Plasma welding device for metal fittings

Abstract

The invention provides a metal fitting plasma welding device, and relates to the technical field of welding equipment, the metal fitting plasma welding device comprises a high-frequency pulse plasma modulation power supply system, a two-stage rotating electrode, a self-adaptive cooling system, a multi-dimensional collaborative cooling module and an intelligent welding seam tracking system, and the multi-dimensional collaborative cooling module comprises a welding head. In the multi-dimensional collaborative cooling module, the middle of a welding head is hollow, a jacket is a cooling water cavity, the upper end of the welding head is connected with a cooling water inlet pipe, cooling water nozzles with the inner diameter being 2 mm, the water flow speed being 4 m / s and the heat dissipation power being larger than or equal to 2 kW are annularly distributed at the bottom, and the surfaces of the cooling water nozzles are coated with high-radiance ceramic coatings to strengthen heat dissipation, so that the temperature of a welding area is effectively reduced. Mixed gas is input into the protective gas uniform distribution ring through the argon and hydrogen mixed gas inlet pipe, the ring wheel is pushed to rotate through the one-way inclined communicating pipe, then the mixed gas is guided by the protective gas uniform distribution ring to uniformly flow downwards, and a laminar flow barrier is formed at the gas curtain flow speed of 10 m / s through the flow guide ring skirt and the 45-degree included angle gas curtain guide plate, so that a welding area is protected against external interference.

Description

Technical Field

[0001] The invention relates to the technical field of welding equipment, and in particular to a plasma welding device for metal accessories. Background Art

[0002] In the metal processing industry, welding technology has always been one of the key processes for connecting metal parts. Although traditional welding methods, such as TIG welding and MIG welding, have met the needs of industrial production to a certain extent, they often have problems such as low welding efficiency, unstable weld quality, wide heat-affected zone, and short electrode life when facing specific materials such as aluminum alloys. These problems are particularly prominent in fields with high requirements for welding accuracy and surface quality, such as aerospace and automobile manufacturing.

[0003] Aluminum alloys, especially 6061 aluminum alloys, are widely used in the above fields due to their good mechanical properties and corrosion resistance. However, the high thermal conductivity and easy oxidation of aluminum alloys bring challenges to welding. Traditional welding methods are difficult to effectively control the heat input during welding, resulting in insufficient weld penetration, excessive heat-affected zone, and even defects such as burn-through and pores. In addition, the serious wear of electrodes during welding not only increases production costs, but also affects the continuity and stability of welding. Plasma welding, as an advanced welding method, is regarded as an effective way to solve the above problems due to its high energy density, good arc stability, and strong controllability of heat input. However, existing plasma welding devices still have deficiencies in high-frequency pulse control, arc stability, cooling efficiency, electrode life, and weld tracking, and are difficult to meet the needs of high-quality and high-efficiency welding. Summary of the invention

[0004] The invention relates to a metal fitting plasma welding device, which can accurately control high-frequency pulse waveform, improve arc stability, optimize cooling system, prolong electrode life and realize intelligent weld tracking.

[0005] The present invention provides a metal fitting plasma welding device, which specifically comprises: a high-frequency pulse plasma modulation power supply system, a two-stage rotating electrode, an adaptive cooling system, a multi-dimensional collaborative cooling module and an intelligent weld tracking system, wherein the multi-dimensional collaborative cooling module comprises a welding head, a protective gas injection sleeve and a protective gas uniform distribution ring, the outer annular sheath of the welding head is a protective gas injection sleeve, and a protective gas uniform distribution ring is arranged above the protective gas injection sleeve; the high-frequency pulse plasma modulation power supply system is composed of a high-frequency pulse waveform control module and an arc shape sensor, the arc shape sensor is installed at the outlet of the welding head, and the high-frequency pulse waveform control module ... It is hung on the upper end of the outer wall of the shell of the welding head; the two-stage rotating electrode is composed of a main electrode and an auxiliary electrode, and the cooling structures on the main electrode and the auxiliary electrode respectively constitute an adaptive cooling system; the electrode seat is fixedly installed on the upper end of the cavity of the welding head, the main electrode is fixed on the electrode seat, the rotating seat is rotatably installed on the main electrode, and the auxiliary electrode is vertically rotatably installed on the rotating seat and rotates with the main electrode as the rotation axis; an axial adjustment frame for adjusting the upper and lower positions of the main electrode is provided on the welding head above the electrode seat, and an arc-starting gas inlet pipe for introducing arc-starting gas is provided on the electrode seat; the intelligent weld tracking system is composed of a visual sensor combination and an AI algorithm module.

[0006] Optionally, the welding head is a structure with a hollow middle part, and the shell jacket of the welding head is a cooling water cavity. The upper end of the cooling water cavity is provided with a cooling water inlet pipe connected to the outside, and the bottom of the cooling water cavity is provided with a ring-shaped cooling water nozzle 3 with an inner diameter of 2mm and a water flow rate of 4m / s, covering the outer area of ​​the arc. The heat dissipation power is ≥2kW, and the nozzle surface is coated with a high-emissivity ceramic coating to enhance radiation heat dissipation. An annular mounting groove is provided on the inner wall corresponding to the rotating seat in the inner cavity of the welding head.

