Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of and claims priority to U.S. application Ser. No. 11/116,222 filed on Apr. 28, 2005 and entitled MACHINE ASSISTED LAMINATOR AND METHOD, the entire contents of which is expressly incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure generally relates to a ply placement device. More particularly, the present disclosure pertains to a device for and method of placing plies on a surface. 
     BACKGROUND 
     Composite items are generally constructed from layers of material that are laminated together. These layers are often referred to as partial or full plies. For structures exceeding the available material width, each layer is typically made up of a series of strips or courses of material placed edge to edge next to each other or are overlapped to some extent. Each ply may be in the form of woven fibers in a fabric, unidirectional fiber material, metal foils, adhesive films or a variety of other conformations. Unidirectional fiber material is often termed, “tape.” The fibers may be made from any of a multitude of natural and/or “man-made” materials such as fiberglass, graphite, Kevlar®, and the like. 
     The courses are generally laid upon the form or tool along a “natural path” of the course material. The term “natural path” refers to the path the course material would follow when rolled out on to the surface of the tool. Deviations from the natural path are generally achieved by applying force across the width of the course material. Tape is typically more rigid than fabric and tends to resist this force to a greater extent. When the force applied exceeds the flexing capacity of the material, wrinkles or bridges form in the course material. In addition, the wider the course is, the more prone the course material is to wrinkle. 
     Tape courses are typically applied edge to edge. To reduce internal voids, it is generally advantageous to reduce the gap distance or tolerance between the tape courses. For example, in certain relatively high technology industries such as the aerospace industry, the gap distance may be held to 0.10″ or less. For flat or cylindrical composite items, the natural path of each course is in alignment with adjacent courses. However, for contoured items, the natural path of adjacent courses may tend to cause the courses to converge or diverge. To prevent these deviations from causing the courses to overlap or diverge in excess of the tolerance, conventional automated tape lamination machines (“ATLM”) generally utilize a relatively greater number of a relatively narrower course material. Unfortunately, utilizing narrower course material reduces lay-down rates. 
     Accordingly, it is desirable to provide a method and apparatus capable of overcoming the disadvantages described herein at least to some extent. 
     SUMMARY 
     The foregoing needs are met, to a great extent, by the present disclosure, wherein in one respect an apparatus and method is provided that in some embodiments accurately place plies on a substrate. 
     An embodiment of the present disclosure relates to a system to fabricate a composite item. This system includes an end effector, robotic vehicle, sensor, and cutting system. The end effector applies a course to a layup form. The robotic vehicle positions the end effector. The sensor senses an edge of a previously applied course. The cutting system cuts a profile on the course in response to the sensed edge. 
     Another embodiment of the present disclosure pertains to an apparatus to fabricate a composite item. This apparatus includes a means for generating, means for advancing, means for sensing, and means for cutting. The means for generating generates a partial vacuum between a ply material and a layup form. The means for advancing advances the partial vacuum and the ply material along the layup form. The means for sensing senses an edge of a previously applied course of the ply material. The means for cutting cuts a profile on the ply material in response to the sensed edge. 
     Yet another embodiment of the present disclosure relates to a method of fabricating a composite item. In this method, a partial vacuum is generated between a ply material and a layup form and the partial vacuum and the ply material are advanced along the layup form. In addition, an edge of a previously applied course of the ply material is sensed and a profile is cut on the ply material in response to the sensed edge. 
     There has thus been outlined, rather broadly, certain embodiments of the disclosure in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the disclosure that will be described below and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the disclosure in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The disclosure is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present disclosure. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an automated tape lamination machine according to an embodiment of the disclosure. 
         FIG. 2  is a perspective view of a front of an end effector suitable for use with the automated tape lamination machine of  FIG. 1 . 
         FIG. 3  is a perspective view of a rear of an end effector suitable for use with the automated tape lamination machine of  FIG. 1 . 
         FIG. 4  is an exploded view of a ply layup according to an embodiment of the disclosure. 
         FIG. 5  is a block diagram of a system architecture for an automated tape lamination system in accordance with an embodiment of the disclosure. 
         FIG. 6  is a block diagram of a system architecture for a controller suitable for use in the system according to  FIG. 5 . 
