Patent Description:
Ply-by-Ply (PBP) forming machines (also known as "single ply forming machines") apply forces that compact unhardened plies (uncured or unconsolidated) of composite material onto forming tools (e.g., mandrels) in order to fabricate preforms for composite parts. Compaction ensures that a ply is made physically integral with the underlying preform, and also ensures that the preform conforms with desired standards for shape and size before it is hardened (e.g., cured or consolidated) into a composite part.

Plies used by PBP forming machines may be cut from broadgood sheets of continuous fiber-reinforced material. Cutting plies from a broadgood sheet results in an undesirable amount of material in each broadgood sheet being wasted. This issue is particularly notable in the aerospace industry because thermoset materials are particularly expensive to purchase, store, and maintain. Furthermore, complex contours for composite parts, such as those found in the aerospace industry, may further increase the amount of waste.

Another issue related to PBP forming techniques is that during compaction, PBP forming machines apply shearing forces that press a ply into shape. The shearing forces have the potential to undesirably stretch or distort the ply, depending on the orientation of fibers within the ply. If distorting or stretching occurs beyond a predetermined tolerance, the entire preform may be discarded or reworked. Furthermore, because fiber orientation is dictated by design constraints, it is not desirable to alter fiber orientations of plies to address this fabrication concern.

A still further issue with PBP forming is that it is particularly slow. PBP forming requires a great deal of labor in support of ply kitting, ply sorting and transfer, placing plies on a carrier or forming tool (e.g., mandrel), and performing film removal. This causes PBP forming to be particularly expensive as a fabrication technique for composite parts, which is undesirable. For example, current methods of cutting material from broadgoods, and the lack of efficient techniques of fabricating plies and transferring them to a preform or forming tool (e.g., mandrel), require substantial human interaction.

In addition, during fabrication, a wing panel of an aircraft may be assembled at one cell, and then may be transported to a new cell where stringers are installed onto the wing panel. While the fabrication processes discussed above are reliable, they encounter delays when work at a specific portion of a wing panel is completed more slowly than expected. For example, if a particular aspect of stringer preform placement upon a wing panel takes longer than expected, then the wing panel cannot progress to a next cell until the work is completed. Alternatively, placement of a stringer preform may be completed after the wing panel has progressed to the next cell, but this out of position work requires specialized tooling to be moved into place and operated in order to perform placement of the missing stringer. This work necessarily obstructs some or all of the work planned for the next cell. Consequently, delays in stringer placement typically cause a wing panel to stay in a stringer placement cell longer than desired, which may impede progress on an assembly line.

Patent document <CIT>, according to its abstract, states: a method for manufacture of a torsion-box type skin composite structure mountable to a main sub-structure, the torsion-box type skin composite structure comprises a skin component, a stiffener element, a fastener element for bonding the torsion-box type skin composite structure to the main sub-structure. The method comprises the step of providing a forming tool, providing a skin lay-up onto the forming tool, positioning a stiffener lay-up and a fastener lay-up to the skin lay-up for forming an integral lay-up and co-curing the integral lay-up, and mounting a coupling member to the stiffener element and the fastener element.

Patent document <CIT>, according to its abstract, states: a self-stiffened panel of preimpregnated composite. The panel is of a type comprised of a base skin on one side of which are added and placed side-by-side U-shaped stiffeners of which the parts connecting the branches of the U are flattened against the skin, with an interfacing structure between the adjoining branches of two adjacent stiffeners The interfacing structure is a nail having a nail-head comprised of a cord of filling resin, the nail formed from a band with a rectangular cross-section whose edge, on the skin side, is directly in contact with the adjoining surface of the skin. The nail-head is comprised of two half-nail-heads placed symmetrically in the angle formed between the skin and the nail.

Patent document <CIT>, according to its abstract, states: a process for manufacturing panels for aeronautical structures with U-shaped stiffening members and I-shaped stiffening members between their webs comprising the steps of providing laminates for shaping the skin on the curing tool, providing planar laminates for shaping the stiffening members, shaping the U-shaped stiffening members on individual shaping tools and placing the I-shaped stiffening elements in the tools, grouping the individual shaping tools together on an assembly tool, placing the group of stiffening members on the skin, placing a vacuum bag on the assembly with the aid of profiles, consolidating the assembly by means of a curing process under suitable pressure and temperature conditions using external tools to assure verticality of the webs of the stiffening members.

Embodiments described herein fabricate tows from multiple lanes of unhardened fiber reinforced composite materials. The lanes are placed side-by-side to form a multi-lane tow comprising segments of separately laid-up fiber reinforced material. This eliminates the need to cut entire plies from a broadgood sheet of material and reduces waste, which reduces "Buy to Fly" costs. A release film is placed against the multi-lane tow. The release film bears shear stresses applied by a PBP machine, and enhances the ability of the multi-lane tow to bear load. Embodiments described herein may further stack plies at a multi-lane tow to form a multi-lane tow having multiple layers. One advantage is to stabilize the physical structure of the multi-lane tow to increase its resistance to shear forces applied during PBP forming processes. PBP forming of stack plies also increase the throughput of the machine because fewer forming steps are required to fabricate the composite part.

One embodiment is a method for preparing a preform for hardening into a composite part. The method includes dispensing a first set of lanes, that each comprise a tow of fiber-reinforced material, at a first angle such that the lanes are placed side-by-side with respect to each other, forming a first layer of a multi-lane tow. The method further includes applying a film directly in contact with multi-lane tow that resists shear forces applied to the multi-lane tow, transporting the multi-lane tow to a forming tool (e.g., mandrel), and compacting the multi-lane tow via a Ply-By-Ply (PBP) machine disposed at the forming tool (e.g., mandrel). The method further comprises removing the film from the multi-lane tow.

A further embodiment is a non-transitory computer readable medium embodying programmed instructions which, when executed by a processor, are operable for performing a method for preparing a preform for hardening into a composite part. The method includes dispensing a first set of lanes, that each comprise a tow of fiber-reinforced material, at a first angle such that the lanes are placed side-by-side with respect to each other, forming a first layer of a multi-lane tow. The method further includes applying a film directly in contact with multi-lane tow that resists shear forces applied to the multi-lane tow, transporting the multi-lane tow to a forming tool (e.g., mandrel), and compacting the multi-lane tow via a Ply-By-Ply (PBP) machine disposed at the forming tool (e.g., mandrel). The method further comprises removing the film from the multi-lane tow.

A further embodiment is an apparatus for preparing a preform for hardening into a composite part. The apparatus includes multiple tape dispensing heads that each dispense a tow of fiber-reinforced material to form a multi-lane tow, an end effector that applies a film directly in contact with the multi-lane tow, a Pick-and-Place (PNP) machine that transports the multi-lane tow, and a Ply-By-Ply (PBP) machine that compacts the multi-lane tow onto a preform.

Embodiments described herein also provide for enhanced placement of preforms for stringers onto a wing panel preform in an assembly environment.

One embodiment is a method for placing a stringer preform upon a wing panel preform. The method includes creating a wing panel preform upon a layup forming tool (e.g., mandrel), and applying stringer preforms to the wing panel preform in a single batch placement.

Another embodiment is a method for placing a stringer preform upon a wing panel preform. The method includes creating a wing panel preform upon a layup forming tool (e.g., mandrel), creating stringer preforms that each include a blade, and placing each of the stringer preforms onto the wing panel preform while maintaining a constant, uniform angle shared between the blades.

Another embodiment is a method for placing a stringer preform upon a wing panel preform. The method includes creating a wing panel preform upon a layup forming tool (e.g., mandrel), pulsing the wing panel preform through a series of stations, and applying stringer preforms to the wing panel preform at each station while the wing panel preform progresses through the stations.

A further embodiment is a method for splicing stringer preforms. The method includes creating a wing panel preform upon a layup forming tool (e.g., mandrel), creating stringer preform sections, placing a first stringer preform section upon the wing panel preform, and splicing a second stringer preform section to the first stringer preform section.

A further embodiment is an apparatus for an aircraft assembly. The apparatus includes a wing panel preform, and a first stringer preform section spliced to a second stringer preform section upon the wing panel preform.

