Composite forming

Abstract

The invention relates to composite forming. A method of creating a shaped shape in a composite stack with reduced wrinkles is provided. A composite stack is sealed in a vacuum package, the composite stack comprising at least one of a resin or a thermoplastic material. The composite stack is shaped on a tool while the composite stack remains under vacuum in the vacuum package to create a shaped shape in the composite stack.

Description

Technical Field

[0001] The present disclosure relates generally to composite forming and, more particularly, to a composite forming method with reduced wrinkling. Background Art

[0002] Dry carbon fiber fabric can be used for resin infusion applications. Dry carbon fiber fabric is typically formed into the part shape before infusion and curing. Due to the bulk or thickness of dry composite fiber fabric, tooling types may be limited. Inconsistencies such as wrinkles may occur during some forming methods.

[0003] Other materials including non-crete fabrics (NCF) and unidirectional prepreg laminates are also used in forming applications. It is desirable to reduce areas of inconsistency during the forming process.

[0004] Therefore, it is desirable to have methods and apparatus that take into account at least some of the above-mentioned problems and other possible problems. For example, it is desirable to provide additional methods for dry composite fabric forming. In addition, it is desirable to reduce or prevent wrinkling when composite materials are formed. Summary of the Invention

[0005] Embodiments of the present disclosure provide a method for forming a composite structure. A composite layup comprising at least one of a resin or a thermoplastic material is sealed in a vacuum package. The composite layup is formed on a tool while the composite layup is maintained under vacuum in the vacuum package to produce a formed shape in the composite layup.

[0006] Another embodiment of the present disclosure provides a method for forming a composite laminate with reduced wrinkling. The method includes compacting the composite laminate in a vacuum package. While the composite laminate is under vacuum in the vacuum package, forming the composite laminate on a tool to create a formed shape in the composite laminate. The method also includes manipulating the composite laminate while in the formed shape.

[0007] Another embodiment of the present disclosure provides a method for forming a composite laminate. The composite laminate is loaded into a forming machine and a sweeper of the forming machine is used to sweep the composite laminate against a tool.

[0008] Yet another embodiment of the present disclosure provides a method for forming a composite laminate. Layers of material are laid down to form a composite laminate, the composite laminate comprising at least one of a resin or a thermoplastic material. Prior to forming, the composite laminate is compacted by applying a vacuum within a vacuum enclosure. While the composite laminate is under vacuum within the vacuum enclosure, the composite laminate is formed on a tool to produce a formed shape within the composite laminate. While under vacuum, the composite laminate is heated to maintain the formed shape within the composite laminate by adhering the composite laminate.

[0009] The features and functions can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments in which further details can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The novel features which are believed to be characteristic of the illustrative embodiments are set forth in the appended claims. However, the illustrative embodiments, together with the preferred mode of use, further objects and features thereof, will be best understood by reference to the following detailed description of illustrative embodiments of the present disclosure when read in conjunction with the accompanying drawings, in which:

[0011] Figure 1 is a diagram of an aircraft according to an illustrative embodiment;

[0012] Figure 2 is an illustration of a block diagram of a manufacturing environment according to an illustrative embodiment;

[0013] Figure 3 is a flow chart of steps for forming a composite layup according to an illustrative embodiment;

[0014] Figure 4 is a front view of a composite layup sealed in a vacuum envelope within a forming machine according to an illustrative embodiment;

[0015] Figure 5 is a flow chart of a method of forming a composite structure according to an illustrative embodiment;

[0016] Figure 6 is a flow chart of a method of forming a composite structure according to an illustrative embodiment;

[0017] Figure 7 is a flow chart of a method of forming a composite structure according to an illustrative embodiment;

[0018] Figure 8 is a flow chart of a method of forming a composite structure according to an illustrative embodiment;

[0019] Figure 9is an illustration, in block diagram form, of an aircraft manufacturing and service methodology in accordance with an illustrative embodiment; and

[0020] Figure 10 is an illustration, in block diagram form, of an aircraft in which illustrative embodiments may be implemented. DETAILED DESCRIPTION

[0021] Now turn Figure 1 , an illustration of an aircraft is depicted in accordance with an illustrative embodiment. Aircraft 100 has wings 102 and wing 104 attached to fuselage 106. Aircraft 100 includes engines 108 attached to wing 102 and engines 110 attached to wing 104.

[0022] Fuselage 106 has a tail section 112 . Horizontal stabilizer 114 , horizontal stabilizer 116 , and vertical stabilizer 118 are attached to tail section 112 of fuselage 106 .

[0023] Aircraft 100 is an example of an aircraft that may have composite components formed using the illustrative examples. A portion of at least one of wing 102, wing 104, fuselage 106, horizontal stabilizer 114, horizontal stabilizer 116, or vertical stabilizer 118 may be manufactured using the illustrative examples. In some illustrative examples, a reinforcement for at least one of wing 102, wing 104, fuselage 106, horizontal stabilizer 114, horizontal stabilizer 116, or vertical stabilizer 118 may be manufactured using the illustrative examples.

[0024] Now turn Figure 2 , an illustration of a block diagram of a manufacturing environment is depicted in accordance with an illustrative embodiment. Figure 1 A portion of aircraft 100 may be manufactured in manufacturing environment 200 . Composite layup 202 may be formed against tool 204 in manufacturing environment 200 .

[0025] Composite layup 202 is densified before being formed on tool 204. Densifying 244 composite layup 202 before forming 246 is performed by applying vacuum 206 within vacuum enclosure 208 before forming 246. Vacuum enclosure 208 is formed from an impermeable material, such as a vacuum bag. To densify composite layup 202, vacuum 206 is applied to composite layup 202. To apply vacuum 206 to composite layup 202, composite layup 202 is sealed within vacuum enclosure 208. In some illustrative examples, applying vacuum 206 to composite layup 202 within vacuum enclosure 208 reduces thickness 210 of composite layup 202.

