Dual wire welding or additive manufacturing contact tip and diffuser
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- LINCOLN GLOBAL INC
- Filing Date
- 2024-11-08
- Publication Date
- 2026-07-03
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to (a) U.S. Patent Application No. 16 / 295,571, filed March 7, 2019, which is incorporated by reference herein as if reproduced in its entirety; (b) U.S. Patent Application No. 16 / 267,476, filed February 5, 2019, which is incorporated by reference herein as if reproduced in its entirety; and (c) U.S. Provisional Patent Application No. 62 / 750,893, filed October 26, 2018, which is incorporated by reference herein as if reproduced in its entirety.
[0002] The devices, systems, and methods according to the present invention relate to material deposition using a dual wire configuration. [Background technology]
[0003] When welding, it is often desirable to increase the width of the weld bead or to increase the length of the weld puddle during welding. There can be many different reasons why this is desirable, which are well known in the welding industry. For example, it may be desirable to lengthen the weld puddle to keep the weld metal and filler metal molten for a longer period of time in order to reduce porosity. That is, if the weld puddle is molten for a longer period of time, harmful gases have more time to escape the weld bead before the bead solidifies. Additionally, it may be desirable to increase the width of the weld bead to cover a wider weld gap or to increase the weld deposition rate. In both cases, it is common to use an electrode with an increased diameter. Increasing the diameter increases both the length and width of the weld puddle, even though it is desirable to increase only the width or only the length of the weld puddle, rather than both width and length. However, this does not come without drawbacks. In particular, the larger the electrode utilized, the more energy is required in the welding arc to promote a proper weld. This energy increase increases the heat input to the weld, and because the diameter of the electrode used is larger, more energy is used in the welding operation. Additionally, it may produce a weld bead profile or cross section that is not ideal for certain mechanical applications. Rather than increasing the electrode diameter, it may be desirable to use at least two smaller electrodes simultaneously. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] US Patent Application Publication No. 2013 / 0264323 Summary of the Invention [Means for solving the problem]
[0005] Summary of the Invention The following summary presents a simplified summary to provide a basic understanding of some aspects of the devices, systems, and / or methods discussed herein. This summary is not an extensive overview of the devices, systems, and / or methods discussed herein. It is not intended to identify key elements of such devices, systems, and / or methods or to delineate the scope of such devices, systems, and / or methods. The sole purpose of the following summary is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
[0006] According to one aspect of the invention, a welded or additively manufactured contact tip is provided. The contact tip includes a conductive body extending from a proximal end to a distal end of the body. The body defines a first bore terminating at a first exit orifice at a distal surface of the body and a second bore terminating at a second exit orifice at a distal surface of the body. The first and second exit orifices are spaced apart from one another by a distance configured to promote formation of a bridge droplet between a first wire electrode fed through the first bore and a second wire electrode fed through the second bore during a deposition operation.
[0007] According to another aspect of the invention, a welded or additively manufactured contact tip is provided. The contact tip includes a conductive body extending from a proximal end to a distal end of the body. The body defines a first bore therethrough extending from a first entrance orifice at the proximal end of the body to a first exit orifice at the distal end of the body and a second bore therethrough extending from a second entrance orifice at the proximal end of the body to a second exit orifice at the distal end of the body. The first and second exit orifices are separated from each other by a distance configured to promote formation of a bridge droplet between a first wire electrode fed through the first bore and a second wire electrode fed through the second bore during a deposition operation. The bridge droplet bonds the first wire electrode to the second wire electrode prior to contacting a molten puddle created by the deposition operation.
[0008] According to another aspect of the invention, a welded or additively manufactured contact tip is provided. The contact tip includes a conductive body extending from a proximal end to a distal end of the body. The body forms a first channel terminating at a distal surface of the body and a second channel terminating at a distal surface of the body. At the distal surface of the body, the first and second channels are separated from each other by a distance configured to promote formation of a bridge droplet between a first wire electrode routed through the first channel and a second wire electrode routed through the second channel during a deposition operation. The bridge droplet bonds the first wire electrode to the second wire electrode prior to contacting a molten puddle created by the deposition operation.
[0009] These and / or other aspects of the present invention will become more apparent from the detailed description of exemplary embodiments of the present invention, taken in conjunction with the accompanying drawings, in which: [Brief description of the drawings]
[0010] [Figure 1] 1 illustrates a diagrammatic representation of an exemplary embodiment of a welding system of the present invention; [Diagram 2] 1 illustrates a pictorial representation of an exemplary contact tip assembly in one embodiment of the present invention. [Figure 3A-3C] 1 illustrates a pictorial representation of a welding operation in an exemplary embodiment of the present invention. [Figure 4A-4B] 1 shows a pictorial representation of the interaction of electric current and magnetic field in an exemplary embodiment of the present invention. [Figure 5A-5B] FIG. 5A shows a pictorial representation of an exemplary weld bead using a single wire, and FIG. 5B shows a pictorial representation of an exemplary weld bead using one embodiment of the present invention. [Figure 6] 1 illustrates a pictorial representation of an exemplary welding process flow chart in one embodiment of the present invention. [Figure 7] 1 illustrates a diagrammatic representation of an alternative embodiment of a contact tip assembly for use with embodiments of the present invention. [Figure 8] 4 illustrates a pictorial representation of an exemplary welding current waveform in an embodiment of the present invention. [Figure 9]4 illustrates a pictorial representation of a further exemplary welding current waveform in accordance with an embodiment of the present invention. [Figure 10] 4 illustrates a pictorial representation of an additional exemplary welding current waveform in accordance with an embodiment of the present invention. [Figure 11] 1 shows a portion of a welding torch. [Figure 12] FIG. 2 is a perspective view of a contact tip and a diffuser. [Figure 13] FIG. 2 is a perspective view of a contact tip. [Figure 14] FIG. 2 is a perspective view of a contact tip. [Figure 15] FIG. [Figure 16] FIG. [Figure 17] FIG. 2 is a perspective view of a contact tip and a bias spring. [Figure 18] A perspective view of the contact tip, bias spring, and diffuser is shown. [Figure 19] 1 shows a portion of a welding torch. [Figure 20] FIG. 2 is a perspective view of a contact tip and a diffuser. [Figure 21] FIG. 2 is a perspective view of a contact tip. [Figure 22] FIG. 2 is a perspective view of a contact tip and a diffuser. [Diagram 23] FIG. 2 is a perspective view of a contact tip and a diffuser. [Figure 24] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. The exemplary embodiments described are intended to aid in the understanding of the present invention and are not intended to limit the scope of the invention in any way. Like reference numbers refer to like elements throughout.
