A fast-frequency TIG arc material addition system and material addition method

Abstract

The present invention provides a fast-frequency TIG arc additive system and additive method; wherein the additive system includes a fast-frequency pulse current main circuit, a base current main circuit, a control circuit, and a high-frequency high-voltage arc ignition circuit; the input ends of the fast-frequency pulse current main circuit and the base current main circuit are respectively connected to an external power supply through a rectifier filter circuit; the output end of the fast-frequency pulse current main circuit is connected to a welding load through a relay; the output end of the base current main circuit is connected to the welding load, and the negative pole of the output end of the base current main circuit is connected to a coupling inductor; the coupling inductor is also connected to the high-frequency high-voltage arc ignition circuit to couple the high-frequency high-voltage arc ignition circuit with the negative pole of the output end of the base current main circuit. The additive system disconnects the fast-frequency pulse main circuit before arc ignition is successfully started, preventing the arc-starting high-frequency high-voltage electricity from being introduced into the fast-frequency pulse main circuit, protecting the main circuit electronic components from being damaged by the high-frequency high-voltage electricity, and ensuring arc ignition stability.

Description

Technical Field

[0001] The present invention relates to the field of arc material addition technology, and more particularly to a fast-frequency TIG arc material addition system and a material addition method. Background Art

[0002] In recent years, arc additive manufacturing has become a research focus in the additive manufacturing field. Traditional TIG arc additive manufacturing (TIG) involves high heat input and a poorly concentrated arc, resulting in grain coarsening and reduced mechanical properties in the resulting parts. The fast-frequency pulsed TIG process constricts the arc, improving arc energy density and stiffness, enhancing weld pool stirring, and refining weld grains and improving weld mechanical properties. Arc additive manufacturing is developing towards integrated, high-precision control.

[0003] The welding power supply of the existing fast-frequency pulse TIG arc additive system includes a fast-frequency pulse current main circuit, a base current main circuit and a control circuit, such as Figure 1 As shown in the figure. During the arc-starting phase, the high-frequency, high-voltage arc-starting electricity is output in parallel by the fast-frequency pulse current main circuit and the base current main circuit, breaking down the air between the workpiece and the tungsten electrode to achieve arc starting. However, the high-frequency, high-voltage arc-starting electricity will return to the positive terminal of the base current main circuit through components such as capacitor C2, resistor R2, resistor R1 / capacitor C1 of the fast-frequency pulse current main circuit, making the voltage between the workpiece and the tungsten electrode insufficient to break down the air, resulting in unsuccessful arc starting. At the same time, the high-frequency, high-voltage arc-starting electricity needs to be as high as 3000V, which is much higher than the withstand voltage of the IGBT switches Q1 and Q2 of 650V. Therefore, the high-frequency, high-voltage arc-starting electricity passing through the IGBT switches Q1 and Q2 is likely to damage them.

[0004] Therefore, it is urgent to design a fast-frequency pulse TIG arc additive system that adopts an arc starting structure and arc starting method different from the existing technology to ensure successful arc starting in the additive process. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide a fast-frequency TIG arc additive system and additive method; the additive system disconnects the fast-frequency pulse main circuit before the arc is successfully started, preventing the arc-starting high-frequency high-voltage electricity from being introduced into the fast-frequency pulse main circuit, protecting the main circuit electronic components from being damaged by the high-frequency high-voltage electricity, and ensuring arc-starting stability.

[0006] To achieve the above-mentioned object, the present invention is implemented through the following technical solutions: a fast-frequency TIG arc additive system, comprising a fast-frequency pulse current main circuit, a base current main circuit, a control circuit, and a high-frequency high-voltage arc ignition circuit; the input ends of the fast-frequency pulse current main circuit and the base current main circuit are respectively connected to an external power supply through a rectifier and filter circuit; the output end of the fast-frequency pulse current main circuit is connected to a welding load through a relay K1; the output end of the base current main circuit is connected to the welding load, and the negative electrode of the output end of the base current main circuit is connected to a coupling inductor T3; the coupling inductor T3 is also connected to the high-frequency high-voltage arc ignition circuit to couple the high-frequency high-voltage arc ignition circuit with the negative electrode of the output end of the base current main circuit;

