A welding stability identification system for impact welding dissimilar metal wires

Abstract

The application discloses a kind of welding stability identification systems of impact welding dissimilar metal wire, it is related to metal forming manufacturing technical field, including power supply, transformer, welding device and controller, power supply is connected between the input of transformer by high-frequency inverter circuit, the output of transformer connects the welding circuit of welding device, the first output of controller controls the on-off of high-frequency inverter circuit by drive circuit one, the second output of controller controls the on-off of the coil circuit of welding device by drive circuit two, coil circuit is used to control the welding device fixed workpiece to be welded, the input of controller is provided with two sampling circuits, one sampling circuit is used to obtain the current and voltage information of welding circuit, another sampling circuit is used to obtain the current and voltage information of coil circuit, realize the on-line identification of defective piece in production process by the algorithm built-in in controller, improve production efficiency.

Description

Technical Field

[0001] This invention relates to the field of metal forming and manufacturing technology, and in particular to a welding stability identification system for impact-welded dissimilar metal wires. Background Technology

[0002] Impact welding of dissimilar metal wires (steel / aluminum) plays a crucial role in the production of electronic components and other fields. Traditional capacitor-powered impact welding offers short welding times and small heat-affected zones, but suffers from poor controllability of capacitor discharge, making precise current regulation impossible. Prolonged use leads to wear and tear, resulting in unstable welding current output. Arc stability is key to the overall stability of the impact welding process. Since arc heat is the primary energy source for melting the workpiece, excessive heat results in weld joints that do not meet requirements, while insufficient heat input prevents effective connection. Therefore, maintaining arc stability ensures stable heat input during welding, which directly determines the final weld quality. Due to the extremely fast process and the generation of a high-temperature arc, online visual inspection is not feasible. Currently, quality inspection of impact welded steel / aluminum dissimilar metal wires relies solely on post-weld manual sorting, limiting inspection methods. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the aforementioned technical problems in the prior art. To this end, embodiments of the present invention provide a welding stability identification system for impact welding of dissimilar metal wires, enabling online identification of defective parts during the production process and improving production efficiency.

[0004] A welding stability identification system for impact welding of dissimilar metal wires according to an embodiment of the present invention includes a power supply, a transformer, a welding device, and a controller. The power supply and the input terminal of the transformer are connected via a high-frequency inverter circuit. The output terminal of the transformer is connected to the welding circuit of the welding device. The first output terminal of the controller controls the on / off state of the high-frequency inverter circuit via a first driving circuit. The second output terminal of the controller controls the on / off state of the coil circuit of the welding device via a second driving circuit. The coil circuit is used to control the welding device to fix the workpiece to be welded. The input terminal of the controller is provided with two sampling circuits. One sampling circuit is used to acquire the current and voltage information of the welding circuit, and the other sampling circuit is used to acquire the current and voltage information of the coil circuit. The welding stability identification algorithm of the controller is as follows:

[0005] S1. Collect the arc-starting current during the arc-starting phase of the welding circuit in at least 10 stable impact welding operations. and arc ignition voltage According to the formula Calculate all the arc-starting heat inputs during each stable impact welding arc-starting phase. The calculated arc-starting heat input Substitute into the formula The average arc-starting heat input for each stage of impact welding is obtained. According to the formula Calculate the standard deviation of the arc initiation stage for each impact welding arc initiation stage. According to the formula Calculate the coefficient of variation of the arc initiation stage for each impact welding arc initiation stage. Let the standard deviation of the arc initiation stage be obtained from multiple stable impact welding arc initiation stages. The average value is the first judgment threshold for the arc initiation stage. Let the coefficient of variation of the arc initiation stage obtained from multiple stable impact welding arc initiation stages be... The average value is the second judgment threshold for the arc-starting phase;

[0006] S2. Collect the arc current during the impact welding arc phase of the welding circuit in at least 10 stable impact welding operations. and arc voltage According to the formula Calculate all arc heat inputs during each stable impact welding arc ignition phase. The calculated arc heat input Substitute into the formula The average arc heat input during each stable impact welding arc phase was obtained. According to the formula Calculate the standard deviation of the arc stage for each stable impact welding arc stage. According to the formula Calculate the arc stage variation coefficient for each stable impact welding arc stage. Let the standard deviation of the arc stage be obtained from multiple stable impact welding arc stages. The average value is the third threshold for the arc-burning stage. Let the coefficient of variation of the arc-burning stage obtained from multiple stable impact welding arc-burning stages be... The average value is the fourth threshold for the arcing stage;

[0007] S3. Using the first and second judgment thresholds obtained in step S1 as judgment indicators, calculate the standard deviation of the arc-starting stage for each subsequent impact welding arc-starting stage. and the coefficient of variation during the arc initiation stage Compare the results with the first and second decision thresholds respectively, such as the standard deviation during the arc initiation stage. The difference from the first judgment threshold is too large or the coefficient of variation during the arc ignition stage is too large. If the difference from the second judgment threshold is too large, it can be determined that the arc ignition stage of the impact welding is unstable.

