Laser direct induction arc discharge milling system and method

Abstract

The application discloses a laser directional induction electric arc discharge milling machining system and a machining method. The application utilizes laser to break air to directionally trigger electric arc combustion to efficiently remove materials, simultaneously, with the help of air jet under a large discharge gap, the electric arc is effectively broken, continuous electric arc burn of a workpiece is avoided, and the workpiece conductivity is not needed to be considered, through cooperation with a multi-axis motion platform, an electric arc plasma motion track is copied on the workpiece to form a specific complex profile, so that a high-performance material complex part feature high-efficiency and high-precision machining method is realized.

Description

Technical Field

[0001] This invention relates to a laser-guided arc discharge milling system and method, belonging to the field of special machining technology. Background Technology

[0002] The aerospace manufacturing process utilizes a large number of high-performance materials, such as nickel-based alloys, titanium alloys, metal matrix composites, and ceramic matrix composites. These materials typically possess comprehensive properties including high hardness, high strength, high temperature resistance, and corrosion resistance, and their properties are continuously enhanced as aircraft performance improves. For some large structural components or pressure vessels, such as connecting frames and casings, the material removal rate is very high, posing a significant challenge to traditional machining industries.

[0003] Traditional machining methods, when dealing with these high-performance materials, suffer from severe tool wear due to their strong cutting forces. For hard and brittle materials, the machining process can also lead to internal defects. Specialized machining methods such as laser processing, electrical discharge machining (EDM), arc machining, and electrochemical machining, which involve no significant contact stress and rely on thermal or electrochemical energy to remove material, each have their specific advantages and applications. Macroscopic laser processing uses a high-energy-density laser beam to irradiate the material surface, causing the material to ablate, melt, and evaporate. It has high processing efficiency, but the heat-affected zone is large, and the energy gradually attenuates when penetrating thick workpieces, resulting in uneven processing depth. EDM offers high precision, capable of completely replicating complex electrode shapes or motion trajectories onto the workpiece to form specific contours, and the heat-affected zone is controllable. However, its processing efficiency is relatively low, and electrode wear occurs. Arc machining, as a derivative of EDM, significantly improves the efficiency of electrical discharge machining, but requires strict control of the arc switching time; otherwise, continuous arc burning of the workpiece can easily occur, producing a significant recast layer and heat-affected zone. Electrolytic machining produces no significant thermal stress, resulting in high-quality machined surfaces. However, it requires strict control of the flow field and maintaining a constant dielectric conductivity; otherwise, uneven dissolution can compromise machining accuracy. Furthermore, electrical discharge machining, arc machining, and electrolytic machining all require conductive materials. For non-conductive or weakly conductive materials, such as ceramic matrix composites, machining is highly limited. Summary of the Invention

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

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0006] A first aspect of the present invention provides a laser-directed induced arc discharge milling system, comprising a milling unit, the milling unit including:

[0007] An arc generating module, the arc generating module including an electrode pair, the electrode pair including two spaced-apart discharge electrodes, the narrowest width of the gap between the two discharge electrodes being greater than the air discharge gap distance;

[0008] An air jet module, the air jet module being used at least to provide an air jet that flows through the gap between the two discharge electrodes;

[0009] A laser module is provided to provide a pulsed laser and focus the pulsed laser into the gap between two discharge electrodes. The pulsed laser is focused between the two discharge electrodes. At the focal point of the pulsed laser, the compressed air contained in the air jet comes into contact with the pulsed laser and undergoes optical breakdown and ionization to generate plasma. When the discharge electrodes are connected to a power source, the plasma induces the generation of an arc plasma between the two discharge electrodes. The arc plasma undergoes directional distortion toward the workpiece under the impact of the air jet. The power density of the arc plasma is greater than the ablation threshold of the workpiece material.

[0010] A second aspect of the present invention provides a laser-guided induced arc discharge milling method, comprising:

[0011] Power is supplied to the two discharge electrodes of the electrode pair, the two discharge electrodes are spaced apart, and the narrowest width of the gap between the two discharge electrodes is greater than the air discharge gap distance; an air jet and a pulsed laser are provided, and the air jet flows through the gap between the two discharge electrodes, the pulsed laser is focused into the gap between the two discharge electrodes, and the pulsed laser is focused between the two discharge electrodes.