[0026] Composite layup 202 may take any desired form. Composite layup 202 includes layers 252 of material 254. Material 254 may take the form of composite prepreg 212 or dry fabric 214. Layers of material 252 are laid up to form composite layup 202. In some illustrative examples, composite layup 202 is substantially flat.

[0027] Composite layup 202 includes at least one of resin 221 or thermoplastic material 216. Thermoplastic material 216 may be present with dry fabric 214 or composite prepreg 212. In some illustrative examples, thermoplastic material 216 takes the form of at least one of thermoplastic veil 218 or thermoplastic suture 220. In these illustrative examples, resin 221 is part of composite prepreg 212. In some illustrative examples, composite layup 202 includes one of a dry fabric 214 preform or a laminate formed from composite prepreg 212. Dry fabric 214 preform is unimpregnated. In some illustrative examples, composite layup 202 includes composite prepreg 212. In some illustrative examples, composite layup 202 includes dry fabric 214. In some illustrative examples, composite layup 202 includes thermoplastic material 216. In some illustrative examples, thermoplastic material 216 includes one of thermoplastic veil 218 and thermoplastic suture 220. In some illustrative examples, one of thermoplastic veil 218 and thermoplastic suture 220 is used with dry fabric 214 to form composite layup 202.

[0028] The composite layup 202 is formed on the tool 204 (or the composite layup 2020 is formed on / onto the tool 204) while the composite layup 202 is maintained under the vacuum 206 in the vacuum enclosure 208. Shaping 246 the composite layup 202 on the tool 204 creates a formed shape 222 in the composite layup 202. By shaping the composite layup 202 on the tool 204 while the composite layup 202 is maintained under the vacuum 206, wrinkles are reduced.

[0029] Tool 204 can have any desired cross-sectional shape. In some illustrative examples, tool 204 has a flat surface. In some illustrative examples, tool 204 can have a bend, twist, curve, or other type of directional change. In some illustrative examples, vacuum package 208 can stretch to accommodate the bend, twist, curve, or other type of feature in tool 204.

[0030] In some illustrative examples, composite layup 202 is swept over (or onto) tool 204 using former 226 to form composite layup 202 on tool 204. In some illustrative examples, sweeper 228 of former 226 sweeps composite layup 202 over tool 204. In some illustrative examples, composite layup 202 sealed in vacuum package 208 is loaded into former 226, and composite layup 202 is formed on tool 204 by former 226 sweeping composite layup 202 over tool 204.

[0031] In some illustrative examples, squeegee 228 may take the form of an inflatable bladder 229 or a compliant scraper 231. In some illustrative examples, compliant scraper 231 may take the form of a finger, a scraper, or any other desired form of squeegee. Squeegee 228 is configured to press composite layup 202, which is sealed in vacuum package 208, against tool 204. Pressing composite layup 202 against tool 204 changes the shape of composite layup 202 to produce formed shape 222 in composite layup 202.

[0032] Inflatable bladder 229 can be filled with any desired type of material. Inflatable bladder 229 can be filled with at least one of air, a different gas, a fluid, a gel, a polymer, or any other desired material. In some illustrative examples, silicone is within inflatable bladder 229.

[0033] In some illustrative examples, the pressure applied by sweep press 228 applies elevated pressure to composite layup 202 during forming 246. The elevated pressure during forming 246 controls wrinkles and bulk.

[0034] In some illustrative examples, during forming 246 of composite layup 202 on tool 204, a level of vacuum 206 in vacuum encapsulation 208 is controlled to control forming 246 of composite layup 202. By controlling the level of vacuum 206 in vacuum encapsulation 208, stiffness 224 of composite layup 202 in vacuum encapsulation 208 may be controlled. By increasing vacuum 206, stiffness 224 of composite layup 202 in vacuum encapsulation 208 may be increased. By decreasing vacuum 206, stiffness 224 of composite layup 202 in vacuum encapsulation 208 may be decreased. In some illustrative examples, decreasing vacuum 206 to decrease stiffness 224 may make it easier to form composite layup 202 against tool 204. In some illustrative examples, decreasing stiffness 224 may allow layers of composite layup 202 to slide more relative to each other.

[0035] After forming 246, processing 248 is performed on composite layup 202. In some illustrative examples, processing 248 is performed on composite layup 202 in vacuum encapsulation 208. Processing 248 includes additional steps for manufacturing. Processing 248 may include at least one of heating 250 or resin infusion 236.

[0036] In some illustrative examples, composite layup 202 is heated while under vacuum 206 to maintain formed shape 222 in composite layup 202. In some illustrative examples, heating 250 composite layup 202 at least one of: melting thermoplastic material 216; and softening thermoplastic material 216. In some illustrative examples, thermoplastic material 216 is at least softened to adhere composite layup 202.

[0037] In some illustrative examples, composite layup 202 is formed from dry fabric 214, and heating 250 is performed before composite layup 202 is removed from vacuum encapsulation 208. In some illustrative examples, composite layup 202 is formed from composite prepreg 212, and composite layup 202 is removed from vacuum encapsulation 208 without heating 250.

[0038] In some illustrative examples, heating 250 composite layup 202 includes melting at least one of thermoplastic veils 218 or thermoplastic sutures 220 in composite layup 202. In some illustrative examples, melting at least one of thermoplastic veils 218 or thermoplastic sutures 220 holds composite layup 202 together. In some illustrative examples, thermoplastic veils 218 reinforce composite layup 202. In some illustrative examples, thermoplastic sutures 220 provide adhesion and hold composite layup 202 together.

