Hybrid injection and flow pulse welding

Abstract

An arc welding or additive manufacturing system, comprising: a wire feeder; a welding torch; a wire electrode driven through the welding torch by the wire feeder; and an arc generation power supply operatively connected to the welding torch to deliver a pulse waveform to the wire electrode during a cladding operation. The pulse waveform includes a series of current pulses and staggered base current portions, such that each current pulse is separated from a previous current pulse by a previous base current portion and from a subsequent current pulse by a subsequent base current portion. During each current pulse, a molten droplet is ejected from a tip of the wire electrode before the subsequent base current portion occurs, followed by an axial ejection of molten metal away from the tip of the wire electrode.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 129,810 filed on December 23, 2020, the disclosure of which is incorporated herein by reference. Background of the Invention Technical Field

[0004] The present invention relates to arc welding operations in which molten metal is transferred from a wire electrode to a workpiece via spray transfer. Background Art

[0006] Heavy fabrication welding (such as welding plates and other workpieces greater than 0.25 inches thick) involves large weld pools and slow torch travel speeds. Increased productivity is measured by higher deposition rates or the increased ease of making larger welds at conventional deposition rates. Typically, solid wire gas metal arc welding (GMAW) is used for heavy fabrication. When the weld pool size is large (common in heavy fabrication) but the arc cone diameter is concentrated, the weld pool will become unstable and will try to "eat" the arc and tend to slosh.

[0007] Semi-automatic GMAW welding operations can be performed using solid wire and mixed shielding gas with acceptable results up to 16 lb / hr (pounds per hour). In the case of exceeding 16 lb / hr, unacceptable amounts of spatter may be generated due to arc / molten pool instability. In order to increase the size of the arc cone to improve the molten pool control, larger wires are preferred. Operators typically manipulate the arc (e.g., weave it in a certain way) to control a larger molten pool. Metal-cored wires and flux-cored wires can be used to further increase the deposition rate and molten pool control, but these alternatives result in higher smoke rates and, in the case of flux-cored arc welding (FCAW), produce slag that must be chopped off later. It would be desirable to stably perform solid wire GMAW welding at deposition rates equal to or exceeding 16 lb / hr while minimizing arc / molten pool instability and spatter. Summary of the invention

[0008] The following summary of the invention presents a simplified overview to provide a basic understanding of some aspects of the devices, systems and / or methods discussed herein. The present summary is not an extensive review of the devices, systems and / or methods discussed herein. It is not intended to point out key elements or to delimit the scope of such devices, systems and / or methods. The only purpose is to present some concepts in a simplified form as a preface to a more detailed description presented later.

[0009] 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 welding torch; a wire electrode, which is driven through the welding torch by the wire feeder; and an arc generation power supply device, which is operatively connected to the welding torch to deliver a pulse waveform to the welding wire electrode during a cladding operation. The pulse waveform includes a series of current pulses and staggered base current portions, so that each current pulse is separated from the previous current pulse by the previous base current portion and separated from the subsequent current pulse by the subsequent base current portion. During each current pulse, before the subsequent base current portion occurs, a molten droplet is ejected from the end of the welding wire electrode, followed by an axial ejection of molten metal away from the end of the welding wire electrode.

[0010] 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 welding torch; a wire electrode, which is driven through the welding torch by the wire feeder; and an arc generation power supply device, which is operatively connected to the welding torch to deliver a pulse waveform to the welding wire electrode during a cladding operation. The pulse waveform includes a series of current pulses and staggered base current portions, so that each current pulse is separated from the previous current pulse by the previous base current portion and separated from the subsequent current pulse by the subsequent base current portion. During each current pulse, before the subsequent base current portion occurs, a molten droplet is ejected from the end of the welding wire electrode, followed by one or both of a stream jet and a rotational jet of molten metal away from the end of the welding wire electrode.

