Patent ID: 12208453

DETAILED DESCRIPTION

The illustrative embodiments recognize and take into account one or more different considerations. The illustrative embodiments recognize and take into account that prior to machining the sheet, the sheet is restrained against a backing plate style support tool. Often, the sheet is restrained at the periphery, leaving the remainder of the sheet unrestrained such that the restraint does not inhibit processing. While the periphery of sheet is restrained, the remainder of the sheet may bend such that portions of the sheet are not in contact with the support surface of the support tool. The portions of the sheet not in contact with the support surface are unsupported. While the periphery of the sheet is restrained against the support tool, a machining operation is performed on a portion of the sheet. The portion of the sheet to be machined may not be contacting the support tool and may be unsupported.

The illustrative embodiments recognize and take into account that performing machining operations on an unsupported portion of the sheet results in spring back. For example, when using a conventional drill system to drill holes, the drill bit initially makes contact with the unsupported surface of the sheet and applies pressure to the sheet. The pressure, or machining force, applied from the drill bit initially causes the sheet to compress against the support tool prior to penetrating through the sheet. Once the sheet is completely penetrated, the elastic energy causes the sheet to rapidly spring back to its free state. This spring back of the sheet is uncontrolled.

The sheet is pushed by the machining force of the drill bit in the direction of the support tool during the machining operation. After the drill bit passes through the sheet, the sheet is no longer subjected to the pushing machining force of the drill bit, and the sheet springs back to its original location.

The illustrative embodiments recognize and take into account that a support tool desirably mirrors the shape of the sheet. The illustrative embodiments recognize and take into account that a support tool may not precisely mirror the shape of the sheet over the entirety of the support tool. The illustrative embodiments recognize and take into account that the support surface of the support tool may be non-planar to support the sheet. The illustrative embodiments recognize and take into account that restraining a sheet on a support tool may result in a gap between the support surface and the sheet.

The illustrative embodiments recognize and take into account that in some examples the support surface of the support tool may be non-planar to support the sheet. In some illustrative examples, the non-planar support tool surface may be concave. When the support surface is non-planar, restraining the periphery of sheet causes the remainder of the sheet to bend such that portions of the sheet are not in contact with the support surface of the support tool. The illustrative embodiments recognize and take into account that a combination of the shape of the sheet and the shape of the support tool may cause gaps between the sheet and the support tool. The illustrative embodiments recognize and take into account that a gap may occur even when potential spring back energy is present in the sheet.

The illustrative embodiments recognize and take into account that performing machining operations on an unsupported portion of the sheet may result in undesirable locations for the machining operations. The illustrative embodiments recognize and take into account that it may be desirable for the sheet to contact the support surface for desirable positioning of features created during the machining operations.

The illustrative embodiments also recognize and take into account that to reduce spring back following a machining operation, a sheet of material may be tacked to a support tool using a temporary adhesive. However, adhesive residue may transfer to machining tools, such as drill bits. Adhesive residue on machining tools may undesirably affect at least one of the life of the machining tools, or the quality of the manufactured component. For example, adhesive residue may undesirably affect the quality of drilled holes in a manufactured component. The illustrative embodiments recognize and take into account that applying an adhesive adds time and cost to the manufacturing process.

Additionally, an adhesive used to hold a sheet of material to a support tool would be qualified for contact use with the type of material of the sheet as well as the material of the support tool. It would be undesirable to use an adhesive that would damage either the material of the sheet or the material of the support tool. Depending upon the material of the sheet, there may be a limited quantity of qualified adhesives.

In some manufacturing operations, vacuum is applied to a sheet to hold the sheet against a support tool. However, conventional vacuum plates having vacuum channels around the periphery do not apply vacuum to the center of the sheet where machining operations are performed. Machining operations, such as perforating processes, would diminish the effectiveness of conventional vacuum plates with vacuum channels in the region of machining operations.

The illustrative embodiments recognize and take into account that conventional methods of attempting to reduce spring back include methods of holding the sheet against the support tool. Conventional methods of attempting to reduce spring back include methods of increasing the supported surface of the sheet around the periphery of the sheet.

The illustrative embodiments recognize and take into account that uncontrolled spring back occurs when a sheet is placed into tension by a machining force and the tension is uncontrollably released after a machining tool passes through the sheet and the machining force is no longer applied to the sheet. The illustrative embodiments recognize and take into account that if the release of tension in the sheet were to be controlled, the spring back would be controlled.

The illustrative embodiments provide machining systems and methods for reducing spring back in machining operations. The illustrative embodiments apply a compression force to the surface of the sheet as the machining operation is performed on the surface of the sheet. By applying the compression force, spring back of the sheet following the machining operation is reduced or eliminated. In some illustrative embodiments, a number of biasing devices apply a load to the sheet to deflect the sheet prior to a machining operation such that spring back following the machining operation is reduced to within desirable limits. After removing the compression force, the sheet experiences a controlled spring back to its original shape. At least one of the rate of spring back or the initiation of spring back relative to the machining operation is controlled.

Turning now toFIG.1, an illustration of a block diagram of a manufacturing environment in which a machining system configured to reduce spring back following a machining operation is utilized is depicted in accordance with an illustrative embodiment. Machining system100in manufacturing environment102is configured to reduce spring back following a machining operation.