[0012] As used herein, "at least one," "one or more," and "and / or" are open-ended expressions that function both as conjunctions and disjunctions. For example, the phrases "at least one of A, B, and C," "at least one of A, B, or C," "one or more of A, B, and C," "one or more of A, B, or C," and "A, B, and / or C" mean A only, B only, C only, A and B together, A and C together, B and C together, or A, B, and C together, respectively. Any disjunction or disjunction phrase presenting two or more alternative terms, whether in the description of the embodiments, the claims, or the drawings, should be understood as intending the possibility of including one of the terms, either one of the terms, or both of the terms. For example, the phrase "A or B" should be understood as encompassing the possibilities of "A," "B," or "A and B."
[0013] Although the embodiments of the invention discussed herein are discussed in the context of GMAW-type welding, other embodiments of the invention are not so limited. For example, the embodiments can be utilized in SAW and FCAW-type welding operations, as well as other similar types of welding operations. Additionally, while the electrodes described herein are solid electrodes, again, embodiments of the invention are not limited to the use of solid electrodes, and cored arc welding electrodes (either flux-cored or metal-cored) can also be used without departing from the spirit or scope of the invention. Additionally, embodiments of the invention can also be used in manual, semi-automatic, and robotic welding operations. Such systems are well known and will not be described in detail herein.
[0014] Referring now to the figures, FIG. 1 illustrates an exemplary embodiment of a welding system 100 in accordance with an exemplary embodiment of the present invention. The welding system 100 includes a welding power source 109 coupled to both a welding torch 111 (having a contact tip assembly - not shown) and a wire feeder 105. The power source 109 can be any known type of welding power source capable of delivering electrical current and welding waveforms as described herein, e.g., pulsed spray, STT, and / or short arc type welding waveforms. The construction, design, and operation of such power sources are well known and need not be described in detail herein. It is also noted that welding power can be supplied by two or more power sources simultaneously - again, the operation of such systems is known. The power source 109 can also include a controller 120, which is coupled to a user interface to allow a user to input control or welding parameters of the welding operation. The controller 120 can have a processor, CPU, memory, etc. used to control the operation of the welding process as described herein. The torch 111 may be configured similarly to known manual, semi-automatic, or robotic welding torches, may couple to any known or used welding gun, and may be straight or gooseneck type as described above. The wire feeder 105 draws the electrodes E1 and E2, respectively, from electrode sources 101 and 103, which may be any known type, such as reels, spools, containers, etc. The wire feeder 105 is of known configuration and utilizes a feed roller 107 to draw the electrodes E1 and E2 and push the electrodes towards the torch 111. In an exemplary embodiment of the invention, the feed roller 107 and wire feeder 105 are configured for single electrode operation. An embodiment of the invention using a dual wire configuration may be utilized in conjunction with a wire feeder 105 and roller 107 designed only for single wire feed operation. For example, the roller 107 may be configured for a single 0.045 inch diameter electrode, but suitable for driving two 0.030 inch diameter electrodes without modification of the wire feeder 105 or roller 107.Alternatively, the wire feeder 105 can be designed to provide separate sets of rollers that each feed the electrodes E1 / E2, or to have rollers configured to feed two or more electrodes simultaneously (e.g., via a trapezoidal wire receiving groove around the periphery of the roller that can accommodate two electrodes). In other embodiments, two separate wire feeders can be used. As shown, the wire feeder 105 is in communication with a power source 109 in accordance with known configurations of welding operations.
[0015] Driven by roller 107, electrodes E1 and E2 are threaded through liner 113 to feed electrodes E1 and E2 to torch 111. Liner 113 is appropriately sized to allow electrodes E1 and E2 to pass to torch 111. For example, for two 0.030 inch diameter electrodes, a standard 0.0625 inch diameter liner 113 (typically used for a single 0.0625 inch diameter electrode) can be used without modification.
[0016] While the above referenced examples discuss the use of two electrodes having the same diameter, the invention is not limited thereto and electrodes of any diameter may be used. That is, embodiments of the invention may use a first larger diameter electrode and a second smaller diameter electrode. In such embodiments, two workpieces of different thicknesses may be more conveniently welded. For example, a larger electrode may be directed to a larger workpiece while a smaller electrode may be directed to a smaller workpiece. Additionally, embodiments of the invention may be used in many different types of welding operations including, but not limited to, MIG (metal inert gas), submerged arc, and flux cored welding. Additionally, embodiments of the invention may be used in automated, robotic, and semi-automatic welding operations. Additionally, embodiments of the invention may be utilized in conjunction with different electrode types. For example, it is contemplated that a cored electrode may be combined with a non-cored electrode. Additionally, electrodes of different compositions may be used to achieve desired weld attributes and final weld bead composition. Thus, embodiments of the invention may be utilized in a wide range of welding operations.
[0017] FIG. 2 illustrates an exemplary contact tip assembly 200 of the present invention. The contact tip assembly 200 can be made from known contact tip materials and can be used with any known type of welding gun. As shown in this exemplary embodiment, the contact tip assembly has two separate channels 201 and 203 that run the length of the contact tip assembly 200. During welding, a first electrode E1 is threaded through the first channel 201 and a second electrode E2 is threaded through the second channel 203. The channels 201 / 203 are typically sized appropriately for the diameter of the wire that is threaded therethrough. For example, if the electrodes have the same diameter, the channels have the same diameter. However, if different diameters are to be used, the channels should be sized appropriately to properly pass current through the electrodes. Additionally, in the embodiment shown, the channels 201 / 203 are configured such that the electrodes E1 / E2 exit the distal face of the contact tip 200 in a parallel relationship. However, in other exemplary embodiments, the channel can be configured such that electrodes E1 / E2 exit the distal face of the contact tip such that an angle in the range of + / - 15° exists between the centerlines of each electrode. The angle can be determined based on the desired performance characteristics of the welding operation. It is further noted that in some exemplary embodiments, the contact tip assembly can be one contact tip integrated with the channel as shown, while in other embodiments, the contact tip assembly can be comprised of two contact tip subassemblies positioned near each other with current directed to each contact tip subassembly.