[0012] At the focal point of the pulsed laser, the compressed air contained in the air jet comes into contact with the pulsed laser and undergoes optical breakdown and ionization to generate plasma. The plasma induces the generation of arc plasma between the two discharge electrodes. Under the impact of the air jet, the arc plasma undergoes directional distortion toward the workpiece to be processed and comes into contact with the workpiece. The power density of the arc plasma is greater than the ablation threshold of the workpiece material, and a portion of the workpiece is ablated and removed, thereby achieving the processing of the workpiece.

[0013] Compared with the prior art, the advantages of the present invention include:

[0014] The present invention provides a laser-guided arc discharge milling system and method that utilizes a high-power pulsed laser focus in conjunction with compressed air to generate arc plasma in a timed and directional manner within the discharge electrode gap exceeding the discharge distance, thereby improving the control accuracy of the DC arc plasma.

[0015] The present invention provides a laser-directed induced arc discharge milling system and method, which utilizes the plasma generated by air breakdown to absorb laser energy and induce arc plasma. The arc plasma absorbs the laser energy before the remaining pulse is turned off, and the adaptive shielding is high, which can reduce laser damage to the processed surface.

[0016] The present invention provides a laser-guided arc discharge milling system and method, in which a compressed air jet impacts and twists the arc column under a wide discharge gap, resulting in higher arc breaking efficiency, preventing the generation of continuous arcs, reducing thermal damage to the workpiece, and combining with a CNC system for layer-by-layer milling, achieving higher machining accuracy.

[0017] The present invention provides a laser-guided arc discharge milling system and method, wherein the center temperature of the arc column region can reach tens of thousands of degrees Celsius, which can rapidly melt and vaporize the workpiece material and achieve a high material removal rate.

[0018] The present invention provides a laser-guided arc discharge milling system and method. Since the workpiece is not a current loop, there is no need to consider the conductivity of the workpiece material. Only the heat transfer performance of the workpiece needs to be considered. This means that the technology can achieve efficient processing of non-conductive materials.

[0019] The present invention provides a laser-guided arc discharge milling system and method. This processing technology, combined with multi-axis linkage and CAM software, replicates the arc plasma motion trajectory on the workpiece to form a specific contour, thereby realizing the processing of complex curved surfaces or contours. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a laser-directed induced arc discharge milling system provided in a typical embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of a laser-directed induced arc discharge milling method provided in a typical embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of a single arc triggering, combustion, and shutdown process in a laser-guided arc discharge milling process, provided in a typical embodiment of the present invention.

[0023] Figure 4This is a real-time matching diagram of laser power and arc discharge waveform. Detailed Implementation

[0024] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate the technical solution, its implementation process, and its principles.

[0025] This invention utilizes laser-induced air-directed arc combustion to efficiently remove materials. Simultaneously, it leverages a large discharge gap and air jet to effectively interrupt the arc, preventing continuous arc burns to the workpiece. Furthermore, it eliminates the need to consider the workpiece's conductivity. By cooperating with a multi-axis motion platform, the arc plasma trajectory is replicated onto the workpiece to form a specific complex contour. This invention is applicable to efficient and high-precision machining methods for complex parts made of high-performance materials.

[0026] This invention utilizes a high-power laser focus to break down compressed air between discharge electrodes that exceed the discharge gap, forming plasma. The plasma has a high electron density, reducing the air breakdown threshold between the electrodes and causing an electric arc to be generated and burned near the focus between the discharge electrodes. Subsequently, the laser is in a pulse interval and can no longer generate plasma. The nozzle coaxial with the laser ejects compressed air to continuously scour the arc plasma, causing it to twist to the workpiece surface, thus achieving efficient material removal. Due to the wide gap between the discharge electrodes, the arc column is broken by the air jet before the next laser-induced plasma occurs, completing one arc extinguishing.

[0027] This invention uses a high-power laser to trigger an electric arc discharge and uses an air jet to direct the arc combustion. Because 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 electric arc, and there is no need to consider the conductivity of the workpiece. With the electrode compensation device in the machining system, long-term continuous machining can be achieved. Combined with five-axis linkage, it can achieve efficient machining of complex curved surfaces and cavities.

