System and method for welding

Abstract

A system and method for welding. In some embodiments, the method includes: performing, by an automated welder, a cycle of a weld to fill a gap, the cycle including: a first dwell; a first excursion forming a first excursion bead; a second dwell; and a second excursion, the automated welder forming, during the entire second excursion, a weld pool in contact with the first excursion bead.

Description

SYSTEM AND METHOD FOR WELDINGCROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] The present application claims priority to and the benefit of U.S. Provisional Application No. 63 / 606,007, filed December 4, 2023, entitled "SYSTEM AND METHOD FOR WELDING", the entire content of which is incorporated herein by reference.FIELD

[0002] One or more aspects of embodiments according to the present disclosure relate to systems and methods for joining metal, and more particularly to a system and method for welding.BACKGROUND

[0003] Welding may be employed to join pieces of metal, e.g., to join metal plates.

[0004] It is with respect to this general technical environment that aspects of the present disclosure are related.SUMMARY

[0005] According to an embodiment of the present disclosure, there is provided a method, including: performing, by an automated welder, a cycle of a weld to fill a gap, the cycle including: a first dwell; a first excursion forming a first excursion bead; a second dwell; and a second excursion, the automated welder forming, during the entire second excursion, a weld pool in contact with the first excursion bead.

[0006] In some embodiments, the automated welder is an automated gas metal arc welding (GMAW) welder.

[0007] In some embodiments, an excursion travel velocity during the first excursion and during the second excursion is constant.

[0008] In some embodiments, a dwell travel velocity of the first dwell and a dwell travel velocity of the second dwell are calculated based on a filler wire diameter, a width of the gap, and a desired weld pass thickness.

[0009] In some embodiments, the dwell travel velocity of the first dwell and the dwell travel velocity of the second dwell are calculated further based on a filler wire feed speed, and a dwell time.

[0010] In some embodiments: an oscillation speed during the first excursion and during the second excursion is a constant speed; and the dwell travel velocity of the first dwell and the dwell travel velocity of the second dwell are calculated further based on the constant speed.

[0011] In some embodiments, the method includes calculating a duration of the weld, based on the durations of a plurality of cycles, wherein: the cycle is a first cycle of the plurality of cycles, and a duration of a second cycle, performed after the first cycle, is calculated based on a total travel distance of the first cycle.

[0012] In some embodiments, the performing of the cycle includes: using automatic height control during the first excursion and the second excursion; and disabling automatic height control during the first dwell and the second dwell.

[0013] According to an embodiment of the present disclosure, there is provided a system, including: a welder, including: a filler wire feed unit for feeding filler wire; and a processing circuit configured to control a position of a distal end of the filler wire, the processing circuit being configured to perform a method, the method including: performing a cycle of a weld to fill a gap, the cycle including: a first dwell; a first excursion forming a first excursion bead; a second dwell; and a second excursion, the welder forming, during the entire second excursion, a weld pool in contact with the first excursion bead.

[0014] In some embodiments, the welder is an automated gas metal arc welding (GMAW) welder.

[0015] In some embodiments, an excursion travel velocity during the first excursion and during the second excursion is constant.

[0016] In some embodiments, a dwell travel velocity of the first dwell and a dwell travel velocity of the second dwell are calculated based on a filler wire diameter, a width of the gap, and a desired weld pass thickness.

[0017] In some embodiments, the dwell travel velocity of the first dwell and the dwell travel velocity of the second dwell are calculated further based on a filler wire feed speed, and a dwell time.

[0018] In some embodiments: an oscillation speed during the first excursion and during the second excursion is a constant speed; and the dwell travel velocity of the first dwell and the dwell travel velocity of the second dwell are calculated further based on the constant speed.

[0019] In some embodiments: the method includes calculating a duration of the weld, based on the durations of a plurality of cycles; the cycle is a first cycle of the plurality of cycles; and a duration of a second cycle, performed after the first cycle, is calculated based on a total travel distance of the first cycle.

