, air is drawn through the openings 114, creating a suction effect.

[0029] When the compressor 108 is placed within a correspondingly shaped composite stringer 30 and a vacuum is pulled within the compressor 108, the composite stringer 30 is attracted to the compressor 108, which allows the compressor 108 to lift and transport the composite stringer 30 to a desired location, such as a forming station or kitting tray (neither shown). To form or compress one or more out-of-plane portions 34 in the composite stringer 30, one or more shims 74 may be attached anywhere along the length of the compressor 108, for example, performing a function similar to the shims 74 described above attached to the punch 56. The shims 74 include openings 86, such as slots, that allow air to pass through the shims 74 and into the interior chamber 120 of the compressor 108.

[0030] FIG. 21 broadly illustrates the steps of a method for fabricating and transporting a composite stringer 30 using the compactor 108 of FIG. 19 . First, at 122, one or more shims 74 are loaded into the compactor 108. At 124, the compactor 108 is used as a tool to form the composite charge 72 into the composite stringer 30. At 126, while the composite charge 72 is being formed, the shims 74 attached to the compactor 108 are used to form localized out-of-plane portions in the composite stringer 30. Optionally, at 128, the shims 74 may be removed from the compactor 108 after the composite charge 72 has been formed into the composite stringer 30. At 130, the compactor 108 is used to lift the composite stringer 30 and transport it to a desired location, such as a kitting tray, compaction equipment, or storage location.

[0031] FIG. 22 shows the compactor 108 about to lower (138) the composite stringer 30 into a die cavity 132 in a forming die 134 after using suction from the opening 114 ( FIG. 19 ) to lift the composite stringer 30. The forming die 134 includes a die face 136 that is curved along its length. After the composite stringer 30 is placed in the die cavity 132, a forming pressure is applied to the compactor 108, forming the composite stringer 30 into the curved shape of the die cavity 132. Additionally, during this curve-forming process, the shim 74 forms an out-of-plane portion of the composite stringer 30. Additional pressure applied to the compactor 108 by any suitable means, such as a vacuum bag (not shown), compresses the composite stringer on the forming die 134.

[0032] FIG. 23 generally illustrates the steps of a method for compressing and / or forming a composite stringer 30, including one or more out-of-plane portions 34, into a desired curved shape. First, at 140, a composite charge 72 is punched into a composite stringer 30 having a desired cross-sectional shape. Next, at 142, one or more shims 74 are loaded into a compactor 108. At 144, the compactor 108 is used to lift and transport the composite stringer 30 to a forming die 134 or kitting tray. At 146, the compactor 108 with the shims 74 loaded is used to form and / or compress the composite stringer 30. At 148, the shims 74 are used to form the out-of-plane portions in the composite stringer 30 during forming / compression.

[0033] Embodiments of the present disclosure may be used in a variety of applications, particularly those using composite stiffeners, such as aircraft composite stringers, in aerospace, marine, automotive, and other transportation applications. Accordingly, with reference to FIGS. 24 and 25 , embodiments of the present disclosure may be employed in connection with an aircraft manufacturing and service entry method 150 shown in FIG. 24 and in connection with an aircraft 152 shown in FIG. 25 . The aircraft application of the disclosed embodiments includes various composite stringers having curves, curvatures, thickness variations, and / or one or more out-of-plane portions along their length. Prior to the start of production, the exemplary method 150 includes specification and design 154 of the aircraft 152 and material procurement 156. During production, component and subassembly manufacturing 158 and system integration 160 of the aircraft 152 occur. The aircraft 152 then undergoes certification and delivery 162 and enters service 164. During its service with the customer, the aircraft 152 is subject to a schedule of routine maintenance and service 166, including modifications, reconfigurations, refurbishments, and the like.

[0034] The steps of method 150 may be performed or implemented by a system integrator, a third party, and / or an operator (e.g., a customer). A system integrator may include, for example, any number of aircraft manufacturers and major system subcontractors. A third party may include, for example, any number of vendors, subcontractors, and suppliers. An operator may be, for example, an airline, a leasing company, a military entity, a service organization, etc.

[0035] 25, an aircraft 152 produced by exemplary method 150 may include an airframe 168 having a number of systems 170 and an interior 172. Examples of high-level systems 170 include one or more of a propulsion system 174, an electrical system 176, a hydraulic system 178, and an environmental system 180. The aircraft 152 may also include any number of other systems. Additionally, while described as being used in the aerospace industry, the principles of the present disclosure may also be applied to other industries, such as the marine and automotive industries.

[0036] Systems and methods embodied herein may be employed in any one or more steps in aircraft manufacturing and service method 150. For example, parts and subassemblies produced in manufacturing process 158 may be manufactured similarly to parts and subassemblies produced during the in-service life of aircraft 152. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be employed in manufacturing processes 158 and 160 to substantially increase the speed or reduce the cost of assembly of aircraft 152. Similarly, one or more apparatus embodiments, method embodiments, or a combination thereof may be employed during the in-service life of aircraft 152, for example, but not limited to, maintenance and service 166.