         FIG. 7  is a flow diagram illustrating steps of a method in accordance with an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. As shown in  FIG. 1 , a machine assisted laminator  10  (“MAL”) suitable for use in an embodiment of the disclosure includes one or more robotic vehicles  12  to position a ply material  14  upon a form  16  to generate an item  18 . The robotic vehicles  12  are guided by a guidance system  20 . The guidance system  20  includes one or more laser emitters  22 , laser receivers  24 , and a control unit  26 . The control unit  26  is configured to receive instructions from a user and forward instructions to the laser emitters  22 . The laser emitters  22  are configured to forward signals, via laser, to the laser receivers  24  and thereby control the movement of the robotic vehicles  12 . In this manner, a set of computer readable instructions are utilized by the MAL  10  to fabricate the item  18 . A more detailed description of the robotic vehicles  12  and the guidance system therefore are to be found in U.S. patent application Ser. No. 10/986,292, entitled, OPTICAL LASER GUIDANCE SYSTEM APPARATUS AND METHOD, filed on Nov. 12, 2004, by Roger J. LEDET and John E. YESTRAU, the disclosure of which is hereby incorporated in its entirety. 
     In an embodiment, the MAL  10  includes two or more robotic vehicles  12  configured to co-operatively apply the ply material  14  to the form  16 . For example, as shown in  FIG. 1 , each robotic vehicle  12  initiates placement of the ply material  14  at or near a center portion of the form  16  and then co-operatively work outward and to different portions of the form  16 . Thus, it is an advantage of embodiments of the disclosure that material lay down rates are increased over ATLMs that have only one conventional end effector. In another example, the robotic vehicles  12  are configured to co-operatively weave two or more layers of the ply material  14  together upon the form  16 . Thus, it is an advantage of embodiments of the disclosure that structural integrity of the item  18  is increased and de-lamination of the item  18  is decreased by weaving multiple layers of the ply material  14  together. 
     In another embodiment of the disclosure, the MAL  10  includes a robotic armature or gantry-type positioning device configured to position or otherwise control the placement of the ply material upon the form  16 . In a particular example, the gantry-type positioning device is configured to control ten axes of movement (five axes of the gantry and five axes of an end effector). However, it is to be understood that the specific number of axes may depend upon the particular operating condition and thus, the number of axes controlled is not critical to the disclosure. In yet other embodiments, the set of computer readable instructions are utilized to control the movements of the tool  16 . For example, the tool  16  includes a rotating mandrel or X-Y table. 
     Each robotic vehicle  12  is configured to apply course material  14  on the form  16 . In various forms, the robotic vehicles  12  include a compaction roller, sweep, and/or vacuum placement shoe to apply the course material  14  to the form  16 . The form  16  is configured to provide a suitably stable and finished surface for ply placement. Characteristics of the form  16 , such as size, shape, contour, and the like, are based upon design parameters of an item  18 . The item  18  is shown in  FIG. 1  being constructed from a plurality of courses  28 . Each layer of the courses  28  placed upon the form  16  or a substrate  30  is described as a ply and the item  18  is typically fabricated from a plurality of plies. The substrate  30  includes the form  16  surface and/or a previously applied course  28 . 
       FIG. 2  is a perspective view of a front of an end effector  32  that is suitable for use with the MAL  10 . The end effector  32  is positioned by the robotic vehicle  12  or any suitable positioning device such as, for example, a robotic armature, gantry type device, and the like. As shown in  FIG. 2 , the end effector  32  includes a supply roll  34  to dispense a course material  14 . This supply roll  34  is supported by a support  36 . In a particular embodiment, the support  36  includes a pair of rollers to facilitate rolling of the supply roll  34 . In this manner, the course material  14  is withdrawn from the supply roll  34 . Specifically, the rollers facilitate an unpowered or “free wheeled” removal of the course material  14  from the supply roll  34 . That is, the course material  14  is drawn off the supply roll  34  via the movement of the end effector  32  without need of relatively complex servo motors and control systems. Thus, simplifying and improving the reliability. 
     The course material  14  includes any suitable course material. Examples of suitable course material include various fibers, films, foils, and/or the like. Particular examples of fibers include glass, aramid, carbon, and various other fibers in the form of unidirectional “tape,” woven fabric, biaxial cloth and the like. In addition, the course material  14  may be pre-impregnated with a resin or other such binding substance. The course material  14  optionally includes a backing or separator film  40  (Shown in  FIG. 4 ) to substantially prevent the course material  14  from adhering to itself while in roll form. 