Other illustrative embodiments (e.g., methods, apparatus and computer-readable media relating to the foregoing embodiments) may be described below. The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings.

The figures and the following description provide specific illustrative embodiments of the disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the disclosure and are included within the scope of the disclosure. Furthermore, any examples described herein are intended to aid in understanding the principles of the disclosure, and are to be construed as being without limitation to such specifically recited examples and conditions. As a result, the disclosure is not limited to the specific embodiments or examples described below, but by the claims.

Composite parts, such as Carbon Fiber Reinforced Polymer (CFRP) parts, are laid-up in multiple layers that together are referred to as a preform. Individual fibers within each layer of the preform are aligned parallel with each other, but different layers may exhibit different fiber orientations in order to increase the strength of the resulting composite part along different dimensions. The preform may include a viscous resin that solidifies in order to harden the preform into a composite part (e.g., for use in an aircraft). Carbon fiber that has been impregnated with an uncured thermoset resin or a thermoplastic resin is referred to as "prepreg. " Other types of carbon fiber include "dry fiber" which has not been impregnated with thermoset resin but may include a tackifier or binder. Dry fiber may be infused with resin prior to hardening or curing. For thermoset resins, the hardening is a one-way process referred to as curing, while for thermoplastic resins, the resin may reach a viscous form if it is re-heated.

<FIG> is a block diagram of a fabrication environment <NUM> in an illustrative embodiment. Fabrication environment <NUM> includes fabrication system <NUM>, which creates a multi-lane tow <NUM> via tape dispensing array <NUM>, places the multi-lane tow <NUM> onto a mandrel <NUM> (or preform <NUM>) via Pick-and-Place (PNP) machine <NUM>, and compacts the multi-lane tow <NUM> into place via PBP machine <NUM> (also referred to herein as a "PBP forming machine" or "single ply forming machine"). Here, the term "tow" refers to any width of unhardened composite material which can be spooled and dispensed for automated placement. Widths of tow may vary, in the range of <NUM> (one eighth of an inch) up to <NUM> (six inches) or more, depending on the application and design of the composite part.

In this embodiment, tape dispensing array <NUM> comprises spools <NUM> which store continuous lengths of unidirectional fiber-reinforced material. Other fiber reinforced material forms may include woven fiber fabric or discontinuous fiber mat. Cartridges <NUM> adjust an angle of the heads <NUM> with respect to layup surface <NUM>, and heads <NUM> physically dispense lanes <NUM> of fiber reinforced material from the spools <NUM> to form the multi-lane tow <NUM> onto the layup surface <NUM>. Controller <NUM> manages the operations of tape dispensing array <NUM> (e.g., to control the cartridges <NUM> and to adjust an angle of heads <NUM>), and may also coordinate the motion of shuttle <NUM> relative to tape dispensing array <NUM>. Because tape dispensing array <NUM> fabricates the multi-lane tow <NUM> from multiple lanes of fiber reinforced material, there is no need to cut plies from a broadgood sheet of fiber reinforced material, and the amount of waste involved in fabrication is reduced. Furthermore, because there are multiple heads <NUM> which are used to perform layup (e.g., one per lane), the speed of fabrication is beneficially increased.

PNP machine <NUM> dispenses the film <NUM> (e.g., a layer of Fluorinated Ethylene Propylene (FEP), a layer of Ethylene Tetrafluoroethylene (ETFE), etc.) onto multi-lane tow <NUM>, and may physically pick up and place the multi-lane tow <NUM> onto a layer <NUM> of preform <NUM>, or onto the mandrel <NUM>. In this embodiment, PNP machine <NUM> includes end effector <NUM> and vacuum system <NUM>, which together operate in accordance with instructions from a Numerical Control (NC) program stored in a memory of controller <NUM>. Film <NUM> includes an engineered surface <NUM> (e.g., a textured surface) that contacts the multi-lane tow <NUM> and facilitates tack to the multi-lane tow <NUM>, and further includes an engineered surface <NUM> (e.g., a smooth surface) that contacts the PBP machine <NUM> during compaction. The engineered surface <NUM> facilitates sliding of an element <NUM> (or a nose piece, or air bladder) of the PBP machine <NUM> along the film <NUM>.

In this embodiment, PBP machine <NUM> includes spreader arms <NUM>, which together pull the element <NUM> taut against the preform <NUM> to compact the preform <NUM> against mandrel <NUM> while stomp feet <NUM> hold a center portion of preform <NUM> in place to prevent translation of preform <NUM>. Actions performed by PBP machine <NUM> are managed by controller <NUM>.

In further embodiments, the PBP machine <NUM> includes a nose or an air bladder that is controlled to follow a preform or mandrel shape from the stomp foot to the edge of part. This operation is performed similarly to the operation of smoothing a bedsheet by sliding one's hand across the surface. Thus, the preform <NUM> is tensioned by sliding the element <NUM> along the surface starting from the stomp foot outward, with any wrinkles being smoothed out. This action physically forms the ply against the preform or mandrel.

In further embodiments different types of PBP machines <NUM> may be utilized. For example, in further embodiments, the PBP machine <NUM> includes a nose or an air bladder that is controlled to follow a preform or mandrel shape from a stomp foot to an edge of the preform. This operation is performed similarly to the operation of smoothing a bedsheet by sliding one's hand across the surface. This action physically forms the ply into a desired shape.

<FIG>, shows a block diagram of a fabrication environment 100A in a further illustrative embodiment. In this embodiment, the PNP machine <NUM> first dispenses the film <NUM> (e.g., a layer of Fluorinated Ethylene Propylene (FEP), a layer of Ethylene Tetrafluoroethylene (ETFE), etc.) onto the layup surface <NUM> of the shuttle <NUM>. The film <NUM> is dispensed such that engineered surface <NUM> is positioned downward and contacts the shuttle <NUM> and engineered surface <NUM> is positioned upward for subsequent dispensing of fiber reinforced material.

In this embodiment, cartridges <NUM> adjust an angle of the heads <NUM> with respect to layup surface <NUM>, and heads <NUM> physically dispense lanes <NUM> of fiber reinforced material from the spools <NUM> to form the multi-lane tow <NUM> onto the engineered surface <NUM> of the film <NUM>. Controller <NUM> manages the operations of tape dispensing array <NUM> (e.g., to control the cartridges <NUM> and to adjust an angle of heads <NUM>), and may also coordinate the motion of shuttle <NUM> relative to tape dispensing array <NUM>.

Illustrative details of the operation of fabrication environment <NUM> and 100a will be discussed with regard to <FIG> and <FIG>. Assume, for these embodiments, that mandrel <NUM> awaits receipt of multi-lane tows <NUM> that will be compacted together to result in the preform <NUM>.

<FIG> is a flowchart illustrating a method <NUM> for creating a multi-lane tow and its use with a PBP machine <NUM> in an illustrative embodiment. The steps of method <NUM> are described with reference to fabrication system <NUM> of <FIG>, but those skilled in the art will appreciate that method <NUM> may be performed in other systems. The steps of the flowcharts described herein are not all inclusive and may include other steps not shown. The steps described herein may also be performed in an alternative order.

In step <NUM>, controller <NUM> operates tape dispensing array <NUM> to dispense a first set of lanes <NUM> of unidirectional fiber-reinforced material. The lanes are disposed at a first angle such that they are placed side-by-side with respect to each other, forming a first layer of a multi-lane tow <NUM>. As used herein, lanes that are placed "side-by-side" are disposed such that their sides (i.e., the edges that are neither the leading edge nor the trailing edge during dispensing) contact each other or include a nominal gap, but do not overlap.

In further embodiments, the multi-lane tow <NUM> may be shuttled via shuttle <NUM> along its length, and a second set of lanes <NUM> may be dispensed atop the first layer at a second angle such that the second set of lanes are placed side-by-side with respect to each other. This forms a second layer of the multi-lane tow <NUM> that has the same or a different fiber orientation than the first layer. A multi-lane tow <NUM> that comprises multiple layers having a variety of fiber orientations may be particularly resilient when resisting shear forces applied by a PBP machine <NUM> during compaction.

