Laser-ultrahigh frequency pulse arc hybrid welding device

Abstract

A laser-ultrahigh frequency pulse arc hybrid welding device comprises a welding gun arranged on a motion execution mechanism, a laser welding head, and an ultrahigh frequency pulse current generating device, a welding power supply and a laser which are respectively connected with the laser welding head, wherein the motion executing mechanism, the welding power source and the laser are connected with the control module to transmit and control laser parameters, motion parameters and electric arc welding parameters, laser beams generated by the laser are input into the laser welding head through optical fibers, and the ultrahigh-frequency pulse current generating device generates ultrahigh-frequency pulse welding current and is connected with the welding power source in parallel. The output end of the welding power source is connected with the welding gun and the workpiece to form a loop, and therefore high-frequency compression electric arcs are generated between the welding gun and the workpiece. The stiffness and stability of the electric arc are improved through the ultrahigh frequency pulse current and the high-frequency compression effect of the ultrasonic electric arc.

Description

Technical Field

[0001] The present invention relates to the technology in the field of welding equipment, in particular to a laser-ultra-high frequency pulse arc composite welding device. Background Art

[0002] Laser-arc hybrid welding is a technology that uses both laser and arc as heat sources to melt materials and then connect them. The arc heat source is usually TIG arc or MIG / MAG arc. There is a mutual attraction between laser plasma and arc, while the traditional arc energy diverges and has low stiffness. Due to the laser attraction, the arc deviates from the axis of the welding gun, resulting in a decrease in arc penetration and even poor droplet transition stability, which is prone to defects such as spatter. In order to improve the arc stiffness and stability, the existing technology achieves arc compression by applying a high-frequency magnetic field to make the arc energy more concentrated. However, the generation of a high-frequency magnetic field requires the addition of an additional excitation power supply and excitation coil, which will undoubtedly increase the complexity of the laser arc hybrid welding gun, limit flexibility and applicability, and the coupling of the external magnetic field with the welding current will cause welding current distortion. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention proposes a laser-ultra-high frequency pulse arc hybrid welding device, which improves arc stiffness and stability by using ultra-high frequency pulse current and the high-frequency compression effect of ultrasonic arc.

[0004] The present invention is achieved through the following technical solutions:

[0005] The invention relates to a laser-ultra-high frequency pulse arc hybrid welding device, comprising: a welding gun arranged on a motion actuator, a laser welding head, and an ultra-high frequency pulse current generating device, a welding power source and a laser respectively connected thereto, wherein: the motion actuator, the welding power source and the laser are respectively connected to a control module to transmit and control laser parameters, motion parameters and arc welding parameters, a laser beam generated by the laser is input to the laser welding head through an optical fiber, the ultra-high frequency pulse current generating device generates an ultra-high frequency pulse welding current and is connected in parallel with the welding power source, and an output end of the welding power source is respectively connected to the welding gun and a workpiece to form a loop, thereby generating a high-frequency compression arc between the welding gun and the workpiece.

[0006] The present invention relates to a laser-ultra-high frequency pulse arc hybrid welding method based on the above system, comprising:

[0007] Step 1: Prepare the workpiece to be welded, clamp it and fix it on the workbench;

[0008] Step 2: Adjust the motion actuator posture, write the motion program and verify the welding trajectory;

[0009] Step 3: Adjust the motion actuator to the welding starting position, set the laser parameters (laser power, swing mode, defocus amount) on the laser, set the welding parameters (welding current, welding voltage, wire feeding speed) on the welding power supply, set the ultra-high frequency pulse current parameters (pulse current, pulse frequency, duty cycle) on the ultra-high frequency pulse current generator, turn on the laser, welding power supply and ultra-high frequency pulse current generator, and start welding;

[0010] Step 4: The motion actuator moves to the welding end position, stops the laser, welding power supply and ultra-high frequency pulse welding device, and ends the welding. Technical Effects

[0011] The present invention uses ultra-high frequency pulse welding current to generate high-frequency compression arc, which shrinks the arc, increases the stiffness, and improves the arc stability. The equipment is simple, no additional excitation device is required, and no change in the welding gun structure is required, and no welding current distortion is caused. The ultra-high frequency pulse current is a square wave, and the rising and falling edges of the current change at a fast rate, so the pulse frequency and amplitude are higher than the external magnetic field method. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the present invention;

[0013] Figure 2 This is the principle diagram of the ultra-high frequency pulse current generating device;

[0014] Figure 3 This is the timing diagram of the control signal of the ultra-high frequency pulse current generating device;