[0039] In some illustrative examples, heating 250 composite layup 202 includes heating 250 composite layup 202 on tool 204 in oven 232. In some illustrative examples, heating 250 composite layup 202 includes applying directional heat to composite layup 202 while sweeper 228 of former 226 compresses composite layup 202 against tool 204. In some illustrative examples, heating 250 composite layup 202 includes applying directional heat using heater 230. In some illustrative examples, heater 230 may include at least one of an air blower, an electrically conductive heater in tool 204, or any other type of directional heater. In some illustrative examples, heater 230 includes a heating element integral to one of former 226 or tool 204. In some illustrative examples, composite layup 202 is heated by air blower or other type of heater 230 that is movable relative to former 226.

[0040] In some illustrative examples, prior to heating 250 composite layup 202, composite layup 202 in vacuum encapsulation 208 having formed shape 222 is positioned in at least one of the following ways: on second tool 238; or in second tool 238. In some illustrative examples, prior to heating 250 composite layup 202, composite layup 202 in vacuum encapsulation 208 is positioned in matching metal mold 240. In some illustrative examples, prior to heating 250 composite layup 202, composite layup 202 in vacuum encapsulation 208 is positioned on mandrel 242. In other illustrative examples, heating 250 composite layup 202 is performed prior to removing composite layup 202 from vacuum encapsulation 208.

[0041] In some illustrative examples, after composite layup 202 having formed shape 222 is removed from vacuum encapsulation 208, composite layup 202 having formed shape 222 is placed in at least one of the following ways: in second tool 238; or on second tool 238. In some illustrative examples, second tool 238 may take the form of one of a matched metal die 240 and a mandrel 242.

[0042] In some illustrative examples, vacuum enclosure 208 is sealed against tool 204. In some illustrative examples, resin injection 236 is performed while vacuum enclosure 208 is sealed against tool 204. In some illustrative examples, resin 234 is injected into composite layup 202 while vacuum enclosure 208 is sealed against tool 204. In some illustrative examples, resin injection 236 is performed on composite layup 202 within vacuum enclosure 208. In other illustrative examples, resin injection 236 may be performed on composite layup 202 having formed shape 222 outside of vacuum enclosure 208. In some illustrative examples, resin injection 236 may be performed on composite layup 202 within a matching metal mold 240.

[0043] Figure 2 The illustration of manufacturing environment 200 in FIG. 1 is not meant to imply physical or architectural limitations to the manner in which the illustrative embodiments may be implemented. Components other than or in place of the ones shown may be used. Some components may not be necessary. Furthermore, blocks are presented to illustrate some functional components. When implemented in the illustrative embodiments, one or more of these blocks may be combined, divided, or combined and divided into different blocks.

[0044] Now turn Figure 3 , depicts a flow chart of steps for forming a composite laminate according to an illustrative embodiment. Flowchart 300 may be viewed at Figure 2 300 can be implemented to form Figure 1A composite component of an aircraft 100 .

[0045] In step 302, layup of a composite layup is performed. The composite layup includes one of a prepreg 310 and an interpreg 312. In step 304, a vacuum is applied to the composite layup to consolidate the composite layup.

[0046] While applying vacuum to the composite layup, the composite layup is shaped in step 306. The composite layup is shaped by shaping the composite layup onto the tool. Shaping the composite layup onto the tool creates a shaped shape in the composite layup. Shaping the composite layup while it is under vacuum applies elevated pressure, which can be used to control wrinkles and the volume or thickness of the composite layup.

[0047] After forming in step 306, the composite layup undergoes processing in step 308. In some illustrative examples, at least one processing step may be completed while the composite layup is within the vacuum package. In some illustrative examples, at least one process of step 308 is performed while the composite layup is outside the vacuum package. In some illustrative examples, the processing in step 308 includes at least one of heating 314 or resin infusion 316. In other illustrative examples, step 308 includes placing the composite layup in at least one of the following ways: in a second tool; or on a second tool.

[0048] Now turn Figure 4 , depicts a front view of a composite layup sealed in a vacuum package within a forming machine according to an illustrative embodiment. In view 400 of the forming machine 402, a composite layup 408 sealed in a vacuum package has been loaded into the forming machine 402. The forming machine 402 is Figure 2 406. The forming machine 402 forms a composite layup 408, which is sealed in a vacuum package, onto (or onto) a tool 406 using a sweeper 404. In this illustrative example, the sweeper 404 takes the form of an inflatable bladder. In other illustrative examples, the sweeper 404 may take the form of a compliant scraper, such as a finger, a scraper, or any other desired form of sweeper. The sweeper 404 is configured to press the composite layup 408, which is sealed in a vacuum package, against the tool 406. Pressing the composite layup 408 against the tool 406 changes the shape of the composite layup 408 to produce a formed shape in the composite layup 408.

[0049] Now turn Figure 5 , depicts a flow chart of a method for forming a composite structure according to an illustrative embodiment. The method 500 may be performed to produce a composite part of the aircraft 100. The method 500 may be performed to Figure 2 The method 500 may include: Figure 3 The method 500 may be performed using the steps of the flowchart 300. Figure 4 The forming machine 402 is used to perform.

[0050] Method 500 seals a composite layup in a vacuum package, the composite layup comprising at least one of a resin or a thermoplastic material (operation 502). Method 500 shapes the composite layup on a tool while the composite layup remains under vacuum in the vacuum package to create a formed shape in the composite layup (operation 504). Thereafter, method 500 terminates.

[0051] In some illustrative examples, method 500 densifies the composite layup prior to forming by applying a vacuum within the vacuum enclosure prior to forming (operation 506 ). In some illustrative examples, a thickness of the composite layup is reduced by applying the vacuum within the vacuum enclosure.

[0052] In some illustrative examples, method 500 loads the composite layup sealed in the vacuum package into a forming machine, where forming the composite layup on the tool is performed by the forming machine sweeping the composite layup on the tool (operation 508). The forming machine can include any desired type of sweeper. In some illustrative examples, the sweeper of the forming machine includes at least one of an inflatable bladder or a compliant scraper. The compliant scraper can take the form of a finger, a scraper, or any other desired type of sweeper.