[0011] 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 welding torch; a wire electrode, which is driven through the welding torch by the wire feeder; and an arc generation power supply device, which is operatively connected to the welding torch to deliver a pulse waveform to the welding wire electrode during a cladding operation. The pulse waveform includes a series of current pulses separated by corresponding base current portions. During each current pulse in the series of current pulses, molten metal is transferred from the welding wire electrode to a workpiece through a projected spray transfer mode and a subsequent second spray transfer mode different from the projected spray transfer mode. During the projected spray transfer mode, molten droplets are ejected from the tip of the welding wire electrode toward the workpiece, and during the subsequent second spray transfer mode, axial ejection of molten metal from the tip of the welding wire electrode toward the workpiece occurs before the next base current portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above and other aspects of the present invention will become apparent to those skilled in the art to which the present invention relates after reading the following description with reference to the accompanying drawings, in which:

[0013] Figure 1 It is a three-dimensional diagram of the welding system;

[0014] Figure 2 is a schematic diagram of the welding system;

[0015] Figure 3 is a schematic diagram of the welding system;

[0016] FIG4 a shows a jet spray transfer pattern during a welding operation;

[0017] FIG4 b shows a streaming or axial spray transfer pattern during a welding operation;

[0018] FIG4 c shows a rotary spray transfer pattern during a welding operation;

[0019] FIG5 a shows a portion of an injection transfer welding operation;

[0020] FIG5 b shows a portion of an injection transfer welding operation;

[0021] FIG5 c shows a portion of an injection transfer welding operation;

[0022] Fig. 6a shows a portion of a hybrid shot transfer, stream and rotary spray welding operation;

[0023] Fig. 6b shows a portion of a hybrid shot transfer, stream and rotary spray welding operation;

[0024] Fig. 6c shows a portion of a hybrid shot transfer, stream and rotary spray welding operation;

[0025] Fig. 6d shows a portion of a hybrid shot transfer, stream and rotary spray welding operation;

[0026] Fig. 6e shows a portion of a hybrid shot transfer, stream and rotary spray welding operation;

[0027] Figure 7 An example welding waveform is shown;

[0028] Figure 8 Additional example welding waveforms are shown; and

[0029] Fig. 9 An example controller is shown. DETAILED DESCRIPTION

[0030] The present invention relates to arc welding operations that transfer molten metal from a wire electrode to a workpiece via spray transfer. In particular, the present invention relates to a hybrid pulse welding process that transfers molten metal to the workpiece via at least two different transfer modes during each current pulse. For example, during the current pulse, molten droplets may be delivered to the workpiece via an ejection-type spray transfer mode, and the ejection-type spray transfer mode may be followed by additional molten metal transfer via a stream or axial spray transfer mode and / or a rotational spray transfer mode.

[0031] The present invention will now be described with reference to the accompanying drawings, wherein the same reference numerals are used to refer to the same elements throughout the text. It will be understood that these different drawings do not have to be drawn in a proportional manner to each other, and this is also true within a given drawing, and in particular, the size of the parts is drawn arbitrarily, for the convenience of understanding the drawings. In the following description, for the purpose of explanation, a plurality of specific details are set forth in order to provide a comprehensive understanding of the present invention. However, it may be apparent that the present invention can be practiced without these specific details. In addition, other embodiments of the present invention are possible and can be practiced and implemented in a manner other than as described. The terms and phrases used in describing the present invention are adopted for the purpose of promoting understanding of the present invention and should not be considered restrictive.

[0032] As used herein, "at least one," "one or more," and "and / or" are open expressions that are both conjunctive and disjunctive in operation. 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" refers to A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B, and C together. Any disjunctive words and / or phrases that give two or more alternative terms, whether in the description of the embodiments, claims, or drawings, should be understood to cover the following possibilities: including one of these terms, any of these terms, or all of the terms. For example, the phrase "A or B" should be understood to include the following possibilities: "A," or "B," or "A and B."

[0033] Although the embodiments of the present invention described herein are discussed in the context of a gas shielded metal arc welding (GMAW) system, other embodiments of the present invention are not limited thereto. For example, the embodiments may be used in flux cored arc welding (FCAW) or metal cored arc welding (MCAW) welding operations and other similar types of deposition operations. Further, embodiments of the present invention may be used in manual, semi-automatic, and robotic welding operations. Embodiments of the present invention may also be used in metal deposition operations similar to welding, such as additive manufacturing, hardfacing, and plating. As used herein, the term "welding" is intended to encompass all of these techniques, as all of these techniques involve the deposition of materials used to combine or construct workpieces. Therefore, for efficiency, the term "welding" is used below to describe exemplary embodiments, but is intended to include all of these material deposition operations, whether or not multiple workpieces are combined together.