[0007] The control circuit is respectively connected to the fast-frequency pulse current main circuit and the base current main circuit to output a welding drive signal; the control circuit is respectively connected to the high-frequency high-voltage arc striking circuit and the relay K1; before arc striking, the control circuit controls the relay K1 to turn off to disconnect the fast-frequency pulse current main circuit, and controls the base current main circuit to output a base waveform, and controls the high-frequency high-voltage arc striking circuit to output arc striking high-frequency high-voltage electricity; the arc striking high-frequency high-voltage electricity is coupled and superimposed with the base waveform, and acts on the welding load to break through the air to generate an arc; after arc striking is successful, the control circuit controls the high-frequency high-voltage arc striking circuit to stop output, and controls the relay K1 to close, so that the fast-frequency pulse current main circuit and the base current main circuit are output in parallel, and superposition obtains a fast-frequency double-pulse current welding waveform.

[0008] Preferably, the output end of the base current main circuit is provided with a base current sensing module for sensing the output end current of the base current main circuit; and whether the arc starting is successful is determined by judging the current value detected by the base current sensing module.

[0009] Preferably, the fast-frequency pulse current main circuit and the base current main circuit both include a SiCMOSFET full-bridge inverter circuit, a high-frequency transformer, and a full-wave rectifier circuit connected in sequence; the fast-frequency pulse current main circuit also includes a high-frequency current switching circuit connected to the rear side of the full-wave rectifier circuit;

[0010] The control circuit is connected to the SiC MOSFET full-bridge inverter circuit of the fast-frequency pulse current main circuit and the base current main circuit through the SiC drive circuit respectively; the control circuit is connected to the high-frequency current switching circuit of the fast-frequency pulse current main circuit through the IGBT drive circuit.

[0011] Preferably, the high-frequency current switching circuit includes an IGBT switch tube Q1 and an IGBT switch tube Q2; the positive pole of the output end of the full-wave rectifier circuit of the fast-frequency pulse current main circuit is connected to the welding load through the series-connected filter inductor L1 and the IGBT switch tube Q1, and then the welding load is connected to the negative pole of the output end of the full-wave rectifier circuit of the fast-frequency pulse current main circuit through the relay K1; the connection point between the filter inductor L1 and the IGBT switch tube Q1 is connected to the negative pole of the output end of the full-wave rectifier circuit of the fast-frequency pulse current main circuit through the IGBT switch tube Q2; the IGBT switch tube Q1 and the IGBT switch tube Q2 are respectively connected with an absorption circuit in parallel.

[0012] Preferably, the SiC MOSFET full-bridge inverter circuit topology of the fast-frequency pulse current main circuit and the base current main circuit is the same; the full-wave rectifier circuit topology of the fast-frequency pulse current main circuit and the base current main circuit is the same; the SiCMOSFET full-bridge inverter circuit adopts a full-bridge inverter topology structure composed of four SiC MOSFET switching tubes; the full-wave rectifier circuit is composed of an ultra-fast recovery diode VD1 and an ultra-fast recovery diode VD2.

[0013] Preferably, it also includes a wire feeding drive circuit; the control circuit is also connected to an external wire feeding motor through the wire feeding drive circuit to control the wire feeding speed.

[0014] Preferably, the control circuit controls the wire feeding speed by controlling the pulse width of the pulse driving signal output by the wire feeding driving circuit; making the wire feeding speed peak value V p and base value V b Respectively with the fast frequency pulse waveform main current I output by the fast frequency pulse current main circuit p and the secondary current I b Synchronize so that the wire feed speed matches the stirring effect of the fast-frequency double-pulse current welding waveform on the molten pool.

[0015] The main current I p >Secondary current I b ; Wire feeding speed peak V p >Wire feeding speed base value V b .