[0007] Optionally, a ring-shaped unidirectional inclined connecting pipe is connected between the upper end of the shielding gas injection sleeve and the shielding gas uniform distribution ring. An argon-hydrogen mixed gas inlet pipe is provided on the shielding gas uniform distribution ring. A ring wheel is rotatably installed in the inner cavity of the shielding gas injection sleeve below the connecting pipe. The ring wheel is composed of a number of unidirectional consistent blades. The connecting pipe sprays gas to the ring wheel. The ring wheel rotates. Vertical rectifying fins with uniform intervals are distributed in an annular manner in the shielding gas injection sleeve below the ring wheel. The rectifying fins guide the gas to flow downward evenly. A guide ring skirt is provided at the lower end of the inner cavity of the shielding gas injection sleeve. The guide ring skirt makes the space at the lower end of the shielding gas injection sleeve wider at the top and narrower at the bottom. An air curtain guide plate 302 is provided in an annular manner on one side of the lower end outlet of the shielding gas injection sleeve close to the welding head. The air curtain flow rate is 10m / s to form a laminar barrier.

[0008] Optionally, the high-frequency pulse waveform control module uses a digital signal processor to generate a programmable pulse waveform with a continuously adjustable frequency range of 20-100kHz and a duty cycle adjustment accuracy of ±1%. The pulse peak current and base current are independently controlled. The peak current range is 50-500A for molten pool impact, and the base current range is 10-50A for maintaining arc stability. The arc morphology sensor is based on a high-speed infrared camera and a photodiode array to collect arc length, diameter and light intensity distribution in real time with a sampling frequency of 1MHz. The sampling frequency is fed back to the DSP to achieve closed-loop control. When arc scattering is detected, the standard deviation of the light intensity distribution is greater than 5%, and the pulse frequency is automatically increased to an upper limit of 100kHz to enhance arc focusing.

[0009] Optionally, a hanger is provided downward on the outer side wall of the protective gas injection sleeve, and a visual sensor assembly is installed at the end of the hanger. The visual sensor assembly consists of a CCD camera and a line laser scanner to identify the workpiece contour and obtain the three-dimensional coordinates of the weld groove in real time. The AI ​​algorithm module trains the weld trajectory prediction model based on the convolutional neural network. The input parameters include the workpiece thickness, groove angle, and thermal deformation, and the welding path compensation value is output.

[0010] Optionally, the main electrode is made of tungsten-rhenium alloy with a diameter of 3 mm. The lower end of the main electrode has a tip cone angle of 30° to improve the arc focusing ability. The surface iridium plating layer is 2 μm thick to reduce the electron escape work function and reduce the arc starting voltage. The cooling structure of the main electrode is 36 microchannels processed axially inside the electrode, which are distributed in a hexagonal array. The coolant is a 50% ethylene glycol aqueous solution and circulates at a flow rate of 0.5-5 L / min. The middle of the uppermost end of the main electrode is connected outwardly with a coolant inlet and outlet pipe connected to the microchannel. A spline gear is provided at a position corresponding to the axial adjustment frame on the main electrode. A lifting thread is provided on the outer wall of the main electrode below the spline gear and is vertically connected to the electrode seat. An upper and lower docking rings are rotatably connected to the outer wall of the main electrode below the electrode seat. The inner cavities of the two docking rings are respectively connected to the inlet and outlet channels of the microchannel. A third gear is fixedly installed on the outer wall of the main electrode below the rotating seat.

[0011] Optionally, an axial adjustment motor is invertedly installed on the axial adjustment frame, and a first gear is fixedly connected to the lower end of the rotating shaft of the axial adjustment motor. The first gear is meshed with the spline gear. When the first gear rotates to drive the spline gear to rotate, the main electrode moves vertically on the electrode holder through the lifting thread, and the distance between the tip of the main electrode and the workpiece is adjusted.

[0012] Optionally, end wheels are rotatably installed at both ends of the rotating seat, and the end wheels are against the wall of the embedded groove. The end wheel at one end is vertically slidably connected to the corresponding end surface of the rotating seat through two buffer rods, and a spring is mounted on the buffer rod.

[0013] Optionally, the auxiliary electrode is made of copper-chromium-zirconium alloy with a diameter of 8 mm. The upper end of the auxiliary electrode passes through the rotating seat and is rotatably connected to the rotating shaft of the servo motor. The servo motor is fixed on the rotating seat. The lower end face of the auxiliary electrode is a groove to form an eddy current effect to evenly disperse the arc. A second gear meshing with the third gear is fixed on the auxiliary electrode under the rotating seat. The auxiliary electrode rotates about the rotation axis of the main electrode, and the eddy current effect of the groove makes the arc evenly distributed in the annular area to avoid local overheating of the main electrode.

[0014] Optionally, the cooling structure of the secondary electrode is a cooling protective sleeve, which is wrapped around the outside of the secondary electrode. The upper end of the cooling protective sleeve is fixedly connected to the rotating seat through two front and rear connecting arms. A spiral groove that can form turbulence is provided in the cavity of the cooling protective sleeve. A cooling circulation pipe is respectively provided in the two connecting arms. The two cooling circulation pipes are respectively connected to the two docking rings on the main electrode for circulating the coolant in the cooling protective sleeve to enhance the heat exchange efficiency.