[0034] Referring now to the accompanying drawings, Figure 1 An example GMAW welding system 100 is shown. The welding system 100 includes an arc generating power supply (such as a welding power supply 102), a wire feeder 104, and a shielding gas supply 106. The welding power supply 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 ground wire and a clamp 112 connected to a workpiece 136, and a power cable 114 configured to be connected to the wire feeder 104. The control cable 110 may be configured to be connected 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 supply 102 and / or communication may occur via the power cable 114. It should be understood that the welding power supply 102, the power cable 108, and the control cable 110 may have any configuration suitable for supplying power and welding control to the welding system 100. The power supply 102 further includes a user interface 105 through which a user can view 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, or remote from the power supply. In some 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, a smart phone, a control pendant, etc.

[0035] During an arc welding or cladding operation, the wire feeder 104 drives the wire electrode toward the workpiece 136. Figure 1As shown in , the wire feeder 104 may include a housing 120, a gearbox 122, a wire spool assembly 124, and a user interface 126. A hose 128 extends from the gearbox 122, which is configured to be connected to a welding torch or welding gun 130. The housing 120 may be connected to the user interface 126 and the gearbox 122. In addition, the control cable 110 and the power cable 114 extending from the welding power supply 102 and the tube 116 extending from the shielding gas supply 106 are configured to be connected to the wire feeder 104. The gearbox 122 includes at least a plurality of rollers that advance and optionally retract the wire electrode during the cladding operation. It should be understood that the wire feeder 104 may have any configuration suitable for receiving shielding gas, welding power from the power supply 102, and welding control. In some embodiments, the wire feeder 104 may be directly attached to the welding power supply 102.

[0036] A hose 128 extends between the gearbox 122 and the welding torch 130, which can accommodate power conductors, wire electrodes and wire conduits or liners, gas lines, and control cables for the torch trigger switch. The hose 128 can be any diameter and length configured to accommodate the wire electrodes, gas lines, and switch cables. 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 can have any configuration suitable for supplying the wire electrode, shielding gas, and controls to the welding torch through the hose.

[0037] Figure 2 A schematic diagram of an arc welding system 100 is provided. A power supply 102 provides a welding signal or welding waveform to a welding torch 130 and a workpiece 136 via a power cable 108. The welding signal has a current and a voltage, and may be a type of welding signal that requires the current to change from one level to another. For example, the signal may be a pulsed welding signal that changes from a base value to a peak level during welding, or an alternating polarity waveform that changes from one polarity to another at a known rate. 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 140, which then delivers the welding current to the contact tip 148 via a welding cable in a hose 128. The power supply 102 may include terminals or output terminals 115, 117 that connect the power cable 108 to the power output of the power supply.

[0038] Figure 3A schematic diagram of an example GMAW welding power supply 102 is shown. The power supply 102 can be configured to generate welding waveforms for various metal transfer modes, 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 a pulsed welding waveform for a hybrid pulse welding process that transfers molten metal to the workpiece 136 via at least two different transfer modes during each current pulse. For example, during the current pulse, molten droplets can be transported to the workpiece via an ejection spray transfer mode, and the ejection spray transfer mode can be followed by additional molten metal transfer via a stream or axial spray transfer mode and / or a rotary spray transfer mode.

[0039] The welding power supply 102 is operatively connected to the welding torch 130 to deliver a pulse waveform to the wire electrode 134 during welding or other cladding operations. The welding power supply 102 generates an arc 132 between the wire electrode 134 and the workpiece 136 to perform the cladding operation. The welding power supply 102 receives electrical energy for generating the arc 132 from a power supply 138 (such as a commercial power supply or a generator). The power supply 138 can be a single-phase or three-phase power supply. In some 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 power converter (such as an inverter 140) for generating the arc 132 according to the desired welding waveform. Alternatively or additionally, the welding power supply 102 may include a DC chopper (not shown) or a boost converter (not shown) for generating the welding waveform. The AC power from the power supply 138 is rectified by an input rectifier 142. The DC output from the rectifier 142 is supplied to the inverter 140. The inverter 140 supplies high frequency AC power to the transformer 144, and the output of the transformer is converted back to DC by the output rectifier 146. The output rectifier 146 supplies welding current to the welding torch 130, which is operatively connected to the power supply 102 (e.g., via a wire feeder). The welding torch 130 may have a contact tip 148 for transmitting the electrical energy supplied by the power supply 102 to the wire electrode 134.

