Laser directional induction arc discharge milling system and method

Abstract

The invention discloses a laser directional induction arc discharge milling processing system and a laser directional induction arc discharge milling processing method. According to the method, laser is used for puncturing air to directionally trigger arc combustion to efficiently remove materials, meanwhile, air jet flow under a large discharge gap is used for effective arc breaking, continuous arcs are prevented from burning a workpiece, and the conductive performance of the workpiece does not need to be considered; the arc plasma motion trail is copied on a workpiece to form a specific complex contour, and therefore the efficient and high-precision machining method for the high-performance material complex part characteristics is achieved.

Description

Technical Field

[0001] The invention particularly relates to a laser directional induced arc discharge milling processing system and a processing method, belonging to the technical field of special processing. Background Art

[0002] A large number of high-performance materials are used in the manufacturing process of the aviation industry, such as nickel-based alloys, titanium alloys, metal-based composites, ceramic-based composites, etc. These materials usually have comprehensive properties such as high hardness, high strength, high temperature resistance, and corrosion resistance. As the performance of aircraft improves, the performance of materials is also constantly improving. For some large structural parts or pressure vessels, such as connection frames and casings, the material removal rate is very high, which brings huge challenges to the traditional processing industry.

[0003] When dealing with these high-performance materials, traditional mechanical processing has a strong cutting force that causes serious tool wear. For hard and brittle materials, internal defects will also occur during the processing. Laser processing, EDM, arc processing, electrolytic processing, etc. in special processing have no obvious contact stress and rely on thermal energy or electrochemical energy to remove materials. They have their own specific advantages and applications. Macro laser processing uses a high-energy-density laser beam to irradiate the surface of the material, causing the material to ablate, melt, and evaporate. It has high processing efficiency, but the heat-affected zone is large, and the energy gradually decays when penetrating a thicker workpiece, and the processing depth is uneven. EDM has high precision and can completely replicate complex electrode shapes or motion trajectories on the workpiece to form a specific contour, and the heat-affected zone is controllable, but its processing efficiency is low and there is electrode loss. Arc processing, as a derivative process of EDM, significantly improves the efficiency of discharge processing, but the switching time of the arc needs to be strictly controlled, otherwise it is easy to cause continuous arc burns to the workpiece, resulting in a significant recast layer and heat-affected zone. Electrolytic machining has no obvious thermal stress, so the surface quality of the machining is very high, but the flow field must be strictly controlled and the dielectric conductivity must be kept constant, otherwise uneven dissolution will damage the machining accuracy. In addition, EDM, arc machining and electrolytic machining all require that the material is conductive. For non-conductive or weakly conductive materials, such as ceramic-based composites, the machining limitations are high. Summary of the invention

[0004] In view of the characteristics of complex components made of high-performance materials, the main purpose of the present invention is to provide a laser directional induced arc discharge milling system and processing method. This technology does not need to consider the strength, hardness, conductivity and other characteristics of the material, has a wide range of applications, and has strong engineering application value, thereby overcoming the shortcomings of the prior art.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: A first aspect of an embodiment of the present invention provides a laser directional induced arc discharge milling system, which includes a milling unit, wherein the milling unit includes: An arc generating module, the arc generating module comprising an electrode pair, the electrode pair comprising two discharge electrodes arranged at intervals, the narrowest width of the gap between the two discharge electrodes being greater than the air discharge gap distance; An air jet module, the air jet module is at least used to provide an air jet, the air jet flows through the gap between the two discharge electrodes; A laser module, wherein the laser module is used to provide a pulsed laser and converge the pulsed laser on a gap between the two discharge electrodes, and focus the pulsed laser between the two discharge electrodes. At the focal position of the pulsed laser, the compressed air contained in the air jet contacts the pulsed laser and undergoes optical breakdown and ionization to generate plasma. When the discharge electrode is connected to a power source, the plasma induces arc plasma between the two discharge electrodes. The arc plasma is directionally twisted toward a workpiece to be processed under the impact of the air jet, and the power density of the arc plasma is greater than the ablation threshold of the workpiece material to be processed.

[0006] A second aspect of an embodiment of the present invention provides a laser directional induced arc discharge milling method, which comprises: Power is supplied to two discharge electrodes of the electrode pair by a power source, the two discharge electrodes are arranged at an interval, and the narrowest width of the gap between the two discharge electrodes is larger than the air discharge gap distance, and air jet and pulse laser are provided, and the air jet flows through the gap between the two discharge electrodes, the pulse laser is converged in the gap between the two discharge electrodes, and the pulse laser is focused between the two discharge electrodes; At the focal position of the pulse laser, the compressed air contained in the air jet contacts the pulse laser and undergoes optical breakdown and ionization to generate plasma, and the plasma induces arc plasma between the two discharge electrodes. The arc plasma is directionally twisted toward a workpiece to be processed under the impact of the air jet and contacts the workpiece to be processed. The power density of the arc plasma is greater than the ablation threshold of the material of the workpiece to be processed, and a part of the workpiece to be processed is ablated and removed, thereby achieving processing of the workpiece to be processed.