[0053] In some illustrative examples, method 500 varies a vacuum level within a vacuum enclosure during forming of the composite layup on a tool to control the forming of the composite layup (operation 510). In some illustrative examples, varying the vacuum level within the vacuum enclosure varies the stiffness of the composite layup within the vacuum enclosure. In some illustrative examples, when a greater vacuum is applied to the composite layup, the composite layup has a greater stiffness. In some illustrative examples, the vacuum is reduced to reduce the stiffness of the composite layup at portions of the forming process.

[0054] In some illustrative examples, method 500 heats the composite layup while under vacuum to maintain the formed shape in the composite layup (operation 512). In some illustrative examples, heating the composite layup occurs in an oven. In some illustrative examples, heating the composite layup is performed by a directed heat source.

[0055] In some illustrative examples, heating the composite laminate includes melting at least one of a thermoplastic veil or a thermoplastic suture in the composite laminate (operation 514). In some illustrative examples, melting at least one of the thermoplastic veil or the thermoplastic suture holds the composite laminate together. In some illustrative examples, the thermoplastic veil reinforces the material. In some illustrative examples, the thermoplastic suture provides adhesion and holds the composite laminate together.

[0056] In some illustrative examples, heating the composite layup includes heating the composite layup on the tool in an oven (operation 516). In these illustrative examples, the tool and the composite layup can be moved into the oven. In some of these illustrative examples, the vacuum package is sealed against the tool prior to heating.

[0057] In some illustrative examples, heating the composite layup includes applying directed heat to the composite layup while a sweep press of the forming machine compresses the composite layup against the tool (operation 518). In some illustrative examples, the directed heat may include at least one of infrared heaters above and / or below the layup, induction heaters above and / or below the layup, induction heating in the tool, an air blower, a conductive heater in the tool, or any other type of directed heater.

[0058] In some illustrative examples, method 500 seals the vacuum package against the tool (operation 520 ). In some illustrative examples, method 500 injects resin into the composite layup while sealing the vacuum package against the tool (operation 522 ).

[0059] In some illustrative examples, method 500 performs resin infusion on the composite layup within the vacuum package (operation 524). Resin infusion may be performed using any desired equipment. In some illustrative examples, additional tools or additional vacuum bags may be placed around the vacuum package.

[0060] In some illustrative examples, method 500 removes the composite layup having the formed shape from the vacuum encapsulation (operation 526). In some illustrative examples, the composite layup having the formed shape is removed from the vacuum encapsulation after the heat treatment. In some illustrative examples, the composite layup having the formed shape is removed from the vacuum encapsulation before the heat treatment.

[0061] In some illustrative examples, method 500 places the composite layup having the formed shape in at least one of the following ways: into a second tool; or onto a second tool (operation 528). In some illustrative examples, the second tool takes the form of a matching metal mold. In some illustrative examples, the second tool takes the form of a second mandrel. In some illustrative examples, the thermoplastic material takes the form of at least one of a thermoplastic veil or a thermoplastic suture (operation 530).

[0062] Now turn Figure 6 , depicts a flow chart of a method for forming a composite structure according to an illustrative embodiment. The method 600 may be performed to produce a composite part of the aircraft 100. The method 600 may be performed to Figure 2 The method 600 may include: Figure 3 The method 600 may be performed using the steps of the flowchart 300. Figure 4 The forming machine 402 is used to perform.

[0063] Method 600 compacts the composite layup within the vacuum package (operation 602). Method 600 shapes the composite layup on a tool while the composite layup is under vacuum within the vacuum package to produce a formed shape in the composite layup (operation 604). Method 600 processes the composite layup while in the formed shape (operation 606). Thereafter, method 600 terminates.

[0064] In some illustrative examples, forming the composite layup on the tool includes sweeping the composite layup on the tool with a forming machine (operation 608). The forming machine may include any desired type of sweeper to perform the sweeping. In some illustrative examples, the sweeper of the forming machine includes at least one of an inflatable bladder or a compliant scraper. In some illustrative examples, the compliant scraper includes a scraper, a finger, or any other desired type of sweeper.

[0065] In some illustrative examples, method 600 controls the vacuum applied to the composite layup to facilitate forming the composite layup (operation 610). By controlling the vacuum level within the vacuum package, the stiffness of the composite layup within the vacuum package can be controlled. By increasing the vacuum, the stiffness of the composite layup within the vacuum package can be increased. By decreasing the vacuum, the stiffness of the composite layup within the vacuum package can be decreased. In some illustrative examples, decreasing the vacuum reduces the stiffness, thereby making it easier to form the composite layup against the tool. In some illustrative examples, reducing the stiffness can allow the layers of the composite layup to slide more relative to each other.

[0066] In some illustrative examples, processing the composite layup includes resin infusing the composite layup having the formed shape within the vacuum package (operation 612). In some illustrative examples, processing the composite layup includes heating the composite layup to maintain the formed shape in the composite layup (operation 614). In some illustrative examples, heating the composite layup includes heating the composite layup while a squeegee holds the composite layup against the tool to maintain the formed shape of the composite layup. In some illustrative examples, heating the composite layup includes heating the composite layup on the tool using an oven. In some illustrative examples, heating the composite layup melts at least one of the thermoplastic veil or the thermoplastic suture.

[0067] In some illustrative examples, method 600 increases the vacuum in the vacuum package to maintain the formed shape after forming the composite layup on the tool (operation 616 ). Increasing the vacuum in the vacuum package increases the stiffness of the composite layup.

[0068] In some illustrative examples, processing the composite layup includes: removing the composite layup having the formed shape from the vacuum package; and placing the composite layup having the formed shape in at least one of the following ways: into a second tool; or onto the second tool (operation 618). The second tool can take any desired form. In some illustrative examples, the second tool can take the form of at least one of a matching metal die or a mandrel.