[0040] The electrode 134 is a solid or cored consumable wire welding electrode. The electrode 134 may be fed from a spool 150 by a wire feeder 104 configured to advance the electrode toward the weld pool during a welding operation. Figure 3 As schematically shown in FIG. 1 , the wire feeder 104 may include powered pinch rollers for driving the wire electrode 134 through the welding torch 130 .

[0041] The arc welding system can be configured for direct current electrode positive polarity (DC+) or "reverse" polarity, wherein the contact tip 148 and electrode 134 are connected to the positive lead from the power supply 102, and the workpiece 136 is connected to the negative lead. Alternatively, the arc welding system can be configured for direct current electrode negative polarity (DC-) or "straight" polarity, wherein the workpiece 136 is connected to the positive lead, and the contact tip 148 and electrode 134 are connected to the negative lead. Further, the arc welding system can be configured for AC welding, in which an AC waveform is provided to the contact tip 148, electrode 134, and workpiece 136.

[0042] The power supply 102 includes a controller 152 operatively connected to the inverter 140 to control the welding waveform generated by the power supply. The controller 152 may provide a waveform control signal to the inverter 140 to control the output of the inverter. The controller 152 controls the output of the inverter 140 via the waveform control signal to achieve a desired welding waveform, welding voltage, welding current, etc. The waveform control signal may include a plurality of separate control signals for controlling the operation of various switches (e.g., transistor switches) within the inverter 140. The power supply 102 further includes a user interface 105 through which a user may view 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 controller 152 communicates bidirectionally with the user interface 105 to provide both user input and user output at the user interface. The controller 152 monitors various aspects of the welding process via feedback signals. For example, a current sensor, such as a current transformer (CT) or shunt 154, may provide a welding current feedback signal to the controller 152, and a voltage sensor 156 may provide a welding voltage feedback signal to the controller.

[0043] Controller 152 can be an electronic controller and can include a processor. Controller 152 can include one or more of a microprocessor, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a discrete logic circuit system, etc. Controller 152 can include a memory portion (e.g., RAM or ROM) that stores program instructions that cause the controller to provide the functions assigned to it herein. Controller 152 can include multiple physically separated circuits or electronic devices, such as a processor combined with a separate comparator, a logic circuit, etc. However, for ease of explanation, controller 152 is shown as a single device.

[0044] Figures 4a to 4c illustrate three different spray transfer modes for cladding operations. Figure 4a shows an ejection spray transfer mode, Figure 4b shows a stream or axial spray transfer mode, and Figure 4c shows a rotational spray transfer mode. In the ejection spray transfer mode (Figure 4a), molten droplets are ejected from the tip of the wire electrode 134 by corresponding current pulses that exceed the jet transition transition current level. The stream or axial spray transfer mode (Figure 4b) differs from the ejection spray transfer mode in that a more constant stream of molten metal rather than different molten droplets is ejected from the tip of the wire electrode 134 toward the workpiece 136. The rotational spray transfer mode (Figure 4c) is similar to the stream or axial spray transfer mode, but adds some rotation imparted to the molten metal stream. Figures 5a to 5c further illustrate an ejection spray transfer mode for conventional pulse welding, GMAW operation. Droplets 200 growing on the end of the electrode 134 can be seen in Figure 5a. The current pulse transitions the droplets 200 to a molten weld pool or molten pool 202. The transition of the droplets is shown in FIG5b. As the current decreases from the pulse level to the base level, the molten material retracts toward the electrode 134 and a new droplet is formed on the end of the electrode. In the ejection spray transition mode, one droplet is transitioned per current pulse. As can be seen in FIGS. 5a-5c, the arc 132 covers a relatively small percentage (e.g., 50% or less) of the weld pool 202 surface. At high deposition rates (e.g., 16 lb / hr), conventional pulse welding may have a small and concentrated arc that undesirably agitates the weld pool 202, resulting in instability.