[0018] As shown in FIG. 2, each electrode E1 / E2 is spaced apart by a distance S, which is the distance between the closest edges of the electrodes. In an exemplary embodiment of the invention, this distance is in the range of 0.25 to 4 times the diameter of the larger of the two electrodes E1 / E2, while in other exemplary embodiments, the distance S is in the range of 2 to 3 times the maximum diameter. For example, if each electrode has a diameter of 1 mm, the distance S can be in the range of 2 mm to 3 mm. In other exemplary embodiments, the distance S is in the range of 0.25 to 2.25 times the diameter of one of the wire electrodes, such as the larger of the two electrodes. In a manual or semi-automatic welding operation, the distance S can be in the range of 0.25 to 2.25 times the maximum electrode diameter, while in a robotic welding operation, the distance S can be in the same range or another range, such as 2.5 to 3.5 times the maximum electrode diameter. In an exemplary embodiment, the distance S is in the range of 0.2 mm to 3.5 mm.
[0019] The wire electrodes E1 / E2 protrude from exit orifices at the end face of the contact tip 200. The diameter of the exit orifices is slightly larger than the diameter of the wire electrodes E1 / E2. For example, for a 0.035 inch wire, the diameter of the exit orifice can be 0.043 inches, for a 0.040 inch wire, the diameter of the exit orifice can be 0.046 inches, and for a 0.045 inch wire, the diameter of the exit orifice can be 0.052 inches. The channels 201, 203 and the exit orifice are appropriately spaced to promote the formation of a single bridge droplet between the wire electrodes E1 / E2 during the welding operation. For exit orifices sized for electrodes having a diameter of 0.045 inches or less, the distance between the exit orifices (the inner circumference distance as well as the distance S) can be less than 3 mm to promote the formation of a bridge droplet. However, spacing of 3 mm or more between the exit orifices may be possible depending on the wire size, magnetic strength, orientation (e.g., angle) of the channels 201, 203, etc. In certain embodiments, the distance between the exit orifices is within the range of 20% to 200% of the diameter of one or both of the exit orifices, which may also correspond to a distance S between the wire electrodes within the range of 0.25 to 2.25 times the diameter of the electrodes.
[0020] As will be further described below, the distance S should be selected to ensure that a bridge droplet is formed between the electrodes while preventing the electrodes from contacting each other except through the bridge droplet before the droplet is transferred.
[0021] 3A illustrates an exemplary embodiment of the present invention, showing the interaction of magnetic forces from each electrode E1 and E2. As shown, due to the flow of current, a magnetic field is generated around the electrodes, which tends to create a pinching force that draws the wires towards each other. This magnetic force tends to create a droplet bridge between the two electrodes, which is described in more detail below.
[0022] FIG. 3B shows a droplet bridge created between two electrodes; that is, as current through each electrode melts the ends of the electrodes, magnetic forces tend to draw the molten droplets toward each other until they are joined together. The distance S is far enough so that the solid portions of the electrodes are not drawn into contact with each other, but close enough that a droplet bridge is created before the molten droplets transfer to the weld puddle created by the melting arc. The droplets are shown in FIG. 3C, where the droplet bridge produces one large droplet that transfers to the puddle during welding. As shown, the pinching magnetic force acting on the droplet bridge acts to pinch off the droplet, similar to the use of a pinching force in a single electrode welding operation.
[0023] 4A further illustrates an exemplary representation of current flow in one embodiment of the present invention. As shown, the welding current is split through each electrode and passed to and through the bridge droplet as it is formed. The current then flows from the bridge droplet to the puddle and to the workpiece. In an exemplary embodiment in which the electrodes are the same diameter and type, the current is essentially split equally to the electrodes. In an embodiment in which the electrodes have different resistance values, for example due to different diameters and / or compositions / configurations, the welding current is applied to a contact tip, as in known methods, which provides the welding current to each electrode through the contact between the electrode and the channel in the contact tip, so that each current is proportional to the relationship V=I * 4B shows the magnetic forces within the bridge puddle aimed at creating a bridge droplet. As shown, the magnetic forces tend to draw the molten portions of the droplet towards each other until they contact each other.
[0024] FIG. 5A shows an example cross-section of a weld made using a single electrode welding operation. As shown, while the weld bead WB is of adequate width, the finger F of the weld bead WB that penetrates into the workpiece W shown has a relatively narrow width. This can occur in a single wire welding operation when a higher deposition rate is used. That is, in such a welding operation, the finger F becomes narrow enough that it is not reliable to assume that the finger has penetrated in the desired direction, and therefore may not be a reliable indicator of adequate penetration. Furthermore, as this narrow finger becomes deeper, defects such as entrapped porosity near the finger may occur. Furthermore, in such a welding operation, the useful surface of the weld bead does not penetrate as deeply as desired. Thus, in certain applications, the mechanical bond is not as strong as desired. Furthermore, in some welding applications, such as when welding horizontal fillet welds, the use of a single electrode makes it difficult to achieve equal sized weld legs at high deposition rates without adding too much heat to the welding operation. These problems are mitigated using embodiments of the present invention, which can reduce finger penetration and spread the fingers to provide wider side penetration of the weld. An example of this is shown in FIG. 5B, which shows a weld bead of an embodiment of the present invention. As shown in this embodiment, similar or improved weld bead leg symmetry and / or length can be achieved, as well as a wider weld bead at a weld depth within the weld joint. This improved weld bead geometry is achieved while using an overall lower heat input to the weld. Thus, embodiments of the present invention can provide improved mechanical weld performance with lower amounts of heat input and improved deposition rates.
[0025] FIG. 6 illustrates a flow chart 600 of an exemplary welding operation of the present invention. This flow chart is intended to be illustrative and not limiting. As shown, a welding current / power is provided by a welding power source such that current is directed to the contact tip and electrode according to known system configurations (610). Exemplary waveforms are described further below. During welding, a bridge droplet can be formed between the electrodes (620), with each droplet from each electrode contacting each other to create a bridge droplet. The bridge droplet is formed prior to contacting the weld puddle. During the formation of the bridge droplet, at least one of the duration or droplet size is detected until the time the droplet reaches a size to be transferred, at which point the droplet is transferred to the puddle (640). The process is repeated during the welding operation. To control the welding process, the power source controller / control system can use either the bridge droplet current duration and / or bridge droplet size detection to determine whether the bridge droplet is of a size to be transferred. For example, in one embodiment, a predetermined bridge current duration is used for a given welding operation such that the bridge current is maintained for that duration, after which droplet transfer is initiated. In a further exemplary embodiment, a controller of the power source / power supply may monitor the welding current and / or voltage and utilize a predetermined threshold (e.g., a voltage threshold) for a given welding operation. For example, in such an embodiment, the power source initiates the droplet separation portion of the welding waveform when a detected arc voltage (detected via an arc voltage detection circuit of known type) detects that the arc voltage has reached a bridge droplet threshold level. This is discussed further below in several exemplary embodiments of welding waveforms that may be used in conjunction with embodiments of the present invention.