[0008] S4. Using the third and fourth judgment thresholds obtained in step S2 as judgment indicators, calculate the standard deviation of the arc stage for each subsequent impact welding arc stage. and the coefficient of variation during the arc burning stage Compare with the third and fourth judgment thresholds respectively, such as the standard deviation of the arcing stage. The difference between the value and the third judgment threshold is too large or the coefficient of variation during the arcing stage is too large. If the difference from the fourth judgment threshold is too large, it can be determined that the arc-ignition stage of the impact welding is unstable.

[0009] S5. If either the arc initiation stage or the arc ignition stage of an impact weld is determined to be unstable, then the weld of that impact weld is considered unstable.

[0010] Furthermore, the sampling circuit includes a CN2 Hall sensor, a current sampling circuit, and a voltage sampling circuit. The input terminal of the CN2 Hall sensor is connected to the welding circuit, and the output terminal of the CN2 Hall sensor is connected to the current sampling circuit and the voltage sampling circuit, respectively. The voltage sampling circuit includes a first filter circuit and a first operational amplifier circuit, and the current sampling circuit includes a second filter circuit and a second operational amplifier circuit.

[0011] Furthermore, the first filter circuit includes resistor R7, capacitor C28, resistor R8, and capacitor C29. One end of resistor R7 is connected to the voltage output terminal of the CN2 Hall sensor, and the other end is grounded. One end of capacitor C28 is connected to the voltage output terminal of the CN2 Hall sensor, and the other end is grounded. One end of resistor R8 is connected to the voltage output terminal of the CN2 Hall sensor, and the other end is connected to one end of capacitor C29. The other end of capacitor C29 is grounded.

[0012] Furthermore, the first operational amplifier circuit includes resistor R9, operational amplifier U11A, resistors R10 and R11, variable resistor RP2, capacitor C30, capacitor C31, and resistor R12. One end of resistor R9 is connected to resistor R8, and the other end is connected to the positive input terminal of operational amplifier U11A. One end of resistor R10 is grounded, and the other end is connected to the negative input terminal of operational amplifier U11A. The positive power supply terminal of operational amplifier U11A is connected to the positive terminal of a 15V power supply, and the negative power supply terminal of operational amplifier U11A is connected to the negative terminal of a 15V power supply. R1... One end of resistor R11 is connected to the negative input terminal of the U11A operational amplifier. The other end of resistor R11 is connected to one end of variable resistor RP2. The other end of variable resistor RP2 is connected to the output terminal of the U11A operational amplifier. One end of resistor R12 is connected to the output terminal of the U11A operational amplifier. The other end of resistor R12 is connected to the controller. One end of capacitor C30 is grounded, and the other end is connected to the positive power supply terminal of the U11A operational amplifier. One end of capacitor C31 is grounded, and the other end is connected to the negative power supply terminal of the U11A operational amplifier.

[0013] Furthermore, the second filter circuit includes a resistor R16, a capacitor C34, a resistor R13, and a capacitor C35. One end of the resistor R16 is connected to the current output terminal of the CN2 Hall sensor, and the other end of the resistor R16 is grounded. One end of the capacitor C34 is connected to the current output terminal of the CN2 Hall sensor, and the other end of the capacitor C34 is grounded. One end of the resistor R13 is connected to the current output terminal of the CN2 Hall sensor, and the other end of the resistor R13 is grounded. One end of the capacitor C35 is also grounded.

[0014] Furthermore, the second operational amplifier circuit includes resistor R14, operational amplifier U11B, resistor R15, resistor R17, variable resistor RP5, and resistor R18. One end of resistor R14 is connected to resistor R13, and the other end is connected to the positive input terminal of operational amplifier U11B. One end of resistor R15 is grounded, and the other end is connected to the negative input terminal of operational amplifier U11B. One end of resistor R17 is connected to the negative input terminal of operational amplifier U11B, and the other end is connected to one end of variable resistor RP5. The other end of variable resistor RP5 is connected to the output terminal of operational amplifier U11B. One end of resistor R18 is connected to the output terminal of operational amplifier U11B, and the other end is connected to the controller.

[0015] Furthermore, the sampling circuit connected to the welding circuit converts the voltage obtained from the welding circuit into 0~3.3V and then transmits it to the controller.

[0016] Furthermore, in the arc initiation phase of a single stable impact welding operation, the standard deviation of the arc initiation phase is... The ratio of the first determination threshold to the value is between 0.8 and 1.2, indicating the coefficient of variation during the arc-starting stage. The ratio to the second determination threshold is between 0.8 and 1.2.

[0017] Furthermore, in the arc-ignition phase of a single stable impact welding operation, the standard deviation of the arc-ignition phase is... The ratio of the value to the third judgment threshold is between 0.8 and 1.2, and the coefficient of variation during the arcing stage is... The ratio to the fourth determination threshold is between 0.8 and 1.2.

[0018] Furthermore, the welding device includes a base, a movable clamp, a stationary clamp, an electromagnet, a spring, and a pitch adjustment knob. The stationary clamp is fixed to the base, the movable clamp is slidably disposed on the base, the spring is fixed to the base and one end of the spring is connected to the movable clamp, the electromagnet is located on one side of the spring, and the pitch adjustment knob is located on the other side of the spring. The coil circuit is used to control the electromagnet to generate an attractive force to attract the spring, and the welding circuit is used to provide welding current for welding the workpiece to be welded.

