Controlling spring back of sheet of material following machining operation

Abstract

To provide a machining system configured to reduce spring back following machining operations.SOLUTION: A machining system (600) comprises a machining tool (614) and a spring back control system (616). The spring back control system (616) comprises a number of force generators (618) and a number of force loaded members (620) coupled to the number of force generators (618), each force loaded member (620) of the number of force loaded members comprising a material contact surface.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates generally to sheet machining, and more particularly to techniques for controlling springback in a sheet of material after machining. [Background technology]

[0002] In the manufacture of sheet parts, a sheet of material may be subjected to a machining operation such as drilling, milling, countersinking, or other desired operation. When the machining force of a drill bit is first applied to an unsupported portion of the sheet, the resulting scratch on the sheet is Due to the springback, it may not be possible to form a hole that meets the desired quality. The initial machining force applied by the drill bit and the resulting springback in the sheet can have adverse effects on the drill bit, including causing it to break.

[0003] It would therefore be desirable to provide a method and apparatus that takes into account at least some of the considerations discussed above, as well as other potential considerations. Summary of the Invention

[0004] An exemplary embodiment of the present disclosure provides a method for controlling springback in a sheet of material after machining using a machining system, including contacting a surface of the sheet with a predetermined number of load receivers, applying a compressive force to the sheet using a predetermined number of force generating devices connected to the predetermined number of load receivers to form a compressive force region, and performing a machining operation using a machining tool to penetrate the surface of the sheet through the region while the compressive force is applied to the sheet.

[0005] Another exemplary embodiment of the present disclosure provides a machining system configured to reduce springback after machining, the machining system including a machining tool, a springback control system including a number of force generating devices and a number of load receiving members connected to the number of force generating devices, each load receiving member having a material contact surface.

[0006] Yet another exemplary embodiment of the present disclosure provides a machining system configured to reduce springback after machining, the machining system including a number of linear force generators, a number of load receivers connected to the number of linear force generators, and a machining tool movable independently of the number of linear force generators, the number of load receivers configured to apply a compressive force to define a compressive force region, and the machining tool positioned to perform machining within the region.

[0007] Yet another exemplary embodiment of the present disclosure provides a method for reducing springback in a thin-walled sheet after machining, comprising: deflecting the thin-walled sheet toward a support tool with an end effector; and performing a machining operation on the thin-walled sheet while the thin-walled sheet is deflected.

[0008] These features and functions can be achieved individually in various embodiments of the present disclosure or can be combined in yet further embodiments, the details of which will become apparent with reference to the following description and accompanying drawings. [Brief explanation of the drawings]

[0009] The novel features believed characteristic of the exemplary embodiments are set forth in the appended claims. However, the exemplary embodiments, as well as their preferred modes of use, objects and These features will become more apparent from the following detailed description of exemplary embodiments of the present disclosure, when read in conjunction with the accompanying drawings.

[0010] [Figure 1] FIG. 1 is a block diagram illustrating a manufacturing environment in which a machining system configured to reduce springback after machining is used in accordance with an illustrative embodiment. [Figure 2] FIG. 1 illustrates a perspective view of a machining system configured to reduce springback after machining in accordance with an exemplary embodiment. [Figure 3] FIG. 1 illustrates a bottom view of a machining system configured to reduce springback after machining in accordance with an exemplary embodiment. [Figure 4] FIG. 1 illustrates a side view of a machining system configured to reduce springback after machining in accordance with an exemplary embodiment. [Figure 5] FIG. 1 is a front view of a machining system configured to reduce springback after machining in accordance with an exemplary embodiment; [Figure 6] FIG. 1 is a front view of an exemplary embodiment of a machining system positioned above a seat. [Figure 7] FIG. 1 is a front view of an exemplary embodiment of a machining system with a load receiver in contact with a sheet; [Figure 8] FIG. 1 is a front view illustrating a load receiver of a machining system applying a compressive force to a sheet in accordance with an exemplary embodiment; [Figure 9] 1 is a cross-sectional view illustrating a machining system according to an exemplary embodiment machining a sheet; [Figure 10] 1 is a cross-sectional view illustrating a machining system according to an exemplary embodiment machining a sheet; [Figure 11] 1 is a cross-sectional view illustrating a machining system according to an exemplary embodiment machining a sheet; [Figure 12] FIG. 1 illustrates a perspective view of a machining system configured to reduce springback after machining in accordance with an exemplary embodiment. [Figure 13]1 is a flowchart illustrating a method for controlling springback in a sheet of material after machining with a machining system in accordance with an exemplary embodiment. [Figure 14] 1 is a flowchart illustrating a method for reducing springback in a thin-walled sheet during machining in accordance with an exemplary embodiment. [Figure 15] 1 is a block diagram illustrating a method of manufacturing and using an aircraft in accordance with an illustrative embodiment; FIG. [Figure 16] 1 is a block diagram illustrating an aircraft in which an illustrative embodiment may be implemented; DETAILED DESCRIPTION OF THE INVENTION

[0011] The exemplary embodiments recognize and take into account one or more different considerations. The exemplary embodiments recognize and take into account that a sheet is constrained against a backing plate style support tool before the sheet is processed. To avoid the constraint of the sheet interfering with processing, often the outer edge of the sheet is constrained while the remainder of the sheet is unconstrained. Even if the outer edge of the sheet is constrained, the remainder of the sheet may include a portion that curves and does not contact the support surface of the support tool. The portion of the sheet that is not contacting the support surface is unsupported. The sheet is partially machined while the outer edge is constrained against the support tool. The portion of the sheet that is machined may not contact the support tool and may be unsupported.

[0012] The exemplary embodiment recognizes and takes into account that machining an unsupported portion of a sheet can cause springback. For example, when drilling a hole using a conventional drilling system, the drill bit first contacts the unsupported side of the sheet and applies pressure to the sheet. The drill bit applies pressure or machining force to initially push the sheet back. The sheet is first compressed against the support tool and then penetrated. Once the sheet is completely penetrated, the elastic energy causes the sheet to quickly return to its free state. This springback of the sheet is uncontrolled.

[0013] During machining, the sheet is pressed towards the support tool by the machining force of the drill bit, and when the drill bit penetrates the sheet, the sheet is released from the pressing force of the drill bit and springs back to its original position.

[0014] The exemplary embodiments recognize and take into account that it is desirable for the support tool to faithfully mirror the shape of the sheet. The exemplary embodiments recognize and take into account that the shape of the sheet placed on the support tool may not be accurately mirrored across the entire surface of the support tool. The exemplary embodiments recognize and take into account that the support surface of the support tool may not be planar in order to support the sheet. The exemplary embodiments recognize and take into account that restraining the sheet against the support tool may result in a gap between the support surface and the sheet.

[0015] The exemplary embodiments recognize and take into account that the support surface of the support tool in some examples is non-planar in order to support the sheet. In some exemplary examples, the non-planar support tool is concave. If the support surface is non-planar, restraining the outer edge of the sheet will cause the remainder of the sheet to curve, resulting in a portion of the sheet not contacting the support surface of the support tool. The exemplary embodiments recognize and take into account that a gap may form between the sheet and the support tool depending on the shape of the sheet in combination with the shape of the support tool. The exemplary embodiments recognize and take into account that a gap may form even if energy that causes springback is stored in the sheet.

[0016] The exemplary embodiment recognizes and takes into account that machining into an unsupported portion of the sheet may result in machining in an undesired location. The exemplary embodiment recognizes and takes into account that it is desirable for the sheet to be in contact with a support surface in order to form the machining irregularities in the desired location.