In step <NUM>, controller <NUM> operates PNP machine <NUM> to apply a film <NUM> directly in contact with, and specifically atop the multi-lane tow <NUM>. This may comprise placing engineered surface <NUM> against multi-lane tow <NUM>, and pressing the film <NUM> into place. The film <NUM> enhances physical integrity of the multi-lane tow <NUM> during PNP operations, and further resists shear forces applied during PBP forming. The film may additionally facilitate sliding of element <NUM> across the multi-lane tow <NUM>.

In step <NUM>, controller <NUM> operates the PNP machine <NUM> to transport the multi-lane tow <NUM> and the film <NUM> to a PBP machine <NUM> (e.g., via action of the vacuum system <NUM> in combination with end effector <NUM>. This may comprise gripping the film <NUM> and the multi-lane tow <NUM> via suction, moving these components to the preform <NUM>, and releasing these components.

In step <NUM>, the PBP machine <NUM> compacts the multi-lane tow <NUM> onto preform <NUM>. In one embodiment, the PBP machine <NUM> performs this task by spreading the spreader arms <NUM> while stomp feet <NUM> hold preform <NUM> and multi-lane tow <NUM> in place. This action presses an element <NUM> (e.g., a veil, a nose piece, or an air bladder) against the multi-lane tow <NUM>, compacting it into a desired shape and making it integral with preform <NUM>. In further embodiments, a nose piece or air bladder of the PBP machine <NUM> performs a similar role. During compaction, film <NUM>, positioned between element <NUM> and the multi-lane tows <NUM>, bears shear stresses that are applied via the element <NUM>. The film <NUM> also holds the multi-lane tow together during PNP and PBP operations, operating as a backing material.

The compaction process performed by the PBP machine <NUM> may result in a stringer having any desired cross-sectional shape, depending on the shape of the mandrel <NUM>. Examples of such shapes include angles (L or similar cross section), hat shapes (e.g., rounded or trapezoidal hat shapes, C-shapes, and others.

In step <NUM>, PNP machine <NUM> removes the film <NUM> from the multi-lane tow <NUM>, for example, by pulling the film <NUM> off of multi-lane tow <NUM>. Because multi-lane tow <NUM> has been compacted onto the preform <NUM>, the force required to remove the film <NUM> from the multi-lane tow <NUM> is less than the force required to remove the multi-lane tow <NUM> from the preform <NUM>. The film <NUM> may be removed by peeling the film <NUM> from an end or corner.

Steps <NUM>-<NUM> may be repeated as desired. For example, the steps of dispensing, applying, transporting, compacting, and removing may be iteratively performed to fabricate, place, and compact multiple multi-lane tows <NUM> onto a preform <NUM> to increase a size (e.g., a thickness or length, or both) thickness of the preform.

<FIG> is a flowchart illustrating a further embodiment, method 200A, for creating a multi-lane tow <NUM>, and as well as use of a multi-lane tow <NUM> with a PBP machine <NUM> in an illustrative embodiment. The steps of method 200A are described with reference to fabrication system <NUM> of <FIG>, but those skilled in the art will appreciate that method 200A may be performed in other systems. The steps of the flowcharts described herein are not all inclusive and may include other steps not shown. The steps described herein may also be performed in an alternative order.

In step 202A, controller <NUM> operates PNP machine <NUM> to apply a film <NUM> to the layup surface <NUM> of the shuttle <NUM>. This may comprise placing engineered surface <NUM> of film <NUM> against the layup surface <NUM> of shuttle <NUM> and pressing the film <NUM> into place. The film <NUM> will be in direct contact with the multi-lane tow and will enhance physical integrity of the multi-lane tow <NUM> during PNP operations, and further resists shear forces applied during PBP forming. The film may additionally facilitate sliding of element <NUM> across the multi-lane tow <NUM>.

In step 204A, controller <NUM> operates tape dispensing array <NUM> to dispense a first set of lanes <NUM> of unidirectional fiber-reinforced material onto the engineered surface <NUM> of the film <NUM>. The lanes are disposed at a first angle such that they are placed side-by-side with respect to each other, forming a first layer of a multi-lane tow <NUM>. As used herein, lanes that are placed "side-by-side" are disposed such that their sides (i.e., the edges that are neither the leading edge nor the trailing edge during dispensing) contact each other or include a nominal gap, but do not overlap.

In further embodiments, the multi-lane tow <NUM> may be shuttled via shuttle <NUM> along its length, and a second set of lanes <NUM> may be dispensed atop the first layer at a second angle such that the second set of lanes are placed side-by-side with respect to each other. This forms a second layer of the multi-lane tow that has the same or a different fiber orientation than the first layer. A multi-lane tow <NUM> that comprises multiple layers having a variety of fiber orientations may be particularly resilient when resisting shear forces applied by a PBP machine during compaction.

In step 206A, controller <NUM> operates the PNP machine <NUM> to transport the multi-lane tow <NUM> and the film <NUM> to a PBP machine <NUM> (e.g., via action of the vacuum system <NUM> in combination with end effector <NUM>. This may comprise gripping the film <NUM> and the multi-lane tow <NUM> via suction, moving these components to the preform <NUM>, and releasing these components. In this embodiment, the film <NUM> and the multi-lane tow <NUM> may be flipped, inverted, or otherwise positioned such that the multi-lane tow <NUM> is held in contact with the preform <NUM> at the PNP machine <NUM>.

In step 208A, the PBP machine <NUM> compacts the multi-lane tow <NUM> onto preform <NUM>. In one embodiment, the PBP machine <NUM> performs this task by spreading the spreader arms <NUM> while stomp feet <NUM> hold preform <NUM> and multi-lane tow <NUM> in place. This action presses an element <NUM> (e.g., a veil, a nose piece, or an air bladder) against multi-lane tow <NUM>, compacting it into a desired shape and making it integral with preform <NUM>. In further embodiments, a nose piece or air bladder of the PBP machine <NUM> performs a similar role. During compaction, film <NUM>, positioned between element <NUM> and the multi-lane tows <NUM>, bears shear stresses that are applied via the element <NUM>. The film <NUM> also holds the multi-lane tow together during PNP and PBP operations, operating as a backing material.

In step 210A, PNP machine <NUM> removes the film <NUM> from the multi-lane tow <NUM>, for example, by pulling the film <NUM> off of multi-lane tow <NUM>. Because multi-lane tow <NUM> has been compacted onto preform <NUM>, the force required to remove the film <NUM> from the multi-lane tow <NUM> is less than the force required to remove the multi-lane tow <NUM> from the preform <NUM>. The film <NUM> may be removed by peeling the film <NUM> from an end or corner.

Steps 202A-210A may be repeated as desired. For example, the steps of dispensing, applying, transporting, compacting, and removing may be iteratively performed to fabricate, place, and compact multiple multi-lane tows onto a preform to increase a size (e.g., a thickness or length, or both) thickness of the preform.

Methods <NUM> and 200A provide a substantial technical benefit over prior systems, because its multi-lane tows result in less waste, increased fabrication speed, and reduced labor. Furthermore, the use of a film <NUM> helps to ensure that each multi-lane tow <NUM> is held together and is capable of resisting shear forces applied by a PBP machine <NUM>, at least because the firm bears shear forces applied by a veil, nose piece, or air bladder of the PBP machine <NUM>. Thus, even though a multi-segment tow would be expected to suffer issues relating to distorting or stretching mentioned in the background, the use of the film (and/or multiple layers) enables the multi-lane tow to bear the shear forces while complying with design requirements.

<FIG> are end views of layup and transportation of a multi-lane tow <NUM> in an illustrative embodiment. Specifically, <FIG> illustrate layup of the multi-lane tow <NUM>, and <FIG> illustrate transportation of the multi-lane tow <NUM>.

According to <FIG>, a perforated layer <NUM> of Fluorinated Ethylene Propylene (FEP) is placed atop a vacuum platen <NUM> disposed at a layup mandrel <NUM>. The vacuum platen <NUM> applies suction that holds the perforated layer <NUM> in place. The vacuum platen <NUM> may then be moved along a track to a new station.

