Method and control device for rapid arc retraction in mig welding of an aluminum alloy welding wire

Abstract

The application provides a method and a control device for rapid arc recovery of aluminum alloy welding wire MIG welding, relates to the technical field of aluminum alloy welding, and the method for rapid arc recovery of aluminum alloy welding wire MIG welding is applied to a consumable electrode type welding method, is formed after a direct current pulse welding stage, and comprises a polarity change high filling stage, an alternating current component dynamic adjustment stage, a direct current pulse ending stage and an anti-sticking wire stage. The method reduces the welding wire loss and the replacement cost of the conducting nozzle caused by sticking, reduces the rework cost caused by arc recovery defects, improves the arc recovery efficiency, can be directly integrated into an existing MIG welding device, does not need to be large-scale reformed, and is suitable for existing mainstream working methods such as pulse welding and double pulse welding.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy welding technology, and more specifically, to a method and control device for rapid arc termination in MIG welding of aluminum alloy welding wire. Background Technology

[0002] Metal Inert Gas Welding (MIG) technology for aluminum alloys has become a core welding technology in the manufacturing of high-end aluminum alloy components due to its advantages such as high welding efficiency, good weld formation, thorough oxide film removal, and minimal damage to the workpiece. It is widely used in industries such as aerospace, rail vehicles, and new energy vehicle manufacturing. With the rapid development of the new energy vehicle industry, the requirements for welding quality and efficiency of key components such as battery boxes are constantly increasing. 1.6mm diameter aluminum alloy welding wire, with its advantages of low heat input, fast welding speed, and deep penetration, is gradually becoming the preferred welding wire for welding components such as battery boxes.

[0003] Currently, the main welding methods for 1.6mm aluminum alloy welding wire in the industry are pulse welding and double-pulse welding, but arc termination control technology is relatively lagging behind, and related research is scarce. Existing arc termination technology mainly follows the arc termination scheme of 1.2mm welding wire, without fully considering the characteristics of 1.6mm welding wire, such as large diameter, low resistance, and fast cooling rate. This leads to many defects in the arc termination process: short-circuit arc termination is prone to wire sticking, low-current pulse arc termination has low efficiency, arc crater is concave, and cracks are easily generated, which seriously affects welding quality and production cycle. Summary of the Invention

[0004] The present invention aims to solve the problems of easy wire sticking during short-circuit arc termination and low arc termination efficiency of 1.6mm aluminum alloy welding wire with small current pulse.

[0005] To address the above problems, this invention provides a method and control device for rapid arc termination in MIG welding of aluminum alloy welding wire.

[0006] In a first aspect, the present invention provides a method for rapid arc termination in MIG welding of aluminum alloy welding wire, which is applied to a consumable electrode welding method and is formed after the DC pulse welding stage, including a variable polarity high fill stage, an AC composition dynamic adjustment stage, a DC pulse termination stage and an anti-sticking stage. During the high-filling polarity stage, DC pulse welding is switched to MIG welding with a polarity-variable ratio of 25% to 35%, and welding is performed at the first welding current, which is 100% to 110% of the welding current in the DC pulse welding stage. During the dynamic adjustment phase of the AC component, the EN ratio decreases in stages until it drops to 0%, thus completing the dynamic adjustment phase of the AC component. During the DC pulse termination phase, the variable polarity MIG welding is switched to pure DC pulse welding, and welding is performed under the second welding current to maintain the molten pool temperature; wherein, the second welding current is less than the first welding current. During the anti-sticking stage, the voltage and current between the welding wire and the base material are monitored in real time. If the voltage increases, the welding current and wire feeding are cut off, and the welding ends. If the voltage is less than 5V or the current fluctuates abnormally, it is determined that the welding wire sticks to the molten pool. A non-zero preset voltage is applied to the welding torch, and the welding wire is pulled back 1 mm to 3 mm at the first speed to break the sticking point and separate the welding wire from the weld bead.

[0007] The EN ratio (Electrode Negative percentage) refers to the proportion of time the electrode is in a negative polarity (i.e., electrons flow from the welding torch to the workpiece) within a current cycle.

[0008] Optionally, during the dynamic adjustment phase of the AC component, the EN ratio is reduced to 15% to 22% and maintained for 50 ms to 80 ms; then reduced to 5% to 10% and maintained for 30 ms to 50 ms; and finally reduced to 0%, completing the dynamic adjustment phase of the AC component.

[0009] Optionally, the steps for the segmented step-down of the EN ratio include: determining the reference arc voltage based on the preset current-arc voltage curve and the user's arc length correction value; acquiring the welding arc voltage in real time; the difference between the welding arc voltage and the reference arc voltage is the arc voltage deviation; if the arc voltage deviation > 0, the rate of decrease of the EN ratio is reduced or the EN ratio is kept constant; if the arc voltage deviation < 0, the rate of decrease of the EN ratio is accelerated until the EN ratio drops to 0%.