Machining system100comprises machining tool104and spring back control system106. Spring back control system106comprises number of force generators108and number of force loaded members110coupled to number of force generators108. Each force loaded member of number of force loaded members110comprises a material contact surface. For example, force loaded member111comprises material contact surface113.

As used herein, a “number of” items means one or more items. For example, a number of force loaded members means one or more force loaded members.

Material contact surface113is formed of any desirable material. Material contact surface113is configured to not undesirably affect surface122of sheet120. In one example, the shape of material contact surface113is selected to not undesirably mar, bend, or mark surface122of sheet120. As another example, the material of material contact surface113is selected to not undesirably mar, bend, or mark surface122of sheet120. In another illustrative example, the material of material contact surface113is selected to slip relative to surface122. In another illustrative example, the material of material contact surface113is selected to grip and maintain the position of material contact surface113relative to surface122.

Machining tool104comprises any desirable type of tool. In some illustrative examples, machining tool104comprises a cutting tool. In one illustrative example, machining tool104comprises drill bit112. In other illustrative examples, machining tool104may be selected from a blade, a punch, a mill, or any other desirable cutting tool. In other illustrative examples, machining tool104may be selected from a joining tool, a welding tool, or any other desirable type of tool.

In some illustrative examples, machining tool104is independently moveable relative to spring back control system106. In some illustrative examples, machining tool104is independently moveable relative to number of force generators108. In one illustrative example, machining tool104is independently moveable relative to spring back control system106in first direction114. First direction114is parallel to application of compression force116. Compression force116applied by spring back control system106to sheet120is parallel to first direction114and application of force to sheet120by machining tool104. In another illustrative examples, machining tool104is independently moveable relative to spring back control system106in second direction118perpendicular to first direction114.

When machining tool104is independently moveable relative to spring back control system106, machining tool104may be used to perform machining operations such as slotting or countersinking that may involve movement of machining tool104in second direction118. When machining tool104is independently moveable relative to spring back control system106, machining tool104may be used to perform multiple machining operation instances without moving spring back control system106relative to sheet120.

Spring back control system106provides compression force116against sheet120. Spring back control system106provides compression force116to surface122of sheet120to form region124of applied compressive force. Machining operations, such as machining operation126, are performed in region124. Machining operations take any desirable form including drilling, milling, countersinking, or any other desirable machining operation.

Sheet120is formed of material128. Material128takes the form of any desirable material that has elastic deformation130. During machining operation126, force applied by machining tool104placing sheet120in tension until machining tool104penetrates sheet120. In some illustrative examples, material128is one of metal132or composite material134. When material128is composite material134, composite material134is cured or partially cured.

In some illustrative examples, sheet120is referred to as thin sheet136. Sheet120may be referred to as thin sheet136, as sheet120is thin enough to deflect when machining force of machining operation126is applied to sheet120without compression force116applied.

Sheet120is restrained against support tool138. In some illustrative examples, when sheet120is restrained against support tool138, gap140is present between portions of sheet120and support surface142of support tool138. In some illustrative examples, gap140is present due to concave curvature144of support surface142. Gap140is not present behind the entirety of sheet120, but is present behind at least some of the locations where machining operation126will be performed.

If machining operation126were performed on surface122without compression force116from spring back control system106, spring back146following machining operation126may have an undesirable force. If machining operation126were performed on surface122without compression force116from spring back control system106, spring back146is uncontrolled. By applying compression force116to surface122as machining operation126is performed, spring back146following machining operation126is reduced. Spring back control system106reduces spring back146following machining operation126to at or below a desired threshold. Specifically, spring back146from machining operation126when compression force116is applied is less than the spring back experienced when compression force116is not applied during machining operation126. In some illustrative examples, spring back146following machining operation126is eliminated when compression force116is applied during machining operation126.

Compression force116applied to surface122is sufficient to desirably reduce spring back146of sheet120following machining operation126. Compression force116is not high enough to cause permanent deformation to sheet120. In some illustrative examples, compression force116is configured to be sufficient to cause sheet120to contact support surface142of support tool138in region124of compressive force. Number of force generators108are selected to apply a desired amount of compression force116. In some illustrative examples, number of force generators108are removable and interchangeable so that force generators of a desired strength can be introduced to spring back control system106.

In some illustrative examples, when compression force116is applied to surface122of sheet120, sheet120deflects towards support surface142of support tool138. When sheet120deflects towards support surface142, gap140is reduced. By maintaining compression force116following machining operation126, sheet120returns to its original shape in a controlled fashion.

When compression force116deflects sheet120towards support surface142, a machining force of machining operation126deflects sheet120towards support surface142less than the deflection by compression force116. Machining operation126is performed on sheet120while compression force116is applied to sheet120. After machining tool104extends through sheet120, the machining force is no longer applied to sheet120and any deflection of sheet120from machining operation126results in spring back146. Spring back146is less when compression force116is applied. Compression force116is removed after machining operation126is complete. When compression force116is removed, sheet120returns to its shape due to elastic deformation130.

When compression force116is removed, spring back147of sheet120occurs as sheet120returns to its original shape. Spring back147may also be referred to as a “controlled spring back.” At least one of the rate of spring back147or the initiation of spring back147relative to machining operation126is controlled. In some illustrative examples, spring back147occurs locally as compression force116is removed locally, but compression force116is maintained against sheet120as compression force116moves across sheet120. In some illustrative examples, spring back147occurs for all of sheet120as compression force116is removed from sheet120.

