Patent Publication Number: US-2023150051-A1

Title: System and method for ultrasonic additive manufacturing

Description:
This application is a continuation-in-part of U.S. application Ser. No. 16/421,727, filed May 24, 2019, which claims priority to U.S. Provisional Application No. 62/683,793, filed Jun. 12, 2018, the complete disclosures of both of which are incorporated herein in their entireties. 
    
    
     BACKGROUND OF THE INVENTION 
     This application relates generally to ultrasonic additive manufacturing (UAM) methods and, more particularly, to the use of ultrasonic AM in a portable device for in-place repair or joining of components. 
     Additive manufacturing (AM) is the term given to manufacturing processes in which component features are formed through the sequential application of thin, substantially two-dimensional layers. Each layer is made at a specified thickness and many layers are formed in a sequence with the two dimensional layer shape varying from layer to layer to achieve a desired three-dimensional component structure. 
     In UAM, solid metal objects are formed by ultrasonically welding successive layers of thin metal tape into a three-dimensional weld. The tape layers are held to a substrate under pressure and high-frequency (typically 20,000 hertz) ultrasonic vibrations are applied using a sonotrode to produce a solid-state weld between the tape and the substrate and/or between tape layers. Machining operations (i.e., subtractive manufacturing processes) may be applied during or after UAM operations to provide particular features to the component. 
     SUMMARY OF THE INVENTION 
     An illustrative aspect of the invention provides a welding apparatus comprising a guide rail arrangement removably attachable to a welding target. The guide rail arrangement includes at least one guide rail having a lateral channel in which a gear rack is disposed and a plurality of supports attached to each of the at least one guide rail. The supports are removably attachable to a surface of the welding target and are sized and configured for maintaining the at least one guide rail at a uniform distance from the surface. The welding apparatus further comprises a carriage mounting arrangement removably mountable to the guide rail arrangement. The carriage mounting arrangement comprises for each guide rail of the at least one guide rail, a beam support mountable to the guide rail for slidable movement there-along. The carriage mounting arrangement further comprises a first drive mechanism attached to one of the beam supports. The first drive mechanism includes a drive gear configured for engaging the gear rack of a target-mounted guide rail when said one of the beam supports is mounted to the target-mounted guide rail, whereby rotation of the drive gear causes said one of the beam supports to move along said target-mounted guide rail. The carriage mounting arrangement also comprises a first elongate beam mounted to the beam support so that when the guide rail assembly is attached to the target surface and the beam support is mounted to its respective guide rail, the first elongate beam is parallel to the target surface or to a plane tangential to the target surface. The welding apparatus also comprises a welding carriage comprising a carriage housing mounted to the first elongate beam and having an ultrasonic weld head disposed therein. The weld head comprises a sonotrode extending toward the target surface when the welding apparatus is in a welding configuration in which the guide rail arrangement is attached to the target surface and the carriage mounting arrangement is mounted to the guide rail arrangement. The sonotrode is operable to conduct ultrasonic vibrations into and through a layer of feedstock material deposited on the target surface to weld the feedstock material to the target surface. 
     Another illustrative aspect of the invention provides a method of applying a weld to a welding target. The method comprises attaching a guide rail arrangement to the welding target, the guide rail arrangement including at least one guide rail. The method further comprises movably mounting to the guide rail arrangement, a weld head carriage comprising a carriage housing, a rail follower assembly, and an ultrasonic weld head comprising a sonotrode. The rail follower assembly is placed in engagement with each of the at least one guide rail for movement there-along. The method still further comprises positioning the weld head carriage at a starting position adjacent a target surface of the welding target, depositing feedstock material onto the target surface, and extending at least a portion of the weld head carriage toward the target surface so that the sonotrode engages the deposited feedstock material, thereby applying a normal welding force to the deposited feedstock material and the welding target. The method also comprises initiating relative movement between the weld head carriage and the guide rail arrangement and conducting ultrasonic vibrations into the deposited feedstock material and the welding target, thereby welding the deposited feedstock material to the target surface and adding a welded feedstock layer to the welding target. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the following detailed description together with the accompanying drawings, in which like reference indicators are used to designate like elements, and in which: 
         FIG.  1    is a side view of a welding apparatus according to an embodiment of the invention; 
         FIG.  2    is a front view of the welding apparatus of  FIG.  1   ; 
         FIG.  3    is a section view of the welding apparatus of  FIG.  1   ; 
         FIG.  4    is a front view of the welding apparatus according to an embodiment of the invention; 
         FIG.  5    is a section view of the welding apparatus of  FIG.  4    with internal features removed for simplicity; 
         FIG.  6    is a flow diagram of a method of forming a weld according to an embodiment of the invention; 
         FIG.  7    is a sectioned perspective view of two pipe sections to be joined using a UAM system according to the invention; 
         FIG.  8    is a perspective view of the pipe sections of  FIG.  7    and the guide rails of a welding apparatus according to an embodiment of the invention; 
         FIG.  9    is a perspective view of the pipe sections of  FIG.  7    and a welding apparatus according to an embodiment of the invention; 
         FIG.  10    is a perspective view of the pipe sections of  FIG.  7    and the welding apparatus of  FIG.  9   ; 
         FIG.  11    is a cross-sectional view of the pipe sections of  FIG.  7    and the welding apparatus of  FIG.  9   ; 
         FIG.  12    is a sectioned perspective view of two pipe sections and a welding apparatus according to an embodiment of the invention; 
         FIG.  13    is a side view of the pipe sections and welding apparatus of  FIG.  12   ; 
         FIG.  14    is a front view of an arcuate guide member according to an embodiment of the invention; 
         FIG.  15    is a side view of the arcuate guide member of  FIG.  14   ; 
         FIG.  16    is an end view of the pipe sections and welding apparatus of  FIG.  12   ; 
         FIG.  17    is an end view of the pipe sections and welding apparatus of  FIG.  12   ; 
         FIG.  18    is a cross-sectional view of the pipe sections and welding apparatus of  FIG.  12   ; 
         FIG.  19    is a side view of two pipe sections and a welding apparatus according to an embodiment of the invention; 
         FIG.  20    is a is a cross-sectional view of the pipe sections and welding apparatus of  FIG.  19   ; 
         FIG.  21    is a front view of a bidirectional jack according to an embodiment of the invention; 
         FIG.  22    is a top view of the bidirectional jack of  FIG.  21   ; 
         FIG.  23    is a front section view of the bidirectional jack of  FIG.  21   ; 
         FIG.  24    is a perspective view of two pipe sections and a welding apparatus according to an embodiment of the invention; 
         FIG.  25    is a side view of the pipe sections and welding apparatus of  FIG.  24   ; 
         FIG.  26    is an end view of the welding apparatus of  FIG.  24   ; 
         FIG.  27    is a cross-sectional view of the welding apparatus of  FIG.  24   ; 
         FIG.  28    is a cross-sectional view of a pipe section and a welding apparatus according to an embodiment of the invention; 
         FIG.  29    is a cross-sectional view of a pipe section and a welding apparatus according to an embodiment of the invention; 
         FIG.  30    is a top view of a welding apparatus according to an embodiment of the invention attached to a planar welding target; 
         FIG.  31    is a side view of the welding apparatus and target of  FIG.  30   ; 
         FIG.  32    is a section view of a portion of the welding apparatus and target of  FIG.  31   ; 
         FIGS.  33   a  and  33   b    are views of a portion of a welding apparatus according to an embodiment of the invention; and 
         FIGS.  34 - 36    are perspective views illustrating a sequence of operation of a welding apparatus according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While the invention will be described in connection with particular embodiments and manufacturing environments, it will be understood that the invention is not limited to these embodiments and environments. On the contrary, it is contemplated that various alternatives, modifications and equivalents are included within the spirit and scope of the invention as described. 