[0016] The additive method of the fast-frequency TIG arc additive system includes the following steps:

[0017] S1. Input welding parameters and move to the starting point of the first track;

[0018] S2. Start the welding gun and disconnect the output end of the fast-frequency pulse current main circuit through relay K1; control the base current main circuit to output the base waveform, control the high-frequency high-voltage arc ignition circuit to output the arc ignition high-frequency high-voltage electricity, couple the arc ignition high-frequency high-voltage electricity to the negative electrode of the output end of the base current main circuit to be superimposed with the base waveform, and act on the welding load to break through the air to generate an arc; after the arc is successfully struck, the control circuit controls the high-frequency high-voltage arc ignition circuit to stop output and controls relay K1 to close, so that the fast-frequency pulse current main circuit and the base current main circuit are output in parallel;

[0019] S3, enter the fast frequency double pulse current welding waveform and wire feeding speed control:

[0020] When the fast-frequency pulse waveform output by the fast-frequency pulse current main circuit enters the main current I p During the phase, the control circuit timer performs timing; the control circuit controls the fast-frequency pulse current main circuit to output the fast-frequency pulse waveform peak value as the main current I p , control the base current main circuit to output base waveform, and control the wire feeding drive circuit to output pulse drive signal, the pulse width of the pulse drive signal is the peak value of the wire feeding speed V p The corresponding pulse width makes the wire feeding speed reach the peak value V p Until the control circuit timer completes the set main current I p time;

[0021] Then the fast-frequency pulse waveform output by the fast-frequency pulse current main circuit enters the auxiliary current I b In the stage, the control circuit timer performs timing; the control circuit controls the fast frequency pulse current main circuit output fast frequency pulse waveform peak value to the auxiliary current I b , control the base current main circuit to output base waveform, and control the wire feeding drive circuit to output pulse drive signal, the pulse width of the pulse drive signal is the wire feeding speed base value V b The corresponding pulse width makes the wire feeding speed reach the base value V b Until the control circuit timer completes the setting of the secondary current I b time;

[0022] Repeatedly enter the main current I p Phase and secondary current I b stage, until the end of the current trajectory is reached; the welding gun is turned off, the fast-frequency pulse current main circuit and the base current main circuit stop outputting current, the wire feeding motor stops feeding wire, and the relay K1 is turned off;

[0023] S4. Determine whether the additive task is completed: if not, move to the next trajectory starting point and jump to step S3; if completed, the additive task ends.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] 1. The terminal of the fast-frequency pulse current main circuit of the present invention is connected to a relay. The relay is disconnected before arc ignition is successful, preventing the arc-ignition high-frequency high-voltage electricity from being introduced into the fast-frequency pulse main circuit, thereby protecting the main circuit electronic components from being damaged by the high-frequency high-voltage electricity. The arc-ignition high-frequency high-voltage electricity is coupled with the output of the base current main circuit to act on the welding load to break through the air and generate an arc, thereby ensuring a high success rate of arc ignition during the additive process. After arc ignition is successful, the relay is connected again to connect the fast-frequency pulse current main circuit and the base current main circuit in parallel, and a fast-frequency double-pulse current welding waveform is output in a superimposed manner.

[0026] 2. The present invention realizes that the wire feeding speed changes with the current amplitude of the fast-frequency welding power supply by synchronously controlling the current parameters of the fast-frequency welding power supply and the wire feeding speed. This allows the welding wire to adopt a matching wire feeding speed at different current output stages of the fast-frequency welding power supply, thereby fully melting the welding wire, ensuring additive molding, reducing welding porosity, and improving additive quality.

[0027] 3. The present invention integrates the high-frequency welding power supply and the wire feeding motor drive into one, reducing the cost of welding equipment, reducing the interference in the interaction process between the high-frequency welding power supply and the wire feeding machine, and improving the accuracy of the synchronous control of the high-frequency welding power supply and the wire feeding motor;

[0028] 4. The present invention uses a fast-frequency TIG arc additive process to refine the grains of the additive parts, thereby improving the strength of the additive parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the schematic diagram of the fast-frequency additive power supply circuit of the existing fast-frequency TIG arc additive system;

[0030] Figure 2 This is a system block diagram of the fast-frequency TIG arc additive system of the present invention;

[0031] Figure 3 This is a circuit diagram of a fast-frequency additive power supply for a fast-frequency TIG arc additive system of the present invention;