[0017] The illustrative embodiments also recognize and take into account that a temporary adhesive can be used to fasten a sheet of material to a support tool to reduce springback after machining. However, adhesive residue can adhere to machining tools, such as drill bits. Adhesion of adhesive residue to the machining tool can adversely affect at least one of the life of the machining tool and the quality of the manufactured part. For example, adhesive residue can adversely affect the quality of holes drilled in the manufactured part. The illustrative embodiments recognize and take into account that applying adhesive adds time and cost to the manufacturing process.

[0018] Additionally, the adhesive used to secure the sheet of material to the support tool should be suitable for direct application, for example, depending on the type of material of the sheet and the type of material of the support tool. It is undesirable to use an adhesive that could cause damage to either the sheet or the support tool. Furthermore, depending on the material of the sheet, the amount of adhesive that can be used may be limited.

[0019] In some manufacturing processes, a sheet is placed under vacuum to secure it to a support tool. However, conventional vacuum plates with vacuum grooves on the outer edge do not allow the vacuum to reach the center of the sheet where machining takes place. In machining processes such as these, conventional vacuum plates with vacuum grooves in the areas to be machined are less effective.

[0020] The exemplary embodiment recognizes and takes into account that conventional methods for reducing springback include restraining the sheet against a support tool, which includes increasing the support area at the outer edges of the sheet.

[0021] The exemplary embodiment recognizes and takes into account that after a machining tool penetrates the sheet and the machining forces acting on the sheet are released, uncontrolled release of tension in the sheet that was placed in tension by the machining forces will result in uncontrolled springback. The exemplary embodiment recognizes and takes into account that if the release of tension can be controlled, springback can be controlled.

[0022] Exemplary embodiments provide machining systems and methods for reducing springback during machining. In exemplary embodiments, a compressive force (pressing force) is applied to a surface of a sheet as the surface of the sheet is machined. The application of the compressive force can reduce or eliminate springback in the sheet after machining. In some exemplary embodiments, a number of biasing devices apply a load to the sheet prior to machining to deflect the sheet, thereby limiting springback after machining to within desired limits. When the compressive force is released, the sheet undergoes controlled springback to return to its original shape. At least one of the rate of springback and the timing of the onset of springback relative to machining is controlled.

[0023] 1, a block diagram of a manufacturing environment is shown in which a machining system configured to reduce springback after machining according to an exemplary embodiment may be used. A machining system 100 in a manufacturing environment 102 is configured to reduce springback after machining.

[0024] The machining system 100 includes a machining tool 104 and a springback control system 106. The springback control system 106 includes a predetermined number of force generating devices 108 and a predetermined number of force loaded members connected to the predetermined number of force generating devices 108. Each of the load receiving members in the number of load receiving members 110 is made of material For example, the load receiving member 111 has a material contact surface 113.

[0025] As used herein, a "predetermined number" of items means one or more items. For example, a predetermined number of load receivers means one or more load receivers.

[0026] The material contact surface 113 is constructed of a desired material. The material contact surface 113 is configured to not adversely affect the surface 122 of the sheet 120. In one embodiment, the shape of the material contact surface 113 is selected to prevent undesired scratching, bending, or marking of the surface 122 of the sheet 120. In another embodiment, the material of the material contact surface 113 is selected to prevent undesired scratching, bending, or marking of the surface 122 of the sheet 120. In another exemplary embodiment, the material of the material contact surface 113 is selected to slide relative to the surface 122. In another exemplary embodiment, the material of the material contact surface 113 is selected to grip the surface 122 and prevent movement of the material contact surface 113.

[0027] Machining tool 104 may include any desired type of tool. In some exemplary embodiments, machining tool 104 may be a cutting tool. In one exemplary embodiment, machining tool 104 may be a drill bit 112. In other exemplary embodiments, machining tool 104 may be selected from a blade, punch, milling cutter, or other desired cutting tool. In the illustrated embodiment, the machining tool 104 is selected from a joining machine, a welding machine, or any other desired type of tool.

[0028] In some exemplary embodiments, the machining tool 104 is movable independently of the springback control system 106. In some exemplary embodiments, the machining tool 104 is movable independently of the number of force generating devices 108. In one exemplary embodiment, the machining tool 104 is movable in a first direction 114 independently of the springback control system 106. The first direction 114 is parallel to the direction in which the compressive force 116 is applied. The compressive force 116 applied to the sheet 120 by the springback control system 106 is parallel to the first direction 114 and is also parallel to the force applied to the sheet 120 by the machining tool 104. In another exemplary embodiment, the machining tool 104 is movable in a second direction 118 perpendicular to the first direction 114 independently of the springback control system 106.

[0029] With the machining tool 104 movable independently of the springback control system 106, machining operations that require the machining tool 104 to move in the second direction 118, such as slotting or countersinking, can be performed using the machining tool 104. With the machining tool 104 movable independently of the springback control system 106, multiple machining operations can be repeatedly performed using the machining tool 104 without moving the springback control system 106 relative to the sheet 120.

[0030] The springback control system 106 applies a compressive force 116 to the sheet 120. The springback control system 106 applies the compressive force 116 to a surface 122 of the sheet 120 to form a compressive force region 124. A machining operation, such as a machining operation 126, is performed in the region 124. The machining operation can be any desired operation, such as drilling, milling, countersinking, or other desired machining operation.

[0031] Sheet 120 is comprised of material 128. Material 128 can be any desired material capable of elastic deformation 130. During machining 126, sheet 120 is placed in tension by a force applied by machining tool 104 until machining tool 104 penetrates sheet 120. In some illustrative embodiments, material 128 is one of a metal 132 or a composite material 134. If material 128 is a composite material 134, composite material 134 is hardened or partially hardened.

[0032] In some illustrative examples, sheet 120 is referred to as a thin sheet 136. Sheet 120 is referred to as a thin sheet 136 because sheet 120 is thin enough that when processing forces act on sheet 120 during machining 126, sheet 120 flexes even without compressive force 116.

[0033] The sheet 120 is constrained against a support tool 138. In some exemplary embodiments, when the sheet 120 is constrained against the support tool 138, a gap 140 is formed between a portion of the sheet 120 and a support surface 142 of the support tool 138. In some exemplary embodiments, the gap 140 is formed by the support surface 142 including a concave curvature 144. The gaps 140 are not formed on the entire backside of the sheet 120, but at least on the backside of some of the locations where the machining 126 is performed.

[0034] If machining 126 is performed without applying compressive force 116 to surface 122 from springback control system 106, springback 146 after machining 126 will generate undesirable forces. If machining 126 is performed without applying compressive force 116 to surface 122 from springback control system 106, springback 146 will be suppressed. The springback 146 occurring after the machining 126 may be reduced by performing the machining 126 with the compressive force 116 applied to the surface 122. The springback control system 106 may reduce the springback 146 after the machining 126 below a desired threshold. Specifically, the springback 146 when the machining 126 is performed with the compressive force 116 applied may be less than the springback when the machining 126 is performed without the compressive force 116 applied. In some illustrative examples, performing the machining 126 with the compressive force 116 applied may eliminate the springback 146 after the machining 126.

[0035] The compressive force 116 applied to the surface 122 is sufficient to reduce springback 146 of the sheet 120 after machining 126 to a desired level, but is not so great as to permanently deform the sheet 120. In some exemplary embodiments, the compressive force 116 is sufficient to bring the compressively applied area 124 of the sheet 120 into contact with the support surface 142 of the support tool 138. The number of force generating devices 108 is selected to apply a desired amount of compressive force 116. In some exemplary embodiments, the number of force generating devices 108 are removable and replaceable, thereby allowing force generating devices of a desired strength to be installed in the springback control system 106.

