Patent Description:
Composite parts, such as carbon fiber parts, are formed by hardening preforms of fiber reinforced material while maintaining desired amounts of pressure and temperature. A preform that has not yet been hardened into a composite part does not yet exhibit full structural strength. Thus, a "green" preform may be incapable of supporting itself as laid-up onto a surface (e.g., a vertical or other non-horizontal surface) before it is hardened. This complicates the layup of large preforms onto complex surfaces (e.g., barrel shapes), because it increases the chance of a portion of a preform peeling off or shifting off of the forming tool before layup has been completed. Hence, accurate placement or locating of large and/or unwieldy layups remains difficult.

For preforms that are hardened via vacuum bag curing techniques, it is difficult to secure a vacuum bag around the preform before the preform peels away from (or shifts relative to) a corresponding complex surface. Further complicating the issue, materials such as tacky tape, which are used to secure the vacuum bag to the tool surface, are not contact approved and hence are not allowed to touch the uncured/unhardened composite material. As a result the entire layup must be completed prior to the application of the vacuum bag and affixation of the vacuum bag (via sealant) to the complex surface. Thus, it remains desirable to quickly and effectively secure preforms (and/or other objects) to complex surfaces, particularly when preforms are being arranged into complex assemblies.

Patent document <CIT>, according to its abstract, states a laminating device comprising a pressing plate, a frame body disposed opposed to the pressing plate so as to be able to approach and depart from the pressing plate, a release sheet having elasticity and being disposed in an area between of the pressure plate and the frame body, a driving means which forms a sealed first space between the pressure plate and the release sheet by moving one of the elements defined by the pressure plate and the frame body in relation to the other of these two elements in such a way that the laminating materials arranged on the pressure plate are covered with the release sheet, pressing the release sheet against the pressure plate, thereby causing the release sheet to come into close contact with the pressure plate, a vacuum pump evacuating the first space, and a release sheet conveying means which conveys the release sheet to the area between the pressure plate and the frame body and, after laminating the laminating materials, conveys the release sheet away from the area.

Patent document <CIT>, according to its abstract, states a method for maneuvering a flexible pre-impregnated composite sheet, wherein the flexible pre-impregnated composite sheet is positioned onto a work surface and a vacuum sheet is operatively coupled to the flexible pre-impregnated composite sheet. The vacuum sheet is operatively coupled to a flexible conveyor sheet and the flexible conveyor sheet is positioned proximate to a mold such that the flexible pre-impregnated composite sheet is in contact with the mold. The vacuum sheet is decoupled from the flexible conveyor sheet and the vacuum sheet is removed from the flexible pre-impregnated composite sheet after the debulking of the flexible pre-impregnated composite sheet(s).

The disclosure provides a technique wherein a scroll of material is rapidly deployed onto a preform that has been placed onto a mandrel. The scroll includes a permeable layer that enables airflow, as well as an impermeable layer that extends beyond the boundary of the permeable layer. During and after placement of the scroll, application of negative pressure causes the scroll to press into and compact an underlying preform, via a tapeless compaction process. After compaction has been completed, the scroll can be rapidly removed to enable vacuum bagging and hardening of the preform to take place.

The disclosure also provides a method for compacting an object onto a rigid tool. The method includes placing an object onto a surface of a rigid tool, disposing an end effector over the object, spreading linkages of the end effector, causing a scroll of material between the linkages to be disposed atop the object while surrounding the object, and applying a negative pressure to the scroll that offsets air leaks between the scroll and the object, thereby forming a suction hold that compacts the object onto the rigid tool.

The disclosure also provides a non-transitory computer readable medium embodying programmed instructions which, when executed by a processor, are operable for performing a method for compacting an object onto a rigid tool. The method includes placing an object onto a surface of a rigid tool, disposing an end effector over the object, spreading linkages of the end effector, causing a scroll of material between the linkages to be disposed atop the object while surrounding the object, and applying a negative pressure to the scroll that offsets air leaks between the scroll and the object, thereby forming a suction hold that compacts the object onto the rigid tool.

