Gas metal arc welding equipment

Abstract

The utility model discloses gas metal arc welding equipment which comprises a welding gun, a welding power supply and a shielding gas device, the welding power supply and the shielding gas device are respectively connected with the welding gun, the welding gun is connected with a wire disc through a servo wire feeder, and the welding power supply comprises a main power supply and an auxiliary power supply. The double-power-supply structure of the auxiliary power supply and the main power supply is adopted, the auxiliary power supply is used for outputting arc striking current, small and stable electric arcs are formed in cooperation with wire drawing separation of the servo wire feeder after a welding wire makes contact with a welding product, the effects that arcing is stable, the welding wire is not molten or does not explode after being molten can be achieved, arc breaking is avoided, the arc striking success rate is high, and the service life is long. And after the electric arc is stable, the main power supply outputs the welding current to carry out normal set welding, so that the welding arc-starting splashing in a conventional large current impact arc-starting mode can be effectively avoided, the arc-starting success rate is improved, and the welding quality is improved.

Description

A gas metal arc welding device Technical Field

[0001] This utility model relates to a welding device, specifically a gas metal arc welding device. Background Technology

[0002] With the development of industrial production and the advancement of technology, welding technology is being used more and more widely in the manufacturing industry. Among them, gas metal arc welding (GMAW), as a highly efficient welding method, is characterized by its fast welding speed and good welding quality, and is widely used in the welding of various metal materials. In practical applications, the arc initiation process of GMAW has received widespread attention, and various industries have placed higher demands on the success rate of arc initiation, welding spatter, and welding quality during the GMAW process.

[0003] Current gas shielded welding power supplies are all single-power-output, mostly using a high-current impulse arc ignition method. The arc ignition process primarily involves feeding the consumable electrode wire at a certain speed. During arc ignition, a large current is output, and when the wire contacts the workpiece, it instantly short-circuits and melts, creating a gap between the wire and the workpiece. The resulting spatial ionization generates an arc. Especially in large-diameter, thick-wire gas shielded welding, the PWM circuit is fully activated during arc ignition, outputting the maximum welding current to ensure the wire melts instantly and burns a sufficient discharge distance to form an arc. However, this method has significant drawbacks:

[0004] First, the conduction of current is uncontrollable when the welding wire contacts the base material during feeding. Uncertain factors such as the oxide film on the product surface often cause the welding wire to stick to the base material, affecting the generation of the arc space and leading to arc failure. As a result, the success rate of arc ignition cannot be determined.

[0005] Secondly, when performing gas shielded welding of large-diameter coarse wire, the power of the welding power source is very large, mostly around 1000A. If the arc ignition current is too small, the distance of melting the welding wire is short, the discharge distance is insufficient, and a stable arc cannot be formed, resulting in arc ignition failure. If a power source with an output of 1000A can simultaneously achieve a stable output of 30A, the circuit design is extremely difficult, and the implementation is both difficult and costly.

[0006] Third, if the arc-starting current is too large, the welding wire and the workpiece are prone to sticking together during a short circuit; if the current is too large, the short circuit melting will be violent, resulting in large spatter and directly affecting the welding quality.

[0007] Therefore, this patent aims to provide a gas metal arc welding device and arc initiation method with a high arc initiation success rate and minimal arc spatter. Summary of the Invention

[0008] The purpose of this invention is to provide a gas metal arc welding (GMAW) device to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, this utility model provides the following technical solution:

[0010] A gas metal arc welding (GMAW) apparatus includes a welding torch and a welding power source and a shielding gas device respectively connected to the welding torch. The welding torch is connected to a wire spool via a servo wire feeder. The welding power source includes a main power source and an auxiliary power source. The product to be welded is placed at the end of the welding torch.

[0011] Furthermore, the welding power supply is equipped with an arc control circuit, which includes an arc switch, a filter circuit, a PI adjustment circuit, and a PWM conversion circuit.

