Patent Publication Number: US-2013248496-A1

Title: Precision ribbon resistance welding system

Description:
FIELD OF THE INVENTION 
     Aspects of the present invention relate to systems and methods for manufacturing. More specifically, the present invention relates to systems and methods for resistance welding electrical connections between electrical components of implantable medical pulse generators. 
     BACKGROUND OF THE INVENTION 
     Implantable medical pulse generators such as, for example, pacemakers and implantable cardioverter defibrillators (ICDs), contain various electrical components that are electrically connected together. Currently, a variety of connection methods are employed to electrically connect together the electrical components of a first type of pulse generator, while a different variety of connection methods may be employed for another type of pulse generator. Examples of connection methods include soldering, wire bonding, connectors, etc. The electrical connections between the various electrical components must be robust and capable of being achieved efficiently and economically. 
     There is a need in the art for systems and methods of achieving electrical connections within an implantable medical pulse generator that are more robust and economical. Further, there is a need in the art for systems and methods of achieving electrical connections within an implantable medical pulse generator, wherein the systems and methods are more commonly applicable across a wider variety of pulse generators and electrical components within pulse generators. In other words, there is a need in the art for a method of achieving electrical connections within an implantable medical pulse generator that will work for all types of pulse generators and all types of electrical connections within the pulse generators. 
     BRIEF SUMMARY OF THE INVENTION 
     Disclosed herein is a resistance welding system for welding a ribbon to a bond site of a bond surface. In one embodiment, the system includes a welding header, a bond header, a ribbon dispenser, a cutter, and a support surface. The welding header includes a resistance welding tip. The bond header includes a bond foot displaceable relative to the bond surface. The bond foot includes a welding aperture. The ribbon dispenser feeds the ribbon to the bond foot. The cutter is near the bond foot. The support surface is configured to support the bond surface. The bond foot is configured to press the ribbon against the bond site of the bond surface, which is thereby forced against the support surface. With the ribbon so pressed against the bond site, the system is configured to cause the welding tip to enter the welding aperture to resistance weld the ribbon to the bond site of the bond surface. The system also configured to then move the bond foot to a location adjacent the bond site and cause the cutter to sever the ribbon at a location between the bond foot and the bond site. 
     Also disclosed herein is a method of connecting electrical components of an implantable medical pulse generator during the course of manufacturing the implantable medical pulse generator. In one embodiment, the method includes: a) supporting an electrical component on a support surface of a resistance welding system; b) feeding a ribbon between a bond foot of the resistance welding system and a bond site of a bond surface of the electrical component; c) causing the bond foot to press the ribbon against the bond site of the bond surface, thereby forcing the electrical component against the support surface; d) with the bond foot pressed against the ribbon as recited in step c), causing a resistance welding tip to enter a welding aperture of the bond foot; e) causing the resistance welding tip to resistance weld the ribbon to the bond site of the bond surface within the confines of the aperture; f) causing the bond foot to displace to a location adjacent the a weld resulting from step e); and g) using a cutter to sever the ribbon between the weld and the location adjacent the weld. 
     While multiple embodiments are disclosed, still other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the disclosure. As will be realized, the invention is capable of modifications in various aspects, all without departing from the spirit and scope of the present disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating an embodiment of a precision ribbon resistance welding system. 
         FIG. 2  is an isometric view of the bond header and welding header positioned nearby, wherein the bond header is configured to allow the welding header to enter the bond header laterally. 
         FIG. 2A  is an isometric view of the bond header and welding header positioned nearby, wherein the bond header is configured to allow the welding header to enter the bond header vertically. 
         FIG. 3  is an enlarged isometric view of a first embodiment of the bond foot with the welding header positioned nearby, wherein the bond header is configured to allow the welding header to enter the bond header laterally. 
         FIG. 4  is a bottom plan view of the bond foot of  FIG. 3 . 
         FIGS. 5 and 6  are the same respective views as  FIGS. 3 and 4 , except of another embodiment. 
         FIG. 7  is an enlarged isometric view of another embodiment of the bond foot with the welding header positioned nearby, wherein the bond header is configured to allow the welding header to enter the bond header vertically. 
         FIGS. 8 and 9  are, respectively, a side elevation view and a side elevation cross sectional view of the embodiment of the bond foot depicted in  FIGS. 3 and 4 . 
         FIG. 10  is the same view as  FIG. 8 , except the ribbon has been welded to the first bond site and the bond header is displacing to a second bond site. 