[0028] A first aspect of the present invention provides a laser-directed induced arc discharge milling system, comprising a milling unit, the milling unit including:

[0029] An arc generating module, the arc generating module including an electrode pair, the electrode pair including two spaced-apart discharge electrodes, the narrowest width of the gap between the two discharge electrodes being greater than the air discharge gap distance;

[0030] An air jet module, the air jet module being used at least to provide an air jet that flows through the gap between the two discharge electrodes;

[0031] A laser module is provided to provide a pulsed laser and focus the pulsed laser into the gap between two discharge electrodes. The pulsed laser is focused between the two discharge electrodes. At the focal point of the pulsed laser, the compressed air contained in the air jet comes into contact with the pulsed laser and undergoes optical breakdown and ionization to generate plasma. When the discharge electrodes are connected to a power source, the plasma induces the generation of an arc plasma between the two discharge electrodes. The arc plasma undergoes directional distortion toward the workpiece under the impact of the air jet. The power density of the arc plasma is greater than the ablation threshold of the workpiece material.

[0032] Furthermore, 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.

[0033] Furthermore, the two discharge electrodes are arranged in a mirror-symmetric manner, and the optical axis of the pulsed laser, the central axis of the air jet, and the axis of symmetry of the two discharge electrodes coincide.

[0034] In a more specific implementation, the air jet module includes an air compressor and a nozzle, the air compressor being connected to the nozzle;

[0035] The laser module includes a laser, other optical path components, and a focusing lens. The other optical path components are used to guide the pulsed laser emitted by the laser to the focusing lens, and the focusing lens is used to focus the pulsed laser into the gap between the two discharge electrodes.

[0036] The nozzle is located between the focusing lens and the electrode pair, and the nozzle outlet faces the gap between the electrode pairs.

[0037] Furthermore, the arc generating module also includes a power supply, which is electrically connected to the electrode pair.

[0038] Furthermore, the power source includes a DC power source.

[0039] Furthermore, the laser is a high-power millisecond laser.

[0040] Furthermore, the other optical path components include optical elements such as dichroic mirrors.

[0041] In a more specific implementation, the laser module further includes a positioning detection mechanism for locating the trajectory of the pulsed laser.

[0042] Furthermore, the positioning detection mechanism includes a CCD camera that emits a visible light beam, which passes through other optical path components and a focusing lens to form a positioning beam coaxial with the pulsed laser.

[0043] In a more specific embodiment, the discharge electrodes are inclined, and the distance between the two discharge electrodes gradually decreases along the flow direction of the air jet.

[0044] Furthermore, the narrowest distance between the two discharge electrodes is 1mm to 3mm.

[0045] In a more specific implementation, the laser-guided arc discharge milling system further includes an electrode compensation module, which is used to fix the electrode pair.

[0046] Furthermore, the electrode compensation module includes two sets of electrode mounting frames, with each discharge electrode mounted on one of the electrode mounting frames.

[0047] Furthermore, the electrode assembly frame includes a brush holder, an electrode track, a support base, and a stop block. The electrode track is fixedly mounted on the support base, and the discharge electrode is mounted inside the electrode track and movably engages with it. The brush holder is fixedly mounted at the end of the electrode track and electrically connected to the discharge electrode. The stop block is fixedly mounted at the front end of the electrode track, and an opening is provided on the stop block. The end face of the discharge electrode protrudes from the opening, and the two discharge electrodes have a narrowest distance between their ends closest to the stop block.

[0048] Furthermore, the brush holder also has an elastic element that elastically engages with the discharge electrode.

[0049] In a more specific implementation, the laser-guided arc discharge milling system further 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 generate relative motion, so as to form a specific processing shape on the workpiece to be processed. 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 about at least one of the x-axis, y-axis, and z-axis of a three-dimensional coordinate system.

[0050] Furthermore, the motion unit includes a five-axis motion platform.

[0051] 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 mounted on the z-axis slide of the five-axis motion platform, the linear module of the z-axis slide is mounted on the x-axis slide, and the workpiece to be processed is placed on the cradle turntable of the five-axis motion platform.

[0052] In a more specific implementation, the laser-guided arc discharge milling system further includes: a current detection unit, which is electrically connected to the arc generating module and is used at least to monitor the machining current;

[0053] Furthermore, the current detection unit includes an oscilloscope and a current probe, the oscilloscope being electrically connected to the current probe, and the current probe being electrically connected to a wire connecting a power supply and the electrode pair.