[0020] In some embodiments, the performing of the cycle includes: using automatic height control during the first excursion and the second excursion; and disabling automatic height control during the first dwell and the second dwell.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] These and other features and advantages of the present disclosure will be appreciated and understood with reference to the specification, claims, and appended drawings wherein:

[0022] FIG. 1 A is a front view of two plates separated by a tapered gap, according to an embodiment of the present disclosure;

[0023] FIG. 1 B is a cross-sectional view of the two plates of FIG. 1A, and of a partially formed weld, according to an embodiment of the present disclosure;

[0024] FIG. 2A is a front view of two metal plates separated by a tapered gap, and joined by a short section of weld at the bottom of the gap, according to an embodiment of the present disclosure;

[0025] FIG. 2B is a photograph of a portion of a partially completed weld joining two metal plates, according to an embodiment of the present disclosure;

[0026] FIG. 2C is a photograph of a portion of a completed weld joining two metal plates, according to an embodiment of the present disclosure; and

[0027] FIG. 3 is a schematic drawing of a system for welding, according to an embodiment of the present disclosure.DETAILED DESCRIPTION

[0028] The detailed description set forth below in connection with the appended drawings is intended as a description of exemplary embodiments of a system and method for welding provided in accordance with the present disclosure and is not intended to represent the only forms in which the present disclosure may be constructed or utilized. The description sets forth the features of the present disclosure in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the scope of the disclosure. As denoted elsewhere herein, like element numbers are intended to indicate like elements or features.

[0029] When fabricating metal parts or structures, metal plates may be welded together using various arc welding processes, in various orientations. Welding processes may include a gas tungsten arc welding (GTAW) (or tungsten inert gas (TIG)) process, in which the arc may be formed between a tungsten electrode and the weld pool; or a gas metal arc welding (GMAW) process, in which the arc may be formed between the filler wire and the weld pool. Welding may be performed by an automated welder including a weld head that moves relative to a gap between plates being joined (as a result of motion of the weld head or motion of the plates, or both). Such an automated welder may be controlled by a processing circuit, which may be configured to perform some or all of the calculations disclosed herein, and which may control accordingly the motion of the weld head relative to the gap between plates being joined. As used herein, an “automated welder” is a welder in which the motion of the weld head relative to the part or parts being welded is electronically controlled (e.g., using computer-controlled actuators). For example, each of a robotic welder, a carriage welder, and a mechanized welder is an automated welder as the term “automated welder” is used herein. Further, an “automated welder” may be capable of completing a portion of a weld (e.g., a weld cycle, a half weld cycle, a portion of a weld pass, or aportion of a weld (e.g., a portion including one or more full weld passes)) without realtime operator input (e.g., without operator input being received while the weld is performed).

[0030] FIGs. 1A and 1 B show two plates 105 being joined by welding. The weld illustrated is a vertical-up weld, with the up (vertical) direction being parallel to the Z axis shown. The welding process may include a plurality of cycles, each cycle including two excursions 120 and two dwells 125 (discussed in further detail below). During each excursion 120 a bead (referred to herein as an excursion bead) is deposited, with each excursion bead extending substantially in the X direction, from one plate to the other, across the gap 110 between the plates. At the end of each excursion, the weld head (and, e.g., the arc and the distal end of the filler wire) may dwell, during some time interval (which may be referred to as the “dwell”), at the edge of the plate at which the excursion ended, with the weld pool in contact with the edge of the plate during the dwell. As used herein, the distal end of the filler wire is the end that is in contact with the arc.

[0031] In FIGs. 1 A and 1 B, each of the plates is parallel to the X-Z plane, where the X direction is horizontal. When performing a vertical-up weld, control of the weld pool may be challenging when the gap between the plates is large compared to the size of the weld pool, because the weld pool may not remain centered over the previously formed excursion bead and may instead be offset from the previously formed bead in the +Y or -Y direction. As such, a ceramic backing 115 may be secured behind the two plates, as illustrated in FIG. 1 B, and each excursion bead of the weld may be held in place while solidifying by (i) the excursion bead below it and (ii) the ceramic backing. FIG. 1A shows a partially completed excursion 130 and FIG 1 B shows the resulting partially formed excursion bead 135. Each of the plates 105 may be beveled along the edge that bounds the gap, as shown in FIG. 1 B (for ease of illustration the bevels are not shown in FIG. 1A).