         FIG. 11  is the same view as  FIG. 8 , except the bond header and welding tip are at the second bond site and welding the ribbon to the second bond site. 
         FIG. 12  is the same view as  FIG. 8 , except the bond header is moving away from the completed welding of the ribbon to the second bond site. 
         FIG. 13  is a view similar to that of  FIG. 12 , except the bond header has moved to a location adjacent the second bond site and the ribbon is being severed via a cutter. 
     
    
    
     DETAILED DESCRIPTION 
     Implementations of the present disclosure involve a precision ribbon resistance welding system  10  and methods of resistance welding with such a system. The system  10  is useful in making precise electrical connection between electrical circuits and components of electronic devices such as implantable pulse generators such as, for example, pacemakers and implantable cardioverter defibrillators (ICDs). 
       FIG. 1  is a diagram illustrating an embodiment of a precision ribbon resistance welding system  10  disclosed herein. As shown in  FIG. 1 , the system  10  includes a ribbon assembly  15 , a support surface  17 , and a welding assembly  20 . The two assemblies  15 ,  20  may be supported of off separate support structures or may share the same support structure but be independently moveable relative to each other. Specifically, in one embodiment, the resistance welding assembly  20  is stationary or fixed, the support surface  17  and ribbon assembly  15  are moveable relative to each other, and the support surface  17  and ribbon assembly  15  are moveable as a unit relative to the welding assembly  20 . 
     The ribbon assembly  15  may include a spool  25  on which a ribbon  30  is rolled off of when dispensed from the spool  25  through the ribbon assembly. The ribbon assembly  15  also includes a bond arm  35  that supports a bond header  40  and a ribbon clamp  45 . The ribbon  30  extends from the spool  25  down through the ribbon clamp  45  and along or through the bond header  40  to a bond foot  50  at a bottom end of the bond header  40 . The bond foot  50  is positioned over a bond site  55  of a bond surface  60 , which may be a location on a circuit board, ICD hybrid, or other electrical circuit element that is to be electrically connected to another electrical circuit element via the system  10 . The ribbon assembly  15  is configured so as to allow the bond foot  50  to be moved in a controlled and precise manner from bond site  55  to bond site as electrical circuit elements are electrically coupled to each other via welding of a first end of a segment of ribbon  30  to a first bond site of a first electrical circuit element and welding of a second end of a segment of ribbon  30  to a second bond site of a second electrical circuit element. 
     The support surface  17  may be in the form of a platform or table on which bond surface  60  may be supported and secured. Thus, if the support surface  17  moves, the bond surface  60  will likewise move with the support surface  17 . 
     The welding assembly  20  may include a welding arm  65  that supports a welding header  70 . In one embodiment, the welding assembly  20  or at least the welding arm  65  is configured so as to allow the welding header  70  and, more specifically, a resistance welding tip  75  of the welding header  70  to move into and out of the bond foot  50 , as discussed in detail below. Because in one embodiment the resistance welding tip  75  is fixed and non-displaceable, as discussed in detail below, the movement of the welding tip  75  into and out of the bond foot  50  is accomplished via movement of the bond foot  50  and support surface  17  as a unit relative to the welding tip  75 . 
     In another embodiment, as discussed below, the resistance welding tip  75  is configured to move with the bond foot  50  laterally as a unit. The welding tip  75  displaces vertically into and out of the bond foot  50 . 
     As illustrated in  FIG. 1 , a cutter  76  is supported off of the bond header  40 . The cutter  76  has a cutting edge  77  that moves vertically to sever the ribbon  30  as discussed in detail below. 
     As shown in  FIG. 2 , which is an isometric view of the bond header  40  and welding header  70  positioned nearby, the bond header includes an elongated body  80  that extends down to the bond foot  50 . A welding aperture  85  is defined in the bond foot, and the welding tip  75  of the welding header  70  is positioned to the side of the bond foot  50  so as to be able to enter the welding aperture  85  via movement of the bond foot  50  and support surface  17  as a unit relative to the welding tip  75 . Alternatively, as illustrated in  FIG. 2A , the welding header  70  may be centered over the welding aperture  85  and configured to move with the welding header  70  as a unit such that when the welding header is positioned at a location where a weld is to be made, the welding header  70  may simply displace vertically to enter the welding aperture  85  to create the weld. 