[0007] Compared with the prior art, the advantages of the present invention include: A laser directional induced arc discharge milling processing system and processing method provided in an embodiment of the present invention utilizes a high-power pulse laser focus in combination with compressed air to generate arc plasma in a timed and directional manner in a discharge electrode gap exceeding a discharge distance, thereby improving the control accuracy of DC arc plasma.

[0008] The embodiment of the present invention provides a laser directional induced arc discharge milling processing system and processing method, which utilizes the plasma generated by air breakdown to absorb laser energy to induce arc plasma. The arc plasma absorbs the laser energy before the residual pulse is shut down, has high adaptive shielding, and can reduce the damage of the laser to the processing surface.

[0009] The embodiments of the present invention provide a laser directional induced arc discharge milling processing system and processing method. A compressed air jet impacts and distorts the arc column in a wide discharge gap, which has a higher arc breaking efficiency, can prevent the generation of continuous arcs, and reduce thermal damage to the workpiece. Combined with a CNC system for layer-by-layer milling, the processing accuracy is higher.

[0010] The embodiment of the present invention provides a laser directional induced arc discharge milling processing system and processing method, the center temperature of the arc column zone can reach up to tens of thousands of degrees Celsius, which can make the workpiece material melt and gasify quickly, and the material removal rate is high.

[0011] The embodiment of the present invention provides a laser directional induced arc discharge milling processing system and processing method. Since the workpiece does not serve as a current loop link, there is no need to consider the conductive properties of the workpiece material, only the heat transfer properties of the workpiece need to be considered, which means that this technology can achieve efficient processing of non-conductive materials.

[0012] The embodiment of the present invention provides a laser directional induced arc discharge milling processing system and processing method. The processing technology cooperates with multi-axis linkage and CAM software to copy the arc plasma motion trajectory on the workpiece to form a specific contour, thereby realizing complex surface or contour processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of a laser directional induced arc discharge milling system provided in a typical implementation case of the present invention; Figure 2 It is a principle diagram of a laser directional induced arc discharge milling method provided in a typical implementation case of the present invention; Figure 3 It is a schematic diagram of a single arc triggering, burning and shutting-off process in a laser directional induced arc discharge milling process provided in a typical implementation case of the present invention; Figure 4 It is a real-time matching diagram of laser power and arc discharge waveform. DETAILED DESCRIPTION

[0014] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

[0015] The present invention utilizes laser to penetrate the air to trigger arc combustion to efficiently remove materials, and at the same time uses the air jet under the large discharge gap to effectively break the arc, thereby preventing continuous arc from burning the workpiece. There is no need to consider the conductive properties of the workpiece. By cooperating with a multi-axis motion platform, the arc plasma motion trajectory is replicated on the workpiece to form a specific complex contour. This method is suitable for efficient and high-precision processing of complex component features of high-performance materials.

[0016] The present invention utilizes a high-power laser focus to break down compressed air between discharge electrodes exceeding a discharge gap to form plasma. The electron density inside the plasma is very high, which reduces the air breakdown threshold between the two electrodes, causing an arc to be generated near the focus between the discharge electrodes and burning. Subsequently, the laser is in a pulse interval and cannot continue to generate plasma, and a nozzle coaxial with the laser sprays compressed air to continuously flush the arc plasma to twist it to the surface of the workpiece to achieve efficient material removal. Since the discharge electrode gap is wide, the arc column is broken by the air jet before the next laser-induced plasma occurs, completing an arc extinguishing operation.

[0017] The present invention triggers arc discharge through a high-power laser and uses air jet to make the arc burn in a directed manner. Since the gap between the discharge electrodes is wide and the power supply is not connected to the workpiece, the workpiece will not be burned by the continuous arc, and there is no need to consider the conductivity of the workpiece. In conjunction with the electrode compensation device in the processing system, long-term continuous processing can be achieved, and combined with five-axis linkage, efficient processing of complex surfaces and cavities can be achieved.