[0010] Optionally, the variable polarity high fill stage is initiated 5 to 10 mm before the end of the DC pulse welding stage.

[0011] Optionally, when the high-fill stage of variable polarity is started, the welding wire is fed forward at a first speed. During the high-fill stage of variable polarity and the dynamic adjustment stage of AC composition, the wire feeding speed continuously decreases to a second speed. During the DC pulse termination stage, the welding wire is fed forward at a constant third speed. Wherein, the first speed ≥ the wire feeding speed of the DC pulse welding stage > the second speed > the third speed > 0.

[0012] Optionally, the duration of the DC pulse termination phase is from 100 ms to 300 ms.

[0013] Optionally, the first welding current is 80 A to 280 A, and the second welding current is 60 A to 80 A.

[0014] Optionally, during the anti-sticking stage, the preset voltage is 40 V to 50 V.

[0015] Optionally, during the anti-sticking stage, if the voltage is <5V or the current fluctuates abnormally, it is determined that the welding wire is sticking to the molten pool. The welding gun outputs one to three strong pulse currents with a peak value of 300 A to 350 A, lasting for 1 ms to 3 ms, to separate the welding wire from the weld bead.

[0016] In a second aspect, the present invention provides a control device for rapid arc termination in MIG welding of aluminum alloy welding wire, for operating the method for achieving rapid arc termination in MIG welding of aluminum alloy welding wire as described above. The control device includes a welding control circuit and a servo motor controlling the wire drawing welding gun, respectively connected to the electrode. The welding control circuit is used to receive detection signals and output control commands; The servo motor controls the wire drawing welding torch to control the feed speed and feed direction of the welding wire; Electrodes are used to apply current to the welding area via welding wire; The welding control circuit includes: The DC pulse current output module is used to output a DC welding current with a preset peak current, base current, pulse frequency and duration to the electrode during the DC pulse termination phase in order to achieve molten pool heat compensation. The variable polarity pulse current output module is used to output a variable polarity pulse current with a pre-set EN ratio, welding current and pulse frequency to the electrode during the variable polarity high fill stage and the AC component dynamic adjustment stage. The arc voltage / current detection unit includes an arc voltage sensor and a current sensor. The arc voltage sensor is used to monitor the arc voltage change corresponding to the arc length in real time, and the current sensor is used to monitor the fluctuation of the welding current in real time. The anti-sticking control module receives the detection signal from the arc voltage / current detection unit to determine whether sticking has occurred. If sticking occurs, it immediately outputs a preset voltage control command and a wire retraction control command to control the output of the strong pulse current.

[0017] The beneficial effects of the method and control device for rapid arc termination in MIG welding of aluminum alloy welding wire of the present invention are as follows: First, the EN ratio is 25% to 35%. By adjusting the AC component ratio of the arc, the welding heat input is controlled. The first welding current is 100% to 110% of the welding current in the DC pulse welding stage, achieving a balance of "high current and low heat input". The welding current is maintained or slightly higher than that in the normal DC pulse welding stage to ensure sufficient filler volume and avoid crater depression. Utilizing the characteristics of low heat input and high filler efficiency of variable polarity MIG welding, the welding wire metal is rapidly filled to the arc termination point with a high current during the window period when the molten pool has sufficient heat, so that the weld bead at the arc termination point is full and free of crater depression, while avoiding overheating or excessive cooling of the molten pool, effectively suppressing the generation of arc termination cracks.

[0018] Secondly, the dynamic adjustment stage of the AC composition controls the arc AC composition, pulse parameters, and welding wire movement state by adjusting the EN ratio in a stepwise manner. This adapts in real time to the cooling rate of the molten pool and the filling requirements, precisely controlling the heat input during the arc termination process. This allows the molten pool temperature to decrease slowly, reducing welding heat input and preventing the molten pool from overheating and burning the workpiece. At the same time, the stepwise adjustment achieves a smooth attenuation of heat input, avoiding stress concentration and crack formation caused by sudden changes in the cooling rate of the molten pool. This ensures arc stability during the arc termination process, avoiding problems such as arc length loss and spatter, resulting in good consistency in arc termination quality. Furthermore, continuous replenishment of filler metal ensures that the arc crater is fully filled, improving the appearance quality of the arc termination.

[0019] Secondly, during the DC pulse finishing stage, the variable polarity MIG welding is switched to pure DC pulse welding, the welding current is reduced, and the molten pool is ensured to cool slowly and evenly; the temperature of the molten pool is maintained to avoid rapid solidification and shrinkage of the molten pool, further filling the arc crater, ensuring that the weld bead at the end of the arc is full and without depression, while reducing stress concentration and preventing crack formation.