[0032] During the weld, the weld pool may move, as a result of motion of the weld head, or of the plates, or both, in the Z direction (which may be referred to as the “travel” direction) and in the X direction (which may be referred to as the “excursion” direction). During the dwell, the weld pool may move in the travel direction with a velocity referred to as the dwell travel velocity. During each excursion, the weld pool may move in theexcursion direction with a speed referred to as the oscillation speed, and the weld pool may move in the travel direction with a velocity referred to as the excursion travel velocity.

[0033] The weld may be performed using, e.g., gas metal arc welding with metal- cored filler wire. The shield gas nozzle used in such a process may be sized and positioned (and the contact tip to work distance may be selected) to avoid collisions between the nozzle and the plates 105. During any excursion of the root pass, if a loss of contact between the weld pool and the previously formed excursion bead occurs, the arc may become extinguished, which may result in lost time (e.g., while an operator intervenes to reset the automated welder) and a degradation of weld quality. As such, the distance traveled during each dwell, and the excursion travel velocity, may be selected such that each excursion bead overlaps the previously formed excursion bead and such that contact between the weld pool and the previously formed excursion bead is maintained during each excursion.

[0034] The volume Vcof metal deposited during a cycle may be calculated as

[0035] Vc= nd2Vftc / 4, (1 )

[0036] where d is the diameter of the filler wire, vfis the filler wire feed speed, and tcis the cycle time.

[0037] The cycle time may be given by

[0038] tc= 2td+ 2Wc / vo, (2)

[0039] where tdis the dwell time, and 2Wc / vois the total time for the two excursions of the cycle, with v0being the oscillation speed and Wcbeing the width of the gap midway between the two excursions. As such, the volume Vcof metal deposited during a cycle may be calculated by substituting the value of tcfrom Equation 2 into Equation 1 , and the volume Vcmay be a function of Wc, which may vary along the length (in the Z direction) of the gap.

[0040] The total travel Dcfor the cycle may then be calculated based on the desired layer thickness T for the weld layer (where the layer thickness T is the thickness in the Y direction), from the following equation (which is based on the observation that the volume Vcof metal deposited during the cycle is the volume of a rectangular parallelepipedhaving dimensions equal to (i) the thickness T of the weld layer, (ii) the width Wc, and (iii) the total travel Dcfor the cycle):

[0041] WCDCT = Vc.

[0042] As such, the total travel Dcfor any cycle may be calculated from (i) the volume Vcof metal deposited during the cycle, (ii) the thickness T of the weld layer, and (iii) the width Wc.

[0043] Dc= VC / (WCT) (3)

[0044] In some embodiments, a “bricklayer” weld path is used, in which the excursion travel velocity is zero. In such an embodiment, all of the travel Dcfor the cycle occurs during the dwell, and the dwell travel velocity vtmay be calculated as

[0045] vt= Dc / 2td).

[0046] The method disclosed herein may make it possible to calculate the entire weld path using a small number of input parameters, including, e.g., the width at the bottom of the gap, the width at the top of the gap, the filler wire feed speed and diameter, and the layer thickness. For example, for a filler wire feed speed vfof 120 inches per minute, a filler wire diameter d of 0.035 inches, a weld layer thickness T of 0.22 inches, a gap width Wcof 0.31 inches, an oscillation speed v0of 15.5 inches per minute, and a dwell time tdof 1 second, a suitable dwell travel velocity may be 3.7 inches per minute (with tc= 4.4 s, Vc= 0.00847 cubic inches, and Dc= 0.124 inches).