The disclosure also provides an apparatus for compacting an object onto a rigid tool. The apparatus includes an end effector that is configured to move towards a rigid tool, linkages that are coupled to the end effector and are configured to pivot relative to the end effector, spindles that are coupled to the linkages and that are rotatably mounted to the linkages, and a scroll of material that is stored on the spindles, and that is configured for placement onto an object at the rigid tool.

The disclosure also provides an apparatus that includes a spindle, and a scroll of material that is wrapped around the spindle. One end of the scroll is sealed to the spindle, and another end of the scroll is affixed to an object. The material comprises a permeable layer, and an impermeable membrane that contacts the permeable layer.

The disclosure also provides an apparatus that includes at least one spindle. The spindle includes an exterior, a chamber, and perforations that couple the chamber to the exterior. The apparatus also includes a scroll of material that is wrapped around the spindle. One end of the scroll is sealed to the spindle. The material comprises a permeable layer, and an impermeable membrane that contacts the permeable layer.

The disclosure also provides an apparatus for compacting an object onto a rigid tool. The apparatus includes multiple spindles, and a scroll of material that is stored on the spindles, and that is configured for placement onto an object at the rigid tool as the spindles move apart from each other.

The disclosure also provides a method for compacting an object placed onto a surface of a rigid tool. The method includes unrolling a scroll of material, comprising an impermeable membrane that overlays a permeable layer and that extends beyond a boundary of the permeable layer, over an object, and applying a negative pressure to the permeable layer that offsets air leaks between the scroll and the object, thereby forming a suction hold that compacts the object onto the rigid tool.

The disclosure also provides a non-transitory computer readable medium embodying programmed instructions which, when executed by a processor, are operable for performing a method for compacting an object onto a rigid tool. The method includes unrolling a scroll of material, comprising an impermeable membrane that overlays a permeable layer and that extends beyond a boundary of the permeable layer, over an object, and applying a negative pressure to the permeable layer that offsets air leaks between the scroll and the object, thereby forming a suction hold that compacts the object onto the rigid tool.

The disclosure is now described, by way of example only, and with reference to the accompanying drawings.

The figures and the following description provide specific illustrative aspects 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 examples described below, but by the claims.

The scroll deployment system described herein is capable of being utilized to compact preforms for composite parts, such as a preforms for sections of fuselage. Composite parts, such as Carbon Fiber Reinforced Polymer (CFRP) parts, are initially 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 exhibit different fiber orientations in order to increase the strength of the resulting composite part along different dimensions. The preform includes 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 is infused with resin prior to hardening. For thermoset resins, the hardening is a one-way process referred to as curing, while for thermoplastic resins, the resin reaches a viscous form if it is re-heated, after which it can be consolidated to a desired shape and solidified. As used herein, the umbrella term for the process of transitioning a preform to a final hardened shape (i.e., transitioning a preform into a composite part) is referred to as "hardening," and this term encompasses both the curing of thermoset preforms and the forming/solidifying of thermoplastic preforms into a final desired shape.

<FIG> schematically illustrates a scroll deployment system <NUM>. Scroll deployment system <NUM> comprises any system or device that is capable of deploying a scroll of material over an object disposed at a rigid tool (e.g., a preform for a section of fuselage of an aircraft, disposed at a mandrel), and applying negative pressure that uniformly compacts the object onto the rigid tool. The scroll deployment system <NUM> preferably comprises an end effector <NUM> that is configured to move towards (e.g., downwards towards) a rigid tool <NUM>. Linkages <NUM> are coupled to the end effector and are configured to pivot relative to the end effector. As the linkages <NUM> pivot, their distal ends <NUM> move away from each other. Spindles <NUM> are coupled to the linkages, and are rotatably mounted to the linkages <NUM>. Furthermore, the spindles <NUM> each store a portion of a scroll <NUM> of continuous material that is configured for placement onto an object <NUM> at the rigid tool <NUM>. Thus, the spindles <NUM> carry the scroll <NUM> of material. The scroll <NUM> preferably comprises a permeable layer and an impermeable membrane, and the impermeable membrane preferably extends beyond a perimeter of the permeable layer. , The scroll <NUM> can also include one or more layers of fiber reinforced material for compacting onto the object <NUM>.