Spring back control system106applies compression force116. Number of force generators108of spring back control system106provide force to number of force loaded members110coupled to number of force generators108. Number of force generators108takes any desirable form. In some illustrative examples, number of force generators108is number of linear force generators148. Number of linear force generators148is a number of force generators configured to apply a force in a linear direction. Number of linear force generators148need not be linear in shape. In some illustrative examples, number of linear force generators148comprises at least one of a number of springs or a number of pneumatic cylinders. In some illustrative examples, number of force generators108is referred to as number of biasing devices149. Number of biasing devices149provides compression force116applied to sheet120to reduce spring back146occurring from machining operation126. By applying compression force116, tension on sheet120introduced by machining operation126is reduced. By applying compression force116, sheet120moves towards support tool138. In some illustrative examples, compression force116is maintained on sheet120as multiple instances of machining operation126are performed on sheet120. In some illustrative examples, compression force116is removed from sheet120after each instance of machining operation126.

Each force loaded member of number of force loaded members110is associated with a respective force generator of number of force generators108. In some illustrative examples, multiple force generators of number of force generators108are coupled to a single force loaded member of number of force loaded members110. In some illustrative examples, each force generator of number of force generators108is coupled to a single respective force loaded member of number of force loaded members110.

Number of force loaded members110comprises at least one of a number of rollers or a number of pads. Each force loaded member of number of force loaded members110comprises a respective material contact surface, material contact surface113. Each material contact surface113is one of roller150or pad152.

In some illustrative examples, when material contact surface113is roller150, roller150may remain in contact with surface122of sheet120as machining system100moves in second direction118. In some illustrative examples, when material contact surface113is roller150, roller150may remain in contact with surface122of sheet120as machining operation126is performed at multiple locations of sheet120.

In some illustrative examples, when material contact surface113is pad152, pad152is removed from surface122of sheet120prior to movement of machining system100in second direction118. In some illustrative examples, when material contact surface113is pad152, machining tool104moves relative to pad152while machining tool104performs machining operation126. In some illustrative examples, machining tool104moves in second direction118relative to pad152while machining tool104performs countersinking, routing, slotting, or any other desirable machining operation.

In some illustrative examples, number of force loaded members110and machining tool104move in first direction114towards surface122simultaneously to perform machining operation126. In some illustrative examples, machining tool104moves in first direction114to perform machining operation126after number of force loaded members110contact surface122and apply compression force116.

In some illustrative examples, number of force loaded members110includes a plurality of force loaded members. In some of these illustrative examples, number of force loaded members110comprises a plurality of pads configured to apply compression force116to surface122of sheet120to form region124of applied compressive force. In these illustrative examples, region124is substantially between number of force loaded members110. In these illustrative examples, number of force loaded members110are removed from surface122prior to moving machining system100in second direction118. In these illustrative examples, number of force loaded members110are removed from contact with sheet120after dampening spring back146from machining operation126.

In some illustrative examples, number of force loaded members110includes a single force loaded member. In some of these illustrative examples, number of force loaded members110comprises a single pad, pad152. In these illustrative examples, number of force loaded members110comprises pad152configured to form working envelope153for machining tool104. When number of force loaded members110comprises pad152with working envelope153, machining tool104performs machining operation126through working envelope153. In one illustrative example, machining tool104is drill bit112, and drill bit112extends through working envelope153to perform machining operation126on sheet120. In some illustrative examples, machining tool104may perform machining operation126in multiple locations on sheet120without moving pad152.

In some illustrative examples, each of number of force loaded members110further comprises linear bearing154and carriage156. In some illustrative examples, when present, linear bearing154and carriage156restricts movement of number of force loaded members110to first direction114. In some illustrative examples, when present, linear bearing154and carriage156restricts movement of number of force loaded members110in second direction118. When present, linear bearing154and carriage156restrict application of compression force116to first direction114.

In some illustrative examples, machining system100comprises number of linear force generators148, number of force loaded members110coupled to number of linear force generators148and configured to apply compression force116to form region124of applied compressive force, and machining tool104independently moveable relative to number of linear force generators148in first direction114parallel to number of linear force generators148. Machining tool104is positioned to perform machining operation126within region124.

In some illustrative examples, number of force loaded members110is each equidistant from machining tool104. In one illustrative example, number of force loaded members110may be three force loaded members arranged in a triangle. In this illustrative example, machining tool104may be centered within the triangle formed by number of force loaded members110. In another illustrative example, number of force loaded members110may be two force loaded members. In this illustrative example, machining tool104may be positioned between force loaded members110. In yet another illustrative example, number of force loaded members110may be four force loaded members positioned in a rectangular or square pattern. In this illustrative example, machining tool104is centered within the rectangle or square formed by the four force loaded members.

In some illustrative examples, number of force loaded members110comprises pad152configured to form working envelope153for machining tool104. In these illustrative examples, pad152may also be referred to as a “foot”. In these illustrative examples, pad152may be connected to multiple force generators of number of force generators108.