[0015] The present invention provides a metal fitting plasma welding device, which has the following beneficial effects:

[0016] The high-frequency pulse plasma modulation power supply system, whose high-frequency pulse waveform control module uses a digital signal processor to generate a pulse waveform with a continuously adjustable frequency of 20-100kHz and a duty cycle adjustment accuracy of ±1%, independently controls the peak current of 50-500A to impact the molten pool and the base current of 10-50A to maintain arc stability. The arc shape sensor at the exit is based on a high-speed infrared camera and a photodiode array. The 1MHz sampling frequency collects data in real time and feeds back to the DSP to achieve closed-loop control. When arc scattering (light intensity distribution standard deviation>5%) is detected, the pulse frequency is automatically increased to 100kHz to enhance arc focusing, successfully increasing the penetration depth of 6061 aluminum alloy welding by 33%, reducing the arc stability from voltage fluctuation of ±5V to ±1V, narrowing the width of the heat-affected zone to 0.8mm, and reducing the burn-through rate of thin plate welding to 0.3%.

[0017] In the multi-dimensional collaborative cooling module, the welding head is hollow in the middle, the jacket is a cooling water cavity, the upper end is connected to the cooling water inlet pipe, and the bottom ring is distributed with a cooling water nozzle with an inner diameter of 2mm, a water flow rate of 4m / s, a heat dissipation power ≥2kW, and a surface coated with a high-emissivity ceramic coating to enhance heat dissipation, which effectively reduces the temperature of the welding area. The shielding gas uniform distribution ring inputs the mixed gas through the argon-hydrogen mixed gas inlet pipe, drives the ring wheel to rotate through the one-way inclined connecting pipe, and then guides the shielding gas uniform distribution ring to flow evenly downward. Through the guide ring skirt and the 45° angle air curtain guide plate, a laminar barrier is formed with an air curtain flow rate of 10m / s to protect the welding area from external interference.

[0018] The dual-stage rotating electrode and adaptive cooling system, the main electrode is made of tungsten-rhenium alloy, with a diameter of 3mm, a 30° cone angle tip at the lower end and a 2μm iridium coating on the surface to improve arc focusing and reduce starting voltage, 36 hexagonal arrays of microchannels are distributed inside, and 50% ethylene glycol aqueous solution coolant with a flow rate of 0.5-5L / min is circulated for cooling. The axial adjustment frame adjusts the position of the main electrode through motors, gears and threaded structures. The secondary electrode is made of copper-chromium-zirconium alloy with a diameter of 8mm. The groove at the lower end forms an eddy current effect to evenly disperse the arc. The main electrode rotates with the main electrode rotating axis through gear meshing to avoid local overheating of the main electrode. The cooling protective sleeve strengthens heat exchange through a spiral groove structure and a cooling circulation pipe connected to the main electrode docking ring. Temperature monitoring and secondary cooling and alarm mechanisms ensure stable operation of the electrode, extending the electrode life by 200%, and the temperature rise is stabilized at 45°C at a current of 300A.

[0019] The intelligent weld tracking system is a visual sensor combination installed at the end of the boom on the outer wall of the protective gas injection sleeve. It consists of a CCD camera and a line laser scanner to obtain weld information in real time. The AI ​​algorithm module is based on the convolutional neural network training model, inputs the workpiece parameters and outputs the welding path compensation value. When the assembly gap is detected to be greater than 0.3mm, it automatically adjusts the pulse current and gas flow to prevent the molten pool from collapsing. The auxiliary electrode rotation speed is synchronously matched with the welding speed to ensure uniform distribution of the arc, reducing the welding deformation by 42%, increasing the weld centering qualification rate of complex curved workpieces to 98%, and increasing the welding qualification rate from 85% to 98%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings of the embodiment are briefly introduced below.

[0021] The drawings described below are only related to some embodiments of the present invention, but are not intended to limit the present invention.

[0022] In the attached picture:

[0023] Figure 1 A schematic diagram of the first axial view of the present invention is shown;

[0024] Figure 2 A second axial structural schematic diagram of the present invention is shown;

[0025] Figure 3 A schematic diagram of the top view of the structure of the present invention is shown;

[0026] Figure 4 The present invention shows Figure 3 Schematic diagram of the cross-sectional structure at the AA position;

[0027] Figure 5 A schematic diagram of a half-section axial structure of the present invention is shown;

[0028] Figure 6 The present invention shows Figure 5 Middle B is a schematic diagram of the structure of the enlarged part;

[0029] Figure 7 The present invention shows Figure 5 Middle C is a schematic diagram of the structure of the enlarged part;

[0030] Figure 8 The present invention shows Figure 5 D is a schematic diagram of the structure of the enlarged part;

[0031] Fig. 9 It shows a schematic diagram of the axial structure of the ring wheel and the protective gas injection sleeve of the present invention in a state of being separated;

[0032] Fig.10 It shows an axial structural schematic diagram of the electrode holder and the main electrode of the present invention in a state of being separated;

[0033] Fig.11 It shows an axial structural schematic diagram of the state where the docking ring and the main electrode of the present invention are separated;

[0034] Fig.12 The present invention shows Fig.11 Middle E is a schematic diagram of the structure of the enlarged part;

[0035] Fig.13 It shows a schematic diagram of the axial structure of the cooling protection jacket shell in a half-section state of the present invention;

[0036] Fig.14 The schematic diagram of the lower axial structure of the auxiliary electrode part of the present invention is shown.