Pivoting of the linkages <NUM> causes spindles <NUM> to rotate, which deploys the scroll <NUM> of material from spindles <NUM>. After deployment, the scroll <NUM> covers the object <NUM>, and extends beyond the boundaries of the object <NUM> (e.g., circumferentially as well as into and out of the page). Accordingly, <FIG> depicts the scroll <NUM> in a deployed configuration relative to the object <NUM>. The object <NUM> is preferably a preform that comprises multiple layers of fiber reinforced material (e.g., CFRP), is disposed at a surface <NUM> of a rigid tool <NUM>, and awaits hardening into a composite part.

During and/or after deployment of the scroll <NUM>, a pump <NUM> is operated to draw air from underneath the scroll <NUM>. Specifically, the pump <NUM> draws air from underneath an impermeable membrane <NUM> (e.g., a latex sheet or other material that exhibits high levels of elongation while retaining impermeability) of the scroll <NUM> that covers the object <NUM>. Pump <NUM> draws air via a port <NUM> that penetrates into the scroll <NUM> at an aperture <NUM>, by applying negative pressure via the port <NUM>. Here the port <NUM> is located at an upper end portion <NUM> of the scroll <NUM>. However, the port <NUM> may be located as desired at other portions of the scroll as desired. Port <NUM> penetrates the impermeable membrane <NUM>, and may directly contact or be directly positioned over permeable layer <NUM> of the scroll <NUM>.

Permeable layer <NUM> is both laterally and vertically air permeable, which enables negative pressure to be distributed evenly across the scroll <NUM>. This means that negative pressure drawn via the port <NUM> is applied evenly across the object <NUM> instead of being localized at the port <NUM>. The negative pressure secures the end flaps <NUM> of the scroll to the rigid tool <NUM> and forms a loose seal between the end flaps <NUM> and the rigid tool <NUM>. That is, even though the end flaps <NUM> do not include adhesive or other means of chemical bonding, applied negative pressure loosely seals the end flaps to the rigid tool <NUM> via suction, so long as the amount of air being drawn by the pump <NUM> at least equals the amount of air lost to leaks between the end flaps <NUM> and the rigid tool <NUM>. The negative pressure also compacts the scroll <NUM> onto the object <NUM>, which ensures that the object <NUM> remains in place at the rigid tool <NUM>.

Pump <NUM> is a high flow volume pump, which means that pump <NUM> is capable of drawing a great deal of air through the port <NUM>, but not necessarily at a high pressure. The pump <NUM> preferably applies between <NUM> to <NUM> kPa (twenty-two to twenty-nine inches) of mercury in kPa (in. Hg) of negative pressure to form a vacuum, but at <NUM>'s m<NUM>/min (tens of Cubic Feet per Minute (CFM)) of airflow (e.g.,<NUM> and <NUM><NUM>/min between (fifty and two hundred CFM)). Hence, pump <NUM> and port <NUM> may be capable of maintaining a pressure of at least <NUM> kPa (one inch of mercury) across the impermeable membrane (e.g., the covered area). This may be performed solely by pump <NUM>, or in combination with other pumps as desired. The amount of pressure applied and amount of CFM drawn by pump <NUM> may vary as a function of total boundary length of the scroll <NUM>.