[0045] The present invention uses a pulsed welding waveform. During each current pulse, the molten metal is transferred to the workpiece by: an ejection-type spray of molten droplets, followed by an axial spray and / or a rotary spray of the molten metal. These two or three different spray transfer modes occur sequentially during a single current pulse, thereby producing a hybrid pulse welding process. Figures 6a to 6e show a hybrid pulse welding process, which uses an ejection-type spray transition (Figure 6a, Figure 6b), followed by a stream or axial spray transition (Figure 6c), and is followed by a rotary spray of the molten metal (Figure 6d). The hybrid transition combines at least two different metal transfer modes during one current pulse. The hybrid transition is accomplished by using a pulsed welding waveform, wherein the peak current level and the frequency and duration of the peak current portion of the waveform are sufficient to eject molten droplets from the end of the electrode toward the weld zone during the peak current portion and to cause the molten droplets to be followed by a stream spray and / or a rotary spray transition of the molten metal. For a given high metal deposition rate (e.g., 16 lb / hr to 25 lb / hr) and wire feed speed (e.g., 400 to 1000 inches / minute), the pulse waveform of the present invention has a slower frequency than a conventional pulsed gas metal arc welding (GMAW-P) waveform that transfers only one droplet per pulse. For example, in a deposition operation with a metal deposition rate of approximately 16 lb / hr, a conventional pulse welding waveform may have a frequency in the range of 200 Hz to 400 Hz, whereas the waveform used in the present hybrid pulse welding process is slower and may have a frequency in the range of 120 Hz to 150 Hz.

[0046] Compared to the conventional heavy manufacturing GMAW-P welding mode in which each pulse transitions one droplet to the weld zone, the hybrid pulse welding process shown in Figures 6a to 6e uses a slower pulse rate or frequency and longer pulses. Therefore, the arc 132 becomes less concentrated and wider, and it evens out the pressure applied to the weld pool 202, which improves stability and allows better control of the weld pool. That is, the arc 132 of the hybrid pulse welding process covers a larger portion of the surface of the molten weld pool 202 compared to the conventional pulse welding process. Both processes will apply similar forces to the weld pool 202 during welding, but these forces are dispersed over a larger area of ​​the weld pool in the hybrid pulse welding process. The lower pressure applied to the weld pool 202 combined with the slower pulse frequency causes the hybrid pulse welding process to stir the weld pool to a lesser extent than the conventional pulse welding process. This improves the stability of the welding process at high deposition rates. In addition, the slower the pulse frequency of the hybrid pulse welding process, the easier it is to affect the operator's senses, allowing the operator to slow down and accurately make larger welds.

[0047] After each current pulse of the hybrid pulse welding process and after the stream jet transition or the rotary jet transition following the ejection ejection of the molten droplet 200, the welding current is reduced to the base current level to stop the jet transition and allow another molten droplet to grow on the end of the electrode 134. The metal is transferred through at least two different jet modes during each current pulse; a large ejection droplet followed by a smaller axial ejection or rotary jet droplet. The jet transition is interrupted by the low current circulating base current portion that occurs immediately after each current pulse, which disrupts the rotation of the molten metal before it becomes uncontrolled and unstable.

[0048] Figures 6a and 6b show that the initial droplet is ejected into the weld zone by a current pulse that exceeds the jet transition transition current level. Figures 6c and 6d show an axial jet transition and a rotary jet transition during the same current pulse. The molten stream 204 has just begun to rotate in Figure 6d. The base current portion of the welding waveform interrupts the axial / rotary jet transition, as can be seen in Figure 6e. The base current level is below the jet transition transition current level and stops the transfer of molten metal while maintaining the arc 132. At higher deposition rates, some rotary jet transition may occur, which may cause instability and spatter. However, the rotary jet transition can be controlled by limiting the duration of the peak current portion of the welding waveform after the droplet 200 is ejected toward the weld zone.

[0049] The hybrid pulse welding process shown in Figures 6a-6e begins as a normal ejected droplet transfer, but continues to allow a stream of droplets to transfer via axial jet and / or rotary jet by slowing down the pulse frequency and allowing the arc to spread out over the surface of the weld pool to a greater extent than in conventional pulse welding. The hybrid pulse welding process combines droplet transfer of a GMAW-P type transfer mode (large droplet) with axial and / or rotary jet transfer modes using a single current pulse.

[0050] 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 area of ​​the arc covering the weld pool is almost the size of the weld pool), the arc applies uniform pressure to the weld pool. The hybrid pulse welding process shown in Figures 6a to 6e can enlarge the arc area to almost the size of the weld pool 202 to provide more uniform pressure on the weld pool compared to conventional GMAW-P operations. For example, during a hybrid pulse welding deposition operation, the 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. This can allow the operator to better control the weld pool. In conventional GMAW-P welding, the ratio of the surface area of ​​the weld pool to the area covered by the arc increases to above 1 (e.g., the arc is substantially smaller than the size of the weld pool), and as the deposition rate increases, the molten pool tends to become turbulent and will sway from side to side around the arc, resulting in instability and spatter. The larger arc cone 132 shown in Figures 6a-6e tends to agitate the weld pool 202 to a lesser extent than the narrower arc cones used in conventional heavy manufacturing GMAW-P welding.