[0047] To plan a path for an entire weld (which may include a plurality of cycles), an iterative approach may be used. For example, the total travel Dcfor the first cycle (at the bottom end of the weld) may be calculated (based on the width of the gap 110 at the bottom). The total travel Dcfor the first cycle may then be used to calculate (i) the location, along the length (in the Z direction) of the gap 110, of the second cycle, (ii) the width Wcof the gap 110 at the second cycle, and (iii) the total travel Dcfor the second cycle. The width of the gap at the position of any cycle may (if the gap has straight edges, as illustrated for example in FIG. 1A) be equal to Wo+ (14^ - W^z / L, where Wois the width of the gap at one end of the gap (the end at which the weld pass starts), 1 ^ is the width of the gap at the other end of the gap (the end at which the weld pass ends), z is the position of the cycle along the gap, and L is the length of the gap. In someembodiments, (e.g., if the gap does not have straight edges) the width of the gap is calculated based on a plurality of measurements of the width of the gap, made along the length of the gap (e.g., measurements made before the weld is started, or measurements made (e.g., using through-the-arc seam tracking, discussed in further detail below) while the weld is being performed), and the width of the gap at the position of any cycle may then be calculated (e.g., using a spline (e.g. a piecewise linear spline or a piecewise cubic spline)) based on the measured widths. The total travel for the first cycle and the total travel for the second cycle may then be used in a similar manner to calculate the location of the third cycle, the width of the gap 110 at the third cycle, and the total travel for the third cycle. This process may be repeated to extend the calculated weld path until a cycle is found that has a location sufficiently close to the top end of the gap 110 to complete the weld pass (e.g., the root pass). If sufficient space remains, an additional half-cycle (e.g., an additional excursion 120) may be added to the path, after the final cycle. The duration of the entire weld may then be calculated as the sum of the cycle times tdof all of the cycles of the weld (plus the duration of any partial cycle (e.g., of any half-cycle)).

[0048] To perform the weld, the automated welder may be controlled according to the equations above, or it may instead be controlled to follow other (e.g., similar) welding parameters. For example, the welder may be programmed to use a dwell travel velocity that varies linearly with distance traveled along the weld (over a time interval equal to the duration of the weld), between the dwell travel velocity calculated for the first cycle and the dwell travel velocity calculated for the last cycle. Similarly, the welder may be programmed to use a width that varies linearly with distance traveled along the weld. As another example, the total travel per cycle (and, e.g., the dwell travel velocity) may be within X% of the calculated value, where X is a number less than 40%. As another example, the total travel within each cycle may be within 50% of a total travel for the cycle that would result in the layer thickness for the cycle being equal to the average layer thickness for the weld.

[0049] In some embodiments, through-the-arc seam tracking is used to cause the automated welder to follow the gap, so that each excursion is substantially centered (in the X-direction) in the gap. This may be accomplished by monitoring and comparing thewelding current during (or at the beginning of) each of the two dwells at the ends of an excursion. During a dwell, the welding current may increase relative to the current during an excursion because (i) the power supply may maintain a constant voltage between the contact tip and the substrate (e.g., either of the plates) and (ii) during a dwell, the length of the portion of filler wire between the contact tip and the weld pool (which may be referred to as the filler wire extension distance) may decrease as the weld pool climbs the beveled edge of the plate toward the contact tip. This reduction in length may result in an increase in weld current, the increase being greater when the weld pool climbs a greater distance up the bevel. As such, if the dwell current is greater at a first end of the excursion than at a second end of the excursion, it may imply that the excursion is not centered within the gap, and that it is offset so that the second end is nearer the center of the gap than the first end. The control software may then adjust the position of the next excursion so that it is better centered. The automatic height control system of the automated welder (discussed in further detail below), if used, may be disabled during each dwell. A similar system may be used to automatically adjust to variations in gap width; for example, (i) if the average current of the two dwells at the end of an excursion is greater than a target value, the length of the next excursion may be reduced, from its planned length, and (ii) if the average current of the two dwells at the end of an excursion is less than the target value, the length of the next excursion may be increased, from its planned length. In some embodiments the value of Wcis set to be slightly larger than the width of the gap (e.g., 0.050 inches larger) so that each excursion is sufficiently long to allow the weld pool to climb up the bevel to some extent at the end of each excursion (and to begin each excursion with the weld pool part-way up the bevel).