[0069] Now turn Figure 7 , depicts a flow chart of a method for forming a composite structure according to an illustrative embodiment. The method 700 may be performed to produce a composite part for the aircraft 100. The method 700 may be performed to Figure 2 The method 700 may include: Figure 3 The method 700 may be performed using the steps of the flowchart 300. Figure 4 The forming machine 402 is used to perform.

[0070] Method 700 loads a composite layup under vacuum in a vacuum package into a forming machine (operation 702). Method 700 sweeps the composite layup under vacuum in the vacuum package against a tool using a sweeper of the forming machine (operation 704). Thereafter, method 700 terminates.

[0071] In some illustrative examples, method 700 heats the composite layup while the scavenger holds the composite layup against the tool to maintain the formed shape of the composite layup (operation 706). In some illustrative examples, the composite layup is heated by a heating element integral to one of the former and the tool. In some illustrative examples, the composite layup is heated by a blower or other type of heater that is movable relative to the former.

[0072] In some illustrative examples, method 700 heats the composite layup on the tool using an oven (operation 708). In some illustrative examples, heating the composite layup melts at least one of the thermoplastic veil or the thermoplastic suture (operation 710). In some illustrative examples, melting at least one of the thermoplastic veil or the thermoplastic suture holds the composite layup together. In some illustrative examples, the thermoplastic veil reinforces the composite layup. In some illustrative examples, the thermoplastic suture provides adhesion and holds the composite layup together.

[0073] In some illustrative examples, method 700 injects resin into the composite layup in the vacuum package after sweeping the composite layup against the tool (operation 712). Resin injection can be performed using any desired equipment. In some illustrative examples, additional tools or additional vacuum bags can be placed around the vacuum package.

[0074] In some illustrative examples, the sweeper of the forming machine takes the form of an inflatable bladder or a compliant scraper, and wherein sweeping the composite layup under vacuum within the vacuum package against the tool includes sweeping the composite layup against the tool using the inflatable bladder or the compliant scraper to add pressure to reduce wrinkling during sweeping (operation 714).

[0075] Now turn Figure 8 , depicts a flow chart of a method for forming a composite structure according to an illustrative embodiment. The method 800 may be performed to produce a composite part of the aircraft 100. The method 800 may be performed to Figure 2 The method 800 may include: Figure 3 The method 800 may be performed using the steps of the flowchart 300. Figure 4 The forming machine 402 is used to perform.

[0076] Method 800 lays up layers of material to form a composite layup, the composite layup including at least one of a resin or a thermoplastic material (operation 802). Method 800 compacts the composite layup by applying a vacuum within a vacuum enclosure prior to forming (operation 804). Method 800 shapes the composite layup on a tool while the composite layup is under vacuum within the vacuum enclosure to produce a formed shape in the composite layup (operation 806). Method 800 heats the composite layup while under vacuum to maintain the formed shape in the composite layup by adhering the composite layup (operation 808). Method 800 then terminates.

[0077] In some illustrative examples, method 800 controls a vacuum applied to the composite layup to control slippage of material layers of the composite layup (operation 810). In some illustrative examples, the vacuum applied to the composite layup is reduced during forming of the composite layup to increase slippage of the material layers relative to each other.

[0078] In some illustrative examples, the thermoplastic material takes the form of at least one of a thermoplastic veil or a thermoplastic suture (operation 811). In some illustrative examples, method 800 sews the material layers together using the thermoplastic suture to form a composite layup before laying the material layers (operation 812). In some illustrative examples, the material layers are sewed into a plurality of separate suture groups. Each suture group can include any desired number of material layers.

[0079] In some illustrative examples, method 800 resin infuses the composite layup within the vacuum enclosure after the composite layup is formed (operation 814 ). In some illustrative examples, the vacuum enclosure is vacuum sealed to the tool before resin infusing the composite layup.

[0080] In some illustrative examples, shaping the composite layup includes sweeping the composite layup under vacuum within the vacuum encapsulation against the tool using a sweeper of the forming machine, wherein the sweeper of the forming machine takes the form of an inflatable bladder or a compliant scraper, and wherein sweeping the composite layup under vacuum within the vacuum encapsulation against the tool includes sweeping the composite layup against the tool using the inflatable bladder or the compliant scraper to apply pressure to reduce wrinkling during sweeping (operation 816). In some illustrative examples, the pressure within the inflatable bladder of the forming machine when shaping the composite layup under vacuum is greater than the pressure when shaping the composite prepreg not under vacuum.

[0081] As used herein, the phrase "at least one of" when used with a list of items means that different combinations of one or more of the listed items may be used, and only one of each item in the list may be required. For example, "at least one of" item A, item B, or item C" may include, but is not limited to, item A, item A and item B, or item B. This example may also include item A, item B, and item C, or item B and item C. Of course, any combination of these items may be present. In other examples, "at least one of" may be, for example, but not limited to, two of item A; one of item B; and ten of item C; four of item B and seven of item C; or other suitable combinations. The items may be specific objects, things, or categories. In other words, "at least one of" means that any combination of items and numbers of items from the list may be used, but not all items in the list are required to be used.

[0082] As used herein, "a plurality," when used with reference to items, means one or more items.

[0083] The flowcharts and block diagrams in the depicted different embodiments illustrate the architecture, functionality, and operation of some possible implementations of the devices and methods in the illustrative embodiments. In this regard, each box in the flowchart or block diagram can represent at least one of a module, segment, function, or portion of an operation or step.

[0084] In some alternative implementations of the illustrative embodiments, one or more functions indicated in the blocks may not occur in the order indicated in the accompanying drawings. For example, in some cases, two blocks shown in succession may be performed substantially simultaneously, or the blocks may sometimes be performed in the reverse order, depending on the functions involved. In addition, in addition to the blocks shown in the flowchart or block diagram, other blocks may be added. Some blocks may be optional. For example, operations 506 to 528 may be optional. For example, operations 608 to 620 may be optional. For example, operations 706 to 712 may be optional. For example, operations 810 to 816 may be optional.