[0019] Based on the above technical solution, the embodiments of the present invention have at least the following beneficial effects: In the above technical solution, the welding process stability detection function is integrated into the impact welding power source, which is more convenient to use compared to adding an additional detection device. Currently, the detection of impact welding only uses monitoring equipment to collect current and voltage signals, merely records the changes in electrical signals during each welding process, and monitors them through upper and lower limits, then uses manual inspection or machine vision to inspect the welding quality of the weldment. The present invention, by collecting welding electrical signals, calculates the real-time average value, standard deviation, and coefficient of variation of the heat input during the welding process, and distinguishes between the arc initiation and arc burning processes, can identify the stage of welding instability, helping engineers quickly locate problems. At the same time, it statistically analyzes the fluctuation range of heat input parameters of qualified samples, and classifies the welding quality according to the values ​​of standard deviation and coefficient of variation. This not only intuitively reflects the stability of the welding process, but also distinguishes the welding quality, making a more in-depth use of the electrical signal information of the welding process, and improving the efficiency of post-weld inspection. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0021] Figure 1 This is a schematic diagram of the welding stability identification system for impact welding dissimilar metal wires according to an embodiment of the present invention;

[0022] Figure 2This is a schematic diagram of the sampling point path in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the welding device in an embodiment of the present invention. Figure 1 ;

[0024] Figure 4 This is a schematic diagram of the welding device in an embodiment of the present invention. Figure 2 ;

[0025] Figure 5 This is a schematic diagram of the welding device in an embodiment of the present invention. Figure 3 ;

[0026] Figure 6 This is a diagram showing the unstable current and voltage changes during the arc ignition stage in an embodiment of the present invention.

[0027] Figure 7 This is a diagram showing the unstable current and voltage changes during the arcing stage in an embodiment of the present invention;

[0028] Figure 8 This is a current and voltage variation diagram showing instability during both the arc ignition and arc burning stages in this embodiment of the invention.

[0029] Figure 9 This is a current and voltage variation diagram showing that is stable during both the arc ignition and arc burning stages in this embodiment of the invention.

[0030] Figure 10 This is a schematic diagram of a finished workpiece to be welded that is unstable during the arc ignition stage, as described in an embodiment of the present invention.

[0031] Figure 11 This is a schematic diagram of a finished workpiece to be welded that is unstable during the arc burning stage, as described in an embodiment of the present invention.

[0032] Figure 12 This is a schematic diagram of a finished workpiece to be welded, where both the arc ignition stage and the arc burning stage are unstable, according to an embodiment of the present invention.

[0033] Figure 13 This is a schematic diagram of a finished workpiece to be welded in an embodiment of the present invention, where both the arc ignition stage and the arc burning stage are stable. Detailed Implementation

[0034] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0035] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0036] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0037] In the description of this invention, unless otherwise explicitly defined, terms such as "setting," "installing," and "connecting" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0038] Currently, most monitoring of impact welding processes only involves tracking changes in welding current and voltage, setting upper and lower limits, without assessing the stability of the welding process. If monitoring equipment used for resistance welding or arc welding is employed, it needs to be adapted to the characteristics of impact welding, leading to more complex maintenance. The overall operating cost is high, requiring dedicated personnel for system management and calibration. The equipment also has significant limitations in its application on the production floor, necessitating the installation of a corresponding communication system.

[0039] like Figure 1 As shown, this invention provides a welding stability identification system for impact welding of dissimilar metal wires, including a power supply, a transformer, a welding device, and a controller. The power supply and the input terminal of the transformer are connected via a high-frequency inverter circuit. The output terminal of the transformer is connected to the welding circuit of the welding device. The first output terminal of the controller controls the on / off state of the high-frequency inverter circuit through a first drive circuit, and the second output terminal of the controller controls the on / off state of the coil circuit of the welding device through a second drive circuit. The coil circuit is used to control the welding device to fix the workpiece to be welded. The input terminal of the controller is equipped with two sampling circuits: one sampling circuit is used to acquire the current and voltage information of the welding circuit, and the other sampling circuit is used to acquire the current and voltage information of the coil circuit.