[0015] Figure 4 It is a schematic diagram of the laser-ultra-high frequency pulse TIG hybrid welding principle and current waveform of the present invention;

[0016] Figure 5 It is the principle diagram of laser-ultra-high frequency pulse MIG composite welding and the schematic diagram of current waveform of the present invention;

[0017] Figure 6 For the corresponding Figure 4 Current waveform diagram;

[0018] Figure 7 For the corresponding Figure 5 The current waveform diagram in ;

[0019] Figure 8 Schematic diagram of arc contraction and grain refinement effect after adding high frequency. DETAILED DESCRIPTION

[0020] like Figure 1As shown, this embodiment relates to a laser-ultra-high frequency pulse arc hybrid welding device, comprising: a welding gun a6, a laser welding head a7, and a welding power source a4 and a laser a1 respectively connected to the motion actuator a2, wherein: the motion actuator a2, the welding power source a4 and the laser a1 are respectively connected to the control module a3 to transmit and control laser parameters, motion parameters and arc welding parameters, and the laser beam generated by the laser a1 is input to the laser welding head a7 through the optical fiber a8. The ultra-high frequency pulse welding current generating device a5 generates an ultra-high frequency pulse welding current and is connected in parallel with the welding power source a4. The output end of the welding power source a4 is respectively connected to the welding gun a6 and the workpiece through a cable, and a high-frequency compression arc is generated between the welding gun a6 and the workpiece. The welding gun a6 and the laser welding head are fixed at the end of the motion actuator a2. The control module a3 is connected to the laser a1, the motion actuator a2 and the welding power source a4 through a control cable.

[0021] The welding power supply a4 adopts TIG welding power supply, plasma welding power supply or MIG / MAG welding power supply. When TIG or plasma arc welding power supply is adopted, the welding gun a6 is connected to the negative pole of welding power supply a4, and the workpiece is connected to the positive pole of welding power supply a4; when MIG / MAG power supply is adopted, the welding gun is connected to the positive pole of welding power supply a4, and the workpiece is connected to the negative pole of welding power supply a4.

[0022] like Figure 2 As shown, the ultra-high frequency pulse current generating device a5 comprises: an AC / DC current source b1, a pulse chopping circuit b2, and an ultra-high frequency pulse current controller b3, wherein: the AC / DC current source b1 is connected in series with the pulse chopping circuit b2, the input of the AC / DC current source b1 is a three-phase 380V / 50Hz alternating current, and the output is a direct current of 0 to 100A, the pulse chopping circuit b2 can generate an ultra-high frequency pulse current Ip, the pulse frequency is adjustable from 20kHz to 100kHz, the pulse current amplitude is adjustable from 0 to 100A, and the duty cycle is 0 to 100kHz. 100% adjustable, the ultra-high frequency pulse current controller b3 performs digital processing according to the pulse current amplitude, frequency, and duty cycle signals, respectively: output current control signal Ig to AC / DC current source b1, used to adjust the output current Ia of AC / DC current source b1, output control signal to AC / DC current source b1, used to control the switch of output current Ia, output pulse modulation signal PWM to pulse chopping circuit b2, used to generate two complementary drive signals P1 and P2, and adjust the frequency and duty cycle of output pulse current Ip.

[0023] When the control signal changes from high level to low level, the current source stops working, and the output current Ia of the current source b1 gradually decreases to zero. The output current Ip of the ultra-high frequency pulse current generator also becomes zero. When the control signal remains at a high level, the output current Ip of the ultra-high frequency pulse current generator is a series of pulse currents, and its pulse amplitude is equal to the output current Ia of the previous current source. By changing the magnitude of the current Ia and the frequency and duty cycle of the pulse modulation signal PWM, ultra-high frequency pulse currents with different amplitudes, frequencies, and duty cycles can be obtained.

[0024] like Figure 2 As shown, the pulse chopping circuit b2 includes: power switch tubes Q1, Q2, a third diode D1, a first diode DP1, a second diode DP2, a logic processing circuit b21 and a peak energy absorption circuit b22, wherein: the first switch tube Q1 is connected across the positive and negative poles of the input end of the pulse chopping circuit b2, that is, between the input end and the output end of the peak energy absorption circuit b22, the third diode D1 and the second switch tube Q2 are respectively arranged between the positive pole of the input end and the positive pole of the output end and between the negative pole of the input end and the negative pole of the output end of the pulse chopping circuit b2, the first and second first diodes DP1, DP2 are respectively arranged between the positive pole of the input end of the pulse chopping circuit b2 and the input end of the peak energy absorption circuit b22 and between the input end of the peak energy absorption circuit b22 and the negative pole of the output end of the pulse chopping circuit b2, and the logic processing circuit b21 generates two complementary drive signals P1, P2, which respectively drive the switch tubes Q1 and Q2 to be alternately turned on and off.