[0085] You can Figure 9 Aircraft manufacturing and service method 900 is shown and Figure 10 Illustrative embodiments of the present disclosure are described in the context of aircraft 1000 as shown. Figure 9 , an illustration of an aircraft manufacturing and service method in the form of a block diagram is depicted in accordance with an illustrative embodiment. During pre-production, aircraft manufacturing and service method 900 may include Figure 10 Specification and design 902 of aircraft 1000 and material procurement 904.

[0086] During production, component and subassembly manufacturing 906 and system integration 908 of aircraft 1000 occurs. Thereafter, aircraft 1000 may undergo certification and delivery 910 for entry into service 912. While in operation 912 by a customer, aircraft 1000 is scheduled for routine maintenance and service 914, which may include modification, reconfiguration, refurbishment, or other maintenance and service.

[0087] Each of the processes of aircraft manufacturing and service method 900 may be performed or executed by a system integrator, a third party, and / or an operator. In these examples, the operator may be a customer. For purposes of this description, a system integrator may include, but is not limited to, any number of aircraft manufacturers and major system subcontractors; a third party may include, but is not limited to, any number of suppliers, subcontractors, and vendors; and an operator may include, but is not limited to, an airline, a leasing company, a military entity, a service organization, and the like.

[0088] Now refer to Figure 10 , depicts an illustration of an aircraft in block diagram form in which the illustrative embodiments may be implemented. In this example, aircraft 1000 is Figure 9 Aircraft manufacturing and service method 900 is produced and may include airframe 1002 having multiple systems 1004 and interior 1006. Examples of systems 1004 include one or more of propulsion system 1008, electrical system 1010, hydraulic system 1012, and environmental system 1014. Any number of other systems may be included.

[0089] Apparatus and methods embodied herein may be employed during at least one of the stages of aircraft manufacturing and service method 900. Figure 9 One or more illustrative embodiments are manufactured or used during at least one of component and subassembly manufacturing 906 , system integration 908 , operation 912 , or maintenance and service 914 .

[0090] Illustrative examples utilize vacuum forming in a novel process for dry materials. A vacuum bag is used to remove bulk from a composite layup, such as a dry laminate. The composite layup is formed against a tool. In some illustrative examples, the composite layup can be formed using a forming machine. In some illustrative examples, the forming machine can use an inflatable bladder to increase pressure to reduce wrinkling and further control bulk.

[0091] An illustrative example controls wrinkle and volumetric behavior of a composite material used in a forming process. The illustrative example controls wrinkle and volumetric behavior during subsequent operations after forming a composite layup onto a mandrel under vacuum. For example, the illustrative example also controls wrinkle and volumetric behavior during subsequent operations in a process utilizing a closed mold tool. With a closed mold tool, volumetric control can be tightly controlled to allow the tool to close and prevent or reduce inconsistent areas.

[0092] In illustrative examples, a vacuum bag encapsulating the composite layup is used in conjunction with a sweeper that applies pressure to achieve an elevated pressure exceeding the vacuum pressure. In some illustrative examples, the forming pressure is applied by an inflatable bladder in the layup machine. In some illustrative examples, integrated heating during the forming process is used to further assist in volume control. In other illustrative examples, heat can be applied to the composite layup after forming. Elevated pressure during forming is used to control wrinkles and volume. Temperature control can be used to bond the material at least one of during or after forming, and subsequently reduce volume / thickness.

[0093] The present disclosure relates to exemplary embodiments defined in the following terms.

[0094] Clause 1. A method 500 of forming 246, 306 a composite structure, the method comprising:

[0095] sealing 502 the composite layup 202 , 408 including at least one of the resin 221 or the thermoplastic material 216 in the vacuum package 208 ; and

[0096] The composite layup 202 , 408 is formed 246 , 306 , 504 on the tool 204 , 406 to create the formed shape 222 in the composite layup 202 , 408 while the composite layup 202 , 408 is maintained under the vacuum 206 in the vacuum enclosure 208 .

[0097] Clause 2. The method 500 of clause 1, further comprising:

[0098] The level of the vacuum 206 in the vacuum enclosure 208 is varied 510 during the forming 246 , 306 of the composite layup 202 , 408 on the tool 204 , 406 to control the forming 246 , 306 of the composite layup 202 , 408 .

[0099] Clause 3. The method 500 of clause 1, further comprising:

[0100] The composite layup 202 , 408 is heated 250 , 314 , 512 while under the vacuum 206 to maintain the formed shape 222 in the composite layup 202 , 408 .

[0101] Clause 4. The method 500 of Clause 3, wherein heating 250 , 314 the composite layup 202 , 408 514 includes melting at least one of the thermoplastic veil 218 or the thermoplastic suture 220 in the composite layup 202 , 408 .

[0102] Clause 5. The method 500 of Clause 3, wherein heating 516 250 , 314 the composite layup 202 , 408 comprises heating 250 , 314 the composite layup 202 , 408 on the tool 204 , 406 in an oven 232 .

[0103] Clause 6. The method 500 of clause 3, wherein heating 518 250 , 314 the composite layup 202 , 408 comprises applying directed heat to the composite layup 202 , 408 while a scavenger 228 , 404 of a former 226 , 402 compresses the composite layup 202 , 408 against the tool 204 , 406 .

[0104] Clause 7. The method 500 of clause 1, further comprising:

[0105] sealing 520 the vacuum enclosure 208 against the tool 204 , 406 ; and

[0106] Resin 234 is injected 522 into the composite layup 202 , 408 while simultaneously sealing the vacuum package 208 against the tool 204 , 406 .