[0018] A first aspect of an embodiment of the present invention provides a laser directional induced arc discharge milling system, which includes a milling unit, wherein the milling unit includes: An arc generating module, the arc generating module comprising an electrode pair, the electrode pair comprising two discharge electrodes arranged at intervals, the narrowest width of the gap between the two discharge electrodes being greater than the air discharge gap distance; An air jet module, the air jet module is at least used to provide an air jet, the air jet flows through the gap between the two discharge electrodes; A laser module, wherein the laser module is used to provide a pulsed laser and converge the pulsed laser on a gap between the two discharge electrodes, and focus the pulsed laser between the two discharge electrodes. At the focal position of the pulsed laser, the compressed air contained in the air jet contacts the pulsed laser and undergoes optical breakdown and ionization to generate plasma. When the discharge electrode is connected to a power source, the plasma induces arc plasma between the two discharge electrodes. The arc plasma is directionally twisted toward a workpiece to be processed under the impact of the air jet, and the power density of the arc plasma is greater than the ablation threshold of the workpiece material to be processed.

[0019] Furthermore, the optical axis of the focused pulse laser, the central axis of the air jet, and the central axis of the gap between the two discharge electrodes coincide with each other.

[0020] Furthermore, the two discharge electrodes are arranged in mirror symmetry, and the optical axis of the pulsed laser, the central axis of the air jet, and the symmetry axes of the two discharge electrodes coincide with each other.

[0021] In a more specific embodiment, the air jet module includes an air compressor and a nozzle, and the air compressor is connected to the nozzle; The laser module comprises a laser, other optical path components and a focusing lens, wherein the other optical path components are used to guide the pulse laser emitted by the laser to the focusing lens, and the focusing lens is used to focus the pulse laser on the gap between the two discharge electrodes; The nozzle is located between the focusing lens and the electrode pair, and the outlet of the nozzle faces the gap between the electrode pair.

[0022] Furthermore, the arc generating module also includes a power supply, and the power supply is electrically connected to the electrode pair.

[0023] Furthermore, the power supply includes a direct current power supply.

[0024] Furthermore, the laser is a high-power millisecond laser.

[0025] Furthermore, the other optical path components include optical elements such as dichroic mirrors.

[0026] In a more specific embodiment, the laser module further includes a positioning detection mechanism, and the positioning detection mechanism is used to locate the trajectory of the pulsed laser.

[0027] Furthermore, the positioning detection mechanism includes a CCD camera, which emits a visible light beam, and the visible light beam passes through other optical path components and a focusing lens to form a positioning light beam with the same optical axis as the pulse laser.

[0028] In a more specific embodiment, the discharge electrodes are arranged obliquely, and the distance between the two discharge electrodes gradually decreases along the flow direction of the air jet.

[0029] Furthermore, the narrowest distance between the two discharge electrodes is 1 mm to 3 mm.

[0030] In a more specific implementation, the laser directional induced arc discharge milling system further includes: an electrode compensation module, and the electrode compensation module is used to fix the electrode pair.

[0031] Furthermore, the electrode compensation module includes two groups of electrode assembly racks, and each of the discharge electrodes is assembled on one of the electrode assembly racks.

[0032] Furthermore, the electrode assembly frame includes a brush holder, an electrode track, a support seat, and a stopper, wherein the electrode track is fixedly arranged on the support seat, the discharge electrode is arranged in the electrode track and movably cooperates with the electrode track, the brush holder is fixedly arranged at the end of the electrode track and is electrically connected to the discharge electrode, the stopper is fixedly arranged at the front end of the electrode track, an opening is arranged on the stopper, the end face of the discharge electrode is exposed from the opening, and the narrowest distance is between the ends of the two discharge electrodes close to the stopper.

[0033] Furthermore, the brush holder also has an elastic member, and the elastic member is elastically matched with the discharge electrode.

[0034] In a more specific embodiment, the laser directional induced arc discharge milling system also includes: a motion unit, which is in transmission cooperation with the milling unit and the workpiece to be processed, and is used to drive the milling unit and the workpiece to be processed to produce relative movement to form a specific processing shape on the workpiece to be processed, wherein the relative movement includes relative linear motion along at least one of the x-axis, y-axis, and z-axis of a three-dimensional coordinate system and / or relative rotational motion around at least one of the x-axis, y-axis, and z-axis of a three-dimensional coordinate system.

[0035] Furthermore, the motion unit includes a five-axis motion platform.

[0036] Furthermore, the electrode pair of the arc generating module, the nozzle of the air jet module, other optical path components and the lens of the laser module are installed on the z-axis slide of the five-axis motion platform, the linear module of the z-axis slide is installed on the x-axis slide, and the workpiece to be processed is set on the cradle turntable of the five-axis motion platform.

[0037] In a more specific embodiment, the laser directional induced arc discharge milling system further includes: a current detection unit, which is electrically connected to the arc generating module and is at least used to monitor the machining current; Furthermore, the current detection unit includes an oscilloscope and a current probe, the oscilloscope is electrically connected to the current probe, and the current probe is electrically connected to a wire connecting a power source and the electrode pair.