[0012] Furthermore, one end of the arc switch is connected to the gate (G) terminal of the MOSFET M1. The filter circuit includes a sliding resistor WE1, a first resistor R1, and a first capacitor C1. The output of the filter circuit is connected to the non-inverting input terminal (interface 3) of the operational amplifier U2 in the operational amplifier circuit. The inverting input terminal (interface 2) of the operational amplifier U2 is connected to the current feedback terminal J1's interface 3 via a sixth resistor R6. The PI adjustment circuit includes a fifth resistor R5, a seventh resistor R7, and a second capacitor C2. The fifth resistor R5 is connected in parallel with the operational amplifier... The inverting input and output terminals of U2 are connected in series with the seventh resistor R7 and the second capacitor C2, and then in parallel with the inverting input and output terminals of the operational amplifier U2. The output terminal of the operational amplifier U2 is also connected to the 3rd interface of the conversion chip U1 in the PWM conversion circuit through the second resistor R2. The 6th interface of the conversion chip U1 is connected to the source of MOSFET M1 and the 2nd interface of chip G1 through the third resistor R3. The 5th interface of the conversion chip U1 and the drain of MOSFET M1 are grounded. The 2nd interface of chip G1 is grounded through the fourth resistor R4.

[0013] Furthermore, the arc control circuit is equipped with arc voltage V1 and arc current A1 for feedback and acquisition.

[0014] Furthermore, the arc control circuit is equipped with feedback and acquisition of the main arc voltage V2 and the main arc current A2.

[0015] Compared with existing technologies, the beneficial effects of this utility model are:

[0016] This invention employs a dual-power supply structure consisting of an auxiliary power supply and a main power supply. The auxiliary power supply outputs an arc-ignition current, which, in conjunction with a servo wire feeder, separates the welding wire after it comes into contact with the welded product, forming a small and stable arc. This ensures stable arc ignition without melting or cracking the welding wire, preventing arc breakage and achieving a high arc ignition success rate. Once the arc is stable, the main power supply outputs the welding current for normal welding. This effectively avoids arc spatter caused by conventional high-current impact arc ignition methods, improving the arc ignition success rate and welding quality. Attached Figure Description

[0017] Figure 1 is a schematic diagram of the structure of this utility model;

[0018] Figure 2 is a circuit diagram of the arc control circuit in this utility model;

[0019] Figure 3 is a signal schematic diagram of this utility model;

[0020] In the diagram: 1-Welding power source; 2-Welding torch; 3-Shielding gas device; 4-Servo wire feeder; 5-Wire spool; 6-Main power supply; 7-Auxiliary power supply; 8-Product to be welded. Detailed Implementation

[0021] The technical solution of this patent will be further described in detail below with reference to specific embodiments.

[0022] Please refer to Figures 1-3. A gas metal arc welding (GMAW) apparatus includes a welding torch 2 and a welding power source 1 and a shielding gas device 3, both connected to the welding torch 2. The welding torch 2 is connected to a wire spool 5 via a servo wire feeder 4, which can precisely control the wire feeding and drawing speeds and distances. The welding power source 1 includes a main power source 6 and an auxiliary power source 7. The product to be welded 8 is placed at the end of the welding torch 2. An independent, high-precision, low-current auxiliary power source 7 is used as the arc-ignition power source. For welding wires with a diameter of 5mm or less, an arc-ignition current of less than 30A is sufficient.

[0023] The welding power supply 1 is equipped with an arc control circuit, which includes an arc switch, a filter circuit, a PI adjustment circuit, and a PWM conversion circuit. One end of the arc switch is connected to the gate (G) terminal of MOSFET M1. The filter circuit includes a sliding resistor WE1, a first resistor R1, and a first capacitor C1. The output of the filter circuit is connected to the non-inverting input terminal (interface 3) of operational amplifier U2 in the operational amplifier circuit. The inverting input terminal (interface 2) of operational amplifier U2 is connected to the interface 3 of current feedback terminal J1 through a sixth resistor R6. The PI adjustment circuit includes a fifth resistor R5, a seventh resistor R7, and a second capacitor C2. The fifth resistor R5 is connected in parallel between the inverting input terminal and the output terminal of operational amplifier U2. The seventh resistor R7 and the second capacitor C2 are connected in series and then in parallel between the inverting input terminal and the output terminal of operational amplifier U2. The output terminal of operational amplifier U2 is also connected to the interface 3 of conversion chip U1 in the PWM conversion circuit through a second resistor R2. The interface 6 of conversion chip U1 is connected to the source (S) terminal of MOSFET M1 and the interface 2 of chip G1 through a third resistor R3. The interface 5 of conversion chip U1 and the drain (D) terminal of MOSFET M1 are both grounded. The interface 2 of chip G1 is grounded through a fourth resistor R4. The arc-maintaining control circuit is equipped with feedback and acquisition of arc-maintaining voltage V1 and arc-maintaining current A1. The main arc voltage V2 and main arc current A2 are also fed back and acquired. This arc-maintaining control circuit can output a 50kHz PWM waveform. The circuit structure is simple, with a 300µs PI dynamic response speed. When the wire feeding distance of the servo wire feeder 4 exceeds the set distance, and no relevant signal is detected or the relevant value is reached, the arc can be re-ignited. Multiple repeated wire feedings and current contact discharges can effectively break down the oxide film on the product. If the number of repeated arc ignitions exceeds the protection value, the circuit enters an over-limit protection state.