In some illustrative examples, machining tool104is independently moveable in second direction118perpendicular to number of linear force generators148. When machining tool104is independently moveable in second direction118, machining tool104is independently moveable along surface122of sheet120. In some illustrative examples, machining tool104is moved in second direction118while number of force loaded members110contact surface122and apply compression force116. In these illustrative examples, machining tool104may be used to form a slot, a channel, a hole larger than the machining tool104, or any other desirable feature. In some illustrative examples, machining tool104comprises drill bit112having axis158parallel to number of linear force generators148. In some illustrative examples, machining tool104comprises drill bit112having axis158parallel to first direction114.

In some illustrative examples, machining system100takes the form of end effector160. In some illustrative examples, end effector160is connected to any desirable robotic device, such as a robotic arm.

Machining system100performs machining operation126on sheet120to form component162. Component162is a component of any desirable platform. The platform may be, for example, a vehicle, a mobile platform, a stationary platform, a land-based structure, an aquatic-based structure, or a space-based structure. More specifically, a platform may be a surface ship, a tank, a personnel carrier, a train, a spacecraft, a space station, a satellite, a submarine, an automobile, a power plant, a bridge, a dam, a house, a manufacturing facility, a building, or other suitable platforms. In some illustrative examples, the platform takes the form of an aircraft. In these illustrative examples, component162is aircraft component164.

Component162has at least one feature formed by machining tool104in machining operation126. For example, component162may have a plurality of slots, a plurality of channels, a plurality of holes, or any other desired feature. In some illustrative examples, component162is a perforated component. In some illustrative examples, component162takes the form of dampener166. Dampener166may be an acoustic dampener, a pressure dampener, or any other type of dampener. In some illustrative examples, component162is a face sheet of a sandwich panel structure. The illustration of manufacturing environment102and machining system100inFIG.1is not meant to imply physical or architectural limitations to the manner in which an illustrative embodiment may be implemented. Other components in addition to or in place of the ones illustrated may be used. Some components may be unnecessary. Also, the blocks are presented to illustrate some functional components. One or more of these blocks may be combined, divided, or combined and divided into different blocks when implemented in an illustrative embodiment.

For example, although only force loaded member111is depicted within number of force loaded members110, number of force loaded members110has any desirable quantity of force loaded members. For example, number of force loaded members110may include two, three, four, or more than four force loaded members. Each force loaded member of number of force loaded members110comprises a pad or a roller.

As another example, other non-depicted components or systems of machining system100may be present in machining system100. For example, a debris removal system may be present to remove any debris generated by machining operation126. As another example, utility connections and other components may be present to support machining system100. As yet another example, material128may be another type of material having elastic deformation130, such as a polymeric material.

Although not depicted, in some illustrative examples, spring back control system106may further comprise force adjusters configured to adjust an amount of compression force116applied. The force adjusters could be manual or automated.

Additionally, although only end effector160is depicted, in some illustrative examples, machining system100includes more than one end effector. In some illustrative examples, spring back control system106is part of a first end effector while machining tool104is a component of a second end effector.

Turning now toFIG.2, an illustration of a perspective view of a machining system configured to reduce spring back following a machining operation is depicted in accordance with an illustrative embodiment. Machining system200is a physical implementation of machining system100ofFIG.1. Machining system200is configured to reduce spring back following a machining operation. Machining system200reduces spring back from a machining operation by applying a compression force to a sheet until the machining operation is completed. When the machining force of the machining operation is removed, spring back following the machining operation is at or below a desired threshold. Controlled spring back of the sheet occurs when the compression force is removed from the sheet.

Machining system200comprises number of linear force generators202, number of force loaded members204coupled to number of linear force generators202, and machining tool206independently moveable relative to number of linear force generators202in first direction208parallel to number of linear force generators202. Number of force loaded members204is configured to apply compression force to form a region of applied compressive force. Machining tool206is positioned to perform a machining operation within the region.

As depicted, number of force loaded members204is each equidistant from machining tool206. As depicted, number of force loaded members204comprises pad210configured to form working envelope212for machining tool206. Number of linear force generators202takes any desirable form. In some illustrative examples, number of linear force generators202comprises at least one of a number of springs or a number of pneumatic cylinders.

Machining tool206is independently moveable in second direction214perpendicular to number of linear force generators202. As depicted, machining tool206comprises drill bit216having axis218parallel to number of linear force generators202.

As depicted, machining system200takes the form of end effector220. End effector220is configured to reduce spring back following a machining operation.

Machining system200comprises machining tool206and spring back control system222. Spring back control system222comprises number of force generators224and number of force loaded members204coupled to number of force generators224. Each force loaded member of number of force loaded members204comprises a material contact surface. As depicted, pad210of number of force loaded members204has material contact surface226.

In end effector220, multiple force generators of number of force generators224are coupled to a single force loaded member of number of force loaded members204. In end effector220, each of number of force generators224is coupled to a single force loaded member comprising pad210.

Turning now toFIG.3, an illustration of a bottom view of a machining system configured to reduce spring back following a machining operation is depicted in accordance with an illustrative embodiment. In view300, working envelope212of pad210is visible. As can be seen in view300, machining tool206will move in first direction208ofFIG.2to extend through working envelope212to perform a machining operation on a workpiece. In view300, first direction208ofFIG.2moves into and out of the page.