[0036] In some illustrative embodiments, when a compressive force 116 is applied to surface 122 of sheet 120, sheet 120 deflects toward support surface 142 of support tool 138. As sheet 120 deflects toward support surface 142, gap 140 decreases. Maintaining compressive force 116 after machining 126 can control the return of sheet 120 to its original shape.

[0037] In a state in which the sheet 120 has been deflected toward the support surface 142 by the compressive force 116, the degree to which the sheet 120 deflects toward the support surface 142 due to the processing force during the machining process 126 is less than the deflection due to the compressive force 116. The machining process 126 of the sheet 120 is performed with the compressive force 116 applied to the sheet 120. When the machining tool 104 penetrates the sheet 120, the processing force acting on the sheet 120 is eliminated, and the deflection of the sheet 120 due to the machining process 126 returns to its original shape due to springback 146. Because the compressive force 116 is still acting, the springback 146 is reduced. The compressive force 116 is removed after the machining process 126 is completed. When the compressive force 116 is removed, the sheet 120 returns to its original shape due to elastic deformation 130.

[0038] When the compressive force 116 is removed and the sheet 120 returns to its original shape, springback 147 occurs in the sheet 120. This springback 147 is also referred to as "controlled springback." At least one of the rate of springback 147 and the timing of the onset of springback 147 relative to the machining process 126 is controlled. In some exemplary embodiments, the compressive force 116 is removed locally, resulting in localized springback 147. However, the compressive force 116 can be moved along the sheet 120 to maintain the compressive force 116 on the sheet 120. In some exemplary embodiments, when the compressive force 116 is removed from the sheet 120, springback 147 occurs throughout the entire sheet 120.

[0039] The springback control system 106 applies a compressive force 116. The number of force generators 108 of the springback control system 106 provide forces to the number of load receivers 110 connected to the number of force generators 108. The number of force generators 108 can take any form. In some exemplary embodiments, the number of force generators 108 is a number of linear force generators 148. The number of linear force generators 148 is a number of linear force generators 148. The predetermined number of linear force generators 148 are configured to apply a directional force to the sheet 120. However, the predetermined number of linear force generators 148 need not be linear. In some exemplary embodiments, the predetermined number of linear force generators 148 are at least one of a predetermined number of springs or a predetermined number of pneumatic cylinders. In some exemplary embodiments, the force generators 108 are also referred to as biasing devices 149. The predetermined number of biasing devices 149 generate a compressive force 116 that is applied to the sheet 120 to reduce springback 146 caused by the machining operation 126. The application of the compressive force 116 reduces tension generated in the sheet 120 during the machining operation 126. The application of the compressive force 116 moves the sheet 120 toward the support tool 138. In some exemplary embodiments, the compressive force 116 acting on the sheet 120 is maintained while the machining operation 126 is performed multiple times on the sheet 120. In some exemplary embodiments, the compressive force 116 acting on the sheet 120 is removed after each machining operation 126.

[0040] Each load receiver in the predetermined number of load receivers 110 is associated with a corresponding force-generating device in the predetermined number of force-generating devices 108. In some exemplary embodiments, multiple force-generating devices in the predetermined number of force-generating devices 108 are connected to one load receiver in the predetermined number of load receivers 110. In some exemplary embodiments, each force-generating device in the predetermined number of force-generating devices 108 is connected to one load receiver in the predetermined number of load receivers 110.

[0041] The number of load receiving members 110 includes at least one of a number of rollers or a number of pads. Each load receiving member in the number of load receiving members 110 has a material contact surface 113. Each material contact surface 113 is one of a roller 150 or a pad 152.

[0042] In some exemplary embodiments, when material contact surface 113 is a roller 150, roller 150 is maintained in contact with surface 122 of sheet 120 while machining system 100 moves in second direction 118. In some exemplary embodiments, when material contact surface 113 is a roller 150, roller 150 is maintained in contact with surface 122 of sheet 120 while machining 126 is performed at multiple locations on sheet 120.

[0043] In some exemplary embodiments, if the material contact surface 113 is a pad 152, the pad 152 is removed from the surface 122 of the sheet 120 before the machining system 100 moves in the second direction 118. In some exemplary embodiments, if the material contact surface 113 is a pad 152, the machining tool 104 performs a machining operation 126 while moving relative to the pad 152. In some exemplary embodiments, the machining tool 104 performs countersinking, routing, slotting, or , and perform other desired machining.

[0044] In some demonstrative embodiments, the number of load bearing members 110 and the machining tool 104 move in a first direction 114 toward the surface 122 while simultaneously performing the machining operation 126. In some demonstrative embodiments, the machining tool 104 moves in the first direction 114 to perform the machining operation 126 after the number of load bearing members 110 contact the surface 122 and apply the compressive force 116.

[0045] In some exemplary embodiments, the number of load receivers 110 includes a plurality of load receivers. In some of these exemplary embodiments, the number of load receivers 110 applies a compressive force 116 to a surface 122 of the sheet 120, forming a compressive force area 124. In these exemplary embodiments, region 124 is substantially between the predetermined number of load receivers 110. In these exemplary embodiments, the predetermined number of load receivers 110 are removed from surface 122 before machining system 100 moves in second direction 118. In these exemplary embodiments, the predetermined number of load receivers 110 are removed from contact with sheet 120 after dampening springback 146 due to machining 126.

[0046] In some illustrative embodiments, the predetermined number of load receiving members 110 includes a single load receiving member. In some of these illustrative embodiments, the predetermined number of load receiving members 110 includes a single pad 152. In these illustrative embodiments, the predetermined number of load receiving members 110 includes a pad 152 configured to form a working envelope 153 for the machining tool 104. When the predetermined number of load receiving members 110 includes a pad 152 that forms the working envelope 153, the machining tool 104 performs the machining operation 126 in the working envelope 153. In one illustrative embodiment, the machining tool 104 is a drill bit 112 that penetrates the working envelope 153 to perform the machining operation 126 on the sheet 120. In some illustrative embodiments, the machining tool 104 performs the machining operation 126 at multiple locations on the sheet 120 without moving the pad 152.

[0047] In some exemplary embodiments, each of the number of load receivers 110 further includes a linear bearing 154 and a carriage 156. When the linear bearings 154 and carriages 156 are included, in some exemplary embodiments, the movement of the number of load receivers 110 is limited to a first direction 114. When the linear bearings 154 and carriages 156 are included, in some exemplary embodiments, the movement of the number of load receivers 110 is limited to a second direction 118. When the linear bearings 154 and carriages 156 are included, the direction of application of the compressive force 116 is limited to the first direction 114.

[0048] In some demonstrative embodiments, the machining system 100 includes a number of linear force generators 148, a number of load receivers 110 connected to the number of linear force generators 148 and configured to apply a compressive force 116 to define a compressive force acting region 124, and a machining tool 104 movable in a first direction 114 parallel to the number of linear force generators 148, independent of the number of linear force generators 148. The machining tool 104 is positioned to perform a machining operation 126 in the region 124.

[0049] In some illustrative embodiments, each of the predetermined number of load receivers 110 is equidistant from the machining tool 104. In one illustrative embodiment, the predetermined number of load receivers 110 includes three load receivers arranged in a triangle. In this illustrative embodiment, the machining tool 104 may be located at the center of the triangle formed by the predetermined number of load receivers 110. In another illustrative embodiment, the predetermined number of load receivers 110 includes two load receivers. In this illustrative embodiment, the machining tool 104 may be located between the predetermined number of load receivers 110. In yet another illustrative embodiment, the predetermined number of load receivers 110 includes four load receivers arranged in a rectangle or square. In this illustrative embodiment, the machining tool 104 is located at the center of the rectangle or square formed by the four load receivers.