Controller <NUM> manages the operations of pump <NUM> based on input from a sensor (not shown) such as a pressure sensor or flow rate sensor, in order to ensure that negative pressure is constantly within a desired range to overcome leaks along the perimeter of the scroll <NUM>. Sensors may be located at any suitable location, such as at permeable layer <NUM>, scroll <NUM>, port <NUM>, pump <NUM>, etc. Controller <NUM> may increase or decrease a speed or intensity of pumping operations at pump <NUM> in order to maintain a constant volume flow of air, or in order to maintain a constant negative pressure. Controller <NUM> may be implemented, for example, as custom circuitry, as a hardware processor executing programmed instructions, or some combination thereof.

The amount of holding force (Fn) applied by the scroll <NUM> to the object <NUM> is based upon the difference between a volume per unit time drawn by pump <NUM> (VP), a volume per unit time at which air leaks through end flaps <NUM> of the scroll <NUM> (VL), and a total area covered by the scroll <NUM>. FH may also be modeled as a function of the pressure applied by pump <NUM>. VL is overcome by VP. Hence, VP should be equal to or larger than VL. Scroll <NUM> is not affixed to the rigid tool <NUM> via sealant, glue, fasteners, magnetism, etc. However, vacuum under the scroll <NUM> is maintained by pump <NUM> while air is leaking into the system through the perimeter. Thus, minor air leaks may still exist in this configuration, because negative pressure is the primary (e.g., sole) force that secures the scroll <NUM> to the rigid tool <NUM>. The air leaks may be caused by wrinkles in the scroll <NUM> that provide passages for airflow. However, wrinkles are but one cause of air leaks, as air will leak out of the edge of the scroll <NUM> when the scroll <NUM> is not sealed to the rigid tool <NUM>. Even so, VL remains small, and hence negative pressure is maintained by evacuating an equal or greater amount of air than is lost via leaks between end flaps <NUM> of impermeable membrane <NUM> and the rigid tool <NUM>.

Permeable layer <NUM> comprises a material that is capable of deforming as the impermeable membrane <NUM> applies force, drawing snugly over the object <NUM> while still enabling air to be drawn freely across the object <NUM>. That is, the permeable layer <NUM> enables the drawing of air across the object <NUM> without causing markoff at the object <NUM>. For example, the permeable layer <NUM> may comprise a compliant biplanar mesh of material that facilitates airflow. Permeable layer <NUM> is a high-flow material, which is to say that permeable layer <NUM> does not substantially restrict the rate at which pump <NUM> draws air. The resistance of permeable layer <NUM> to airflow therefore has a negligible impact on the flow rate of pump <NUM>. The permeable layer <NUM> can comprise an open celled foam material. The open celled foam material chosen is preferablt sufficiently rigid that it does not collapse under impermeable membrane <NUM>, and sufficiently open that airflow is not inhibited. Collapsing of impermeable membrane <NUM> would shut off or restrict air flow, which is undesirable as air flow would then be restricted from such areas under impermeable membrane <NUM>.

Impermeable membrane <NUM> may comprise any suitable gas-impermeable material that is pliable. For example, impermeable membrane <NUM> may comprise a plastic sheet that prevents air from escaping directly through it. Impermeable membrane <NUM> and permeable layer <NUM> may be structurally united or bonded for convenience. Both permeable layer <NUM> and impermeable membrane <NUM> can comprise contact approved materials that are acceptable for use with carbon fiber composites and do not chemically interact with resin.

Illustrative details of the operation of scroll deployment system <NUM> will be discussed with regard to an exemplary method, which is shown as method <NUM> in <FIG>. Assume, that rigid tool <NUM> awaits placement of a preform for compaction and hardening into a composite part.

<FIG> is a flowchart illustrating a method <NUM> for operating a scroll deployment system in an illustrative example. The steps of method <NUM> are described with reference to scroll deployment 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>, object <NUM> is placed onto the surface <NUM> of the rigid tool <NUM>. This preferably comprises laying up a preform onto the surface <NUM> via an Automated Fiber Placement (AFP) machine or other tool. This preferably comprises picking up and placing a preform from another location and placing it onto the surface <NUM>.

Step <NUM> comprises disposing an end effector <NUM> over the object <NUM>. This can comprise moving the end effector <NUM> over a rail, gantry, or track (not shown) in order to align the end effector with the object <NUM>.

