Project and Streaming Hybrid Pulse Welding

Abstract

To provide hybrid pulse welding using a projected spray transfer mode and a streaming spray transfer mode.SOLUTION: An arc welding or additive manufacturing system includes a wire feeder, a torch, a wire electrode driven through the torch by the wire feeder, and an arc generation power supply operatively connected to the torch to deliver a pulse waveform to the wire electrode during a deposition operation. The pulse waveform includes a series of current pulses and interleaved background current portions such that each current pulse is separated from a prior current pulse by a prior background current portion and separated from a subsequent current pulse by a subsequent background current portion. During each current pulse, a molten droplet is projected from a tip of the wire electrode followed by an axial spray of molten metal away from the tip of the wire electrode before the subsequent background current portion occurs.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority of U.S. Provisional Patent Application No. 63 / 129,810, filed on December 23, 2020, the disclosure of which is incorporated herein by reference.

[0002] The present invention relates to an arc welding operation for transferring molten metal from a wire electrode to a workpiece via spray transfer.

Background Art

[0003] In heavy - industry welding, such as welding plates and other workpieces with a thickness exceeding 0.25 inches, the welding puddle becomes large and the torch travel speed becomes slow. The productivity improvement has been evaluated due to the increased welding speed or the ease of making large welds at the conventional welding speed. In heavy industry, solid - wire gas metal arc welding (GMAW) is often used. As is common in heavy industry, although the size of the welding puddle is large, when the diameter of the arc cone converges, the puddle becomes unstable, tends to "swallow" the arc, and the liquid splashes (slosh).

Summary of the Invention

Problems to be Solved by the Invention

[0004] Semi-automatic GMAW welding using solid wire and mixed shielding gas can be performed with acceptable results up to approximately 16 pounds / hour (16 pounds per hour). Beyond 16 pounds / hour, the arc / paddle becomes unstable, potentially resulting in an unacceptable amount of spatter. To increase the arc cone size and improve paddle control, a larger welding wire is preferable. Operators often control large paddles by skillfully manipulating the arc (e.g., by weaving in some way). Metal-cored and flux-cored wires can further improve deposition rate and paddle control, but these alternatives result in higher fume rates, and in the case of flux-cored arc welding (FCAW), slag is generated, which must be removed later. It would be desirable to be able to perform solid-wire GMAW welding stably at deposition rates of 16 pounds / hour or higher while minimizing arc / paddle instability and spatter. [Means for solving the problem]

[0005] The following summary provides a simplified overview to enable a basic understanding of some aspects of the apparatus, systems, and / or methods described herein. This summary is not a comprehensive overview of the apparatus, systems, and / or methods described herein. This summary is not intended to identify or precisely describe the scope of any important elements of such apparatus, systems, and / or methods. The sole purpose of this summary is to present some concepts in a simplified form as an introduction to the more detailed explanations that will follow.

[0006] According to one aspect of the present invention, an arc welding or additive manufacturing system is provided. The arc welding or additive manufacturing system includes a wire feeder, a torch, a wire electrode driven through the torch by the wire feeder, and an arc generating power supply operably connected to the torch and delivering a pulse waveform to the wire electrode during welding. The pulse waveform includes a series of current pulses and interleaved background current portions such that each current pulse is separated from a preceding current pulse by a preceding background current portion and from a succeeding current pulse by a succeeding background current portion. Between each current pulse, a molten droplet is ejected from the tip of the wire electrode, followed by an axial spray of molten metal away from the tip of the wire electrode before the successive background current portion is generated.

[0007] According to another aspect of the present invention, an arc welding or additive manufacturing system is provided. The arc welding or additive manufacturing system includes a wire feeder, a torch, a wire electrode driven through the torch by the wire feeder, and an arc generating power supply operably connected to the torch to deliver a pulse waveform to the wire electrode during welding. The pulse waveform includes a series of current pulses and interleaved background current portions such that each current pulse is separated from a preceding current pulse by a preceding background current portion and from a succeeding current pulse by a succeeding background current portion. Between each current pulse, a molten droplet is ejected from the tip of the wire electrode, followed by either or both of a streaming spray and / or a rotating spray of molten metal, away from the tip of the wire electrode before the successing background current portion is generated.

[0008] According to another aspect of the present invention, an arc welding or additive manufacturing system is provided. The arc welding or additive manufacturing system includes a wire feeder, a torch, a wire electrode driven through the torch by the wire feeder, and an arc generating power supply operably connected to the torch to deliver a pulse waveform to the wire electrode during welding. The pulse waveform includes a series of current pulses separated by respective background current portions. Between each current pulse in the series of current pulses, molten metal is transferred from the wire electrode to the workpiece by a project spray transition mode and a subsequent second spray transition mode distinct from the project spray transition mode. During the project spray transition mode, molten droplets are ejected from the tip of the wire electrode toward the workpiece, and during the subsequent second spray transition mode, an axial spray of molten metal is performed from the tip of the wire electrode toward the workpiece before the next background current portion.