To reduce spring back following a machining operation using machining tool206, pad210is placed in contact with the surface of a workpiece. A compression force is applied to the workpiece using number of force generators224to form a region of applied compressive force. A machining operation will be performed in the region using machining tool206while the compression force is applied to the sheet.

Turning now toFIG.4, an illustration of a side view of a machining system configured to reduce spring back following a machining operation is depicted in accordance with an illustrative embodiment. Machining system400is a physical implementation of machining system100ofFIG.1. Machining system400is a second non-limiting example of machining system100ofFIG.1. Machining system400is configured to reduce spring back following a machining operation.

Machining system400comprises machining tool402and spring back control system404. Spring back control system404comprises number of force generators406and number of force loaded members408coupled to number of force generators406. Each force loaded member of number of force loaded members408comprises a material contact surface.

For example, force loaded member410of number of force loaded members408comprises material contact surface412. Each material contact surface is one of a roller or a pad. Material contact surface412takes the form of roller414.

As depicted, each of number of force loaded members408of machining system400comprises a linear bearing and a carriage. For example, force loaded member410comprises linear bearing416and carriage418. Linear bearing416and carriage418restrict movement of force loaded member410to first direction420.

Machining system400comprises number of linear force generators422, number of force loaded members408coupled to number of linear force generators422and configured to apply a compression force to form a region of applied compressive force, and machining tool402independently moveable relative to the number of linear force generators422in first direction420parallel to the number of linear force generators, machining tool402is positioned to perform a machining operation within the region. In some illustrative examples, machining tool402is independently moveable in a second direction perpendicular to number of linear force generators422.

Turning now toFIG.5, an illustration of a front view of a machining system configured to reduce spring back following a machining operation is depicted in accordance with an illustrative embodiment. View500is a front view of machining system400ofFIG.4.

In view500, force loaded member502is visible. Force loaded member502of number of force loaded members408comprises material contact surface504. Material contact surface504takes the form of roller506.

In this illustrative example, each force loaded member of number of force loaded members408is associated with a respective force generator of number of force generators406. For example, force generator508is associated with force loaded member410and force generator510is associated with force loaded member502.

Each of force generator508and force generator510provides a desirable amount of force to control spring back of a sheet of material following a machining operation. Each of force generator508and force generator510may be selected based on a desired amount of force. As depicted, number of force generators406further comprises force adjuster518and force adjuster520. As depicted, force adjuster518and force adjuster520may be loosened or tightened to adjust the pre-load for number of force generators406.

As depicted, machining tool402comprises drill bit512. As depicted, drill bit512has axis514. As depicted, number of force generators406takes the form of number of linear force generators422. As depicted, axis514is parallel to number of linear force generators422. As depicted, machining tool402is positioned between roller414and roller506. As depicted, number of force loaded members408is each equidistant from machining tool402. In some illustrative examples, number of force loaded members408is not equidistant from machining tool402.

As depicted, machining tool402comprises drill bit512having an axis514parallel to number of linear force generators422. In some illustrative examples, machining tool402is independently moveable relative to spring back control system404.

As depicted, number of linear force generators422comprises at least one of a number of springs or a number of pneumatic cylinders. As depicted, number of linear force generators422comprises number of springs516.

Turning now toFIG.6, an illustration of a front view of a machining system above a sheet is depicted in accordance with an illustrative embodiment. Machining system600is a physical implementation of machining system100ofFIG.1. Machining system600may be the same as machining system400ofFIGS.4-5.

In view602, machining system600is positioned above workpiece604in manufacturing environment605. Workpiece604takes the form of sheet606. Sheet606is associated with support tool608. Sheet606is associated with support tool608by being restrained relative to support tool608. Sheet606is restrained relative to support tool608by securing the periphery (not depicted) of sheet606relative to support tool608. View602is of a portion of sheet606that will receive a machining operation.

The periphery of sheet606will not receive a machining operation. The description of securing periphery is only illustrative, any desirable amount of sheet606is restrained against support tool608. Portion610of sheet606is not in contact with support tool608. Portion610of sheet606is unsupported.

Machining system600takes the form of end effector612. End effector612is configured to reduce spring back following a machining operation. Machining system600comprises machining tool614and spring back control system616. Spring back control system616comprises number of force generators618and number of force loaded members620coupled to number of force generators618. Each force loaded member of number of force loaded members620comprises a material contact surface. As depicted, each material contact surface is a roller. For example, force loaded member624comprises roller625. As another example, force loaded member628comprises roller627.

As depicted, machining tool614comprises drill bit622. Each force loaded member of number of force loaded members620is associated with a respective force generator of number of force generators618. For example, force loaded member624of number of force loaded members620is associated with force generator626of number of force generators618. As another example, force loaded member628of number of force loaded members620is associated with force generator630of number of force generators618.

Prior to performing a machining operation on sheet606using drill bit622, a compression force will be applied to sheet606by spring back control system616. A compression force applied by spring back control system616will reduce the spring back of sheet606caused by a machining operation on sheet606. The compression force is applied in anticipation of a spring back of sheet606.

Turning now toFIG.7, an illustration of a front view of force loaded members of a machining system in contact with a sheet is depicted in accordance with an illustrative embodiment. In view700, roller625and roller627are in contact with surface702of sheet606. Machining tool614is not in contact with surface702. In view700, gap704is present between sheet606and support tool608.