     The present invention provides methods and apparatus for joining or repairing components using a portable welding assembly that includes a material deposition apparatus and a sonotrode or similar energy input device. In general, the methods of the invention allow the use of UAM in operations in which a desired relative motion is established and maintained between the material deposition and welding apparatus and the target component(s) being assembled or repaired. The relative motion may be an orbital rotation (e.g., for repairing or joining pipe sections) or may be translational (e.g., parallel to, orthogonal to, or otherwise angled relative to a surface of the target component(s)). The relative motion may be established by holding the target component or components fixed and moving the material deposition and welding apparatus (e.g., rotationally around an axis or translationally along the surface of the target component(s). Alternatively, the material deposition and welding apparatus may be fixed and the target component(s) translated or revolved. 
     Accordingly, in some embodiments, the welding assembly is housed in a carriage configured to move along a guided track system (orbital or planar) or to be moved within a planar framework, the track or framework being temporarily or permanently attached to the welding target. In other embodiments, the welding assembly is part of an assembly configured to grasp and hold the component(s) in engagement with the welding assembly and to translate or rotate the component(s) relative to the welding assembly. 
     Illustrative embodiments of the invention are described in more detail in the following paragraphs. 
       FIGS.  1 - 3    depict a UAM apparatus  100  according to an embodiment of the invention. The UAM apparatus  100  is usable for ultrasonic, in-situ welding for repair or construction of a fixed structure (welding target). In the illustrative application of  FIG.  1 - 3   , the structure consists of two plates  10 ,  12  which are to be welded together along a joint line  40 . (It will be understood that the structure could also be a single plate with two portions  10 ,  12  separated by a crack or flaw  40  requiring repair.) The material of the welding target structure (substrate material) may be any metallic material that can be ultrasonically welded. Typical substrate materials would include both ferrous and non-ferrous alloys such as steel, stainless steel alloys, aluminum, copper-based alloys, nickel-based alloys, and other families of alloys. The UAM apparatus  100  comprises a material deposition and welding carriage  110  and a pair of parallel guide rails  130 . Each guide rail  130  may be a continuous rail member or may be a plurality of rails segments joined together. In some embodiments, the guide rails  130  may be flexible in order to allow them to follow the contour of a non-planar welding target surface. The guide rails  130  are each supported by a plurality of rail supports  132  which may be temporarily or permanently attached to the structure to be welded. The attachment mechanism need only be sufficient to counter the forces applied to the structure during the welding operation. Suitable mechanisms may include, without limitation, welding, reversible or permanent chemical or thermal bonding, hydraulics, mechanical fasteners (e.g., screws, bolts, clamps, etc.), and magnets. The supports  132  are mounted so that the guide rails  130  are positioned on opposite sides of a line along which the structure is to be welded. In the illustrated example, the rails  132  are mounted along opposite sides of the joint line  40 . 
     While the illustrated embodiment shows a guide rail arrangement having two rails, it will be understood that some embodiments of the invention may use only a single rail (monorail) arrangement. Other embodiments could make use of guide rail arrangements having more than two rails. 
     While the illustrated example of this embodiment shows the guide rails  130  mounted to a planar surface, they may also be mounted to curved surfaces. For example, the guide rails  130  could be mounted to the outside of a pipe on a line parallel to the pipe centerline. 
     With reference, in particular, to  FIG.  3   , the material deposition and welding carriage  110  comprises a carriage housing  112  in which is disposed a weld head  120  comprising a sonotrode  121  and a reel or other source  152  of weldable feedstock  150 . The weldable feedstock  150  will typically be in the form of a thin tape that can be drawn from the source  152  and will typically be of a similar metal alloy to the substrate(s) to which it is to be applied. Accordingly, typical feedstock materials include a stainless steel alloys, aluminum alloys, copper-based alloys, nickel-based alloys, and other non-ferrous and ferrous alloys capable of being ultrasonically welded. While the feedstock material is typically similar to the substrate material, dissimilar feedstock metals may also be used for some applications. The carriage housing  112  is mounted to a rail follower assembly in the form of an undercarriage  114  configured to engage the guide rails  130 . The undercarriage  114  is further configured so that the carriage  110  is movable along the guide rails  130  and so that it provides a reactive retaining force F R  that holds the undercarriage  112  in engagement with the guide rails  130  in response to the application of a welding force F W  to the structure being welded. In some embodiments, the guide rails  130  may be configured to provide a lower surface that can be engaged by the undercarriage  114  for transmission of the reactive retaining force F R . The undercarriage  114  may include wheels or bearings configured to facilitate the motion of the carriage  110  along the rails  130 . 
     The carriage  110  is configured so that as it moves along the guide rails  130  in the direction D, feedstock  150  is drawn from the feedstock source  152  to pass between the sonotrode  121  and the surface of the structure to be welded. The weld head  120  is mounted so as to allow application of the welding force F W  to the feedstock  150  and the structure surface. In some embodiments and applications, the weight of the device may provide a sufficient force. In other embodiments, internal or external electrical, mechanical or electromechanical mechanisms can be used to apply or contribute to the welding force F W . A simple example of an internal mechanical mechanism would be a screw mounted to the carriage body  112  that turns to provide downward force on the weld head  120  and the sonotrode  121 . 
     At the same time the welding force F W  is being applied to the feedstock  150 , the sonotrode transducer  122  is energized to produce high frequency vibration to weld the feedstock  150  to the structure (in this case, to the surfaces of the two plates  10 ,  12 ). In the illustrated example, the welded feedstock layer  150 ′ bridges the joint line  40  and serves as a first layer of an ultrasonic weld to permanently join the two plates  10 ,  12 . It will be understood that after application of this first layer of welded feedstock  150 ′, the carriage  110  may be returned to its starting point to apply a subsequent layer  150 ′. The process may be repeated as many times as necessary to produce the desired weld. 
     The material deposition and welding carriage  110  may also comprise an on-board data processor  160  in communication with the sonotrode transducer  122  and feedstock dispensing mechanism. The processor  160  may also be in communication with external processors or user input devices. In some embodiments, this may be by wireless connection via a network. The processor  160  may also be in communication with an internal or external power source connected to the sonotrode transducer  122 . In alternative embodiments, control of the material deposition and welding carriage  110  may be accomplished via other means such as from an alternate location, via wireless controls (e.g., from an alternate location) or via some other local device able to communicate with the carriage  110 . 
     The apparatus  122  may also include a sensor package  162  mounted to the carriage housing  112 . The sensor package  162  may be in communication with the data processor  160  and could include, for example, optical, laser, thermal or other sensors configured and positioned to capture data on the applied feedstock  150 ′. The captured data may be analyzed to assess the integrity of the welded layer  150 ′. 
     In favored embodiments of the invention the deposition and welding of feedstock material is coincident with movement of the weld head carriage relative to the welding target area of the target structure. In some embodiments, this movement is provided and controlled manually by a user of the apparatus. In other embodiments, the carriage may be self-propelled or propelled by a drive system incorporated into the guide rail arrangement.  FIGS.  4  and  5    illustrate a simple variation of the previously described UAM apparatus  100  in which the undercarriage  114  of the carriage  110  includes a drive mechanism. The drive mechanism in this case is a plurality of gears  118  driven by one or more motors (not shown) within a motor housing  116 . The gears  118  are configured to engage a rack  134  attached to the underside of each rail  130 . Revolution of the gears  118  causes the carriage  110  to be propelled along the rails  130 . Any suitable self-propulsion mechanism may be used and may be controlled remotely or by the on-board processor  160 . Alternatively, a manual drive mechanism may be operatively connected to the drive mechanism 
     With reference to  FIG.  6   , a generalized method of applying a weld using the UAM apparatus  100  or apparatus according to other embodiments of the invention includes attaching the guide rail arrangement to the welding target at S 110 . The welding target may be a single metal object to an area of which a weld is to be applied or the welding target may be a plurality of objects to be joined together. In some applications, the welding target may be permanently affixed in a structural environment. In other applications, the welding target may itself be movable for placement in a work fixture. Depending on the application, the guide rail arrangement may be permanently or temporarily attached to the surface of the target object (e.g., by welding, bonding, or magnetically adhering) surrounding or adjacent a target area on the surface of the welding target. In some applications, the rail or rails of the guide rail arrangement may be attached in separate pieces and joined in place along with their supports. 