     As illustrated in  FIG. 3 , which is an enlarged isometric view of a first embodiment of the bond foot  50  with the welding header  70  positioned nearby, the bond foot includes a front or toe  90 , a back or heal  95  opposite the toe  90 , and lateral sides  100  extending between the heal  95  and toe  90 . The bond foot  50  also includes a top surface  105 , a bottom surface  110  with an arch  115  defined in the bottom surface near the heal  95 , and a welding aperture  85  that extends vertically through the bond foot  50  from the top surface  105  to the bottom surface  110 . The welding aperture  85  is generally centered in the top surface  105  and substantially circular or, in other embodiments, of other shapes, such as, for example, square, rectangular, oval, etc. A welding access slot  120  extends through the toe  90  to join the welding aperture  85 . The slot  120  is sized such that the resistance welding tip  75 , which has dual electrodes, may pass into the welding aperture  85  to assume a position within the welding aperture  85  to perform a weld as described below. 
     As depicted in  FIG. 4 , which is a bottom plan view of the bond foot  50  of  FIG. 3 , the welding aperture  85  is generally centered in the bottom surface  110  and substantially circular or, in other embodiments, of other shapes, such as, for example, square, rectangular, oval, etc. A ribbon threading slot  105  is supported on the bond foot  50  above the heal  95 . The ribbon threading slot  105  has a threading slot entrance  105   a  into which the ribbon  30  (see  FIG. 1 ) can enter from the back of the bond head  100 . The threading slot  105  also has a threading slot exit  105   b  from which the ribbon  30  may exit while the ribbon is being spooled out in connection with loop formation, described below. 
     As indicated by arrow A in  FIGS. 3 and 4 , the bond header  40  may displace generally, exclusively, horizontally so as to cause the resistance welding tip  75  to pass through the wall of the toe  90  via the welding access slot  120  into the welding aperture  85 . In one embodiment, the welding aperture  85  has a diameter of between approximately 0.035″ and approximately 0.04″, the welding tip  75  with its dual electrodes has a width of between approximately 0.015″ and approximately 0.02″, and the welding access slot  120  has a diameter of between approximately 0.025″ and approximately 0.03″. 
     While the embodiment depicted in  FIGS. 3 and 4  illustrates the welding access slot  120  extending through the toe  90  to join the welding aperture  85 , in other embodiments, the welding access slot may extend through other sides of the bond foot  50  to join the welding aperture. For example, as illustrated in  FIGS. 5 and 6 , which are the same respective views as  FIGS. 3 and 4 , except of another embodiment, the welding access slot  120  extends through one of the lateral sides  100  of the bond foot  50  to join the welding aperture  85 . 
     In yet other embodiments, as depicted in  FIG. 7 , the toe  90  does not include an access slot  120 . Instead, the welding header  70  is centered over the welding aperture  85  and configured to move with the welding header  70  as a unit. When the welding header is positioned at a location where a weld is to be made, the welding header  70  displaces vertically as indicated by arrow A in  FIG. 7  to enter the welding aperture  85  to create the weld. 
       FIGS. 8 and 9  are, respectively, a side elevation view and a side elevation cross sectional view of the embodiment of the bond foot  50  depicted in  FIGS. 3 and 4 . As can be understood from  FIGS. 1 ,  3 ,  4 ,  8  and  9 , the ribbon  30 , which is a conductive metal ribbon, is supplied on a standard spool  25  and extended down to thread through the threading slot  105  of the bond header  40  to extend along the bottom surface  110  of the bond foot  50 . The threading slot  105  is preferably adapted to admit ribbons of various thicknesses, e.g., 1 mil. 
     As indicated in  FIGS. 8 and 9 , the bond header  40  descends to the bond surface  60  and forces the ribbon  30  to contact the bond surface of the substrate or component to be bonded, e.g., a printed circuit board or hybrid bond pad supported on the support surface  17 . In one embodiment as can be understood from the embodiments depicted in  FIGS. 3-6 , once a predetermined load is applied to the ribbon  30  sandwiched between the bottom surface  110  (shown in  FIGS. 3 and 4 ) of the bond foot  50  and the bond surface  60 , the sandwiched and compressed assembly of the bond foot  50 , ribbon  30 , bond surface  60  and support surface  17  move as a unit such that the resistance welding tip  75  is caused to enter into the confines of the welding aperture  85  via the access slot  120 . Thus, the entry of the welding tip  75  into the aperture  85  is brought about by the bond header  40  and work platform  17  supporting the bond surface  60  and ribbon  30  moving as a unit to the location of the fixed, stationary welding tip  75 . 