[0025] When Q1 is turned on and Q2 is turned off, the current source b1 outputs current Ia from the positive end of the current source b1 through Q1 and flows back to the negative end of the current source b1. At this time, the output current of the ultra-high frequency pulse current generating device is zero; when Q1 is turned off and Q2 is turned on, the current Ia forms a loop through the third diode D1, welding gun / workpiece, and Q2, and flows back to the negative end of the current source b1. At this time, the high frequency pulse current generating device outputs current Ip, which is equal to the current Ia.

[0026] The frequency and duty cycle of the driving signals P1 and P2 are determined by the pulse modulation signal PWM from the ultra-high frequency pulse current controller b3.

[0027] The first diodes DP1 and DP2 are clamping diodes used to clamp the peak voltage when the switch tubes Q1 and Q2 are turned off.

[0028] The peak energy absorption circuit b22 is used to absorb the voltage spike generated when the switch tubes Q1 and Q2 are turned off, so as to protect Q1 and Q2 from being damaged.

[0029] After specific practical experiments, the present invention was applied to high-strength steel welding. Under the same average current conditions, when an ultra-high frequency pulse current with a frequency of 20kHz, an amplitude of 100A, and a duty cycle of 50% was added, the arc energy density increased by more than 2 times, and the grain size decreased by about 30%. Figure 4 and Figure 6 As shown, TIG welding power source is used as welding power source a4, and the schematic diagram of laser-arc hybrid welding head is as shown in Figure 4 As shown in c1, the welding gun a6 is connected to the negative electrode of the TIG welding power supply output, the workpiece is connected to the positive electrode, the arc cathode (tungsten electrode) does not melt, and the welding wire a9 is fed into the molten pool below the electrode from the outside of the welding gun. When performing DC TIG hybrid welding, the DC current waveform output by the welding power supply a4 is shown in c2, and the current waveform output by the ultra-high frequency pulse current generator a5 is shown in Figure 4 As shown in c3. Since the output end of the ultra-high frequency pulse current generator is connected in parallel with the TIG welding power supply, the current waveform flowing through the welding gun is as follows: Figure 4 As shown in c4.

[0030] When MIG welding power source is used as welding power source a4, its schematic diagram and current waveform diagram are as follows: Figure 5 As shown. At this time, the laser-arc hybrid welding joint is as follows Figure 5 As shown in d1, the welding gun a6 is connected to the positive output of the MIG welding power supply, the workpiece is connected to the negative electrode, the welding wire is used as the arc anode, and the welding wire a9 is fed into the molten pool below the arc inside the welding gun and a molten droplet transfer occurs. When pulse MIG hybrid welding is performed, the pulse current waveform output by the welding power supply a4 is as follows Figure 5 and Figure 7 As shown in d2 (the pulse frequency is only tens to hundreds of Hz), the current waveform diagram output by the ultra-high frequency pulse current generator a5 is shown in d3. Since the output end of the ultra-high frequency pulse current generator is connected in parallel with the MIG welding power supply, the current waveform flowing through the welding gun is as shown in Figure 5 As shown in d4.

[0031] like Figure 8 As shown, compared with the prior art, the present invention increases the welding current pulse frequency to above 20kHz, achieving arc ultrasonic effect, thereby improving arc stiffness, refining grains, and improving the strength and toughness of the welded joint.

[0032] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. A laser-ultra-high frequency pulse arc hybrid welding device, characterized in that: include: A welding gun, a laser welding head and an ultra-high frequency pulse current generating device, a welding power supply and a laser are arranged on a motion actuator, and are respectively connected thereto, wherein: the motion actuator, the welding power supply and the laser are respectively connected to a control module to transmit and control laser parameters, motion parameters and arc welding parameters, the laser beam generated by the laser is input to the laser welding head through an optical fiber, the ultra-high frequency pulse current generating device generates an ultra-high frequency pulse welding current and is connected in parallel with the welding power supply, and the output end of the welding power supply is respectively connected to the welding gun and the workpiece to form a loop, thereby generating a high-frequency compression arc between the welding gun and the workpiece.