[0050] In some illustrative embodiments, number of load bearing members 110 include pads 152 configured to form working volumes 153 of machining tool 104. In these illustrative embodiments, pads 152 are also referred to as "feet." In these illustrative embodiments, pads 152 may be connected to multiple force generating devices of number of force generating devices 108.

[0051] In some exemplary embodiments, the machining tools 104 are independently movable in a second direction 118 perpendicular to the number of linear force generators 148. When the machining tools 104 are independently movable in the second direction 118, the machining tools 104 can move independently along the surface 122 of the sheet 120. In some exemplary embodiments, the machining tools 104 move in the second direction 118 while the number of load bearing members 110 contact the surface 122 and apply a compressive force 116. In these exemplary embodiments, the machining tools 104 are used to form slots, grooves, holes, or other desired irregularities that are larger than the machining tool 104. In some exemplary embodiments, the machining tool 104 includes a drill bit 112 having an axis 158 parallel to the number of linear force generators 148. In some exemplary embodiments, the machining tool 104 includes a drill bit 112 having an axis 158 parallel to the first direction 114.

[0052] In some exemplary embodiments, the machining system 100 takes the form of an end effector 160. In some exemplary embodiments, the end effector 160 is connected to a desired robotic device, such as a robotic arm.

[0053] Machining system 100 performs machining operations 126 on sheet 120 to produce part 162. Part 162 is a part of a desired platform. The platform may be, for example, a vehicle, a mobile platform, a fixed platform, a terrestrial structure, an aquatic structure, or a space structure. More specifically, the platform may be a surface ship, a tanker, a personnel carrier, a train, a spacecraft, a space station, a satellite, a submarine, an automobile, a power plant, a bridge, a dam, a home, a manufacturing facility, a building, or other suitable platform. In some illustrative embodiments, the platform is an aircraft. In these illustrative embodiments, part 162 is an aircraft part 164.

[0054] The component 162 has at least one characteristic formed by machining 126 with the machining tool 104. For example, the component 162 may have slots, grooves, holes, or other desired characteristic. In some illustrative examples, the component 162 is a perforated component. In some illustrative examples, the component 162 is a damper 166. The damper 166 may be an acoustic damper, a pressure damper, or another type of damper. In some illustrative examples, the component 162 is a face sheet of a sandwich panel structure. The manufacturing environment 102 and machining system 100 illustrated in FIG. 1 are not intended to imply physical or architectural limitations to the manner in which illustrative embodiments may be implemented. Other components may be used in addition to or in place of the illustrated components. Configurations may also be possible in which some components are not required. Additionally, the blocks are presented to represent some functional components. One or more of these blocks may be combined, divided, or combined and then divided to form different blocks.

[0055] For example, although the figures show one load receiver 111 in the number of load receivers 110, the number of load receivers 110 can include any desired number of load receivers. For example, the number of load receivers 110 can include two, three, four, or more than four load receivers. Each load receiver in the number of load receivers 110 includes a pad or a roller.

[0056] As another example, machining system 100 may include other components and systems other than the illustrated machining system 100. For example, machining system 100 may include a debris removal system for removing debris generated during machining 126. As another example, machining system 100 may include utility connections and other components supporting machining system 100. In yet another embodiment, material 128 may be any other type of material capable of elastic deformation 130, such as a polymer material.

[0057] Although not shown, in some example embodiments, the springback control system 106 may further include a force adjuster that adjusts the magnitude of the applied compressive force 116. The force adjuster may be manual or automatic.

[0058] Additionally, although only one end effector 160 is shown in the figures, in some illustrative embodiments, the machining system 100 may include multiple end effectors. In some illustrative embodiments, the springback control system 106 is part of a first end effector and the machining tool 104 is part of a second end effector.

[0059] Referring to FIG. 2, a perspective view of an exemplary embodiment of a machining system configured to reduce post-machining springback is shown. The machining system 200 is a physical implementation of the machining system 100 of FIG. 1. The machining system 200 is configured to reduce post-machining springback. The machining system 200 reduces the springback caused by machining by applying a compressive force to the sheet until machining is complete. Once the machining force is removed, the post-machining springback is reduced to below a desired threshold. Once the compressive force is removed from the sheet, controlled springback occurs.

[0060] The machining system 200 includes a number of linear force generators 202, a number of load receivers 204 connected to the number of linear force generators 202, and a machining tool 206 movable in a first direction 208 parallel to the number of linear force generators 202, independently of the number of linear force generators 202. The number of load receivers 204 are configured to apply a compressive force to define an area where the compressive force acts. The machining tool 206 is positioned to perform machining within this area.

[0061] As shown, the load receiving member 204 is spaced equidistant from the machining tool 206. As shown, the load receiving member 204 includes a pad 210 configured to define a working volume 212 for the machining tool 206. The number of force generating devices 202 may take any form. In some illustrative examples, the number of linear force generating devices 202 includes at least one of a number of springs or a number of pneumatic cylinders.

[0062] The machining tool 206 is independently movable in a second direction 214 that is perpendicular to the number of linear force generators 202. As shown, the machining tool 206 includes a drill bit 216 having an axis 218 that is parallel to the number of linear force generators 202.

[0063] As shown, the machining system 200 takes the form of an end effector 220. The end effector 220 is configured to reduce springback after machining.

[0064] The machining system 200 includes a machining tool 206 and a springback control system 222. The springback control system 222 includes a number of force generating devices 224 and a number of load receivers 204 connected to the number of force generating devices 224. Each load receiver in the number of load receivers 204 has a material contact surface. In the illustrated example, pads 210 of the number of load receivers 204 have the material contact surface.

[0065] In the end effector 220, a plurality of the force generating devices of the predetermined number of force generating devices 224 are connected to one of the predetermined number of load receiving members 204. In the end effector 220, each of the predetermined number of force generating devices 224 is connected to one of the load receiving members including the pad 210.

[0066] Referring now to Figure 3, a bottom view of an exemplary embodiment of a machining system configured to reduce springback after machining is shown. View 300 shows a working volume 212 defined by a pad 210. As can be seen in view 300, a machining tool 206 moves in a first direction 208, shown in Figure 2, through the working volume 212 to machine a workpiece. The first direction 208, shown in Figure 2, moves from outside the plane of the paper into and out of the plane of the paper in view 300.

[0067] To reduce springback after machining with the machining tool 206, the pad 210 is placed in contact with the surface of the workpiece. A number of force generating devices 224 apply a compressive force to the workpiece, creating a compressive zone. With the sheet under compressive force, machining is performed in the zone using the machining tool 206.

[0068] Referring now to Figure 4, a side view of an exemplary embodiment of a machining system configured to reduce springback after machining is shown. Machining system 400 is a physical implementation of machining system 100 of Figure 1. Machining system 400 is a second non-limiting example of a physical implementation of machining system 100 of Figure 1. Machining system 400 is configured to reduce springback after machining.

[0069] The machining system 400 includes a machining tool 402 and a springback control system 404. The springback control system 404 includes a number of force generating devices 406 and a number of load receiving members 408 connected to the number of force generating devices 406. Each load receiving member in the number of load receiving members 408 has a material contact surface.

[0070] For example, load receiver 410 of number of load receivers 408 has a material contact surface 412. Each material contact surface is one of a roller or a pad. Material contact surface 412 takes the form of a roller 414.