[0038] A second aspect of an embodiment of the present invention provides a laser directional induced arc discharge milling method, which comprises: Power is supplied to two discharge electrodes of the electrode pair by a power source, the two discharge electrodes are arranged at an interval, and the narrowest width of the gap between the two discharge electrodes is larger than the air discharge gap distance, and air jet and pulse laser are provided, and the air jet flows through the gap between the two discharge electrodes, the pulse laser is converged in the gap between the two discharge electrodes, and the pulse laser is focused between the two discharge electrodes; At the focal position of the pulse laser, the compressed air contained in the air jet contacts the pulse laser and undergoes optical breakdown and ionization to generate plasma, and the plasma induces arc plasma between the two discharge electrodes. The arc plasma is directionally twisted toward a workpiece to be processed under the impact of the air jet and contacts the workpiece to be processed. The power density of the arc plasma is greater than the ablation threshold of the material of the workpiece to be processed, and a part of the workpiece to be processed is ablated and removed, thereby achieving processing of the workpiece to be processed.

[0039] In a more specific embodiment, the laser directional induced arc discharge milling method further includes: causing the arc plasma and the workpiece to be processed to move relative to each other, and replicating the movement trajectory of the arc plasma on the workpiece to be processed to form a specific shape.

[0040] Furthermore, the laser directional induced arc discharge milling processing method is implemented based on the laser directional induced arc discharge milling processing system.

[0041] Furthermore, the material of the workpiece to be processed is a hard and brittle material.

[0042] The technical solution, its implementation process and principles, etc. will be further explained below in conjunction with the accompanying drawings and specific implementation cases. Unless otherwise specified, the lasers, discharge electrodes, focusing lenses and other optical elements, power supplies, computers, water coolers, CCD cameras, air compressors, nozzles, oscilloscopes, control cabinets and five-axis motion platforms used in the embodiments of the present invention are all known in the art and can be purchased commercially. The specific equipment structures, models, etc. are not limited here.

[0043] In a typical implementation case, please refer to Figure 1 A laser directional induced arc discharge milling system includes: a laser 11, a dichroic mirror 14, a focusing lens 1, an air compressor (not shown in the figure), a nozzle 21, two discharge electrodes 4, and a power supply 8. The two discharge electrodes 4 are electrically connected to the power supply 8 respectively, and the two discharge electrodes 4 are arranged at intervals, and the narrowest width of the gap between the two discharge electrodes 4 is greater than the air discharge gap distance; the nozzle 21 is connected to the air compressor, and the nozzle 21 is arranged above the gap between the two discharge electrodes 4. The compressed air provided by the air compressor enters the nozzle 21 and is accelerated to form an air jet 3. The laser 11 is used to provide a high-power pulsed laser beam 2. The dichroic mirror 14 and the focusing lens 1 are arranged in sequence on the optical path of the pulsed laser beam 2. The focusing lens 1 is arranged directly above the nozzle 21. The dichroic mirror 14 reflects the pulsed laser beam 2 to the focusing lens 1. The pulsed laser beam 2 is focused by the focusing lens 1 to form a focused beam. The focused beam passes through the gap between the two discharge electrodes 4, and the focus of the pulsed laser beam 2 is located in the gap between the two discharge electrodes 4. Specifically, the gap between the ends of the two discharge electrodes 4 away from the nozzle 21 has the narrowest width, and the focus of the pulsed laser beam 2 is preferably located near the ends of the two discharge electrodes 4 away from the nozzle 21.

[0044] More specifically, the two discharge electrodes 4 are arranged obliquely, specifically, they are inclined from the end close to the nozzle 21 to the direction close to each other, that is, the spacing between the two discharge electrodes 4 gradually decreases in the direction away from the nozzle 21, and has the narrowest width between the ends away from the nozzle 21. More specifically, the two discharge electrodes 4 are arranged in mirror symmetry, and the symmetry axes of the two discharge electrodes 4, the optical axis of the pulsed laser beam 2 converged by the focusing lens 1, and the central axis of the air jet 3 coincide.

[0045] Specifically, the power supply 8 may be a DC power supply, and the power supply 8 is electrically connected to the two discharge electrodes 4 via a wire. Exemplarily, the narrowest distance between the two discharge electrodes 4 may be 1 mm to 3 mm, and the material of the discharge electrode 4 is high melting point graphite. Specifically, the air compressor is connected to the nozzle 21 via an air pipeline. More specifically, the nozzle 21 and the air pipeline are connected via a quick connector 20, and the compressed air enters the nozzle 21 through the quick connector 20 to accelerate and form an air jet 3 coaxial with the pulse laser beam 2.