[0037] Reference numerals list

[0038] 1. Welding head; 101. Cooling water cavity; 102. Cooling water inlet pipe; 103. Cooling water nozzle; 104. Mounting groove;

[0039] 2. High-frequency pulse waveform control module;

[0040] 3. Protective gas injection sleeve; 301. Guide ring skirt; 302. Air curtain guide plate; 303. Ring wheel; 304. Rectifying fin;

[0041] 4. Protective gas uniform distribution ring; 401. Connecting pipe;

[0042] 5. boom; 501. visual sensor assembly;

[0043] 6. Electrode holder;

[0044] 7. Main electrode; 701. Tip; 702. Coolant inlet and outlet pipes; 703. Spline gear; 704. Lifting thread; 705. Docking ring; 706. Microchannel; 707. Third gear;

[0045] 8. Axial adjustment frame; 801. Axial adjustment motor; 802. First gear;

[0046] 9. Arc-starting gas inlet pipe;

[0047] 10. Rotating seat; 1001. End wheel; 1002. Buffer rod; 1003. Spring;

[0048] 11. auxiliary electrode; 1101. servo motor; 1102. groove; 1103. second gear;

[0049] 12. Cooling protection sleeve; 1201. Connecting arm; 1202. Cooling circulation pipe; 1203. Spiral groove. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Example 1: Please refer to Figures 1 to 14 :

[0052] The present invention proposes a metal fitting plasma welding device, comprising: a high-frequency pulse plasma modulation power supply system, a two-stage rotating electrode, an adaptive cooling system, a multi-dimensional collaborative cooling module and an intelligent weld tracking system, wherein the multi-dimensional collaborative cooling module comprises a welding head 1, a shielding gas injection sleeve 3 and a shielding gas uniform distribution ring 4, the outer annular sheath of the welding head 1 is a shielding gas injection sleeve 3, and a shielding gas uniform distribution ring 4 is arranged above the shielding gas injection sleeve 3; the high-frequency pulse plasma modulation power supply system is composed of a high-frequency pulse waveform control module 2 and an arc shape sensor, the arc shape sensor is installed at the outlet of the welding head 1, and the high-frequency pulse waveform control module 2 is externally hung on the upper end of the outer wall of the shell of the welding head 1; the two-stage rotating electrode is composed of a main electrode 7 and an auxiliary electrode 11, and the cooling structures respectively arranged on the main electrode 7 and the auxiliary electrode 11 constitute an adaptive cooling system, An electrode holder 6 is fixedly installed at the upper end of the cavity of the welding head 1, and the main electrode 7 is fixed on the electrode holder 6. A rotating holder 10 is rotatably installed on the main electrode 7, and an auxiliary electrode 11 is vertically rotatably installed on the rotating holder 10 and rotates with the main electrode 7 as the rotation axis; an axial adjustment frame 8 for adjusting the upper and lower positions of the main electrode 7 is provided on the welding head 1 above the electrode holder 6, and an arc-starting gas inlet pipe 9 for introducing arc-starting gas is provided on the electrode holder 6; the intelligent weld tracking system is composed of a visual sensor combination and an AI algorithm module. When the weld tracking system detects that the assembly gap is greater than 0.3mm, it automatically reduces the pulse current (by 20%) and increases the gas flow (by 30%) to prevent the molten pool from collapsing, and the rotation speed of the auxiliary electrode 11 is synchronously matched with the welding speed: when the welding speed is 1m / min, the rotation speed of the auxiliary electrode 11 is set to 100rpm to ensure uniform distribution of the arc.

[0053] Among them, the welding head 1 is a hollow structure in the middle, and the shell jacket of the welding head 1 is a cooling water cavity 101. The upper end of the cooling water cavity 101 is provided with a cooling water inlet pipe 102 connected to the outside, and the bottom of the cooling water cavity 101 is downwardly provided with a ring-shaped cooling water nozzle 103 with an inner diameter of 2mm and a water flow rate of 4m / s, covering the outer area of ​​the arc. The heat dissipation power is ≥2kW, and the nozzle surface is coated with a high-emissivity ceramic coating to enhance radiation heat dissipation. An annular embedding groove 104 is provided on the inner wall corresponding to the rotating seat 10 in the inner cavity of the welding head 1.