     The end effector  32  further includes a sensor  38 . The sensor  38  includes any suitable sensing device. Examples of suitable sensing devices include tactile, optical, and systems employing various forms of electromagnetic radiation such as infra red (IR), microwave, and the like. In a particular example and as discussed further herein, the sensor  38  includes a machine vision system configured to determine the position of an edge  42  of a previously applied course  28 . In various other examples, the sensor  38  includes an array of feelers that contact the substrate  30  and sense a difference in height and/or an array of photo detectors that sense differences in incident light reflected from the substrate  30 . 
     The MAL  10  typically applies the course material  14  upon the substrate  30  along a “natural path.” Generally, the natural path is described in terms of a path the course material  14  would take when rolled out upon the substrate  30 . More specifically, a centerline  44  of the natural path is described geometrically as a geodesic curve on the substrate  30 . That is, the shortest distance between two points that lies on the substrate  30 . 
       FIG. 2  additionally illustrates an interface  46  disposed between two adjoining courses  28 . This interface  46  generally coincides with the warp direction of the flanking courses  28 . The interface  46  may diverge somewhat from the warp direction of one or both of the flanking courses  28  depending upon the taper or profile of the courses  28 . The item  18  typically includes multiple plies and it is not uncommon that two or more plies may lay in the same or approximately same warp direction. Plies laying in the same warp direction are generally separated by several plies in other warp directions. Still, it is preferable that interfaces  46  of the plies laying in the same or similar warp direction are not in alignment. It is an advantage of an embodiment that the alignment of the interfaces  46  are determined and adjusted or offset if found to be in alignment. 
       FIG. 3  is a perspective view of a rear of the end effector  32  suitable for use with the MAL  10 . As shown in  FIG. 3 , the end effector  32  further includes a cutting assembly  48  configured to cut the course material  14 . In general, the cutting assembly  48  performs cuts to generate a side edge profile. In addition, the cutting assembly performs end cuts, such as leading edge and trailing edge cuts. The cutting assembly  48  includes any suitable cutting device  50  operable to sever or otherwise cut the course material  14 . Suitable devices include ultrasonic knives, saws, lasers, and the like. Furthermore, the cutting assembly  48  includes an actuator  52  to position the cutting device  50  along a rail  54  that traverses the course material  14 . The actuator  52  is configured to respond to signals from a controlling device. 
     In operation, the MAL  10  is configured to apply the courses  28  to generate a ply of the item  18 . The course material  14 , is typically applied according to the manufacturer&#39;s specifications. For example, courses of unidirectional tape are typically abutted and/or applied within a gap tolerance of about 0.10 inches with essentially no overlap tolerance. In another example, fabric typically has no gap tolerance, but rather, may have an overlap tolerance of 0.25 to 0.50 inches. Depending upon the contour of the substrate  30 , the natural path of the courses may converge or diverge beyond these tolerances. In an embodiment, the paths of the courses  28  are defined such that an overlap  56  is generated. The overlap  56  is configured such that at a relative maximum divergence between two abutting courses  28 , the respective edges of the abutting courses  28  are not further away than the gap tolerance. In the event that the overlap  56  exceeds the overlap tolerance, excess course material  14  is trimmed. The amount of excess to trim is determined based upon the sensed edge of the previously applied course  28 . For example, when applying unidirectional tape, the cutting assembly  48  is controlled to cut a profile along the edge of the course material  14  to essentially coincide with the edge of the previously applied course  28 . 
     In a preferred embodiment, the cutting assembly  48  is configured to function with a vacuum placement shoe S. In general, the vacuum placement shoe S is configured to generate a partial vacuum between the ply material  14  and the substrate  30 . As the end effector  32  advances and the ply material  14  is withdrawn from the vacuum placement shoe S, the ply material  14  is pressed upon the substrate  30  via atmospheric pressure. Specifically, the vacuum placement shoe S is configured to form a seal over a portion of the substrate  30  and generate a partial vacuum within the sealed area. The ply material  14  is fed through the sealed area and pressed upon the substrate  30  via atmospheric pressure. A more detailed description of the vacuum placement shoe is to be found in U.S. patent application Ser. No. 10/437,067, entitled VACUUM ASSISTED PLY PLACEMENT SHOE AND METHOD, filed on May 14, 2003, by Roger J. LEDET, Arnold J. LAUDER, and Matthew J. SHEWFELT, the disclosure of which is hereby incorporated in its entirety. 