[0009] Those skilled in the art in the field relating to the present invention will be able to understand the above-described and other embodiments of the present invention by referring to the following accompanying drawings while reading the description below. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of the welding system. [Figure 2] This is a schematic diagram of the welding system. [Figure 3] This is a schematic diagram of the welding system. [Figure 4a] This shows the project spray transition mode during welding. [Figure 4b] This indicates the streaming spray transition mode or axial spray transition mode during welding. [Figure 4c] This shows the rotational spray transition mode during welding. [Figure 5a] This shows a portion of the welding work during the project transition. [Figure 5b] This shows a portion of the welding work during the project transition. [Figure 5c] This shows a portion of the welding work during the project transition. [Figure 6a] This shows a portion of the hybrid welding work involving project transition, streaming, and rotating spray transition. [Figure 6b] This shows a portion of the hybrid welding work involving project transition, streaming, and rotating spray transition. [Figure 6c] This shows a portion of the hybrid welding work involving project transition, streaming, and rotating spray transition. [Figure 6d] This shows a portion of the hybrid welding work involving project transition, streaming, and rotating spray transition. [Figure 6e] This shows a portion of the hybrid welding work involving project transition, streaming, and rotating spray transition. [Figure 7] An example of a welding waveform is shown. [Figure 8] Further examples of welding waveforms are shown. [Figure 9] An example of a controller is shown. [Modes for carrying out the invention]

[0011] The present invention relates to an arc welding operation in which molten metal is transferred from a wire electrode to a workpiece via spray transfer. In particular, the present invention relates to a hybrid pulse welding process in which molten metal is transferred to the workpiece via at least two different transfer modes between each current pulse. For example, between current pulses, molten droplets can be transferred to the workpiece via a project spray transfer mode, and subsequently, additional molten metal can be transferred via a streaming spray transfer mode or an axial spray transfer mode, and / or a rotating spray transfer mode.

[0012] Next, the present invention will be described with reference to the drawings. In the drawings, throughout, like reference numerals are used to refer to like elements. The various drawings are not necessarily drawn to scale, either from drawing to drawing or within a given drawing, and in particular, the sizes of the components are drawn in any size for ease of understanding the drawings. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, that the present invention may be practiced without these specific details. In addition, other embodiments of the present invention are possible and the present invention may be practiced and carried out in ways other than those described. The terms and expressions used in the description of the present invention are used for the purpose of facilitating understanding of the present invention and should not be construed as limiting.

[0013] As used herein, "at least one", "one or more", and "and / or" are open-ended expressions where the acts are conjunctive and disjunctive. For example, each of the expressions "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" means only A, only B, only C, A and B, A and C, B and C, or A, B, and C. In any of the description of embodiments, claims, or drawings, if there are disjunctive clauses representing two or more alternative terms, it should be understood that they are intended to encompass one of those terms, any of those terms, or both of those terms. For example, the clause "A or B" should be understood to encompass the possibilities of "A" or "B" or "A and B".

[0014] The embodiments of the present invention described herein are described in relation to gas metal arc welding (GMAW) systems, but other embodiments of the present invention are not limited thereto. For example, the embodiments can be used not only in flux-cored arc welding (FCAW) or metal-cored arc welding (MCAW) operations, but also in other similar types of welding operations. Furthermore, embodiments of the present invention can be used in manual, semi-automatic, and robotic welding operations. Embodiments of the present invention can also be used in welding-like metal welding operations such as additive manufacturing, hard build-up, and cladding. As used herein, the term “welding” is intended to encompass all these techniques, as all of these techniques involve material welding that either joins or constructs workpieces. Therefore, for efficiency, the term “welding” is used below in the description of exemplary embodiments, but is intended to include all of these material welding operations, regardless of whether joining multiple workpieces occurs.

[0015] Referring here to the drawings, Figure 1 shows an example of a GMAW welding system 100. The welding system 100 includes an arc generating power source such as a welding power source 102, a wire feeder 104, and a shielding gas supplyer 106. The welding power source 102 may include a power cable 108, a control cable 110, and an input power cable (not shown). The power cable 108 may include a grounding wire and clamp 112 connected to a workpiece 136, and a power cable 114 configured to connect to the wire feeder 104. The control cable 110 may be configured to connect to the wire feeder 104. In another embodiment (not shown), the control cable 110 may be replaced with a wireless communication link between the wire feeder 104 and the power source 102, and / or communication may be carried out via the power cable 114. It should be understood that the welding power source 102, power cable 108, and control cable 110 may have any configuration suitable for supplying power and controlling welding for the welding system 100. The power supply 102 further includes a user interface 105 that allows the user to observe and adjust various settings and parameters of the welding process (e.g., welding waveform parameters, voltage and / or current levels, wire feed speed, etc.). The user interface 105 can be located on the power supply 102, as shown in the figure, or it can be located at a location away from the power supply. In certain embodiments, the user interface 105 can be located on a remote processing device that communicates with the power supply 102, such as a networked computer, smartphone, or control pendant.