Step <NUM> includes spreading linkages <NUM> of the end effector <NUM>, causing a scroll <NUM> of material between the linkages <NUM> to be disposed atop the object <NUM> while also surrounding the object. The linkages <NUM> can be spread by gravity as the spindles <NUM> follow a contour of the rigid tool when the end effector <NUM> is lowered. While spreading, the linkages pivot relative to the end effector <NUM>. This causes the linkages <NUM> to contact and deflect from the rigid tool <NUM> (and/or object <NUM>), swinging outward. The linkages can be motorized, and can be actively driven apart from each other. When the linkages <NUM> are spread, spindles <NUM> that are coupled with the linkages are rotated. Because the scroll <NUM> is wound about the spindles <NUM>, rotation of the spindles causes the scroll <NUM> to be dispensed, or for the material at the scroll to be unscrolled/deposited in place. This means that as the linkages <NUM> are spread, the spindles <NUM> proceed to roll in opposite directions, which exposes the scroll <NUM> for deployment. That is, because a portion of the scroll <NUM> is kept at a spindle <NUM> for one of the linkages <NUM>, and another portion of the scroll is kept at a spindle for another of the linkages, the act of spreading the linkages unrolls the scroll <NUM> from the spindles.

In step <NUM>, the scroll <NUM>, which comprises an impermeable membrane that overlays a permeable layer and extends beyond a boundary of the permeable layer, is unrolled over the object <NUM>. This can occur in response to the linkages spreading, while when linkages are not utilized, this can comprise unrolling the scroll <NUM> via any other suitable means.

In step <NUM>, the port <NUM> applies a negative pressure to the scroll <NUM> that offsets air leaks between the scroll <NUM> and the object <NUM>, thereby forming a suction hold that compacts the object <NUM> onto the rigid tool <NUM>. Applying the negative pressure draws end flaps <NUM> of the impermeable membrane <NUM> of the scroll <NUM> into contact with the rigid tool <NUM>. Applying negative pressure may be performed by drawing a desired amount of volumetric flow through the pump <NUM> as mentioned above, or by applying a constant amount of pressure via the pump <NUM>. Because air is drawn via the port <NUM>, applying negative pressure evacuates air from under the scroll <NUM>. The negative pressure applies a desired amount of force, for a desired amount of time, in order to fully compact the object <NUM>.

After compaction is completed, the linkages <NUM> are retracted, causing the scroll <NUM> to be drawn up from the preform. Where the scroll <NUM> includes one or more layers of fiber reinforced material, the compaction process can secure the fiber reinforced material to the object <NUM>. Thus, when the scroll <NUM> is retracted, these layers of fiber reinforced material remain at the object <NUM>, while the permeable layer <NUM> and the impermeable membrane <NUM> are retracted. After the scroll <NUM> is removed, the scroll <NUM> can be cleaned, re-loaded with additional layers of fiber reinforced material, and/or replaced with another spindle that is already clean and loaded with desired materials.

Method <NUM> provides a technical benefit over prior techniques, because it enables rapid deployment of a tapeless compaction system, via an end effector that occupies relatively little space. It also enables deployment of layers of fiber reinforced material as a part of the compaction process. This enhances production speed and reduces labor.

<FIG> depicts an end effector <NUM> with an undeployed scroll. The end effector <NUM> preferably includes a frame <NUM>, as well as bases <NUM>, from which linkages <NUM> extend. Actuators <NUM> are disposed at the linkages <NUM>, and facilitate retraction of the linkages <NUM> after compaction has been completed, by rolling the spindles <NUM> upward along a mandrel <NUM>. The actuators <NUM> preferably comprise motors with slip clutches that walk spindles <NUM> back upwards after compaction has been completed. Here, the end effector <NUM> deploys a scroll of material from the spindles <NUM> onto a preform <NUM> that has been placed onto the mandrel <NUM>.