[0032] Figure 4 1. is a system block diagram of a fast-frequency additive power supply of a fast-frequency TIG arc additive system of the present invention;

[0033] Figure 5 This is a flow chart of the additive method of the fast-frequency TIG arc additive system of the present invention;

[0034] Figure 6 Schematic diagram of the fast-frequency double-pulse current welding waveform and wire feeding speed waveform of the fast-frequency TIG arc additive system of the present invention;

[0035] Figure 7 1. It is a circuit schematic diagram of the wire feeding drive circuit of the fast-frequency TIG arc additive system of the present invention;

[0036] FIG8( a ) and FIG8 ( b ) are cross-sectional grain effect diagrams of a conventional fast-frequency pulse TIG additive component and a fast-frequency pulse TIG arc additive component of the present invention, respectively. DETAILED DESCRIPTION

[0037] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0038] Example

[0039] This embodiment is a fast frequency TIG arc additive system, such as Figure 2 As shown, it includes a host computer, a motion controller, a fast-frequency additive power supply, a welding robot, a wire feeding motor, a shielding gas device and a welding gun; the operator inputs the arc additive parameters and the additive planning trajectory into the host computer; the host computer parses the data and sends it to the motion controller; the motion controller transmits the motion instructions to the welding robot, and the welding gun moves along the additive trajectory with the welding robot; at the same time, the motion controller transmits the welding parameters and wire feeding parameters to the fast-frequency additive power supply through CAN communication; the fast-frequency additive power supply outputs a welding current waveform and generates an arc between the welding gun and the workpiece; at the same time, the welding power supply drives the wire feeding motor to feed the welding wire into the arc, and the arc melts the welding wire and stacks it along the welding trajectory to obtain an additive part.

[0040] like Figure 3 As shown, the fast-frequency additive power supply includes a fast-frequency pulse current main circuit, a base current main circuit, a control circuit and a high-frequency high-voltage arc ignition circuit; the input ends of the fast-frequency pulse current main circuit and the base current main circuit are respectively connected to the external power supply through a rectifier and filter circuit.

[0041] Both the fast-frequency pulse current main circuit and the base current main circuit include a SiC MOSFET full-bridge inverter circuit, a high-frequency transformer, and a full-wave rectifier circuit connected in sequence; the fast-frequency pulse current main circuit also includes a high-frequency current switching circuit connected to the rear side of the full-wave rectifier circuit.

[0042] The SiC MOSFET full-bridge inverter circuit topology of the fast-frequency pulse current main circuit and the base current main circuit is the same; the full-wave rectifier circuit topology of the fast-frequency pulse current main circuit and the base current main circuit is the same; the SiC MOSFET full-bridge inverter circuit adopts a full-bridge inverter topology composed of four SiC MOSFET switching tubes; the full-wave rectifier circuit consists of ultra-fast recovery diode VD1 and ultra-fast recovery diode VD2.

[0043] The high-frequency current switching circuit includes an IGBT switch tube Q1 and an IGBT switch tube Q2; the positive electrode of the output end of the full-wave rectifier circuit of the fast-frequency pulse current main circuit is connected to the welding load through the series-connected filter inductor L1 and IGBT switch tube Q1, and then the welding load is connected to the negative electrode of the output end of the full-wave rectifier circuit of the fast-frequency pulse current main circuit through the relay K1; the connection point between the filter inductor L1 and the IGBT switch tube Q1 is connected to the negative electrode of the output end of the full-wave rectifier circuit of the fast-frequency pulse current main circuit through the IGBT switch tube Q2.

[0044] The rectifier filter circuit rectifies 380V three-phase AC into DC voltage U in ; SiC MOSFET full-bridge inverter circuit converts DC voltage U in The voltage is inverted into a 100kHz AC voltage, which is then reduced to a low voltage on the secondary side by a high-frequency transformer T1 (turns ratio, 7:1). This high-frequency AC voltage on the secondary side is rectified to DC by a full-wave rectifier circuit, which then filters out the DC ripple by inductor L1. The DC current is converted into a 20kHz pulse current by alternating conduction of two IGBT switches, Q1 in parallel and Q2 in series, at a frequency of 20kHz. Resistor R1 and capacitor C1 act as a snubber circuit connected in parallel across Q1, while resistor R2 and capacitor C2 act as a snubber circuit for Q2.