[0016] The wire feeding device 104 drives the welding wire electrode towards the workpiece 136 during arc welding or welding operations. As shown in FIG. 1, the wire feeding device 104 may include a housing 120, a gearbox 122, a wire spool assembly 124, and a user interface 126. Extending from the gearbox 122 is a hose 128 configured to connect to the welding torch or gun 130. The housing 120 may be connected to the user interface 126 and the gearbox 122. Further, a control cable 110 and a power cable 114 extending from the welding power source 102, and a pipe 116 extending from the shielding gas supply device 106 are configured to connect to the wire feeding device 104. The gearbox 122 includes at least a plurality of rollers that advance and optionally retract the welding wire electrode during the welding operation. It should be understood that the wire feeding device 104 may have any configuration suitable for receiving shielding gas, welding power from the power source 102, and welding control. In certain embodiments, the wire feeding device 104 may be directly attached to the welding power source 102.

[0017] Extending between the gearbox 122 and the welding torch 130 is the hose 128 which may include a power conductor, the wire electrode and, a wire conduit or liner, a gas line, and, a control cable for the torch trigger switch. The hose 128 can be of any diameter and length and is configured to include the wire electrode, the gas line, and the switch cable. The hose 128 is made of any material suitable for the welding environment. It should be understood that the hose 128 and the welding torch 130 may have any configuration suitable for supplying the welding wire electrode, shielding gas, and control through the hose and to the welding torch.

[0018] Figure 2 provides a schematic diagram of the arc welding system 100. A power supply 102 supplies a welding signal, or welding waveform, to the welding torch 130 and workpiece 136 through a power cable 108. The welding signal may have current and voltage, and may be a type of welding signal that requires a change in current from one level to another. For example, the signal may be a pulsed welding signal that changes from a background level to a peak level during welding, or an alternating polarity waveform that changes from one polarity to the other at a known rate. The current from the power supply 102 is delivered to the wire electrode 134 via a contact tip 148 to generate an arc 132 between the electrode 134 and the workpiece 136. As is common in GMAW welding operations, a positive power lead may be coupled to a wire feeder 104, which then delivers the welding current to the contact tip 148 through the welding cable in a hose 128. The power supply 102 may include terminals or output studs 115, 117 to connect the power cable 108 to the power supply's electrical output.

[0019] Figure 3 shows a schematic diagram of an example of a GMAW welding power supply 102. The power supply 102 can be configured to generate welding waveforms for various modes of metal transfer, such as short-circuit transfer (GMAW-S), surface tension transfer (STT), axial spray transfer, and pulsed spray transfer. In particular, the welding power supply 102 can generate pulsed welding waveforms for a hybrid pulsed welding process that transfers molten metal to the workpiece 136 via at least two different transfer modes between each current pulse. For example, molten droplets can be transferred to the workpiece via a projected spray transfer mode between current pulses, and additional molten metal can be transferred subsequently via a streaming spray transfer mode or an axial spray transfer mode, and / or a rotating spray transfer mode.

[0020] The welding power supply 102 is operably connected to the torch 130 and delivers a pulsed waveform to the wire electrode 134 during welding or other welding operations. The welding power supply 102 generates an electric arc 132 between the wire electrode 134 and the workpiece 136 to perform the welding operation. The welding power supply 102 receives electrical energy for generating the arc 132 from a power source 138, such as a commercial power supply or a generator. The power source 138 can be a single-phase or three-phase power source. In certain embodiments, the arc welding system can be a hybrid system including one or more batteries (not shown) that also supply energy to the welding power supply 102. The welding power supply 102 includes a switching-type power converter, such as an inverter 140, for generating the arc 132 according to a desired welding waveform. Alternatively, or in addition to this, the welding power supply 102 may also include a DC chopper (not shown) or a boost converter (not shown) for generating the welding waveform. AC power from power source 138 is rectified by input rectifier 142. The DC output from rectifier 142 is supplied to inverter 140. Inverter 140 supplies high-frequency AC power to transformer 144, and the transformer's output is converted back to DC by output rectifier 146. Output rectifier 146 supplies welding current to welding torch 130 which is operably connected to power supply 102 (e.g., via wire feeder). Torch 130 may have contact tip 148 for transmitting electrical energy supplied to wire electrode 134 by power supply 102.

[0021] The electrode 134 is a solid wire or cored consumable wire welding electrode. The electrode 134 can be fed from the spool 150 to the welding paddle by a wire feeder 104 configured to advance the electrode during welding. As schematically shown in Figure 3, the wire feeder 104 may include a motor-driven pinch roller for driving the wire electrode 134 through the torch 130.