[0071] As shown, each of the number of load receivers 408 in the machining system 400 includes a linear bearing and a carriage. For example, load receiver 410 includes a linear bearing 416 and a carriage 418. The linear bearing 416 and carriage 418 limit the movement of load receiver 410 in a first direction 420.

[0072] The machining system 400 includes a number of linear force generators 422, a number of load receivers 408 connected to the number of linear force generators 422 and configured to apply a compressive force to define a compressive field, and a machining tool 402 movable independently of the number of linear force generators 422 in a first direction 420 parallel to the number of linear force generators 422, the machining tool 402 being positioned to perform machining within the field. In some example embodiments, the machining tool 402 is movable independently in a second direction perpendicular to the number of linear force generators 422.

[0073] Referring now to Figure 5, a front view of an exemplary embodiment of a machining system configured to reduce springback after machining is shown. View 500 shows a front view of the machining system 400 of Figure 4.

[0074] Viewed in view 500 is load receiver 502. Load receiver 502 of number of load receivers 408 has a material contacting surface 504. Material contacting surface 504 takes the form of rollers 506.

[0075] In this illustrative example, each load receiver in number of load receivers 408 is associated with a corresponding force generator in number of force generators 406. For example, force generator 508 is associated with load receiver 410, and force generator 510 is associated with load receiver 502.

[0076] Each of force generating devices 508 and force generating devices 510 provides a force of an appropriate magnitude to suppress springback of the sheet of material after machining. Each of force generating devices 508 and force generating devices 510 is selected based on, for example, the magnitude of the desired force. As shown, number of force generating devices 406 further includes force adjusting devices 518 and force adjusting devices 520. As shown, force adjusting devices 518 and force adjusting devices 520 can be loosened or tightened to adjust the preload applied to number of force generating devices.

[0077] As shown, the machining tool 402 includes a drill bit 512. As shown, the drill bit 512 has an axis 514. As shown, the number of force generators 406 take the form of a number of linear force generators 422. As shown, the axis 514 is parallel to the number of linear force generators 422. As shown, the machining tool 402 is disposed between the roller 414 and the roller 506. As shown, each of the number of load receivers 408 is disposed equidistantly from the machining tool 402. In some illustrative embodiments, each of the number of load receivers 408 is not disposed equidistantly from the machining tool 402.

[0078] As shown, the machining tool 402 includes a drill bit 512 having an axis 514 parallel to a number of linear force generators 422. In some example embodiments, the machining tool 402 is movable independently of the springback control system 404.

[0079] As shown, the number of linear force generators 422 includes at least one of a number of springs or a number of pneumatic cylinders. As shown, the number of linear force generators 422 is a number of springs 516.

[0080] Referring now to Figure 6, a front view of an exemplary embodiment of a machining system positioned above a seat is shown. Machining system 600 is a physical implementation of machining system 100 of Figure 1. Machining system 600 may be identical to machining system 400 of Figures 4-5.

[0081] In view 602, machining system 600 is positioned above workpiece 604 in manufacturing environment 605. Workpiece 604 takes the form of a sheet 606. Sheet 606 is associated with a support tool 608. Sheet 606 is associated with support tool 608 by being constrained to support tool 608. An outer edge (not shown) of sheet 606 is fastened to support tool 608, thereby constraining sheet 606 to support tool 608. View 602 shows the portion of sheet 606 that will undergo machining.

[0082] The outer edge of the sheet 606 is not machined. Note that the description that the outer edge is fixed is merely an example, and any portion of the sheet 606 may be restrained against the support tool 608. A portion 610 of the sheet 606 is not in contact with the support tool 608. The portion 610 of the sheet 606 is not supported.

[0083] The machining system 600 takes the form of an end effector 612. The end effector 612 is configured to reduce springback after machining. The machining system 600 includes a machining tool 614 and a springback control system 616. The springback control system 616 includes a number of force generating devices 618 and a number of load receivers 620 connected to the number of force generating devices 618. Each load receiver in the number of load receivers 620 has a material contact surface. As shown, each material contact surface is a roller. For example, the load receiver 624 includes a roller 625. In another example, the load receiver 628 includes a roller 627.

[0084] As shown, machining tool 614 includes drill bit 622. Each load receiver in number of load receivers 620 is associated with a corresponding one of predetermined number of force generators 618. For example, load receiver 624 in number of load receivers 620 is associated with force generator 626 in predetermined number of force generators 618. In another example, load receiver 628 in number of load receivers 620 is associated with force generator 630 in predetermined number of force generators 618.

[0085] Before machining the sheet 606 with the drill bit 622, a compressive force is applied to the sheet 606 by the springback control system 616. Applying the compressive force by the springback control system 616 can reduce springback of the sheet 606 that occurs when machining the sheet 606. The compressive force is applied in anticipation of the occurrence of springback of the sheet 606.

[0086] 7, a front view of an exemplary embodiment of a machining system with a load receiver in contact with a sheet is shown. In view 700, rollers 625 and 627 are in contact with surface 702 of sheet 606. Machining tool 614 is not in contact with surface 702. In view 700, a gap 704 is present between sheet 606 and support tool 608.

[0087] In view 700, there is no compressive force yet acting on surface 702. In view 700, rollers 625 and 627 are in contact with surface 702 but are not exerting any force on sheet 606.

[0088] 8, a front view of an exemplary embodiment of a machining system with load receivers applying a compressive force to a sheet is shown. In view 800, a compressive force 802 is applied to sheet 606 using a number of force generators 618 connected to a number of load receivers 620, creating a compressive force area 803.

[0089] In illustration 800, a compressive force 802 causes the sheet 606 to deflect toward the support tool 608. The deflection of the sheet 606 toward the support tool 608 places the sheet 606 in tension. The deflection of the sheet 606 toward the support tool 608 reduces the gap 704 between the sheet 606 and the support tool 608 in illustration 800 compared to illustration 700 of FIG. 7. In illustration 800, there is no visible gap between the sheet 606 and the support tool 608. However, illustration 800 is not intended to imply physical or architectural limitations on how illustrative embodiments may be implemented. In other illustrative examples, a small gap may remain even with the application of the compressive force 802. Furthermore, the support tool 608 has a desired contoured shape. Furthermore, in some illustrative examples, the compressive force 802 is not applied to the sheet 606 before machining begins.

[0090] Referring now to FIG. 9, a machining system according to an exemplary embodiment machines a sheet. 9 shows a cross-sectional view of a sheet 606 undergoing machining. In view 900, a machining tool 614 is performing a machining operation on the sheet 606. As shown, the machining tool 614 is a drill bit 622, which is drilling into the sheet 606. The drilling of the sheet 606 is performed while a compressive force 802 is acting on the sheet 606.

[0091] Compressive force 802 is applied to sheet 606, creating a compressive region 803. Machining tool 614 drills into region 803.

[0092] The machining tool 614 is movable independently of the springback control system 616. More specifically, the machining tool 614 is movable independently of the number of linear force generators 618 in a first direction 902 parallel to the number of linear force generators 618. Between illustration 800 and illustration 900, the machining tool 614 is moving in the first direction 902 toward the sheet 606.

[0093] 10, a cross-sectional view of an exemplary embodiment of a machining system is shown machining a sheet. In view 1000, drill bit 622 has drilled completely through sheet 606. In view 1000, drill bit 622 has penetrated sheet 606.

[0094] In illustration 1000, a compressive force 802 is applied to sheet 606. Compressive force 802 acts on region 803 of sheet 606. As compressive force 802 continues to act on sheet 606, sheet 606 is in tension. Compressive force 802 can reduce or eliminate springback after machining sheet 606. The springback of sheet 606 after machining with compressive force 802 is less than the springback of sheet 606 after drilling without compressive force 802. In illustration 1000, sheet 606 does not experience any visible springback after drill bit 622 drills through sheet 606. In another illustrative example, sheet 606 may experience visible springback after drill bit 622 drills through sheet 606.