In <FIG>, an Automated Tape Layup Machine (ATLM) head <NUM>, which is movably attached to a frame <NUM> that is indexed to the layup mandrel <NUM>, lays up a multi-lane tow <NUM> comprising one or more layers. The vacuum platen <NUM> may then proceed to a cutting station. In further embodiments, platens and/or tows may be rotated prior to pick and place (PNP) operations as desired.

In <FIG>, cutter heads <NUM>, which are movably attached to a frame <NUM> that is indexed to the layup mandrel <NUM>, cut excess material from the multi-lane tow <NUM>. In one embodiment, cutting is performed using an ultrasonic knife to enable fabrication of a pre-form to a desired engineering shape or to meet engineering requirements. In the current embodiment, the cutting is illustrated after layup of the multi-lane tow <NUM>. However, in further embodiments, this action takes place after application of a film to the multi-lane tow and prior to PNP of the multi-lane tow to the pre-form or mandrel. In <FIG>, suction heads <NUM>, which are movably attached to a frame <NUM> that is indexed to the layup mandrel <NUM>, pick up and remove the excess material (e.g., by applying greater suction than the vacuum platen <NUM>, or by applying suction to the excess material while the vacuum platen <NUM> is turned off). At this point in time, the multi-lane tow <NUM> is laid-up and cut to a desired shape, and ready for transport to a PBP machine. Thus, the vacuum platen <NUM> may proceed to a PNP station.

<FIG> illustrate transportation of the laid-up multi-lane tow. In <FIG>, a film <NUM> is applied atop the multi-lane tow <NUM>, and a PNP head <NUM>, which is movably attached to a frame <NUM> indexed to the layup mandrel <NUM>, is aligned with the multi-lane tow <NUM>. In <FIG>, the PNP head <NUM> moves downward to contact the film <NUM>. The vacuum platen <NUM> releases applied suction, and the PNP head <NUM> applies suction to the film <NUM>, rising upward as shown in <FIG> in a controlled fashion monitored by a sensor or camera <NUM>. In <FIG>, the PNP head <NUM> is positioned over a base <NUM> having a consolidation mandrel <NUM>, and the multi-lane tow <NUM> is dispensed atop the consolidation mandrel <NUM> and formed into a desired shape. The shape and length of the consolidation mandrel <NUM> varies depending on the type of part being fabricated.

The steps illustrated in <FIG> provide one embodiment of how initial layup and placement of a multi-lane tow <NUM> may be performed when fabricating a lengthwise portion of a preform such as a stringer. In a further embodiment, film <NUM> is omitted and layer <NUM> is transported with multi-lane tow to consolidate mandrel <NUM>. In this embodiment, PNP head <NUM> may receive a flipped, inverted or otherwise positioned film <NUM> and multi-lane tow <NUM> such that the multi-lane tow <NUM> is held in direct contact with the preform or surface of mandrel <NUM>.

<FIG>, <FIG>, and <FIG> are block diagrams of line fabrication environments for multi-lane tows in an illustrative embodiment. In <FIG>, a line fabrication environment <NUM> includes a track <NUM> along which a cart <NUM> loops repeatedly. The cart <NUM> proceeds from a layup station <NUM>, where it receives layup for a multi-lane tow <NUM>, to a trim and removal station <NUM>, which cuts the multi-lane tow <NUM> to desired dimensions and removes excess material. The cart <NUM> then proceeds to PNP station <NUM>, which disposes multi-lane tows in alternating fashion onto mandrels <NUM> for two neighboring forming stations. For each forming station <NUM>, a cart <NUM> proceeds along a track <NUM>. The cart <NUM> carries a mandrel <NUM>, onto which a preform <NUM> having a desired length (e.g., multiples of <NUM> meter (tens of feet)) is laid-up. The shape and length of the mandrel <NUM> varies depending on the type of part being fabricated.

The preform <NUM> consists of multiple multi-lane tows. The carts <NUM> pulse in direction <NUM> (also labeled "P") by small amounts (e.g., the width of a multi-lane tow) in order to enable the forming stations <NUM> to form the multi-lane tows <NUM> into conformance with the mandrels <NUM>. The configuration shown in <FIG> provides a technical benefit by increasing throughput in scenarios where forming stations <NUM> operate more slowly than layup station <NUM>.

In <FIG>, the line fabrication environment <NUM> includes two separate layup stations that fabricate multi-lane tows <NUM> along tracks <NUM> which are separated. A single trim and removal station <NUM> trims multi-lane tows for both of the layup stations <NUM>, and separate instances of PNP stations <NUM> provide the multi-lane tows <NUM> to two separate forming stations. The configuration shown in <FIG> provides a benefit by increasing throughput in environments where trim and removal station <NUM> operates at a faster rate than a layup station <NUM>.

In <FIG>, a layup station <NUM> is paired with two PNP stations <NUM>. In this embodiment, the multi-lane tows <NUM> are alternatingly placed on a first layer of the preform <NUM> (in region <NUM>) and onto a second layer of the preform <NUM> (in region <NUM>). Each layer is formed by a forming station <NUM>, and the multi-lane tows <NUM> in different layers may exhibit different fiber orientations. Tows in the second layer are placed atop tows in the first layer, in order to increase a thickness of the preform <NUM>. Just like in <FIG>, the configuration shown in <FIG> provides a technical benefit by increasing throughput in scenarios where forming stations <NUM> operate more slowly than layup station <NUM>.

<FIG>, <FIG>, and <FIG> illustrate but several of countless embodiments via which line assembly of preforms may be accomplished. In further embodiments, any suitable combination of tracks, stations, and machinery may be implemented to account for production criteria (e.g., the operational speed of individual stations).

<FIG> is a perspective view of a lamination system <NUM> for fabricating a multi-lane tow in an illustrative embodiment. Lamination system <NUM> may comprise an array of parallel material dispensing heads, as described in <CIT>. In this embodiment, lamination system <NUM> includes a track <NUM> upon which a shuttle <NUM> moves. A multi-lane tow <NUM> is dispensed upon/laid up at shuttle <NUM> by heads <NUM>. The angle of the heads <NUM> can be changed as desired from +<NUM>° to <NUM>° (as shown) to -<NUM>° by pivoting the heads <NUM> in unison about anchors <NUM>, (e.g., where the heads <NUM> contact the frame <NUM> to which they are attached) to a desired new orientation <NUM>. Zero-degree heads <NUM> apply lanes having a zero-degree orientation.

<FIG> further illustrates that the shuttle <NUM> has a layup surface <NUM>. During layup, each of the heads <NUM> lays up a lane <NUM> (also referred to herein as a "segment"). Each of the lanes <NUM> is therefore laid-up by a different one of the heads <NUM>.

The heads <NUM> proceed in direction <NUM> as layup continues, or may proceed in the opposite of direction <NUM>. In this manner, the heads <NUM> dispense the lanes <NUM> at an angle θ such as ninety degrees (e.g., because the heads are rotated to the same angle). In further embodiments, a subset of the heads <NUM> proceed in direction <NUM> while a different subset of the heads <NUM> proceeds in the opposite of direction <NUM>.

In embodiments where a multi-lane tow <NUM> includes multiple layers, shuttle <NUM> may move along track <NUM> in directions <NUM> in order to accurately position the layers with respect to each other. In this fashion, heads <NUM> iteratively dispense one layer after another onto the shuttle <NUM> in between movements of the shuttle <NUM>. In still further embodiments, zero-degree heads <NUM> apply one or more lanes along the horizontal direction while the shuttle <NUM> moves, in order to create a layer having a zero-degree fiber orientation. At the end of a layup movement, each of the heads <NUM> cuts a corresponding one of lanes <NUM> at the same length, in order to terminate the multi-lane tow <NUM>. Multi-lane tow <NUM> has a width (W2) and a length (L2), and each lane <NUM> has a width (W1, e.g., <NUM> (one and a half inches), or a different width that also facilitates storage on a spindle or spool) and a length (L1). In many embodiments, W2 is more than twice W1.