[0040] Specifically, such as Figures 3 to 5As shown, the welding device includes a base 140, a movable clamp 120, a fixed clamp 130, an electromagnet 110, a spring 150, and a pitch adjustment knob 160. The fixed clamp 130 is fixed to the base 140, the movable clamp 120 is slidably disposed on the base 140, the spring 150 is fixed to the base 140 and one end of the spring 150 is connected to the movable clamp 120, the electromagnet 110 is located on one side of the spring 150, and the pitch adjustment knob 160 is located on the other side of the spring 150. The coil circuit is used to control the electromagnet 110 to generate an attractive force to attract the spring 150, and the welding circuit is used to provide welding current for welding the workpiece to be welded. Furthermore, the spring 150 is rigidly connected to the base 140 via M2 hexagon socket bolts. When the spring 150 is attracted by the electromagnet 110, an arc-starting gap is generated, forming an arc for welding. A pitch adjustment knob 160 is positioned on one side of the spring 150 and aligned with its center. It is fixed to the base 140 with M2 hexagon socket bolts. Rotating the pitch adjustment knob 160 controls the deformation of the spring 150, thus controlling the preload and impact force during welding. The electromagnet 110 is aligned with the center of the other side of the spring 150 and is fixed to the base by a fixing block. When the wire inside the electromagnet 110... When current is applied to the coil circuit, an electromagnetic attraction is generated, causing the spring 150 to move toward the electromagnet 110. When the current is turned off, the spring 150 is no longer bound by the electromagnetic force and springs back toward the pitch adjustment knob 160, causing the workpieces on both sides to impact and combine to form a weld point. The moving clamp 120 is rigidly connected to the mounting hole at the front of the spring 150 via an M2 hexagonal bolt, and the tail end of the spring 150 is rigidly connected to the base 140. The whole structure is a cantilever beam structure, and the clamp gap can be adjusted according to the diameter of the workpiece to be welded, with an adjustment range of 0~2.5mm. The stationary clamp 130 is symmetrically installed with the moving clamp 120 and fixed on the base 140, and the clamp gap is adjustable.

[0041] When using the welding device, the workpieces to be welded are mounted on the static clamps 130 and the moving clamps 120 on the left and right sides, respectively. The static clamp 130 on the right is stationary, while the moving clamp 120 on the left is rigidly connected to the spring 150. One end of the spring 150 is fixed to the base 140. The bending deformation of the spring 150 is adjusted by the pitch adjustment knob 160 on the right side, so that there is a corresponding preload between the moving and static workpieces. The electromagnet 110 is aligned with the radial center line of the left side of the spring 150. During welding, it generates a magnetic attraction force, causing the spring 150 to move the moving workpiece to the left. Under the action of the welding current, the arc is ignited. When the current is turned off, it rebounds, causing the workpieces to be joined together by mechanical impact. By adjusting the pitch adjustment knob 160, the adjustment precision of the spring 150 is higher, and the controllability is better, which is beneficial to improving the stability of the welding process. Applying a shielding gas during the welding process can reduce the influence of oxidizing gases on the welding process, control the generation of oxides, and make the welding process more stable.

[0042] The controller incorporates a digital signal control chip. This chip's PWM drive capability and high-speed ADC sampling accuracy meet actual welding requirements. It should be noted that the welding stability identification algorithm within the digital signal control chip is as follows:

[0043] S1. Collect the arc-starting current during the arc-starting phase of the welding circuit in at least 10 stable impact welding tests. and arc ignition voltage According to the formula Calculate all the arc-starting heat inputs during each stable impact welding arc-starting phase. The calculated arc-starting heat input Substitute into the formula The average arc-starting heat input for each stage of impact welding is obtained. According to the formula Calculate the standard deviation of the arc initiation stage for each impact welding arc initiation stage. According to the formula Calculate the coefficient of variation of the arc initiation stage for each impact welding arc initiation stage. Let the standard deviation of the arc initiation stage be obtained from multiple stable impact welding arc initiation stages. The average value is the first judgment threshold for the arc initiation stage. Let the coefficient of variation of the arc initiation stage obtained from multiple stable impact welding arc initiation stages be... The average value is the second judgment threshold for the arc-starting phase;

[0044] S2. Collect the arc current during the arc ignition phase of the welding circuit in at least 10 stable impact welding tests. and arc voltage According to the formula Calculate all arc heat inputs during each stable impact welding arc ignition phase. The calculated arc heat input Substitute into the formula The average arc heat input during each stable impact welding arc phase was obtained. According to the formula Calculate the standard deviation of the arc stage for each stable impact welding arc stage. According to the formula Calculate the arc stage variation coefficient for each stable impact welding arc stage. Let the standard deviation of the arc stage be obtained from multiple stable impact welding arc stages. The average value is the third threshold for the arc-burning stage. Let the coefficient of variation of the arc-burning stage obtained from multiple stable impact welding arc-burning stages be... The average value is the fourth threshold for the arcing stage;

[0045] S3. Using the first and second judgment thresholds obtained in step S1 as judgment indicators, calculate the standard deviation of the arc-starting stage for each subsequent impact welding arc-starting stage. and the coefficient of variation during the arc initiation stage Compare the results with the first and second decision thresholds respectively, such as the standard deviation during the arc initiation stage. The difference from the first judgment threshold is too large or the coefficient of variation during the arc ignition stage is too large. If the difference from the second judgment threshold is too large, it can be determined that the arc ignition stage of the impact welding is unstable.

[0046] S4. Using the third and fourth judgment thresholds obtained in step S2 as judgment indicators, calculate the standard deviation of the arc stage for each subsequent impact welding arc stage. and the coefficient of variation during the arc burning stage Compare with the third and fourth judgment thresholds respectively, such as the standard deviation of the arcing stage. The difference between the value and the third judgment threshold is too large or the coefficient of variation during the arcing stage is too large. If the difference from the fourth judgment threshold is too large, it can be determined that the arc-ignition stage of the impact welding is unstable.