[0020] Finally, in the anti-sticking stage, after the DC pulse thermal compensation ends and before the arc is extinguished, the voltage and current between the welding wire and the base material are monitored in real time. If the voltage increases, it indicates that the arc is burning normally and the welding wire is not sticking. In this case, the welding current and wire feeding are cut off normally, and the welding ends. If the voltage is <5V and close to the short-circuit voltage, or the current fluctuates abnormally, it is judged that the welding wire is sticking to the molten pool. Once sticking is judged, a non-zero preset voltage is immediately applied to the welding torch to generate arc force, re-ignite the arc, and separate the sticking point. At the same time as the preset voltage is applied, the welding wire is retracted at the first speed by 1 mm to 3 mm, and the sticking point is broken by mechanical force to ensure that the welding wire and the weld bead are cleanly separated. Through the logic of "state detection + active intervention", the sticking defect is fundamentally eliminated, ensuring a smooth arc termination process, avoiding welding wire breakage and contact tip damage, and significantly reducing the arc termination defect rate.

[0021] This method reduces wire loss and contact tip replacement costs caused by wire sticking, and lowers rework costs due to arc termination defects. At the same time, it improves arc termination efficiency and can be directly integrated into existing MIG welding equipment without large-scale equipment modification. It is compatible with existing mainstream methods such as pulse welding and double pulse welding. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the welding current waveforms at each stage of the rapid arc termination method for MIG welding of aluminum alloy welding wire according to an embodiment of the present invention. Figure 2 The waveform diagrams of wire feed speed, welding current, and EN ratio are shown for the DC pulse welding stage, variable polarity high fill stage, AC component dynamic adjustment stage, and DC pulse termination stage of this invention. Figure 3This is a schematic diagram of the current and voltage waveforms during the anti-sticking stage of an embodiment of the present invention; Figure 4 This is a schematic diagram of the control device for rapid arc termination in MIG welding of aluminum alloy welding wire according to an embodiment of the present invention. Detailed Implementation

[0023] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this invention's description is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in this invention are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0025] To address the problems existing in the aforementioned related technologies, embodiments of the present invention provide a method and control device for rapid arc termination in MIG welding of aluminum alloy welding wire.

[0026] like Figure 1 As shown, an embodiment of the present invention provides a method for rapid arc termination in MIG welding of aluminum alloy welding wire, which is applied to a consumable electrode welding method and is formed after the DC pulse welding stage. It includes a variable polarity high fill stage, an AC composition dynamic adjustment stage, a DC pulse termination stage, and an anti-sticking stage. like Figure 2As shown, in the high-fill stage of variable polarity (T1), DC pulse welding is switched to variable polarity MIG welding, with an EN ratio of 25% to 35%, and welding is performed under the first welding current, where the first welding current is 100% to 110% of the welding current in the DC pulse welding stage; the EN ratio (Electrode Negative percentage) refers to the proportion of time that the electrode is in negative polarity (i.e., electrons flow from the welding gun to the workpiece) within one current cycle; During the dynamic adjustment phase of the AC component (T2), the EN ratio decreases in stages until it drops to 0%, thus completing the dynamic adjustment phase of the AC component. During the DC pulse finishing stage (T3), the variable polarity MIG welding is switched to pure DC pulse welding, and welding is performed under the second welding current to maintain the molten pool temperature; wherein, the second welding current is less than the first welding current. like Figure 3 As shown, in the anti-sticking stage (T4), the voltage and current between the welding wire and the base material are detected in real time. If the voltage increases, the welding current and wire feeding are cut off, and the welding ends. If the voltage is <5V or the current fluctuates abnormally, it is determined that the welding wire sticks to the molten pool. A non-zero preset voltage is applied to the welding torch, and the welding wire is pulled back 1 mm to 3 mm at the first speed to break the sticking point and separate the welding wire from the weld bead.

[0027] Specifically, MIG welding refers to gas metal arc welding, which uses a consumable electrode as the welding wire. Under the protection of an inert gas, the heat of the electric arc melts the welding wire and the workpiece to achieve a connection.

[0028] In AC tungsten inert gas welding (AC-TIG) or AC metal inert gas welding (AC-MIG).

[0029] Figure 1 and Figure 2 In this context, peak current (Ipp) and base current (Ipb) refer to the welding modes that periodically switch between high and low current during the welding process, with both output currents being Is.

[0030] AC pulse refers to alternating current pulse, which is a pulsed current whose direction changes periodically with time, and whose average value over one cycle is zero. The waveform of alternating current is usually a sine wave, but it can also be a triangular wave, a square wave, or other waveforms.

