Abstract:
A wire butt welding apparatus includes at least two clamps, individual ones of the at least two clamps configured to hold a respective wire. The individual ones of the at least two clamps are positioned within the wire welder such that the ends of individual ones of the respective wires, when held by the respective clamps, will contact each other. One or more individual ones of the at least two clamps are associated with an adjustment axis about which the individual ones of the at least two clamps are configured to rotate. An adjustment mechanism is operatively coupled to fix one or more of the at least two clamps corresponding to the associated adjustment axis at an angular orientation with respect to a second clamp.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of the previously filed U.S. provisional application 61/791,371, filed on Mar. 15, 2013, which application is incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention relates generally to wire welding, and more specifically, to welding devices associated with wire bending machinery. 
       BACKGROUND 
       [0003]    Wire butt welding equipment is generally known in the industry as a means for joining the ends of two or more wires, sometimes creating a closed wire figure. Wire welders use clamps to grasp the respective ends of wires to be welded together. The clamps hold the respective ends of the wires in contact with each other, and the welder applies a tip force to press the ends of the wires together. In a resistive wire welder, electrodes within the clamps contact the wire and pass current through the respective wires to be welded. The resistance at the juncture of the two wires causes a buildup of heat, which welds the wires together. 
         [0004]    The wire butt welders known in the art are designed to weld straight pieces of wire. Wire welders associated with flexible wire bending machinery, however, must be capable of accommodating a variety of parts. Curved wires, wires with angled segments, or wires needing to be welded at an angle relative to each other (as opposed to forming a straight line with the two wire ends) require angular adjustment of the electrodes of the wire welder to properly align the ends of the wires. Known wire welders are designed with clamps that are not, themselves, capable of angular adjustment. Instead, the known wire welders rely upon electrodes that must be angularly adjusted. To accommodate this adjustment, the wire welders known in the art use electrodes with slotted mounting holes. An exemplary prior art electrode is illustrated in  FIG. 13 . The electrode  330  has grooves  331  and  332  positioned at either side of the electrode. The grooves  331  and  332  are substantially cylindrical such that they receive and maintain contact with the outer surface of a round wire. In a wire butt-welder, two electrodes  330  grasp each end of the respective wires that are to be welded by the welder. The electrodes  330  are positioned substantially opposite each other, across the centerline of the wire. A holding force clamps the wire between the electrodes  330 . The electrode has a through-hole  334  used to locate or attach the electrode to a jaw of a wire butt-welder. In addition, the electrode has arc shaped slots  333  that facilitate angular adjustment of the electrodes relative to the clamps. By adjusting the angle of the electrodes  330 , the ends of the wires to be welded can be aligned with one another. 
         [0005]    Over time and repeated use, slotted electrodes slip relative to the clamps. Further, all types of electrodes accumulate build up due to welding material that has not been cleaned. This build-up affects the angular alignment of wires held by the electrodes  330 . In addition, the electrodes  330  typically need to be adjusted every time the wire butt-welder is configured to run a different part. The electrodes are frequently adjusted to maintain proper alignment of the wire ends within the welder, particularly in situations where a welder runs high volumes of parts or parts requiring a variety of angular alignments. The slotted electrodes previously known in the art required individual adjustment—meaning each electrode needed to be adjusted by loosening bolts screwed through the slotted holes and manually changing the angle of the electrode. This process was difficult and time-consuming in part because the electrodes tend to slip when the bolts are re-tightened. The time required to adjust the electrodes reduces the productivity of the welding equipment. The adjustment and slippage also imparts mechanical wear on the electrodes, both at the wire/material interface surface with the electrodes and at the mounting surface of the electrode. Reducing the need for adjustment, or simplifying the process of adjusting electrodes, is therefore desirable. 
         [0006]    Slotted, angularly adjustable electrodes are more expensive than similar electrodes that have a simple through-hole for fixed mounting to the clamp. Electrodes used in wire butt welders are a consumable part of the machine, due to the stresses imparted by high temperatures, electrical current, and mechanical wear. Reducing the cost of the electrodes used on the wire welder is therefore desirable. 
