1. Field
The present disclosure generally relates to fabrication of laminates, especially those that are contoured, and deals more particularly with a method and apparatus for automated layup and forming of different laminate structures within a family of structures having common features.
2. Background
Composite structures, especially those having contours, sometimes have features that require that the structure be formed of multiple parts. For example, in the aircraft industry, contoured composite fuselage barrel frame sections may be formed using a two-piece assembly comprising a channel section frame and a shear tie, mechanically fastened together. More recently, one-piece composite frame sections have been proposed that employ braided composites, however this fabrication approach is time consuming and labor intensive, and may result in a frame that is heavier than desired. The problem of fabricating one-piece frame sections is more difficult in high production rate environments where production flow times may be important to achieve manufacturing efficiencies.
Accordingly, there is a need for a method and apparatus for producing one-piece laminate structures, especially those that are contoured, which reduce labor and assembly time through automation. There is also a need for a method and apparatus for producing different laminate structures within a family of structures having common features in order to reduce material and labor costs while increasing production rates. Furthermore, there is a need for a method and apparatus for fabricating laminate structures using certain material forms such as unidirectional pre-preg tape, that may not be producible using conventional, manual fabrication methods.
The disclosed embodiments provide a method and apparatus for producing different composite laminate structures within a family of structures having common features. The apparatus comprises an automated, reconfigurable composite forming system especially designed to form unidirectional pre-preg tape in the production of structural members, such as aircraft fuselage frames. The apparatus comprises a plurality of substantially identical forming modules linked together to form a single former that may be reconfigured to conform to a wide range of tools defining corresponding structural shapes. Each of the forming modules possesses the ability to locally adapt or transform to the unique design, shape or features of the tool. In one aircraft application, the apparatus may be employed to fabricate multi-ply composite frame sections having a Z cross-sectional shape, by laying up, forming and compacting each ply of the frame section. The plies are formed from an inner chord outwardly to an outer chord, sometimes referred to as a shear tie. Each of the forming modules adapts to the local shape of the tool. The modules are linked together in a manner to form a single former that adjusts to the entire tool. Different tool arc lengths can be accommodated by adding or removing forming modules. It is not necessary that the forming modules exactly match the total arc length of a tool in those cases where the structure is contoured. The apparatus employs an adaptive control system based on a generic structural shape profile of structures within a family of structures. The adaptive control system forms each ply of the structure based on a combination of force feedback and positional control. Each forming module has two servo axes and employs force feedback on one of these two axes at a time. The use of force feedback is dependent upon the area of the structure being formed. During the forming process, the feedback switches back and forth between the two axes. Switching between the two axes is controlled by the adaptive system and is determined by generic shape parameters of the structure being formed. Reliance on a generic motion profile allows the apparatus to form any of a multiplicity of unique structures, ply-by-ply without the need for NC (numerical control) programming. The apparatus is easily scalable to fabricate structures of different sizes within a family of structures by adding or removing forming modules, and arranging the modules to substantially match corresponding tool shapes.
According to one disclosed embodiment, a system is provided for fabricating a plurality of unique parts. The system comprises a plurality of unique lay-up tools respectively corresponding to the plurality of parts to be fabricated and, a plurality of former modules configured to be combined together to define a plurality of unique formers respectively corresponding to the plurality of parts and the plurality of lay-up tools. Each of the formers is adapted for laying down material on a corresponding one of the lay-up tools to form a corresponding one of the parts. The former modules are substantially identical, and each of the plurality of unique formers is configured by coupling each of the substantially identical former modules to the corresponding unique lay-up tool. The former modules are linked together and are mounted on bases allowing the former modules to move in multiple directions. Each of the former modules includes a forming head adapted to form the material on a corresponding one of the lay-up tools. Each of the forming heads includes compliance. The part may be a laminated structure, and the laminated structure may be a carbon fiber reinforced plastic.