[0031] In this embodiment, firstly, the EN ratio is 25% to 35%. By adjusting the proportion of AC component in the arc, the welding heat input is controlled. The first welding current is 100% to 110% of the welding current in the DC pulse welding stage, achieving a balance of "high current and low heat input". The welding current is maintained at or slightly higher than that in the normal DC pulse welding stage to ensure sufficient filler volume and avoid crater depression. Utilizing the characteristics of low heat input and high filler efficiency of variable polarity MIG welding, during the window period when the molten pool has sufficient heat, the welding wire metal is rapidly filled to the arc termination point with a high current, making the weld bead at the arc termination point full and free of crater depression, while avoiding overheating or excessive cooling of the molten pool, effectively suppressing the generation of arc termination cracks.

[0032] Secondly, the dynamic adjustment stage of the AC composition controls the arc AC composition, pulse parameters, and welding wire movement state by adjusting the EN ratio in a stepwise manner. This adapts in real time to the cooling rate of the molten pool and the filling requirements, precisely controlling the heat input during the arc termination process. This allows the molten pool temperature to decrease slowly, reducing welding heat input and preventing the molten pool from overheating and burning the workpiece. At the same time, the stepwise adjustment achieves a smooth attenuation of heat input, avoiding stress concentration and crack formation caused by sudden changes in the cooling rate of the molten pool. This ensures arc stability during the arc termination process, avoiding problems such as arc length loss and spatter, resulting in good consistency in arc termination quality. Furthermore, continuous replenishment of filler metal ensures that the arc crater is fully filled, improving the appearance quality of the arc termination.

[0033] Secondly, during the DC pulse finishing stage, the variable polarity MIG welding is switched to pure DC pulse welding, the welding current is reduced, and the molten pool is ensured to cool slowly and evenly; the temperature of the molten pool is maintained to avoid rapid solidification and shrinkage of the molten pool, further filling the arc crater, ensuring that the weld bead at the end of the arc is full and without depression, while reducing stress concentration and preventing crack formation.

[0034] Finally, in the anti-sticking stage, after the DC pulse thermal compensation ends and before the arc is extinguished, the voltage and current between the welding wire and the base material are monitored in real time. If the voltage increases, it indicates that the arc is burning normally and the welding wire is not sticking. In this case, the welding current and wire feeding are cut off normally, and the welding ends. If the voltage is <5V and close to the short-circuit voltage, or the current fluctuates abnormally, it is judged that the welding wire is sticking to the molten pool. Once sticking is judged, a non-zero preset voltage is immediately applied to the welding torch to generate arc force, re-ignite the arc, and separate the sticking point. At the same time as the preset voltage is applied, the welding wire is retracted at the first speed by 1 mm to 3 mm, and the sticking point is broken by mechanical force to ensure that the welding wire and the weld bead are cleanly separated. Through the logic of "state detection + active intervention", the sticking defect is fundamentally eliminated, ensuring a smooth arc termination process, avoiding welding wire breakage and contact tip damage, and significantly reducing the arc termination defect rate.

[0035] This method reduces wire loss and contact tip replacement costs caused by wire sticking, and lowers rework costs due to arc termination defects. It also improves arc termination efficiency and can be directly integrated into existing MIG welding equipment without large-scale equipment modifications. It is compatible with existing mainstream methods such as pulse welding and double pulse welding. Furthermore, the arc termination parameters can be flexibly adjusted according to aluminum alloy workpieces of different thicknesses and materials (especially aluminum alloys for battery boxes), making it highly practical and valuable for widespread application.

[0036] Optionally, during the dynamic adjustment phase of the AC component, the EN ratio is reduced to 15% to 22% and maintained for 50 ms to 80 ms; then reduced to 5% to 10% and maintained for 30 ms to 50 ms; and finally reduced to 0%, completing the dynamic adjustment phase of the AC component.

[0037] In this optional embodiment, the EN ratio is reduced from the initial preset value to 15% to 22% and maintained for 50 ms to 80 ms to ensure sufficient filling; then reduced to 5% to 10% and maintained for 30 ms to 50 ms to gradually reduce heat input; finally reduced to 0% to complete the AC composition adjustment and transition to the next stage; through step-by-step adjustment, a smooth decay of heat input is achieved, avoiding sudden changes in the cooling rate of the molten pool.

[0038] Optionally, the steps for the segmented step-down of the EN ratio include: determining the reference arc voltage based on the preset current-arc voltage curve and the user's arc length correction value; acquiring the welding arc voltage in real time; the difference between the welding arc voltage and the reference arc voltage is the arc voltage deviation; if the arc voltage deviation > 0, the rate of decrease of the EN ratio is reduced or the EN ratio is kept constant; if the arc voltage deviation < 0, the rate of decrease of the EN ratio is accelerated until the EN ratio drops to 0%.