       SUMMARY 
       [0007]    Generally speaking and pursuant to these various embodiments, a wire butt welding apparatus is provided that includes at least two clamps, each clamp comprising a first jaw and a second jaw. In a resistive wire welder, the respective jaws serve as an electrode configured to pass electrical current to the wires being welded. Individual ones of the respective jaws may have a groove configured to receive a wire. The at least two clamps are positioned within the wire welder such that the groove in the first jaw of individual ones of the at least two clamps is substantially transversely aligned with the groove of every other clamp, such that the respective ends of wires held by the respective clamps will contact each other. One or more individual ones of the at least two clamps are associated with an adjustment axis about which the individual ones of the at least two clamps are configured to rotate. An adjustment mechanism is operatively coupled to fix one or more of the at least two clamps corresponding to the associated adjustment axis at an angular orientation with respect to a second clamp. 
         [0008]    The angular adjustment of the clamp, as a whole, means that the jaws within the clamp can be mounted at a fixed angle relative to the other clamp(s). This mounting configuration reduces the complexity and cost of the jaws because it eliminates the need for slotted mounting holes on the jaws. Using this mounting configuration, the jaws are less prone to slip relative to the clamps. In addition, the jaws are capable of passing greater forces to the wires by virtue of using simple through-holes to mount the jaws to the clamp. This serves the added benefit of imparting greater holding forces to the wires being welded, which reduces slippage of the wires within the jaws. The reduction in slippage of the wire and of the jaws also reduces the mechanical wear on the jaws and therefore increases their lifespan. This increases the productivity of the machine because the jaws need not be replaced as frequently. 
         [0009]    In one described example, the adjustment mechanism further includes a threaded nut coupled to a lever arm. The threaded nut is configured to drive the lever arm, and the lever arm is configured to rotate one or more of the at least two clamps about the associated adjustment axis in response to movement of the lever arm. In this example, the adjustment mechanism may further include a threaded rod translationally fixed to the welding apparatus, the threaded rod configured to displace the threaded nut in response to rotation of the threaded rod. These elements can be manually or mechanically driven. 
         [0010]    This adjustment mechanism simplifies changing the angular adjustment of the clamps. The mechanism therefore increases the overall productivity of the wire butt welder because less time is needed to adjust the machine when setting up the machine to run new parts, or when correcting the adjustment to accommodate ordinary wear on the jaws. 
         [0011]    In other described examples, the wire butt welding apparatus further includes mechanisms for advancing and retracting the clamps, or for raising and lowering the clamps, or for translating the clamps toward or away from each other. These features enable the wire butt welding apparatus to grasp wires and weld them, maintaining the angular adjustment of the clamps. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The above needs are at least partially met through provision of an adjustable butt welder described in the following detailed description, particularly when studied in conjunction with the drawings, wherein: 
           [0013]      FIG. 1  comprises a perspective view of the wire butt welder, shown with welder head retracted and in a lowered position with the right clamp refracted away from the left clamp; 
           [0014]      FIG. 2  comprises a perspective view of the wire butt welder, shown with welder head retracted and in a raised position with the right clamp retracted away from the left clamp; 
           [0015]      FIG. 3  comprises a perspective view of the wire butt welder, shown with welder head advanced and in a lowered position with the right clamp refracted away from the left clamp; 
           [0016]      FIG. 4  comprises a perspective view of the wire butt welder, shown with welder head advanced and in a lowered position with the right clamp advanced towards the left clamp, and with both clamps opened; 
           [0017]      FIG. 5  comprises a perspective view of the wire butt welder, shown with welder head advanced and in a raised position where the clamps have been adjusted to have a convex angle; 
           [0018]      FIG. 6  comprises a perspective view of the wire butt welder, shown with welder head retracted and in a raised position where the clamps have been adjusted to have a convex angle; 
           [0019]      FIG. 7  comprises a perspective view of the wire butt welder, shown with welder head advanced and in a raised position where the clamps have been adjusted to have a concave angle; 
           [0020]      FIG. 8  comprises a perspective view of the wire butt welder, shown with welder head retracted and in a raised position where the clamps have been adjusted to have a concave angle; 
           [0021]      FIG. 9  comprises a front view of the wire butt welder, shown with clamps in a raised position where the clamps have been adjusted to have a concave angle; 
           [0022]      FIG. 10  comprises a perspective view of the wire butt welder, shown with clamps in a raised position where the clamps have been adjusted to have a convex angle; 
           [0023]      FIG. 11A  comprises a perspective view of the top electrode insert of the wire butt welder; 
           [0024]      FIG. 11B  comprises a perspective view of the bottom electrode insert of the wire butt welder; 
           [0025]      FIG. 11C  comprises a perspective view of an alternative bottom electrode insert of the wire butt welder, for use with curved wires or rings; 
           [0026]      FIG. 12  comprises a schematic illustration of the alternative bottom electrode inserts from  FIG. 11C  and the top electrode from  FIG. 11A  with wires in place; 
           [0027]      FIG. 13  comprises a perspective view of the electrode from a prior art wire butt welder, illustrating slotted adjustment channels machined into the jaw; 
           [0028]      FIG. 14  illustrates misalignment of two wires. 