[0054] Among them, a ring-shaped unidirectional inclined connecting pipe 401 is connected between the upper end of the shielding gas injection sleeve 3 and the shielding gas uniform distribution ring 4, an argon-hydrogen mixed gas inlet pipe is provided on the shielding gas uniform distribution ring 4, a ring wheel 303 is rotatably installed in the inner cavity of the shielding gas injection sleeve 3 below the connecting pipe 401, and the ring wheel 303 is composed of a number of unidirectional consistent blades. The connecting pipe 401 sprays gas to the ring wheel 303, and the ring wheel 303 rotates. The shielding gas injection sleeve 3 below the ring wheel 303 is annularly distributed with uniformly spaced vertical rectifying fins 304, and the rectifying fins 304 guide the gas to flow downward evenly. A guide ring skirt 301 is provided at the lower end of the inner cavity of the shielding gas injection sleeve 3. The guide ring skirt 301 makes the lower end space of the shielding gas injection sleeve 3 wide at the top and narrow at the bottom. An air curtain guide plate 302 with an angle of 45° to the welding direction is provided in an annular manner on one side of the lower end outlet of the shielding gas injection sleeve 3 close to the welding head 1. The air curtain flow rate is 10m / s, forming a laminar barrier.

[0055] Among them, the high-frequency pulse waveform control module 2 uses a digital signal processor to generate a programmable pulse waveform, with a frequency range of 20-100kHz continuously adjustable, a duty cycle adjustment accuracy of ±1%, and independent control of the pulse peak current and base current. The peak current range is 50-500A for molten pool impact, and the base current range is 10-50A for maintaining arc stability. The arc shape sensor is based on a high-speed infrared camera and a photodiode array to collect arc length, diameter and light intensity distribution in real time. The sampling frequency is 1MHz and is fed back to the DSP to achieve closed-loop control. When arc scattering is detected, the standard deviation of the light intensity distribution is greater than 5%, and the pulse frequency is automatically increased to the upper limit of 100kHz to enhance arc focusing. When welding 6061 aluminum alloy, the penetration depth is increased from 1.2mm of traditional DC to 1.6mm (an increase of 33%), the arc stability (voltage fluctuation) is reduced from ±5V to ±1V, the width of the heat-affected zone is narrowed from 1.5mm to 0.8mm, and the welding burn-through rate of thin plates (0.5mm) is reduced from 15% to 0.3%.

[0056] Among them, the outer side wall of the protective gas injection sleeve 3 is downwardly provided with a hanger 5, and the end of the hanger 5 is hoisted with a visual sensor assembly 501, which is composed of a CCD camera and a line laser scanner to identify the workpiece contour and obtain the three-dimensional coordinates of the weld groove in real time. The AI ​​algorithm module trains the weld trajectory prediction model based on the convolutional neural network. The input parameters include the workpiece thickness, groove angle, and thermal deformation. The welding path compensation value is output. The welding deformation is reduced from 1.2mm in the traditional process to 0.7mm (a decrease of 42%), and the weld alignment pass rate of complex curved workpieces (such as automobile fuel tank flanges) is increased from 75% to 98%.

[0057] Among them, the axial adjustment motor 801 is invertedly installed on the axial adjustment frame 8, and the lower end of the rotating shaft of the axial adjustment motor 801 is fixedly connected with the first gear 802, and the first gear 802 is meshed with the spline gear 703. When the first gear 802 rotates to drive the spline gear 703 to rotate, the main electrode 7 moves vertically on the electrode holder 6 through the lifting thread 704, and the distance between the tip 701 of the main electrode 7 and the workpiece is adjusted.

[0058] Among them, the two ends of the rotating seat 10 are respectively rotatably installed with end wheels 1001, and the end wheels 1001 are against the groove wall of the embedding groove 104. The end wheel 1001 at one end is vertically slidably connected with the corresponding end surface of the rotating seat 10 through two buffer rods 1002, and the buffer rod 1002 is equipped with a spring 1003.

[0059] Among them, the auxiliary electrode 11 is made of copper-chromium-zirconium alloy with a diameter of 8 mm. The upper end of the auxiliary electrode 11 passes through the rotating seat 10 and is rotatably connected to the rotating shaft of the servo motor 1101. The servo motor 1101 is fixed on the rotating seat 10. The lower end surface of the auxiliary electrode 11 is a groove 1102 to form an eddy current effect to evenly disperse the arc. A second gear 1103 meshing with the third gear 707 is fixed on the auxiliary electrode 11 under the rotating seat 10. The auxiliary electrode 11 rotates around the rotation axis of the main electrode 7, and the eddy current effect of the groove 1102 makes the arc evenly distributed in the annular area to avoid local overheating of the main electrode 7.