[0047] S5. If either the arc initiation phase or the arc burning phase of a single impact weld is deemed unstable, then the weld is considered unstable. In a stable impact weld, the standard deviation of the arc initiation phase is... The ratio of the first judgment threshold to the coefficient of variation during the arc-starting stage should be between 0.8 and 1.2. The ratio to the second judgment threshold should be between 0.8 and 1.2; during the arc-ignition phase of a single stable impact weld, the standard deviation of the arc-ignition phase... The ratio of the third judgment threshold to the value is between 0.8 and 1.2, and the coefficient of variation during the arcing stage is... The ratio to the fourth judgment threshold is between 0.8 and 1.2.

[0048] like Figure 2 As shown, the sampling circuit includes a CN2 Hall sensor, a current sampling circuit, and a voltage sampling circuit. The input terminal of the CN2 Hall sensor is connected to the welding circuit, and the output terminal of the CN2 Hall sensor is connected to the current sampling circuit and the voltage sampling circuit, respectively. The voltage sampling circuit includes a first filter circuit and a first operational amplifier circuit, and the current sampling circuit includes a second filter circuit and a second operational amplifier circuit.

[0049] Specifically, the first filter circuit includes resistor R7, capacitor C28, resistor R8, and capacitor C29. One end of resistor R7 is connected to the voltage output terminal of the CN2 Hall sensor, and the other end is grounded. One end of capacitor C28 is connected to the voltage output terminal of the CN2 Hall sensor, and the other end is grounded. One end of resistor R8 is connected to the voltage output terminal of the CN2 Hall sensor, and the other end is connected to one end of capacitor C29, with the other end of capacitor C29 grounded. The first operational amplifier circuit includes resistor R9, operational amplifier U11A, resistors R10 and R11, variable resistor RP2, capacitors C30 and C31, and resistor R12. One end of resistor R9 is connected to resistor R8, and the other end is connected to the positive input terminal of operational amplifier U11A. One end of resistor R10 is grounded, and the other end is connected to the negative input terminal of operational amplifier U11A. The positive power supply terminal of operational amplifier U11A is connected to the positive terminal of a 15V power supply, and the negative power supply terminal of operational amplifier U11A is connected to the negative terminal of a 15V power supply. One end of resistor R11 is connected to the negative input terminal of operational amplifier U11A. The other end of resistor R11 is connected to one end of variable resistor RP2. The other end of variable resistor RP2 is connected to the output terminal of operational amplifier U11A. One end of resistor R12 is connected to the output terminal of operational amplifier U11A. The other end of resistor R12 is connected to the controller. One end of capacitor C30 is grounded and the other end is connected to the positive power supply terminal of operational amplifier U11A. One end of capacitor C31 is grounded and the other end is connected to the negative power supply terminal of operational amplifier U11A.

[0050] Specifically, the second filter circuit includes resistor R16, capacitor C34, resistor R13, and capacitor C35. One end of resistor R16 is connected to the current output terminal of the CN2 Hall sensor, and the other end of resistor R16 is grounded. One end of capacitor C34 is connected to the current output terminal of the CN2 Hall sensor, and the other end of capacitor C34 is grounded. One end of resistor R13 is connected to the current output terminal of the CN2 Hall sensor, and the other end of resistor R13 is grounded. One end of capacitor C35 is also grounded. The second operational amplifier circuit includes resistor R14, operational amplifier U11B, resistors R15 and R17, variable resistor RP5, and resistor R18. One end of resistor R14 is connected to resistor R13, and the other end is connected to the positive input terminal of operational amplifier U11B. One end of resistor R15 is grounded, and the other end is connected to the negative input terminal of operational amplifier U11B. One end of resistor R17 is connected to the negative input terminal of operational amplifier U11B, and the other end is connected to one end of variable resistor RP5. The other end of variable resistor RP5 is connected to the output terminal of operational amplifier U11B. One end of resistor R18 is connected to the output terminal of operational amplifier U11B, and the other end is connected to the controller.

[0051] The sampling circuit connected to the welding circuit converts the voltage obtained from the welding circuit into a 0-3.3V range before transmitting it to the controller. Specifically, the welding voltage is acquired from both ends of the moving clamp 120 and the stationary clamp 130 of the welding device using a twisted pair cable. The Hall sensor CN2 detects the voltage value of the welding circuit and inputs it to the sampling circuit. After filtering by capacitors and other components in the first filter circuit of the sampling circuit, the input value is converted into a 0-3.3V voltage value by the operational amplifier U11A and then sent to the digital signal control chip for data processing. The welding current is acquired from the welding circuit using the Hall sensor CN2. After rectification by the second filter circuit and the second operational amplifier circuit, the current is transmitted to the digital signal control chip for data processing. Hardware DSP technology is used for accelerated calculation to achieve the function of quickly processing large amounts of data. Based on the real-time current and voltage output, the power of the arc heat input is calculated by integration, and the corresponding standard deviation and coefficient of variation are calculated using statistical principles. By monitoring the fluctuation range of the standard deviation and coefficient of variation in real time, the stability of the welding can be judged.