[0022] The arc welding system can be configured for positive (DC+) or "reverse" polarity of the DC electrode, in which case the contact tip 148 and electrode 134 are connected to the positive lead wire from the power supply 102, and the workpiece 136 is connected to the negative lead wire. Alternatively, the arc welding system can be configured for negative (DC-) or "positive" polarity of the DC electrode, in which case the workpiece 136 is connected to the positive lead wire, and the contact tip 148 and electrode 134 are connected to the negative lead wire. Furthermore, the arc welding system can be configured for AC welding, in which an AC waveform is supplied to the contact tip 148, electrode 134, and workpiece 136.

[0023] The power supply 102 includes a controller 152 operably connected to an inverter 140 to control the welding waveform generated by the power supply. The controller 152 can control the output of the inverter 140 by supplying waveform control signals to the inverter 140. The controller 152 controls the output of the inverter 140 via the waveform control signals to achieve desired welding waveforms, welding voltages, welding currents, etc. The waveform control signals may include multiple separate control signals to control the operation of various switches (e.g., transistor switches) within the inverter 140. The power supply 102 further includes a user interface 105 that allows the user to observe and adjust various settings and parameters of the welding process (e.g., welding waveform parameters, voltage and / or current levels, wire feed rate, etc.). The controller 152 and the user interface 105 communicate bidirectionally to provide both user inputs and outputs at the user interface. The controller 152 monitors phases of the welding process via feedback signals. For example, a current sensor such as a current transformer (CT) or shunt 154 can supply a welding current feedback signal to the controller 152, and a voltage sensor 156 can supply a welding voltage feedback signal to the controller.

[0024] The controller 152 can be an electronic controller and may include a processor. The controller 152 may include one or more of the following: a microprocessor, microcontroller, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or discrete logic circuitry. The controller 152 may include a memory portion (e.g., RAM or ROM) that stores program instructions to provide the functions that the controller is considered to have in this specification. The controller 152 may include multiple physically separate circuits or electronic devices, such as a processor combined with separate comparators, logic circuits, etc. However, for ease of explanation, the controller 152 is shown as a monolithic device.

[0025] Figures 4a to 4c illustrate three different spray transition modes for welding operations. Figure 4a shows the project spray transition mode, Figure 4b shows the streaming or axial spray transition mode, and Figure 4c shows the rotating spray transition mode. In the project spray transition mode (Figure 4a), each current pulse exceeding the spray transition current level ejects a molten droplet from the tip of the wire electrode 134. The streaming or axial spray transition mode (Figure 4b) differs from the project spray transition mode in that a more constant flow of molten metal, rather than separate molten droplets, is ejected from the tip of the wire electrode 134 toward the workpiece 136. The rotating spray transition mode (Figure 4c) is similar to the streaming or axial spray transition mode, but with some rotation added to the flow of molten metal. Figures 5a to 5c further illustrate the project spray transition mode in a GMAW operation, which is a conventional pulsed welding operation. In Figure 5a, we can see that droplets 200 are growing at the end of the electrode 134. The current pulses transfer droplets 200 to the molten weld pool or paddle 202. The droplet transfer is shown in Figure 5b. As the current decreases from the pulse level to the background level, the molten material recedes towards the electrode 134, and a new droplet forms at the end of the electrode. In project spray transfer mode, one droplet is transferred with each current pulse. Figures 5a to 5c show that the arc 132 covers a relatively small percentage (e.g., less than 50%) of the surface of the weld pool 202. At high deposition rates (e.g., 16 pounds / hour), conventional pulse welding can result in a small, concentrated arc, which agitates and destabilizes the weld pool 202, which is undesirable.

[0026] The present invention employs a pulsed welding waveform. Between each current pulse, molten metal is transferred to the workpiece by projecting spray of molten droplets, followed by axial spray and / or rotating spray of molten metal. A hybrid pulsed welding process is obtained as a result of these two or three different spray transfer modes occurring consecutively during a single current pulse. Figures 6a to 6e illustrate a hybrid pulsed welding process using projecting spray transfer of molten metal (Figures 6a and 6b), followed by streaming or axial spray transfer (Figure 6c), and further followed by rotating spray transfer (Figure 6d). Hybrid transfer is a combination of at least two different metal transfer modes during a single current pulse. Hybrid transfer is achieved by using a pulsed welding waveform in which the peak current level and frequency, as well as the duration of the peak current portion of the waveform, are sufficient to eject molten droplets from the end of the electrode toward the welding zone, and during the peak current portion, streaming spray transfer and / or rotating spray transfer of molten metal follows the molten droplets. Given a high metal welding rate (e.g., 16 lbs / hour to 25 lbs / hour) and wire feed rate (e.g., 400 to 1000 inches / minute), the pulse waveform frequency of the present invention is slower than that of a conventional pulsed gas metal arc welding (GMAW-P) waveform, where only one droplet is transferred per pulse. For example, in a welding operation with a metal welding rate of approximately 16 lbs / hour, a conventional pulsed welding waveform may have a frequency in the range of 200 Hz to 400 Hz, whereas the waveform used in the hybrid pulsed welding process of the present invention is slower, with a frequency range of 120 Hz to 150 Hz.