[0095] 11, a cross-sectional view of an exemplary embodiment of a machining system is shown machining a sheet. In view 1100, the drill bit 622 is retracted from the sheet 606 in a first direction 902. A hole 1102 is drilled through the sheet 606. In view 1100, the compressive force 802 is maintained on the sheet 606. When the compressive force 802 is removed from the sheet 606, the tension on the sheet 606 is also released. As the compressive force 802 is removed from the sheet 606, springback occurs in a controlled manner. For example, at least one of the rate of springback and the timing of the onset of springback relative to the machining is controlled.

[0096] In some exemplary embodiments, the compressive force 802 acting on the sheet 606 is maintained while the rollers 625 and 627 roll across the surface 702 of the sheet 606. In these exemplary embodiments, the compressive force 802 is maintained while the end effector 612 moves relative to the sheet 606. In some of these exemplary embodiments, the compressive force 802 is maintained while the drill bit 622 machines the sheet 606 at multiple locations.

[0097] In another exemplary embodiment, the compressive force 802 is removed before the end effector 612 moves relative to the sheet 606. In some of these exemplary embodiments, the compressive force 802 is applied before the start of each machining run and removed after the start of each machining run.

[0098] Referring now to FIG. 12 , a perspective view of an exemplary embodiment of a machining system configured to reduce springback after machining is shown. The machining system 1200 is a physical implementation of the machining system 100 of FIG. 1 . The machining system 1200 is configured to reduce springback after machining. The machining system 1200 includes a number of linear force generators 1202, a number of load receivers 1204 connected to the number of linear force generators 1202, and a machining tool 1206 movable in a first direction parallel to the number of linear force generators 1202 independently of the number of linear force generators 1202. The number of load receivers 1204 are configured to apply a compressive force to define a compressive force region. The machining tool 1206 is positioned to perform machining within the region.

[0099] As shown, each of the number of load receivers 1204 is equidistant from the machining tool 1206. As shown, the number of load receivers 1204 includes pad 1208, pad 1210, and pad 1212. The number of force generators 1202 can take any form. In some illustrative examples, the number of linear force generators 1202 includes at least one of a number of springs or a number of pneumatic cylinders.

[0100] The machining tool 1206 is independently movable in a second direction perpendicular to the number of linear force generators 1202. As shown, the machining tool 1206 includes a drill bit 1214 having an axis 1216 that is parallel to the number of linear force generators 1202.

[0101] As shown, machining system 1200 takes the form of an end effector 1218. End effector 1218 is configured to reduce springback after machining.

[0102] The machining system 1200 includes a machining tool 1206 and a springback control system 1220. The springback control system 1220 includes a number of force generating devices 1222 and a number of load receivers 1204 connected to the number of force generating devices 1222. Each load receiver in the number of load receivers 1204 has a material contact surface. As shown, pad 1208 of the number of load receivers 1204 has a material contact surface 1224. Additionally, pad 1210 has a material contact surface 1226, and pad 1212 has a material contact surface 1228.

[0103] In the end effector 1218, each force-generating device of the number of force-generating devices 1222 is connected to a different one of the number of load-receiving members 1204. In the end effector 1218, each of the number of force-generating devices 1222 is connected to a pad 1208, pad 1210, or pad 1212 of a corresponding one of the load-receiving members.

[0104] In this exemplary embodiment, pads 1208, 1210, and 1212 are arranged to form a triangle. As can be seen from this exemplary embodiment, machining tool 1206 machines the workpiece in the triangular compressive force acting area formed by pads 1208, 1210, and 1212. As can be seen from this exemplary embodiment, machining tool 1206 is positioned between pads 1208, 1210, and 1212.

[0105] Pads 1208, 1210, and 1212 are placed in contact with the surface of the workpiece to reduce springback after machining with machining tool 1206. A predetermined number of force generating devices 1222 apply compressive forces to the workpiece, generating compressive forces. The machining is performed on the area with a machining tool 1206 while the sheet is under compressive force.

[0106] Reference is now made to FIG. 13, which is a flow chart illustrating a method for controlling springback in a sheet of material after machining using a machining system, according to an exemplary embodiment. Method 1300 may be performed using machining system 100 in manufacturing environment 102 of FIG. 1. Method 1300 may be performed using machining system 200 of FIGS. 2 and 3. Method 1300 may be performed using machining system 400 of FIGS. 4-5. Method 1300 may be performed using machining system 600 of FIGS. 6-11 in manufacturing environment 605. Method 1300 may be performed using machining system 1200 of FIG. 12.

[0107] Method 1300 includes applying a compressive force to the sheet using a number of force-generating devices connected to a number of load receivers in contact with a surface of the sheet to form a region of compressive force (operation 1302). Each load receiver in the number of load receivers has a material contact surface. The material contact surface takes the form of one of a movable surface or a fixed surface. If the material contact surface is a movable surface, the material contact surface may be, for example, a part of a roller. If the material contact surface is a fixed surface, the material contact surface may be, for example, a part of a pad.

[0108] The predetermined number of force generating devices can take any form, hi some exemplary embodiments, the predetermined number of force generating devices is a predetermined number of linear force generating devices.

[0109] The method 1300 includes completing a machining operation 1304 using a machining tool to complete a machining operation through the area of ​​the sheet surface while the sheet is under compressive force, which may be drilling, milling, countersinking, or any other desired machining operation, after which the method 1300 ends.

[0110] Completing the machining under compressive force can reduce or eliminate springback in the sheet after machining. Controlled springback occurs when the compressive force is removed from the sheet. Controlling the rate of springback and / or the timing of springback relative to the machining can improve the quality of the machining singularities and / or the life of the machining tools.

[0111] In some exemplary embodiments, a compressive force is applied to the sheet in the area prior to machining, which, in some exemplary embodiments, deflects the sheet to allow machining to occur in the desired location of the sheet.

[0112] In some exemplary embodiments, applying a compressive force to the region of the sheet includes moving a predetermined number of force-generating devices toward the surface of the sheet while keeping the predetermined number of load receivers in contact with the surface of the sheet, thereby compressing the predetermined number of force-generating devices (operation 1306). In some exemplary embodiments, method 1300 also includes moving a machining tool relative to the surface of the sheet while keeping the predetermined number of load receivers in contact with the surface of the sheet (operation 1308). In some exemplary embodiments, moving the machining tool relative to the surface of the sheet while keeping the predetermined number of load receivers in contact with the surface of the sheet is performed to perform a machining operation on a second location in the region. In some exemplary embodiments, moving the machining tool relative to the surface of the sheet while keeping the predetermined number of load receivers in contact with the surface of the sheet is performed when the machining operation is a countersink operation.

[0113] In some demonstrative embodiments, moving the machining tool relative to the surface of the sheet includes moving the machining tool relative to the surface while the machining is being performed (operation 1310).

[0114] In some demonstrative embodiments, method 1300 includes removing the machining tool from the sheet (operation 1312). Also, removing the compressive force from the sheet (operation 1314). After the machining tool and compressive force are removed from the sheet, the machining tool and the load receivers are moved relative to the surface of the sheet (operation 1316). A number of force-generating devices connected to a number of load receivers are used to apply compressive forces to a second portion of the sheet to form a second region of compressive force (operation 1318). With the compressive force applied to the second portion of the sheet, the machining tool is used to complete machining through the second region of the surface of the sheet (operation 1320).