[0026] FIG. 7 illustrates an alternative exemplary embodiment of a contact tip 700 that can be used with embodiments of the present invention. As mentioned above, in some embodiments, the electrodes can be directed to the torch through a single wire guide / liner. Of course, in other embodiments, separate wire guides / liners can be used. However, in embodiments where a single wire guide / liner is used, the contact tip can be designed such that the electrodes are separated from each other within the contact tip. As shown in FIG. 7, this exemplary contact tip 700 has one inlet channel 710 with one orifice at the upstream end of the contact tip 700. Each electrode enters the contact tip through this orifice and follows the channel 710 until it reaches a separation portion 720 of the contact tip, which directs one electrode into a first exit channel 711 and the second electrode into a second exit channel 712, thereby directing the electrodes into separate exit orifices 701 and 702, respectively. Of course, channels 710, 711, and 712 should be appropriately sized for the size of the electrodes being used, and separation portion 720 should be shaped so as not to mar or scratch the electrodes. As shown in Figure 7, outlet channels 711 and 712 are angled relative to one another, although as shown in Figure 2, these channels can also be oriented parallel to one another.
[0027] 8-10, various exemplary waveforms that may be used with exemplary embodiments of the present invention are shown. In general, in exemplary embodiments of the present invention, the current is increased to create a bridge droplet and build the bridge droplet up for transfer. In exemplary embodiments, at transfer, the bridge droplet has an average diameter similar to the distance S between the electrodes and can be larger than the diameter of either of the electrodes. Once the droplet is formed, it is transferred through a high peak current and then the current is reduced to a lower level (e.g., background) to remove the arc pressure acting against the wire. The bridge current then builds the bridge droplet without exerting a pinching force large enough to pinch off the forming droplet. In exemplary embodiments, this bridge current is within a range of 30% to 70% between the background current and the peak current. In other exemplary embodiments, the bridge current is within a range of 40% to 60% between the background current and the peak current. For example, if the background current is 100 amps and the peak current is 400 amps, the bridge current is in the range of 220 amps to 280 amps (i.e., 40% to 60% of the 300 amp difference). In some embodiments, the bridge current can be maintained for a duration in the range of 1.5 ms to 8 ms, while in other exemplary embodiments, the bridge current is maintained for a duration in the range of 2 ms to 6 ms. In exemplary embodiments, the bridge current duration begins at the end of the background current state and includes the bridge power ramp, where the ramp can be in the range of 0.33 ms to 0.67 ms depending on the bridge current level and ramp rate. In exemplary embodiments of the invention, the pulse frequency of the waveform can be slowed down compared to a single wire process, thereby allowing droplet growth that can be improved in control, as well as allowing a higher deposition rate compared to single wire operation.
[0028] FIG. 8 illustrates an exemplary current waveform 800 for a pulsed spray welding type operation. As shown, the waveform 800 has a background current level 810 and then transitions to a bridge current level 820 during which the bridge droplet grows to a transition size. The bridge current level is below the spray transition current level 840 at which the droplet begins to transition to the puddle. At the end of the bridge current 820, the current rises above the spray transition current level 840 to a peak current level 830. The peak current level is then maintained for the peak duration to complete the droplet transition. After the transition, the current is again reduced to the background level and the process is repeated. Thus, in these embodiments, the transfer of a single droplet does not occur during the bridge current portion of the waveform. In such exemplary embodiments, the lower current level of the bridge current 820 allows the droplet to form without excessive pinch force to direct the droplet to the puddle. The use of bridge droplets allows a welding operation to be achieved in which the peak current 830 can be maintained at a higher level and for a longer duration than using a single wire. For example, some embodiments may maintain a peak duration in the range of 4 ms to 7 ms with a peak current level in the range of 550 amps to 700 amps and a background current in the range of 150 amps to 400 amps. In such embodiments, significantly improved deposition rates may be achieved. For example, some embodiments achieve deposition rates in the range of 19 lb / hr to 26 lb / hr, whereas a similar single wire process may only achieve deposition rates in the range of 10 lb / hr to 16 lb / hr. For example, in a non-limiting embodiment, a pair of two wires having a diameter of 0.040 inches and using a peak current of 700 amps, a background current of 180 amps, and a droplet bridge current of 340 amps may be deposited at a rate of 19 lb / hr at a frequency of 120 Hz. Such deposition is at a much lower frequency than conventional welding processes and is therefore more stable.
[0029] FIG. 9 shows another exemplary waveform 900 that can be used in a short arc style operation. Again, the waveform 900 has a background portion 910 before a short response portion 920 that is configured to clear the short between the droplet and the puddle. During the short response 920, the current is raised to clear the short, and once the short is cleared, the current is lowered to a bridge current level 930 during which a bridge droplet is formed. Again, the bridge current level 930 is less than the peak current level of the short response 920. The bridge current level 930 is maintained for a bridge current duration that causes the bridge droplet to form and move toward the puddle. During droplet transfer, the droplet current is lowered to a background level, allowing the droplet to move forward until a short occurs. Once the short occurs, the short response / bridge current waveform is repeated. It should be noted that in an embodiment of the present invention, it is the presence of the bridge droplet that makes the welding process more stable; i.e., there is no bridge droplet in a conventional welding process using multiple wires. In those processes, if one wire shorts out or touches the puddle, the arc voltage drops and the arc on the other electrode is extinguished, which does not occur in the embodiment of the present invention where the bridging droplet is common to each wire.
[0030] FIG. 10 shows a further exemplary waveform 1000, which is a STT (surface tension transfer) type waveform. Such waveforms are known and will not be described in detail herein. To further describe STT type waveforms, their structure, use, and implementation, U.S. Patent Application Publication No. 2012 / 0133994 filed on April 5, 2012, is incorporated herein in its entirety. Again, this waveform has a background level 1010 and a first peak level 1015 and a second peak level 1020, the second peak level being reached after the short between the droplet and the puddle is cleared. After the second peak current level 1020, the current is reduced to a bridge current level 1030, forming a bridge droplet, after which the current is reduced to the background level 1010, allowing the droplet to advance to the puddle until it contacts the puddle. In other embodiments, AC waveforms can be used, such as AC STT waveforms, pulsed waveforms, etc.