       FIG. 4  is an exploded view of a ply layup according to an embodiment of the disclosure. As shown in  FIG. 4 , a ply  58  is consolidated upon the form  16 . That is, the courses  28  are applied to the form  16  and together these courses generate the ply  58 . In the example illustrated in  FIG. 4 , the separator film  40  is shown severed into strips  40 A and  40 B with the strip  40 A covering the portion of the course material  14  utilized to generate the ply  58  and the strip  40 B covering a trimmed excess course material  14 B. In another embodiment, the separator film  40  is essentially left intact during edge cutting operations. For example, the cutting assembly  48  is disposed upon the course material  14  side rather than the separator film  40  side and the cutting assembly  48  is configured to substantially leave the separator film  40  uncut as the course material  14  is cut. 
     According to an embodiment, the separator film  40  is removed following fabrication of the ply  58 . It is an advantage of this embodiment that the separator film  40  substantially prevents the excess course material  14 B from adhering to the previously applied course  28 . As shown in  FIG. 4 , the separator film  40 A substantially prevents the excess course material  14 B from adhering to the previously applied course  28 . In addition, the separator film  40 A facilitates protection of the ply  58  from dust, debris, and physical insult such as, for example, scratches, abrasion, and the like. In various embodiments, the separator film  40  is removed prior to or during application of successive courses of the course material  14  to the substrate  30 , as is the case when edges of successive courses of the course material  14  are overlapped. In such instances, a take up reel, for example, is configured to accumulate the separator film  40 ,  40 A and/or  40 B, and/or the excess course material  14 B. A suitable take up reel for use with the MAL  10  is described in U.S. patent application Ser. No. 10/975,433, entitled, AUTOMATED FABRIC LAYUP SYSTEM AND METHOD, filed on Oct. 29, 2004, by W. Robert NELSON, Michael C. DOWLING, Mark K. STEPHEN, Raymond L. ROYAL, and C. Tim HARBAUGH, the disclosure of which is hereby incorporated in its entirety. 
       FIG. 5  is a block diagram of a system  60  suitable for use with the MAL  10 . As shown in  FIG. 5 , the system  60  includes a controller  62 . The controller  62  is operable to execute computer readable code. In this regard, the system  60  includes a set of computer readable instructions or code  64 . According to the code  64 , the controller  62  is configured to access a file  66 . This file  66  includes one or more of the following: a computer readable model of the composite item; a computer readable representation of the surface of the layup form or the form  16 ; a computer readable representation of the edges of the form  16 ; the thickness of the composite item; a source code based upon at least one of the composite item and the form  16 ; a set of movement instructions based upon the source code; data gathered while laying up the composite item; timestamp information; positional information; identification numbers; and the like. The controller  62  is further configured to communicate across a network  68 . The network  68  is optionally included to provide additional data storage and/or processing capabilities. In this regard, the network includes a database  70  and a server  72 . The database  70  is configured to store a copy of the code  64  and/or file  66 . The server  72  is configured to generate, store, and perform any suitable processing of the code  64  and/or file  66 . In this manner, composite items generated on computer aided design (CAD) machines such as the server  72 , for example, may be forwarded to the MAL  10 . In addition, the server  72  is operable, via the network  68 , to forward updates for the code  64  and/or file  66 . In addition, the system  60  optionally includes a memory  74 . If present, the memory  74  is configured to store a copy of the code  64  and/or file  66 . 
     Also shown in  FIG. 5  is a positioning device controller  76  to control the robotic vehicle  12  and/or other such positioning devices. The positioning device controller  76  is optionally included in the system  60  depending upon the requirements of the various actuators and/or servo motors of the MAL  10 . That is, depending upon the particular configuration of the MAL  10 , a plurality of actuators and/or servo motors modulate the rotation, position, speed, direction, and the like of the various components of the MAL  10 . More particularly, these actuators and/or servo motors of the robotic vehicle  12  and/or positioning device are at least configured to advance the robotic vehicle  12  or otherwise modulate the various axes of the end effector  32  and/or MAL  10 . If present, parameters of the positioning device controller  76  are based upon the specification of the various actuators, servos, and/or the controller  62 . The positioning device controller  76 , if present, is configured to control some or all of these actuators and/or servo motors. In addition, these actuators and/or servo motors are optionally operable to be modulated by the controller  62  directly, and thus, the system  60  may not include the positioning device controller  76 . 