[0060] Embodiment 2, on the basis of embodiment 1, the main electrode 7 is made of tungsten-rhenium alloy, with a diameter of 3 mm, the lower end of the main electrode 7 is a tip 701 with a cone angle of 30° to improve the arc focusing ability, the surface is plated with an iridium layer with a thickness of 2 μm to reduce the electron work function and reduce the arc starting voltage, the cooling structure of the main electrode 7 is 36 microchannels 706 processed along the axial direction inside the electrode, distributed in a hexagonal array, the coolant is a 50% ethylene glycol aqueous solution and circulates at a flow rate of 0.5-5 L / min, and the middle of the uppermost end of the main electrode 7 is connected outwardly There is a coolant inlet and outlet pipe 702 communicating with the microchannel 706, a spline gear 703 is provided at a position on the main electrode 7 corresponding to the axial adjustment frame 8, a lifting thread 704 is provided on the outer wall of the main electrode 7 below the spline gear 703 and is connected to the electrode holder 6 for vertical rotation, and two upper and lower docking rings 705 are rotatably connected to the outer wall of the main electrode 7 below the electrode holder 6, and the inner cavities of the two docking rings 705 are respectively connected to the inlet and outlet channels of the microchannel 706, and a third gear 707 is fixedly installed on the outer wall of the main electrode 7 below the rotating seat 10. The cooling structure of the auxiliary electrode 11 is a cooling protective sleeve 12, which is wrapped around the outside of the auxiliary electrode 11. The upper end of the cooling protective sleeve 12 is fixedly connected to the rotating seat 10 through two front and rear connecting arms 1201. A spiral groove 1203 that can form turbulence is provided in the cavity of the cooling protective sleeve 12. A cooling circulation pipe 1202 is respectively provided in the two connecting arms 1201. The two cooling circulation pipes 1202 are respectively connected to the two docking rings 705 on the main electrode 7 to circulate the coolant in the cooling protective sleeve 12. Improve heat exchange efficiency. When the temperature is detected to be greater than 800℃, secondary cooling is triggered (the compressor is additionally started to cool the coolant to 5℃). The built-in redundant temperature sensor (PT100, accuracy ±0.5℃) immediately cuts off the power supply and alarms when any sensor is over-temperature (>1000℃). After 8 hours of continuous welding, the wear of the main electrode 7 is less than 0.1mm (the wear of the traditional electrode is greater than 0.3mm). At a current of 300A, the temperature rise of the main electrode 7 and the auxiliary electrode 11 is stable at 45℃ (the temperature rise of the traditional design is greater than 120℃).

[0061] Experimental data:

[0062]

[0063] The working principle of this embodiment:

[0064] When performing plasma welding of metal accessories, first turn on the high-frequency pulse plasma modulation power supply system. The high-frequency pulse waveform control module 2 uses a digital signal processor to generate a programmable pulse waveform, whose frequency is continuously adjustable at 20-100kHz, the duty cycle adjustment accuracy is ±1%, the pulse peak current range is 50-500A for impacting the molten pool, and the base current range is 10-50A to maintain arc stability. The arc shape sensor located at the exit of the welding head 1 is based on a high-speed infrared camera and a photodiode array. It collects data such as arc length, diameter and light intensity distribution in real time at a sampling frequency of 1MHz, and feeds back to the digital signal processor (DSP) to achieve closed-loop control. When arc scattering is detected, that is, the standard deviation of the light intensity distribution is greater than 5%, the pulse frequency is automatically increased to the upper limit of 100kHz to enhance arc focusing.

[0065] The welding head 1 is hollow in the middle, and its jacket is a cooling water cavity 101. The upper end is connected to the outside through a cooling water inlet pipe 102. A cooling water nozzle 103 with an inner diameter of 2 mm is distributed in an annular manner at the bottom. The water flow rate reaches 4 m / s, which can cover the outer area of ​​the arc. The heat dissipation power is ≥ 2 kW, and the nozzle surface is coated with a high-emissivity ceramic coating to enhance radiation heat dissipation. The shielding gas uniform distribution ring 4 inputs argon-hydrogen mixed gas through the argon-hydrogen mixed gas inlet pipe, and the gas enters the shielding gas injection sleeve 3 through the annularly distributed unidirectional inclined connecting pipe 401. The jet airflow of the connecting pipe 401 drives the ring wheel 303 to rotate. The ring wheel 303 is composed of a number of unidirectional consistent blades. Subsequently, the gas is guided by the shielding gas uniform distribution ring 4 to flow evenly downward, and then passes through the guide ring skirt 301 and the air curtain guide plate 302 with an angle of 45° to form a laminar flow barrier with an air curtain flow rate of 10 m / s to protect the welding area.

[0066] The double-stage rotating electrode starts working. The main electrode 7 is made of tungsten-rhenium alloy, with a diameter of 3mm, a cone angle of 30° at the lower tip 701, and a 2μm iridium layer on the surface. Its cooling structure is 36 microchannels 706 distributed in a hexagonal array processed along the axial direction inside. The coolant is a 50% ethylene glycol aqueous solution with a flow rate of 0.5-5L / min, which circulates through the coolant inlet and outlet pipe 702. The axial adjustment motor 801 on the axial adjustment frame 8 rotates, driving the first gear 802 to rotate, and then the spline gear 703 meshing with it rotates. The main electrode 7 moves vertically on the electrode seat 6 through the lifting screw 704 to adjust the distance between the tip 701 and the workpiece. The auxiliary electrode 11 is made of copper-chromium-zirconium alloy with a diameter of 8mm. The upper end is connected to the rotating shaft of the servo motor 1101 on the rotating seat 10. The groove 1102 on the lower end surface can form an eddy current effect to evenly disperse the arc. The auxiliary electrode 11 below the rotating seat 10 is meshed with the third gear 707 on the main electrode 7 through the second gear 1103, so as to realize the rotation with the main electrode 7 as the rotation axis, thereby avoiding local overheating of the main electrode 7. The cooling structure of the auxiliary electrode 11 is a cooling protective sleeve 12 with a spiral groove 1203, which is connected to the docking ring 705 on the main electrode 7 through the cooling circulation pipe 1202 in the connecting arm 1201 to circulate the coolant. When the temperature is detected to be greater than 800°C, the secondary cooling is triggered, and the built-in redundant temperature sensor monitors in real time. If the temperature is over-temperature, the power supply is immediately cut off and an alarm is given.