     At S 120 , the weld head carriage is mounted to the guide rail arrangement. In embodiments where the welding target is immobile, this may include mounting the rail follower assembly of a portable, mobile carriage unit to the rails of the guide rail arrangement. In this scenario, the rails remain stationary along with the welding target and the relative movement of the carriage is established by actual movement of the carriage within the surrounding environment. As will be discussed in more detail below, however, there are some embodiments of the invention in which the weld head carriage is immovably attached to a work fixture and the welding target is movably supported by the work fixture. In these embodiments, the action of mounting the carriage is accomplished by positioning the welding target within the fixture so that the rail follower assembly of the carriage can be mounted to the rails. Motion of the carriage relative to the rails can then be established by the movement of the welding target and the rails within the surrounding environment while the carriage remains motionless. 
     At S 130 , the carriage is positioned at a starting position relative to the target area of the target object surface to which a weld is to be applied. At S 140  motion of the carriage relative to the rail or rails of the guide rail arrangement is initiated by causing the carriage to move or by causing the weld target and the rails to move. Simultaneously with or shortly after initiation of relative movement, feedstock material from the feedstock source of the carriage is applied to the target are of the surface at S 150  and the sonotrode engages the feedstock source at S 160 , thereby applying a welding force F W  to the feedstock material and the surface of the welding target. At S 170 , the sonotrode is activated to conduct ultrasonic vibrations into the feedstock material and the welding target, thereby welding the feedstock material to the welding target and forming a weld layer. Once the carriage reaches the end of the target area, the sonotrode may be deactivated and disengaged, feedstock application/deposition may be halted, and movement of the carriage halted. 
     It is contemplated that the feedstock material used in the present invention may provide only a very thin layer that, by itself, would not form a robust weld. It is therefore an objective of the present invention to repeat the actions of the above described method to build a robust, multi-layer weld. Accordingly, the carriage may be repositioned at the starting position and actions S 140 , S 150 , S 160 , and S 170  repeated to apply another weld layer to the target object. The actions may be repeated any number of times to build up a desired weld as in typical UAM processes. Additional machining or other processing techniques can then be applied. 
     In some applications (e.g., joining pipe sections), the guide rails may form a continuous circuit around a circumference of the target object. In such applications, there may be no need to halt material deposition and welding actions or to reposition the carriage for a second weld layer. Instead, the carriage may simply be allowed to continue circumferential movement around the target object, with each orbit providing a new weld layer to the target area. 
     The present invention may be of particular value in welding pipe or other cylindrical structures.  FIG.  7    illustrates an exemplary scenario in which two pipe sections  20 ,  30  having a common longitudinal center axis  25  are to be welded together. As shown, the free end  22  of the first pipe section  20  and the free end  32  of the second pipe  30  are in contact with one another (or are closely adjacent) at a joint interface  40 . 
       FIGS.  8 - 11    illustrate an orbital UAM system according to an embodiment of the invention that can be used for in-situ welding of the two pipe sections  20 ,  30 . This system takes the form of a welding apparatus  200  that comprises a mobile material deposition and welding carriage  210  and a guide rail arrangement having a pair of parallel circumferential guide rails  231   a ,  231   b  positioned so as to surround the pipe sections  20 ,  30 , respectively. The guide rails  231   a ,  231   b  are each supported by a plurality of rail supports  232  which may be temporarily or permanently attached to the structure to be welded. The supports  232  are mounted so that the guide rails  231   a  are positioned on opposite sides of the joint interface  40 . 
     As in the previous embodiment, the material deposition and welding carriage  210  comprises a carriage housing  212  in which is disposed a weld head  220  with a sonotrode  221  and a reel or other source  252  of weldable feedstock  250 . The carriage housing  212  is mounted to an undercarriage  214  configured to engage the guide rails  231   a ,  231   b . The undercarriage  214  is further configured so that the carriage  210  is movable along the guide rails  231   a ,  231   b  in an orbital fashion around the joint interface  40 . It is also configured to provide a radially outward retaining force that holds the undercarriage  212  in engagement with the guide rails  231  in response to the application of a radially inward welding force to the structure being welded. The undercarriage  214  may include wheels or bearings configured to facilitate the motion of the carriage  210  along the rails  231 . 
     The carriage  210  is configured so that as the carriage  210  moves along the guide rails  231   a  in the orbital direction D, feedstock  250  is drawn from the feedstock source  252  to pass between the sonotrode  221  and the surface of the structure to be welded.  FIG.  9    shows the carriage at an initial position and  FIGS.  10  and  11    show the carriage  210  after it has moved a quarter of the way along its orbital path. The weld head  220  is mounted so as to allow application of the welding force F W  to the feedstock  250  and the structure surface as the carriage  210  moves along this path. As before, internal or external electrical, mechanical or electromechanical mechanisms can be used to apply or contribute to the welding force F W . 
     At the same time the welding force W F  is being applied to the feedstock  250 , the sonotrode transducer  222  is energized to produce high frequency vibration to weld the feedstock  250  to the structure (in this case, to the surfaces of the two pipe sections  20 ,  30 ). In the illustrated example, the welded feedstock layer  250 ′ bridges the joint line  40  and serves as a first layer of an ultrasonic weld to permanently join the two pipe sections  20 ,  30 . Upon completion of one orbit, the carriage  210  will have applied a complete first layer of welded feedstock  250 ′. The carriage  210  may simply continue to travel its orbital path to begin forming a second layer of welded feedstock  250 ′. The process may be repeated as many times as necessary to produce a desired weld without removal or shifting of the carriage  210 . 
     It will be understood that in the case of repairs, a complete circumferential weld layer may not be required. In such cases, the material deposition and welding carriage  210  may be commanded to deposit and sonically weld a feedstock layer at only a portion of the carriage orbit. Upon completion of deposition/welding of a layer over the target area, the carriage  210  could continue around its orbit until reaching the target area again, whereupon a second layer could be initiated over the target area, and so on until a desired weld is achieved. 
     In some applications, it may be desirable to produce an over-lapping weld to enlarge the joining area along or adjacent the joint line  40 . In such applications, the guide rails  231   a ,  231   b  could be shifted after formation of an initial circumferential weld, and the process repeated to produce a second weld over-lapping the first. 
     As in the previous embodiment, the material deposition and welding carriage  210  may also comprise an on-board data processor  260  in communication with the sonotrode transducer  222  and feedstock dispensing mechanism. The processor  260  may also be in communication with external processors or user input devices. In some embodiments, this may be by wireless connection via a network. The processor  260  may also be in communication with an internal or external power source connected to the sonotrode transducer  222 . The apparatus  222  may also include a sensor package  262  mounted to the carriage housing  212 . The sensor package  262  may be in communication with the data processor  260  and could include, for example, optical, laser, thermal or other sensors configured and positioned to capture data on the applied feedstock  250 ′. The captured data may be analyzed to assess the integrity of the welded layer  250 ′. 