[0039] Specifically, the welding arc voltage (Uw) is collected in real time, and the state of the molten pool is monitored by an arc voltage sensor. The reference arc voltage (Ur=Ud+Us) is determined based on the preset current-arc voltage curve (Ud=a×I+b, where Ud is the basic arc voltage, I is the welding current, and a and b are empirical coefficients, which are preset according to the welding wire type, workpiece material, etc.) and the user's arc length correction value (Us). The arc voltage deviation ΔU=Uw-Ur is then calculated.

[0040] In this optional embodiment, if the arc pressure deviation ΔU > 0, it indicates that the arc length has increased and the heat of the molten pool is insufficient. Therefore, the rate of decrease of the EN ratio is reduced or the EN ratio is maintained briefly to increase heat input and ensure stable molten pool temperature. If the arc pressure deviation ΔU < 0, it indicates that the arc length has decreased and the molten pool is overheated. Therefore, the rate of decrease of the EN ratio is accelerated to rapidly reduce heat input and prevent workpiece burn-out. Through closed-loop adjustment, adaptive control of heat input is achieved to meet the needs of different welding scenarios. Dynamic adjustment of the arc AC composition precisely controls the heat input during the arc termination process, causing the molten pool temperature to decrease slowly, avoiding stress concentration and crack formation caused by rapid cooling. Simultaneously, continuous replenishment of filler metal ensures the crater is fully filled, improving the appearance quality of the terminated arc.

[0041] Optionally, the variable polarity high fill stage is initiated 5 to 10 mm before the end of the DC pulse welding stage.

[0042] In this optional embodiment, the arc termination process is initiated 5 mm to 10 mm in advance, allowing for an earlier attenuation transition, smooth arc decay, and avoiding sudden changes in current and voltage. This short distance is used for slow arc termination, ensuring a stable finish and continuous replenishment of molten metal to fill the crater at the weld end, preventing crater defects. This prevents sudden arc interruption at the end point from causing a sharp drop in weld penetration, incomplete fusion, or undercut. The result is crater-free welds with good weld formation, minimal spatter, fewer cracks, and more stable weld quality.

[0043] Optionally, such as Figure 2 As shown, when the high-fill stage of variable polarity is started, the welding wire is fed forward at the first speed. During the high-fill stage of variable polarity and the dynamic adjustment stage of AC composition, the wire feeding speed continuously decreases to the second speed. During the DC pulse end stage, the welding wire is fed forward at a constant third speed. Among them, the first speed (Ws1) ≥ the wire feeding speed (Ws2) of the DC pulse welding stage > the second speed (Ws3) > the third speed (Ws4) > 0.

[0044] Specifically, speed > 0 means that the forward feed direction of the welding wire is defined as the positive direction. Speed ​​< 0 means that the reverse withdrawal direction of the welding wire is defined as the negative direction.

[0045] In this optional embodiment, the high-fill stage with variable polarity maintains the normal welding speed of the DC pulse welding stage without reducing the speed, ensuring arc termination efficiency and achieving high-speed arc termination. In subsequent stages, the wire feed speed is gradually reduced, abandoning the traditional operation of reducing welding speed before arc termination. Through high-current, low-heat input control logic, the arc termination time is significantly shortened while ensuring arc termination quality, achieving high-speed arc termination with 1.6mm welding wire without significantly reducing the welding speed, resulting in short arc termination time and high efficiency. The entire arc termination process in the DC pulse termination stage maintains the third-speed wire feed, without reducing the welding speed, and the total arc termination time is controlled between 300 ms and 500 ms, achieving high-speed arc termination.

[0046] Optionally, the duration of the DC pulse termination phase is from 100 ms to 300 ms.

[0047] Specifically, the duration of the DC pulse termination phase can be adjusted according to the workpiece thickness.

[0048] In this optional embodiment, the arc-ending time during the DC pulse termination phase is highly efficient.

[0049] Optionally, the first welding current is 80 A to 280 A, and the second welding current is 60 A to 80 A.

[0050] In this optional embodiment, the welding current during the high-filling stage with variable polarity is 80 A to 280 A, which is maintained or slightly higher than the welding current during the normal DC pulse welding stage, to ensure sufficient fill and avoid crater depression; the welding current during the DC pulse termination stage is reduced to 60 A to 80 A to ensure slow and uniform cooling of the molten pool, to avoid rapid solidification and shrinkage of the molten pool, to further fill the crater, to ensure a full and depression-free weld at the end of the arc, and to reduce stress concentration and prevent crack formation.

[0051] Optionally, during the anti-sticking stage, the preset voltage is 40 V to 50 V.