[0031] As discussed above, wire electrodes used in multi-wire deposition operations (e.g., welding, additive manufacturing, hardfacing, etc.) can be spaced apart a distance S that promotes the formation of bridge droplets between the wire electrodes. The size of the bridge droplet is determined by the spacing between the wire electrodes and the spacing between the exit orifices in the contact tips. The size of the bridge droplet determines the width of the electric arc that exists during the deposition operation, and as the exit orifice spacing and wire electrode spacing are reduced, the arc width decreases. Larger bridge droplets may be preferred for larger welds and smaller bridge droplets may be preferred for smaller welds. The deposition rate is affected by the arc width, and the deposition rate for small gauge wires can be increased by reducing the exit orifice spacing and wire electrode spacing (e.g., from about 2 mm to 1 mm).
[0032] The maximum spacing of the exit orifices and the maximum spacing of the wire electrodes is reached when the magnetic forces created by the current waveform (e.g., at peak current levels) still allow the formation of a bridging droplet, and is exceeded when a bridge is no longer possible. The minimum spacing is that which keeps the wires separated at the point where the bridge forms. The magnetic forces tend to pull the wire electrodes together, and the wires have some flexibility. Thus, the minimum spacing of the exit orifices and the minimum spacing of the wire electrodes depend on the stiffness of the electrodes, which is affected by parameters such as wire diameter, material of construction, etc.
[0033] FIG. 11 illustrates an end of an exemplary welding torch according to the present invention. The structure and operation of welding torches are generally known, and therefore the details of such structure and operation will not be detailed herein. As shown, the torch includes several components and is used to deliver at least two wire electrodes and a shielding gas to a workpiece in a welding or additive manufacturing operation. The torch includes a diffuser 205 that helps appropriately direct and distribute the shielding gas in a welding operation. Coupled to the downstream end of the diffuser 205 is a contact tip 200 that is used to deliver a welding current to at least two wire electrodes that pass through the contact tip simultaneously during welding. The contact tip 200 is configured to promote the formation of a bridge droplet between the wire electrodes that are routed through holes or channels in the contact tip. The bridge droplet bonds a first wire electrode to a second wire electrode before contacting a molten puddle created by a deposition operation, as described above.
[0034] An insulator 206 is screwed onto the outside of the diffuser 205. The insulator 206 electrically insulates the nozzle 204 from the current carrying components in the torch. The nozzle 204 directs the shielding gas from the diffuser 205 to the tip of the torch and then to the workpiece during welding.
[0035] Conventional contact tips have threads at the upstream or proximal end of the contact tip that screw into a diffuser. The contact tip and diffuser are connected by screwing the contact tip into the diffuser. Such a fastening system works well for welding with a single wire. The welding wire can be passed through the contact tip, and the contact tip can be rotated multiple times around the wire and screwed into the diffuser. However, when welding with multiple welding wires passing through the contact tip simultaneously, such a fastening system can cause undesirable twisting of the welding wire. For example, if two welding wires pass through the contact tip, threading the contact tip into the diffuser with multiple turns in succession that require more than 360° of rotation can cause the welding wire to twist and not be able to feed through the contact tip.
[0036] The contact tip 200 of FIG. 11 is attached to the spreader 205 by rotation of the contact tip less than 360°, such as 270° (3 / 4 turn), 180° (1 / 2 turn), 90° (1 / 4 turn), less than 90°, etc. The rotation of the contact tip 200 required to attach the contact tip to the spreader 205 can be any angle, preferably less than 360°, as desired, to ensure that the multiple wire electrodes passing through the contact tip are not excessively twisted during installation of the contact tip. If the welding wire is excessively twisted during installation of the contact tip, wire feeding problems can occur and the welding wire can become "tangled."
[0037] 11-16, the contact tip 200 is attached to the diffuser 205 by a quarter-turn clockwise of the contact tip within the diffuser. The contact tip 200 has a forward or downstream distal end that is tapered and includes a flat 215 for accommodating gripping by a tool such as pliers. The contact tip 200 is generally cylindrical, but has a rearward or upstream proximal end 208 that includes a radially projecting tab 210 that engages a slot 212 in the inner wall of the diffuser 205 to securely connect the contact tip to the diffuser. The rearward portion 208 of the contact tip 200 is disposed within the diffuser 205 when the contact tip is installed in the diffuser, and serves as the mounting shank for the contact tip. It can be seen that the diameter of the rearward portion 208 of the contact tip is smaller than the adjacent downstream portion, causing a shoulder 211 to project in a wavy direction from the cylindrical rearward portion 208 of the contact tip. The shoulder 211 seats against the terminating face of the diffuser 205 when the contact tip 200 is installed on the diffuser.
[0038] The contact tip 200 can be made from known contact tip materials and can be used with any known type of welding gun. The contact tip can include a conductive body, such as copper, extending from a rear proximal end to a forward distal end. As shown in this exemplary embodiment, the contact tip 200 has two separate wire channels or holes 214 and 216 that extend the length of the contact tip. The channels 214 / 216 can extend between a wire entry orifice at the proximal face of the mount shank 208 and a wire exit orifice at the distal face of the contact tip. During welding, a first wire electrode is fed through the first channel 214 and a second wire electrode is fed through the second channel 216. The channels 214 / 216 are typically sized appropriately for the diameter of the wire to be fed through the channels. For example, if the electrodes have the same diameter, the channels have the same diameter. However, if different wire sizes are used together, the channels should be sized appropriately to properly pass current through the different sized electrodes. Further, in the embodiment shown, the channels 214 / 216 are configured such that the electrodes exit the leading face of the contact tip 200 in a parallel relationship. However, in other exemplary embodiments, the channels can be configured such that the electrodes exit the leading face of the contact tip such that an angle in the range of + / - 15° exists between the centerlines of each electrode. The angle can be determined based on the desired performance characteristics of the welding operation. The example contact tips discussed herein are shown with two electrode holes. However, it should be understood that the contact tips can have holes for more than two electrodes, such as three or more holes.