[0045] The output of the fast-frequency pulse current main circuit is connected to the welding load via relay K1. The output of the base current main circuit is also connected to the welding load, and the negative terminal of the base current main circuit's output is connected to a coupling inductor T3. Coupling inductor T3 is also connected to a high-frequency, high-voltage arc ignition circuit to couple it to the negative terminal of the base current main circuit's output. This high-frequency, high-voltage arc ignition circuit can utilize an existing high-frequency, high-voltage arc ignition circuit.

[0046] The control circuit is connected to the fast-frequency pulse current main circuit and the base current main circuit to output a welding drive signal. The control circuit is also connected to the high-frequency, high-voltage arc ignition circuit and relay K1. Before arcing, the control circuit controls relay K1 to turn off to disconnect the fast-frequency pulse current main circuit, controls the base current main circuit to output a base waveform, and controls the high-frequency, high-voltage arc ignition circuit to output arc-ignition high-frequency, high-voltage electricity. The arc-ignition high-frequency, high-voltage electricity is coupled and superimposed with the base waveform, acting on the welding load to break through the air and generate an arc. A base current sensing module is provided at the output end of the base current main circuit for sensing the output current of the base current main circuit. The success of arc ignition is determined by judging the current value detected by the base current sensing module.

[0047] After the arc is successfully started, the control circuit controls the high-frequency and high-voltage arc starting circuit to stop output, and controls the relay K1 to close, so that the fast-frequency pulse current main circuit and the base current main circuit are output in parallel, and the fast-frequency double-pulse current welding waveform is obtained by superposition.

[0048] like Figure 4 As shown, the control circuit preferably includes a 32-bit high-speed ARM microprocessor, which generates fully digital PWM control signals that act on the wire feed drive circuit, SiC drive circuit, and IGBT drive circuit, respectively. Specifically, the SiC drive circuit is connected to the SiC MOSFET full-bridge inverter circuits of the fast-frequency pulse current main circuit and the base current main circuit, respectively; the control circuit is connected to the high-frequency current switching circuit of the fast-frequency pulse current main circuit through the IGBT drive circuit. The ARM microprocessor's GPIO interface controls the parallel connection of the two main circuits, shielding gas control, and arc ignition circuit switching through optocoupler isolation and relay isolation. The TIM timer is used to control the welding current waveform and the welding process. The control circuit is also connected to an electrical signal sampling and feedback module. The current sampling, voltage sampling circuit, and wire feed speed acquisition signals are magnetically isolated and signal conditioned before being input to the control circuit. The control circuit compares the output value with the preset value and changes the output PWM duty cycle to achieve closed-loop control of the power supply output current, voltage, and wire feed speed.

[0049] The host computer is used by the operator to input arc additive parameters and additive planning trajectory parameters. The host computer parses the user input data and sends it to the motion controller; the motion controller transmits the motion instructions to the welding robot, and the welding gun moves along the planned trajectory with the welding robot; at the same time, the motion controller transmits the welding parameters and wire feeding parameters to the fast-frequency additive power supply through CAN communication.

[0050] In traditional high-frequency TIG arc additive systems, the high-frequency pulse TIG power supply and wire feeder are controlled separately using different control circuits. When the high-frequency pulse TIG power supply outputs the welding current waveform for the welding gun and performs pulsed current welding, the wire feed drive waveform is not synchronized. For example, when the high-frequency pulse TIG power supply output is at the base value stage of the current welding waveform, due to the low welding current and heat input, using a fast wire feed speed during this stage will prevent the wire from fully melting, affecting the quality of the additive part, creating many pores in the additive part, and even preventing the part from forming.

[0051] To solve this problem, the fast-frequency TIG arc additive system preferably also includes a wire feeding drive circuit; the control circuit is also connected to an external wire feeding motor through the wire feeding drive circuit to control the wire feeding speed.