       FIGS.  12 - 18    illustrate a particular orbital UAM system  1000  that can be used for in-situ welding of two pipe sections  20 ,  30  according to an embodiment of the invention. While this and other examples discussed herein illustrate the joining of two pipe sections, it will be understood that the system  1000  may be used for new fabrication (e.g., the joining of two pipe sections), for repair operations (e.g., of a crack in a single pipe section or of flawed joint between two sections), or for augmenting an existing structure, weld or joint. The system  1000  includes a welding arrangement  1100  comprising a welding carriage  1110 , a carriage support system  1200 , and a guide rail arrangement  1300  comprising a pair of parallel guide collar assemblies  1300   a ,  1300   b.    
     The guide collar assemblies  1300   a ,  1300   b  are each formed from a plurality of arcuate guide members  1310  that are attachable to one another to form a complete circular guide track. In the illustrated embodiment, there are two semi-circular guide members  1310 , but any number of smaller arced members could be used. Each guide member  1310  has an inner circumferential wall  1311  and an outer circumferential wall  1312  connected by a web  1313 . The inner and outer walls  1311 ,  1312  and the web  1313  collectively define a forward facing guide channel  1315 . Typically, the inner circumferential wall  1311  will be sized to fit around the outer diameter of the pipe sections  20 ,  30 . The outer circumferential wall  1312  may be sized and the web  1313  positioned so as to size the guide channel  1315  to receive a guide and/or drive mechanism of the carriage support and rive system  1200 . In particular embodiments, the guide member  1310  may have an inward facing outer gear rack  1318  along the inner side of the outer circumferential wall  1312 . The outer guide rack  1318  is sized and configured to operatively support and engage a drive gear of the carriage support and rive system  1200 . The guide member  1310  may also have an inner guide flange  1316  on the outer side of the inner circumferential wall  1311 . In alternative embodiments, the guide member  1310  may have an outward facing guide rack on the inner circumferential wall  1311  instead of the outer guide rack  1318 . The guide members  1310  may be assembled to one another in any suitable fashion that does not interfere with the reception of a guide mechanism into and along the guide channel  1315 . In particular embodiments, the guide members  1310  may include passages  1319  that are aligned with one another when the guide members  1310  are assembled and are configured for receiving a fastener (e.g., a machine screw or bolt) to removably hold the assembled guide members  1310  to one another. 
     As shown in  FIGS.  12  and  13   , a first set of guide members  1310  may be assembled to one another so as to form a first complete guide assembly  1300   a  surrounding the first pipe segment  20  and a second set of guide members  1310  may be assembled to one another to form a second complete guide assembly  1300   b  surrounding the second pipe segment  30  so as to be parallel to the first complete guide assembly  1300   a . As used herein, the term “parallel” may be applied to matching curves in parallel planes where every point on the first curve is equidistant form its corresponding point of the second curve. When so-installed, the guide members  1300   a    1300   b  provide substantially parallel guide rails. In some embodiments, only one of the two guide assemblies  1300   a ,  1300   b  need have a drive gear rack. 
     It will be understood that in some embodiments a single guide assembly may be used without departing from the spirit of the invention. In such embodiments, a monorail-type carriage may be used to engage the guide assembly. 
     The carriage support and drive system  1200  comprises a pair of support blocks  1220  configured to support a carriage mounting arrangement  1240 . The carriage mounting arrangement  1240 , which will be discussed in more detail below, includes one or more elongate beams  1230  having a polygonal or circular cross-section. Each support block  1220  is slidably mountable to one of the guide assemblies  1300   a ,  1300   b . In some embodiments, the support block  1220  is mountable to the guide assembly  1300   a ,  1300   b  by a drive arrangement  1210 . The drive arrangement  1210  includes a drive box  1211  attached to the support block  1220 . A guide and/or drive mechanism is attached to and disposed within the drive box  1211 . This mechanism is configured for engagement with and movement along the guide channel  1315  of the guide assembly  1300 . As shown in  FIG.  17   , in which the front face of the drive box  1211  is removed, the guide and/or drive mechanism may include a drive gear  1212  rotatably mounted to a shaft that is, in turn, mounted to the drive box  1211 . The drive gear  1212  is configured to engage the gear racks  1316 ,  1318  of the guide assembly  1300 . The drive gear  1212  may be rotated by a rotation mechanism. In some embodiments, the rotation mechanism may be an external wheel  1214  configured for manual rotation. In other embodiments, the rotation mechanism may be or include a motor configured to impart automated rotation of the drive gear  1212 . In either case, the rotation mechanism may be used to directly rotate the drive gear shaft. In some embodiments, however, the rotation mechanism may be coupled to the drive gear shaft by additional gearing housed within the drive box  1211 . 
     The carriage support and drive system  1200  may be assembled in place by mounting a first support block  1220  and drive arrangement  1210  to the forward guide assembly  1300   a  and a second support block  1220  and drive arrangement  120  to the rear guide assembly  1300   b  with the first and second support blocks  1220  connected by the beams  1230 . 
     As in the previous embodiments, the welding carriage  1110  comprises a carriage housing  1112  in which is disposed a weld head  1120  with a sonotrode  1121 . The carriage housing  1112  is mounted to the support blocks  1220  by the mounting arrangement  1240  that includes the beams  1230 . In some embodiments, such as the embodiment illustrated in  FIGS.  18  and  19   , the mounting arrangement  1240  may include a rigid frame  1241  having a sleeve  1242  for each beam  1230 . The sleeve  1242  is configured for receiving the beam  1230  there-through. In some embodiments, the sleeve  1242  may be configured to slidably receive the beam  1230 , thereby allowing the carriage  1110  to slide along the beam  1230 . This effectively allows the carriage  1110  to be translated parallel to the pipe segment axis  25  when the UAM system  1000  is attached to the pipe segments  20 ,  30  (or to a single pipe segment). 
     While  FIG.  12    shows two beams  1230 , additional beams may be used. Using multiple beams may facilitate controlled movement of the carriage  1110  along the beams. Such movement could be accomplished electrically via an appropriate motor (e.g., stepper, servo, etc.) and could be used to position the carriage  1110  anywhere along the beams  1230 . 
     It will be understood by those of ordinary skill in the art that activation of the drive mechanism engaging the guide assembly (e.g., rotating the drive gear  1212 ) results in the circumferential travel of the carriage support and drive system  1200  and the welding carriage  1110  around the pipe segments  20 ,  30  (or pipe) to which the system  1000  is attached. The frame  1241  is sized and configured so that the weld head  1120  is positioned or positionable for contacting and applying a welding force to a feedstock layer  1150 ′ applied to the surfaces of the pipe segments  20 ,  30  at the joint interface  40 . In the illustrated embodiment, the UAM system  1000  includes a feedstock magazine  1151  attached to the frame  1241  separate from the carriage  1110 . As the carriage and the magazine  1151  travel in the direction D, feedstock  1150  may be drawn from a reel  1152  disposed within the magazine  1151  and applied to the surfaces of the pipe segments  20 ,  30 . It will be understood that the carriage  1110  may alternatively carry an on-board reel or other source of feedstock  1150  as in the previous embodiments. 