[0054] A second aspect of the present invention provides a laser-guided induced arc discharge milling method, comprising:

[0055] Power is supplied to the two discharge electrodes of the electrode pair, the two discharge electrodes are spaced apart, and the narrowest width of the gap between the two discharge electrodes is greater than the air discharge gap distance; an air jet and a pulsed laser are provided, and the air jet flows through the gap between the two discharge electrodes, the pulsed laser is focused into the gap between the two discharge electrodes, and the pulsed laser is focused between the two discharge electrodes.

[0056] At the focal point of the pulsed laser, the compressed air contained in the air jet comes into contact with the pulsed laser and undergoes optical breakdown and ionization to generate plasma. The plasma induces the generation of arc plasma between the two discharge electrodes. Under the impact of the air jet, the arc plasma undergoes directional distortion toward the workpiece to be processed and comes into contact with the workpiece. The power density of the arc plasma is greater than the ablation threshold of the workpiece material, and a portion of the workpiece is ablated and removed, thereby achieving the processing of the workpiece.

[0057] In a more specific implementation, the laser-guided arc discharge milling method further includes: causing the arc plasma to move relative to the workpiece to be processed, and copying the motion trajectory of the arc plasma onto the workpiece to form a specific shape.

[0058] Furthermore, the laser-guided arc discharge milling method is implemented based on the laser-guided arc discharge milling system.

[0059] Furthermore, the material of the workpiece to be processed is a hard and brittle material.

[0060] The following will further explain the technical solution, its implementation process and principle in conjunction with the accompanying drawings and specific implementation examples. Unless otherwise specified, the laser, discharge electrode, focusing lens and other optical components, power supply, computer, water chiller, CCD camera, air compressor, nozzle, oscilloscope, control cabinet and five-axis motion platform used in the embodiments of the present invention are all known in the art and can be obtained commercially. The specific equipment structure and model are not limited here.

[0061] In a typical implementation case, please refer to Figure 1 A laser-guided 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.

[0062] Two discharge electrodes 4 are electrically connected to a power supply 8, and are spaced apart. The narrowest width of the gap between the two discharge electrodes 4 is greater than the air discharge gap distance. A nozzle 21 is connected to an air compressor and is positioned above the gap between the two discharge electrodes 4. Compressed air supplied by the air compressor enters the nozzle 21 and is accelerated to form an air jet 3. A laser 11 provides a high-power pulsed laser beam 2. A dichroic mirror 14 and a focusing lens 1 are sequentially arranged in the optical path of the pulsed laser beam 2. The focusing lens 1 is positioned directly above the nozzle 21. The dichroic mirror 14 reflects the pulsed laser beam 2 to the focusing lens 1, which focuses the pulsed laser beam 2 to form a focused beam. The focused beam passes through the gap between the two discharge electrodes 4, and the focal point of the pulsed laser beam 2 is located within the gap between the two discharge electrodes 4. Specifically, the gap between the ends of the two discharge electrodes 4 furthest from the nozzle 21 has the narrowest width, and the focal point of the pulsed laser beam 2 is preferably located near the ends of the two discharge electrodes 4 furthest from the nozzle 21.

[0063] More specifically, the two discharge electrodes 4 are inclined, specifically inclined from the end near the nozzle 21 toward each other, that is, the distance 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 mirror-symmetrically arranged, and the axis of symmetry 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.

[0064] Specifically, the power supply 8 can be a DC power supply, and it is electrically connected to the two discharge electrodes 4 via wires. For example, the narrowest distance between the two discharge electrodes 4 can be 1mm to 3mm, and the material of the discharge electrodes 4 is high-melting-point graphite. Specifically, the air compressor is connected to the nozzle 21 via an air supply line. More specifically, the nozzle 21 and the air supply line are connected via a quick-connect connector 20. Compressed air enters the nozzle 21 through the quick-connect connector 20, is accelerated, and forms an air jet 3 coaxial with the pulsed laser beam 2.