[0107] Clause 8. The method 500 of clause 1, further comprising:

[0108] The composite layup 202 , 408 sealed in the vacuum package 208 is loaded 508 into a former 226 , 402 , wherein forming 246 , 306 the composite layup 202 , 408 on the tool 204 , 406 is performed by sweeping the composite layup 202 , 408 over the tool 204 , 406 by the former 226 , 402 .

[0109] Clause 9. The method 500 of clause 1, further comprising:

[0110] Resin is injected 236 , 524 into the composite layup 202 , 408 within the vacuum package 208 .

[0111] Clause 10. The method 500 of clause 1, further comprising:

[0112] The composite layup 202 , 408 is densified 244 , 506 prior to the forming 246 , 306 by applying the vacuum 206 within the vacuum encapsulation 208 prior to the forming 246 , 306 .

[0113] Clause 11. The method 500 of clause 1, further comprising:

[0114] removing 526 the composite layup 202 , 408 having the formed shape 222 from the vacuum package 208 ; and

[0115] Positioning 528 the composite layup 202 , 408 having the formed shape 222 in at least one of the following ways:

[0116] Place 528 into second tool 238; or

[0117] Place 528 onto second tool 238 .

[0118] Clause 12. The method 500 of Clause 1, wherein the thermoplastic material 216 is in the form of at least one of a thermoplastic veil 218 or a thermoplastic suture 220.

[0119] Clause 13. A method 600 of forming a composite layup 202, 408 with reduced wrinkling, the method comprising:

[0120] compacting 244 , 602 the composite stack 202 , 408 in a vacuum package 208 ;

[0121] forming 246 , 306 , 604 the composite layup 202 , 408 on a tool 204 , 406 to produce a formed shape 222 in the composite layup 202 , 408 while the composite layup 202 , 408 is under the vacuum 206 within the vacuum enclosure 208 ; and

[0122] The composite layup 202 , 408 is processed 248 , 606 while in the formed shape 222 .

[0123] Clause 14. The method 600 of Clause 13, wherein processing 248 the composite layup 202 , 408 612 includes infusing resin 234 into the composite layup 202 , 408 having the formed shape 222 within the vacuum package 208 .

[0124] Clause 15. The method 600 of Clause 13, wherein forming 608 the composite layup 202 , 408 on the tool 204 , 406 246 , 306 comprises sweeping the composite layup 202 , 408 on the tool 204 , 406 with a former 226 , 402 .

[0125] Clause 16. The method 600 of Clause 13, wherein processing 248 the composite layup 202 , 408 614 includes heating 250 , 314 the composite layup 202 , 408 to maintain the formed shape 222 in the composite layup 202 , 408 .

[0126] Clause 17. The method 600 of clause 13, further comprising:

[0127] After forming 246 , 306 the composite layup 202 , 408 on the tool 204 , 406 , the vacuum 206 in the vacuum enclosure 208 is increased 616 to maintain the formed shape 222 .

[0128] Clause 18. The method 600 of clause 13, further comprising:

[0129] The vacuum 206 applied to the composite layup 202 , 408 is controlled 610 to facilitate the forming 246 , 306 of the composite layup 202 , 408 .

[0130] Clause 19. The method 700 of clause 13, wherein 618 processing 248 the composite layup 202, 408 comprises:

[0131] removing the composite layup 202 , 408 having the formed shape 222 from the vacuum package 208 ; and

[0132] Positioning 238 the composite layup 202 , 408 having the formed shape 222 in at least one of the following ways:

[0133] Placed into the second tool 204, 406; or

[0134] Placed onto the second tool 204 , 406 .

[0135] Clause 20. A method 700 of forming 246, 306 a composite layup 202, 408, the method comprising:

[0136] loading 702 the composite layup 202 , 408 under vacuum 206 within the vacuum package 208 into the forming machine 226 , 402 ; and

[0137] The composite layup 202 , 408 under the vacuum 206 within the vacuum enclosure 208 is swept 704 against the tool 204 , 406 using the sweeper 228 , 404 of the former 226 , 402 .

[0138] Clause 21. The method 700 of clause 20, further comprising:

[0139] The composite layup 202 , 408 is heated while the sweep press 228 , 404 holds the composite layup 202 , 408 against the tool 204 , 406 to maintain the formed shape 222 of the composite layup 202 , 408 .

[0140] Clause 22. The method 700 of clause 20, further comprising:

[0141] The composite layup 202 , 408 on the tool 204 , 406 is heated 708 using the oven 232 .

[0142] Clause 23. The method 700 of Clause 20, wherein heating 710 the composite laminate 202, 408 melts at least one of the thermoplastic veil 218 or the thermoplastic suture 220.

[0143] Clause 24. The method 700 of clause 20, further comprising:

[0144] After sweeping the composite layup 202 , 408 against the tool 204 , 406 , resin 234 is injected 236 , 712 into the composite layup 202 , 408 in the vacuum package 208 .

[0145] Clause 25. The method 700 of clause 20, wherein the sweeper 228, 404 of the former 226, 402 is in the form of an inflatable bladder 229 or a compliant scraper 231, and wherein sweeping the composite laminate 202, 408 under the vacuum 206 within the vacuum package 208 against the tool 204, 406 includes sweeping the composite laminate 202, 408 against the tool 204, 406 using the inflatable bladder 229 or the compliant scraper 231 to add pressure to reduce wrinkling during the sweeping.

[0146] Clause 26. A method 800 of forming 246, 306 a composite layup 202, 408, the method comprising:

[0147] laying up 802 the layers 252 of the material 254 to form a composite layup 202 , 408 including at least one of the resin 221 or the thermoplastic material 216 ;

[0148] Prior to forming 246 , 306 , compacting 244 , 804 the composite layup 202 , 408 by applying a vacuum 206 within the vacuum package 208 ;

[0149] forming 246 , 306 , 806 the composite layup 202 , 408 on a tool 204 , 406 while the composite layup 202 , 408 is under the vacuum 206 within the vacuum enclosure 208 to produce a formed shape 222 in the composite layup 202 , 408 ;

[0150] The composite layup 202 , 408 is heated 250 , 314 , 808 while in the vacuum 206 to maintain the formed shape 222 in the composite layup 202 , 408 by adhering the composite layup 202 , 408 .