[0115] Reference is now made to FIG. 14, which is a flow chart illustrating a method for reducing springback during machining in thin-walled sheets of material, according to an illustrative embodiment. Method 1400 may be performed using machining system 100 in manufacturing environment 102 of FIG. 1. Method 1400 may be performed using machining system 200 of FIGS. 2 and 3. Method 1400 may be performed using machining system 400 of FIGS. 4-5. Method 1400 may be performed in manufacturing environment 605 using machining system 600 of FIGS. 6-11. Method 1400 may be performed using machining system 1200 of FIG. 12.

[0116] In the method 1400, the thin sheet is deflected by an end effector toward a support tool (operation 1402). In the method 1400, machining is performed on the deflected thin sheet (operation 1404). Thereafter, the method ends.

[0117] In some example embodiments, the deflection of the thin-walled sheet is performed by a number of biasing devices attached to the same end effector that performs the machining (operation 1406). In some example embodiments, the number of biasing devices are part of a springback control system of the end effector.

[0118] In some example embodiments, deflecting the thin sheet includes deflecting the thin sheet a distance that is a function of a compressive force applied to the thin sheet by a predetermined number of load receivers (operation 1408), the compressive force being sufficient to temporarily deflect the thin sheet but less than to permanently deform the thin sheet.

[0119] In some demonstrative embodiments, performing the machining process includes further deflecting the thin sheet due to a processing force in the machining process, where the deflection due to the processing force is smaller than the deflection due to the compressive force of the predetermined number of load-bearing members (process 1410). When a hole is created in the thin sheet by the machining process and the processing force acting on the thin sheet is removed, springback occurs in the thin sheet, but the degree of springback is small because the thin sheet remains in a state deflected by the compressive force.

[0120] As used herein, the phrase "at least one," when used in conjunction with a list of items, means that one or more of the listed items can be used in various combinations, and that only one of each listed item may be required. In other words, "at least one" means that any number of the listed items may be used in any combination, but not all of the listed items are required. An item may be a particular object, thing, or category.

[0121] For example, "at least one of item A, item B, or item C" may include, but is not limited to, item A, or item A and item B, or item B. This example may further include item A, item B, and item C, or item B and item C. Of course, any combination of these items is possible. In another example, "at least one" may include, but is not limited to, two item A, one item B, and ten item C, or four item B and seven item C, or any other suitable combination.

[0122] The flowcharts and block diagrams in the various illustrated embodiments illustrate the architecture, functionality, and processes of some aspects in which the apparatus and methods of the example embodiments may be implemented. In this regard, each block in the flowcharts or block diagrams may represent a module, a segment, a function, and / or a portion of a process or step.

[0123] In alternative aspects of an exemplary embodiment, one or more functions noted in a block may be performed in a different order than shown. For example, in some cases, two blocks shown in succession may be performed substantially concurrently, or may sometimes be performed in the reverse order, depending on the functionality involved. Also, additional blocks may be added to blocks depicted in a flowchart or block diagram. Some blocks may be optional. For example, in method 1300, operations 1308-1322 may be optional. As another example, in method 1400, operations 1406-1410 may be optional.

[0124] An exemplary embodiment of the present disclosure may be described with respect to aircraft manufacturing and service method 1500 shown in Figure 15 and aircraft 1600 shown in Figure 16. Referring first to Figure 15, a block diagram of an aircraft manufacturing and service method is shown in Figure 15, in accordance with an exemplary embodiment. During pre-production, aircraft manufacturing and service method 1500 includes specification and design 1502 and material procurement 1504 of aircraft 1600 shown in Figure 16.

[0125] During production, the manufacture 1506 of parts and subassemblies of the aircraft 1600, as well as and system integration 1508. The aircraft 1600 then undergoes certification and delivery 1510 and enters service 1512. While in customer service 1512, the aircraft 1600 is scheduled for routine maintenance and service 1514, which may include modifications, reconfigurations, refurbishments, or other maintenance and service.

[0126] Each step of aircraft manufacturing and service method 1500 may 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 purposes of illustration, a system integrator may include, but is not limited to, any number of aircraft manufacturers and major system subcontractors. A third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers. An operator may be an airline, a leasing company, a military entity, a service organization, etc.

[0127] Referring now to Figure 16, a block diagram of an aircraft is shown in which illustrative embodiments may be implemented. In this example, aircraft 1600 is produced according to aircraft manufacturing and service method 1500 shown in Figure 15 and includes an airframe 1602 with a number of systems 1604 and an interior 1606. Examples of systems 1604 include one or more of a drive train 1608, an electrical system 1610, a hydraulic system 1612, and an environmental system 1614, as well as any number of other systems. Additionally, while an aerospace application is shown as an example, various illustrative embodiments may be applied to other industries, such as the automotive industry.

[0128] Apparatus and methods embodied herein may be employed during at least one stage of aircraft manufacturing and service method 1500. One or more illustrative embodiments may be employed during part and subassembly manufacturing 1506, system integration 1508, or maintenance and service 1514, as shown in FIG. 15 . For example, machining system 100 with springback control system 106 may be used to fabricate part 162 during part and subassembly manufacturing 1506. In another illustrative embodiment, machining system 100 with springback control system 106 may be used to fabricate replacement parts during maintenance and service 1514. Machining system 100 may be used to fabricate a portion of aircraft 1600, such as fuselage 1602, or a portion of interior 1606.

[0129] Exemplary embodiments provide a machining system and method configured to reduce springback after machining. Exemplary embodiments provide a springback control system configured to apply a compressive force to a sheet. Applying a compressive force to the sheet creates a compressive force area. Machining the compressive force area can reduce or eliminate springback after machining is complete. Reducing or eliminating springback can improve the quality of machined areas, such as holes or slots. Reducing or eliminating springback can reduce risk to machining tools.

[0130] Incorporating a springback control system into a machining system can reduce at least one of the complexity, time, and cost of securing a sheet to a support tool. For example, using a springback control system to apply a compressive force to the sheet can eliminate the need to use adhesive to secure the sheet to the support tool. In another example, using a springback control system to apply a compressive force to the sheet can eliminate the need to add mechanical or vacuum components to the support tool.

[0131] In some exemplary embodiments, a predetermined number of biasing devices apply a load to the thin sheet. By applying the load to the thin sheet, the thin sheet reversibly deflects toward the support tool. Machining of the thin sheet is completed with the thin sheet under the load. In some exemplary embodiments, the load is applied to the thin sheet before machining. By deflecting the sheet before machining, machining singularities can be formed at desired locations. By deflecting the sheet before completing machining, machining springback can be reduced.

[0132] The present disclosure further includes examples according to the following appendices:

[0133] Appendix 1. A method for controlling springback of a sheet of material after machining using a machining system, the method comprising: applying a compressive force to the sheet using a number of force generating devices connected to a number of load receiving members in contact with a surface of the sheet to form a region of compressive force; and completing machining through the region of the surface of the sheet with a machining tool while the sheet is under the compressive force.

[0134] Clause 2. The method of clause 1, further comprising moving the machining tool relative to the surface of the sheet while keeping the predetermined number of load bearing members in contact with the surface of the sheet.

[0135] Appendix 3. The method of Appendix 2, wherein moving the machining tool relative to the surface of the sheet includes moving the machining tool relative to the surface while performing the machining.

[0136] Appendix 4. The method of any one of Appendixes 1-3, further comprising: removing the machining tool from the sheet; removing the compressive force from the sheet; moving the machining tool and the load receiving member relative to the surface of the sheet after removing the machining tool and the compressive force from the sheet; applying a compressive force to a second portion of the sheet using the predetermined number of force generating devices connected to the predetermined number of load receiving members to form a second area where a compressive force acts; and completing machining through the second area of ​​the surface of the sheet using the machining tool while applying the compressive force to the second portion of the sheet.