[0052] In this embodiment, the welding stability process of impact welding dissimilar metal wires is as follows: The +3.3V voltage signal output from the PWM1 output terminal of the digital signal control chip is converted into a +24V voltage by the first drive circuit. This voltage is then converted by a transformer to obtain the 12V voltage signal required to drive the MOSFET in the high-frequency inverter circuit, thereby controlling the rapid switching on and off of the MOSFET in the welding current main circuit and regulating the current output of the welding current main circuit. The +3.3V voltage signal output from the PWM2 output terminal is converted into a +16.5V or -7.5V pulse signal by the second drive circuit, used to control the switching of the MOSFET in the coil circuit, achieving the purpose of controlling the coil current output, and thus controlling the attraction force of the electromagnet 110. The feedback signal input from the sampling circuit of the welding current and the coil circuit current is connected to the digital signal control chip, which is connected to the high-speed AD module of the digital signal control chip. This module converts the analog signal into a digital signal, monitors the current change during the welding process, and performs PID calculations to regulate the PWM output duty cycle, achieving closed-loop control.

[0053] It should be noted that the impact welding process is divided into four stages: short-circuit contact, arc ignition, arc combustion, and impact bonding. The electric arc plays a major role in the arc ignition and combustion stages. It is easy to see that the arc voltage and arc length are linearly related, while the welding current affects the electric field strength, thus controlling the arc's intensity. Therefore, the stability of the arc can be analyzed from the product of the welding voltage and current signals—the change in heat input power. When the arc burns stably, the heat input remains within a certain range; when there is significant arc drift or spatter, the current and voltage fluctuate greatly, leading to poor weld formation and affecting the joint quality. Therefore, this chapter will use the welding process heat input as a characterizing parameter, selecting each parameter as a sample to study the intrinsic relationship between the standard deviation and coefficient of variation of the welding heat input and arc stability. The standard deviation reflects the fluctuation range of the instantaneous sample value around the sample mean, reflecting the dispersion of the sample values. The larger the standard deviation, the more unstable the process. The coefficient of variation (the quotient of the standard deviation and the mean) represents the magnitude of the sample value's variation range relative to its mean. The larger the coefficient of variation, the worse the sample's stability. Therefore, the stability of the impact welding process can be assessed by comparing the values ​​of the standard deviation of welding heat input and the coefficient of variation.

[0054] Using the heat input calculated from the voltage and current during the arc initiation and arc ignition stages of the welding process as samples, the standard deviation and coefficient of variation were calculated. The statistical data were then analyzed and combined with the electrical signals and heat input probability distribution during the welding process to determine the stability of the welding heat input, thereby identifying the state of the arc. Based on the impact welding process, it is known that the arc acts during the arc initiation and arc ignition stages. The changes in heat input data during these two stages were analyzed, and the average value, standard deviation, and coefficient of variation of the heat input during the arc initiation and arc ignition stages of impact welding were calculated respectively.

[0055] like Figure 6 As shown in the figure, the upper curve represents the voltage change line, and the lower curve represents the current change line. When the welding current is 75A, an abnormal short circuit occurs during the arc ignition process, causing a surge in current and a sharp drop in voltage. This results in severe arc attenuation and significant changes in the arc. Therefore, the final workpiece image is as follows. Figure 10 As shown, it is unqualified.

[0056] like Figure 7 As shown, the welding process is stable during the arc ignition stage, but becomes unstable during the arc burning stage. The current suddenly surges, and the welding voltage drops sharply. Due to the triggering of the current limiting protection, the welding process is subsequently interrupted, and both the current and voltage outputs are shut off. The resulting finished workpiece is shown in the image below. Figure 11 As shown, it is also unqualified.

[0057] like Figure 8 As shown, when both the arc ignition and arc combustion stages are unstable, significant current and voltage fluctuations occur during both the arc ignition and stable arc combustion stages of the welding process, leading to marked instability in the welding process. The final workpiece image is shown below. Figure 12 As shown, it is unqualified.

[0058] Among them, such as Figure 9 When the welding process is relatively stable, the current and voltage waveforms are shown, and the resulting final workpiece image is as follows. Figure 13 As shown, it is qualified, and the weld is very smooth and uniform.

[0059] right Figures 6 to 9 The stability of the arc initiation phase was calculated and obtained as shown in Table 1 below:

[0060]

[0061] right Figures 6 to 9 The stability during the arcing stage was calculated and obtained as shown in Table 2 below:

[0062]

[0063] By collecting and comparing the calculated values ​​during the arc initiation phase, it can be seen that... Figure 6 During the arc initiation phase, significant instability is observed, with a large standard deviation and coefficient of variation. Figure 7 During the arc ignition phase, the current and voltage waveforms are relatively stable, resulting in smaller standard deviations and coefficients of variation. Figure 8 In the process, the arc-starting process also showed significant instability, with both its standard deviation and coefficient of variation being relatively large. Figure 9 During the arc ignition phase, the current and voltage waveforms are stable, resulting in relatively small standard deviations and coefficients of variation.