<FIG> is a top view of multi-lane tows fabricated for use by the PBP machine <NUM> of <FIG> in an illustrative embodiment, and corresponds with view arrows <NUM> of <FIG>. In <FIG>, a first multi-lane tow <NUM> comprises segments <NUM> dispensed at a first angle θ1 (e.g., <NUM> °), and extends for a length L1 at layup surface <NUM> of shuttle <NUM>. Excess material beyond a length L1 of the first multi-lane tow <NUM> may be trimmed to form the first multi-lane tow <NUM> into a rectangular shape if desired. <FIG> also illustrates a second multi-lane tow <NUM> that comprises segments <NUM> dispensed at a second angle θ2 (e.g., <NUM>°) and extends for a length L2.

<FIG> is a front view of a PBP machine <NUM> for compacting a multi-lane tow in an illustrative embodiment. In this embodiment, PBP machine <NUM> includes body <NUM>, and a set of spreader arms <NUM> which pivot about hinges <NUM>. A stomp foot <NUM> holds film <NUM>, which is atop the multi-lane tow <NUM> and consolidation mandrel <NUM>. Because the film <NUM> covers the multi-lane tow <NUM>, the film <NUM> resists shear loads applied by a veil <NUM>, which contacts the film <NUM>, and spreader arms <NUM> part, which forces the veil <NUM>, which is coupled on either of its ends to the spreader arms, directly against film <NUM>. The stretching of the spreader arms <NUM> places the veil <NUM> into tension and forces the veil <NUM> downward into the film <NUM>, generating compression forces and shear forces at film <NUM>. Film <NUM> bears the shear forces while transferring the compression forces to multi-lane tow <NUM>. This causes multi-lane tow <NUM> to compact without stretching. While only one set of spreader arms <NUM> and one stomp foot <NUM> are shown in <FIG>, includes additional sets of spreader arms and stomp feet that proceed into the page and carry the veil <NUM>. Further PBP machines alternatively may use a nose piece or air bladder, rather than veil <NUM>, to compress the material against the preform or mandrel by contacting the nose piece or air bladder against the multi-lane tow starting at the stomp foot and following the shape of the preform until the multi-lane tow is formed to the desired shape.

In still further embodiments, forming is performed by the systems discussed in <CIT>, entitled "APPARATUS AND METHOD FOR AUTOMATED LAYUP OF COMPOSITE STRUCTURES," and/or by the systems discussed in <CIT>, entitled "SYSTEMS AND METHODS FOR INCREMENTALLY FORMING A COMPOSITE PART.

<FIG> illustrate fabrication of a preform comprising an unhardened portion of a stringer in an illustrative embodiment. Specifically, <FIG> illustrate fabrication and consolidation of charges via the systems of <FIG>, B, or C and <FIG> provided above. However, these FIGS. may correspond with the views depicted variously in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, and are not limited to the configurations of <FIG>, B, or C.

In <FIG>, mandrel <NUM> and mandrel <NUM> are placed onto a tool <NUM>. Alternatively, mandrel <NUM> and <NUM> may be placed onto an individual tool 1510A and an individual tool 1501B. In <FIG>, a PNP machine places one or more multi-lane tows to create a first preform <NUM> and a second preform <NUM> on the mandrels. Thus, a PNP machine picks up and places laid-up material in the form of multi-lane tows which are consolidated onto mandrel <NUM> and mandrel <NUM>, respectively. In one embodiment, the multi-lane tows are made of two or more layers, and hence each applied multi-lane tow builds up a corresponding preform by at least two plies at a time. In <FIG>, a PBP machine compacts multi-lane tows to consolidate the first preform <NUM> and the second preform <NUM> against the mandrels <NUM> and <NUM>. Layup continues via the addition of additional multi-lane tows <NUM> and <NUM> as shown in <FIG>, which are compacted to form the completed preforms <NUM> and <NUM>. The mandrels <NUM> and <NUM> are then rotated in directions <NUM> and 1900A shown in <FIG>, pushing the completed preforms into contact as shown in <FIG>. Specifically, the first preform <NUM> as-completed is placed against the second preform <NUM> as-completed, and awaits placement of a gap filler at a gap between the completed preforms.

In <FIG>, a gap filler <NUM>, or "noodle," is placed onto the integral preform (e.g., via a PNP machine), and in <FIG>, a cap <NUM> covers the completed preforms and the gap filler <NUM>. The cap <NUM> can be manufactured using PNP placement and PBP forming of multi-lane tows, in a similar fashion to the completed preforms <NUM> and <NUM> discussed above. In this manner, a stringer or other structural component is rapidly constructed. Performing build-up of the preforms in the manner described herein enables the creation of preforms for stringers or other components that have complex contours which proceed into and out of the page.

<FIG> illustrate fabrication of a preform for a stringer in a further illustrative embodiment. In <FIG>, a mandrel <NUM> and a mandrel <NUM> are brought together atop a tool <NUM>. In <FIG>, a preform <NUM> is laid-up. The preform <NUM> is shaped against the mandrels by a PBP machine. In <FIG>, cutters <NUM> trim the preform <NUM> to remove excess material from the mandrels, and in <FIG> the operations of the cutters <NUM> have caused the preform <NUM> to be divided into a preform <NUM> and a preform <NUM>. In <FIG>, mandrels <NUM> and <NUM> are rotated to bring vertical portions of the preform <NUM> and the preform <NUM> into contact. A gap filler <NUM> is placed into a radial gap between the preform <NUM> and the preform <NUM> in <FIG>, and a cap <NUM> is placed atop the gap filler <NUM> to form a completed preform for a stringer in <FIG>.

<FIG> illustrate fabrication of a preform for a stringer in a further illustrative embodiment. In this embodiment, mandrel <NUM> and mandrel <NUM> of <FIG> are brought together atop base <NUM>, and in <FIG>, a preform <NUM> is laid-up atop the mandrels and shaped against the mandrels by a PBP machine. In <FIG>, cutters <NUM> remove excess material from the preform <NUM>, and divide the preform <NUM> into preform <NUM> and preform <NUM> of <FIG>. In <FIG>, the mandrel <NUM> and the mandrel <NUM> are rotated, and in <FIG> vertical portions of the preform <NUM> and <NUM> are brought together. A gap filler <NUM> is placed into a radial gap between the preform <NUM> and the preform <NUM> in <FIG>, and a cap <NUM> is placed atop the gap filler <NUM> to form a completed preform for a stringer in <FIG>.

<FIG> illustrate fabrication of a preform for a stringer in a further illustrative embodiment. In this embodiment, mandrel <NUM> and mandrel <NUM> are disposed atop a tool <NUM> as shown in <FIG>. In <FIG>, a temporary mandrel <NUM> is inserted between the mandrel <NUM> and the mandrel <NUM>, and preforms <NUM> and <NUM> are laid-up. The temporary mandrel <NUM> is removed, and, as shown in FIG. 38A, the preforms <NUM> and <NUM> are shaped against the mandrels <NUM> and <NUM>, respectively, by a PBP machine. Alternatively, as illustrated in FIG. 38A, preforms <NUM> and <NUM> (either mounted together on tool <NUM> or separately on tools 3730a and 3730b, not shown) are laid-up and shaped against the mandrels <NUM> and <NUM>, respectively, by a PBP machine, without the use of temporary mandrel <NUM>. In <FIG>, cutters <NUM> trim the preforms <NUM> and <NUM>, reducing a size of the preforms as shown in <FIG>. In <FIG>, the mandrels <NUM> and <NUM> are driven together, bringing vertical portions of the preforms <NUM> and <NUM> into contact. A gap filler <NUM> is placed into a radial gap between the preform <NUM> and the preform <NUM> in <FIG>, and a cap layer <NUM> is placed atop the gap filler <NUM> in <FIG> to form a completed preform for a stringer.

<FIG> illustrate fabrication of a preform for a stringer in a further illustrative embodiment. In <FIG>, an angular mandrel <NUM> and an angular mandrel <NUM> are disposed atop a tool <NUM>. Preforms <NUM> and <NUM> are laid-up atop the angular mandrels and shaped in <FIG> (e.g., by a PBP machine). In <FIG>, cutters <NUM> trim and remove excess material from the preforms <NUM> and <NUM>. <FIG> illustrates the preforms <NUM> and <NUM> after they have been trimmed. In <FIG>, the angular mandrels <NUM> and <NUM> are rotated and moved towards each other, until vertical portions of the preforms <NUM> and <NUM> are placed into contact. In <FIG>, a gap filler <NUM> is placed into a radial gap between the preform <NUM> and the preform <NUM>. In <FIG>, a cap <NUM> is placed atop the gap filler <NUM> to form a completed preform for a stringer.