[0051] Figure 7 An example hybrid pulse welding voltage waveform 300 and current waveform 302, and a conventional GMAW-P voltage waveform 304 and current waveform 306 are shown. As can be seen, the welding waveforms 300, 302 for the hybrid pulse welding process have a peak voltage and current portion 308, and a base voltage and current portion 310. The base portion 310 may include a tail-out from a peak current level to a preset base current level. The duration of the peak portion 308 and the base portion 310 in the hybrid pulse welding waveforms 300, 302 is much longer than that of the conventional pulse welding waveforms 304, 306. As described above, an example frequency range for the hybrid pulse welding waveform is 120 Hz to 150 Hz, although other frequencies below 120 Hz and above 150 Hz are possible, and the deposition rate of the hybrid pulse welding process can exceed 16 pounds per hour.

[0052] As can be seen, the hybrid pulse welding waveforms 300, 302 include a series of current pulses 308 and staggered base current portions 310, such that each current pulse is separated from the previous current pulse by the previous base current portion and from the subsequent current pulse by the subsequent base current portion. During each current pulse, before the subsequent base current portion occurs, a molten droplet is ejected from the tip of the wire electrode and is followed by a stream or axial jet of molten metal away from the tip of the wire electrode. The longer peak portion 308 of the hybrid pulse welding waveforms 300, 302 (compared to conventional pulse waveforms 304, 306) occurs during the current pulse with an axial jet transition followed by an ejective transition of molten droplets. During each current pulse, before the next base current portion occurs, molten metal is transferred from the wire electrode to the workpiece by an ejective jet transition mode and then by a subsequent second jet transition mode different from the ejective jet transition mode (e.g., a stream or axial jet transition mode or a rotating jet transition mode). During the current pulse, the rotary jet transition mode may be followed by the streaming or axial jet transition mode. Thus, during each current pulse, before the subsequent base current portion occurs, the ejected molten droplets may be followed by one or both of the streaming / axial jet and the rotary jet of the molten metal away from the tip of the wire electrode. In certain embodiments, during the current pulse and before the subsequent base current portion occurs, the streaming / axial jet of the molten metal is followed by the rotary jet of the molten metal. In such embodiments, three different transition modes occur during each current pulse (the ejected jet transition mode, followed by the streaming / axial jet transition mode, followed by the rotary jet transition mode). The subsequent or next base current portion following the current pulse stops the ejection transition mode (e.g., stops the streaming / axial jet mode or the rotary jet mode), and allows the droplets to accumulate and allows the wire electrode to be pushed into position in the next transition period. The transition from the base current portion 310 to the current peak 308 may be slower in the hybrid pulse welding waveform 300, 302 than in the conventional pulse welding waveform 304, 306. Droplet growth occurs during both the base portion 310 and the transition to the current peak 308. During the transition to the current peak 308, the current is not high enough to promote spray transfer, but the heating of the wire electrode is significantly higher than during the base portion 310. The end of the wire electrode will melt further during the transition to the current peak 308, and the size of the molten droplets will increase due to surface tension. Slowing the transition from the base current portion 310 to the current peak 308 will promote the growth of larger droplets, which is desirable. At the current levels used in the hybrid pulse welding process, the ejective spray transfer mode tends to be more stable than the streaming / axial or rotating spray transfer modes, and therefore, the larger droplet formation of the ejective spray transfer mode may be desirable.

[0053] As discussed above, the hybrid pulse waveform produces a larger arc area across the weld pool than the arc produced in a conventional GMAW-P operation. At high deposition rates (e.g., 16 lb / hr or greater), the larger arc coverage area is more gradual on the molten weld pool. Conventional GMAW-P pulse welding waveforms produce smaller, more concentrated arcs with short arc lengths at such high deposition rates. When conventional GMAW-P welding is performed at approximately above 16 lb / hr, the depression formed in the weld pool becomes too large and the weld pool begins to wrap the arc almost into a submerged arc, and the weld pool begins to become unstable as the liquid metal (weld pool) sways from one side to the other. The hybrid pulse welding process discussed above can reduce the agitation and instability of the molten weld pool by amplifying the arc, which applies a more uniform pressure across the weld pool. In addition, the slower the pulse frequency used in the hybrid pulse welding process, the easier it is to affect the operator's senses (e.g., vision and / or hearing), thereby allowing the operator to slow down and accurately make larger welds.