     Alternatively for the process depicted in  FIGS. 8 and 9 , as can be understood from the embodiment depicted in  FIG. 7 , the bond foot  50  and welding header  70  move as a unit. The bond foot  50  applies a predetermined load to the ribbon  30 , which is sandwiched between the bottom surface  110  of the bond foot  50  and the bond surface  60 . With the ribbon so sandwiched, the resistance welding tip  75  is caused to enter into the confines of the welding aperture  85  via vertical displacement of the welding tip into the welding aperture, as indicated by arrow A in  FIG. 7 . 
     With the bottom surface  110  of the bond foot  50  pressing the ribbon  30  against the bond surface  60  at the bond site  55  and the resistance welding tip  75  having entered the welding aperture  85 , the welding tip  75  can be brought into brief contact with the ribbon  30  located within the confines of the welding aperture  85 . As a result, current flows as the dual electrodes of the welding tip  75  touches the ribbon  30 , thereby causing resistance welding of the ribbon  30  located with the confines of the welding aperture  85  to the bond surface  60  at the bond site  55 . 
     As illustrated in  FIG. 10  and as can be understood from  FIG. 1 , once a first end of the ribbon  30  is resistance welded to a first bond site  55  (indicated by arrow B in  FIG. 10 ) as described above with respect to  FIGS. 8 and 9 , in the embodiment depicted in  FIGS. 3 and 5 , the resistance welding tip  75  exits the welding aperture  85  via the access slot  120  and on account of movement as a unit relative to the fixed and stationary welding tip  75  of the bond header  40  and work platform  17  supporting the bond surface  60  and ribbon  30 . The bond header  40  then steps (e.g., lifts up and moves horizontally or laterally) to a second bond site  55  (indicated by arrow C in  FIG. 10 ). In displacing from the first bond side to the second bond site, the spool  25  is free to spool out the ribbon  30 , resulting in a ribbon segment  118  extending between the first and second bond sites. 
     As can be understood from  FIG. 10 , in the embodiment depicted in  FIG. 7 , the resistance welding tip  75  exits the welding aperture  85  via vertical displacement. The bond header  40  and welding header  70  then steps (e.g., lifts up and moves horizontally or laterally) to a second bond site  55  (indicated by arrow C in  FIG. 10 ). In displacing from the first bond side to the second bond site, the spool  25  is free to spool out the ribbon  30 , resulting in a ribbon segment  118  extending between the first and second bond sites. 
     As shown in  FIG. 11 , once the bond header has stepped to the second bond site  55 , the bond header  40  descends to the bond surface  60  and forces the ribbon  30  to contact the bond surface of the substrate or component to be bonded, e.g., a printed circuit board or hybrid bond pad supported on the support surface  17 . In one embodiment as can be understood from the embodiments depicted in  FIGS. 3-6 , once a predetermined load is applied to the ribbon  30  sandwiched between the bottom surface  110  (shown in  FIGS. 3 and 4 ) of the bond foot  50  and the bond surface  60 , the sandwiched and compressed assembly of the bond foot  50 , ribbon  30 , bond surface  60  and support surface  17  move as a unit such that the resistance welding tip  75  is caused to enter into the confines of the welding aperture  85  via the access slot  120 . Thus, the entry of the welding tip  75  into the aperture  85  is brought about by the bond header  40  and work platform  17  supporting the bond surface  60  and ribbon  30  moving as a unit to the location of the fixed, stationary welding tip  75 . 
     Alternatively for the process depicted in  FIG. 11 , as can be understood from the embodiment depicted in  FIG. 7 , the bond foot  50  and welding header  70  move as a unit. The bond foot  50  applies a predetermined load to the ribbon  30 , which is sandwiched between the bottom surface  110  of the bond foot  50  and the bond surface  60 . With the ribbon so sandwiched, the resistance welding tip  75  is caused to enter into the confines of the welding aperture  85  via vertical displacement of the welding tip into the welding aperture, as indicated by arrow A in  FIG. 7 . 
     With the bottom surface  110  of the bond foot  50  pressing the ribbon  30  against the bond surface  60  at the second bond site  55  and the resistance welding tip  75  having entered the welding aperture  85 , the welding tip  75  can be brought into brief contact with the ribbon  30  located within the confines of the welding aperture  85 . As a result, current flows as the welding tip  75  touches the ribbon  30 , thereby causing resistance welding of the ribbon  30  located with the confines of the welding aperture  85  to the bond surface  60  at the second bond site  55 . 