[0037] The present disclosure includes exemplary embodiments according to the following notes.

[0038] Clause 1. An apparatus for manufacturing a composite stringer (30) having at least one out-of-plane portion (34), comprising: a die (59) including a die cavity (64); a molding tool (54) configured to mold a composite charge (72) into the die cavity (64); a shim attached to the molding tool and configured to form an out-of-plane portion in the composite stringer when the molding tool molds the composite charge into the die cavity.

[0039] Clause 2. The apparatus of Clause 1, wherein the forming tool (54) is a punch (56) having a cross-sectional profile that matches the cross-sectional profile of the composite stringer (30).

[0040] Clause 3. The apparatus of Clause 1, wherein the forming tool (54) is a compactor (108) configured to compact the composite stringer (30).

[0041] Appendix 4. The molding tool (54) has a length, 4. The apparatus of any one of claims 1 to 3, wherein the shim (74) extends across the tool (54) and is configured to modify the outer contour of the tool (54) along a portion of the length of the tool (54).

[0042] Appendix 5. The apparatus of any one of appendices 1 to 4, wherein the out-of-plane portion (34) is a joggle (35) in the composite stringer (30).

[0043] Appendix 6. The apparatus of any one of Appendixes 1 to 5, wherein the composite stringer (30) is a hat stringer, and the shim (74) includes a pair of flanges (84) and hat portions (80, 82) that cover the forming tool (54) along a portion of the length of the forming tool (54).

[0044] Supplementary Note 7. The shim (74) is a set of first openings (86) that allow the shim (74) to flex; and a set of second openings (88) into which the composite charge (72) can deform as the composite charge (72) is molded by the molding tool (54).

[0045] Clause 8. The apparatus of any of clauses 1-7, further comprising a magnetic latch (100) configured to removably attach the shim (74) to the molding tool (54).

[0046] Supplementary Note 9. The magnetic latch (100) at least one magnet (96) attached to one of the forming tool (54) and the front shim (74); and an element (94) formed of a magnetic material attached to the other of the forming tool (54) and the shim (74), the element (94) being configured to be magnetically attracted to the magnet (96).

[0047] Appendix 10. An apparatus for manufacturing a composite stringer, comprising: Punch (56) and a die (59) within which the composite charge (72) is formed by the punch (56); a group of shims (102), each configured to form a different unique portion (34) in the composite charge (72); Each of the shims (74) is configured to be removably attached to the punch (56).

[0048] Note 11. Each of the shims (74) has a length (L), a height (H), and a slope (46) having a slope angle (RA); 11. The apparatus of claim 10, wherein the shims (74) differ from each other in at least one of the length (L), the height (H), and the inclination angle (RA).

[0049] Note 12: At least some of the shims (74) a set of first openings (86) that allow the shim (74) to flex; and a set of second openings (88) into which the composite charge (72) may deform as the composite charge (72) is shaped by the punch (56).

[0050] Appendix 13. The apparatus of any one of Appendixes 10 to 12, wherein at least some of the different peculiar portions (34) are joggles (35) in the composite stringer (30).

[0051] Appendix 14. The apparatus of any one of Appendixes 10 to 13, wherein the composite stringer (30) has a hat-shaped cross section (36), and the shim (74) has a cross-sectional shape (80, 82, 84) that matches the hat-shaped cross section (36).

[0052] Appendix 15. A method of manufacturing a net-shape composite stringer (30) having an out-of-plane portion (34), comprising: A shim (74) is attached to the molding tool (54), The method includes using the tooling (54) to form a composite charge (72) into a composite stringer (30), wherein the shim (74) is used to form an out-of-plane portion (34) in the composite charge (72) while the composite charge (72) is being formed by the tooling (54).

[0053] Clause 16. The method of clause 15, wherein attaching the shim (74) includes magnetically attaching the shim (74) to the molding tool (54).

[0054] Clause 17. The method of clause 15 or 16, wherein forming the composite charge (72) into a composite stringer (30) involves punching the composite charge (72) into a die cavity (64).

[0055] Note 18. Furthermore, the shim (74) is formed with a plurality of openings (86) to allow the shim (74) to flex (92); 18. The method of any one of claims 15 to 17, wherein the composite stringer (30) is curved, and in so doing, the shim (74) is deflected.

[0056] Appendix 19. The method of any one of Appendixes 15 to 18, further comprising using the forming tool (54) to lift and transport the composite stringer (30).

[0057] Clause 20. The method of clause 19, further comprising compressing the composite stringer (30) using the tooling (54) after the conveying.