[0052] In this optional embodiment, applying a preset voltage of 40 V to 50 V to the welding torch generates an arc force to attempt to re-ignite the arc and separate the sticky wire points. When the voltage exceeds 40 V, the electric field strength is sufficiently high, allowing the welding wire tip to instantly break down and form an arc. The arc force and metal vaporization force "bounce" the sticky wire points away. However, exceeding 50 V results in excessive voltage withstand pressure on the welding machine's internal power devices and drive circuits, leading to excessive instantaneous energy that could burn the workpiece, break the welding wire, and cause large spatter. Setting the voltage to 40 V to 50 V ensures sufficient electric field strength to break down and ignite the arc in a short-circuit sticky state, generating sufficient arc force to separate the welding wire; and it also prevents excessively high voltage from damaging the power devices and burning the workpiece and welding wire.

[0053] Optionally, such as Figure 3 As shown, during the anti-sticking stage, if the voltage is <5V or the current fluctuates abnormally, it is determined that the welding wire sticks to the molten pool. The welding gun outputs one to three strong pulse currents with a peak value of 300 A to 350 A, lasting for 1 ms to 3 ms, to separate the welding wire from the weld bead.

[0054] In this optional embodiment, one to three strong pulse currents are output for 1 to 3 ms to enhance the arc force, further ensure complete separation of the sticky wire points, avoid residual sticky wire, ensure a smooth arc termination process, and avoid wire breakage and contact tip damage.

[0055] like Figure 4As shown, another embodiment of the present invention provides a control device for rapid arc termination in MIG welding of aluminum alloy welding wire, which is used to operate and realize the method of rapid arc termination in MIG welding of aluminum alloy welding wire as described above. The control device includes a welding control circuit and a servo motor controlling the wire drawing welding gun respectively connected to the electrode. The welding control circuit is used to receive detection signals and output control commands; The servo motor controls the wire drawing welding torch to control the feed speed and feed direction of the welding wire; Electrodes are used to apply current to the welding area via welding wire; The welding control circuit includes: The DC pulse current output module is used to output a DC welding current with a preset peak current, base current, pulse frequency and duration to the electrode during the DC pulse termination phase in order to achieve molten pool heat compensation. The variable polarity pulse current output module is used to output a variable polarity pulse current with a pre-set EN ratio, welding current and pulse frequency to the electrode during the variable polarity high fill stage and the AC component dynamic adjustment stage. The arc voltage / current detection unit includes an arc voltage sensor and a current sensor. The arc voltage sensor is used to monitor the arc voltage change corresponding to the arc length in real time, and the current sensor is used to monitor the fluctuation of the welding current in real time. The anti-sticking control module receives the detection signal from the arc voltage / current detection unit to determine whether sticking has occurred. If sticking occurs, it immediately outputs a preset voltage control command and a wire retraction control command to control the output of the strong pulse current.

[0056] Specifically, the welding control circuit is connected to the servo wire feeding mechanism, the arc voltage / current detection unit, and the welding electrode to receive detection signals and output control commands, thereby achieving precise parameter control in the three stages of arc termination. The welding control circuit includes four functional modules: (1) Variable polarity pulse current output module: used to output a preset variable polarity pulse current to the welding electrode during the variable polarity high fill stage and the AC component dynamic adjustment stage. It can accurately adjust parameters such as EN ratio (25%-35% adjustable), welding current (80-200A adjustable), and pulse frequency to realize the control logic of high current and low heat input. (2) DC pulse current output module: used to output DC pulse current to the welding electrode during the DC pulse end stage. The peak pulse current, base current, pulse frequency and duration can be adjusted to achieve molten pool heat compensation. (3) Anti-sticking wire control module: used to receive the detection signal from the arc voltage / current detection unit, determine whether sticking wire has occurred, and if sticking wire occurs, immediately output the preset voltage control command and the wire retraction control command to complete the anti-sticking wire action in coordination. At the same time, it can control the output of strong pulse current. (4) The arc voltage / current detection unit includes an arc voltage sensor and a current sensor, which are electrically connected to the welding control circuit. It is used to collect the welding arc voltage (Uw) and welding current signals in real time during the arc termination process, and transmit the detection signals to the welding control circuit to provide data support for dynamic adjustment of AC composition and wire sticking judgment. Arc voltage sensor: Real-time monitoring of arc voltage changes corresponding to arc length, with an accuracy of ≤±0.1V, ensuring the accuracy of arc voltage deviation calculation; Current sensor: Real-time monitoring of welding current fluctuations with an accuracy of ≤±1A, assisting in judging the contact state between the welding wire and the molten pool, and avoiding misjudgment of wire sticking.