[0046] For details, please refer to Figure 2The power supply 8 continuously supplies electric energy to the discharge electrode 4. Since the narrowest distance between the two discharge electrodes 4 is larger than the air discharge gap distance, the two discharge electrodes 4 will not spontaneously generate discharge. The pulsed laser beam 2 focuses on the gap between the two discharge electrodes 4 through the focusing lens 1. The air jet 3 coaxial with the pulsed laser beam 2 flows through the gap between the two discharge electrodes 4. The pulsed laser beam 2 causes the compressed air in the air jet 3 to undergo optical breakdown and ionization at the focus to generate plasma. The plasma induces the two discharge electrodes 4 to generate arc plasma 5. The arc plasma 5 is twisted toward the workpiece 6 and contacts the workpiece 6 under the jet action of the air jet 3. The power density of the arc plasma 5 is larger than the ablation threshold of the workpiece 6 material. The workpiece 6 is partially ablated and removed, thereby achieving directional and efficient removal of the workpiece material, and the melted material forms a processed product 7.

[0047] For details, please refer to Figure 3 , Figure 3 The schematic diagram of the single arc triggering, burning and shutoff process in laser directional induced arc discharge milling processing is shown in FIG. The narrowest distance between the discharge electrodes 4 is slightly larger than the air discharge gap, and no air breakdown occurs. The pulsed laser beam 2 is focused in the gap between the discharge electrodes 4 by the focusing lens 1. When the air jet 3 passes through the gap between the discharge electrodes 4, the energy density of the pulsed laser beam 2 is high, causing optical breakdown and ionization of the air at the focus, generating plasma 26. The electron density inside the plasma 26 is very high. As the plasma 26 diffuses, the air breakdown threshold in the gap between the discharge electrodes 4 decreases. Air breakdown occurs at a distance greater than the discharge gap, generating arc plasma 5. Subsequently, the laser is in a pulse interval, and the air jet 3 continuously acts on the arc plasma 5, causing the arc column to twist and rush toward the workpiece 6. The workpiece material is melted by thermal energy to generate a pit 27. The distance between the pit 27 and the arc plasma 5 increases. Combined with the continuous flushing effect of the air jet 3, the arc column is easily extinguished to complete the arc breaking. In addition, the air jet 3 also discharges the processed product 7 out of the processing area to keep the processed surface clean.

[0048] Specifically, the laser 11 is preferably a high-power millisecond laser, so the duration and shutdown time of a single pulse are in the order of milliseconds. When the pulse of the pulsed laser beam 2 just acts on the air jet 3 in the gap between the discharge electrode 4, a plasma 26 is excited and generated, which gradually expands with the increase of the laser peak power. When the expansion is maintained at the peak power, an arc is instantly started to generate an arc plasma 5, and then the laser power is reduced. During this process, the air jet 3 continues to act on the arc plasma 5 to extend and distort it, resulting in an increase in the internal resistance of the arc, and the current gradually decreases and fluctuates in a small range. When the laser power is 0, the arc is still ablating the workpiece material, and the gap increases after the discharge pit 27 is generated, and the internal resistance of the arc further increases, which is extinguished by the flushing effect of the air jet 3, and the current is 0. The time from the generation to the extinction of the arc is also in the order of milliseconds, so the arc can be adjusted by laser pulses and air jet timing.

[0049] For details, please refer to Figure 1 In order to assemble the discharge electrode, the laser directional induced arc discharge milling system also includes an electrode compensation module, which is used to fix the electrode pair consisting of two discharge electrodes. The electrode compensation module includes two sets of electrode assembly frames, and each discharge electrode is assembled on an electrode assembly frame. More specifically, the electrode assembly frame includes a brush holder 22, an electrode track 25, a support seat 23, and a stopper 24. The discharge electrode 4 is arranged in the electrode track 25 and is movably matched with the electrode track. The electrode track 25 is fixedly arranged on the support seat 23 and supported and fixed by the support seat 23. The brush holder 22 is fixedly arranged at the end (tail) of the electrode track 25 and is electrically connected to the discharge electrode 4. The stopper 24 is fixedly arranged at the front end of the electrode track 25. An opening is arranged on the stopper 24. The size of the opening is slightly smaller than the diameter of the discharge electrode. The end face of the discharge electrode 4 is exposed from the opening. The two discharge electrodes 4 have a narrowest distance between their ends close to the stopper 24. More specifically, the brush holder 22 has an elastic member inside, which continuously pushes the discharge electrode 4 and cooperates with the stopper 24 at the front end to achieve electrode compensation. The power supply 8 is electrically connected to the brush holder 22 and provides electrical energy to the discharge electrode 4 through the brush holder 22 .