2. The laser-ultra-high frequency pulse arc hybrid welding device according to claim 1 is characterized in that: The welding power supply adopts TIG welding power supply, plasma welding power supply or MIG / MAG welding power supply. When TIG or plasma arc welding power supply is adopted, the welding gun is connected to the negative electrode of the welding power supply, and the workpiece is connected to the positive electrode of the welding power supply; when MIG / MAG power supply is adopted, the welding gun is connected to the positive electrode of the welding power supply, and the workpiece is connected to the negative electrode of the welding power supply.

3. The laser-ultra-high frequency pulse arc hybrid welding device according to claim 1 is characterized in that: The ultra-high frequency pulse current generating device comprises: an AC / DC current source, a pulse chopping circuit, and an ultra-high frequency pulse current controller, wherein: the AC / DC current source is connected in series with the pulse chopping circuit, the input of the AC / DC current source is a three-phase 380V / 50Hz alternating current, and the output is a direct current of 0 to 100A, the pulse chopping circuit can generate an ultra-high frequency pulse current Ip, the pulse frequency is adjustable from 20kHz to 100kHz, the pulse current amplitude is adjustable from 0 to 100A, and the duty cycle is adjustable from 0 to 100%, and the ultra-high frequency pulse current controller performs digital processing according to the pulse current amplitude, frequency, and duty cycle signals, respectively: outputting a current control signal Ig to the AC / DC current source for adjusting the size of the output current Ia of the AC / DC current source, the output current Ia of the AC / DC current source, the output current Ia of the AC / DC current source, the output current Ib of the AC / DC current source, the output current Ic of the AC / DC current source, the output current Id ...d of the AC / DC current source, the Output a control signal to the AC / DC current source to control the switch of the output current Ia, and output a pulse modulation signal PWM to the pulse chopper circuit to generate two complementary drive signals P1 and P2 to adjust the frequency and duty cycle of the output pulse current Ip; when the control signal changes from a high level to a low level, the current source stops working, the current source output current Ia gradually decreases to zero, and the output current Ip of the ultra-high frequency pulse current generating device also becomes zero. When the control signal remains at a high level, the output current Ip of the ultra-high frequency pulse current generating device is a series of pulse currents, and its pulse amplitude is equal to the output current Ia of the previous current source. By changing the size of the current Ia and the frequency and duty cycle of the pulse modulation signal PWM, ultra-high frequency pulse currents with different amplitudes, frequencies, and duty cycles can be obtained.

4. The laser-ultra-high frequency pulse arc hybrid welding device according to claim 1 is characterized in that: The pulse chopper circuit comprises: two switch tubes, two diodes for clamping the peak voltage when the two switch tubes are turned off, a third diode, a logic processing circuit and a peak energy absorption circuit, wherein: the first switch tube is connected across the positive and negative poles of the input end of the pulse chopper circuit, that is, between the input end and the output end of the peak energy absorption circuit, the third diode and the second switch tube are respectively arranged between the positive pole of the input end and the positive pole of the output end and between the negative pole of the input end and the negative pole of the output end of the pulse chopper circuit, the first and second diodes are respectively arranged between the positive pole of the input end of the pulse chopper circuit and the input end of the peak energy absorption circuit and the peak energy absorption circuit Between the input end and the negative pole of the output end of the pulse chopper circuit, the logic processing circuit generates two complementary drive signals P1 and P2, which respectively drive the two switch tubes to be alternately turned on and off; when the first switch tube is turned on and the second switch tube is turned off, the current source output current Ia flows from the positive end of the current source through the first switch tube back to the negative end of the current source. At this time, the output current of the ultra-high frequency pulse current generating device is zero; when the first switch tube is turned off and the second switch tube is turned on, the current Ia forms a loop through the third diode, the welding gun / workpiece, and the second switch tube, and flows back to the negative end of the current source. At this time, the high-frequency pulse current generating device outputs a current Ip, which is equal to the current Ia.

5. A laser-ultra-high frequency pulse arc hybrid welding method according to any one of claims 1 to 4, characterized in that: include: Step 1: Prepare the workpiece to be welded, clamp it and fix it on the workbench; Step 2: Adjust the motion actuator posture, write the motion program and verify the welding trajectory; Step 3: Adjust the motion actuator to the welding starting position, set the laser power, swing mode and defocus amount on the laser, set the welding current, welding voltage and wire feeding speed on the welding power supply, set the pulse current amplitude, pulse frequency and duty cycle of the ultra-high frequency pulse current on the ultra-high frequency pulse current generator, turn on the laser, welding power supply and ultra-high frequency pulse current generator, and start welding; Step 4: The motion actuator moves to the welding end position, stops the laser, welding power supply and ultra-high frequency pulse welding device, and ends the welding.

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