[0039] A slot 212 in the inner wall of the diffuser 205 includes a shaft 218 and a helical portion 220. The shaft 218 of the slot 212 extends to the downstream termination face of the diffuser 205 against which the shoulder 211 of the contact tip 200 seats. After a welding electrode is fed through the contact tip 200, a radially projecting tab 210 on the mounting shank 208 is inserted into the shaft 218 of the slot 212 and the contact tip is forced into the diffuser 205. When the tab 210 reaches the helical portion 220 of the slot, the contact tip 200 rotates, moving the tab to the end of the helical portion. The helical portion 220 has a slight upstream pitch that draws the contact tip 200 inward as the contact tip rotates, so that the shoulder 211 of the contact tip seats against the downstream termination face of the diffuser 205. The tabs 210 of the mounting shank 208 can have tapered edges 217 that match the pitch of the slots 212 of the diffuser 205, thereby helping to ensure a tight connection between the two components. In the example embodiment shown, the helical portion 220 of the slots 212 allows the contact tip 200 to be secured to the diffuser 205 with a quarter turn of the contact tip. However, it should be understood that other rotation angles are possible (e.g., a quarter turn, more than or less than 90°). For example, the helical portion 220 of the slots can extend less than 360° around the inner circumference of the inner chamber of the diffuser 205.
[0040] 17 and 18 illustrate an example embodiment of a contact tip 200 that includes a biasing mechanism that provides an axial force between the contact tip and the diffuser 205. The biasing mechanism illustrated is a biasing spring 222, such as a wave washer. When the contact tip 200 is attached to the diffuser 205, the biasing spring 222 compresses to maintain an axial force between the contact tip and the diffuser. The axial force helps the radially protruding tabs 210 on the mounting shank 208 to seat in the slots 212 of the diffuser 205. In particular, the axial force can press the tapered surfaces of the tabs 210 against the side walls of the slots in the diffuser 205, thereby helping to secure the contact tip in place and less likely to come loose (e.g., due to thermal cycling, mechanical shock, etc.). The mounting shank 208 extends from a shoulder 211 of the contact tip 200, and the biasing spring 222 can be disposed annularly around the mounting shank between the radially protruding tabs and the shoulder. The bias spring 222 may be captured in the mount shank 208 such that it cannot be removed without damaging the bias spring or the contact tip. Various types of biasing mechanisms may be used to maintain an axial force between the contact tip 200 and the diffuser 205, such as, for example, a lock washer or a coil spring.
[0041] 19-24 show a further embodiment of a contact tip 302 and diffuser 300 for multi-wire welding or additive manufacturing. The contact tip 302 does not require rotation when installed in the diffuser 300, as described further below. The nozzle 204 and welding torch insulation 206 are generally similar to the embodiment of FIG. 7. The contact tip 302 also includes the wire channels 214 / 216 and shoulder 211, as described above.
[0042] The contact tip 302 and diffuser 300 are mated such that there is only one possible installation orientation between the contact tip and the diffuser. The inner surface 304 of the diffuser and the rear portion 306 of the contact tip or mounting shank are shown with corresponding flats that mate the diffuser and contact tip. However, other adjustment mechanisms can be used such as, for example, slot and protrusion adjustment mechanisms.
[0043] After the welding electrode passes through the contact tip 302, the contact tip is inserted axially into the diffuser 300 without twisting or rotating the contact tip. The diffuser 300 is a collet style that grips tightly on the rear portion 306 of the contact tip and holds it in place by friction. The diffuser 300 may include several slots 308, 310, 312 that allow the downstream end of the diffuser to expand slightly as the contact tip 302 is inserted into the diffuser. The expansion of the downstream end of the diffuser 300 applies a gripping force radially to the rear portion 306 of the contact tip. If desired, additional gripping mechanisms may be used to further secure the contact tip 302 within the diffuser 300. For example, a set screw may secure the contact tip to the diffuser or a clamp may further compress the downstream end of the diffuser around the rear portion of the contact tip. Such a clamp can be threaded onto the diffuser such that as the clamp is threaded onto the diffuser, the gripping force applied to the downstream end of the diffuser is provided by axial movement of the clamp.
[0044] Use of the embodiments described herein can provide significant improvements in stability, weld structure, and performance from known welding operations. However, in addition to welding operations, the embodiments can be used in additive manufacturing operations. Indeed, the system 100 described above can be used in additive manufacturing operations as well as welding operations. In exemplary embodiments, improved deposition rates can be achieved in additive manufacturing operations. For example, when using an STT type waveform in a single wire additive process, the use of a 0.045 inch wire can provide a deposition rate of about 5 lb / hr before becoming unstable. However, when using embodiments of the present invention and two 0.040 inch wires, a deposition rate of 7 lb / hr can be achieved with a stable transition. Since additive manufacturing processes and systems are known, the details thereof need not be described herein. In such processes, bridge currents such as those described above can be used in additive manufacturing current waveforms.
[0045] It should be noted that the exemplary embodiments are not limited to the use of the waveforms described above and herein, and other welding type waveforms may be used with embodiments of the present invention. For example, other embodiments may use variable polarity pulsed spray welding waveforms, AC waveforms, and the like, without departing from the spirit and scope of the present invention. For example, in variable polarity embodiments, the bridge portion of the welding waveform may be performed with negative polarity such that a bridge droplet is created while reducing the overall heat input to the weld puddle. For example, when using an AC type waveform, the waveform may have a frequency of 60 Hz to 200 Hz with alternating negative and positive pulses, thereby melting the two wires and forming a bridge droplet between the two wires. In further embodiments, the frequency may be within the range of 80 Hz to 120 Hz.
[0046] As previously described, embodiments of the present invention can be used with different types of consumables and consumable combinations, including flux-cored consumables. Indeed, embodiments of the present invention can provide a more stable welding operation when using flux-cored electrodes. In particular, the use of bridging droplets can help stabilize flux-cored droplets that may tend to be unstable in single-wire welding operations. Furthermore, embodiments of the present invention can increase welding and arc stability at higher deposition rates. For example, in single-wire welding operations, at high currents and high deposition rates, the droplet transfer type can change from streaming spray to rotating spray, which significantly reduces the stability of the welding operation. However, when using exemplary embodiments of the present invention, bridging droplets stabilize the droplets, greatly improving arc and weld stability at high deposition rates, such as above 20 lb / hr.