[0027] Compared to the conventional heavy industry GMAW-P welding mode, where one droplet is transferred to the welding zone per pulse, the hybrid pulsed welding process shown in Figures 6a-6e uses a slower pulse rate or a longer pulse frequency. As a result, the concentration and width of the arc 132 are reduced, which leads to more uniform pressure on the weld pool 202, improved stability, and better control of the weld pool. In other words, the portion of the surface of the molten weld pool 202 covered by the arc 132 in the hybrid pulsed welding process is larger compared to the conventional pulsed welding process. Although a similar force will be applied to the weld pool 202 during welding in either process, this force is distributed over a wider area in the hybrid pulsed welding process. The lower pressure applied to the weld pool 202, combined with the slower pulse frequency, results in less agitation of the weld pool in the hybrid pulsed welding process than in the conventional pulsed welding process. This improves the stability of the welding process at high deposition rates. In addition, a slower pulse frequency in a hybrid pulse welding process is easier on the operator's senses, allowing them to slow down and perform precise, large welds.

[0028] After each current pulse of the hybrid pulse welding process, following a projecting spray of the molten droplet 200 followed by a streaming spray transfer or rotating spray transfer, the welding current is reduced to a background current level to stop the spray transfer and allow another molten droplet to grow on the end of the electrode 134. The metal is transferred by at least two different spray modes during each current pulse, namely, a large droplet by projecting mode, and immediately thereafter a smaller droplet by a smaller axial spray or rotating spray mode. The spray transfer is hindered by a periodic low-current background current portion that occurs immediately after each current pulse, interrupting the rotation of the molten metal before it becomes uncontrollable and unstable.

[0029] Figures 6a and 6b show the initial droplet being fired into the welding zone by a current pulse exceeding the spray transition current level. Figures 6c and 6d show axial and rotating spray transitions during the same current pulse. In Figure 6d, the molten flow 204 has just begun to rotate. As can be seen in Figure 6e, the background current portion of the welding waveform is hindering the axial / rotating spray transition. The background current level is lower than the spray transition current level, stopping the transfer of molten metal while maintaining the arc 132. At high deposition rates, some rotating spray transitions are possible, but this can lead to instability and spatter. However, rotating spray transitions can be controlled by limiting the duration of the peak current portion of the welding waveform after the droplet 200 has been fired into the welding zone.

[0030] The hybrid pulsed welding process shown in Figures 6a to 6e begins as a normal project droplet transfer, but by slowing the pulse frequency and increasing the degree to which the arc is dispersed across the surface of the weld pool compared to conventional pulsed welding, the droplet flow continues to transfer via axial spray and / or rotating spray. The hybrid pulsed welding process combines droplet transfer of the GMAW-P type transfer mode (large droplets) with an axial and / or rotating spray transfer mode using a single current pulse.

[0031] When the ratio of the surface area of ​​the weld pool 202 to the surface area of ​​the weld pool covered by the arc 132 approaches 1 (i.e., the arc area covering the weld pool is approximately equal to the size of the weld pool), the arc applies uniform pressure to the weld pool. The hybrid pulsed welding process shown in Figures 6a to 6e can expand the arc area to approximately the size of the weld pool 202, allowing for more uniform pressure applied to the weld pool compared to conventional GMAW-P operations. For example, the electric arc 132 from the wire electrode 134 can cover at least 80% (e.g., 80% to 100%) of the surface area of ​​the molten weld pool during the deposition process of hybrid pulsed welding. This can allow the operator to have better control over the weld pool. In conventional GMAW-P welding, when the ratio of the surface area of ​​the weld pool to the area covered by the arc exceeds 1 (e.g., the arc is substantially smaller than the size of the weld pool) and the deposition rate is high, the paddle tends to become turbulent, causing the liquid to splatter from side to side around the arc, becoming unstable and generating spatter. The degree to which the large arc cone 132 shown in Figures 6a to 6e agitates the weld pool 202 tends to be lower than that of the narrow arc cone used in conventional heavy industry GMAW-P welding.