<FIG> depicts the end effector <NUM> of <FIG> with a deployed scroll <NUM>. As shown in <FIG>, the spindles <NUM> have been moved to deploy the scroll <NUM> so that the scroll <NUM> covers the entirety of the preform <NUM>. A vacuum port <NUM> is utilized by a pump <NUM> to apply negative pressure during the deployment of the scroll <NUM>, and is also used after deployment to compact the preform <NUM> into place.

<FIG> is a section cut view of a scroll <NUM> and corresponds with view arrows <NUM> of <FIG>. The scroll <NUM> is wrapped around spindles <NUM>, which roll apart from each other as linkages <NUM> spread outward. This causes a web <NUM> of the scroll <NUM> to be exposed for deployment.

<FIG> is a zoomed in view of a portion of a scroll that includes layers of fiber reinforced material and corresponds with region <NUM> of <FIG>. <FIG> illustrates that the scroll <NUM> includes multiple layers. The scroll <NUM> preferably includes one or more layers <NUM> of fiber reinforced material. Layers <NUM> directly contact an underlying object when the scroll <NUM> is deployed, and may form Outer Mold Line (OML) or Inner Mold Line (IML) plies for a composite part. A permeable layer <NUM> follows the layers <NUM>, and enables negative pressure to be uniformly distributed along the underside of the scroll <NUM> when deployed, as discussed above. When the scroll <NUM> does not include layers of fiber reinforced material, the permeable layer <NUM> can be placed into direct contact with the underlying object. The permeable layer <NUM> is followed by an impermeable layer <NUM>, which prevents airflow from crossing it, when the scroll is deployed. When laid flat, the scroll <NUM> includes only one grouping <NUM> of layers <NUM>, permeable layer <NUM>, and impermeable layer <NUM>. However, the scroll <NUM> is wound around a spindle such that the grouping <NUM> is visible multiple times along the diameter of the spindle.

<FIG> depicts a permeable layer that is both vertically and laterally air-permeable. That is, air <NUM> may flow freely through gaps <NUM> in permeable layer <NUM>, as well as across gaps <NUM> in permeable layer <NUM>. This is possible because permeable layer <NUM> is a biplanar mesh. A first layer <NUM> of the biplanar mesh comprises structural elements <NUM> that are arranged parallel with each other, and a second layer <NUM> of the biplanar mesh comprises structural elements <NUM> that are arranged parallel with each other, but in a different direction than the first layer <NUM>. First layer <NUM> enables air to flow horizontally in a first direction, and second layer <NUM> enables air to flow horizontally in a second direction. Meanwhile, both layers allow air to flow freely vertically. Thus, if a negative pressure is applied to one portion of permeable layer <NUM>, the negative pressure may draw air evenly across the entirety of permeable layer <NUM>. Permeable layer <NUM> enables free airflow, and does not interfere with the drawing of air by a pump. That is, permeable layer <NUM> does not limit the CFM rate of a pump. Permeable layer <NUM> may comprise polyethylene, polypropylene, nylon, etc. Permeable layer <NUM> can be chosen as a "contact approved" material that will not chemically interfere with the adhesion of curable resin at the object being secured. For example, permeable layer <NUM> may be made from a silicone free material that does not mark an underlying object <NUM>.

The above-described apparatus and method relate to the use of an opposed pair of two rollers, and a vacuum port configured to apply vacuum via an aperture of the material. However, further configurations are possible. By way of example, the material can be scrolled on a single roller rather than an opposed pair of rollers, and/or vacuum can be applied via the end of the roller spindle, via a chamber in the spindle and perforations through the spindle. To illustrate these configurations, a vacuum system that includes both of these configurations, as well as methods for utilizing such a system, are shown in <FIG> and described next.

<FIG> is a diagram <NUM> depicting a vacuum system <NUM> coupled to a spindle <NUM>. As shown in <FIG>, the spindle <NUM> includes a chamber <NUM> having multiple perforations <NUM> that lead to an exterior <NUM>. The chamber <NUM> communicates with vacuum port <NUM>, which means that when vacuum system <NUM> evacuates air from the vacuum port <NUM>, air inside of the chamber <NUM> is removed.