In further embodiments, stringers of any suitable cross-section and/or size are fabricated by swapping the mandrels depicted in the FIGS. above with other mandrels having different cross-sectional shapes and/or lengths. Illustrative examples of cross-sectional shapes include portions of curved hat stringers, trapezoidal had stringers, C-channels, Z-channels, I-shaped channels, and others. For example, <FIG> illustrates mandrels <NUM> and <NUM> for fabricating a preform <NUM> in the shape of a C-channel, <FIG> illustrates mandrels <NUM> and <NUM> for fabricating a preform <NUM> for a rounded hat stringer, and <FIG> illustrates mandrels <NUM> and <NUM> for fabricating a preform <NUM> for a trapezoidal hat stringer.

<FIG> illustrates an arrangement wherein stations <NUM>, <NUM>, and <NUM> place preforms at portions <NUM>, <NUM>, and <NUM> of a wing panel preform <NUM> that are separated from inboard <NUM> to outboard <NUM>. This results in wing panel preform <NUM> having stringer preforms <NUM> assembled from stringer preform sections <NUM>-<NUM> through <NUM>-<NUM> (e.g., preforms for blade stringers or preforms for hat stringers) placed by station <NUM>, stringer preform sections <NUM>-<NUM> through <NUM>-<NUM> placed by station <NUM>, and stringer preform sections <NUM>-<NUM> through <NUM>-<NUM> placed by station <NUM>. The preforms that form different lengthwise portions of a stringer preform <NUM> may be integrated together via any suitable splicing techniques, such as scarf joints, lap splices, butt splices, or step lap splices, such as splices <NUM>-<NUM> through <NUM>-<NUM> which unite stringer preform sections <NUM>-<NUM> through <NUM>-<NUM> with stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, or splices <NUM>-<NUM> and <NUM>-<NUM>, which unite stringer preforms sections <NUM>-<NUM> and <NUM>-<NUM> with stringer preform sections <NUM>-<NUM> and <NUM>-<NUM>. This segmented approach lends itself to micro-pulsed or continuous environments fabrication environments, as each segmented set of stringer preforms <NUM> can be added at a series of stations <NUM>, <NUM>, and <NUM> as the wing panel preform <NUM> is advanced across the stations <NUM>, <NUM>, and <NUM>. In this embodiment, the wing panel preform <NUM> is advanced (e.g., pulsed or continuously moved) along a track <NUM> in a process direction <NUM>, and the stations <NUM>, <NUM>, and <NUM> apply stringer preform sections or stringer preforms during continuous motion or during pauses between pulses of the wing panel preform <NUM>. In one embodiment, the track <NUM> is configured to advance the wing panel preform <NUM> in the process direction <NUM> across the stations <NUM>, <NUM>, and <NUM>.

In one embodiment, stringer preforms or stringer preform sections are placed together (en masse) at each station. Therefore, all of various stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, <NUM>-<NUM> through <NUM>-<NUM>, and <NUM>-<NUM> through <NUM>-<NUM> may be placed at once or in groups of two or more. In order to perform this operation on the contoured surface of the wing panel preform <NUM>, blades of blade stringers (e.g., blades <NUM> of stringer preforms <NUM> of <FIG>) are arranged to be parallel to blades of adjacent blade stringers. The configurations covered in <FIG> and <FIG> allow fabrication of blade stringers (e.g., stringers <NUM> of <FIG>) where the blade (e.g., blade <NUM> of <FIG>) is parallel to an adjacent stringer even though the contour of the wing panel on which it is placed is not parallel. The parallel blade arrangement is beneficial for mass application of stringers from a fore to aft application situation. The parallel blades allow application en masse and it can be accomplished with a tooling that has reduced complexity than would otherwise be needed for mass application of non-parallel stringers. However, the parallel blade configuration may not be foregone for arrangements of <FIG> wherein one full length stringer preform is applied at a time.

<FIG> illustrates an arrangement wherein stations <NUM>, <NUM>, and <NUM> operate to place stringer preforms <NUM>, <NUM>, and <NUM> upon a wing panel preform <NUM> at portions <NUM>, <NUM>, and <NUM> of the wing panel preform <NUM> that are separated from fore <NUM> to aft <NUM>. This results in the wing panel preform <NUM> having stringer preforms <NUM>, <NUM>, and <NUM>. In one embodiment, the stringer preforms <NUM>, <NUM>, and <NUM> are assembled from stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, <NUM>-<NUM> through <NUM>-<NUM>, and <NUM>-<NUM> through <NUM>-<NUM> of <FIG> (e.g., preforms for blade stringers, preforms for hat stringers). In this embodiment, stringer preform <NUM> is placed by station <NUM>, stringer preform <NUM> is placed by station <NUM>, and stringer preform <NUM> is placed by station <NUM>. This segmented approach lends itself to pulsed or continuous fabrication environments. Furthermore, in embodiments where the stringer preforms <NUM>, <NUM>, and <NUM> are each spliced from segments, each of the stringer preform <NUM>, <NUM>, and <NUM> can be spliced together from stringer preform sections (e.g., stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, <NUM>-<NUM> through <NUM>-<NUM>, and <NUM>-<NUM> through <NUM>-<NUM> of <FIG> ) at a series of stations <NUM>, <NUM>, and <NUM> for applying stringer preforms. In this manner, a first stringer preform section <NUM>-<NUM> is spliced to a second stringer preform section <NUM>-<NUM> upon the wing panel preform <NUM>. This results in a chord-wise arrangement of first stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, and chord-wise arrangement of splices <NUM>-<NUM> through <NUM>-<NUM> between the first stringer preform sections <NUM>-<NUM> through <NUM>-<NUM> and second stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>.

In this embodiment, the wing panel preform <NUM> is advanced (e.g., pulsed or continuously moved) along a track <NUM> in a process direction <NUM>, and the stations <NUM>, <NUM>, and <NUM> apply stringer preforms <NUM>, <NUM>, and <NUM> or stringer preform segments (e.g., stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, <NUM>-<NUM> through <NUM>-<NUM>, and <NUM>-<NUM> through <NUM>-<NUM> of <FIG> ) during continuous motion or during pauses of the wing panel <NUM>. In one embodiment, the track <NUM> is configured to advance the wing panel preform <NUM> in the process direction <NUM> across the stations <NUM>, <NUM>, and <NUM>.

<FIG> illustrates an arrangement wherein station <NUM> operates to place multiple stringer preforms <NUM>, <NUM>, and <NUM> in whole (e.g., all stringer preforms are applied together, en masse via a single station) upon a wing panel preform <NUM>. The stringer preforms <NUM>, <NUM>, and <NUM> may comprise preforms for blade stringers, or preforms for hat stringers. In one embodiment, the stringer preforms <NUM>, <NUM>, and <NUM> are assembled from the stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, <NUM>-<NUM> through <NUM>-<NUM>, and <NUM>-<NUM> through <NUM>-<NUM> of <FIG>. This approach of placing all stringer preforms <NUM>, <NUM>, and <NUM> at once may be performed during a single pause between pulses, or as part of a continuous fabrication process. Furthermore, in embodiments where the stringer preforms <NUM>, <NUM>, and <NUM> are each spliced from segments, each of the stringer preforms <NUM>, <NUM>, and <NUM> can spliced together from stringer preform sections (e.g., stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, <NUM>-<NUM> through <NUM>-<NUM>, and <NUM>-<NUM> through <NUM>-<NUM> of <FIG>).

In this embodiment, the wing panel preform <NUM> is advanced (e.g., pulsed or continuously moved) along a track <NUM> in a process direction <NUM>. In a further embodiment, the track <NUM> is configured to advance the wing panel preform <NUM> in the process direction <NUM> across the stations <NUM>.