[0054] Figure 8 Another example hybrid pulse welding voltage waveform 312 and current waveform 314 for performing hybrid metal transfer are shown. A high peak current portion 316 has a peak current level greater than 600A. The high peak current portion 316 causes molten droplets to be ejected from the tip of the wire electrode toward a weld zone on the workpiece. A second lower peak current portion 318 (e.g., approximately 400A) follows the high peak current portion. The second peak current portion 318 provides a spray current level that is lower than the peak current level of portion 316. The second peak current portion 318 causes one or both of a stream spray and a rotational spray of molten metal toward the weld zone. A base current portion 320 having a current level less than 300A, for example, follows the second peak current portion 318. The base current portion 320 may include a tail from the spray current level of the second peak current portion 318 to a preset base current level. The base current portion 320 stops the spray transition from occurring during the second peak current portion 318 and allows droplets to accumulate and the wire electrode to be pushed into position during the next transition period.

[0055] Fig. 9An embodiment of an example controller 152 controller operatively connected to a power supply to control an output current waveform is shown. The controller 152 includes at least one processor 414, which can communicate with a number of peripheral devices via a bus subsystem 412. These peripheral devices may include a storage subsystem 424, which includes, for example, 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 allow a user to interact with the controller 152. The network interface subsystem 416 provides an interface to an external network and is connected to corresponding interface devices in other computer systems.

[0056] The user interface input device 422 may include a keyboard, a pointing device (such as a mouse, trackball, touch pad or graphics tablet), a scanner, a touch screen incorporated into a display, an audio input device (such as a voice recognition system, a microphone), and / or other types of input devices. In general, the term "input device" used is intended to include all possible types of devices and ways to input information into the controller 152 or onto a communication network.

[0057] 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 cathode ray tube (CRT), a flat panel device (such as a liquid crystal display (LCD)), a projection device, or some other mechanism for creating a visible image. The display subsystem may also provide a non-visual display such as via an audio output device. In general, the term "output device" used is intended to include devices and methods of all possible types of information output from the controller 152 to a user or to another machine or computer system.

[0058] The storage subsystem 424 provides a non-transitory computer-readable storage medium for storing programming and data structures that provide the functionality of some or all 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 828 used in the storage subsystem may include multiple memories, including: a main random access memory (RAM) 430, which is used to store instructions and data during program execution; and a read-only memory (ROM) 432, in which fixed instructions are stored. The file storage subsystem 426 can provide a persistent storage area for program and data files, and may include a hard drive, flash memory, a floppy disk drive and associated removable media, a CD-ROM drive, an optical drive, or a removable media box. Modules that implement the functionality of certain embodiments can be stored in the storage subsystem 424 through the file storage subsystem 426, or stored in other machines accessible to the processor (s) 414.

[0059] The bus subsystem 412 provides a mechanism for the various different components and subsystems of the controller 152 to communicate with each other as desired. Although the bus subsystem 412 is shown schematically as a single bus, alternative embodiments of the bus subsystem may use multiple busses.

[0060] Many other configurations of controller 152 (having Fig. 9 Controllers with more or fewer components than the depicted are possible.

[0061] It should be clear that the present disclosure is by way of example, and that various changes may be made by adding, modifying or removing details without departing from the reasonable scope of the teachings contained in the present disclosure. Therefore, the present invention is not limited to the specific details of the present disclosure, unless the appended claims are necessarily so limited.

Claims

1. An arc welding or additive manufacturing system comprising: Wire feeder; Welding torch; a welding wire electrode driven through the welding torch by the wire feeder; as well as an arc generation power supply operatively connected to the welding torch to deliver a pulse waveform to the wire electrode during a cladding operation, Wherein, the pulse waveform includes a series of current pulses and staggered base current portions, so that each current pulse is separated from a previous current pulse by a previous base current portion and is separated from a subsequent current pulse by a subsequent base current portion, and during each current pulse, the molten metal is transferred from the welding wire electrode to the workpiece through an ejection-type spray transition mode and a subsequent second spray transition mode different from the ejection-type spray transition mode, wherein, during the ejection-type spray transition mode, molten droplets are ejected from the end of the welding wire electrode toward the workpiece, and during the subsequent second spray transition mode, rotational spraying of the molten metal flow from the end of the welding wire electrode toward the workpiece occurs before the next base current portion.