A scroll <NUM> of material <NUM> is wrapped around the spindle <NUM>, and covers an underlying preform <NUM> for a composite part, or any other suitable object. An end of the scroll <NUM> is sealed to the spindle <NUM> around the perforations <NUM>, such that suction applied via vacuum port <NUM> results in negative pressure being distributed through the scroll <NUM>. Further details of this arrangement as provided in <FIG> below.

Another end <NUM> of the scroll <NUM> of material <NUM> is affixed via tape <NUM> to a surface <NUM> of the mandrel <NUM>. The end <NUM> can be affixed to the mandrel <NUM> via the application of negative pressure to the scroll <NUM>. The material <NUM> includes multiple layers, including at least one impermeable membrane <NUM>, as well as a permeable layer <NUM> (e.g., a biplanar mesh) disposed beneath the impermeable membrane <NUM>. The permeable layer <NUM> is in fluid communication with the chamber <NUM> inside of the spindle <NUM>. Further details of an arrangement of layers for the material <NUM> are discussed below with regard to <FIG>.

Implementing a spindle <NUM> that is hollow, and/or coupling a vacuum port <NUM> to the hollow portion of the spindle <NUM>, results in numerous benefits by enabling a single component (i.e., the spindle) to perform multiple functions which facilitate not just unrolling of material, but also compaction of an underlying preform <NUM>. Multiple spindles (such as the spindles depicted in <FIG>) can be implemented as hollow spindles with chambers and vacuum ports in order to apply negative pressure. Here, vacuum ports for different spindles can be placed on the same side of each of the spindles, different sides of the spindles, or both sides of the spindles as desired.

<FIG> is a cut-through view <NUM> of the spindle <NUM> of <FIG>. The dimensions of <FIG> have been adjusted to better illustrate the spindle <NUM> in relation to other components depicted in <FIG>, and hence the dimensions of these FIGS. do not correspond. <FIG> illustrates how airflow travels from the material <NUM> to the spindle <NUM> when suction is applied, as indicated by arrows. As shown in <FIG>, permeable layer <NUM> extends into contact with perforations <NUM>, and thus is in fluid communication with the perforations <NUM>. Furthermore, the perforations <NUM> are disposed between locations <NUM> where an end <NUM> of the scroll is sealed to the spindle <NUM>. The permeable layer <NUM> is bounded by a first impermeable membrane <NUM> that forms an upper boundary atop the preform <NUM>, and is further bounded by a second impermeable membrane <NUM> that forms a lower boundary. The impermeable membranes contact the permeable layer, and hence contain airflow to within the permeable layer <NUM>.

The first impermeable membrane <NUM> terminates after the permeable layer <NUM>, and the second impermeable membrane <NUM> terminates prior to reaching the preform <NUM>. The second impermeable membrane <NUM> prevents pressure loss from the permeable layer <NUM> during and after the unrolling process, by providing a direct flow pathway to the chamber <NUM> of the spindle <NUM>. As discussed above, the scroll <NUM> can be wrapped around a second spindle, and end <NUM> of the scroll is sealed to the second spindle in a similar fashion to that described above for end <NUM>.

<FIG> is a flowchart depicting a method <NUM> of applying negative pressure via a spindle. Step <NUM> includes disposing a spindle <NUM> atop an object, such as a preform for a composite part. This may comprise physically placing the spindle <NUM> onto the object, or onto a mandrel <NUM> that the object has been laid-up onto. Step <NUM> includes unrolling a scroll <NUM> of material <NUM> from the spindle <NUM> over the object, thereby covering the object with the material. The act of unrolling preferably places the permeable layer directly into contact with the object.