     In addition, the controller  62  is configured to receive signals from the sensor  38  and, in response to these signals, determine the position of the edge  42  of a previously applied course  28 . For example, employing an optical sensor, image signals are received from the sensor  38  and the controller  62 , utilizing image analysis algorithms, identifies differences between the edge  42  and the underlying substrate  30 . In a particular example, the separator film  40  is a white or light color and the course material  14  and form  16  are black or a relatively darker color. Thus, by identifying an interface between the white and black regions, the position of the edge is determined. In another example, the course material  14  is a relatively light color and the separator film  40  is a relatively darker color. Similarly, other differentiating optical characteristics may be employed to determine the edge. In another example, the sensor  38  includes feelers that contact the substrate and signals from the sensor  38  are utilized to determine a height difference between the previously applied course  28  and the underlying substrate  30 . 
     The controller  62  is further configured to modulate any suitable actuator such as, for example, servo motor, rack and pinions, linear drive belts, linear slides, X-Y tables, pneumatic rams, linear actuators, and the like. In particular, the controller  62  is configured to control the action of the actuator  52  in response to the sensed edge of the previously applied course  28 . In this manner, a profile is cut upon an edge of the course material  14 , by the cutting assembly which substantially conforms to the sensed edge. 
     The system  60 , optionally, further includes a plurality of sensors configured to sense the various suitable operating conditions or attributes of the MAL  10 . Examples of suitable attributes include some or all of the temperature of the course material  14 , the temperature at the location where the separator film  40  is separated from the course material  14  (release point), feed rate and direction, material placement, backing integrity, supply of course material  14 , and/or the like. 
     The system  60  optionally includes a heater  80 . The heater  80  includes any suitable heating device such as, for example an electrical heating element and blower, infrared device, induction heater, and/or the like. In a particular example, the heater  80  includes a heating element and a blower configured to direct a stream of heated air as appropriate. In addition, the heater  80  optionally includes a nib heater, chute heater, and release point blower. If present, these devices are modulated by the controller  62 . The nib heater applies a controlled amount of heat to the form  16 , the course material  14  and/or the separator film  40  in response to controlling signals generated by the controller  62 . Similarly, the chute heater applies a controlled amount of heat to the course material  14  and/or the separator film  40  in response to controlling signals generated by the controller  62 . In addition, the release point blower directs a flow of air toward the release point in response to controlling signals generated by the controller  62 . 
       FIG. 6  is a system architecture for the controller  62  suitable for use in the system  60 . As shown in  FIG. 6 , the controller  62  includes a processor  90 . This processor  90  is operably connected to a power supply  92 , memory  94 , clock  96 , analog to digital converter (A/D)  98 , and an input/output (I/O) port  100 . The I/O port  100  is configured to receive signals from any suitably attached electronic device and forward these signals to the A/D  98  and/or the processor  90 . If the signals are in analog format, the signals may proceed via the A/D  98 . In this regard, the A/D  98  is configured to receive analog format signals and convert these signals into corresponding digital format signals. Conversely, the A/D  98  is configured to receive digital format signals from the processor  90 , convert these signals to analog format, and forward the analog signals to the I/O port  100 . In this manner, electronic devices configured to receive analog signals may intercommunicate with the processor  90 . 
     The processor  90  is configured to receive and transmit signals to and from the A/D  98  and/or the I/O port  100 . The processor  90  is further configured to receive time signals from the clock  96 . In addition, the processor  90  is configured to store and retrieve electronic data to and from the memory  94 . Furthermore, the processor  90  is configured to determine signals operable to modulate the positioning device controller  76  and thereby control the various actuators and/or servo motors of the MAL  10  to exert a particular force and/or rotate to a particular degree. 
     According to an embodiment of the disclosure, the processor  90  is configured to execute the code  64 . Based on this set of instructions and signals from the various components of the MAL  10 , the processor  90  is configured to determine a set of controlling signals and forward these signals to the heater  80 , cutting assembly  48 , and the like. 