[0052] The control circuit controls the wire feeding speed by controlling the pulse width of the pulse drive signal output by the wire feeding drive circuit; the wire feeding speed peak value V p and base value V b Respectively with the fast frequency pulse waveform main current I output by the fast frequency pulse current main circuit p and the secondary current I bSynchronize so that the wire feed speed matches the stirring effect of the fast-frequency double-pulse current welding waveform on the molten pool.

[0053] The present invention synchronously controls the current parameters of the high-frequency welding power supply and the wire feeding speed, thereby achieving a change in the wire feeding speed as the current amplitude of the high-frequency welding power supply changes, so that the welding wire can adopt a matching wire feeding speed in different current output stages of the high-frequency welding power supply, thereby fully melting the welding wire, ensuring additive molding, reducing welding porosity, and improving the quality of additive manufacturing; the high-frequency welding power supply is integrated with the wire feeding motor drive, reducing the cost of welding equipment, reducing the interference in the interaction process between the high-frequency welding power supply and the wire feeder, and improving the accuracy of the synchronous control of the high-frequency welding power supply and the wire feeding motor.

[0054] The above-mentioned fast frequency TIG arc additive system additive method, such as Figure 5 As shown, the following steps are included:

[0055] S1. Input welding parameters and move to the starting point of the first track;

[0056] S2, start the welding gun, disconnect the output end of the fast frequency pulse current main circuit through the relay K1; control the base current main circuit to output the base value waveform. In this embodiment, the base value waveform is the base value current I D , control the high-frequency and high-voltage arc striking circuit to output high-frequency and high-voltage arc striking electricity, the high-frequency and high-voltage arc striking electricity is coupled to the negative electrode of the output terminal of the base current main circuit to be superimposed with the base waveform, and acts on the welding load to break through the air and generate an arc; the current Hall sensor converts the current value of the base current main circuit and inputs it into the control circuit, the control circuit determines whether the current of the base current main circuit reaches the set arc striking current value, if not, the relay K1 is still disconnected, the high-frequency and high-voltage arc striking circuit continues to work, if the current of the base current main circuit reaches the set arc striking current value, it is determined that the arc striking is successful;

[0057] After arcing is successful, the control circuit controls the high-frequency and high-voltage arc ignition circuit to stop outputting, and controls relay K1 to close, so that the fast-frequency pulse current main circuit and the base current main circuit are output in parallel;

[0058] S3, enter the fast frequency double pulse current welding waveform and wire feeding speed control; Figure 6 The figure below shows the fast-frequency double-pulse current welding waveform and wire feeding speed waveform:

[0059] When the fast-frequency pulse waveform output by the fast-frequency pulse current main circuit enters the main current I p During the phase, the control circuit timer performs timing; the control circuit controls the fast-frequency pulse current main circuit to output the fast-frequency pulse waveform peak value as the main current I p , control the base current main circuit to output the base waveform. In this embodiment, the base waveform is the base current ID , and controls the wire feeding drive circuit to output a pulse drive signal, the pulse width of the pulse drive signal is the peak value of the wire feeding speed V p The corresponding pulse width makes the wire feeding speed reach the peak value V p Until the control circuit timer completes the set main current I p time;

[0060] Then the fast-frequency pulse waveform output by the fast-frequency pulse current main circuit enters the auxiliary current I b In the stage, the control circuit timer performs timing; the control circuit controls the fast frequency pulse current main circuit output fast frequency pulse waveform peak value to the auxiliary current I b , control the base current main circuit to output base waveform, and control the wire feeding drive circuit to output pulse drive signal, the pulse width of the pulse drive signal is the wire feeding speed base value V b The corresponding pulse width makes the wire feeding speed reach the base value V b Until the control circuit timer completes the setting of the secondary current I b time;

[0061] Main current I p >Secondary current I b ; Wire feeding speed peak V p >Wire feeding speed base value V b ;

[0062] Repeatedly enter the main current I p Phase and secondary current I b stage, until the end of the current trajectory is reached; the welding gun is turned off, the fast-frequency pulse current main circuit and the base current main circuit stop outputting current, the wire feeding motor stops feeding wire, and the relay K1 is turned off;

[0063] S4. Determine whether the additive task is completed: if not, move to the next trajectory starting point and jump to step S3; if completed, the additive task ends.