According to another disclosed embodiment, apparatus is provided for fabricating each of a plurality of differing laminate structures in a family of structures having common features. The apparatus comprises a plurality of separate fabrication modules each locally adapted to fabricate a section of the laminate structure on a corresponding tool. The fabrication modules are reconfigurable to fabricate each of the laminate structures in the family thereof. The apparatus also includes a controller for controlling and coordinating automated operation of the fabrication modules. The apparatus may further comprise a forming member adapted for forming laminate plies over the tool. The forming member extends along a length of the fabrication modules, and is mounted on each of the fabrication modules for movement over the tool along at least two axes. The forming member is continuous along the length of the fabrication modules. The forming member is controlled along two axes, but has a shape that adapts to changes between different areas of the structure being formed, such as, in the case of a one-piece aircraft fuselage frame, between an inner chord radius and a shear tie radius of the frame. Each of the fabrication modules includes a track in which a portion of the forming member is locally mounted. A single forming member may be used to fabricate a particular structure, however the forming member is removably mounted in the track to allow interchangeability of a plurality of forming members respectively having different shapes to fabricate differently shaped structures. The track allows for lateral (or tangential) slip of the forming member relative to each module as the arc length of the structure changes as the forming member moves over the structure. The forming member is adapted to sweep laminate plies over the tool, and includes compliance. Each of the fabrication modules includes a clamp adapted for clamping a portion of a laminate ply against a portion of the tool. Each of the fabrication modules includes a powered drive coupled with the forming member for sweeping the forming member over the laminate plies and compacting laminate plies on the tool. The apparatus may further comprise a flexible ply carrier adapted to hold at least one laminate ply thereon, wherein each of the fabrication modules includes a pair of spaced apart tracks adapted to releasably hold the ply carrier, and a ply carrier control assembly for holding the ply carrier in tension as the forming member forms the ply over the tool. The forming member is engageable with the ply carrier to sweep the ply carrier along with the ply thereon over the tool, and the ply carrier control assembly includes drives for adjusting the position ply carrier along two axes. Each of the fabrication modules further includes a force sensor for sensing a level of force applied to the laminate plies by the forming member, and a position sensor for sensing the position of the forming member. Each of the fabrication modules further includes a clamp for clamping the fabrication module to the tool. The apparatus may also comprise linkage between the fabrication modules for coupling the fabrication modules together and for aligning the fabrication modules relative to the tool. The linkage is configured to allow the forming modules to rotate along an arc that is substantially the same as the retracted arc of the continuously extending forming member. The fabrication modules are substantially identical and interchangeable with each other. The apparatus also includes a central controller for controlling and coordinating the operation of the fabrication modules to collectively fabricate the laminate structure.
According to still another embodiment, a method is provided of fabricating a plurality of differing parts in a family of parts having common features, wherein each of the parts is fabricated using a unique tool. The method comprises arranging a plurality of separate, substantially identical fabrication modules to substantially match a tool on which one of the parts is to be fabricated, and adapting each of the fabrication modules to a local section of the tool. The method further comprises controlling and coordinating operation of the fabrication modules to fabricate portions of the part over a corresponding section of the tool. Arranging the fabrication modules includes moving each of the fabrication modules into proximity to the tool, and linking the fabrication modules together. The method may further comprise clamping each of the fabrication modules to the tool. Adapting each of the fabrication modules includes learning, by each of the fabrication modules, the location of surfaces on the tool on which the part is to be fabricated. The method may also comprise sweeping materials across the surfaces of the tool using a forming member, and using the forming member to learn the location of the surfaces on the tool. Learning the location of the surfaces includes sensing the position of the forming member as the forming member sweeps materials across the surfaces of the tool, and recording the sensed position of the forming member. Adapting each of the fabrication modules includes adjusting the elevation of the fabrication modules to a common waterline. The method may further comprise forming a continuous spline along all of the fabrication modules. Forming the continuous spline includes mounting a continuous forming member along substantially the entire length of the fabrication modules. Each of the fabrication modules may be a laminate ply former module for forming a local section of a ply. Arranging the fabrication modules includes linking the fabrication modules together to form a single laminate ply former.
According to another disclosed embodiment, a method is provided of fabricating a composite laminate structure. The method comprises arranging a plurality of substantially identical forming modules to generally match a tool on which composite plies are to be formed to fabricate the laminate structure, and linking the forming modules together to form a single former for forming an entire composite laminate structure. The method further comprises mounting a continuous forming member on the forming modules, the continuous forming member defining a spline extending substantially the entire length of the former, and using the forming member to form and compact the composite plies on the tool. The method may also include placing the composite plies on a ply carrier. The forming member is used to engage and sweep the ply carrier along with the plies over the tool.
According to still another disclosed embodiment, a forming module is provided for forming a composite laminate part over a tool. The forming module comprises a base and a ply carrier control assembly adapted for controlling the position of a flexible ply carrier on which composite resin plies are mounted. The forming module further comprises a head section mounted on the base and adapted for automatically forming the composite resin plies from the ply carrier onto the tool. The base is adapted to move over a supporting surface, and the head section includes adaptive control for learning a profile of the tool. The forming module may further include a clamp for clamping the head section to the tool, and an automatically controlled forming member for forming the plies over the tool.
The features, functions, and advantages can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments in which further details can be seen with reference to the following description and drawings.