     Operation of the UAM system  1000  is similar to that of the previous embodiment. As the carriage  1110  moves along the guide assemblies  1300   a ,  1300   b  in the orbital direction D, feedstock  1150  is drawn from the feedstock source  1152  to pass between the sonotrode  1121  and the surface of the structure to be welded. The weld head  1120  is mounted so as to allow application of the welding force to the feedstock  1150  and the structure surface as the carriage  1110  moves along this path. As before, internal or external electrical, mechanical or electromechanical mechanisms can be used to apply or contribute to the welding force. During operation, the carriage support and drive system  1200  provides a retaining force that holds the weld head  1120  in engagement with the feedstock  1150 ′ in response to the application of a radially inward welding force to the structure being welded. At the same time the welding force is being applied to the feedstock  1150 , the sonotrode transducer  1122  is energized to produce high frequency vibration to weld the feedstock  1150  to the structure (in this case, to the surfaces of the two pipe sections  20 ,  30 ). The welded feedstock layer  1150 ′ bridges the joint line  40  and serves as a first layer of an ultrasonic weld to permanently join the two pipe sections  20 ,  30 . Upon completion of one orbit, the carriage  1110  will have applied a complete first layer of welded feedstock  1150 ′. The carriage  1110  may simply continue to travel its orbital path to begin forming a second layer of welded feedstock  1150 ′. The process may be repeated as many times as necessary to produce a desired weld without removal or shifting of the carriage  1110 . 
     In some applications, it may be desirable to produce an over-lapping weld to enlarge the joining area along or adjacent the joint line  40 . In such applications, the guide assemblies  1300   a ,  1300   b  could be shifted after formation of an initial circumferential weld, and the process repeated to produce a second weld over-lapping the first. In embodiments where the frame  1241  is slidable along the beams  1230 , however, the frame  1241 , carriage  1110  and magazine  1151  may be moved along the pipe centerline  25  to a new position to form the overlapping layer without moving the guide assemblies  1300   a ,  1300   b.    
     As in the previous embodiment, the welding carriage  1110  may also comprise an on-board data processor  1160  in communication with the sonotrode transducer  1122  and feedstock dispensing mechanism. The processor  1160  may also be in communication with external processors or user input devices. In some embodiments, this may be by wireless connection via a network. The processor  1160  may also be in communication with an internal or external power source connected to the sonotrode transducer  1122 . The apparatus  1122  may also include a sensor package (not shown) mounted to the carriage housing  1112 . 
       FIGS.  19  and  20    illustrate a variation of the UAM system  1000  in which the lower portion of the frame  1241  is replaced by an extension and retraction arrangement  1900  that is configured to provide controllable radial movement of the carriage  1110  relative to the pipe centerline  25 . The arrangement  1900  may, in particular comprise a scissor jack, which has the advantage of producing a substantial linear force as the result of application of a relatively low rotational force. In ordinary jacks, the load applied to the jack is always compressive. Thus, when a load is applied to the top of a standard scissor jack, compressive forces are transmitted into the supports. These forces, in turn, produce a tensile load in the jack screw. 
     In certain embodiments of the present invention, however, the extension and retraction arrangement  1900  may be or include a particular type of scissor jack that is configured for both compression and tension loading. This type of jack is referred to herein as a bidirectional scissor jack. A bidirectional scissor jack usable in the present invention may include a number of support element structures, each formed from two elongate support elements pivotally attached to one another at their centers so that they form an X-shaped structure. In a typical embodiment, two of these X-shaped pairs of support elements are arranged in tandem. One support element of each pair has one end that is attached to the base of the jack by a fixed pivot while the other end is attached to a load platform by a pivot that is allowed to slide along a slot or rail formed in the platform support structure. The other support element has one end attached to the load platform by a fixed pivot while the other end is pivotally attached to a threaded block. The threaded block is configured to receive a threaded member referred to herein as a lead screw or jack screw. The lead screw for each pair engages a thrust bushing at one end. This bushing is fixedly attached to the base structure so that loads can be transmitted from the lead screw to the base structure through the bushing. The other end of the lead screw is coupled to the end of the lead screw associated with the other pair of support elements. The lead screw coupling may be configured so that it is attached or attachable to the base structure by a bearing that allows the coupling and the lead screws to rotate. 
     As noted above, one end of one of the support members of each pair is attached to a threaded block through which the lead screw passes. The pivot used to make this attachment may be configured to slidably engage a slot or rail formed in the base structure. Thus, when the lead screw is rotated, it causes the threaded block to translate along the base toward or away from the thrust bushing engaged by the lead screw. When the threaded block moves toward the thrust bushing, it takes the end of the attached support member with it. This causes the angle of the support member to steepen. By virtue of the central pivotal connection of the support members, the angle of the second member of the support element pair also steepens. The combined action of the support elements causes extension of the load platform. When the lead screw is turned in the opposite direction, the action is reversed and the load platform is retracted. 
     The tandem arrangement of the support element pairs allows both to be operatively connected to a single lead screw assembly having two oppositely threaded lead screw portions (one for each support pair). The tandem arrangement also provides an enhanced ability to transmit and counter both compressive and tensile loads. Under compressive loading, the two halves of the lead screw assembly are each placed in tension and push against one another through the lead screw coupling. Their outer ends are constrained by the thrust bushings. This is the response to a weight placed on the load platform in a manner similar to those applied to standard jacks. The bidirectional jack, however, is configured so that a load (e.g., the welding carriage  1110 ) may be attached to the load platform rather than merely resting on it. Under certain circumstances (e.g., the suspension of the welding carriage  1110  beneath the jack), such a load may apply a tensile load. In this scenario, each of the lead screw halves is placed in compression and is constrained by the thrust bushing and the lead screw coupling. 
       FIGS.  21 - 23    illustrate a particular jacking arrangement  1900  in the form of a bidirectional scissor jack configured as described above. The bidirectional jack  1900  has a base structure  1910  that can be attached to the frame  1241  and a load platform structure  1920  supported by four pairs of x-shaped support element structures. The load platform structure  1920  has a load support surface  1922  and may have connectors (not shown) for attaching the carriage  1110  to the support surface  1922 . Two of the x-shaped support element structures are positioned side-by-side on one side of the jack  1900  and, for convenience, are collectively referred to as the left support assembly  1930 , and two are positioned side-by side on the other side of the jack  1900  and are referred to as the right support assembly  1940 . The left support assembly  1930  has two elongate support members  1932   a ,  1932   b  forming the front left support structure visible in  FIGS.  21 ,  22  and  23   . The left support assembly  1930  also includes elongate support members  1934   a ,  1934   b , which are visible only in  FIG.  22   . The right support assembly  1940  has two elongate support members  1942   a ,  1942   b  forming the front right support structure visible in  FIGS.  21 ,  22  and  23   . The right support assembly  1940  also includes elongate support members  1944   a ,  1944   b , which are visible only in  FIG.  22   . 
     The left support members  1932   a ,  1932   b ,  1934   a ,  1934   b  are all connected by a pivot member  1933 . Front left support members  1932   a ,  1932   b  are paired as previously described as are back left support members  1934   a ,  1934   b . The right support members  1942   a ,  1942   b ,  1944   a ,  1944   b  are similarly connected by pivot member  1943 . The lower end of each of support members  1932   b  and  1934   b  are connected by pivot member  1935 , which is slidably connected to a rail assembly or slot  1924  of the load platform structure  1920 . The lower end of each of support members  1932   a  and  1934   a  are respectively pivotally connected to the load platform structure  1920  by a first pivot member  1937   a  and a second pivot member that is not shown. The upper end of support members  1932   b  and  1934   b  are respectively pivotally attached to the base structure  1910  by a first pivot member  1939   a  and a second pivot member  1939   b . The upper end of support member  1932   a  is pivotally attached to a threaded block  1938  by a pivot  1931 . The upper end of support member  1934   a  is similarly attached to the threaded block  1938  by a separate pivot that is not shown. The pivots used to attach the support members  1932   a ,  1934   a  to the threaded block  1938  may be configured so as to be slidably retained in a slot or rail assembly (not shown) of the base structure so as to constrain motion of the pivots to the horizontal direction (i.e., the direction along the length of the base). 
     It will be understood that right support members  1942   a ,  1942   b ,  1944   a ,  1944   b  are similarly mounted to the load platform structure  1920 , the base structure  1910 , and threaded block  1948  by corresponding pivot members  1945 ,  1949   a ,  1949   b ,  1945 ,  1941 . 