[0024] The arc ignition method of the gas metal arc welding equipment adopts a dual power supply structure of auxiliary power supply 7 and main power supply 6. The servo wire feeder 4 feeds the wire into contact with the welding product. The auxiliary power supply 7 outputs the arc ignition current, which is ≤30A. If the welding wire is pulled back, the arc ignition voltage breaks down the ionized gas, conducts and forms a stable arc. When the voltage and current reach the preset values, the arc ignition is successful. After successful arc ignition, the main power supply 6 outputs the welding current according to the program instructions to perform welding. If the welding wire is pulled back, the current and voltage values ​​are detected and do not reach the set values. Therefore, the arc ignition is unsuccessful. The servo wire feeder 4 performs a second arc ignition action of feeding and pulling the wire again, thereby ensuring the success rate of arc ignition.

[0025] This invention employs a dual-power supply structure consisting of an auxiliary power supply 7 and a main power supply 6. The auxiliary power supply 7 outputs a smaller current, which, in conjunction with the wire drawing action, ionizes the gas to form a small electric arc, thus igniting the arc. This small electric arc is not used to melt the welding wire; it simply serves to conduct the circuit, forming the arc and acting as a guide to assist the subsequent output of the larger welding current from the main power supply 6. Furthermore, the welding current is output according to the controlled waveform rhythm and is directly used to melt the welding wire, thereby avoiding the detonation, shattering, and spattering caused by high-current contact.

[0026] The above-described embodiments of the present invention do not constitute a limitation on the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A gas shielded welding apparatus comprising a welding torch (2) and a welding power source (1) and a shielding gas device (3) connected to the welding torch (2) respectively, characterized in that, The welding torch (2) is connected to a wire spool (5) via a servo wire feeder (4). The welding power source (1) includes a main power source (6) and an auxiliary power source (7). The product to be welded (8) is placed at the end of the welding torch (2).

2. The gas tungsten arc welding apparatus of claim 1, wherein, The welding power supply (1) is equipped with an arc control circuit, which includes an arc switch, a filter circuit, a PI adjustment circuit, and a PWM conversion circuit.

3. The gas tungsten arc welding apparatus of claim 2, wherein, One end of the arc switch is connected to the gate (G) terminal of MOSFET M1. The filter circuit includes a sliding resistor WE1, a first resistor R1, and a first capacitor C1. The output of the filter circuit is connected to the non-inverting input terminal (interface 3) of operational amplifier U2 in the operational amplifier circuit. The inverting input terminal (interface 2) of operational amplifier U2 is connected to the interface 3 of current feedback terminal J1 through a sixth resistor R6. The PI adjustment circuit includes a fifth resistor R5, a seventh resistor R7, and a second capacitor C2. The fifth resistor R5 is connected in parallel between the inverting input terminal and the output terminal of operational amplifier U2. The seventh resistor R7 and the second capacitor C2 are connected in series and then in parallel between the inverting input terminal and the output terminal of operational amplifier U2. The output terminal of operational amplifier U2 is also connected to the interface 3 of conversion chip U1 in the PWM conversion circuit through a second resistor R2. The interface 6 of conversion chip U1 is connected to the source (S) terminal of MOSFET M1 and the interface 2 of chip G1 through a third resistor R3. The interface 5 of conversion chip U1 and the drain (D) terminal of MOSFET M1 are both grounded. The interface 2 of chip G1 is grounded through a fourth resistor R4.

4. The gas metal arc welding equipment according to claim 2 or 3, characterized in that, The arc control circuit is equipped with feedback and acquisition of arc voltage V1 and arc current A1.

5. The gas metal arc welding equipment according to claim 2 or 3, characterized in that, The arc control circuit is equipped with feedback and acquisition of the main arc voltage V2 and the main arc current A2.

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