The novel features believed characteristic of the illustrative embodiments are set forth in the appended claims. The illustrative embodiments, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment of the present disclosure when read in conjunction with the accompanying drawings, wherein:
Referring first to
Attention is now directed to
As previously mentioned, the former 40 may be used to form a variety of composite parts within a family of parts having common features or characteristics. For example, referring to
Referring now to
Attention is now directed to
The ply carrier control assembly 86 controls the attitude of, and tension on the ply carrier 84 in order to support and continuously reposition position the ply 46 as it is being formed onto the tool 48. The ply carrier control assembly 86 may include a motorized drive system which moves the support arm 95 and thus the carrier support track 120 along both the Y and Z axes. For example, the motorized drive system may comprise a servo-motor 88 for driving the carrier support track 120 along the Y axis, and an air cylinder 90 for driving the support arm 95 and the carrier support track 120 along the Z axis. Other drive arrangements are possible.
The head section 92 includes a ply forming member, referred to hereinafter as a nosepiece 116, which engages the ply carrier 84 and follows the shape of the tool 48 to form and compact the ply 46 onto the tool 48. The nosepiece 116 is removably mounted in a nosepiece track 118 discussed later in more detail. The nosepiece 116 extends continuously along the entire arc length of the tool 48, and effectively forms a spline between the forming modules 42. Both the nosepiece 116 and the track 118 may be flexible along their length to conform to the curvature and other features of the tool 48. The nosepiece track 118 is coupled with a motorized drive system which may comprise, for example and without limitation, a plurality of air cylinders 102 which move the nosepiece 116 in the Y direction.
Movement of the nosepiece 116 in the Z direction may be effected through movement of the head section 92 by the Z-axis slide assembly 108 on the base 106. The head section 92 further includes an inner chord clamp 122 driven in the Y direction by air cylinders 104 or similar motor drives. The inner chord clamp 122 clamps the lower edge of the ply carrier 84 and the ply 46 against the inner chord tool flange 72 (
As can be appreciated from the foregoing description, the former 40 provides 2-axis (Y-Z) controlled sweeping of pre-preg plies with 2-axis coordinated motion. However, motion is not limited to 2 axes. For example, the required motion may be accomplished using multiple robots (not shown) operating in unison. The adaptive control employed by former 40 allows the former 42 to adapt to each particular tool 48 used to make any of a number of parts within a family of parts, by using a generic profile of the parts in the family, and force feedback to learn and follow the specific tool and part geometry. The adaptive control used by the former 40 also automatically adapts or adjusts to the shape of the part 54 as the thickness of the part 54 increases with layup of each successive ply 46. The use of a combination of position control and motor torque feedback allow constant pressure to be applied by the nosepiece 116 to the part 54 during the forming process.
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Referring to
Attention is now directed to
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At 196, the transition of the nosepiece 116 from the inner chord tool surface 72 to the web tool surface 76 is sensed by monitoring a Y-axis encoder 96 for a change. At 198 control of the nosepiece 116 along the Y-axis is switched from a torque mode to a position mode, and along the Z-axis from a position mode to a torque mode. The nosepiece 116 maintains compaction pressure against the ply 46 during the transition over the inside corner 74 of the inner chord to web radius. At 200, the nosepiece 116 sweeps and compacts the ply against the web tool surface 76 on the tool 48. At 202, movement of the nosepiece 116 is terminated when the nosepiece 116 is a short distance from the shear tie radius 78. At 204, the nosepiece 116 is used to “discover” the shape of the shear tie radius 78. This is accomplished by advancing the nosepiece 116 along the Y-axis until a preselected torque limit is reached. At step 206, control of the nosepiece 116 is switched to the torque mode along the Y-axis and along the Z-axis. At 208, the nosepiece 116 sweeps and compacts apply against the shear tie tool surface 80. During this step, the nosepiece 116 applies force along the Y-axis in the torque mode, while being driven upwardly along the Z-axis in the position mode. At step 210 the ply forming process is complete and steps 182-208 may be repeated to layup, form and compact additional plies.
Embodiments of the disclosure may find use in a variety of potential applications, particularly in the transportation industry, including for example, aerospace, marine, automotive applications and other application requiring automated fabrication of a variety of parts within a family of parts having common features or characteristics. Thus, referring now to
Each of the processes of method 212 may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., 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, leasing company, military entity, service organization, and so on.
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Systems and methods embodied herein may be employed during any one or more of the stages of the production and service method 212. For example, components or subassemblies corresponding to production process 220 may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft 214 is in service. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during the production stages 220 and 222, for example, by substantially expediting assembly of or reducing the cost of an aircraft 214. Similarly, one or more of apparatus embodiments, method embodiments, or a combination thereof may be utilized while the aircraft 242 is in service, for example and without limitation, to maintenance and service 228.
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 advantages 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.
This application claims the benefit of Provisional U.S. Patent Application No. 61/749,881 filed Jan. 7, 2013, which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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61749881 | Jan 2013 | US |