[0050] For details, please refer to Figure 1 In order to monitor the machining current of the discharge electrode, the laser directional induced arc discharge milling system also includes a current detection unit, which is electrically connected to the discharge electrode 4 and is at least used to monitor the machining current. Specifically, the current detection unit includes an oscilloscope 15 and a current probe. The oscilloscope 15 is electrically connected to the current probe. The current probe and the power supply 8 are electrically connected to the connecting wires of the two discharge electrodes 4, that is, the oscilloscope 15 is connected to the positive and negative lines of the power supply 8 to monitor the machining current. More specifically, the oscilloscope 15 is also connected to the second computer 16, and the machining current obtained by the oscilloscope 15 is displayed on the screen of the computer 16 to reflect the machining status in real time.

[0051] For details, please refer to Figure 1 In order to calibrate the processing position, the laser directional induced arc discharge milling system also includes a positioning detection mechanism, which is used to locate the trajectory of the pulsed laser beam. Specifically, the positioning detection mechanism includes a CCD camera 12 and a lens 13. The CCD camera 12, the lens 13, the dichroic mirror 14 and the focusing lens 1 are arranged on the same optical axis. The pulsed laser beam 2 emitted by the laser 11 is reflected by the dichroic mirror 14 into the focusing lens 1 to form a focused beam and is incident on the gap of the discharge electrode 4. The CCD camera 12 emits a visible light beam, which passes through the lens 13, the dichroic mirror 14 and the focusing lens 1 in sequence to form a positioning beam. The positioning beam is kept coaxial with the pulsed laser beam to calibrate the processing position.

[0052] For details, please refer to Figure 1 The laser directional induced arc discharge milling system also includes a first computer 9 and a water cooler 10. The first computer 9 is connected to the internal control part of the laser 11 and is used to adjust the laser parameters and switches. The water cooler 10 cooperates with the laser 11 and is used to adjust the temperature of the laser 11 to keep the laser 11 working stably. It should be noted that the first computer 9 and the water cooler 10 are both known in the art, and the numerical control system / software contained in the first computer 9 can also be purchased commercially, and no specific limitation is made here. The water cooler 10 can of course be replaced by other temperature control devices.

[0053] For details, please refer to Figure 1In order to better realize the processing of the structure of the desired shape on the workpiece, the laser directional induced arc discharge milling system also includes a motion processing platform (i.e. the aforementioned motion processing unit), which is at least used to make the arc plasma 5 and the workpiece 6 produce relative motion, and the relative motion includes relative linear motion along at least one of the x-axis, y-axis, and z-axis of a three-dimensional coordinate system and / or relative rotational motion around at least one of the x-axis, y-axis, and z-axis of a three-dimensional coordinate system, so as to realize the processing of a specific shape structure on the workpiece 6. More specifically, the motion processing platform can be a five-axis motion platform, which includes an X-axis slide, a Y-axis slide, a Z-axis slide and a cradle turntable 18. The discharge electrode 4, the nozzle 21, and the focusing lens 1 are all installed on the Z-axis slide 19, so that the laser beam 2, the discharge electrode 4, and the air jet 3 maintain synchronous movement. The Z-axis slide is installed on the X-axis slide, the workpiece 6 is fixed on the cradle turntable 18, and the cradle turntable 18 is installed on the Y-axis slide. The cradle turntable 18 can rotate around the X-axis and Z-axis. The X, Y, and Z linear modules of the X-axis slide, the Y-axis slide, and the Z-axis slide and the cradle platform 18 are all connected to the control cabinet 17 and controlled by the control cabinet 17. The control cabinet 17 is also connected to the second computer 16, and the second computer 16 inputs instructions to control the five-axis motion. The workpiece is fixed on the cradle turntable of the five-axis motion platform to realize the rotation and flipping of the workpiece. The control cabinet 17 is used to realize five-axis linkage of the X, Y, Z, A, and C axes to adapt to more complex contour processing. The control cabinet 17 establishes communication with the second computer 16 and controls the platform movement through code.

[0054] It should be noted that the five-axis motion platform certainly also includes other structures that can realize five-axis motion in addition to the X-axis slide, Y-axis slide, Z-axis slide and cradle turntable 18, which are all known in the art and are not limited to their specific structural composition and the configuration relationship between the various components. The control cabinet 17 and the control system used by the second computer are all known in the art and are not specifically limited here.

[0055] Furthermore, the electrode pair of the arc generating module, the nozzle of the air jet module, other optical path components of the laser module, and the lens are installed on the z-axis slide of the five-axis motion platform, the linear module of the z-axis slide is installed on the x-axis slide, and the workpiece to be processed is set on the cradle turntable of the five-axis motion platform.