[0151] Clause 27. The method 800 of clause 26, further comprising:

[0152] The vacuum 206 applied to the composite layup 202 , 408 is controlled 810 to control slippage of the layer 252 of material 254 of the composite layup 202 , 408 .

[0153] Clause. The method 800 of clause 26, further comprising:

[0154] After the composite layup 202 , 408 is formed, resin is injected 236 , 814 into the composite layup 202 , 408 within the vacuum enclosure 208 .

[0155] Clause 29. The method 800 of clause 26, wherein forming the composite stack 816 comprises sweeping 704 the composite stack 202, 408 under vacuum 206 within the vacuum package 208 against a tool 204, 406 using a sweeper 228, 404 of a forming machine 226, 402, wherein the sweeper 228, 404 of the forming machine 226, 402 is in the form of an inflatable bladder 229 or a compliant scraper 231, and wherein sweeping 704 the composite stack 202, 408 under vacuum 206 within the vacuum package 208 against a tool 204, 406 comprises sweeping 704 the composite stack 202, 408 against the tool 204, 406 using the inflatable bladder 229 or the compliant scraper 231 to add pressure to reduce wrinkling during the sweeping.

[0156] Clause 30. The method 800 of Clause 26, wherein the thermoplastic material 216 takes the form of at least one of a thermoplastic veil 218 or a thermoplastic suture 220.

[0157] Clause 31. The method 800 of clause 30, further comprising:

[0158] Prior to laying up 802 the layers 252 of the material 254 to form the composite layup 202 , 408 , the layers 252 of the material 254 are stitched 812 together using the thermoplastic stitching 220 .

[0159] The description of the various illustrative embodiments has been presented for purposes of illustration and description and is not intended to be exhaustive or limited to the embodiments in the disclosed form. Many modifications and variations will be apparent to those skilled in the art. Furthermore, different illustrative embodiments may provide different features than other illustrative embodiments. The selected embodiment or embodiments are chosen and described in order to best explain the principles of the embodiments, their practical application, and to enable those skilled in the art to understand that the present disclosure can be used in a variety of embodiments with various modifications suitable for the specific use contemplated.

Claims

1. A method (500) of forming a composite structure (246, 306), the method comprising: sealing (502) a composite layup (202, 408) in a vacuum package (208), the composite layup (202, 408) comprising at least one of a resin (221) or a thermoplastic material (216); as well as The composite layup (202, 408) is formed (246, 306, 504) on a tool (204, 406) to produce a formed shape (222) in the composite layup (202, 408) while the composite layup (202, 408) is maintained under a vacuum (206) in the vacuum enclosure (208).

2. The method (500) of claim 1, further comprising: The level of vacuum (206) in the vacuum enclosure (208) is varied (510) during forming (246, 306) of the composite layup (202, 408) on the tool (204, 406) to control the forming (246, 306) of the composite layup (202, 408).

3. The method (500) of claim 1, further comprising: The composite layup (202, 408) is heated (250, 314, 512) while under vacuum (206) to maintain the formed shape (222) in the composite layup (202, 408).

4. The method (500) according to claim 3, wherein: Heating (250, 314) the composite laminate (202, 408) includes melting at least one of a thermoplastic veil (218) or a thermoplastic suture (220) in the composite laminate (202, 408).

5. The method (500) of claim 3, wherein: Heating (250, 314) the composite layup (202, 408) includes heating (250, 314) the composite layup (202, 408) on the tool (204, 406) in an oven (232).

6. The method (500) of claim 3, wherein: Heating (250, 314) the composite layup (202, 408) includes applying directed heat to the composite layup (202, 408) while a sweeper (228, 404) of a forming machine (226, 402) compresses the composite layup (202, 408) against the tool (204, 406).

7. The method (500) of claim 1, further comprising: sealing (520) the vacuum package (208) against the tool (204, 406); and Resin (234) is injected (522) into the composite layup (202, 408) while sealing the vacuum package (208) against the tool (204, 406).

8. A method (600) of forming a composite layup (202, 408) with reduced wrinkling, the method comprising: compacting (244, 602) the composite laminate (202, 408) in a vacuum package (208); forming (246, 306, 604) the composite layup (202, 408) on a tool (204, 406) while the composite layup (202, 408) is under a vacuum (206) within the vacuum enclosure (208) to produce a formed shape (222) in the composite layup (202, 408); as well as The composite layup (202, 408) is processed (248, 606) while in the formed shape (222).

9. A method (700) of forming (246, 306) a composite layup (202, 408), the method comprising: loading (702) the composite layup (202, 408) under vacuum (206) within the vacuum package (208) into a forming machine (226, 402); as well as The composite layup (202, 408) under vacuum (206) within the vacuum package (208) is swept (704) against a tool (204, 406) using a sweeper (228, 404) of the former (226, 402).

10. A method (800) of forming (246, 306) a composite layup (202, 408), the method comprising: laying down (802) layers (252) of material (254) to form a composite layup (202, 408) comprising at least one of a resin (221) or a thermoplastic material (216); prior to forming (246, 306), compacting (244, 804) the composite layup (202, 408) by applying a vacuum (206) within a vacuum enclosure (208); forming (246, 306, 806) the composite layup (202, 408) on a tool (204, 406) while the composite layup (202, 408) is under a vacuum (206) within the vacuum enclosure (208) to produce a formed shape (222) in the composite layup (202, 408); The composite layup (202, 408) is heated (250, 314, 808) while under vacuum (206) to maintain the formed shape (222) in the composite layup (202, 408) by adhering the composite layup (202, 408).

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