[0064] By collecting and comparing the calculated values ​​during the arc-burning stage, it can be seen that... Figure 6 During the arcing phase, the current and voltage waveforms are relatively stable, resulting in smaller standard deviations and coefficients of variation. Figure 7 During the arc-ignition stage, significant instability is observed, with large standard deviations and coefficients of variation during the arc-ignition stage. Figure 8 During the arc-ignition stage, significant instability is observed, with large standard deviations and coefficients of variation during the arc-ignition stage. Figure 9 During the arcing stage, the current and voltage waveforms are relatively stable, resulting in smaller standard deviations and coefficients of variation.

[0065] The actual welding effect is as follows Figure 13 As shown, when the welding process is unstable, the differences in weld formation are quite obvious. Figure 10 , Figure 11 , Figure 12 Due to the instability of the welding process, the weld formation quality is poor; Figure 13The welding process is stable, and the weld formation quality is good. By inputting the standard deviation and coefficient of variation of the heat input for the corresponding welding process into the monitoring program, and through real-time calculation and comparison, the stability of arc ignition or arc burning during the welding process can be identified. Furthermore, based on the fluctuation range of the standard deviation and coefficient of variation, the welding quality can be inferred, and unqualified weldments can be rejected, which can further improve the yield rate of the welding process.

[0066] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A welding stability identification system for impact welding of dissimilar metal wires, characterized in that: The system includes a power supply, a transformer, a welding device, and a controller. The power supply and the input terminal of the transformer are connected via a high-frequency inverter circuit. The output terminal of the transformer is connected to the welding circuit of the welding device. The first output terminal of the controller controls the on / off state of the high-frequency inverter circuit via a first drive circuit, and the second output terminal of the controller controls the on / off state of the coil circuit of the welding device via a second drive circuit. The coil circuit is used to control the welding device to fix the workpiece to be welded. The input terminal of the controller is equipped with two sampling circuits: one sampling circuit is used to acquire the current and voltage information of the welding circuit, and the other sampling circuit is used to acquire the current and voltage information of the coil circuit. The welding stability identification algorithm of the controller is as follows: S1. Collect the arc-starting current during the arc-starting phase of the welding circuit in at least 10 stable impact welding operations. and arc ignition voltage According to the formula Calculate all the arc-starting heat inputs during each stable impact welding arc-starting phase. The calculated arc-starting heat input Substitute into the formula The average arc-starting heat input for each stage of impact welding is obtained. According to the formula Calculate the standard deviation of the arc initiation stage for each impact welding arc initiation stage. According to the formula Calculate the coefficient of variation of the arc initiation stage for each impact welding arc initiation stage. Let the standard deviation of the arc initiation stage be obtained from multiple stable impact welding arc initiation stages. The average value is the first judgment threshold for the arc initiation stage. Let the coefficient of variation of the arc initiation stage obtained from multiple stable impact welding arc initiation stages be... The average value is the second judgment threshold for the arc-starting phase; S2. Collect the arc current during the impact welding arc phase of the welding circuit in at least 10 stable impact welding operations. and arc voltage According to the formula Calculate all arc heat inputs during each stable impact welding arc ignition phase. The calculated arc heat input Substitute into the formula The average arc heat input during each stable impact welding arc phase was obtained. According to the formula Calculate the standard deviation of the arc stage for each stable impact welding arc stage. According to the formula Calculate the arc stage variation coefficient for each stable impact welding arc stage. Let the standard deviation of the arc stage be obtained from multiple stable impact welding arc stages. The average value is the third threshold for the arc-burning stage. Let the coefficient of variation of the arc-burning stage obtained from multiple stable impact welding arc-burning stages be... The average value is the fourth threshold for the arcing stage; S3. Using the first and second judgment thresholds obtained in step S1 as judgment indicators, calculate the standard deviation of the arc-starting stage for each subsequent impact welding arc-starting stage. and the coefficient of variation during the arc initiation stage Compare the results with the first and second decision thresholds respectively, such as the standard deviation during the arc initiation stage. The difference from the first judgment threshold is too large or the coefficient of variation during the arc ignition stage is too large. If the difference from the second judgment threshold is too large, it can be determined that the arc ignition stage of the impact welding is unstable. S4. Using the third and fourth judgment thresholds obtained in step S2 as judgment indicators, calculate the standard deviation of the arc stage for each subsequent impact welding arc stage. and the coefficient of variation during the arc burning stage Compare with the third and fourth judgment thresholds respectively, such as the standard deviation of the arcing stage. The difference between the value and the third judgment threshold is too large or the coefficient of variation during the arcing stage is too large. If the difference from the fourth judgment threshold is too large, it can be determined that the arc-ignition stage of the impact welding is unstable. S5. If either the arc initiation stage or the arc ignition stage of an impact weld is determined to be unstable, then the weld of that impact weld is considered unstable.

2. The welding stability identification system for impact welding dissimilar metal wires according to claim 1, characterized in that: The sampling circuit includes a CN2 Hall sensor, a current sampling circuit, and a voltage sampling circuit. The input terminal of the CN2 Hall sensor is connected to the welding circuit, and the output terminal of the CN2 Hall sensor is connected to both the current sampling circuit and the voltage sampling circuit. The voltage sampling circuit includes a first filter circuit and a first operational amplifier circuit, and the current sampling circuit includes a second filter circuit and a second operational amplifier circuit.