[0056] In a typical implementation case, Figure 1 A method for performing milling processing by a laser directional induced arc discharge milling processing system may include the following process: (1) The power supply provides excitation energy for the discharge electrodes. The discharge electrodes are arranged symmetrically, and their narrowest distance slightly exceeds the discharge gap distance to prevent continuous arcing in the narrow gap from burning the workpiece and reducing the arc breaking pressure; (2) Turn on the laser, adjust the laser beam to focus it near the discharge electrode, and turn on the air compressor to generate a coaxial air jet to increase the air density in the processing area. The energy density at the focal position of the high-power laser beam is the highest, where optical breakdown and electron avalanche occur, forming a local plasma; (3) The high electron density of the plasma reduces the air breakdown threshold between the discharge electrodes, achieving arc ignition conditions outside the discharge gap and stimulating arc plasma; (4) After the laser energy is absorbed by the plasma, it is in the pulse off period, but the arc continues to burn. The coaxial air jet rushes towards the arc plasma to twist it downward, and then makes it close to the workpiece to melt the material with the help of heat energy. As the material is eroded, the gap between the workpiece and the plasma increases, and the coaxial air jet breaks the arc plasma, ending the discharge. (5) The laser acts as a trigger switch for the arc, causing the arc to be intermittently generated and shut down, cyclically removing the material. The control system controls the X, Y, Z, A, and C linkages to replicate the arc's motion trajectory on the workpiece to form a specific shape.

[0057] A laser directional induced arc discharge milling processing system and processing method provided in an embodiment of the present invention utilizes a high-power pulse laser focus in combination with compressed air to generate arc plasma in a timed and directional manner in a discharge electrode gap exceeding a discharge distance, thereby improving the control accuracy of DC arc plasma.

[0058] The embodiment of the present invention provides a laser directional induced arc discharge milling processing system and processing method, which utilizes the plasma generated by air breakdown to absorb laser energy to induce arc plasma. The arc plasma absorbs the laser energy before the residual pulse is shut down, has high adaptive shielding, and can reduce the damage of the laser to the processing surface.

[0059] The embodiments of the present invention provide a laser directional induced arc discharge milling processing system and processing method. A compressed air jet impacts and distorts the arc column in a wide discharge gap, which has a higher arc breaking efficiency, can prevent the generation of continuous arcs, and reduce thermal damage to the workpiece. Combined with a CNC system for layer-by-layer milling, the processing accuracy is higher.

[0060] The embodiment of the present invention provides a laser directional induced arc discharge milling processing system and processing method, the center temperature of the arc column zone can reach up to tens of thousands of degrees Celsius, which can make the workpiece material melt and gasify quickly, and the material removal rate is high.

[0061] The embodiment of the present invention provides a laser directional induced arc discharge milling processing system and processing method. Since the workpiece does not serve as a current loop link, there is no need to consider the conductive properties of the workpiece material, only the heat transfer properties of the workpiece need to be considered, which means that this technology can achieve efficient processing of non-conductive materials.

[0062] The embodiment of the present invention provides a laser directional induced arc discharge milling processing system and processing method. The processing technology cooperates with multi-axis linkage and CAM software to copy the arc plasma motion trajectory on the workpiece to form a specific contour, thereby realizing complex surface or contour processing.

[0063] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser directional induced arc discharge milling system, characterized in that: A milling processing unit is included, and the milling processing unit includes: An arc generating module, the arc generating module comprising an electrode pair, the electrode pair comprising two discharge electrodes arranged at intervals, the narrowest width of the gap between the two discharge electrodes being greater than the air discharge gap distance; An air jet module, the air jet module is at least used to provide an air jet, the air jet flows through the gap between the two discharge electrodes; A laser module, wherein the laser module is used to provide a pulsed laser and converge the pulsed laser on a gap between the two discharge electrodes, and focus the pulsed laser between the two discharge electrodes. At the focal position of the pulsed laser, the compressed air contained in the air jet contacts the pulsed laser and undergoes optical breakdown and ionization to generate plasma. When the discharge electrode is connected to a power source, the plasma induces arc plasma between the two discharge electrodes. The arc plasma is directionally twisted toward a workpiece to be processed under the impact of the air jet, and the power density of the arc plasma is greater than the ablation threshold of the workpiece material to be processed.

2. The laser directional induced arc discharge milling system according to claim 1, characterized in that: The optical axis of the focused pulsed laser, the central axis of the air jet, and the central axis of the gap between the two discharge electrodes coincide with each other; Preferably, the two discharge electrodes are arranged in mirror symmetry, and the optical axis of the pulsed laser, the central axis of the air jet, and the symmetry axes of the two discharge electrodes coincide with each other.