     The bidirectional jack  1900  includes a lead screw assembly  1950  that is made up of left and right lead screw portions  1952 ,  1954  joined by a lead screw coupling  1956 . The left lead screw portion  1952  is configured to threadably engage a threaded passage through the left threaded block  1938  and the right lead screw portion  1954  is configured to threadably engage a threaded passage through the right threaded block  1948 . In the illustrated embodiment, the left and right lead screw portions  1952 ,  1954  are oppositely threaded and that threaded blocks  1938 ,  1948  are arranged correspondingly. In alternative embodiments, the threads of the jack screw may all be in the same direction and one of the threaded blocks reversed. The lead screw coupling  1956  may be rotatably retained and supported by a bearing attached to a supporting wall  1916  extending across the width of the base structure  1910 . The outer ends of the left and right lead screw portions  1952 ,  1954  are rotatably attached to the base structure by thrust bearings  1953 ,  1955 . The thrust bearings  1952 ,  1954  are configured to transmit both compressive and tensile loads between the lead screw portions  1952 ,  1954  and the base structure  1910 . A drive shaft  1959  may be attached to either of the lead screw portions  1952 ,  1954  for use in selectively turning the lead screw assembly  1950  for raising or lowering the load platform  1920 . 
     Operation of the bidirectional jack  1900  is accomplished by manual or powered rotation of the of the lead screw assembly  1950 . Such rotation results in simultaneous extension or retraction of all four of the support structure pairs. Further compressive and tensile loading is distributed among all four structures for transmission to the base structure  1910 . 
     The bidirectional jack  1900  can be used to move the welding carriage  1110  radially inward or outward relative to the centerline  25  of the pipe segments  20 ,  30  to establish a desired distance from the surface or surfaces to which a weld is to be applied. The jack  1900  can also be used to supply a desired welding force to feedstock applied to the surface or surfaces to be welded. 
     In some in-the-field applications, pipe repair or joinder operations may involve pipe sections that are movable to some degree. In such applications, it may be desirable to have a welding apparatus that remains fixed during welding operation.  FIGS.  24 - 27    illustrate an exemplary scenario in which the welding target consists of two pipe sections  20 ,  30  similar to those used to illustrate the previous embodiment. In this case, however, the pipe sections  20 ,  30  are not fixed in place. 
     In this scenario, the pipe sections  20 ,  30  may be joined using an orbital UAM system according to another embodiment of the invention. This system takes the form of a welding apparatus  3000  a support fixture  3200  comprising two or more supports  3220  supported by a floor or other support surface  5  and configured to receive and rotatably support the pipe sections  20 ,  30  for joinder thereof. It will be understood that the fixture  3200  may also be used to receive a single pipe section for conducting a circumferential welding operation thereon. Each support  3220  of the support fixture  3200  has a drive assembly  3210  attached thereto. The drive assembly  3210  is configured to engage and support a guide collar assembly  3300  for supporting and selectively rotating the pipe sections  20 ,  30  (or the single pipe section) during a welding operation. The guide collar assemblies  3300   a ,  3300   b  may be substantially similar to the guide collar assemblies  1300   a ,  1300   b  of  FIGS.  12 - 18   . In some embodiments, however, the guide collar assemblies  1300   a ,  1300   b  may have gear racks on both sides. The drive assembly  3210  may be substantially similar to the drive arrangement  1210  if  FIGS.  16  and  17   . The primary difference between the drive arrangement  3210  and the previous drive arrangement  1210  is that the arrangements  3210  of the apparatus  3000  remain fixed and operation of the drive mechanisms result in rotation of the guide collar assemblies  3300   a ,  3300   b . In the illustrated embodiment, each drive arrangement  3210  has a first engagement portion  3212  for engaging the gear racks of one side of a guide collar assembly  3300  and a second engagement portion  3214  for engaging the gear racks of the other side of the guide collar assembly  3300 . 
     The guide collar assemblies  3300   a ,  3300   b  are attached to the pipe sections  20 ,  30  in a manner similar to that of the previous embodiment. The pipe sections  20 ,  30  are then positioned so that the guide collar assemblies  3300   a ,  3300   b  engage and are supported by the drive arrangements  3210  and the supports  3220 . 
     The welding apparatus  3000  also comprises a material deposition and welding carriage  3100  comprising a housing  3110  in which is disposed a weld head  3120  with a sonotrode  3120 . The carriage  3100  may be configured to receive weldable feedstock  3150  from a feedstock magazine  3151  mounted to the surface  5  or the support fixture  3200 . The magazine  3151  may comprise a reel or other source from which the weldable feedstock  3150  may be drawn. Alternatively, a feedstock source may be disposed within the housing  3110  in a manner similar to previously described embodiments. 
     The welding carriage  3100  is supported by a pair of beams  3230  mounted to the supports  3220  and a mounting arrangement  3240 . In some embodiments the mounting arrangement  3240  may include a rigid frame similar to the frame  1241  of  FIG.  18   . In other embodiments, such as the illustrated embodiment, the mounting arrangement  3240  includes a sleeved platform  3232  mounted to the beams  3230 . In some embodiments, the platform  3232  may be slidably mounted to the beams  3230  so that the carriage  3100  can move longitudinally along the beams  3230 . The carriage  3100  may be mounted to the platform  3232  by a jacking arrangement  3900  configured to allow the carriage  3100  to be selectively moved upward or downward (i.e., toward or away from the surface of a pipe or pipe segments mounted to the support system  3200 ). As in the previous embodiment, the jacking arrangement  3900  can also be used to supply a desired welding force to feedstock applied to the surface or surfaces to be welded. The jacking arrangement  3900  may be or comprise a scissor jack, which may, in particular, be a bidirectional scissor jack like that described above and shown in  FIGS.  21 - 23   . 
     In the illustrated embodiment, the welding carriage  3100  and its mounting arrangement  3240  are positioned between the supports  3220 . This positioning allows the material deposition and welding carriage  3100  to remain in place as pipe sections are rotatably placed in the support fixture  3200 . It will be understood, however, that the carriage  3100  may alternatively be configured for positioning after the pipe sections  20 ,  30  are in place. In a particular example, the carriage  3100  may be configured to be positioned on top of the pipe section(s) and to be held in place by an additional structure (not shown). 
     The carriage  3100  is configured so that the housing  3110  and the weld head/sonotrode  3120  remain fixed while the pipe sections  20 ,  30  are rotated. This produces a relative motion between the sonotrode  3120  and the interface  40  that is substantially the same as in the previously described orbital embodiment. As the pipe sections  20 ,  30  rotate in rotation direction R, feedstock  3150  is drawn from the feedstock source  352  to pass between the sonotrode  3120  and the surfaces of the pipe sections  20 ,  30  to produce a deposited/welded layer of feedstock material  3150 ′.  FIG.  28    shows the pipe sections  20 ,  30  at an initial position and  FIG.  29    shows the pipe sections  20 ,  30  after they have made a quarter of one rotation in direction R. (The guide member  3300   b  is removed from  FIGS.  28  and  29    for clarity.) The weld head  3120  is mounted so as to allow application of the welding force F W  to the feedstock  3150  and the structure surface during rotation of the pipe sections  20 ,  30  (or a single pipe section). The welding force F W  may be provided by the jacking arrangement  3900  or by other external electrical, mechanical or electromechanical mechanisms. In the illustrated embodiment, the weight of the pipe section(s) may contribute to the to the welding force F W . 