       
    
    
       [0029]    Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein. 
       DETAILED DESCRIPTION 
       [0030]    In one embodiment, the wire butt welder is a welding unit that is placed in front of a steel wire bending machine. The wire butt welder is designed to operate in an automated fashion in concert with a wire bending machine. The wire butt welder is accordingly designed to produce high volumes of parts. This approach stands in contrast to many prior butt-welding devices, which are designed for manual operation in low volume operating environments. Aspects of the wire butt welder are designed for automation, starting with the ability to automatically pick parts from the wire bending machine, continuing with a programmable automatic weld cycle, and ending when the part is released from the welder. Automated wire bending machines are capable of forming a variety of wire sizes. The cross-sectional profile of the wire may be circular, oval, or multi-sided such as square. Other cross-sectional wire shapes are possible. In one embodiment, the wire butt welder is capable of joining two pieces of steel wire together through means of resistance welding. Resistance welding uses the parent material(s) to join the two pieces of wire together. The amount of current needing to be applied at a specific time (measured in cycles) is dependent on the thickness and conductivity of the material being welded. 
         [0031]      FIGS. 1-10  illustrate an example of the adjustable welding mechanism. Elements of each drawing figure are numbered consistently throughout the figures. The adjustable welding mechanism consists of a left side clamping mechanism  300  and a right side clamping mechanism  301 , as labeled on  FIG. 9  and  FIG. 10 . The two clamping mechanisms  300  and  301  are substantially mirror images of one another for purposes of clamping and orienting wires to be butt welded together. The ends of two wires are held by the respective clamping mechanisms  300  and  301  during wire welding operations, such that the wires may be butt-welded together. To facilitate the butt-welding operation, the adjustable welding mechanism is designed such that the wires are substantially transversely aligned when clamped within the respective clamping mechanisms  300  and  301 . The clamping mechanisms  300  and  301  include a top jaw  350  that pivots on the shaft  355  of an actuator  410 , and a bottom jaw  360  that is rotationally fixed. The top jaw  350  receives a top electrode insert  310  that is further described in reference to  FIG. 11A . The bottom jaw  360  receives a bottom electrode insert  320  that is further described in reference to  FIG. 11B . Each of the electrodes  310  and  320  has a groove that receives the wire. When adjusted to create a straight wire weld, the grooves in the respective electrodes  310  and  320  of the respective clamping mechanisms  300  and  301  are substantially parallel and coincident. 
         [0032]    The top electrode insert  310  is secured to the top jaw  350  by a bolt  315  that passes through the top jaw  350  and engages threads cut in the top electrode insert  310 . The bottom electrode insert  320  is secured to the bottom jaw  360  by a pair of bolts  325  (see  FIGS. 9 and 10 ) that pass through the bottom electrode insert  320  and engage threads cut in the bottom jaw  360 . Many alternative means of securing the top electrode inserts  310  and the bottom electrode inserts  320  could be implemented, as will be appreciated by a person having ordinary skill in the art. The electrode inserts  310  and  320  are designed as consumable parts within the adjustable welder and should preferably be easy to replace and align within the welder. 