[0058] As used herein, the phrase "at least one" when used with reference to a list of items means that various combinations of one or more of the listed items may be used, and that only one of each item in the list may be required. For example, "at least one of item A, item B, and item C" may include, but is not limited to, item A, item A and item B, or item B. This example may also refer to item A, item B, and item C, or item B and item C. An item may also be a specific object, thing, or category. In other words, "at least one of" means that any number of items from the list may be used in any combination, and not necessarily all of the listed items.

[0059] The description of various exemplary embodiments has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the embodiments to the form disclosed. Many modifications or variations will be apparent to those skilled in the art. Also, different exemplary embodiments may provide different advantages than other exemplary embodiments. The embodiment or embodiments described above have been chosen and described to best explain the principles and practical applications of the embodiments and to enable those skilled in the art to understand the disclosure for various embodiments with various modifications suited to the particular applications envisioned.

Claims

1. 1. An apparatus for manufacturing a composite stringer (30) having at least one out-of-plane portion (34), comprising: a die (59) including a die cavity (64); a molding tool (54) configured to mold a composite charge (72) into the die cavity (64); a shim (74) attached to the molding tool (54) and configured to form an out-of-plane portion (34) in the composite stringer (30) when the molding tool (54) molds the composite charge (72) into the die cavity (64); The shim (74) a set of first openings (86) that allow the shim (74) to flex; a set of second openings (88) into which the composite charge (72) may deform as it is molded by the molding tool (54).

2. The apparatus of claim 1, wherein the forming tool (54) is a punch (56) having a cross-sectional profile that matches the cross-sectional profile of the composite stringer (30).

3. The apparatus of claim 1, wherein the forming tool (54) is a compactor (108) configured to compact the composite stringer (30).

4. The tool (54) has a length, 4. The apparatus of claim 1, wherein the shim extends across the tool and is configured to modify an outer contour of the tool along a portion of the length of the tool.

5. The apparatus of any one of claims 1 to 4, wherein the out-of-plane portion (34) is a joggle (35) in the composite stringer (30).

6. 6. The apparatus of claim 1, wherein the composite stringer is a hat stringer, and the shim includes a pair of flanges and a hat portion that cover the tool along a portion of the length of the tool.

7. The apparatus of any preceding claim, further comprising a magnetic latch (100) configured to removably attach the shim (74) to the forming tool (54).

8. The magnetic latch (100) at least one magnet (96) attached to one of the tool (54) and the front shim (74); an element (94) formed of a magnetic material attached to the other of the forming tool (54) and the shim (74) and configured to be magnetically attracted to the magnet (96).

9. 1. An apparatus for manufacturing a composite stringer, comprising: Punch (56) and a die (59) within which the composite charge (72) is formed by the punch (56); a group of shims (102), each configured to form a different unique portion (34) in the composite charge (72); Each of the shims (74) is configured to be removably attached to the punch (56); At least some of the shims (74) a set of first openings (86) that allow the shim (74) to flex; a set of second openings (88) into which the composite charge (72) may deform as it is shaped by the punch (56).

10. Each of the shims (74) has a length (L), a height (H), and a slope (46) having a slope angle (RA); 10. The apparatus of claim 9, wherein the shims (74) differ from one another in at least one of the length (L), the height (H), and the tilt angle (RA).

11. 11. The apparatus of claim 9 or 10, wherein at least some of the different anomalous portions (34) are joggles (35) in the composite stringer (30).

12. 12. The apparatus of claim 9, wherein the composite stringer has a hat-shaped cross-section and the shim has a cross-sectional shape that matches the hat-shaped cross-section.

13. A method for manufacturing a net-shape composite stringer (30) having an out-of-plane portion (34), comprising: Attaching a shim (74) to the molding tool (54); A method of forming a composite charge (72) into a composite stringer (30) using the forming tool (54), wherein the shim (74) is used to form an out-of-plane portion (34) in the composite charge (72) while the composite charge (72) is being formed by the forming tool (54), comprising: forming a plurality of openings (86) in the shim (74) to allow the shim (74) to flex (92); bending the composite stringer (30) and thereby deflecting the shim (74).

14. The method of claim 13, wherein applying the shim (74) includes magnetically attaching the shim (74) to the tool (54).

15. 15. The method of claim 13 or 14, wherein forming the composite charge (72) into a composite stringer (30) comprises punching the composite charge (72) into a die cavity (64).

16. A method for manufacturing a net-shape composite stringer (30) having an out-of-plane portion (34), comprising: Attaching a shim (74) to the molding tool (54); A method of forming a composite charge (72) into a composite stringer (30) using the forming tool (54), wherein the shim (74) is used to form an out-of-plane portion (34) in the composite charge (72) while the composite charge (72) is being formed by the forming tool (54), comprising: The method further comprises using the forming tool (54) to lift and transport the composite stringer (30).

17. The method of claim 16, further comprising compressing the composite stringer (30) with the tooling (54) after the conveying.

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