     At the same time the welding force W F  is being applied to the feedstock  3150 , the sonotrode transducer  3120  is energized to produce high frequency vibration to weld the feedstock  3150  to the structure (in this case, to the surfaces of the two pipe sections  20 ,  30 ). In the illustrated example, the welded feedstock layer  3150 ′ bridges the joint line  40  and serves as a first layer of an ultrasonic weld to permanently join the two pipe sections  20 ,  30 . Upon completion of one rotation, the carriage  3100  will have applied a complete first layer of welded feedstock  3150 ′. The pipe sections  20 ,  30  may simply continue their rotation to begin forming a second layer of welded feedstock  3150 ′. The process may be repeated as many times as necessary to produce a desired weld without removal or shifting of the carriage  3100  or the pipe sections  20 ,  30 . 
     If a complete circumferential weld layer is not required, the material deposition and welding carriage  3100  may be commanded to deposit and sonically weld a feedstock layer during only a portion of a rotation of a pipe section to target a particular circumferential area. Upon completion of deposition/welding of a layer over the target area, the rotation of the pipe section could be continued until the target area is again presented to the material deposition and welding carriage  3100 , whereupon a second layer could be initiated over the target area, and so on until a desired weld is achieved. 
     In some applications, it may be desirable to produce an over-lapping weld to enlarge the joining area along or adjacent the joint line  40 . In such applications, the pipe sections could be axially shifted after formation of an initial circumferential weld, and the process repeated to produce a second weld over-lapping the first. 
     As in the previous embodiment, the material deposition and welding carriage  3100  may also comprise an on-board data processor  360  in communication with the sonotrode transducer  3120  and feedstock dispensing mechanism. The processor  360  may also be in communication with external processors or user input devices. In some embodiments, this may be by wireless connection via a network. The processor  360  may also be in communication with an internal or external power source connected to the sonotrode transducer  3120 . The apparatus  3120  may also include a sensor package (not shown) mounted to the carriage housing  3110 . The sensor package may be in communication with a data processor and could include, for example, optical, laser, thermal or other sensors configured and positioned to capture data on the applied feedstock  3150 ′. The captured data may be analyzed to assess the integrity of the welded layer  3150 ′. 
     Aspects of the present invention can also be applied in planar repair or manufacturing processes. In an illustrative scenario shown in  FIGS.  30 - 36   , a thin plate  60  is to be welded to a large vertically oriented wall or base plate  50  along an interface line  40 . For this application, a planar motion portable welding apparatus  4000  according to an embodiment of the invention may be used for in-situ welding. As schematically illustrated in  FIGS.  30 - 36   , the welding apparatus  4000  comprises a material deposition and welding carriage  4100  attached to and supported by a planar motion fixture  4700 . The fixture  4700  is similar in concept and operation to an xy-plotter in that it allows controlled two dimensional movement of the carriage  4100  parallel to a generally planar surface to which the fixture  4700  is attached. 
     The fixture  4700  comprises a rectangular outer frame  4710  with two horizontal guide rails  4780  and two vertical guide rails  4790  and a support  4770  at each corner. The supports  4770  are configured for removable attachment to the planar wall  50 . The supports may be attached using any mechanism sufficient to counter the forces applied to the wall  50  during a welding operation. Suitable mechanisms may include, without limitation, tack welding, reversible chemical or thermal bonding, hydraulics, mechanical fasteners (e.g., screws, bolts, clamps, etc.), and magnets. The fixture  4700  is configured for operably retaining a carriage support arrangement that comprises a horizontal (x axis) beam  4720  movably mounted to the vertical guide rails  4790  and a vertical (y axis) beam  4740  movably mounted to the guide horizontal guide rails  4780 . The attachments of the beams  4720 ,  4740  to the guide rails  4780 ,  4790  are configured so that the beams can be moved in directions orthogonal to their respective longitudinal axes  4730 ,  4750 . The beams  4720 ,  4740  may be formed from solid or tubular members or from channel stock. While in the illustrated embodiment, the beams  4720 ,  4740  have a rectangular cross-section, other polygonal or round (e.g., circular) cross-sections may be used. 
     The horizontal beam  4720  may be mounted to the vertical guide rails  4790  by a pair of guide rail followers  4792  configured to slide vertically along the guide rails  4790 . Similarly, the vertical beam  4740  may be mounted to the horizontal guide rails  4780  by a pair of guide rail followers  4782 . In some embodiments, the guide rail followers  4782 ,  4792  may be provided with an automated or manual drive mechanism configured to selectively translate the beams  4720 ,  4740  along their respective guide rails  4790 ,  4780 . Some such embodiments may include a geared drive mechanism such as in the exemplary arrangement shown in  FIGS.  33   a  and  33   b   . In this arrangement, the vertical guide rail  4790  is formed with a channel  4712  on its outward facing side. Within this channel is positioned a linear gear rack  4714 . The guide rail follower  4792  is attached to the end of the horizontal beam  4720 . A drive gear  4794  mounted to a gear shaft  4795  inside the follower  4792  is configured to operably engage the gear rack  4714  so that rotation of the drive gear  4794  causes the guide rail follower  4792  to move along the guide rail  4790 . The gear shaft  4795  may extend out through the case of the guide rail follower  4792  so that it can be engaged by any form of rotational power mechanism (not shown). Alternatively, a manually rotatable wheel can be attached to the drive shaft  4795 . It will be understood that such a drive gear mechanism may be provided for guide rail followers  4792  attached at the ends of the horizontal beam  4720 . It will further be understood that a similar drive gear arrangement may be provided for one or both of the followers  4782  attached to the ends of the vertical beam  4740 . 
     In embodiments, having powered drive mechanisms for the rail followers  4782 ,  4792 , such drive mechanisms may be controlled by a wired or wireless motion control processor. The motion control processor may be configured to receive motion commands from a user and transmit them to the drive mechanisms to provide control over the translational motion of the horizontal and vertical beams  4782 ,  4792  and, thus, the path of the carriage  4100 . The motion control processor may be configurable to provide a sequence of instructions to the first and second movement control mechanisms configured to cause the movement of the carriage  4100  along a predetermined two-dimensional path. 
     The material deposition and welding carriage  4100  may be substantially similar to that of the weld carriage  110  of  FIGS.  1 - 3   , but without the undercarriage. Similar to the weld carriage  110 , the carriage  4100  has a carriage housing  4300  with a sonotrode  4200  and an arrangement  4520  for dispensing feedstock material  4500  and applying it to a target surface. In some embodiments, it may be beneficial to eliminate the housing  4300  and directly couple the sonotrode  4200  to the jacking arrangement  4900 . 
     The material deposition and welding carriage  4100  is mounted to the planar motion fixture  4700  and a mounting arrangement  4240  that includes the horizontal and vertical beams  4720 ,  4740 , a follower body  4400 , and a jacking arrangement  4900 . The follower body  4400  may be solid or hollow, but in either case is configured to slidably receive both the horizontal beam  4720  and the vertical beam  4740  so that the follower body  4400  can slide along either beam  4720 ,  4740  when the other beam  4720 ,  4740  is moved along its respective guide rails  4790 ,  4780 . Accordingly, the mounting arrangement  4240  and the carriage  4100  are moved when the beams  4720 ,  4740  are moved along the guide rails  4780 ,  4790 . When the horizontal beam  4730  moves, the carriage  4100  is moved in a direction parallel to the y-axis  4750  and when the vertical beam  4740  moves, the carriage  4100  is moved in a direction parallel to the x-axis  4730 . In this way, the carriage  4100  may be moved along any path within a plane parallel to the wall  50 . In some embodiments, one or more handles  4180  may be attached to the follower body  4400  to facilitate manual movement of the carriage  4100 . As previously described, in some embodiments, movement of the carriage may be accomplished by mechanized movement of the beams  4720 ,  4740  along the guide rails  4780 ,  4790 . 