[0032] Figure 7 shows examples of voltage waveforms 300 and current waveforms 302 for hybrid pulse welding, as well as voltage waveforms 304 and current waveforms 306 for conventional GMAW-P. It can be seen that the welding waveforms 300 and 302 of the hybrid pulse welding process have a peak voltage and current portion 308 and a background voltage and current portion 310. The background portion 310 may include a tailout from the peak current level to a preset background current level. The duration of the peak portion 308 and background portion 310 is significantly longer for the hybrid pulse welding waveforms 300 and 302 compared to the conventional pulse welding waveforms 304 and 306. As mentioned above, an example of the frequency range for the hybrid pulse welding waveform is 120Hz to 150Hz, but other frequencies below 120Hz and above 150Hz are also possible, and the deposition rate of the hybrid pulse welding process can exceed 16 pounds per hour.

[0033] The waveforms 300 and 302 of the hybrid pulsed welding are found to include a series of current pulses and interleaved background current portions such that each current pulse is separated from the preceding current pulse by a preceding background current portion and from the following current pulse by a following background current portion. Between each current pulse, a molten droplet is ejected from the tip of the wire electrode, followed by a streaming or axial spray of molten metal away from the tip of the wire electrode before the following background current portion occurs. Compared to conventional pulse waveforms 304 and 306, the hybrid pulsed welding waveforms 300 and 302, with their longer peak portion 308, generate an axial spray transition immediately following the project transition of the molten droplet between current pulses. Between each current pulse, before the next background current portion occurs, the molten metal is transferred from the wire electrode to the workpiece by a project spray transition mode and by a subsequent second spray transition mode (e.g., a streaming or axial spray transition mode, or a rotating spray transition mode) that is different from the project spray transition mode. The rotating spray transition mode can follow a streaming or axial spray transition mode during a current pulse. Therefore, between each current pulse, after the molten droplet is fired and before the subsequent background current portion occurs, either or both of the streaming / axial spray and rotating spray modes of the molten metal can follow, away from the tip of the wire electrode. In certain embodiments, the rotating spray mode of the molten metal follows the streaming / axial spray mode of the molten metal, during the current pulse and before the subsequent background current portion occurs. In such embodiments, three different transition modes occur between each current pulse (a streaming / axial spray transition mode followed by a projecting spray transition mode, and then a rotating spray transition mode).The subsequent or next background current portion following the current pulse stops the spray transition mode (e.g., stopping either the streaming / axial spray mode or the rotating spray mode), allowing droplets to build and push the wire electrode into position for the next transition cycle. The transition from the background current portion 310 to the current peak 308 may be slower in the waveforms 300, 302 of hybrid pulsed welding than in the waveforms 304, 306 of conventional pulsed welding. Droplet growth occurs both during the background portion 310 and during the transition to the current peak 308. During the transition to the current peak 308, the current is not sufficient to promote spray transition, but the wire electrode is heated significantly more than during the background portion 310. The ends of the wire electrode melt further during the transition to the current peak 308, and surface tension further increases the size of the molten droplet. Slowing down the rate of the transition from the background current portion 310 to the current peak 308 is desirable because it promotes the growth of larger droplets. At the current levels used in hybrid pulsed welding processes, project spray transition mode tends to be more stable than streaming / axial or rotating spray transition mode, so it may be desirable to make the droplets formed for project spray transition mode larger.

[0034] As mentioned above, compared to the arc generated in conventional GMAW-P operations, the hybrid pulse waveform generates a larger arc area across the entire weld pool. A larger arc area makes it easier to handle on the molten weld pool at high deposition rates (e.g., 16 pounds / hour or more). The waveform of conventional GMAW-P pulse welding generates a highly concentrated arc with a small, short arc length at such high deposition rates. When conventional GMAW-P welding is performed above approximately 16 pounds / hour, the depression formed in the weld paddle becomes excessive, the weld pool attempts to engulf the arc until it is almost completely buried, and the weld paddle begins to destabilize as the liquid metal (weld pool) splashes from side to side. The hybrid pulse welding process described above can reduce agitation and instability of the molten weld pool by increasing the arc size and thereby applying more uniform pressure across the entire weld pool. In addition, slower pulse frequencies used in hybrid pulse welding processes are easier on the operator's senses (e.g., visual and / or auditory), allowing them to slow down and perform large, precise welds.

[0035] Figure 8 shows further examples of voltage waveforms 312 and current waveforms 314 for hybrid pulse welding to perform hybrid metal transfer. The high-peak current portion 316 has a peak current level greater than 600 A. The high-peak current portion 316 causes molten droplets to be ejected from the tip of the wire electrode toward the welding zone of the workpiece. A second, low-peak current portion 318 (e.g., about 400 A) follows the high-peak current portion. The second peak current portion 318 provides a spray current level lower than that of the peak current portion 316. The second peak current portion 318 results in either or both streaming spray and rotating spray of molten metal toward the welding zone. A background current portion 320 with a current level less than 300 A follows the second peak current portion 318. The background current portion 320 may include a tailout from the spray current level of the second peak current portion 318 toward a preset background current level. The background current portion 320 stops the spray transfer that is occurring during the second peak current portion 318, allowing droplets to form and push the wire electrode into position for the next transfer cycle.