[0050] Automatic height control may be performed by the control software of the automated welder as follows. Because the welding current may depend on the contact tip to work distance, if the weld current exceeds a certain setpoint current, it may be an indication that the contact tip to work distance is too small, and if the weld current is less than the setpoint current, it may be an indication that the contact tip to work distance is too great. The control software of the automated welder may therefore move the weld head (in the Y direction) (i) closer to the weld when the current is less than the threshold and (ii) farther from the weld when the current is greater than the threshold. The effectof this control may be to cause both the welding current and the contact tip to work distance to remain at or near their respective desired values. Automatic height control may also be used to compensate for weld pass thickness variations. For example, if, while automatic height control is active, the weld head is closer to the plates 105 during a second part of a pass than during a first part of the pass, the control software of the automated welder may infer that the total thickness of the previously deposited weld passes is less in the second part of the pass than in the first part of the pass, and the software may cause the layer thickness of the current pass to be accordingly greater (e.g., by increasing the wire feed speed or decreasing the average travel speed) during the second part of the pass.

[0051] Through-the-arc seam tracking and automatic height control may be used to allow the automated welder to adapt to various gap centerline orientations (which, like the gap shown in FIG. 2A, and unlike the gap shown in FIG. 1A, may not be exactly vertical), and to plates that are not perfectly flat (e.g., as a result of warping that may occur as the weld proceeds). This may significantly reduce the need for operator supervision and assistance during a weld.

[0052] FIGs. 2A - 2C show the results of a reduction to practice, in which two 3 / 8” thick plates, separated by a gap having a width of 0.240 inches at the bottom and a width of 0.860 inches at the top, were joined by a weld according to a method disclosed herein.

[0053] Using the equations above to calculate the travel distance per dwell may result in a dwell time that varies as the weld pass progresses; for example, if the gap 110 is wider at the upper end than at the lower end (as illustrated in FIG. 1 A), the travel distance per dwell may decrease as the weld progresses. In some embodiments, one or more other parameters may be adjusted (in addition to, or instead of, the dwell travel velocity) as the weld progresses, to maintain constant layer thickness. For example, as the weld progresses (for a gap that is wider at the top than at the bottom (as illustrated in FIG. 1 A)), the filler wire feed speed may increase, the dwell time may decrease, or the oscillation speed may decrease.

[0054] In some embodiments, the travel is non-zero during each excursion, but sufficiently small to avoid, during each excursion, a loss of contact between the weld pool and the previously formed excursion bead. Once the root pass of the weld has beendeposited, subsequent passes may be formed using the same equations and weld path shape (e.g., a bricklayer weld path), or a different path (e.g., one that does not ensure contact between the weld pool and the excursion bead) may be employed.

[0055] In some embodiments the ceramic backing 115 is slightly curved (e.g., concave), so that the root pass of the weld is also slightly curved. The effect of this curvature may be ignored in the calculations above or it may be taken into account by using, for Wc, the distance across the gap along the curved surface of the ceramic backing 115. In some embodiments, parts or components other than plates (e.g., tubes or pipes) may be joined using an analogous process to that described herein for plates. Some of the methods described above calculate one or more parameters (e.g., the dwell travel velocity) for each cycle of the weld. In some embodiments, such calculations are instead performed for each half-cycle of the weld (each half-cycle including a dwell and an excursion). In some embodiments, as discussed above, the dwell travel velocity may be adjusted for every cycle (or, in some embodiments, for every half-cycle) so that an appropriate volume of metal is deposited during the cycle (or during the half-cycle). In some embodiments, other parameters may be adjusted, for every cycle or for every halfcycle, to accomplish the same objective (e.g., to cause an appropriate volume of metal to be deposited during the cycle or during the half-cycle). For example, any one of, or any combination of, the following parameters may be adjusted (in addition to, or instead of, the dwell travel velocity) to accomplish this objective: the dwell time, the filler wire feed speed, the oscillation speed, and the excursion travel velocity. In each case the parameter or parameters being adjusted may be selected such that the volume of filler wire fed during a cycle or a half-cycle is equal to (or approximately equal to, e.g., within 50% of) the volume of a parallelepiped having dimensions equal to (i) the desired thickness T of the weld layer, (ii) the width Wc, and (iii) the total travel (e.g., Dc) for the cycle or for the half-cycle. In embodiments in which the excursion travel velocity is nonzero, the excursion travel velocity may be selected to be sufficiently small for the weld pool to remain in contact, during the entire excursion, with the previously formed excursion bead.