[0065] For details, please refer to Figure 2 The power supply 8 continuously supplies electrical energy to the discharge electrode 4. Since the narrowest distance between the two discharge electrodes 4 is greater than the air discharge gap distance, the two discharge electrodes 4 will not spontaneously generate discharge. The pulsed laser beam 2 focuses the focal point near the gap between the two discharge electrodes 4 through the focusing lens 1. The air jet 3, which is coaxial with the pulsed laser beam 2, flows through the gap between the two discharge electrodes 4. At the focal point, the pulsed laser beam 2 causes the compressed air in the air jet 3 to undergo optical breakdown and ionization to generate plasma. The plasma induces the two discharge electrodes 4 to generate arc plasma 5. Under the action of the air jet 3, the arc plasma 5 is twisted toward the workpiece 6 and comes into contact with the workpiece 6. The power density of the arc plasma 5 is greater than the ablation threshold of the workpiece 6 material. The workpiece 6 is partially ablated and removed, realizing the directional and efficient removal of the workpiece material. The molten material forms the processing product 7.

[0066] For details, please refer to Figure 3 , Figure 3 This diagram illustrates the single-stage arc triggering, combustion, and shutdown process in laser-guided arc discharge milling. The narrowest distance between the discharge electrodes 4 is slightly larger than the air discharge gap, preventing air breakdown. The pulsed laser beam 2 is focused into 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 high energy density of the pulsed laser beam 2 causes optical breakdown and ionization of the air at the focal point, generating plasma 26. The electron density inside plasma 26 is very high. As plasma 26 diffuses, the air breakdown threshold in the gap between the discharge electrodes 4 decreases, and air breakdown occurs at a distance greater than the discharge gap, generating arc plasma 5. Subsequently, the laser is in a pulse interval, while the air jet 3 continuously acts on the arc plasma 5, causing the arc column to twist and rush towards the workpiece 6. The workpiece material is melted by thermal energy, creating a pit 27. The distance between the pit 27 and the arc plasma 5 increases. Combined with the continuous scouring effect of the air jet 3, the arc column is easily extinguished, completing the arc breakup. In addition, the air jet 3 also causes the processed product 7 to be discharged from the processing area, keeping the processed surface clean.

[0067] Specifically, the laser 11 is preferably a high-power millisecond laser, so the duration and off-time of a single pulse are on the order of milliseconds. When the pulsed laser beam 2 just acts on the air jet 3 in the gap of the discharge electrode 4, it excites and generates plasma 26, which gradually expands as the peak power of the laser increases. When the expansion is maintained at the peak power, an arc is instantly generated to produce arc plasma 5. Subsequently, the laser power decreases. During this process, the air jet 3 continues to act on the arc plasma 5 to make it lengthen and twist, resulting in an increase in the internal resistance of the arc. The current gradually decreases and shows a small range of fluctuations. When the laser power is 0, the arc is still ablating the workpiece material. After the discharge pit 27 is generated, the gap increases and the internal resistance of the arc further increases. Combined with the scouring effect of the air jet 3, the arc is extinguished and the current is 0. The time from the generation to the extinguishing of the arc is also on the order of milliseconds. Therefore, the arc can be adjusted by timing the laser pulse and the air jet.

[0068] For details, please refer to the following document again. Figure 1 To assemble the discharge electrodes, the laser-guided arc discharge milling system also includes an electrode compensation module. This module is used to fix an electrode pair consisting of two discharge electrodes. The module includes two sets of electrode mounting frames, with each discharge electrode mounted on one frame. More specifically, the electrode mounting frame includes a brush holder 22, an electrode track 25, a support base 23, and a stop 24. The discharge electrode 4 is positioned within the electrode track 25 and movably engages with it. The electrode track 25 is fixedly mounted on the support base 23 and supported and fixed by it. The brush holder 22 is fixedly positioned at the end (tail) of the electrode track 25 and electrically connected to the discharge electrode 4. The stop 24 is fixedly positioned at the front end of the electrode track 25. The stop 24 has an opening slightly smaller than the diameter of the discharge electrode, through which the end face of the discharge electrode 4 protrudes. The two discharge electrodes 4 have a narrowest distance between their ends closest to the stop 24. More specifically, the brush holder 22 has an elastic element inside, which continuously pushes the discharge electrode 4, and cooperates with the front stop 24 to achieve electrode compensation. The power supply 8 is electrically connected to the brush holder 22 and provides power to the discharge electrode 4 through the brush holder 22.