In view700, a compression force is not yet allowed to surface702. In view700, roller625and roller627are in contact with surface702but do not yet apply a force to sheet606.

Turning now toFIG.8, an illustration of a front view of force loaded members of a machining system applying a compression force to a sheet is depicted in accordance with an illustrative embodiment. In view800, compression force802is applied to sheet606using number of force generators618coupled to number of force loaded members620to form region803of applied compressive force.

In view800, compression force802deflects sheet606towards support tool608. By deflecting sheet606towards support tool608, sheet606is placed into tension. By deflecting sheet606towards support tool608, gap704between sheet606and support tool608is reduced between view700ofFIG.7and view800. In view800, no visible gap is present between sheet606and support tool608. However, view800is not meant to imply physical or architectural limitations to the manner in which an illustrative embodiment may be implemented. In other illustrative examples, a small gap may still be present after application of compression force802. Further, support tool608may have any desirable contour. Yet further, in some illustrative examples, compression force802may not be applied to sheet606prior to beginning a machining operation.

Turning now toFIG.9, an illustration of a cross-sectional view of a machining system performing a machining operation on the sheet is depicted in accordance with an illustrative embodiment. In view900, machining tool614is performing a machining operation on sheet606. As depicted, machining tool614is drill bit622performing a drilling operation on sheet606. Compression force802is applied to sheet606as the drilling operation is performed on sheet606.

Compression force802is applied to sheet606to form region803of applied compressive force. Machining tool614performs drilling in region803.

Machining tool614is independently moveable relative to spring back control system616. More specifically, machining tool614is independently moveable relative to number of force generators618in first direction902parallel to number of force generators618. Between view800and view900, machining tool614has been moved in first direction902towards sheet606.

Turning now toFIG.10, an illustration of a cross-sectional view of a machining system performing a machining operation on the sheet is depicted in accordance with an illustrative embodiment. In view1000, drill bit622has completely perforated sheet606. In view1000, drill bit622is extending through sheet606.

In view1000, compression force802is applied to sheet606. Compression force802is applied in region803of sheet606. Due to compression force802still being applied to sheet606, sheet606is still in tension. Due to compression force802, spring back of sheet606following the machining operation is reduced. Spring back of sheet606following the machining operation under compression force802is less than spring back of sheet606after a drilling operation without compression force802. In view1000, the spring back of sheet606after drill bit622perforates sheet606is not visible. In other illustrative examples, the spring back of sheet606after drill bit622perforates sheet606may be visible.

Turning now toFIG.11, an illustration of a cross-sectional view of a machining system performing a machining operation on the sheet is depicted in accordance with an illustrative embodiment. In view1100, drill bit622has been retracted in first direction902from sheet606. Hole1102extends through sheet606. In view1100, compression force802is maintained on sheet606. As compression force802is removed from sheet606, tension will be removed from sheet606. As compression force802is removed from sheet606, spring back will occur in a controlled fashion. For example, at least one of the rate of the spring back or the initiation of spring back relative to machining operation is controlled.

In some illustrative examples, compression force802may be maintained on sheet606as roller625and roller627are rolled across surface702of sheet606. In these illustrative examples, compression force802is maintained as end effector612is moved relative to sheet606. In some of these illustrative examples, compression force802may be maintained as drill bit622performs machining operations on several locations of sheet606.

In other illustrative examples, compression force802is removed prior to moving end effector612relative to sheet606. In some of these illustrative examples, compression force802is applied prior to each instance of a machining operation and removed after each instance of the machining operation.

Turning now toFIG.12, an illustration of a perspective view of a machining system configured to reduce spring back following a machining operation is depicted in accordance with an illustrative embodiment. Machining system1200is a physical implementation of machining system100ofFIG.1. Machining system1200is configured to reduce spring back following a machining operation. Machining system1200comprises number of linear force generators1202, number of force loaded members1204coupled to number of linear force generators1202, and machining tool1206independently moveable relative to number of linear force generators1202in a first direction parallel to number of linear force generators1202. Number of force loaded members1204is configured to apply compression force to form a region of applied compressive force. Machining tool1206is positioned to perform a machining operation within the region.

As depicted, number of force loaded members1204is each equidistant from machining tool1206. As depicted, number of force loaded members1204comprises pad1208, pad1210, and pad1212. Number of linear force generators1202takes any desirable form. In some illustrative examples, number of linear force generators1202comprises at least one of a number of springs or a number of pneumatic cylinders.

Machining tool1206is independently moveable in a second direction perpendicular to number of linear force generators1202. As depicted, machining tool1206comprises drill bit1214having axis1216parallel to number of linear force generators1202.

As depicted, machining system1200takes the form of end effector1218. End effector1218is configured to reduce spring back following a machining operation.

Machining system1200comprises machining tool1206and spring back control system1220. Spring back control system1220comprises number of force generators1222and number of force loaded members1204coupled to number of force generators1222. Each force loaded member of number of force loaded members1204comprises a material contact surface. As depicted, pad1208of number of force loaded members1204has material contact surface1224. Pad1210has material contact surface1226and pad1212has material contact surface1228.