<FIG> illustrates an arrangement wherein stations <NUM>-<NUM> and <NUM>-<NUM> operates to place multiple stringer preforms <NUM>, <NUM>, <NUM>, and <NUM> in whole upon a wing panel preform <NUM>. <FIG> distinguishes from <FIG> in that multiple stringer preforms, but not all stringer preforms for a wing panel <NUM>, are placed together by a single station. Specifically, adjacent stringer preforms <NUM> and <NUM> are placed by station <NUM>-<NUM>, and adjacent stringer preforms <NUM> and <NUM> are placed by station <NUM>-<NUM>. However, in further embodiments disparate stringer preforms that are not adjacent are placed via the same station.

The stringer preforms <NUM>, <NUM>, <NUM>, and <NUM> may comprise preforms for blade stringers, or preforms for hat stringers. In one embodiment, the stringer preforms <NUM>, <NUM>, <NUM>, and <NUM> are assembled from the stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, <NUM>-<NUM> through <NUM>-<NUM>, and <NUM>-<NUM> through <NUM>-<NUM> of <FIG>. This approach of placing multiple stringer preforms <NUM> and <NUM> at once may be performed during a single pause between pulses, or as part of a continuous fabrication process. Furthermore, in embodiments where the stringer preforms <NUM>, <NUM>, <NUM>, and <NUM> are each spliced from segments, each of the stringer preforms <NUM>, <NUM>, <NUM>, and <NUM> can spliced together from stringer preform sections (e.g., stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, <NUM>-<NUM> through <NUM>-<NUM>, and <NUM>-<NUM> through <NUM>-<NUM> of <FIG> ).

<FIG> depicts a method <NUM> for picking and placing stringer preforms (e.g., stringer preforms <NUM>, <NUM>, and <NUM> of <FIG>) in an illustrative embodiment. Method <NUM> includes advancing a wing panel preform <NUM> in a process direction <NUM> in step <NUM>, applying stringer preform sections (e.g., stringer preform sections <NUM>-<NUM> through <NUM>-<NUM> of <FIG>) to a first portion <NUM> of the wing panel preform <NUM> at a first station <NUM> in step <NUM>, advancing the wing panel preform <NUM> further in the process direction <NUM> in step <NUM>, and applying stringer preform sections (e.g., stringer preform sections <NUM>-<NUM> through <NUM>-<NUM> of <FIG>) to a second portion <NUM> of the wing panel preform <NUM> at a second station <NUM> in step <NUM>. Further advancing the wing panel preform <NUM> in the process direction <NUM> and applying additional stringer preform sections to a subsequent portion of the wing panel preform <NUM> may be required (e.g., repeating steps <NUM> and <NUM>) until all stringer preform sections have been applied.

<FIG> depicts a method <NUM> for picking and placing stringer preforms (e.g., stringer preforms <NUM>, <NUM>, and <NUM> of <FIG>) in an illustrative embodiment. Method <NUM> includes advancing a wing panel preform <NUM> in a process direction <NUM> in step <NUM>. Method <NUM> further includes applying all stringer preforms (e.g., comprising stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, <NUM>-<NUM> through <NUM>-<NUM>, and <NUM>-<NUM> through <NUM>-<NUM> of <FIG>) for the wing panel preform <NUM> to the wing panel preform <NUM> via a single station <NUM>, in step <NUM>.

<FIG> depicts a method <NUM> for picking and placing stringer preforms (e.g., stringer preforms <NUM>, <NUM>, <NUM>, and <NUM> of <FIG>) in an illustrative embodiment. Method <NUM> includes advancing a wing panel preform <NUM> in a process direction <NUM> in step <NUM>, applying multiple stringer preforms <NUM> and <NUM> (e.g., comprising stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, <NUM>-<NUM> through <NUM>-<NUM>, and <NUM>-<NUM> through <NUM>-<NUM> of <FIG>) to the wing panel preform <NUM> at a first station <NUM>-<NUM> in step <NUM>, advancing the wing panel preform <NUM> further in the process direction <NUM> in step <NUM>, and applying multiple stringer preform sections <NUM> and <NUM> (e.g., comprising stringer preform sections <NUM>-<NUM> through <NUM>-<NUM>, <NUM>-<NUM> through <NUM>-<NUM>, and <NUM>-<NUM> through <NUM>-<NUM> of <FIG>) the wing panel preform <NUM> at a second station <NUM>-<NUM> in step <NUM>. Further advancing the wing panel preform <NUM> in the process direction <NUM> and applying additional stringer preform sections to a subsequent portion of the wing panel preform <NUM> may be required (e.g., repeating steps <NUM> and <NUM>) until all stringer preform sections have been applied.

<FIG> is an end illustrating placement of batches of stringer preforms at once in an illustrative embodiment, and corresponds with view arrows <NUM> of <FIG>. While eleven stringers are shown in this cross section and only three or four are shown in <FIG>, <FIG>, <FIG> and <FIG>, more stringers may be part of an actual wing panel configuration.

In <FIG>, stringer preforms <NUM> are arranged along a wing panel preform <NUM>. <FIG> therefore illustrates another possible embodiment different from <FIG> in that batches are applied by one station. Each stringer preform <NUM> includes flanges <NUM>, and the angle of flanges <NUM> may vary between different stringer preforms in order to accommodate a geometry of the wing panel preform. The flanges are complementary to the contour <NUM> of the wing panel preform <NUM> where applied, and the contour <NUM> of different stringer preforms <NUM> across the wing panel preform <NUM> is not constant. However, the angle of blades <NUM> (also referred to as "webs") of each stringer preform <NUM> are uniform between stringer preforms (e.g., vertical), and hence are parallel with each other. In one embodiment, the angle of blades <NUM> is parallel across the stringer preforms <NUM> and enhances the ease with which multiple stringer preforms <NUM> can be picked up and placed at once via a strong back <NUM>. This constant, uniform angle of blades <NUM> across the stringer preforms <NUM> enhances the ease with which multiple stringer preforms <NUM> can be picked up and placed at once via a strong back <NUM>.

The vertically aligned blades <NUM> can be quickly coupled to placement tooling in batches for quick and accurate placement. Thus, in one embodiment, a single strong <NUM> back carries a first batch <NUM> of stringer preforms <NUM> for simultaneous application to the wing panel preform <NUM>, a single strong back <NUM> carries a second batch <NUM> of stringer preforms <NUM> for simultaneous application, to the wing panel preform <NUM>, and so on along the width of the wing panel preform <NUM> from fore <NUM> to aft <NUM>. This technique provides a benefit by enhancing the speed and ease of fabrication processes pertaining to assembly of wing panel preforms <NUM>.

Attention is now directed to <FIG>, which broadly illustrates control components of a production system of a continuous fabrication line. A controller <NUM> coordinates and controls operation of laminators <NUM> and movement of one or more mobile platforms <NUM>, such as to carry the wing panel preform <NUM>, along a moving line <NUM> having a powertrain <NUM>. The controller <NUM> may comprise a processor <NUM> which is coupled with a memory <NUM> that stores programs <NUM>. In one example, the mobile platforms <NUM> are driven along a moving line <NUM> that is driven continuously by the powertrain <NUM>, which is controlled by the controller <NUM>. In this example, the mobile platform <NUM> includes utility connections <NUM> which may include electrical, pneumatic and/or hydraulic quick disconnects that couple the mobile platform <NUM> with externally sourced utilities <NUM>. In other examples, as previously mentioned, the mobile platforms <NUM> comprise Automated Guided Vehicles (AGVs) coupled to the mandrel carrying the wing panel preform that include on board utilities, as well as a GPS/Autoguidance system <NUM>. In still further examples, the movement of the mobile platforms <NUM> is controlled using laser trackers <NUM>. Position and/or motion sensors <NUM> coupled with the controller <NUM> are used to determine the position of the mobile platforms <NUM> as well as the powertrain <NUM>.

Principles of the moving line described above may include other types of operations that are normally performed in the production of composite parts. <FIG> illustrates an example of a moving line <NUM> that incorporates a variety of operations that may be required in the production of composite parts. For example, the moving line may include a station, zone, or stand for tool preparation <NUM> involving cleaning or application of coatings to a tool, following which the tool is transported on a platform to one or locations where a preform <NUM> is formed. A fully laid up preform may then be delivered on a moving line to downstream locations where debulking <NUM> and compaction <NUM> of the preform are performed. Further, the preform may be processed in additional locations where molding <NUM>, hardening <NUM> of the preform into a composite part, trimming <NUM>, inspection <NUM>, rework <NUM> and/or surface treatment <NUM> operations are performed.