[0067] In the intelligent weld tracking system, the visual sensor assembly 501 installed at the end of the outer wall hanger 5 of the protective gas injection sleeve 3 is composed of a CCD camera and a line laser scanner, which can identify the workpiece contour and obtain the three-dimensional coordinates of the weld groove in real time. The AI ​​algorithm module is based on the weld trajectory prediction model trained by the convolutional neural network, inputs parameters such as workpiece thickness, groove angle, thermal deformation, and outputs the welding path compensation value. When the weld tracking system detects that the assembly gap is greater than 0.3mm, it automatically reduces the pulse current by 20% and increases the gas flow by 30% to prevent the molten pool from collapsing. The rotation speed of the auxiliary electrode 11 is synchronously matched with the welding speed. For example, when the welding speed is 1m / min, the rotation speed of the auxiliary electrode 11 is set to 100rpm to ensure uniform distribution of the arc. During the entire welding process, the device of the present invention relies on the coordinated work of various systems to increase the aluminum plate penetration from the traditional 1.2mm to 1.6mm, extend the electrode life from 8 hours to 24 hours, reduce the gas consumption from 12L / min to 5L / min, and increase the welding qualification rate from 85% to 98%.

[0068] In this article, there are a few points to note:

[0069] 1. The drawings of the embodiments of the present invention only involve structures related to the embodiments of the present invention, and other structures can refer to the general design.

[0070] 2. In the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to obtain new embodiments.

[0071] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A plasma welding device for metal parts, characterized in that: include: A high-frequency pulse plasma modulation power supply system, a two-stage rotating electrode, an adaptive cooling system, a multi-dimensional collaborative cooling module and an intelligent weld tracking system. The multi-dimensional collaborative cooling module comprises a welding head (1), a protective gas injection sleeve (3) and a protective gas uniform distribution ring (4). The outer annular sheath of the welding head (1) is a protective gas injection sleeve (3), and a protective gas uniform distribution ring (4) is arranged above the protective gas injection sleeve (3). The high-frequency pulse plasma modulation power supply system comprises a high-frequency pulse waveform control module (2) and an arc shape sensor. The arc shape sensor is installed at the outlet of the welding head (1). The high-frequency pulse waveform control module (2) is externally mounted on the upper end of the outer wall of the shell of the welding head (1). The two-stage rotating electrode is composed of a main electrode (7) and an auxiliary electrode (11), and the cooling structures respectively provided on the main electrode (7) and the auxiliary electrode (11) constitute an adaptive cooling system. The electrode holder (6) is fixedly installed at the upper end of the cavity of the welding head (1), the main electrode (7) is fixed on the electrode holder (6), the rotating seat (10) is rotatably installed on the main electrode (7), and the auxiliary electrode (11) is vertically rotatably installed on the rotating seat (10) and rotates with the main electrode (7) as the rotation axis; the welding head (1) above the electrode holder (6) is provided with an axial adjustment frame (8) for adjusting the upper and lower positions of the main electrode (7); the intelligent weld tracking system is composed of a visual sensor combination and an AI algorithm module.

2. A metal fitting plasma welding device according to claim 1, characterized in that: The welding head (1) is a structure with a hollow center. The shell jacket of the welding head (1) contains a cooling water cavity (101). The upper end of the cooling water cavity (101) is provided with a cooling water inlet pipe (102) connected to the outside. The bottom of the cooling water cavity (101) is provided with annularly distributed cooling water nozzles (103) with an inner diameter of 2 mm and a water flow rate of 4 m / s, covering the peripheral area of ​​the arc. The heat dissipation power is ≥2 kW. The nozzle surface is coated with a high-emissivity ceramic coating to enhance radiation heat dissipation. An annular mounting groove (104) is provided on the inner wall of the inner cavity of the welding head (1) corresponding to the rotating seat (10).

3. A metal fitting plasma welding device according to claim 1, characterized in that: An annularly distributed unidirectionally inclined connecting pipe (401) is connected between the upper end of the protective gas spray sleeve (3) and the protective gas uniform distribution ring (4). An argon-hydrogen mixed gas inlet pipe is provided on the protective gas uniform distribution ring (4). A ring wheel (303) is rotatably installed in the inner cavity of the protective gas spray sleeve (3) below the connecting pipe (401). The ring wheel (303) is composed of a plurality of unidirectional consistent blades. The connecting pipe (401) sprays gas flow onto the ring wheel (303). The ring wheel (303) rotates, and the protective gas below the ring wheel (303) is sprayed. The injection sleeve (3) is provided with evenly spaced vertical rectifying fins (304) in an annular manner. The rectifying fins (304) guide the gas to flow evenly downward. The lower end of the inner cavity of the protective gas injection sleeve (3) is provided with a guide ring skirt (301). The guide ring skirt (301) makes the lower end space of the protective gas injection sleeve (3) wider at the top and narrower at the bottom. The lower end outlet of the protective gas injection sleeve (3) is provided with an air curtain guide plate (302) at an angle of 45° to the welding direction on one side close to the welding head (1). The air curtain flow rate is 10 m / s, forming a laminar barrier.