In end effector1218, each force generator of number of force generators1222is coupled to a different force loaded member of number of force loaded members1204. In end effector1218, each of number of force generators1222is coupled to a respective single force loaded member of pad1208, pad1210, or pad1212.

In this illustrative example, pad1208, pad1210, and pad1212form a triangle. As can be seen in this illustrative example, machining tool1206will perform a machining operation on a workpiece within a triangular region of compressive force formed by pad1208, pad1210, and pad1212. As can be seen in this illustrative example, machining tool1206will be positioned between pad1208, pad1210, and pad1212.

To reduce spring back following a machining operation using machining tool1206, pad1208, pad1210, and pad1212are placed in contact with the surface of a workpiece. A compression force is applied to the workpiece using number of force generators1222to form a region of applied compressive force. A machining operation will be performed in the region using machining tool1206while the compression force is applied to the sheet.

Turning now toFIG.13, an illustration of a flowchart of a method for controlling spring back of a sheet of material following a machining operation using a machining system is depicted in accordance with an illustrative embodiment. Method1300may be implemented in manufacturing environment102ofFIG.1using machining system100. Method1300may be implemented using machining system200ofFIGS.2and3. Method1300may be implemented using machining system400ofFIGS.4-5. Method1300may be implemented in manufacturing environment605using machining system600ofFIGS.6-11. Method1300may be implemented using machining system1200ofFIG.12.

Method1300applies a compression force to the sheet using a number of force generators coupled to a number of force loaded members in contact with the sheet to form a region of applied compressive force (operation1302). Each of the force loaded members comprises a respective material contact surface. The material contact surface takes the form of one of a moveable surface or a stationary surface. When the material contact surface takes the form of a moveable surface, material contact surface may be part of a roller. When the material contact surface takes the form of a stationary surface, the material contact surface may be part of a pad.

The number of force generators take any desirable form. In some illustrative examples, the number of force generators are a number of linear force generators.

Method1300completes a machining operation through the region of the surface of the sheet using a machining tool while the compression force is applied to the sheet (operation1304). The machining operation may be drilling, milling, countersinking, or any other desirable form of machining operation. Afterwards, method1300terminates.

By completing a machining operation while the compression force is applied, spring back following the machining operation is reduced or eliminated. Controlled spring back of the sheet occurs as compression force is removed from the sheet. By controlling at least one of the rate of the spring back or the timing of the spring back relative to the machining operation, at least one of the quality of the machining features or the life of the machining tool may be increased.

In some illustrative examples, the compression force is applied to the region of the sheet prior to performing the machining operation. In some illustrative examples, the compression force deflects the sheet such that the machining operation is performed on a desired location.

In some illustrative examples, applying the compression force to the region of the sheet comprises moving the number of force generators towards the surface of the sheet while the number of force loaded members is in contact with the surface of the sheet to compress the number of force generators (operation1306). In some illustrative examples, method1300moves the machining tool relative to the surface of the sheet while maintaining contact of the number of force loaded members with the surface of the sheet (operation1308). In some illustrative examples, moving the machining tool relative to the surface of the sheet while maintaining contact of the number of force loaded members with the surface of the sheet is performed to apply a machining operation to a second location within the region. In some illustrative examples, moving the machining tool relative to the surface of the sheet while maintaining contact of the number of force loaded members with the surface of the sheet is performed when the machining operation is a countersinking operation.

In some illustrative examples, moving the machining tool relative to the surface of the sheet comprises moving the machining tool relative to the surface while performing the machining operation (operation1310).

In some illustrative examples, method1300removes the machining tool from the sheet (operation1312). The compression force is removed from the sheet (operation1314). The machining tool and force loaded members are moved relative to the surface of the sheet after removing the machining tool and the compression force from the sheet (operation1316). A compression force is applied to a second portion of the sheet using the number of force generators coupled to the number of force loaded members to form a second region of applied compressive force (operation1318). The machining operation is performed through the second region of the surface of the sheet using the machining tool while the compression force is applied to the second portion of the sheet (operation1320).

Turning now toFIG.14, an illustration of a flowchart of a method of reducing spring back of a thin sheet during a machining operation is depicted in accordance with an illustrative embodiment. Method1400may be implemented in manufacturing environment102ofFIG.1using machining system100. Method1400may be implemented using machining system200ofFIGS.2and3. Method1400may be implemented using machining system400ofFIGS.4-5. Method1400may be implemented in manufacturing environment605using machining system600ofFIGS.6-11. Method1400may be implemented using machining system1200ofFIG.12.

Method1400deflects the thin sheet towards a support tool with an end effector (operation1402). Method1400performs the machining operation on the thin sheet while deflected (operation1404). Afterwards the method terminates.

In some illustrative examples, deflecting is performed by a number of biasing devices attached to a same end effector performing the machining operation (operation1406). In some illustrative examples, the number of biasing devices is part of a spring back control system of the end effector.

In some illustrative examples, deflecting the thin sheet comprises deflecting the thin sheet a distance as a function of a compression force applied to the thin sheet by a number of force loaded members (operation1408). The compression force applied is sufficient to temporarily deflect the thin sheet and lower than a force to permanently deflect the thin sheet.