<FIG> depict further methods for placing stringer preforms onto a wing panel preform <NUM> in illustrative embodiments. Specifically, <FIG> depicts a method <NUM> for placing a stringer preform upon a wing panel preform <NUM>. The method <NUM> includes creating a wing panel preform <NUM> upon a layup mandrel <NUM> in step <NUM>, and applying stringer preforms <NUM>, <NUM>, and <NUM> to the wing panel preform <NUM> in a single batch placement in step <NUM>. In one embodiment, the method further comprises placing the stringer preforms <NUM>, <NUM>, and <NUM> upon the wing panel preform <NUM> with blades <NUM> of the stringer preforms <NUM>, <NUM>, and <NUM> held parallel.

In a further embodiment, the method further includes placing the stringer preforms as stringer preform sections <NUM>-<NUM> through <NUM>-<NUM> upon the wing panel preform <NUM>. In yet another embodiment, the method includes splicing stringer preform sections <NUM>-<NUM> through <NUM>-<NUM> and <NUM>-<NUM> through <NUM>-<NUM> together upon the wing panel preform <NUM> to form the stringer preforms <NUM>, <NUM>, and <NUM>. In one embodiment, the method further comprises placing the stringer preforms <NUM>, <NUM>, and <NUM> via a Pick-and-Place (PNP) machine <NUM> upon the wing panel preform <NUM>.

<FIG> depicts a method <NUM> for placing a stringer preform upon a wing panel preform <NUM>. The method <NUM> includes creating a wing panel preform <NUM> upon a layup mandrel in step <NUM>, creating stringer preforms <NUM>, <NUM>, and <NUM> that each include a blade <NUM> in step <NUM>, and placing each of the stringer preforms <NUM>, <NUM>, and <NUM> onto the wing panel preform <NUM> while maintaining a constant, uniform angle shared between the blades <NUM> in step <NUM>.

In one embodiment, the method further comprises placing each of the stringer preforms <NUM>, <NUM>, and <NUM> with blades <NUM> of the stringer preforms <NUM>, <NUM>, and <NUM> held parallel. In another embodiment, the method further includes placing the stringer preforms <NUM>, <NUM>, and <NUM> chord-wise across the wing panel preform <NUM>. In yet another embodiment, the method further includes splicing together stringer preform sections <NUM>-<NUM> through <NUM>-<NUM> and <NUM>-<NUM> through <NUM>-<NUM> span-wise across the wing panel preform <NUM> to form the stringer preforms <NUM>, <NUM>, and <NUM>. In a further embodiment, the method further includes placing the stringer preforms <NUM>, <NUM>, and <NUM> using a plurality of stations <NUM>, <NUM>, and <NUM>. In some embodiments, the method further comprises splicing stringer perform sections <NUM>-<NUM> through <NUM>-<NUM> and <NUM>-<NUM> through <NUM>-<NUM> together upon the wing panel preform <NUM> to form the stringer preforms <NUM>, <NUM>, and <NUM>.

<FIG> depicts a method <NUM> for placing a stringer preform <NUM> upon a wing panel preform <NUM>. The method includes creating a wing panel preform <NUM> upon a layup mandrel in step <NUM>, pulsing the wing panel preform <NUM> through a series of stations in step <NUM>, and applying stringer preforms <NUM> to the wing panel preform <NUM> at each station while the wing panel preform <NUM> progresses through the stations in step <NUM>.

In further embodiments, the method comprises, placing each of the stringer preforms <NUM> with blades <NUM> of the stringer preforms <NUM> held parallel, and/or placing the stringer preforms <NUM> chord-wise across the wing panel preform <NUM>. In one embodiment, the method further comprises splicing together stringer preform sections <NUM>-<NUM> through <NUM>-<NUM> and <NUM>-<NUM> through <NUM>-<NUM> span-wise across the wing panel preform <NUM> to form the stringer preforms <NUM>. In another embodiment, the method further comprises placing multiple stringer preforms <NUM> at one time to the wing panel preform <NUM>, and/or splicing stringer perform sections together upon the wing panel preform <NUM>.

<FIG> depicts a method <NUM> for splicing stringer preforms <NUM>. The method includes creating a wing panel preform <NUM> upon a layup mandrel in step <NUM>, creating stringer preform sections in step <NUM>, placing a first stringer preform section <NUM>-<NUM> upon the wing panel preform <NUM> in step <NUM>, and splicing a second stringer section <NUM>-<NUM> to the first stringer preform section <NUM>-<NUM> in step <NUM>. In one embodiment, the method further comprises placing the second stringer preform section <NUM>-<NUM> upon the wing panel preform <NUM>.

In the following examples, additional processes, systems, and methods are described in the context of a fabrication system that creates and applies multi-lane tows for use by a PBP machine.

Referring more particularly to the drawings, embodiments of the disclosure may be described in the context of aircraft manufacturing and service in method <NUM> as shown in <FIG> and an aircraft <NUM> as shown in <FIG>. During pre-production, method <NUM> may include specification and design <NUM> of the aircraft <NUM> and material procurement <NUM>. During production, component and subassembly manufacturing <NUM> and system integration <NUM> of the aircraft <NUM> takes place. Thereafter, the aircraft <NUM> may go through certification and delivery <NUM> in order to be placed in service <NUM>. While in service by a customer, the aircraft <NUM> is scheduled for routine work in maintenance and service <NUM> (which may also include modification, reconfiguration, refurbishment, and so on). Apparatus and methods embodied herein may be employed during any one or more suitable stages of the production and service described in method <NUM> (e.g., specification and design <NUM>, material procurement <NUM>, component and subassembly manufacturing <NUM>, system integration <NUM>, certification and delivery <NUM>, service <NUM>, maintenance and service <NUM>) and/or any suitable component of aircraft <NUM> (e.g., airframe <NUM>, systems <NUM>, interior <NUM>, propulsion system <NUM>, electrical system <NUM>, hydraulic system <NUM>, environmental <NUM>).

As shown in <FIG>, the aircraft <NUM> produced by method <NUM> may include an airframe <NUM> with a plurality of systems <NUM> and an interior <NUM>. Examples of systems <NUM> include one or more of a propulsion system <NUM>, an electrical system <NUM>, a hydraulic system <NUM>, and an environmental system <NUM>. Any number of other systems may be included. Although an aerospace example is shown, the principles of the invention may be applied to other industries, such as the automotive industry.

As already mentioned above, apparatus and methods embodied herein may be employed during any one or more of the stages of the production and service described in method <NUM>. For example, components or subassemblies corresponding to component and subassembly manufacturing <NUM> may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft <NUM> is in service. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during the subassembly manufacturing <NUM> and system integration <NUM>, for example, by substantially expediting assembly of or reducing the cost of an aircraft <NUM>. Similarly, one or more of apparatus embodiments, method embodiments, or a combination thereof may be utilized while the aircraft <NUM> is in service, for example and without limitation during the maintenance and service <NUM>. For example, the techniques and systems described herein may be used for material procurement <NUM>, component and subassembly manufacturing <NUM>, system integration <NUM>, service <NUM>, and/or maintenance and service <NUM>, and/or may be used for airframe <NUM> and/or interior <NUM>. These techniques and systems may even be utilized for systems <NUM>, including, for example, propulsion system <NUM>, electrical system <NUM>, hydraulic <NUM>, and/or environmental system <NUM>.

Claim 1:
A method (<NUM>) for placing a stringer preform (<NUM>) upon a wing panel preform (<NUM>), the method comprising:
creating (<NUM>) a wing panel preform (<NUM>) upon a layup forming tool;
pulsing (<NUM>) the wing panel preform (<NUM>) through a series of stations; and
applying (<NUM>) stringer preforms (<NUM>) to the wing panel preform (<NUM>) at each station while the wing panel preform (<NUM>) progresses through the stations; and
splicing stringer perform segments together upon the wing panel preform (<NUM>).