[0036] Figure 9 illustrates an exemplary embodiment of a controller 152, which is operably connected to a power supply and controls an output current waveform. The controller 152 includes at least one processor 414 capable of communicating with a number of peripheral devices via a bus subsystem 412. These peripheral devices may include, for example, a storage subsystem 424 including a memory subsystem 428 and a file storage subsystem 426, a user interface input device 422, a user interface output device 420, and a network interface subsystem 416. The input and output devices enable user interaction with the controller 152. The network interface subsystem 416 provides an interface to an external network and is coupled to a corresponding interface device in another computer system.

[0037] The user interface input device 422 may include a keyboard, a pointing device such as a mouse, trackball, touchpad, or graphics tablet, a scanner, a touchscreen integrated into a display, an audio input device such as a speech recognition system, a microphone, and / or other types of input devices. In general, the use of the term “input device” is intended to include all possible types of devices and methods for inputting information into the controller 152 or onto a communication network.

[0038] The user interface output device 420 may include a display subsystem or a non-visual display such as an audio output device. The display subsystem may include a flat panel device such as a cathode ray tube (CRT), liquid crystal display (LCD), projection device, or any other mechanism for creating a visible image. The display subsystem may also provide a non-visual display, such as via an audio output device. Generally, the use of the term “output device” is intended to include all possible types of devices and methods for outputting information from the controller 152 to the user or to another machine or computer system.

[0039] The storage subsystem 424 provides a non-temporary computer-readable storage medium for storing programming and data structures that provide some or all of the functionality of the control algorithms and software modules described herein. These software modules are generally executed by the processor 414 alone or in combination with other processors. The memory 428 used within the storage subsystem may include multiple memories, including a main random access memory (RAM) 430 for storing instructions and data during program execution, and a read-only memory (ROM) 432 for storing fixed instructions. The file storage subsystem 426 can provide persistent storage for program and data files and may include a hard disk drive, flash memory, a floppy disk drive, a CD-ROM drive, an optical drive, or a removable media cartridge, including associated removable media. Modules implementing the functionality of a particular embodiment may be stored by the file storage subsystem 426 within the storage subsystem 424, or by other machines accessible by the processor 414.

[0040] The bus subsystem 412 provides a mechanism for various components and subsystems of the controller 152 to communicate with each other as intended. Although the bus subsystem 412 is schematically shown as a single bus, alternative embodiments of the bus subsystem may use multiple buses.

[0041] Numerous other controller configurations 152 are possible, some with more or fewer components than the controller depicted in Figure 9.

[0042] Naturally, this disclosure is illustrative, and various modifications can be made by adding, modifying, or deleting details without departing from the fair scope of the teachings contained herein. Therefore, the present invention is not limited to the specific details of this disclosure, except to the extent to which the following claims are necessarily limited in this way. [Explanation of Symbols]

[0043] 100 welding systems 102 Welding Power Supply 104 Wire feeder 105 User Interface 106 Shielding gas supply device 108, 114 Power Cables 110 Control Cable 112 Grounding wire and clamp 115, 117 terminals or output studs 116 pipes 120 Housing 122 Gearbox 124 Wire Spool Assembly 126 User Interface 128 Hose 130 Welding Torch 132 Arc 134 Wire electrodes 136 Workpieces 138 Power Source 140 Inverter 142 Input Rectifier 144 Transformer 146 Output Rectifier 148 Contact Tips 150 spool 152 Controllers 154 Current Sensor 156 Voltage Sensor 200 droplets 202 Welding Pool 204 Molten flow 300 Hybrid pulse welding voltage waveforms 302 Current waveform for hybrid pulse welding 304 Voltage waveform of the conventional GMAW-P 306 Current waveform of the conventional GMAW-P 308 Peak section 310 Background section 312 Voltage waveform of hybrid pulse welding 314 Current waveform for hybrid pulse welding 316 High Peak Current Section 318 Low-peak current portion 320 Background current section 412 Bus subsystem 414 processors 416 Network Interface Subsystem 420 User Interface Output Device 422 User Interface Input Device 424 Storage Subsystems 426 File Storage Subsystem 428 Memory subsystems 430 Random Access Memory 432 Read-only memory

Claims

1. Arc welding or additive manufacturing system, Wire feeding device and Torch and, A wire electrode driven through the torch by the wire feeding device, An arc generating power supply, which is operably connected to the torch and delivers a pulse waveform to the wire electrode during welding, Includes, An arc welding or additive manufacturing system wherein the pulse waveform comprises a series of current pulses and interleaved background current portions such that each current pulse is separated from a preceding current pulse by a preceding background current portion and from a succeeding current pulse by a succeeding background current portion, and between each current pulse, a molten droplet is ejected from the tip of the wire electrode, followed by an axial spray of molten metal away from the tip of the wire electrode before the succeeding background current portion is generated.