In some illustrative examples, performing the machining operation comprises further deflecting the thin sheet by a machining force of the machining operation, wherein deflection from the machining force is less than deflection from the compression force applied by the number of force loaded members (operation1410). When the machining operation perforates the thin sheet and the machining force is no longer applied to the thin sheet, the spring back of the thin sheet is less because the thin sheet is still deflected by the compression force.

As used herein, the phrase “at least one of,” when used with a list of items, means different combinations of one or more of the listed items may be used, and only one of each item in the list may be needed. In other words, “at least one of” means any combination of items and number of items may be used from the list, but not all of the items in the list are required. The item may be a particular object, a thing, or a category.

For example, “at least one of item A, item B, or item C” may include, without limitation, item A, item A and item B, or item B. This example also may include item A, item B, and item C, or item B and item C. Of course, any combination of these items may be present. In other examples, “at least one of” may be, for example, without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or other suitable combinations.

The flowcharts and block diagrams in the different depicted embodiments illustrate the architecture, functionality, and operation of some possible implementations of apparatus and methods in an illustrative embodiment. In this regard, each block in the flowcharts or block diagrams may represent a module, a segment, a function, and/or a portion of an operation or step.

In some alternative implementations of an illustrative embodiment, the function or functions noted in the blocks may occur out of the order noted in the figures. For example, in some cases, two blocks shown in succession may be executed substantially concurrently, or the blocks may sometimes be performed in the reverse order, depending upon the functionality involved. Also, other blocks may be added, in addition to the illustrated blocks, in a flowchart or block diagram. Some blocks may be optional. For example, in method1300, operations1308through1322may be optional. As another example, in method1400, operations1406through1410may be optional.

Illustrative embodiments of the present disclosure may be described in the context of aircraft manufacturing and service method1500as shown inFIG.15and aircraft1600as shown inFIG.16. Turning first toFIG.15, an illustration of an aircraft manufacturing and service method is depicted in accordance with an illustrative embodiment. During pre-production, aircraft manufacturing and service method1500may include specification and design1502of aircraft1600inFIG.16and material procurement1504.

During production, component and subassembly manufacturing1506and system integration1508of aircraft1600takes place. Thereafter, aircraft1600may go through certification and delivery1510in order to be placed in service1512. While in service1512by a customer, aircraft1600is scheduled for routine maintenance and service1514, which may include modification, reconfiguration, refurbishment, or other maintenance and service.

Each of the processes of aircraft manufacturing and service method1500may be performed or carried out by a system integrator, a third party, and/or an operator. In these examples, the operator may be a customer. For the purposes of this description, a system integrator may include, without limitation, any number of aircraft manufacturers and major-system subcontractors; a third party may include, without limitation, any number of vendors, subcontractors, and suppliers; and an operator may be an airline, a leasing company, a military entity, a service organization, and so on.

With reference now toFIG.16, an illustration of an aircraft is depicted in which an illustrative embodiment may be implemented. In this example, aircraft1600is produced by aircraft manufacturing and service method1500ofFIG.15and may include airframe1602with plurality of systems1604and interior1606. Examples of systems1604include one or more of propulsion system1608, electrical system1610, hydraulic system1612, and environmental system1614. Any number of other systems may be included. Although an aerospace example is shown, different illustrative embodiments may be applied to other industries, such as the automotive industry.

Apparatuses and methods embodied herein may be employed during at least one of the stages of aircraft manufacturing and service method1500. One or more illustrative embodiments may be used during at least one of component and subassembly manufacturing1506, system integration1508, or maintenance and service1514ofFIG.15. For example, machining system100with spring back control system106may be used during component and subassembly manufacturing1506to form component162. As another illustrative example, machining system100with spring back control system106may be used to form a replacement component for use in maintenance and service1514. Machining system100may be used to manufacture portions of aircraft1600such as airframe1602or portions of interior1606.

The illustrative examples present machining systems and methods configured to reduce spring back following a machining operation. The illustrative examples provide a spring back control system configured to apply a compression force to a sheet. By applying the compression force to the sheet, a region of compressive force is formed. By performing a machining operation in the region of compressive force, spring back following completion of a machining operation is reduced or eliminated. By reducing or eliminating spring back, the quality of machined areas, such as holes or slots, is improved. By reducing or eliminating spring back, a risk to the machining tool is reduced.

By incorporating the spring back control system into the machining system, at least one of the complexity, the time, or the cost of securing of the sheet to the support tool may be reduced. For example, by applying a compression force to the sheet using the spring back control system, adhesive may not be used to secure the sheet to the support tool. As another example, by applying a compression force to the sheet using the spring back control system, additional mechanical or vacuum attachments to the support tool may not be used.

In some illustrative examples, a number of biasing devices apply a load to a thin sheet. By applying the load to the thin sheet, the thin sheet may reversibly deflect towards a support tool. After applying the load to the thin sheet, a machining operation is completed on the thin sheet. In some illustrative examples, the load is applied to the thin sheet prior to performing the machining operation. When the sheet is deflected prior to the machining operation, the location of a resulting feature created by the machining operation is desirably located. Deflecting the thin sheet prior to completing the machining operation reduces the spring back of the machining operation.

The description of the different illustrative embodiments has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Further, different illustrative embodiments may provide different features as compared to other illustrative embodiments. The embodiment or embodiments selected are chosen and described in order to best explain the principles of the embodiments, the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.