         [0033]    The two top welding jaws  350  open and close relative to the bottom jaw  360  when the shaft  355  is rotated by the actuator  410 .  FIG. 4  illustrates the clamps in an open position, and the remaining  FIGS. 1-3  and  FIGS. 5-10  illustrate the clamps in a closed position in which the clamps grip and hold the wire. The jaws  350  and  360  open as illustrated in  FIG. 4  so that the clamping mechanisms  300  and  301  may respectively receive wires to be welded. When closed, the jaws  350  and  360  securely hold and align wires to be welded. The actuator  410  applies a holding torque to the shaft  355 , such that the clamps apply a holding force to the wire via the top electrode inserts  310  and the bottom electrode inserts  320 . This holding force is sufficient to prevent the wire from sliding between the electrode inserts  310  and  320  when a tip force is applied to weld the ends of the wires together. 
         [0034]    The welder head traverses forward to retrieve a wire frame from the machine.  FIGS. 3-5 , and  FIG. 7  illustrate the welder head at an advanced position and  FIG. 1 ,  FIG. 2 ,  FIG. 6  and  FIG. 8  illustrate the welder head at a retracted position. The clamping mechanisms  300  and  301  are advanced and retracted by pneumatic actuators  240  that drive a piston  250  against a collar  260 . All components of the clamping mechanisms  300  and  301 , including at least the jaws  350  and  360  and the actuators  410 , are fixed to a support structure  270  that advances and retracts relative to a fixed element  220 . The collar  260  interacts with a spline shaft  230  to maintain the angular alignment of the clamping mechanism at all positions between a retracted position and an advanced position. As will be observed in  FIGS. 5 and 7 , the spline shaft  230  advances through the collar  260  as the clamping mechanism moves to the advanced position. By comparison,  FIGS. 6 and 8  show the spline shaft  230  retracted. To advance the clamping mechanisms  300  and  301 , the piston  250  pulls the collar  260  towards the pneumatic actuator  240 . When pulled by the piston  250 , the collar  260  engages the fixed element  220  to drive the clamping mechanism  300  or  301  forward. To retract the clamping mechanisms  300  and  301 , the piston  250  pushes the collar  260  away from the pneumatic actuator  240 . When pushed by the piston  250 , the collar  260  pulls against the fixed element  220  to drive the clamping mechanism  300  or  301  backward. 
         [0035]    The welding electrodes  310  and  320  (4 in a set) that hold the wire during the welding procedure bolt onto the welding jaws  350  and  360 . Copper contact bars  420  are stationary, and when in contact with the welding clamps  360 , they provide the electrical current needed to weld. Due to heat and electrical current generated during butt welding operations, the electrode inserts  310  and  320  will accumulate build-up of welding material. Cleaning the electrode inserts  310  and  320 , which is required to remove this build-up, will eventually degrade the shape of the inserts  310  and  320 . As they degrade in this fashion, the electrode inserts  310  and  320  become less efficient at passing current to wires held within the electrodes. In addition, degraded electrode inserts  310  and  320  require a greater holding force to prevent the wire from sliding within the electrode inserts  310  and  320  when a tipping force is applied to weld the wires. 
         [0036]    To accommodate changes in the electrodes due to material build-up and also to address the different angular alignment required by different parts, the wire butt-welder allows for adjustment of the wire angle.  FIGS. 5-6  and  FIG. 10  illustrate the wire butt-welder adjusted to create a convex angle (creating a peak shaped like the letter “A”) between the two wires to be welded.  FIGS. 7-9  illustrate the wire butt-welder adjusted to create a concave angle (creating a valley shaped like the letter “V”) between the two wires to be welded. By changing the angle of the wires, the wire butt-welder can accommodate curved wires such as rings, wires with angled segments, or wires needing to be welded at an angle relative to each other (as opposed to forming a straight line with the two wire ends), which require angular adjustment of the electrodes of the wire welder to properly align the ends of the wires. The adjustability of the angle also allows the machine operator to fine tune the orientation of parts either during setup or in between welding operations. This fine tuning capability allows the operator to manufacture parts consistently at tighter tolerances—specifically, the adjustable wire welder is capable of manufacturing smaller circular rings than prior art devices because it is capable of holding the tighter tolerances associated with these smaller rings. 