[0047] Additionally, as indicated above, consumables can be of different types and / or combinations to optimize a given welding operation. That is, the use of two different but compatible consumables can be combined to produce a desired weld joint. For example, compatible consumables include hardfacing wire, stainless wire, nickel alloys and steel wires of different compositions. As one specific example, a mild steel wire can be combined with an overalloyed wire to create a 309 stainless steel composition. This can be advantageous when one consumable of a desired type does not have the desired welding characteristics. For example, some consumables for specialty welding provide the desired weld chemistry but are extremely difficult to use and have problems providing a satisfactory weld. However, embodiments of the present invention allow the use of two consumables that are easier to weld and combine to create the desired weld chemistry. Embodiments of the present invention can be used to create alloy / deposition chemistries that are otherwise not commercially available or are otherwise very expensive to manufacture. Thus, two different consumables can be used to alleviate the need for expensive or unavailable consumables. Additionally, embodiments can be used to create dilute alloys. For example, the first welding wire can be a common, inexpensive alloy and the second welding wire can be a specialty wire. The desired deposition is the average of the two wires mixed well in the formation of a bridge droplet at a lower average cost of the two wires than the expensive specialty wire. Furthermore, in some applications, the desired deposition may not be obtained due to lack of suitable consumable chemistry, but can be reached by mixing two standard alloy wires that are mixed in a bridge droplet and deposited as a single droplet. Furthermore, in some applications, such as wear-resistant metal applications, the desired deposition may be a combination of tungsten carbide particles from one wire and chromium carbide particles from the other wire. In yet another application, a larger wire containing larger particles is mixed with a smaller wire containing fewer particles or smaller particles to deposit a mixture of the two wires. Here, the expected contribution from each wire is proportional to the size of the wire, given that the wire feed speed is the same.In yet another example, the wire feed speed of the wire is varied to vary the alloy produced based on the desired deposition, but intermixing of the wire is still produced by bridging droplets formed between the wires.
[0048] Although the present invention has been shown and described in detail with reference to exemplary embodiments thereof, the present invention is not limited to these embodiments. It will be apparent to those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention.
[0049] The following additional note is added: (Appendix 1) A welded or additively manufactured contact tip, A conductive body extending from a proximal end to a distal end of the body. The body comprises: a first bore terminating in a first exit orifice in a distal face of the body; a second bore terminating in a second exit orifice in the distal end face of the body; and Forming A welding or additive manufacturing contact tip, wherein the first exit orifice and the second exit orifice are separated from each other by a distance configured to promote formation of a bridge droplet between a first wire electrode fed through the first hole and a second wire electrode fed through the second hole during a deposition operation. (Supplementary Note 2) The welded or additively manufactured contact tip of Supplementary Note 1, wherein the first exit orifice has a diameter and the distance is within the range of 20% to 200% of the diameter. (Supplementary Note 3) The welded or additively manufactured contact tip of Supplementary Note 1, wherein the distance provides a spacing S between the first wire electrode and the second wire electrode that is within a range of 0.25 to 2.25 times the diameter of the first wire electrode and the second wire electrode measured between the nearest edges of the first wire electrode and the second wire electrode. (Appendix 4) The welded or additively manufactured contact tip of appendix 1, wherein the distance is less than 3 mm. (Appendix 5) The welded or additively manufactured contact tip of Appendix 1, wherein the body includes a mount shank, one or more inlet orifices are disposed in the mount shank, and the mount shank includes a radially protruding tab. (Supplementary Note 6) The welded or additively manufactured contact tip of Supplementary Note 5, further comprising a bias spring disposed between the radially protruding tab and the tip surface of the body. (Appendix 7) The welded or additively manufactured contact tip of Appendix 6, wherein the mount shank extends from a shoulder of the contact tip and the bias spring is annularly disposed around the mount shank between the shoulder and the radially protruding tab. (Appendix 8) The welded or additively manufactured contact tip of Appendix 7, wherein the radially protruding tab has a tapered edge and the bias spring is a wave washer. (Appendix 9) A welded or additively manufactured contact tip, A conductive body extending from a proximal end to a distal end of the body. The body comprises: a first bore through the body extending from a first inlet orifice at the proximal end of the body to a first outlet orifice at the distal end of the body; a second bore through the body extending from a second inlet orifice at the proximal end of the body to a second outlet orifice at the distal end of the body; Forming A welding or additive manufacturing contact tip, wherein the first exit orifice and the second exit orifice are separated from each other by a distance configured to promote formation of a bridge droplet between a first wire electrode fed through the first hole and a second wire electrode fed through the second hole during a deposition operation, the bridge droplet joining the first wire electrode to the second wire electrode before contacting a molten puddle created by the deposition operation. (Supplementary Note 10) The welded or additively manufactured contact tip of Supplementary Note 9, wherein the first exit orifice has a diameter and the distance is within the range of 20% to 200% of the diameter. (Supplementary Note 11) The welded or additively manufactured contact tip of Supplementary Note 9, wherein the distance provides a spacing S between the first wire electrode and the second wire electrode that is within a range of 0.25 to 2.25 times the diameter of the first wire electrode and the second wire electrode measured between the nearest edges of the first wire electrode and the second wire electrode. (Supplementary Note 12) The welded or additively manufactured contact tip of Supplementary Note 9, wherein the distance is less than 3 mm. (Appendix 13) The welded or additively manufactured contact tip of Appendix 9, wherein an angle between a centerline of the first wire electrode and a centerline of the second wire electrode is within the range of +15 degrees to -15 degrees when the first wire electrode exits the first exit orifice and when the second wire electrode exits the second exit orifice. (Appendix 14) The welded or additively manufactured contact tip of Appendix 9, wherein the body includes a mount shank, the first inlet orifice and the second inlet orifice are disposed in the mount shank, and the mount shank includes a radially protruding tab. (Supplementary Note 15) The welded or additively manufactured contact tip of Supplementary Note 14, further comprising a bias spring disposed between the radially protruding tab and the tip of the body. (Appendix 16) The welded or additively manufactured contact tip of Appendix 15, wherein the mount shank extends from a shoulder of the contact tip and the bias spring is annularly disposed around the mount shank between the shoulder and the radially protruding tab. (Supplementary Note 17) The welded or additively manufactured contact tip of Supplementary Note 16, wherein the radially protruding tab has a tapered edge and the bias spring is a wave washer. (Appendix 18) A welded or additively manufactured contact tip, A conductive body extending from a proximal end to a distal end of the body. The body comprises: a first channel terminating at a distal end surface of the body; a second channel terminating at the distal end surface of the body; Forming A welding or additive manufacturing contact tip, wherein at the distal end surface of the body, the first channel and the second channel are separated