[0057] The servo motor is electrically connected to the welding control circuit to precisely control the feed speed, feed direction, and retraction of the 1.6mm aluminum alloy welding wire. It adapts to the control requirements of each stage of arc termination, ensuring the smoothness and accuracy of wire feeding and retraction, and avoiding problems such as wire scraping and unstable wire feeding. (1) Normal arc termination stage: Maintain normal wire feeding speed, match with welding current and welding speed, and ensure sufficient filler volume; (2) Anti-sticking stage: can be quickly switched to the retraction mode, and perform a rapid retraction action of -5mm / s to -10mm / s, with a retraction distance of 1 ms to 3 ms. The retraction speed and retraction distance can be preset and adjusted by the welding control circuit. The electrode is used to conduct welding current to the welding area through 1.6mm aluminum alloy welding wire, generate an electric arc, and provide a heat source for the arc termination process. The welding electrode adopts a conductive tip adapted to 1.6mm welding wire to reduce wire scraping and wire feeding resistance and ensure stable current conduction.

[0058] In this embodiment, it can be integrated into existing MIG welding equipment without large-scale hardware modification. Its structure includes a welding control circuit, a wire feeding mechanism, an arc voltage / current detection unit, a welding electrode and a shielding gas supply unit. All components work together to achieve precise control of the arc termination process.

[0059] The present invention will be further described below with reference to specific embodiments.

[0060] Example 1: Rapid arc termination during MIG welding with 1.6mm diameter aluminum alloy welding wire.

[0061] (1) Welded workpiece: 6061 aluminum alloy plate (a common material for battery boxes of new energy vehicles), 3mm thick, butt joint, no gap; (2) Welding wire parameters: 1.6mm diameter 4043 aluminum alloy welding wire, wire extension length 18-22mm; (3) Welding equipment: Existing MIG welding equipment, integrating the arc-extinguishing device described in this invention, with argon as the protective gas and a flow rate of 20L / min; (4) Arc termination parameter settings: High-fill stage with variable polarity: EN ratio 30%, welding current 180A (normal welding current 160A in DC pulse welding stage), welding speed maintained at 12mm / s (normal welding speed), duration 150ms; The dynamic adjustment phase of the communication component: a segmented step-down strategy is adopted, with the EN ratio decreasing from 30% to 20% (maintained for 60ms), then to 10% (maintained for 40ms), and finally to 0%; DC pulse finishing and anti-sticking stage: DC pulse current 80A, heat compensation duration 200ms; welding voltage 19V, retraction speed -8mm / s, retraction distance 2mm; total arc termination time 400ms.

[0062] Comparative Example 1: Arc termination using 1.6mm diameter aluminum alloy welding wire.

[0063] (1) Welded workpiece: 6061 aluminum alloy plate (a common material for battery boxes of new energy vehicles), 3mm thick, butt joint, no gap; (2) Welding wire parameters: 1.6mm diameter 4043 aluminum alloy welding wire, wire extension length 18-22mm; (3) Welding equipment: Existing MIG welding equipment, integrating the arc-extinguishing device described in this invention, with argon as the protective gas and a flow rate of 20L / min; (4) Arc termination parameter settings: The existing low-current pulse arc termination technology is adopted, with an arc termination current of 80A, the welding speed is reduced to 8mm / s before arc termination, and the arc termination time is 800ms.

[0064] Effect Example (1) Arc termination efficiency: The total arc termination time of Example 1 is 400ms, compared with the total arc termination time of Comparative Example 1 of 800ms. The arc termination efficiency of Example 1 is increased by 50%, without the need to reduce the welding speed, effectively improving the welding cycle time; (2) Arc termination quality: The arc termination of Example 1 is full, without arc crater depression, without arc termination crack, and the weld appearance is flat, which meets the welding quality standards for new energy vehicle battery boxes. (3) Wire adhesion: There was no wire adhesion in Example 1. The welding wire and the weld bead were separated cleanly, and there was no wire breakage or contact tip damage. The feasibility and superiority of the arc-extinguishing method and device in Embodiment 1 of the present invention have been verified. It can effectively solve the core pain point of arc extinguishing of 1.6mm aluminum alloy welding wire, take into account both arc extinguishing quality and efficiency, and adapt to the welding needs of high-end aluminum alloy components such as new energy vehicle battery boxes.