         [0037]    In one example, the butt welder has a pair of knobs  110  associated with the left and right clamping mechanisms  300  and  301 . The knobs  110  are connected to respective threaded rods  120 . Turning the knob  110  turns the threaded rod  120  and causes a threaded nut  130  to travel along the length of the threaded rod  110 . The threaded rod  110  is affixed at one end in a thrust bearing mechanism  140  to a rotationally fixed element  220  of the clamping mechanism  300  or  301 . The travel of the threaded nut  160  causes the clamping mechanism  300  or  301  to rotate relative to the welder head on an axis defined by the splined shaft  230 , which is keyed  215  to a bracket  210  that supports the actuator  410  and the clamps  350  and  360 . The threaded nut  260  is mounted to a structure extending from the collar  260 , such that the collar  260  pivots the clamping mechanism  300  or  301  along an adjustment axis defined by the splined shaft  230 . The collar  260  therefore provides a lever arm that defines the angular adjustment of the clamping mechanisms  300  and  301 . An indicator  160  protrudes at the end of the lever arm to indicate the angle of the clamping mechanism  300  or  301 . A locking nut  150  rides an arc slot  220  cut in the collar  260 . By tightening the locking nut  150 , the angle of the clamping mechanism  300  or  301  is fixed.  FIGS. 9 and 10  illustrate a front view of the welding head and illustrate the clamping mechanisms  300  and  301  at two different angles of rotation. Other mechanisms including, but not limited to, different configurations of the threaded rod and the lever arm could be used to manipulate the clamp&#39;s angle. In addition, the angular adjustment may be driven by a variety of powered motors or actuators, including pneumatic, hydraulic, or electric actuators as would be understood by a person having ordinary skill in the art. 
         [0038]    The clamping mechanisms  300  and  301  may be raised and lowered to retrieve wires from a wire forming machine.  FIG. 1 ,  FIG. 3 , and  FIG. 4  illustrate the welder head in a lowered position and  FIG. 2 , and  FIGS. 5-10  illustrate the welder head in a raised position. The welder heads are raised and lowered by pneumatic cylinders (not shown) that push the heads upwards until an adjustable bumper  430  hits a stop  440 . Other examples might use hydraulic or electrical actuators to raise and lower the clamping mechanisms  300  and  301 . 
         [0039]    A tip force is applied to the wires to be butt welded by a tip force/retract cylinder (not shown). In the illustrated example, tip force/retract cylinder is a pneumatic actuator. The tip force and retract pressure are controlled by a pressure gauge mounted on side of the welder (not shown). The tip force pushes the ends of the wires together during a welding operation. Other examples might use hydraulic or electrical actuators to achieve the tip force. The tip force draws the two clamping mechanisms  300  and  301  together.  FIG. 4  illustrates the clamping mechanisms  300  and  301  at a position drawn together, as compared to  FIG. 3  in which the clamping mechanisms are spread apart from one another. In the illustrated example, the right side clamping mechanism  301  is mounted on a track  280  such that the clamping mechanism  301  as a whole is translated by the tip force/retract cylinder. In alternative examples, the two clamping mechanisms  300  and  301  could be configured to move differently by moving either or both of the clamping mechanisms  300  and  301 . 
         [0040]      FIG. 11A  illustrates an example top electrode insert  310  in detail. Two grooves  311  and  312  appear on the same face of the top electrode insert  310 . Electrodes may also be custom designed with curved or angled grooves  311  and  312  to accommodate curved wires such as rings or for wires formed with angled segments. The grooves  311  and  312  may be selected to secure the wire by unscrewing the top electrode insert  310 , rotating the insert 180 degrees, and then re-screwing the insert to the top clamp  350 . In one example, the grooves  311  and  312  are the same size, which allows a machine operator to rotate the insert  310  to use a fresh groove after the first groove has degraded. In another example, the groove  311  has a different radius from the groove  312 . The groove  311  may match the diameter of a first size of wire, while the groove  312  may match the diameter of a second size of wire, which allows a machine operator to select a groove based on the wire to be welded by the adjustable welding apparatus. A threaded through-hole  313  extends through the top electrode insert  310 , such that the bolt  315  can be threaded to the insert  310 . 