[0056] FIG. 3 shows a welding system that may implement weld control based on the equations above. In some embodiments, such a welding system includes a welding head310 which includes a filler wire feed unit 312 for supplying the filler wire 314 to the weld (e.g., to the weld pool). The system for heating the weld pool is not explicitly shown; it may be, for example, an arc, with current flowing through the filler wire 314 (as discussed above), or, in other embodiments, through a separate (e.g., tungsten) electrode, or a laser. The system may further include one or more travel and excursion actuators 315 for controlling the motion of the welding head 310. The welding system may also include a control circuit 325, including (i) a travel and excursion actuator drive circuit 330, for interfacing to the travel and excursion actuators 315, (ii) a wire feed drive circuit 335, for controlling the feed speed of the filler wire 314, and (iii) a processing circuit 345 (described in further detail below) for performing high-level sensing or control functions such as sensing the welding current or commanding the travel and excursion actuators 315. The system may also include other elements (not shown) such as a welding power supply and controller, and one or more user interface devices such as a display, a keyboard, or a mouse.

[0057] As used herein, “a portion of” something means “at least some of’ the thing, and as such may mean less than all of, or all of, the thing. As such, “a portion of” a thing includes the entire thing as a special case, i.e., the entire thing is an example of a portion of the thing. As used herein, when a second quantity is “within Y” of a first quantity X, it means that the second quantity is at least X-Y and the second quantity is at most X+Y. As used herein, when a second number is “within Y%” of a first number, it means that the second number is at least (1 -Y / 100) times the first number and the second number is at most (1 +Y / 100) times the first number. As used herein, the word “or” is inclusive, so that, for example, “A or B” means any one of (i) A, (ii) B, and (iii) A and B.

[0058] Each of the terms “processing circuit” and “means for processing” is used herein to mean any combination of hardware, firmware, and software, employed to process data or digital signals. Processing circuit hardware may include, for example, application specific integrated circuits (ASICs), general purpose or special purpose central processing units (CPUs), digital signal processors (DSPs), graphics processing units (GPUs), and programmable logic devices such as field programmable gate arrays (FPGAs). In a processing circuit, as used herein, each function is performed either by hardware configured, i.e., hard-wired, to perform that function, or by more general-purpose hardware, such as a CPU, configured to execute instructions stored in a non- transitory storage medium. A processing circuit may be fabricated on a single printed circuit board (PCB) or distributed over several interconnected PCBs. A processing circuit may contain other processing circuits; for example, a processing circuit may include two processing circuits, an FPGA and a CPU, interconnected on a PCB.

[0059] As used herein, when a method (e.g., an adjustment) or a first quantity (e.g., a first variable) is referred to as being “based on” a second quantity (e.g., a second variable) it means that the second quantity is an input to the method or influences the first quantity, e.g., the second quantity may be an input (e.g., the only input, or one of several inputs) to a function that calculates the first quantity, or the first quantity may be equal to the second quantity, or the first quantity may be the same as (e.g., stored at the same location or locations in memory as) the second quantity.

[0060] It will be understood that, although the terms “first”, “second”, “third”, etc., may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed herein could be termed a second element, component, region, layer or section, without departing from the spirit and scope of the inventive concept.

[0061] Spatially relative terms, such as “beneath”, “below”, “lower”, “under”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that such spatially relative terms are intended to encompass different orientations of the device in use or in operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” or “under” other elements or features would then be oriented “above” the other elements or features. Thus, the example terms “below” and “under” can encompass both an orientation of above and below. The device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should be interpreted accordingly. The terminology usedherein is for the purpose of describing particular embodiments only and is not intended to be limiting of the inventive concept. As used herein, the terms “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art.

[0062] It will be understood that when an element or layer is referred to as being “on”, “connected to”, “coupled to”, or “adjacent to” another element or layer, it may be directly on, connected to, coupled to, or adjacent to the other element or layer, or one or more intervening elements or layers may be present. In contrast, when an element or layer is referred to as being “directly on”, “directly connected to”, “directly coupled to”, or “immediately adjacent to” another element or layer, there are no intervening elements or layers present.

[0063] Any numerical range recited herein is intended to include all sub-ranges of the same numerical precision subsumed within the recited range. For example, a range of "1.0 to 10.0" or “between 1.0 and 10.0” is intended to include all subranges between (and including) the recited minimum value of 1 .0 and the recited maximum value of 10.0, that is, having a minimum value equal to or greater than 1 .0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Similarly, a range described as “within 35% of 10” is intended to include all subranges between (and including) the recited minimum value of 6.5 (i.e. , (1 - 35 / 100) times 10) and the recited maximum value of 13.5 (i.e., (1 + 35 / 100) times 10), that is, having a minimum value equal to or greater than 6.5 and a maximum value equal to or less than 13.5, such as, for example, 7.4 to 10.6. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein.

[0064] Although exemplary embodiments of a system and method for welding have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. Accordingly, it is to be understood that a system and method for welding constructed according to principles of this disclosure may be embodied other than as specifically described herein. The invention is also defined in the following claims, and equivalents thereof.

Claims

WHAT IS CLAIMED IS:1 . A method, comprising: performing, by an automated welder, a cycle of a weld to fill a gap, the cycle comprising: a first dwell; a first excursion forming a first excursion bead; a second dwell; and a second excursion, the automated welder forming, during the entire second excursion, a weld pool in contact with the first excursion bead.

2. The method of claim 1 , wherein the automated welder is an automated gas metal arc welding (GMAW) welder.

3. The method of claim 1 , wherein an excursion travel velocity during the first excursion and during the second excursion is constant.

4. The method of claim 1 , wherein a dwell travel velocity of the first dwell and a dwell travel velocity of the second dwell are calculated based on a filler wire diameter, a width of the gap, and a desired weld pass thickness.

5. The method of claim 4, wherein the dwell travel velocity of the first dwell and the dwell travel velocity of the second dwell are calculated further based on a filler wire feed speed, and a dwell time.

6. The method of claim 5, wherein: an oscillation speed during the first excursion and during the second excursion is a constant speed; and the dwell travel velocity of the first dwell and the dwell travel velocity of the second dwell are calculated further based on the constant speed.

7. The method of claim 4, comprising calculating a duration of the weld, based on the durations of a plurality of cycles, wherein: the cycle is a first cycle of the plurality of cycles, and a duration of a second cycle, performed after the first cycle, is calculated based on a total travel distance of the first cycle.

8. The method of claim 1 , wherein the performing of the cycle comprises: using automatic height control during the first excursion and the second excursion; and disabling automatic height control during the first dwell and the second dwell.

9. A system, comprising: a welder, comprising: a filler wire feed unit for feeding filler wire; and a processing circuit configured to control a position of a distal end of the filler wire, the processing circuit being configured to perform a method, the method comprising: performing a cycle of a weld to fill a gap, the cycle comprising: a first dwell; a first excursion forming a first excursion bead; a second dwell; and a second excursion, the welder forming, during the entire second excursion, a weld pool in contact with the first excursion bead.

10. The system of claim 9, wherein the welder is an automated gas metal arc welding (GMAW) welder.11 . The system of claim 9, wherein an excursion travel velocity during the first excursion and during the second excursion is constant.

12. The system of claim 9, wherein a dwell travel velocity of the first dwell and a dwell travel velocity of the second dwell are calculated based on a filler wire diameter, a width of the gap, and a desired weld pass thickness.

13. The system of claim 12, wherein the dwell travel velocity of the first dwell and the dwell travel velocity of the second dwell are calculated further based on a filler wire feed speed, and a dwell time.

14. The system of claim 13, wherein: an oscillation speed during the first excursion and during the second excursion is a constant speed; and the dwell travel velocity of the first dwell and the dwell travel velocity of the second dwell are calculated further based on the constant speed.

15. The system of claim 12, wherein: the method comprises calculating a duration of the weld, based on the durations of a plurality of cycles; the cycle is a first cycle of the plurality of cycles; and a duration of a second cycle, performed after the first cycle, is calculated based on a total travel distance of the first cycle.

16. The system of claim 9, wherein the performing of the cycle comprises: using automatic height control during the first excursion and the second excursion; and disabling automatic height control during the first dwell and the second dwell.

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