[0065] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for rapid arc termination in MIG welding of aluminum alloy welding wire, characterized in that, The welding method applied to consumable electrodes is formed after the DC pulse welding stage, including the variable polarity high fill stage, the AC component dynamic adjustment stage, the DC pulse tailing stage, and the anti-sticking stage. During the high-filling polarity stage, DC pulse welding is switched to MIG welding with a polarity changeover ratio of 25% to 35%, and welding is performed at a first welding current, wherein the first welding current is 100% to 110% of the welding current of the DC pulse welding stage. During the dynamic adjustment phase of the AC component, the EN ratio decreases in stages until it drops to 0%, thus completing the dynamic adjustment phase of the AC component. During the DC pulse termination phase, the variable polarity MIG welding is switched to pure DC pulse welding, and welding is performed under a second welding current to maintain the molten pool temperature; wherein, the second welding current is less than the first welding current. During the anti-sticking stage, the voltage and current between the welding wire and the base material are monitored in real time. If the voltage increases, the welding current and wire feeding are cut off, and the welding ends. If the voltage is less than 5V or the current fluctuates abnormally, it is determined that the welding wire sticks to the molten pool. A non-zero preset voltage is applied to the welding torch, and the welding wire is pulled back 1 mm to 3 mm at a first speed to break the sticking point and separate the welding wire from the weld bead.

2. The method for rapid arc termination in MIG welding of aluminum alloy welding wire according to claim 1, characterized in that, During the dynamic adjustment phase of the AC component, the EN ratio decreases to 15% to 22% and is maintained for 50 ms to 80 ms; then decreases to 5% to 10% and is maintained for 30 ms to 50 ms; finally, it decreases to 0%, completing the dynamic adjustment phase of the AC component.

3. The method for rapid arc termination in MIG welding of aluminum alloy welding wire according to claim 1, characterized in that, The step-by-step reduction of the EN ratio includes: determining a reference arc voltage based on a preset current-arc voltage curve and a user arc length correction value; acquiring the welding arc voltage in real time; the difference between the welding arc voltage and the reference arc voltage is the arc voltage deviation; if the arc voltage deviation > 0, the rate of decrease of the EN ratio is reduced or the EN ratio is kept constant; if the arc voltage deviation < 0, the rate of decrease of the EN ratio is accelerated until the EN ratio drops to 0%.

4. The method for rapid arc termination in MIG welding of aluminum alloy welding wire according to claim 1, characterized in that, The variable polarity high fill stage is initiated 5 to 10 mm before the end of the DC pulse welding stage.

5. The method for rapid arc termination in MIG welding of aluminum alloy welding wire according to claim 1, characterized in that, When the variable polarity high fill stage is started, the welding wire is fed forward at a first speed. During the variable polarity high fill stage and the AC component dynamic adjustment stage, the wire feeding speed continuously decreases to a second speed. During the DC pulse termination stage, the welding wire is fed forward at a constant third speed. Wherein, the first speed ≥ the wire feeding speed of the DC pulse welding stage > the second speed > the third speed > 0.

6. The method for rapid arc termination in MIG welding of aluminum alloy welding wire according to claim 1, characterized in that, The duration of the DC pulse termination phase is from 100 ms to 300 ms.

7. The method for rapid arc termination in MIG welding of aluminum alloy welding wire according to claim 1, characterized in that, The first welding current is 80 A to 280 A, and the second welding current is 60 A to 80 A.

8. The method for rapid arc termination in MIG welding of aluminum alloy welding wire according to claim 1, characterized in that, During the anti-sticking stage, the preset voltage is 40 V to 50 V.

9. The method for rapid arc termination in MIG welding of aluminum alloy welding wire according to claim 1, characterized in that, During the anti-sticking stage, if the voltage is less than 5V or the current fluctuates abnormally, it is determined that the welding wire sticks to the molten pool. The welding gun outputs one to three strong pulse currents with a peak value of 300 A to 350 A, lasting for 1 ms to 3 ms, to separate the welding wire from the weld bead.

10. A control device for rapid arc termination in MIG welding of aluminum alloy welding wire, used to operate and implement the method for rapid arc termination in MIG welding of aluminum alloy welding wire as described in any one of claims 1-9, characterized in that, The control device includes a welding control circuit connected to the electrode and a servo motor controlling the wire drawing welding gun. The welding control circuit is used to receive detection signals and output control commands; The servo motor controls the wire drawing welding gun to control the feeding speed and feeding direction of the welding wire; The electrode is used to apply current to the welding area through the welding wire; The welding control circuit includes: A DC pulse current output module is used to output a DC welding current with a preset peak current, base current, pulse frequency and duration to the electrode during the DC pulse termination phase, so as to achieve molten pool heat compensation. A variable polarity pulse current output module is used to output a variable polarity pulse current with a pre-set EN ratio, welding current and pulse frequency to the electrode during the variable polarity high fill stage and the AC component dynamic adjustment stage. An arc voltage / current detection unit includes an arc voltage sensor and a current sensor. The arc voltage sensor is used to monitor the arc voltage change corresponding to the arc length in real time, and the current sensor is used to monitor the fluctuation of the welding current in real time. The anti-sticking control module is used to receive the detection signal from the arc voltage / current detection unit, determine whether sticking has occurred, and if sticking occurs, immediately output a preset voltage control command and a wire retraction control command to control the output of the strong pulse current.

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