2. The arc welding or additive manufacturing system of claim 1, 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 during which the rotating spray of molten metal occurs, wherein the spray current level is less than the peak current level.

3. The arc welding or additive manufacturing system of claim 1, wherein: The subsequent base current portion stops the rotating spray transfer of the molten metal.

4. The arc welding or additive manufacturing system of claim 1, wherein: The frequency of the pulse waveform is in the range of 120 Hz to 150 Hz, and the deposition rate of the deposition operation is greater than 16 pounds per hour.

5. The arc welding or additive manufacturing system of claim 4, wherein: The arc from the wire electrode covers at least 80% of the surface area of ​​the molten weld pool during the cladding operation.

6. An arc welding or additive manufacturing system comprising: Wire feeder; Welding torch; a welding wire electrode driven through the welding torch by the wire feeder; as well as an arc generation power supply operatively connected to the welding torch to deliver a pulse waveform to the wire electrode during a cladding operation, Wherein, the pulse waveform includes a series of current pulses and staggered base current portions, so that each current pulse is separated from the previous current pulse by the previous base current portion and separated from the subsequent current pulse by the subsequent base current portion, and during each current pulse, the molten metal is transferred from the welding wire electrode to the workpiece through an ejection-type spray transition mode and a subsequent second spray transition mode different from the ejection-type spray transition mode, wherein, during the ejection-type spray transition mode, molten droplets are ejected from the end of the welding wire electrode toward the workpiece, and during the subsequent second spray transition mode, axial and rotational spraying of the molten metal flow from the end of the welding wire electrode toward the workpiece occurs before the next base current portion.

7. The arc welding or additive manufacturing system of claim 6, wherein: The subsequent base current partially stops one of the axial ejection and the rotational ejection of molten metal.

8. The arc welding or additive manufacturing system of claim 7, 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 an ejection current level during which the axial ejection and the rotational ejection of molten metal occur, wherein the ejection current level is less than the peak current level.

9. The arc welding or additive manufacturing system of claim 6, wherein: The axial jet is followed by the rotary jet of molten metal before the subsequent base current portion occurs.

10. The arc welding or additive manufacturing system of claim 6, wherein: The frequency of the pulse waveform is in the range of 120 Hz to 150 Hz, and the deposition rate of the deposition operation is greater than 16 pounds per hour.

11. The arc welding or additive manufacturing system of claim 10, wherein: The arc from the wire electrode covers at least 80% of the surface area of ​​the molten weld pool during the cladding operation.

12. An arc welding or additive manufacturing system comprising: Wire feeder; Welding torch; a welding wire electrode driven through the welding torch by the wire feeder; as well as an arc generation power supply operatively connected to the welding torch to deliver a pulse waveform to the wire electrode during a cladding operation, Wherein, the pulse waveform includes a series of current pulses separated by corresponding base current portions, and during each current pulse in the series of current pulses, the molten metal is transferred from the welding wire electrode to the workpiece through an ejection-type spray transition mode and a subsequent second spray transition mode different from the ejection-type spray transition mode, wherein, during the ejection-type spray transition mode, molten droplets are ejected from the end of the welding wire electrode toward the workpiece, and during the subsequent second spray transition mode, the molten metal flow is ejected axially from the end of the welding wire electrode toward the workpiece before the next base current portion.

13. The arc welding or additive manufacturing system of claim 12, wherein: The next base current partially stops the axial ejection of molten metal.

14. The arc welding or additive manufacturing system of claim 13, 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 lower current level during which the axial ejection of molten metal occurs, wherein the lower current level is less than the peak current level.

15. The arc welding or additive manufacturing system of claim 12, wherein: The frequency of the pulse waveform is in the range of 120 Hz to 150 Hz, and the deposition rate of the deposition operation is greater than 16 pounds per hour.

16. The arc welding or additive manufacturing system of claim 15, wherein: The arc from the wire electrode covers at least 80% of the surface area of ​​the molten weld pool during the cladding operation.

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