3. The laser directional induced arc discharge milling system according to claim 1 or 2, characterized in that: The air jet module comprises an air compressor and a nozzle, wherein the air compressor is in communication with the nozzle; The laser module comprises a laser, other optical path components and a focusing lens, wherein the other optical path components are used to guide the pulse laser emitted by the laser to the focusing lens, and the focusing lens is used to focus the pulse laser on the gap between the two discharge electrodes; Wherein, the nozzle is located between the focusing lens and the electrode pair, and the outlet of the nozzle faces the gap between the electrode pair; Preferably, the arc generating module further comprises a power supply, and the power supply is electrically connected to the electrode pair; Preferably, the power supply comprises a DC power supply; Preferably, the laser is a high-power millisecond laser; Preferably, the laser module further comprises a positioning detection mechanism, and the positioning detection mechanism is used to locate the trajectory of the pulsed laser; Preferably, the positioning detection mechanism comprises a CCD camera, and the CCD camera emits a visible light beam, and the visible light beam passes through other optical path components and a focusing lens to form a positioning light beam with the same optical axis as the pulse laser.

4. The laser directional induced arc discharge milling system according to claim 3, characterized in that: The discharge electrodes are arranged obliquely, and the distance between the two discharge electrodes gradually decreases along the flow direction of the air jet; Preferably, the narrowest distance between the two discharge electrodes is 1 mm to 3 mm.

5. The laser directional induced arc discharge milling system according to claim 3, characterized in that: Also includes: An electrode compensation module, the electrode compensation module is used to fix the electrode pair; Preferably, the electrode compensation module comprises two sets of electrode assembly racks, and each of the discharge electrodes is assembled on one of the electrode assembly racks; Preferably, the electrode assembly frame comprises a brush holder, an electrode track, a support seat, and a stopper, wherein the electrode track is fixedly arranged on the support seat, the discharge electrode is arranged in the electrode track and movably cooperates with the electrode track, the brush holder is fixedly arranged at the end of the electrode track and electrically connected to the discharge electrode, the stopper is fixedly arranged at the front end of the electrode track, an opening is arranged on the stopper, the end surface of the discharge electrode is exposed from the opening, and the two ends of the discharge electrodes close to the stopper have the narrowest distance between them; Preferably, the brush holder further comprises an elastic member, and the elastic member is elastically matched with the discharge electrode.

6. The laser directional induced arc discharge milling system according to claim 3, characterized in that: Also includes: A motion unit, the motion unit is in transmission cooperation with the milling unit and the workpiece to be processed, and is used to drive the milling unit and the workpiece to be processed to generate relative motion, so as to form a specific processing shape on the workpiece to be processed, wherein the relative motion includes relative linear motion along at least one of the x-axis, y-axis, and z-axis of a three-dimensional coordinate system and / or relative rotational motion around at least one of the x-axis, y-axis, and z-axis of a three-dimensional coordinate system; Preferably, the motion unit comprises a five-axis motion platform; Preferably, the electrode pair of the arc generating module, the nozzle of the air jet module, other optical path components and the lens of the laser module are installed on the z-axis slide of the five-axis motion platform, the linear module of the z-axis slide is installed on the x-axis slide, and the workpiece to be processed is set on the cradle turntable of the five-axis motion platform.

7. The laser directional induced arc discharge milling system according to claim 1, characterized in that: Also includes: a current detection unit, the current detection unit being electrically connected to the arc generating module and being used at least to monitor the machining current; Preferably, the current detection unit comprises an oscilloscope and a current probe, the oscilloscope is electrically connected to the current probe, and the current probe is electrically connected to a wire connecting a power source and the electrode pair.

8. A laser directional induced arc discharge milling method, characterized in that: include: Power is supplied to two discharge electrodes of the electrode pair by a power source, the two discharge electrodes are arranged at an interval, and the narrowest width of the gap between the two discharge electrodes is larger than the air discharge gap distance, and air jet and pulse laser are provided, and the air jet flows through the gap between the two discharge electrodes, the pulse laser is converged in the gap between the two discharge electrodes, and the pulse laser is focused between the two discharge electrodes; At the focal position of the pulse laser, the compressed air contained in the air jet contacts the pulse laser and undergoes optical breakdown and ionization to generate plasma, and the plasma induces arc plasma between the two discharge electrodes. The arc plasma is directionally twisted toward a workpiece to be processed under the impact of the air jet and contacts the workpiece to be processed. The power density of the arc plasma is greater than the ablation threshold of the material of the workpiece to be processed, and a part of the workpiece to be processed is ablated and removed, thereby achieving processing of the workpiece to be processed.

9. The laser directional induced arc discharge milling method according to claim 8, characterized in that: Also includes: The arc plasma and the workpiece to be processed are caused to move relative to each other, and the movement trajectory of the arc plasma is copied on the workpiece to be processed to form a specific shape.

10. The laser directional induced arc discharge milling method according to claim 8 or 9, characterized in that: The laser directional induced arc discharge milling processing method is implemented based on the laser directional induced arc discharge milling processing system according to any one of claims 1 to 7; Preferably, the workpiece to be processed is made of a hard and brittle material.

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