4. A metal fitting plasma welding device according to claim 1, characterized in that: The high-frequency pulse waveform control module (2) uses a digital signal processor to generate a programmable pulse waveform, with a frequency range of 20-100kHz continuously adjustable, a duty cycle adjustment accuracy of ±1%, and independent control of the pulse peak current and base current. The peak current range is 50-500A for molten pool impact, and the base current range is 10-50A for maintaining arc stability. The arc shape sensor is based on a high-speed infrared camera and a photodiode array, and collects arc length, diameter and light intensity distribution in real time. The sampling frequency is 1MHz, and the feedback is sent to the DSP to realize closed-loop control. When arc scattering is detected, the standard deviation of the light intensity distribution is greater than 5%, and the pulse frequency is automatically increased to an upper limit of 100kHz to enhance arc focusing.

5. The metal fitting plasma welding device according to claim 1, characterized in that: The outer side wall of the protective gas injection sleeve (3) is provided with a suspension rod (5) downward, and a visual sensor assembly (501) is installed at the end of the suspension rod (5). The visual sensor assembly (501) is composed of a CCD camera and a line laser scanner, and is used to identify the contour of a workpiece and obtain the three-dimensional coordinates of the weld groove in real time. The AI ​​algorithm module trains a weld trajectory prediction model based on a convolutional neural network, and inputs parameters including workpiece thickness, groove angle, and thermal deformation, and outputs a welding path compensation value.

6. The metal fitting plasma welding device according to claim 1, characterized in that: The main electrode (7) is made of tungsten-rhenium alloy and has a diameter of 3 mm. The lower end of the main electrode (7) is a tip (701) with a cone angle of 30° to improve the arc focusing ability. The surface is plated with an iridium layer with a thickness of 2 μm to reduce the electron work function and reduce the arc starting voltage. The cooling structure of the main electrode (7) is 36 microchannels (706) processed along the axial direction inside the electrode and distributed in a hexagonal array. The coolant is a 50% ethylene glycol aqueous solution and circulates at a flow rate of 0.5-5 L / min. The middle of the uppermost end of the main electrode (7) is connected to the outside with a coolant inlet and outlet pipe that communicates with the microchannel (706). (702), a spline gear (703) is provided at a position on the main electrode (7) corresponding to the axial adjustment frame (8), a lifting thread (704) is provided on the outer wall of the main electrode (7) below the spline gear (703) and is vertically rotatably connected to the electrode seat (6), and two upper and lower docking rings (705) are rotatably connected to the outer wall of the main electrode (7) below the electrode seat (6), and the inner cavities of the two docking rings (705) are respectively connected to the inlet and outlet channels of the microchannel (706), and a third gear (707) is fixedly installed on the outer wall of the main electrode (7) below the rotating seat (10).

7. A metal fitting plasma welding device according to claim 6, characterized in that: An axial adjustment motor (801) is invertedly mounted on the axial adjustment frame (8); a first gear (802) is fixedly connected to the lower end of the rotating shaft of the axial adjustment motor (801); the first gear (802) is meshed with a spline gear (703); when the first gear (802) rotates to drive the spline gear (703) to rotate, the main electrode (7) moves vertically on the electrode holder (6) via the lifting thread (704), and the distance between the tip (701) of the main electrode (7) and the workpiece is adjusted.

8. The metal fitting plasma welding device according to claim 1, characterized in that: The auxiliary electrode (11) is made of copper-chromium-zirconium alloy and has a diameter of 8 mm. The upper end of the auxiliary electrode (11) passes through the rotating seat (10) and is rotatably connected to the rotating shaft of the servo motor (1101). The servo motor (1101) is fixed on the rotating seat (10). The lower end surface of the auxiliary electrode (11) is a groove (1102) that forms an eddy current effect to evenly disperse the arc. A second gear (1103) that meshes with the third gear (707) is fixed on the auxiliary electrode (11) below the rotating seat (10). The auxiliary electrode (11) rotates around the rotating axis of the main electrode (7). The eddy current effect of the groove (1102) makes the arc evenly distributed in the annular area, thereby avoiding local overheating of the main electrode (7).

9. The metal fitting plasma welding device according to claim 6, characterized in that: The cooling structure of the auxiliary electrode (11) is a cooling protective sleeve (12), which is wrapped around the outside of the auxiliary electrode (11). The upper end of the cooling protective sleeve (12) is fixedly connected to the rotating seat (10) through two front and rear connecting arms (1201). A spiral groove (1203) capable of forming turbulence is provided in the cavity of the cooling protective sleeve (12). A cooling circulation pipe (1202) is respectively provided in the two connecting arms (1201). The two cooling circulation pipes (1202) are respectively connected to two docking rings (705) on the main electrode (7) for circulating the coolant in the cooling protective sleeve (12) to enhance the heat exchange efficiency.

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