2. The arc welding or additive manufacturing system according to claim 1, wherein the subsequent background current portion stops the axial spray of the molten metal.

3. The arc welding or additive manufacturing system according to claim 2, wherein each current pulse includes a peak current level that causes the molten droplet to be ejected from the tip of the wire electrode and a spray current level in which the axial spray of the molten metal is carried out between them, the spray current level being less than the peak current level.

4. The arc welding or additive manufacturing system according to claim 1, wherein a rotating spray transfer of the molten metal follows the axial spray of the molten metal and before the subsequent background current portion is generated.

5. The arc welding or additive manufacturing system according to claim 4, wherein the subsequent background current portion stops the rotational spray transfer of the molten metal.

6. The arc welding or additive manufacturing system according to claim 1, wherein the frequency of the pulse waveform is in the range of 120 Hz to 150 Hz, and the welding speed of the welding operation is greater than 16 pounds (7.26 kg) per hour.

7. The arc welding or additive manufacturing system according to claim 6, wherein the electric arc from the wire electrode covers at least 80% of the surface area of ​​the molten welding pool during the welding operation.

8. Arc welding or additive manufacturing system, Wire feeding device and Torch and, A wire electrode driven through the torch by the wire feeding device, An arc generating power supply, which is operably connected to the torch and delivers a pulse waveform to the wire electrode during welding, Includes, The pulse waveform includes a series of current pulses and interleaved background current portions such that each current pulse is separated from the preceding current pulse by a preceding background current portion and from the following current pulse by a following background current portion, between each current pulse, a molten droplet is ejected from the tip of the wire electrode, and thereafter, before the following background current portion occurs, one or both of the molten metal are followed by a streaming spray and / or a rotating spray away from the tip of the wire electrode. An arc welding or additive manufacturing system in which each current pulse includes a peak current level that causes the molten droplet to be ejected from the tip of the wire electrode, and a spray current level during which one or both of the streaming spray and / or rotating spray of the molten metal are performed, wherein the spray current level is less than the peak current level.

9. The arc welding or additive manufacturing system according to claim 8, wherein the subsequent background current portion stops one of the streaming spray and the rotating spray of the molten metal.

10. The arc welding or additive manufacturing system according to claim 8, wherein the rotating spray of molten metal follows the streaming spray before the subsequent background current portion is generated.

11. The arc welding or additive manufacturing system according to claim 10, wherein the subsequent background current portion stops the rotational spray of the molten metal.

12. The arc welding or additive manufacturing system according to claim 8, wherein the frequency of the pulse waveform is in the range of 120 Hz to 150 Hz, and the welding speed of the welding operation is greater than 16 pounds (7.26 kg) per hour.

13. The arc welding or additive manufacturing system according to claim 12, wherein the electric arc from the wire electrode covers at least 80% of the surface area of ​​the molten welding pool during the welding operation.

14. Arc welding or additive manufacturing system, Wire feeding device and Torch and, A wire electrode driven through the torch by the wire feeding device, An arc generating power supply, which is operably connected to the torch and delivers a pulse waveform to the wire electrode during welding, Includes, An arc welding or additive manufacturing system wherein the pulse waveform includes a series of current pulses separated by respective background current portions, and between each current pulse of the series of current pulses, molten metal is transferred from the wire electrode to the workpiece by a project spray transition mode and a subsequent second spray transition mode different from the project spray transition mode, during the project spray transition mode, molten droplets are ejected from the tip of the wire electrode toward the workpiece, and during the subsequent second spray transition mode, axial spraying of molten metal is performed from the tip of the wire electrode toward the workpiece before the next background current portion.

15. The arc welding or additive manufacturing system according to claim 14, wherein the subsequent background current portion stops the axial spray of the molten metal.

16. The arc welding or additive manufacturing system according to claim 15, wherein each current pulse includes a peak current level that causes the molten droplet to be ejected from the tip of the wire electrode and a low current level in which the axial spray of the molten metal takes place, the low current level being less than the peak current level.

17. The arc welding or additive manufacturing system according to claim 14, wherein the axial spray of molten metal is followed by the project spray transition mode and a third spray transition mode different from the second spray transition mode, and during the third spray transition mode, before the next background current portion, a rotational spray of molten metal is performed from the tip of the wire electrode toward the workpiece.

18. The arc welding or additive manufacturing system according to claim 17, wherein the subsequent background current portion stops the rotational spray of the molten metal.

19. The arc welding or additive manufacturing system according to claim 14, wherein the frequency of the pulse waveform is in the range of 120 Hz to 150 Hz, and the welding speed of the welding operation is greater than 16 pounds (7.26 kg) per hour.

20. The arc welding or additive manufacturing system according to claim 19, wherein the electric arc from the wire electrode covers at least 80% of the surface area of ​​the molten welding pool during the welding operation.

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