[0137] Appendix 5. The method of any one of Appendixes 1 to 4, wherein applying the compressive force to the region of the sheet includes moving the predetermined number of force generating devices toward the surface of the sheet while the predetermined number of load receiving members are in contact with the surface of the sheet, thereby compressing the predetermined number of force generating devices.

[0138] Appendix 6. A machining system configured to reduce springback after machining, comprising: a machining tool; and a springback control system including a predetermined number of force generating devices and a predetermined number of load receiving members connected to the predetermined number of force generating devices, wherein each load receiving member in the predetermined number of load receiving members has a material contact surface.

[0139] Clause 7. The machining system of clause 6, wherein each load receiver in the predetermined number of load receivers is associated with a corresponding force generating device in the predetermined number of force generating devices.

[0140] Appendix 8. The machining system of Appendix 6, wherein a plurality of force generating devices in the predetermined number of force generating devices are associated with one load receiving member among the predetermined number of load receiving members.

[0141] Appendix 9. The machining system of any one of appendices 6 to 8, wherein the machining tool is movable independently of the springback control system.

[0142] Appendix 10. The machining system of any one of appendices 6 to 9, wherein each of the predetermined number of load-receiving members further includes a linear bearing and a carriage.

[0143] Appendix 11. The machining system of any one of Appendixes 6 to 10, wherein each material contact surface is one of a roller or a pad.

[0144] Appendix 12. The machining system of any one of Appendixes 6 to 11, wherein the machining tool includes a drill bit.

[0145] Appendix 13. The machining system of Appendix 6, wherein the number of force generating devices includes a number of linear force generating devices, the number of load receiving members are connected to the number of linear force generating devices and configured to apply a compressive force to define a region on which the compressive force acts, and the machining tool is movable independently of the number of linear force generating devices.

[0146] Appendix 14. A machining system configured to reduce springback after machining, comprising: a predetermined number of linear force generators; a predetermined number of load-receiving members connected to the predetermined number of linear force generators and configured to apply a compressive force to form an area on which the compressive force acts; and a machining tool movable independently of the predetermined number of linear force generators.

[0147] Addendum 15. The machining system of Addendum 13 or 14, wherein the machining tool is movable in a first direction parallel to the predetermined number of linear force generators independently of the predetermined number of linear force generators, and the machining tool is positioned to perform machining within the area.

[0148] Appendix 16. The machining system according to any one of appendices 13 to 15, wherein each of the predetermined number of load-receiving members is equidistant from the machining tool.

[0149] Appendix 17. The machining system of any one of Appendixes 13 to 16, wherein the predetermined number of load-receiving members include pads configured to form a working area for the machining tool.

[0150] Appendix 18. The machining system of any one of Appendixes 13 to 17, wherein the predetermined number of load-receiving members includes at least one of a predetermined number of rollers or a predetermined number of pads.

[0151] Appendix 19. The machining system of any one of Appendixes 13 to 18, wherein the predetermined number of linear force generating devices include at least one of a predetermined number of springs or a predetermined number of pneumatic cylinders.

[0152] Appendix 20. The machining system of any one of Appendixes 13 to 19, wherein the machining tool is independently movable in a second direction perpendicular to the predetermined number of linear force generating devices.

[0153] Addendum 21. A machining system according to any one of Addendums 13 to 20, wherein the machining tool includes a drill bit having an axis parallel to the predetermined number of linear force generators.

[0154] Appendix 22. A method for reducing springback of a thin-walled sheet during machining, the method comprising: deflecting the thin-walled sheet toward a support tool with an end effector; and machining the thin-walled sheet while the thin-walled sheet is in the deflected state.

[0155] 23. The method of claim 22, wherein the deflection of the thin-walled sheet is performed by a number of biasing devices attached to the same end effector that performs the machining.

[0156] Clause 24. The method of clause 22 or 23, wherein deflecting the thin-walled sheet includes deflecting the thin-walled sheet a distance that is a function of compressive forces applied to the thin-walled sheet by a predetermined number of load-bearing members.

[0157] Addendum 25. The method of any one of Addendums 22 to 24, wherein the bending of the thin sheet is performed by a predetermined number of biasing devices, and the machining includes further bending the thin sheet by a processing force in the machining, and the bending due to the processing force is smaller than the bending due to the compressive force of the predetermined number of biasing devices.

[0158] While various exemplary embodiments have been described, this description is for purposes of illustration and description and is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Various modifications and variations will be apparent to those skilled in the art. Furthermore, different exemplary embodiments may provide different features than other exemplary embodiments. The embodiments described herein have been selected to best explain the principles and practical applications of the embodiments, and to enable those skilled in the art to appreciate various embodiments with various modifications to adapt the present disclosure to particular applications.

Claims

1. 1. A method for controlling springback of a sheet of material after machining with a machining system, comprising: applying a compressive force to the sheet using a number of force generating devices connected to a number of load receivers in contact with a surface of the sheet to form a compressive force region; and completing machining through said area of ​​said surface of said sheet with a machining tool while applying said compressive force to said sheet.

2. The method of claim 1 , further comprising moving the machining tool relative to the surface of the sheet while keeping the predetermined number of load bearing members in contact with the surface of the sheet.

3. The method of claim 2 , wherein moving the machining tool relative to the surface of the sheet comprises moving the machining tool relative to the surface while performing the machining.

4. removing the machining tool from the sheet; removing the compressive force from the sheet; and removing the machining tool and the compressive force from the sheet, and then moving the machining tool and the load-receiving member relative to the surface of the sheet; applying a compressive force to a second portion of the sheet using the number of force generating devices connected to the number of load receivers to form a second region of compressive force; completing machining through the second area of ​​the surface of the sheet with the machining tool while applying the compressive force to the second portion of the sheet; The method of any one of claims 1 to 3, further comprising:

5. 5. The method of claim 1, wherein applying the compressive force to the region of the sheet comprises moving the predetermined number of force generating devices toward the surface of the sheet while the predetermined number of load receiving members are in contact with the surface of the sheet, thereby compressing the predetermined number of force generating devices.

6. 1. A machining system configured to reduce springback after machining, comprising: Machining tools; 1. A machining system comprising: a springback control system including a number of force generating devices; and a number of load receiving members connected to the number of force generating devices, wherein each load receiving member in the number of load receiving members has a material contact surface.

7. 7. The machining system of claim 6, wherein each load receiver in said predetermined number of load receivers is associated with a corresponding one of said predetermined number of force generating devices.

8. The machining system of claim 6 , wherein a plurality of force generating devices in the predetermined number of force generating devices are associated with one load receiving member of the predetermined number of load receiving members.

9. The machining system according to any one of claims 6 to 8, wherein the machining tool is movable independently of the springback control system.

10. the predetermined number of force generating devices includes a predetermined number of linear force generating devices; The predetermined number of load receiving members are connected to the device and , configured to apply a compressive force to form a region on which the compressive force acts; The machining system of claim 6 , wherein the machining tool is movable independently of the number of linear force generating devices.

11. the machining tool is movable in a first direction parallel to the number of linear force generators independently of the number of linear force generators, and the machining tool is positioned to perform machining within the area; The machining system of claim 10 , wherein the machining tools are independently movable in a second direction perpendicular to the number of linear force producing devices.

12. 12. The machining system of claim 10 or 11, wherein the predetermined number of load bearing members comprises pads configured to form a working volume for the machining tool.

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