3. The welding stability identification system for impact welding dissimilar metal wires according to claim 2, characterized in that: The first filter circuit includes resistor R7, capacitor C28, resistor R8, and capacitor C29. One end of resistor R7 is connected to the voltage output terminal of the CN2 Hall sensor, and the other end is grounded. One end of capacitor C28 is connected to the voltage output terminal of the CN2 Hall sensor, and the other end is grounded. One end of resistor R8 is connected to the voltage output terminal of the CN2 Hall sensor, and the other end is connected to one end of capacitor C29. The other end of capacitor C29 is grounded.

4. The welding stability identification system for impact welding dissimilar metal wires according to claim 3, characterized in that: The first operational amplifier circuit includes resistor R9, operational amplifier U11A, resistors R10 and R11, variable resistor RP2, capacitor C30, capacitor C31, and resistor R12. One end of resistor R9 is connected to resistor R8, and the other end is connected to the positive input terminal of operational amplifier U11A. One end of resistor R10 is grounded, and the other end is connected to the negative input terminal of operational amplifier U11A. The positive power supply terminal of operational amplifier U11A is connected to the positive terminal of a 15V power supply, and the negative power supply terminal of operational amplifier U11A is connected to the negative terminal of a 15V power supply. Resistor R11... One end of resistor R11 is connected to the negative input terminal of the U11A operational amplifier. The other end of resistor R11 is connected to one end of variable resistor RP2. The other end of variable resistor RP2 is connected to the output terminal of the U11A operational amplifier. One end of resistor R12 is connected to the output terminal of the U11A operational amplifier. The other end of resistor R12 is connected to the controller. One end of capacitor C30 is grounded, and the other end is connected to the positive power supply terminal of the U11A operational amplifier. One end of capacitor C31 is grounded, and the other end is connected to the negative power supply terminal of the U11A operational amplifier.

5. The welding stability identification system for impact welding dissimilar metal wires according to claim 2, characterized in that: The second filter circuit includes a resistor R16, a capacitor C34, a resistor R13, and a capacitor C35. One end of the resistor R16 is connected to the current output terminal of the CN2 Hall sensor, and the other end of the resistor R16 is grounded. One end of the capacitor C34 is connected to the current output terminal of the CN2 Hall sensor, and the other end of the capacitor C34 is grounded. One end of the resistor R13 is connected to the current output terminal of the CN2 Hall sensor, and the other end of the resistor R13 is grounded. One end of the capacitor C35 is also grounded.

6. The welding stability identification system for impact welding dissimilar metal wires according to claim 5, characterized in that: The second operational amplifier circuit includes resistor R14, operational amplifier U11B, resistors R15 and R17, variable resistor RP5, and resistor R18. One end of resistor R14 is connected to resistor R13, and the other end is connected to the positive input terminal of operational amplifier U11B. One end of resistor R15 is grounded, and the other end is connected to the negative input terminal of operational amplifier U11B. One end of resistor R17 is connected to the negative input terminal of operational amplifier U11B, and the other end is connected to one end of variable resistor RP5. The other end of variable resistor RP5 is connected to the output terminal of operational amplifier U11B. One end of resistor R18 is connected to the output terminal of operational amplifier U11B, and the other end is connected to the controller.

7. The welding stability identification system for impact welding dissimilar metal wires according to claim 1, characterized in that: The sampling circuit connected to the welding circuit converts the voltage obtained from the welding circuit into 0~3.3V and then transmits it to the controller.

8. The welding stability identification system for impact welding dissimilar metal wires according to claim 1, characterized in that: The standard deviation of the arc initiation phase in a single stable impact welding operation. The ratio of the first determination threshold to the value is between 0.8 and 1.2, indicating the coefficient of variation during the arc-starting stage. The ratio to the second determination threshold is between 0.8 and 1.

2.

9. The welding stability identification system for impact welding dissimilar metal wires according to claim 1, characterized in that: Standard deviation of the arc phase during a single stable impact welding operation The ratio of the value to the third judgment threshold is between 0.8 and 1.2, and the coefficient of variation during the arcing stage is... The ratio to the fourth determination threshold is between 0.8 and 1.

2.

10. The welding stability identification system for impact-welded dissimilar metal wires according to claim 1, characterized in that: The welding device includes a base (140), a movable clamp (120), a stationary clamp (130), an electromagnet (110), a spring (150), and a pitch adjustment knob (160). The stationary clamp (130) is fixed to the base (140), the movable clamp (120) is slidably disposed on the base (140), the spring (150) is fixed to the base (140), and one end of the spring (150) is connected to the movable clamp (120). The electromagnet (110) is located on one side of the spring (150), and the pitch adjustment knob (160) is located on the other side of the spring (150). The coil circuit is used to control the electromagnet (110) to generate an attractive force to attract the spring (150), and the welding circuit is used to provide welding current for welding the workpiece to be welded.

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