Step <NUM> includes applying negative pressure to a permeable layer <NUM> in the material <NUM> that is in fluid communication with a chamber <NUM> inside of the spindle <NUM>. Applying the negative pressure can be performed via a vacuum port <NUM> in fluid communication with the chamber <NUM>, and via multiple perforations <NUM> at the spindle <NUM> that link the chamber <NUM> to the permeable layer <NUM>. The negative pressure is distributed across the impermeable membrane via the permeable layer, which ensures that the impermeable membrane does not "pinch off' or self-seal in response to negative pressure at an undesired location. Step <NUM> includes forming a suction hold that draws an impermeable membrane of the material into contact with the object, in response to the negative pressure. The suction hold is formed naturally as negative pressure is distributed across the impermeable membrane. At locations where the permeable layer <NUM> terminates and the impermeable membrane <NUM> continues, the negative pressure causes the impermeable membrane to seal itself to the underlying mandrel <NUM>.

<FIG> is a flowchart depicting a method <NUM> of unrolling a scroll from a single spindle. Method <NUM> includes disposing a spindle <NUM> atop an object located at a mandrel <NUM> in step <NUM>. Step <NUM> includes affixing an end <NUM> of a scroll <NUM> of material at the spindle <NUM> to the mandrel <NUM>. Affixing the end <NUM> of the scroll may comprise taping the end <NUM> of the scroll <NUM> to the mandrel <NUM>. Affixing the end of the scroll may comprise forming a suction hold between an impermeable membrane of the material and the mandrel, as discussed above for method <NUM>. Thus, activating a vacuum system <NUM> can serve to affix the end <NUM>, as long as no substantial air leaks exist.

Step <NUM> includes applying negative pressure to a permeable layer in the material, thereby forming a suction hold that places the material into contact with the object. This can be performed in a similar manner to step <NUM> of method <NUM> discussed above. Applying the negative pressure can be performed via multiple perforations <NUM> at the spindle that link a chamber of the spindle to the permeable layer. The permeable layer <NUM> distributes the negative pressure across the impermeable membranes of the material.

Step <NUM> includes unrolling the scroll while the negative pressure is applied. Unrolling the scroll preferably comprises covering a preform for a composite part. Unrolling the scroll places the permeable layer directly into contact with the object. Furthermore, because the end <NUM> of the scroll <NUM> is affixed in place, the scroll does not wander or change position as the unrolling process continues. This enables the entire scroll to be unwound (or the entire object to be covered) as desired. The method preferably further comprises compacting the object via the suction hold. This can comprise increasing negative pressure until the object is pressed firmly into the mandrel at a desired level of pressure.

While <FIG> depict a single roller, tube-applied vacuum apparatus and related methods, various aspects and features mentioned herein can be applied to a variety of systems. For example, the arrangement of chambers and vacuum systems depicted in these <FIG> may be applied to a two-roller example as depicted in in <FIG> and <FIG> except with the vacuum applied via one or more ends of one or both spindles. A one-roller example as depicted in these <FIG> may apply vacuum via an aperture in the material as discussed with regard to <FIG> and <FIG>.

In the following examples, additional processes, systems, and methods are described in the context of a scroll deployment system for compacting preforms onto rigid tooling (e.g., a mandrel).

Referring more particularly to the drawings, 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 examples, method examples, 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 examples, method examples, 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>.

A part preferably comprises a portion of airframe <NUM>, and is manufactured during component and subassembly manufacturing <NUM>.

Claim 1:
A method for compacting an object (<NUM>) placed onto a surface of a rigid tool (<NUM>), the method comprising:
unrolling (<NUM>) a scroll (<NUM>) of material, comprising an impermeable membrane (<NUM>) that overlays a permeable layer (<NUM>) and that extends beyond a boundary of the permeable layer (<NUM>), over an object (<NUM>); and
applying (<NUM>) a negative pressure to the permeable layer (<NUM>) that offsets air leaks between the scroll (<NUM>) and the object (<NUM>), thereby forming a suction hold that compacts the object (<NUM>) onto the rigid tool (<NUM>).