         [0041]      FIG. 11B  illustrates an example bottom electrode insert  320  in detail. Two grooves  322  and  323  appear on the same face of the bottom electrode insert  320 . Electrodes may also be custom designed with curved or angled grooves  322  and  323  to accommodate curved wires such as rings or for wires formed with angled segments. In one example, the grooves  322  and  323  are the same size, which allows a machine operator to rotate the insert  320  to use a fresh groove after the first groove has degraded. In another example, the groove  322  has a different radius from the groove  323 . The groove  322  may match the diameter of a first size of wire, while the groove  323  may match the diameter of a second size of wire, which allows a machine operator to select a groove based on the wire to be welded by the adjustable welding apparatus. Counter-sunk through holes  321  are designed to fit cap screws  325  that secure the bottom electrode insert  320  to the bottom clamp  360 . The welding inserts  310  and  320 —and specifically the grooves  311 ,  322 ,  312 , and  323 —must be properly dressed between jobs or when considerable build up is noticed. 
         [0042]      FIG. 11C  illustrates the details of an example bottom electrode  320  for use with curved wires or rings. Two grooves  322  and  323  are provided to support a wire. In the example illustrated in  FIG. 11C , the grooves  322  and  323  are angled and slightly curved to support a curved wire ring. As with the example illustrated in  FIG. 11B , the bottom electrode illustrated in  FIG. 11C  is reversible to provide double the longevity of the tooling, in the instance where the grooves  322  and  323  are the same size, or for use with differently sized wire, in the instance where grooves  322  and  323  match the respective wires. To provide clearance for the curved wire, the grooves  322  and  323  are shortened, and material is removed from a clearance region  324 . Counter-sunk through holes  321  are designed to fit cap screws  325  that secure the bottom electrode insert  320  to the bottom clamp  360 . 
         [0043]      FIG. 12  illustrates the bottom electrodes from  FIG. 11C  and the top electrodes from  FIG. 11A , in use with a first wire end  20  and a second wire end  30 . The electrode  310  and  320  clamp the respective ends of the wire. The clearance region  324  of the bottom electrode  320  leaves space for the wire to pass around the screws  325  that secure the bottom electrode to the lower jaw  360 . 
         [0044]    When setting up the adjustable wire welder the welder must be aligned with reference to the bending unit on the wire forming machine. When picking up a wire, there should be equal spacing between the ends of the wire and the clamps on both sides of the wire, i.e., from the butt weld to each electrode. Depending on the wire size or required weld type the welder has to grip the wire closer or further away from the ends of wire on formed part. The entire butt welder should be moved left or right to achieve equal spacing. The welder head may be manually advanced to make it easier to see the spacing between the wire ends and the electrodes. 
         [0045]    The next step would be aligning welder heights to the wire forming machine. In addition, when changing the tools from one wire gauge to another there will be a height variation on the left pick-up cylinder. 
         [0046]    Next, adjusting the clamps facilitates achieving a straight weld or a weld with the desired angle. This is accomplished by loosening the locking nut  150  and turning the knob  110  on the clamp&#39;s angular adjustment mechanism. As shown in  FIG. 13 , the weld is not straight and needs to be adjusted to form a straight part. Over time, the welding electrodes will accumulate build up due to welding material that has not been cleaned; this will cause angular misalignment. Typical practice is to “prep” the electrodes between wire changes and jobs with an electrode dressing tool with the proper face contour covered with a very fine polishing cloth of 280-grit abrasive coarseness. Over time, however, the electrodes will inevitably degrade somewhat and may need further angular adjustment. 
         [0047]    The left and right clamping mechanisms  300  and  301  are independently adjustable, to allow simple setup and angular adjustment of the welding assembly. This allows the machine operator to first square the left side  300  in relation to a wire forming machine (not shown). After the left side is adjusted to the position of the wire on the machine, adjustments to align the wires should only be made to the right side  301 . 
         [0048]    During operation, the following issues might arise. If the welds are inconsistent, typically the welder is not applying enough clamp pressure or tip force is too high or too low. Another cause of inconsistent welds is if the electrodes are slipping on the wire when applying tip force. Excessive spark expulsion while welding is frequently caused by a tip force that is too low or too much heat and too little weld time. A welded part that does not have an even weld is often caused by fouling of the electrodes. To cure this problem, the operator must clean the electrodes and/or adjust the angle of the electrodes. 
         [0049]    Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept.