Abstract:
A welding system or an enterprise using welding systems can communicate with cloud-based resources for the provision of services and products to facilitate the welding operations. The communications may be via wired or wireless media, and may be direct, or through other components, such as enterprise networks, peripheral devices, and so forth. The cloud-based resources may provide for storage of data, particularly welding data, processing of data, welding protocols, specifications and processes, financial transactions for the purchase, licensing or use of welding-related products and services, welding training, and so forth.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Non-Provisional of U.S. Provisional Patent Application No. 61/468,860, entitled “Method for Determining Arc Consistency and Electrode Extension During GMAW-P”, filed Mar. 29, 2011, which is herein incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    The present invention relates generally to the field of welding systems, and particularly to pulsed gas metal arc welding systems (GMAW-P), also known as pulsed metal inert gas (pulsed MIG) welding systems. 
         [0003]    Arc welding systems generally comprise a power supply that applies electrical current to an electrode so as to pass an arc between the electrode and a work piece, thereby heating the electrode and work piece to create a weld. In many systems, such as gas metal arc welding systems (GMAW), the electrode consists of a wire which is advanced through a welding torch. As the electrode is heated by the arc, the electrode melts and is joined to molten metal of the work piece to form the weld. By controlling the supply of voltage and current to the electrode, a GMAW system may control the manner in which the electrode is melted and deposited by the arc. For example, the voltage supply to the electrode may be held constant, while the current supply is varied so as to maintain a constant arc length independent of the distance between the contact tip and the work piece. A GMAW system may also supply voltage and current to an electrode in a periodic or pulsed manner, known as pulsed gas metal arc welding (GMAW-P) or pulsed metal inert gas (pulsed MIG) welding. 
         [0004]    In a GMAW system, the arc melts the end of the electrode into a molten ball and transfers the molten ball onto the work piece. Rather than provide a single constant voltage-controlled or constant current-controlled arc, GMAW-P welding systems supply voltage and current to the electrode according to a periodic pattern as a power pulse. For example, a GMAW-P welding system may supply a constant low voltage in a first phase (the background phase), and then supply a constant high voltage in a second phase (the peak phase). In such a way, an arc may provide only enough power to melt the electrode in the background phase, while providing sufficient power to transfer the molten electrode material to the work piece in the peak phase. A GMAW-P system may allow a variety of parameters to be programmed to affect the power applied to form the weld, such as constant voltage levels, fixed current beginning points, constant current ramp rates, minimum and maximum current limits, time allowed for each phase, and so forth. Thus, pulses and the applied power may not be identical, varying the consistency of the GMAW-P welding arc and weld quality. The GMAW-P welding arc may be affected by the components of the GMAW-P system, the power source, environmental conditions at the work piece or welding torch, and operator skill. These factors, among others, may affect the quality of a weld. 
       BRIEF DESCRIPTION 
       [0005]    In one embodiment, a welding system includes a welding torch, a base unit, and control circuitry. The base unit is configured to supply the welding torch with a pulsed electrical current for producing a welding arc in the welding torch. The control circuitry is configured to detect signals relating to the pulsed electrical current and to store in memory a pulsed waveform based on the signals as an idealized pulsed waveform. 
         [0006]    In another embodiment, a method includes detecting signals and storing in memory a pulsed waveform based on the signals. The signals relate to a pulsed electrical current supplied to a welding torch for producing a welding arc in the welding torch. The pulsed waveform is stored in memory as an idealized pulsed waveform based on the signals. 
         [0007]    In another embodiment, a welding system includes a welding torch, a base unit, and control circuitry. The base unit is configured to supply the welding torch with pulsed electrical signals for producing welding arcs in the welding torch. The control circuitry is configured to detect a first set of signals, store in memory a first pulsed power waveform, detect a second set of signals, compare a second pulsed power waveform with the first pulsed power waveform, and quantify a difference between the first pulsed power waveform and the second pulsed power waveform. The first set of signals relate to a first pulsed electrical current supplied to the welding torch by the base unit and the second set of signals relate to a second pulsed electrical current supplied to the welding torch by the base unit. The first pulsed power waveform is based on the first set of signals and the second pulsed power waveform is based on the second set of signals. 
     
    
     
       DRAWINGS 
         [0008]    These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
           [0009]      FIG. 1  is a block diagram of a welding system having control circuitry to analyze pulsed waveforms, in accordance with aspects of the present disclosure; 
           [0010]      FIG. 2  is a flow chart of a method for comparing a stored reference pulsed waveform to a sampled pulsed waveform, in accordance with aspects of the present disclosure; 
           [0011]      FIG. 3  is a chart of an ideal power pulse and the relative absolute value difference in power between sampled pulses and the ideal power pulse, in accordance with aspects of the present disclosure; and 
           [0012]      FIG. 4  is a chart of the average absolute valve power difference between sampled pulses and ideal power pulses with different electrode extensions, in accordance with aspects of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
         [0014]    The welding system and methods of the present invention may determine the consistency of a pulsed gas metal arc welding (GMAW-P) welding arc and weld parameters. The weld parameters may include, but are not limited to, electrode extension, shielding gas fluctuations, environmental conditions on a work piece, and melt-freeze of the electrode and work piece. A base unit of the welding system may be configured to supply a pulsed electrical current to a welding torch. The pulsed electrical current may relate to one or more pulsed waveforms, such as a voltage waveform, a current waveform, or a power waveform. Some pulsed waveforms (e.g., sampled pulsed waveforms) may be based at least in part on detected signals relating to the pulsed electrical current supplied to the welding torch. For example, a pulsed power waveform may represent a measured amplitude of the pulsed power waveform at discrete times during a pulse period. A memory of the welding system may store a plurality of pulsed waveforms for reference, comparison, and analysis. Some stored pulsed waveforms may be preset in memory, correspond to a simulated pulsed electrical current, and/or be loaded from a peripheral device (e.g., another welding system) or a connected network. 
         [0015]    Some pulsed waveforms may be stored as reference (e.g., ideal) pulsed waveforms. Ideal pulsed waveforms may be used for comparison with sampled pulsed waveforms. An operator may select (via an operator interface) the sampled pulsed waveform to be stored as an ideal pulsed waveform. For example, after performing a series of welds, the operator may select the sampled pulsed waveform corresponding to a desired quality weld to be the ideal pulsed waveform to be used for comparison to subsequent performed welds. After obtaining the ideal pulsed waveform, the welding system may compare sampled pulsed waveforms corresponding to subsequent welds to the ideal pulsed waveform. Comparison may yield differences between the ideal pulsed waveform and the sampled pulsed waveform. These differences may indicate inconsistencies in the GMAW-P welding arc relating to the sampled pulsed waveforms and the relative quality of the weld produced by the sampled pulsed waveform. For example, the sampled pulsed waveform from a relatively poor quality weld may yield differences when compared to the idealized pulsed waveform of a good quality weld. Small differences may indicate a relatively consistent arc. Comparison may also readily indicate other parameters, such as electrode extension, that may otherwise be difficult to determine, particularly in real-time. These differences and parameters may be processed and/or displayed on an operator interface of the welding system. For example, the operator interface may present an alert to the operator if the difference exceeds a pulsed waveform difference threshold. The operator may adjust this pulsed waveform difference threshold. 
         [0016]    Turning now to the drawings,  FIG. 1  is a block diagram of a welding system  10  for determining consistency of a GMAW-P welding arc and weld parameters. In the illustrated embodiment, the welding system  10  is a GMAW-P welding system, although the present techniques may be used on other welding systems, such as other metal inert gas (MIG) welding systems, and so forth. The welding system  10  includes a base unit  12  operably coupled with a welding torch  14 . Placement of the welding torch  14  proximate to a work piece  15  allows an electrical current, supplied by a power supply  16 , to form an arc  18  from an electrode  20  (e.g., welding wire) to the work piece  15 . The arc  18  completes an electrical circuit from the power supply  16  to the electrode  20 , to the work piece  15 , then back to ground via a ground clamp  22  and a ground cable  24 . The ground cable  24  is operably coupled to the power supply  16  through control circuitry  26 . The heat produced by the arc  18  causes the electrode  20  and/or work piece  15  to transition to a molten state, facilitating the weld. 
         [0017]    The base unit  12  powers, controls, and supplies consumables to the welding torch  14  for a welding application. For example, the power supply  16  supplies the welding torch  14  with power (e.g., pulsed power waveforms), the wire feeder  28  supplies the electrode  20  from an electrode supply  30  (e.g., spool), and the gas supply  32  supplies shielding gas through a conduit  34 . The electrode  20  may be of various types, including traditional wire electrode or gasless wire electrode. Shielding gas from the gas supply  32  shields the weld area of the electrode  20  and work piece  15  from contaminants during welding, to enhance arc performance, and to improve the resulting weld. 
         [0018]    To precisely control the deposition of molten material from the electrode  20  onto the work piece  15 , the control circuitry  26  may control the power supply  16 , the wire feeder  28 , and the gas supply  32 . The control circuitry  26  may control the power supplied to the welding torch  14  by adjusting the voltage and current waveforms supplied to the welding torch  14 . In an embodiment, the control circuitry  26  may control the power supply  16  to supply power to the welding torch  14  at a desired power level through a series of power pulses. The power supply  16  may provide the desired power level to the welding torch  14  by varying the current and voltage supplied to the torch  14 . The control circuitry  26  monitors the supply voltage and current with a voltage sensor  36  and a current sensor  38 . By varying the voltage and current supplied to the welding torch  14 , the control circuitry  26  controls the intensity of the arc  18  and, accordingly, the manner in which the molten material from the electrode  20  is deposited onto the work piece  15 . In an embodiment, the control circuitry  26  may vary the power supplied to the welding torch  14  by voltage and current supplied by the power supply  16  to the welding torch  14  according to a predetermined algorithm. For example, in an embodiment operating at 220 Hz with a background voltage level at 17 V, the power supply  16  may vary the voltage level to a peak voltage level of 35 V for the peak phase of about 1.0 ms. For the same embodiment, the peak current ramp rate may be 1000 A/ms and the initial peak current may be 550 A. The power (i.e., the product of current and voltage) supplied to the welding torch  14  may remain substantially constant while the current and voltage provided by the power supply  16  may vary from the current and voltage at the arc  18  due to induction. In other words, the power supply  16  may supply the same power to the welding torch  14  through each power pulse, however the actual current and voltage levels supplied in each pulse may vary. 
         [0019]    The control circuitry  26  may be coupled by a control line  40  to an operator interface  42 . The operator interface  42  may include input devices  44  (e.g., dials, buttons, switches, and so forth) configured to provide for operator adjustment of the base unit operation. For example, input devices  44  such as dials may enable operator adjustment based on properties (e.g., size, material, and so forth) of the electrode  20  and the work piece  15 . The input devices  44  may also enable adjustment of the wire feeder  28  and the gas supply  32  through the control circuitry  26 . A display  46  may display information pertaining to the operational status of the welding system  10 , arc consistency, weld quality, and/or weld parameters. The display  46  and input devices  44  may be used together to navigate menus, adjust operational settings of the base unit  12  (e.g., input voltage, output power, pulse period, electrode feed rate, and so forth), and display pulsed waveforms. As discussed in detail below, pulsed waveforms may be stored in memory  54  of the control circuitry  26 . The input devices  44  and display  46  may be configured to provide for selection, storage, and analysis of pulsed waveforms stored in memory  54 . Indicators  48  may be used to alert the operator to conditions and the status of the welding system  10 . For example, the indicators  48  may be used to alert the operator of low electrode supply  30  or of a relatively poor weld quality. 
         [0020]    The operator interface  42  may include an accessory input  50  configured to couple a remote device  52  (e.g., a cell phone, laptop computer, welding helmet, PDA, and so forth) to the control circuitry  26 . In an embodiment, the remote device  52  may be the operator interface  42  used to monitor or control at least part of the welding system  10 . In some embodiments, the remote device  52  may be a secondary or additional operator interface  42 . The remote device  52  may be connected to the operator interface  42  and/or the control circuitry via a wired connection  51  or a wireless connection  53 . 
         [0021]    The control circuitry  26  includes the memory  54  and a processor  56 . The processor  56  may be configured to process signals and produce a pulsed waveform based on the processed signals. In some embodiments, the memory  54  may be ROM (e.g., non-volatile), RAM (e.g., volatile), magnetic storage memory, optical storage memory, or a combination thereof. The memory  54  may be configured to store one or more pulsed waveforms. Stored pulsed waveforms may be used for reference, analysis, or comparison to evaluate arc consistency and weld parameters. In addition, a variety of control regimes for various welding processes, along with associated settings and parameters may be stored in the memory  54 . The memory  54  may also store codes configured to provide a specific output (e.g., initiate wire feed, enable gas flow, etc.) during operation. 
         [0022]    In some embodiments, the control circuitry  26  may also include a network interface card (NIC)  58 . The NIC  58  may be configured for wired communications  60  or wireless communications  62  with other devices or networks  64  (e.g., the Internet). Stored pulsed waveforms may be uploaded to web pages  66  across the network  64  for remote access to other welding systems  10 . In some embodiments, certain web pages  66  may be used to access stored pulsed waveforms. Further, in some embodiments, devices (e.g., the remote devices  52 ) may access the control circuitry  26  via the network  64  to monitor and/or control operation of the base unit  12 . 
         [0023]    In an embodiment, the voltage and current sensors  36 ,  38  may transmit signals with the control circuitry  26  related to the pulsed electrical signal generating the arc  18 . The processor  56  may produce a pulsed waveform (e.g., pulsed power waveform) based on the sensed signals. In some embodiments, the pulsed waveform may be a pulsed voltage waveform or a pulsed current waveform. Voltage waveforms and current waveforms may be readily produced from the voltage and current sensors  36 ,  38 . However, other pulsed waveforms may also be produced. For example, other pulsed waveforms may be produced from a mathematical combination of the pulsed voltage waveform and the pulsed current waveform, such as pulsed power (voltage*current) or pulsed impedance (voltage/current). Pulsed power and impedance waveforms account for voltage and current simultaneously in a single waveform, and thus the processor  56  may process pulsed power or impedance waveforms more quickly than both pulsed voltage and current waveforms. The produced pulse waveforms may be stored in the memory  54  for reference, analysis, or comparison with other pulse waveforms. 
         [0024]    As illustrated, the welding torch  14  may be used to weld a work piece  15  in a weld direction  68 . As indicated by the legend, arrow  70  indicates a horizontal X-axis along the work piece  15 , arrow  72  indicates a vertical Y-axis relative to the work piece  15 , and arrow  74  indicates a horizontal Z-axis along the work piece  15 . During a weld, the welding torch  14  may be moved in the weld direction  68  and maintained at a desired relative position to the work piece  15  throughout the weld. For example, an ideal weld may be performed by maintaining the welding torch  14  in the XY plane  76  at a small angle  78  with respect to the Y-axis  72  as the welding torch  14  moves along the X-axis  70  in the weld direction  68  with no relative rotation of the welding torch  14  with respect to the X-axis  70  or Z-axis  74 . During the ideal weld, the electrode  20  may extend a certain distance from the welding torch  14 , known as electrode extension. The control circuitry  26  detects the pulsed electrical signals that produce the arc  18  for the ideal weld, and the control circuitry  26  produces one or more sample pulsed waveforms corresponding to the ideal weld. In some embodiments, the ideal pulsed waveform may be a power waveform, a current waveform, a voltage waveform, or combinations thereof, as discussed above. A pulsed waveform based at least in part on the one or more sample pulsed waveforms may be stored in the memory  54  as an ideal pulsed waveform. Multiple ideal pulsed waveforms may be stored in the memory  54 . For example, multiple ideal pulsed waveforms may correspond to various work piece, electrode, and shielding gas combinations, different operators, and different torches, and different types of welds, among others. 
         [0025]    From the one or more sample pulsed waveforms, the ideal pulsed waveform may be selected as the median pulsed waveform, the mean pulsed waveform, the most recent sampled pulsed waveform, a random sample pulsed waveform, or any pulsed waveform selected by the operator. For example, the operator may perform a six-inch weld of which the last three inches are an ideal weld. The six-inch weld may correspond to hundreds of sampled pulsed waveforms. The operator may use the operator interface to select the ideal pulsed waveform from the sampled pulsed waveforms corresponding to the last three inches by activating an input device (e.g., button). In some embodiments, the control circuitry  26  may select a typical (e.g., average, median) pulsed waveform as the ideal pulsed waveform by an algorithm. The algorithm may be stored in memory  54  and run by the processor  56 . The algorithm may determine the typical pulsed waveform to be stored as the ideal pulsed waveform from a set of sampled pulsed waveforms corresponding to the ideal weld. In an embodiment, the display  46  may display the sampled pulsed waveforms, and the input devices  44  may be used to select the ideal pulsed waveform to be stored in the memory  54 . In another embodiment, the remote device  52  may be used to select the ideal pulsed waveform from the sampled pulsed waveforms. The sampled pulsed waveforms may be stored in the memory  54  for later reference to determine the pulsed waveforms corresponding to the ideal weld. For example, the performed weld may be analyzed (e.g., subjected to X-rays, tested) to determine the quality of the performed weld. Based on the analysis, the ideal pulsed waveform may be determined as corresponding to the portion of the performed weld with a desired quality. 
         [0026]    The ideal pulsed waveform may also be stored in the memory  54  from different sources. In some embodiments, one or more ideal pulsed waveforms may be predefined in the memory  54 , corresponding to various weld parameters. In an embodiment, one or more ideal pulsed waveforms may be loaded into the memory  54  from a remote device  52  (e.g., PDA, flash drive) or the network  64  (e.g., the Internet). These ideal pulsed waveforms loaded into the memory  54  may be simulated waveforms or ideal pulsed waveforms from another welding system  10 . Ideal pulsed waveforms loaded in the memory  54  may be used for comparison to determine the quality and/or weld parameters of subsequently performed welds. 
         [0027]    A variety of conditions may affect the shape, amplitude, and duration of the pulsed waveforms. Weld parameters that affect the weld quality may also affect the pulsed waveform. The weld parameters may include, but are not limited to, positioning of the welding torch  14  relative to the work piece  15 , weld direction  68 , electrode extension, electrode properties (e.g., feed rate, composition, electrode type, and so forth), shielding gas properties (e.g., flow rate, composition, and so forth), environmental conditions (e.g., oil, moisture, or oxidation on the work piece  15 ), and condition of the base unit  12 . Welds performed with a common set of weld parameters may have similar pulsed waveforms. For example, a first weld performed under a first set of weld parameters may be represented by a first ideal pulsed waveform. A second weld performed under a second set of weld parameters may be represented by a series of sampled pulsed waveforms. A comparison of the first ideal pulsed waveform with the series of sampled pulsed waveforms may yield differences indicative of the differences between the first set of weld parameters and the second set of weld parameters. These differences may be used for diagnostic purposes and to measure weld quality of the second weld relative to the first weld. In some embodiments, the control circuitry  26  may determine the consistency of the welding arc  18  of the second weld relative to the welding arc  18  of the first weld by comparing the sampled pulsed parameters to the first ideal pulsed waveform. In an embodiment, electrode extension may be determined based on a comparison of one or more ideal pulsed waveforms corresponding to common weld parameters and known electrode extensions with a sampled pulsed waveform corresponding to the common weld parameters and an unknown electrode extension. 
         [0028]      FIG. 2  illustrates a block diagram of a method  90  for determining consistency of the welding arc  18  among welds. The first step is to obtain a reference pulsed waveform (e.g., step  92 ). In an embodiment, the reference pulsed waveform may be an ideal pulsed waveform obtained from an ideal weld performed by the welding system  10  (e.g., based on detected electrical signals from sensors, such as the voltage and current sensors  36 ,  38 ), and selected through the operator interface  42 . For example, the reference pulsed waveform may be obtained by receiving a command to store the idealized pulsed waveform via the operator interface. Alternatively, the idealized pulsed waveform may be obtained by an algorithm applied to the pulsed waveforms from an ideal weld. In some embodiments, the reference pulsed waveform may be a pulsed waveform obtained from a remote device  52 , a network  64  (e.g., Internet) coupled to the base unit  12 , or another welding system  10 . The reference pulsed waveform may be obtained from a simulation or from a reference performed weld. 
         [0029]    Once obtained, the reference pulsed waveform may be stored (e.g., step  94 ). In some embodiments, the reference pulsed waveform is stored in the memory  54  of the control circuitry  26 . In other embodiments, the reference pulsed waveform may be stored on a remote device  52  or over the network  64 . Then, the control circuitry  26  may detect a pulsed waveform (e.g., step  96 ). The pulsed waveform may be detected by detecting electrical signals relating to electrical pulses supplied to the welding torch  14 . As discussed above, in some embodiments, the control circuitry  26  may produce pulsed waveforms based on the detected electrical signals from sensors (e.g., the voltage and current sensors  36 ,  38 ). In some embodiments, the control circuitry  26  may produce a sampled pulsed waveform corresponding to each electrical pulse of a performed weld. In other embodiments, the control circuitry  26  may produce a sampled pulsed waveform based at least in part on a plurality of electrical pulses of a performed weld. For example, a sampled pulsed waveform may be produced based on the median electrical pulse of the performed weld, the mean electrical pulse of the performed weld, the most recent detected electrical pulse of the performed weld, a random electrical pulse of the performed weld, or a combinations thereof. 
         [0030]    Each pulsed waveform (e.g., ideal pulsed waveform, sampled pulsed waveform, and so forth) may be an array that includes a series of pulse amplitudes corresponding to a particular time of the pulse and/or weld. In an embodiment, the pulse period of each pulsed waveform supplied to the welding torch  14  may be between approximately 0.001 second to approximately 0.015 second, approximately 0.004 second to approximately 0.01 second, or approximately 0.005 second to approximately 0.008 second. The amplitude of each pulse may be sampled at a rate in a range of approximately 5 kHz to approximately 150 kHz, approximately 20 kHz to approximately 100 kHz, or approximately 30 kHz to approximately 50 kHz. For example, a 0.007 second electrical pulse may be sampled at a sample rate of approximately 40 kHz, resulting in approximately 280 samples per pulse. The sampled pulsed waveform may also be stored in the memory  54 . 
         [0031]    The sampled pulsed waveform may then be compared with the reference pulsed waveform (e.g., step  98 ). In some embodiments, the reference and sampled pulsed waveforms may be compared point-to-point. For example, for pulsed waveforms of substantially the same pulse period, the control circuitry  26  may quantify the difference (e.g., absolute value) between corresponding points of the reference and sampled pulsed waveforms. As discussed below with respect to  FIG. 3 , the reference pulsed waveform and the sampled pulsed waveform may have the same pulse period and general shape for the certain phases of the pulsed waveforms, yet the amplitudes may differ during other phases. In some embodiments, other properties of the pulsed waveforms, including the peak amplitude, average amplitude, pulse duration, and combinations thereof, may be compared. 
         [0032]    The next step is to determine the quality of the sampled pulsed waveform relative to the reference pulsed waveform (e.g., step  100 ). The quality may be a measure of the consistency between the sampled and reference pulsed waveforms. The reference pulsed waveform may be a pulsed waveform that corresponds to an ideal (e.g., good quality, efficient) weld. During GMAW-P welding, the electrical pulse supplied to the welding torch  14  may sufficiently melt the electrode  20  in a background phase so that it may be transferred to the work piece  15  in the transfer phase. Particular properties of the reference pulsed waveform may be indicative of weld quality. The pulsed waveform of an ideal weld may have particular amplitudes at certain times during these phases that contribute to the ideal weld. For example, the ideal pulsed power waveform of the ideal weld may supply power at certain levels to melt the electrode  20  at an ideal rate for the set of weld parameters. The ideal pulsed power waveform may ideally transfer the electrode  20 , whereas different sampled pulsed power waveforms may produce spatter and/or cause stick-slip between the electrode  20  and the work piece  15 , resulting in a relatively poor quality weld. 
         [0033]    The quality of the weld produced by the sampled pulsed waveform may be determined in step  100  based at least in part on the nature of differences between the reference waveform and one or more sampled pulsed waveforms corresponding to the performed weld. Consistency (e.g., small differences) between the sampled pulsed waveforms and the reference pulsed waveform may be used to determine that the weld corresponding to the sampled pulsed waveforms is of similar quality to the weld corresponding to the reference pulsed waveform. Inconsistency (e.g., large differences) between the sampled and reference pulsed waveforms may be used to determine that the weld corresponding to the sampled pulsed waveform is of relatively poor quality compared to the weld corresponding to the reference pulsed waveform. In some embodiments, differences at particular points (e.g., transition between background phase and transfer phase) may be used to determine the relative quality of the weld corresponding to the sampled pulsed waveforms. The determined weld quality may be a value that quantifies the difference between the sampled and reference pulsed waveforms (e.g., average absolute value difference, summed difference from each point, and so forth), a value that measures consistency and/or similarity of the sampled and reference pulsed waveforms (e.g., average percentage difference for each point, degree of fit, and so forth), a value that indicates a particular weld quality, or combinations thereof 
         [0034]    The quality of the weld corresponding to the sampled pulsed waveforms may then be displayed (e.g., step  102 ). The quality of the weld may be displayed on the operator interface  42  via the display  46  or the indicators  48 , on the remote device  52 , on the network  64 , or combinations thereof. In some embodiments, the quality determined in step  100  may be displayed as one of the values discussed above. For example, the sampled and reference waveforms may be displayed along with the value corresponding to the degree of fit between the displayed pulsed waveforms. In an embodiment, the chart of  FIG. 3  may be displayed, illustrating the ideal pulsed waveform  122  and absolute value comparisons  138 ,  140 ,  142 ,  144 . 
         [0035]    In some embodiments, the manner in which the quality is displayed may be based on whether the quality is outside set pulsed waveform difference thresholds (e.g., step  104 ). For example, a determined quality within the set pulsed waveform difference thresholds may activate an indicator  48  for good quality (e.g., light, icon) on the user interface  42  (e.g., step  106 ), whereas a determined quality outside the set pulsed waveform difference thresholds may activate an indicator  48  for relatively poor quality (e.g., step  108 ). In an embodiment, an indicator  48  may only alert the operator of relatively poor quality. Other indicators  48  may be used to alert the operator to various other quality levels of the performed weld relative to a reference weld. In some embodiments, input devices  38  may provide for adjustment of the set pulsed waveform difference thresholds. Pulsed waveform difference thresholds may be stored in the memory  54  and adjusted by the operator. Adjusting the set pulsed waveform difference thresholds may enable the welding system  10  to provide a desired level of feedback on the quality of the weld. For example, wide pulsed waveform difference thresholds may be set for a novice operator so that the welding system  10  may alert the novice operator of acceptably or unacceptably performed welds during training of the novice operator. Narrow and/or nested pulsed waveform difference thresholds may be set for a skilled operator so that the welding system  10  may alert the skilled operator as to which welding standard the performed weld satisfies. 
         [0036]    After displaying the quality, the welding system  10  and/or operator may compensate to better match the sampled pulse waveform with the reference pulsed waveform (e.g., step  110 ). The control circuitry  26  may adjust the operation of the power supply  16 , adjust the wire feeder  28 , adjust the gas supply  32 , or combinations thereof. The operator may also adjust the relative position of the welding torch  14  to the work piece  15  for a subsequent weld to compensate. 
         [0037]    Individual steps of the method  90  may be repeated to analyze the subsequent sampled pulsed waveforms corresponding to subsequent welds. In some embodiments, the obtaining and storing steps  92 ,  94  may be omitted when using previously obtained reference pulsed waveforms. Optionally, a plurality of sampled pulsed waveforms corresponding to the performed weld may be stored in the memory  54  as reference pulsed waveforms (e.g., step  94 ) and compared to each other (e.g., step  98 ). The quality determined in step  100  may be based at least in part on differences between sampled pulsed waveforms. For example, small differences between sampled pulsed waveforms corresponding to the same performed weld may be used to determine a consistent quality throughout the weld. Large differences between sampled pulsed waveforms of the same performed weld may be used to determine a change in weld quality or other weld parameter. Furthermore, quality trends may be identified through comparison (e.g., step  98 ) amongst the plurality of sampled pulsed waveforms that indicate relative changes (e.g., improvement, decline) in quality throughout a weld. 
         [0038]    Additionally, in some embodiments of the method  90 , the welding system  10  may optionally determine a weld parameter based at least in part on the comparison of step  98  (e.g., step  112 ). Some differences from the comparison may correlate with certain weld parameters such that the welding system  10  may determine the certain weld parameters based on the type of difference. For example, large differences between sampled pulsed waveforms corresponding to the same performed weld may be used to determine inconsistent relative positioning of the welding torch  14  with the work piece  15  during the course of the performed weld. The average absolute value difference for the compared points between sampled pulsed waveforms and the reference pulsed waveform may also be used to determine electrode extension. Thus, the welding system  10  may diagnose and identify factors affecting the quality of performed welds through comparison of sampled pulsed waveforms with reference pulsed waveforms and/or sampled pulsed waveforms. 
         [0039]      FIG. 3  illustrates a chart  120  of an ideal pulsed power waveform  122  and comparisons with sampled pulsed power waveforms. The Y-axis  124  of the chart  120  shows the power in watts, and the X-axis  126  shows the time in seconds. The illustrated ideal pulsed power waveform  122  has a first set of weld parameters including an electrode extension of 0.4 inches. The ideal pulsed power waveform  122  includes a peak phase  128  and a background phase  130 . The illustrated peak phase  128  has a first phase  132  in which the power supply  16  increases the current at a certain rate (e.g., 1000 A/ms), bringing up the voltage and power. During a second phase  134  of the peak phase  128 , the current reaches a desired peak and the voltage is held constant for the remainder of the peak phase  128 . During the second phase  134 , the power of the ideal pulsed power waveform  122  may continue to increase as the current increases. The welding torch  14  may transfer the melted electrode  20  to the work piece  15  during the peak phase  128 . During the third phase  136  (e.g., of the background phase  130 ), the current and voltage decrease to background levels for the duration of the background phase  130 . After the background phase  130 , another pulse period may begin. In some embodiments, each pulse period is approximately 0.007 seconds. This ideal pulsed power waveform  122  may correspond to an ideal performed weld as discussed above. Subsequent sampled pulsed power waveforms corresponding to subsequent performed welds may be compared to this ideal pulsed power waveform  122  to determine the quality of the performed welds relative to the ideal performed weld. 
         [0040]    The chart  120  includes the point-to-point comparison of four sampled pulsed power waveforms. Each of the point-to-point comparisons  138 ,  140 ,  142 ,  144  shows the absolute difference between one of the sampled pulsed power waveforms and the ideal pulsed power waveform at sampled points. In this embodiment, each of the four sampled pulsed power waveforms has the same first set of weld parameters as the ideal pulsed power waveform, except for electrode extension. The first comparison  138  relates to a first sampled pulsed power waveform from a weld performed with a 0.4 inch electrode extension. The second comparison  140  relates to a second sampled pulsed power waveform from a weld performed with a 0.6 inch electrode extension. The third comparison  142  relates to a third sampled pulsed power waveform from a weld performed with a 0.8 inch electrode extension. The fourth comparison  144  relates to a fourth sampled pulsed power waveform from a weld performed with a 1.0 inch electrode extension. The differences at each point of the first comparison  138  are smaller than the differences at each point for the second, third, and fourth comparisons  140 ,  142 , and  144 . This is because the ideal pulsed power waveform and the first sampled pulsed power waveform have the same first set of weld parameters, including electrode extension. The second, third, and fourth comparisons  140 ,  142 , and  144  show larger differences due to at least the longer electrode extension. 