[0064] Wire feeding drive circuit such as Figure 7 As shown, it includes a driver chip model IR2110, a bootstrap circuit and a motor half-bridge drive circuit.

[0065] Figure 8 (a) and Figure 8 (b) are cross-sectional grain effects of the fast-frequency pulse TIG asynchronous wire feeding arc additive part and the fast-frequency pulse TIG synchronous wire feeding arc additive part of the present invention. When the fast-frequency asynchronous wire feeding process is used, in order to ensure the molding of the additive part, it is necessary to ensure that the welding wire is under the auxiliary current I b The process of TIG synchronous wire feeding can be increased by increasing the main current I.p The wire feeding speed is increased in different stages, so that the thickness of each layer of the additive part increases, and the increased wire feeding amount can absorb the heat of the peak current, reduce the heat accumulation of the additive part, increase the cooling rate of the molten pool, and cause a large number of equiaxed crystals to appear during the solidification growth process of the molten pool, refine the grain of the additive part, and improve the mechanical properties of the additive part.

[0066] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A fast-frequency TIG arc additive system, characterized by: It includes a fast-frequency pulse current main circuit, a base current main circuit, a control circuit, and a high-frequency, high-voltage arc ignition circuit; the input ends of the fast-frequency pulse current main circuit and the base current main circuit are respectively connected to an external power supply through a rectifier and filter circuit; the output end of the fast-frequency pulse current main circuit is connected to a welding load through a relay K1; the output end of the base current main circuit is connected to the welding load, and the negative electrode of the output end of the base current main circuit is connected to a coupling inductor T3; the coupling inductor T3 is also connected to the high-frequency, high-voltage arc ignition circuit to couple the high-frequency, high-voltage arc ignition circuit with the negative electrode of the output end of the base current main circuit; The control circuit is connected to the fast-frequency pulse current main circuit and the base current main circuit respectively to output a welding drive signal; the control circuit is connected to the high-frequency high-voltage arc ignition circuit and the relay K1 respectively; Before arc starting, the control circuit controls relay K1 to turn off to disconnect the fast-frequency pulse current main circuit, and controls the base current main circuit to output the base waveform, and controls the high-frequency and high-voltage arc starting circuit to output the arc starting high-frequency and high-voltage electricity; the arc starting high-frequency and high-voltage electricity is coupled and superimposed with the base waveform, and acts on the welding load to break through the air to generate an arc; after the arc is successfully started, the control circuit controls the high-frequency and high-voltage arc starting circuit to stop output, and controls relay K1 to close, so that the fast-frequency pulse current main circuit and the base current main circuit are output in parallel, and the superposition obtains a fast-frequency double-pulse current welding waveform.

2. The fast-frequency TIG arc additive system according to claim 1, characterized in that: The output end of the base current main circuit is provided with a base current sensing module for sensing the output end current of the base current main circuit; by judging the current value detected by the base current sensing module, it is judged whether the arc is started successfully.

3. The fast-frequency TIG arc additive system according to claim 1, characterized in that: The fast-frequency pulse current main circuit and the base current main circuit both include a SiC MOSFET full-bridge inverter circuit, a high-frequency transformer, and a full-wave rectifier circuit connected in sequence; the fast-frequency pulse current main circuit also includes a high-frequency current switching circuit connected to the rear side of the full-wave rectifier circuit; The control circuit is connected to the SiCMOSFET full-bridge inverter circuit of the fast-frequency pulse current main circuit and the base current main circuit through the SiC drive circuit respectively; the control circuit is connected to the high-frequency current switching circuit of the fast-frequency pulse current main circuit through the IGBT drive circuit.

4. The fast-frequency TIG arc additive system according to claim 3, characterized in that: The high-frequency current switching circuit includes an IGBT switch tube Q1 and an IGBT switch tube Q2; the positive electrode of the output end of the full-wave rectifier circuit of the fast-frequency pulse current main circuit is connected to the welding load through a filter inductor L1 and an IGBT switch tube Q1 connected in series, and then the welding load is connected to the negative electrode of the output end of the full-wave rectifier circuit of the fast-frequency pulse current main circuit through a relay K1; the connection point between the filter inductor L1 and the IGBT switch tube Q1 is connected to the negative electrode of the output end of the full-wave rectifier circuit of the fast-frequency pulse current main circuit through the IGBT switch tube Q2; the IGBT switch tube Q1 and the IGBT switch tube Q2 are respectively connected in parallel with an absorption circuit.