       FIG. 7  illustrates steps involved in a method  110  of placing plies to produce a composite structure or product. Prior to the initiation of the method  110 , a composite product is designed and, based on this design, a series of computer readable instructions specifying attributes of the composite product, such as the item  18 , is generated. In addition, a maximum width of material is determined based upon contours of the item  18 . For example, the contour along the course paths are determined and if a contour exceeds a recommended contour for a particular width of course material, a narrower or otherwise more accommodating material is selected and the course paths are re-calculated as appropriate. 
     Furthermore, the interfaces  46  between plies  58  laid in a similar warp direction are determined. If two or more of the interfaces  46  approximately overlap, course paths of at least one of the plies are adjusted or offset and the course paths are re-calculated as appropriate. The computer readable instructions are utilized to control the operations of the MAL  10 . In addition, a form or tool such as the form  16  is designed and constructed based upon the design of the composite product. Furthermore, the supply roll  34  is installed in the end effector  32  and the course material  14  is threaded through the end effector  32 . 
     Moreover, co-ordinated movements of a plurality of robotic vehicles  12  are optionally determined. These co-ordinated movements, if present, are stored to the file  66  and utilized to fabricate the item  18 . An example of the co-ordinated movements include instructions for a plurality of the robotic vehicles  12  to essentially simultaneously apply the course material  14  to the form  16 , thereby increasing the material lay down rate as compared to conventional ATLMs. Another example of the co-ordinated movements include instructions for the plurality of the robotic vehicles  12  to essentially simultaneously apply a woven pattern of the course material  14  to the form  16 , thereby increasing the integrity of the item  18  as compared to conventional ATLMs. 
     At step  112 , the method  110  is initiated by turning on the various components of the MAL  10  described herein above and executing the computer readable instructions. 
     At step  114 , the course material  14  is modulated by the action of the positioning device  12  and/or the supply roll  34 . For example, in response to the end of the course material  14  differing from the edge of the form  16 , the course material  14  is in position to be cut by the cutting assembly  48 . It is to be noted that in an embodiment, the course material  14  is essentially always cut along one or both edges (profiles) and that the step  114  is optionally performed to position the course material  14  for a leading edge cut. It is an advantage of this embodiment that a substantially continuous band of edge material is maintained throughout placement of the course material  14  to facilitate removal of the excess course material  14 B from the form  16 . 
     At step  116 , instructions from the file  66  are utilized for cutting an appropriate leading edge and/or profile for the course material  14  at the start of a course. In response to the instructions, the cutting assembly  48  cut the leading edge and/or profile. In addition, profile and diagonal cuts are performed in conjunction with movement of the end effector  32  relative to the form  16 . In this regard, cutting operations and movement of the positioning device  12  are generally performed concurrently. In addition, while the course material  14  is being advanced, edge profile cuts based on the file  66  are performed on the course material  14  by the cutting assembly  48 . In another embodiment, an edge of a previously applied course  28  is sensed in a manner similar to step  120  and the profile of the course material  14  is cut in a manner similar to step  122  prior to and/or during the step  116 . 
     At step  118 , the course material  14  is “tacked” to the substrate  30 . The substrate  30  includes, at least, the form  16  and/or a previously applied course  28 . For example, the positioning device  12  is controlled to move the end effector  32  to a starting position for the course  28  and into a suitable orientation. A downward force is applied to the course material  14 , pressing the course material  14  down upon the form  16  with sufficient force to cause adhesion. In addition, the location on the form  16  is determined based upon the series of computer readable instruction and/or the location of a previously positioned course material  14 . As described herein, the path of a course  28  placed adjacent to a previously applied course  28  is offset to generate the overlap  56  on the previously applied course  28 . This overlap  56  or a portion thereof is cut away during profiling of the edge of the course material  14  at step  122 . 
     At step  120 , a previously applied course  28 , if present, is sensed. That is, when applying a second course  28 , the edge of the first course is sensed. More particularly, the edge  42  of the first course  28  at the interface between the first course  28  and the path of the second course  28  is sensed. In a similar manner, subsequent courses  28  are sensed. 