         [0041]    In the illustrated embodiment, the second, third, and fourth comparisons  140 ,  142 ,  144  exhibit greater differences relative to the ideal pulsed power waveform during the second phase  134  of the peak phase  128 . During the first phase  132  of the peak phase  128 , the power supply  16  may increase the voltage and current similarly regardless of electrode extension, resulting in very similar ideal and sampled pulsed power waveforms with small differences in the comparisons  138 ,  140 ,  142 ,  144 . Electrode extension may affect the constant voltage level of the second phase  134 , which in turn affects the pulsed power waveforms. Comparisons between pulsed power waveforms relating to different electrode extensions may exhibit absolute value differences during the second phase  134  in particular. As illustrated, during the second phase  134 , the fourth comparison  144  (electrode extension=1.0 inches) exhibits the greatest absolute value difference relative the ideal pulsed power waveform (electrode extension=0.4 inches). The third comparison  142  (electrode extension=0.8 inches) has a smaller absolute value difference during the second phase  134  than the fourth comparison  144  (electrode extension=1.0 inches), but larger absolute value difference than the first comparison  138  (electrode extension=0.4 inches) and second comparison  140  (electrode extension=0.6 inches). The second comparison  140  (electrode extension=0.6 inches) has larger absolute value difference during the second phase  134  than only the first comparison (electrode extension=0.4 inches). 
         [0042]      FIG. 4  is a chart  146  illustrating the average absolute value power difference  148  of four sampled pulsed power waveforms having different electrode extensions as compared to four ideal pulsed power waveforms having different electrode extensions. The X-axis  150  represents the electrode extension of the ideal pulsed power waveform used for comparison with the sampled pulsed power waveforms. The four sampled pulsed power waveforms have common weld parameters, except each has a different electrode extension. The set of four ideal pulsed power waveforms used for comparison have the same common weld parameters, except each has a different known electrode extension. The point-to-point comparisons between the ideal and sampled pulsed power waveforms may result in absolute value differences for each point of comparison. The average absolute value differences  152 ,  154 ,  156 ,  158 , are the average of the point-to-point comparisons for the sampled pulsed power waveforms at each ideal pulsed power waveform of known electrode extension. For example, the sampled pulsed power waveform of the 0.6 inch electrode extension has the lowest average absolute value difference  154  relative to the 0.6 inch electrode extension ideal pulsed power waveform. The first set of points  152  are the average absolute value differences for the first sampled pulsed power waveform (electrode extension=0.4 inches). The second set of points  154  are the average absolute value differences for the second sampled pulsed power waveform (electrode extension=0.6 inches). The third set of points  156  are the average absolute value differences for the third sampled pulsed power waveform (electrode extension=0.8 inches). The fourth set of points  158  are the average absolute value differences for the fourth sampled pulsed power waveform (electrode extension=1.0 inches). Curves  160 ,  162 ,  164 , and  166  join points of the same set and represent estimated absolute value differences for each electrode extension as compared to ideal pulsed power waveforms having different electrode extensions. 
         [0043]      FIG. 4  illustrates the relationship between electrode extension and average absolute power difference  148  that may be used to determine electrode extension. As described above, in this embodiment, the only varied weld parameter is electrode extension. As illustrated, the minimum average absolute value power difference of the second point  154  (electrode extension=0.6 inches) corresponds to the comparison with the ideal pulsed power waveform having an electrode extension of 0.6 inches. Similarly, the minimum average absolute value difference of the third point  156  (electrode extension=0.8 inches) corresponds to the comparison with the ideal pulsed power waveform having an electrode extension of 0.8 inches. Thus, at least when weld parameters are the same except for electrode extension, the minimum average absolute value difference of a sampled pulsed power waveform corresponds to the ideal pulsed power waveform having the same electrode extension. This may be used to determine the approximate electrode extension of a sampled pulsed power waveform in real-time based on comparison with ideal pulsed power waveforms of different electrode extensions. However, determining electrode extension is one non-limiting example of how comparison of sampled pulsed waveforms with ideal pulsed waveforms may be used to determine weld parameters. In this way, the welding system  10  may be configured to determine and display weld parameters and/or weld quality to provide real-time weld feedback. 
         [0044]    The welding system and method described above herein may be used to determine the consistency of the GMAW-P welding arc and weld parameters. The welding system  10  may obtain and store reference pulsed waveforms for comparison with sampled pulsed waveforms. Reference pulsed waveforms may be obtained from any source, including performed welds, other welding systems, remote devices, networks, the Internet, or combinations thereof. The sampled pulsed waveforms from performed welds and reference pulsed waveforms may be compared to determine general differences (e.g., duration, degree of fit, and so forth) or differences at one or more points during a pulse (e.g., point-to-point, maximum, minimum, and so forth). These differences may be used to determine the quality of the performed weld relative to the weld corresponding to the reference weld. The differences may also be used to determine weld parameters. In some embodiments, sampled pulsed waveforms may be compared to multiple reference pulsed waveforms to determine the quality and/or weld parameters. The differences, quality, and weld parameters may be displayed on the operator interface, remote device, or network. The welding system may be configured to alert the operator of the weld quality and/or weld parameter based at least in part on set pulsed waveform difference thresholds. The operator may adjust these pulsed waveform difference thresholds through the activation of input devices of operator interface. 
         [0045]    While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.