5. The fast-frequency TIG arc additive system according to claim 3, characterized in that: The SiC MOSFET full-bridge inverter circuit topology of the fast-frequency pulse current main circuit and the base current main circuit is the same; the full-wave rectifier circuit topology of the fast-frequency pulse current main circuit and the base current main circuit is the same; the SiC MOSFET full-bridge inverter circuit adopts a full-bridge inverter topology structure composed of four SiCMOSFET switching tubes; the full-wave rectifier circuit is composed of an ultra-fast recovery diode VD1 and an ultra-fast recovery diode VD2.

6. The fast-frequency TIG arc additive system according to claim 1, characterized in that: It also includes a wire feeding drive circuit; the control circuit is also connected to an external wire feeding motor through the wire feeding drive circuit to control the wire feeding speed.

7. The fast-frequency TIG arc additive system according to claim 6, characterized in that: The control circuit controls the wire feeding speed by controlling the pulse width of the pulse driving signal output by the wire feeding driving circuit; p and base value V b Respectively with the fast frequency pulse waveform main current I output by the fast frequency pulse current main circuit p and the secondary current I b Synchronize so that the wire feed speed matches the stirring effect of the fast-frequency double-pulse current welding waveform on the molten pool.

8. The fast-frequency TIG arc additive system according to claim 7, characterized in that: The main current I p >Secondary current I b ; Wire feeding speed peak V p >Wire feeding speed base value V b .

9. The method for adding materials using a fast-frequency TIG arc adding material system according to claim 7, characterized in that: The steps include: S1. Input welding parameters and move to the starting point of the first track; S2. Start the welding gun and disconnect the output end of the fast-frequency pulse current main circuit through relay K1; control the base current main circuit to output the base waveform, control the high-frequency high-voltage arc ignition circuit to output the arc ignition high-frequency high-voltage electricity, couple the arc ignition high-frequency high-voltage electricity to the negative electrode of the output end of the base current main circuit to be superimposed with the base waveform, and act on the welding load to break through the air to generate an arc; after the arc is successfully struck, the control circuit controls the high-frequency high-voltage arc ignition circuit to stop output and controls relay K1 to close, so that the fast-frequency pulse current main circuit and the base current main circuit are output in parallel; S3, enter the fast frequency double pulse current welding waveform and wire feeding speed control: When the fast-frequency pulse waveform output by the fast-frequency pulse current main circuit enters the main current I p During the phase, the control circuit timer performs timing; the control circuit controls the fast-frequency pulse current main circuit to output the fast-frequency pulse waveform peak value as the main current I p , control the base current main circuit to output base waveform, and control the wire feeding drive circuit to output pulse drive signal, the pulse width of the pulse drive signal is the peak value of the wire feeding speed V p The corresponding pulse width makes the wire feeding speed reach the peak value V p Until the control circuit timer completes the set main current I p time; Then the fast-frequency pulse waveform output by the fast-frequency pulse current main circuit enters the auxiliary current I b In the stage, the control circuit timer performs timing; the control circuit controls the fast frequency pulse current main circuit output fast frequency pulse waveform peak value to the auxiliary current I b , control the base current main circuit to output base waveform, and control the wire feeding drive circuit to output pulse drive signal, the pulse width of the pulse drive signal is the wire feeding speed base value V b The corresponding pulse width makes the wire feeding speed reach the base value V b Until the control circuit timer completes the setting of the secondary current I b time; Repeatedly enter the main current I p Phase and secondary current I b stage, until reaching the end of the current trajectory; The welding gun is turned off, the fast-frequency pulse current main circuit and the base current main circuit stop outputting current, the wire feeding motor stops feeding wire, and relay K1 is turned off; S4. Determine whether the additive task is completed: if not, move to the next trajectory starting point and jump to step S3; If completed, the additive process is complete.

Images