     At step  122 , the profile of the course material  14  is generated in response to the edge sensed at step  120 . For example, in response to signals from the sensor  38 , the controller  92  determines a profile that corresponds to the sensed edge. The controller  92  further generates signals to modulate the cutting assembly  48  according to the determined profile. These signals are forwarded to the actuator  52 . In this manner, a profile is generated upon the course material  14  that substantially corresponds to the previously applied course  28 . Depending upon the course material  14 , this profile is generated such that it overlaps, abuts, or approaches the edge of the previously applied course  28 . A more detailed description of this method of slitting and applying plies is to be found in U.S. patent application Ser. No. 11/058,267, entitled, SLIT-COURSE PLY PLACEMENT DEVICE AND METHOD, filed on Feb. 16, 2005, by Roger J. LEDET, Trevor M. MCDONALD, and Arnold J. LAUDER, the disclosure of which is hereby incorporated in its entirety. 
     At step  124 , the course material  14  is dispensed along a path across the form  16 . As described herein, in order to minimize deformations in the course material  14  (e.g., wrinkles), this path is typically calculated to coincide with a “natural path” based upon any contours in the form  16 . As the end effector  32  is controlled along the path across the form  16 , the course material  14  is withdrawn or “free wheeled” from the supply roll  34  via the movement of the end effector  32  relative to the substrate  30 . That is, the tacked portion of the course material  14  acts to pull course material  14  from the supply roll  34 . In other embodiments, the course material  14  is advanced via the action of the supply roll  34 , any suitable feed assembly, take-up roll, and the like. As the course material  14  is dispensed or applied, one or more edge profiles of the course material  14  are cut, as described at step  122 , via the action of the cutting assembly  48  in response to the edge sensed at step  120 . 
     At step  126 , the placement of the course material  14  on the form  16  is optionally evaluated. For example, an operator or a sensor senses the relative position of the courses  28  and determine if the distance between these courses is within a predetermined tolerance. If the distance between these courses is not within the predetermined tolerance, an error may be generated at step  128 . If the distance between these courses is within the predetermined tolerance, it is determined if the end of the path has been reached at step  130 . In addition to placement of the course material  14 , wrinkles, bridges, foreign objects, debris, and the like are optionally sensed for by an operator and/or sensor. If any such abnormalcy is sensed, an error is generated. In addition or alternatively, the placement of the courses  28  is optionally evaluated following the completion of the ply  58 . It is an advantage of an embodiment that by leaving the separator film  40  on the course material  14  until the completion of the ply  58 , the ply  58  is protected from contamination and/or physical insult that may occur during evaluation. 
     At step  130 , it is determined if the end of the course has been reached. More specifically, it is determined if the course material  14  that is approaching the cutting assembly  48  is to be end cut. If, based on the series of computer readable instruction, it is determined the course material  14  has not advanced to the end of the course, the edge of the previously applied course is sensed at step  120 . If, it is determined the course material  14  has advanced to the end of the course, the course material  14  is end cut at step  132 . 
     At step  132 , the end of the course material  14  is cut based upon the series of computer readable instruction contained in the file  66 , the orientation of a previously positioned course material  14 , and/or the location of a previously positioned course material  14 . 
     At step  134 , it is determined if the placement of course material  14  on the composite product has been completed. For example, if all of the computer readable instructions in the file  66  have been completed, it may be determined that the placement of plies  58  for the item  18  has been completed and the MAL  10  may idle until another series of computer readable instructions is initiated. If is determined the placement of course material  14  for the item  18  is not completed, an additional course material  14  placement may proceed at step  114 . 
     Following the method  110 , the composite product may be cured in any suitable manner. In the aerospace industry, thermoset resins are generally utilized to pre-impregnate ply material. These thermoset resins are typically cured at an elevated temperature and pressure for a predetermined amount of time. Times, pressures, and temperatures may be selected depending on the resin used, the size and thickness of the composite product, and the like. 
     Although an example of the end effector  32  is shown being controlled by the robotic vehicles  12 , it will be appreciated that other control systems can be used. In this regard, a gantry system, robotic armature, mandrel, or other such positioning devices that support and control the movement of any suitable end effector are suitable for use with end effector  32 . Also, although the MAL  10  is useful to place plies for composite products in the airline industry it is also suitable for use in other industries that construct composite product. These industries include, but are not limited to, automobile, marine, spacecraft, building, and consumer products. 
     The many features and advantages of the disclosure are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the disclosure that fall within the true spirit and scope of the disclosure. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the disclosure to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the disclosure.

Technology Category: 7