     The carriage  4100  is attached to the follower body  4400  by the jacking arrangement  4900  so that the carriage  4100  may be extended or retracted along a z-axis  4110  orthogonal to the x-axis  4730  and the y-axis  4750  (i.e., toward or away from the target surface). The jacking arrangement  4900  may be substantially similar to those of the previously described embodiments. As best seen in  FIG.  32   , the base member  4910  of the jacking arrangement  4900  is attached to the follower body  4400  while the extendible and retractable load platform  4920  of the jacking arrangement  4900  is attached to the carriage housing  4300 . 
     It will be understood that in some embodiments, the jacking arrangement  4900  may be replaced by a rigid structure tow which the carriage housing  4300  is attached. This structure may be sized and configured to place the sonotrode  4200  in close proximity to or in contact with the target surface. In other embodiments, the carriage housing  4300  may be attached directly to the follower body  4400 . 
     The carriage  4100  is configured so that when the fixture  4700  is mounted to the wall  50 , the sonotrode  4200  may be selectively brought near to or into contact with the surface of the wall  50  by extending the jacking mechanism  4900 . While in contact, the sonotrode  4200  may slide along the surface as the carriage  4100  is moved along the horizontal and/or vertical beams  4720 ,  4740 . In the embodiment and scenario illustrated in  FIGS.  34 - 36   , the carriage  4100  is mounted so that the feedstock  4500  can be laid along the interface line  40 , which parallel to the vertical beam  4740 . It will be understood that the apparatus can be mounted so as to lay and weld feedstock a long a line parallel to the horizontal beam  4720  as well. In some embodiments, the carriage  4100  may be configured to be rotatable so that remounting is not necessary and so that feedstock  4500  may be deposited and welded along any two dimensional path. Regardless of its path, as the carriage  4100  moves in a forward direction D, feedstock  4500  may be selectively drawn from the feedstock source  4520  to pass between the sonotrode  4200  and the surface of the structure(s) to be welded. 
     It will be understood that in some embodiments or applications, movement of the carriage  4100  is accomplished manually. In other embodiments, the motion of the carriage  4100  may be accomplished through powered drive mechanisms on board the rail followers  4782 ,  4792 , which may, in turn, be either automated or manually controlled. 
     As in the previous embodiment, the material deposition and welding carriage  4100  may comprise an on-board data processor  4600  in communication with the sonotrode transducer and feedstock dispensing mechanism  4520 . The processor  4600  may also be in communication with external processors or user input devices. In some embodiments, this may be by wireless connection via a network. 
     The processor  4600  may also be in communication with an internal or external power source connected to the sonotrode  4200 . A sensor package  4620  may be mounted within the weld head carrier  4300 . The sensor package  4620  may be in communication with the data processor  460  and could include, for example, optical, laser, thermal or other sensors configured and positioned to capture data on the applied feedstock  4500 ′. The captured data may be analyzed to assess the integrity of the welded layer  4500 ′. 
       FIGS.  34 - 36    illustrate a sequence of operation for the welding apparatus  4000 . In  FIG.  34   , the guide rails  4780 ,  4790  of the frame  4700  are mounted to the wall  50  so that the interface  40  to be welded is within the outer frame  4700 . The carriage  4100  and beams  4720 ,  4740  are mounted to the guide rails  4780 ,  4790 . As shown in  FIG.  34   , the carriage  4100  may initially be positioned away from the target area.  FIG.  35    shows the carriage  4100  after movement in the horizontal and vertical directions to a position at one end of the interface  40  where welding is to be initiated.  FIG.  35    also shows that the jacking mechanism  4900  has been extended to bring the sonotrode  4200  into contact with the surface  50 . Starting from this position and configuration, a welding operation is conducted in which the carriage  4100  is moved over or along the interface line  40 . As the carriage  4100  moves feedstock material  4500  is deposited on the target surface ahead of the sonotrode  4200 . As the sonotrode  4200  engages the deposited feedstock material, the sonotrode  4200  applies a welding force F W  is applied and ultrasonic vibrations are conducted into the feedstock material and the target surface along the Z-axis Z-axis  4110  thereby producing a welded feedstock material  4500 ′.  FIG.  36    shows the carriage  4100  in a position partway along the interface  40 , a layer of welded feedstock  4500 ′ having been disposed over and welded to the plate  60  and the wall  50  on both sides of the traveled portion of the interface  40 . 
     Upon completion of its path along the interface  40 , the carriage  4100  will have applied a complete first layer of welded feedstock  450 ′. The carriage  4100  may then be returned to the position shown in  FIG.  35    and the feedstock deposition and welding action repeated for another layer of feedstock  450 ′ following the same carriage path. The process may be repeated as many times as necessary to produce a desired weld. 
     In some applications, it may be desirable to produce an over-lapping weld to enlarge the weld area. In such applications, after formation of an initial weld along a first carriage path, a second weld over-lapping the first may be formed by passing the carriage along a second path shifted slightly from the first. 
     In any of the foregoing embodiments, the material deposition and welding apparatus may include hardware for conducting a machining operation (i.e., a material removal or shaping action). In particular, CNC machining may be used prior to performing the deposition/welding operation (e.g., surface preparation) or following the deposition/welding operation (e.g., to remove material added via the process). 
     In the methods of the invention, the sonotrode frequency, speed, and force are parameters that may be controlled by either user input or feedback from a closed loop control system. An open-looped control system could also be utilized but may require additional manual operations to apply forces locally via mechanical means. Control parameters may be pre-programmed or changed during the deposition by closed loop control based on in situ measurements obtained from an array of sensors. 
     This system and method can integrate laser scanning in-situ for dimensional monitoring or deposition quality. In this proposed variant in-situ scanning could be used to scan the material in question as part of manual or closed loop controls to inform the deposition process and manually or automatically adjust the deposition of material. It is also understood that a system of integrated or individual sensors may be used for the deposition of the material using one or more of the following measurements:
         1. Thermal measurement can be performed on the base material and applied material via thermal imaging or temperature readings for quality control.   2. Measurement of acoustic or other ultrasonic readings to enable the devices monitoring.   3. Visual dimensional measurements can be made to manually or automatically to adjust the application and may use a plurality of cameras, imaging hardware/software, infrared, or other suitable optical measurements for determining material position for both the base material and feedstock.   4. Integrated use of magneto-induction complex impedance analysis, eddy current, acoustic measurement, and/or other electro-magnetic properties may be integrated into this system to inspect, measure, or otherwise provide objective quality evidence of the material before, during, or after fabrication.   5. Part scanning for fabrication, path planning, and post inspection are considered integral variants of this method.       

     Application of the device can be performed manually or automatically with path planning or similar software for the automatic fabrication or repair of material or components. Path planning may be modified in-situ based on readings from one or more sensors monitoring the material deposition. 
     The systems and methods of the invention have many applications, including, but not limited to, the following: joining of materials, pipe, repair of pipe or pipe joints, repair of flat surfaces (e.g., bulkheads), and cladding of pre-shaped feedstock to flat surface or pipe. However, it should be understood that this method is not constrained to just those examples. Essentially any material (or even dissimilar metals) may be joined methods of the invention. If an ultrasonic bond can be made between the feedstock and the base structure/material, then it expected that this system and method can be applied. 
     It will be understood that the above method may incorporate diagnostic operations to assess the condition/characteristics of a weld after application of a weld layer. Information from these diagnostic operation may be used to make adjustments to the welding apparatus or operation. 
     It will be understood that the methods of the invention may be used in conjunction with any form of ultrasonic weld process using any suitable material. Further, it will be readily understood by those persons skilled in the art that the present invention is susceptible to broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and foregoing description thereof, without departing from the substance or scope of the invention.