from each other by a distance configured to promote formation of a bridge droplet between a first wire electrode fed through the first channel and a second wire electrode fed through the second channel during a deposition operation, the bridge droplet coupling the first wire electrode to the second wire electrode before contacting a molten puddle created by the deposition operation. (Supplementary Note 19) A welded or additively manufactured contact tip as described in Supplementary Note 18, wherein the first channel has a diameter at the tip surface of the body and the distance is within the range of 20% to 200% of the diameter. (Supplementary Note 20) The welded or additively manufactured contact tip of Supplementary Note 18, wherein the distance provides a spacing S between the first wire electrode and the second wire electrode that is within a range of 0.25 to 2.25 times the diameter of the first wire electrode and the second wire electrode measured between the nearest edges of the first wire electrode and the second wire electrode. (Supplementary Note 21) The welded or additively manufactured contact tip of Supplementary Note 18, wherein the distance is less than 3 mm. (Addendum 22) The welded or additively manufactured contact tip of Addendum 18, wherein the body includes a mount shank, one or more inlet orifices are disposed in the mount shank, and the mount shank includes a radially protruding tab. (Supplementary Note 23) The welded or additively manufactured contact tip of Supplementary Note 22, further comprising a bias spring disposed between the radially protruding tab and the tip surface of the body. (Supplementary Note 24) The welded or additively manufactured contact tip of Supplementary Note 23, wherein the mount shank extends from a shoulder of the contact tip and the bias spring is annularly disposed around the mount shank between the shoulder and the radially protruding tab. 25. The welded or additively manufactured contact tip of claim 24, wherein the radially protruding tab has a tapered edge and the bias spring is a wave washer. [Explanation of symbols]
[0050] 100 Welding System 101, 103 Electrode source 105 Wire Feeder 107 Supply roller 109 Welding power source 111 Welding torch 113 Liner 120 Controller 200, 302 Contact Tip Channels 201, 203, 214, and 216 204 Nozzle 205, 300 Diffuser 206 Insulators 208 Mount Shank 210 Radial protruding tab 211 Shoulder 212, 308, 310, 312 Slots 215 Flat area 218 Shaft 220 Spiral part 222 Bias Spring 306 Rear part 600 Flowchart 700 Contact Tip 701, 702 Outlet orifice 710 Inlet Channel 711 First Exit Channel 712 Second Exit Channel 720 Separation part 800 waveforms 810 Background Current Level 820 Bridge Current Level 830 Peak Current Level 840 Spray Transfer Current Level 900 waveforms 910 Background part 920 Short Response Section 930, 1030 Bridge Current Levels 1000 Example Waveforms 1010 Background Level 1015 First Peak Level 1020 Second Peak Level E1, E2 electrode F Finger W Workpiece WB Weld bead
Claims
1. Welded or additively manufactured contact tip, The single conductive body comprises a single conductive body extending from the base end to the tip end of the single conductive body, the single conductive body having a mounting shank at the base end, one or more inlet orifices disposed on the mounting shank, the single conductive body further comprising a shoulder, the mounting shank extending from the shoulder and having a different diameter from the shoulder, and the single conductive body is The first hole ending at the tip, A second hole ending at the aforementioned tip, Forming, A welded or additively manufactured contact tip, wherein, during a deposition operation in which current is simultaneously flowed through the contact tip to both a first wire electrode sent through the first hole and a second wire electrode sent through the second hole, the solid portion of the first wire electrode sent through the first hole is prevented from coming into contact with the solid portion of the second wire electrode sent through the second hole, while the distance between the first wire electrode sent through the first hole and the second wire electrode sent through the second hole is configured to promote the formation of a bridge droplet between them.
2. The first hole extends to the tip of a first exit orifice, the second hole extends to the tip of a second exit orifice, the first exit orifice has a diameter, and the distance is in the range of 20% to 200% of the diameter. The welded or additively manufactured contact tip according to claim 1.
3. The distance provides a spacing between the first wire electrode and the second wire electrode that is within the range of 0.25 to 2.25 times the diameter of the first wire electrode and the second wire electrode, measured between the nearest edges of the first wire electrode and the second wire electrode. The welded or additively manufactured contact tip according to claim 1.
4. The distance is less than 3 mm. The welded or additively manufactured contact tip according to claim 1.
5. The mounting shank includes a radially protruding tab, The welded or additively manufactured contact tip according to claim 1.
6. The radially protruding tab has a tapered edge, The welded or additively manufactured contact tip according to claim 5.
7. A welded or additively manufactured contact chip, A single conductive body extending from a base end to a tip end, wherein the single conductive body has means for attaching a diffuser to the contact tip at the base end, one or more inlet orifices are located at the base end, the single conductive body further comprises a shoulder, the means for attaching the diffuser to the contact tip extends from the shoulder and has a different diameter from the shoulder, and the single conductive body is The first hole ending at the tip, A second hole ending at the aforementioned tip, Forming, At the tip portion, during a deposition operation in which current is simultaneously flowed through the contact tip to both the first wire electrode, which is sent through the first hole, and the second wire electrode, which is sent through the second hole, the first wire electrode, which is sent through the first hole, is separated from each other by a distance configured to promote the formation of a bridge droplet between them, while preventing the solid portion of the first wire electrode, which is sent through the first hole, from coming into contact with the solid portion of the second wire electrode, which is sent through the second hole. Welded or additively manufactured contact tips.
8. The first hole extends to the tip of a first exit orifice, the second hole extends to the tip of a second exit orifice, the first exit orifice has a diameter, and the distance is in the range of 20% to 200% of the diameter. The welded or additively manufactured contact tip according to claim 7.
9. The distance provides a spacing between the first wire electrode and the second wire electrode that is within the range of 0.25 to 2.25 times the diameter of the first wire electrode and the second wire electrode, measured between the nearest edges of the first wire electrode and the second wire electrode. The welded or additively manufactured contact tip according to claim 7.
10. The distance is less than 3 mm. The welded or additively manufactured contact tip according to claim 7.
11. The means for attaching the diffuser to the contact tip includes a radially protruding tab, The welded or additively manufactured contact tip according to claim 7.
12. The radially protruding tab has a tapered edge, The welded or additively manufactured contact tip according to claim 11.
13. The diameter is smaller than the diameter of the shoulder portion. The welded or additively manufactured contact tip according to claim 12.
14. The single conductive body further comprises a tapered tip portion and a flat portion for gripping by a tool, The welded or additively manufactured contact tip according to claim 13.
15. The shoulder portion is disposed between the radially protruding tab and the flat portion, The welded or additively manufactured contact tip according to claim 14.
16. The diameter of the mounting shank is smaller than the diameter of the shoulder portion. The welded or additively manufactured contact tip according to claim 6.
17. The single conductive body further comprises a tapered tip portion and a flat portion for gripping by a tool, The welded or additively manufactured contact tip according to claim 16.
18. The shoulder portion is disposed between the radially protruding tab and the flat portion, The welded or additively manufactured contact tip according to claim 17.