     As indicated in  FIG. 12  and as can be understood from  FIG. 1 , once a second end of the ribbon  30  is resistance welded to a second bond site  55  (indicated by arrow C in  FIG. 12 ) as described above with respect to  FIG. 11 , the resistance welding tip  75  exits the welding aperture  85  via one of the methods described above with respect to  FIG. 3 ,  5  or  7 . The bond header  40  then steps (e.g., lifts up and moves horizontally or laterally) to another location such as, for example, yet another bond site or to a location (shown by arrow D in  FIG. 13 ) immediately adjacent the second bond site indicated by arrow C in  FIGS. 12 and 13 . In making this move, the spool  25  is allowed to rotate, thereby allowing the ribbon  30  to be pulled from the spool  25  down through the threading slot  105  and across the bottom surface  110  of the bond foot  50 . The bond foot sandwiches the ribbon against the bond surface  60  at the adjacent site called out by arrow D. With the ribbon so sandwiched, the cutter  76  is vertically displaced to sever the ribbon at the front face of the bond foot. As a result, the ribbon is pre-fed across the bottom surface of the bond foot and the bond header can then move to a new bond location to begin the bonding process over again as set out above with respect to  FIGS. 8-13 . 
     In one embodiment, a cutter  76  is not employed to terminate the ribbon  30 . For example, in displacing from the second bond side to another location, the spool  25  is prevented from spooling out the ribbon  30 , thereby causing the ribbon to break near the heal  95  of the bond foot  50 . Specifically, the ribbon clamp  45  clamps down on the ribbon  30  between the spool  25  and the heal  95  to prevent the ribbon  30  from being spooled out further from the spool. The subsequent stepping of the bond header  40  to another location causes the ribbon to fracture at or near the heal  95 . As a result, a ribbon segment  118  extends between the first and second bond sites, a first end of the ribbon segment being welded to the first bond site and a second end of the ribbon being welded to the second bond site. 
     With the ribbon segment  118  welded to the first and second bond sites and the ribbon  30  having been broken off at approximately the heal  95  of the bond foot  50 , the spool  25  can feed the ribbon along the bond surface  60  of the bond foot  50  as the bond header  40  moves to yet another location and in anticipation of repeating the welding operation described above with respect to  FIGS. 8 ,  9  and  11 . 
     As can be understood from  FIGS. 8-13 , depending on the embodiment of the welding system  10 , the bond header  40  and/or support surface  17  have several axes or modes of travel, for example, along an x-axis, y-axis, z-axis (vertically), and theta (rotation). Also, depending on the embodiment, the bond header  40  may be moveable relative to a stationary support surface, the support surface moveable relative to a stationary bond header, or the bond header and support surface  17  are both independently moveable relative to each other, but also moveable as a unit together. By these various modes of travel as shown in  FIGS. 8-13  and, further, by the bond header  40  moving independently from the support surface  17 , or vice versa, the bond header  40  may be positioned at a first bond site  55  (indicated by arrow B) upon the bond surface  60  supported by the support surface  17 . Once being appropriately positioned at the first bond site with respect to the x-axis, the y-axis and theta (rotation), the bond header  40  then descends (or the support surface  17  rises) along the z-axis in order to contact the ribbon  30  to the bond surface  60 . The ribbon  30  is therefore disposed between the bond foot  50 , the bond surface  60  and the support surface  17 , and thereby held in place. 
     With respect to movement of the bond head  40  from a first bond site  55  to a second bond site  55 , such bond head motion may be a relative motion only with regard to the work piece containing bond sites, a work table, or the like. In other words, what is generally termed the bond head motion may be one of or a combination of head, table or work piece movements vis-a-vis each other. 
     As discussed above with respect to  FIG. 10 , in one embodiment, while the weld between the ribbon  30  and the bond surface  60  at the first bond site  55  is cooling, the bond header  40  may move to the second bond site  55 . Such a move between bond sites  55  may be programmed in a memory of the system  10  and caused to be via an operation of a CPU of the system  10 . Thus, such a move between bond sites may be through an automated or otherwise predetermined trajectory adapted to spool out from the bond header  40  a desired length of ribbon  30  to form a ribbon segment  118 . 
     The ribbon  30  is fed from the spool through the bond tool ribbon threading slot  105 , which holds the ribbon  30  in place during both bonding and displacement of the bond header. The ribbon  30  may freely pass through the ribbon threading slot  105  while the bond header  40  travels between the first and second bond sites  55  (shown at arrows B and C, respectively) or between subsequent bond sites or welds. 
     As discussed above with respect to  FIG. 11 , upon contact with a second bond site  55 , the ribbon  30  is again disposed between the bond foot  50  and bond surface  60  of the second bond site  55 . The welding tip  75  is again located within the welding aperture  85  to form a weld between the ribbon and the bond surface of the second bond site. Thereafter, further ribbon  30  may be spooled out from ribbon spool  25  in order to form a connected second loop from a continuous length of ribbon. Further movement to an immediately adjacent location followed by severing of the ribbon via the cutter  76  results in the ribbon being pre-fed or loaded across the bond foot, as described above with respect to  FIGS. 12 and 13 . Such operation is advantageous in that it provides positive feeding of the ribbon across the bottom surface of the bond foot and results in the ribbon tending to conform to the surfaces of the bond foot across which the ribbon extends. 
     Alternatively, as discussed above with respect to  FIG. 12 , the ribbon  30  may be terminated by clamping the ribbon  30  above the bond head  40  with the clamp  45  or by locking of the ribbon spool. Following the clamping of the ribbon  30 , the bond header  40  is moved in a manner leading to breaking of the ribbon  30  in the vicinity of second bond site  55 . Additional ribbon  30  can then be played out from the ribbon spool in order to be disposed under the bond foot  50  for re-initiation of the bonding process as described above. 
     In one embodiment of the invention, “security welds”, i.e., double or other multiple welds, may be effected at each bond site. These security welds serve to increase the contact area for improved current flow, mechanical strength, and reliability. The system  10  makes the weld, moves slightly and welds the ribbon again to the same terminal. The welds may overlap, may combine to form a single uniform weld, or may be completely separate effecting discrete welds. 
     The system  10  can be a fully automatic, semi-automatic or manual machine. The difference among these applications would lie primarily in the use of programmability and pattern recognition features. In one embodiment, the resistance welding process as described is automated. For example, a device may be presented to the system  10  by manual placement on a work holder or automatically by a conveyor system. The position of the device may be determined by pattern recognition, as is known in the art. Preferably, pattern recognition systems and motion algorithms automatically compensate for variations in positions of the bond sites within the various assemblies in order to provide automation of the bonding process. 
     In one embodiment, as illustrated in  FIG. 1 , the optical shape or pattern recognition system includes a camera  200  supported over the bond header  40 . The bond foot  40  may be formed of a transparent material to allow the camera  200  to visualize the work area and facilitate the operation of the optical shape or pattern recognition system. 
     In one embodiment, the bond foot  40  is formed of a non-electrically conductive material. The dual electrodes of the welding tip  75  may each be made of an electrically conductive material, such as, for example, copper. One of the dual electrodes may serve as the positive electrode and the other of the dual electrodes may serve as the negative electrode. 
     As can be understood from  FIG. 9 , the ribbon  30  extends through a ribbon guide  105  on the back lower region of the bond foot  40 . Depending on the embodiment, the ribbon guide  105  may be part of the unitary construction of the bond foot. Alternatively, the guide  105  may have a multi-piece construction that allows the guide  105  to be swapped out for another guide of a different size or configuration, thereby allowing the guide  105  to be tailored to fit the exact type of ribbon  30  being employed for the welding process. Further, a guide  105  that is separately attached to the bond foot  40  may simplify the routing of the ribbon through the guide  105  during setup of the welding system. 
     As illustrated in  FIGS. 3-7 , in some embodiments, the back or heal  95  opposite the toe  90  may a cutting edge  205  defined by a hardened material having a sharp edge. The cutting edge  205  may be a hardened material bonded to the material forming the rest of the electrically non-conductive bond foot  40 . In one embodiment, the cutting edge  205  can be replaced separately from the rest of the bond foot. 
     In one embodiment, the above method may be used to bond a nickel clad copper ribbon 0.002 inches by 0.015 inches (2 mills by 15 mils). In alternate embodiments of the subject method, ribbons of Pt, Ni 205, Ni 270, and Al 6061 may be welded using the above method. 
     The foregoing merely illustrates the principles of the invention. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements and methods which, although not explicitly shown or described herein, embody the principles of the invention and are thus within the spirit and scope of the present invention. From the above description and drawings, it will be understood by those of ordinary skill in the art that the particular embodiments shown and described are for purposes of illustrations only and are not intended to limit the scope of the present invention. References to details of particular embodiments are not intended to limit the scope of the invention.