[0069] For details, please refer to the following document again. Figure 1 To monitor the machining current of the discharge electrodes, the laser-guided arc discharge milling system also includes a current detection unit. This unit is electrically connected to the discharge electrodes 4 and is 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, and the current probe and 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 terminals of the power supply 8 to monitor the machining current. More specifically, the oscilloscope 15 is also connected to a second computer 16, and the machining current obtained by the oscilloscope 15 is displayed on the screen of the computer 16, reflecting the machining status in real time.

[0070] For details, please refer to the following document again. Figure 1 To calibrate the machining position, the laser-guided arc discharge milling system also includes a positioning and detection mechanism, which is used to locate the trajectory of the pulsed laser beam. Specifically, the positioning and detection mechanism includes a CCD camera 12, a lens 13, a dichroic mirror 14, and a focusing lens 1, all arranged coaxially. The pulsed laser beam 2 emitted by the laser 11 is reflected by the dichroic mirror 14 and enters the focusing lens 1 to form a focused beam, which is then incident on the gap of the discharge electrode 4. The CCD camera 12 emits a visible beam, which passes sequentially through the lens 13, the dichroic mirror 14, and the focusing lens 1 to form a positioning beam. The positioning beam is coaxial with the pulsed laser beam to calibrate the machining position.

[0071] For details, please refer to the following document again. Figure 1 The laser-guided arc discharge milling system also includes a first computer 9 and a water chiller 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 switch it on and off. The water chiller 10 works with the laser 11 and is used to regulate the temperature of the laser 11 so that the laser 11 can maintain stable operation. It should be noted that the first computer 9 and the water chiller 10 are known in the art. The CNC system / software contained in the first computer 9 can also be obtained commercially. No specific limitation is made here. Of course, the water chiller 10 can also be replaced with other temperature control devices.

[0072] For details, please refer to the following document again. Figure 1In order to better achieve the desired shape structure in the workpiece, the laser-directed induced arc discharge milling system also includes a motion processing platform (i.e., the aforementioned motion processing unit). The motion processing platform is used to generate relative motion between the arc plasma 5 and the workpiece 6. 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 achieve 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, nozzle 21, and focusing lens 1 are all mounted on the Z-axis slide 19, so that the laser beam 2, discharge electrode 4, and air jet 3 maintain synchronous movement. The Z-axis slide is mounted on the X-axis slide, and the workpiece 6 is fixed on the cradle turntable 18. The cradle turntable 18 is mounted on the Y-axis slide, and 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, Y-axis slide, and Z-axis slide, as well as the cradle platform 18, are all connected to and controlled by the control cabinet 17. The control cabinet 17 is also connected to the second computer 16, which inputs commands 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 the five-axis linkage of 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 to control the platform movement through code.

[0073] It should be noted that the five-axis motion platform also includes other structures capable of five-axis motion besides the X-axis slide, Y-axis slide, Z-axis slide and cradle turntable 18. These are all known in the art, and their specific structural composition and the configuration relationship between the components are not limited here. The control cabinet 17 and the control system used by the second computer are also known in the art, and are not specifically limited here.

[0074] Furthermore, the electrode pairs of the arc generating module, the nozzle of the air jet module, other optical path components of the laser module, and the lens are mounted on the z-axis slide of the five-axis motion platform, the linear module of the z-axis slide is mounted on the x-axis slide, and the workpiece to be processed is placed on the cradle turntable of the five-axis motion platform.

[0075] In a typical implementation case, the following was adopted: Figure 1 A method for milling using a laser-guided arc discharge milling system, as shown, may include the following steps:

[0076] (1) The power supply provides excitation energy to the discharge electrodes. The discharge electrodes are arranged symmetrically, and their narrowest distance slightly exceeds the distance of the discharge gap to prevent continuous arcing from burning the workpiece in the narrow gap and reduce the arc breaking pressure.

[0077] (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 point of the high-power laser beam is the highest, which produces optical breakdown and electron avalanche, forming local plasma.

[0078] (3) The high electron density of the plasma reduces the air breakdown threshold between the discharge electrodes, and the conditions for arc ignition are met outside the discharge gap, thus exciting the arc plasma.

[0079] (4) After the laser energy is absorbed by the plasma, it is in the pulse off period, but the electric arc continues to burn. The coaxial air jet rushes towards the electric arc plasma and twists it downward. At this time, it is brought close to the workpiece and melts the material with the help of thermal energy. As the material is eroded, the gap between the workpiece and the plasma increases. The coaxial air jet breaks the electric arc plasma and ends the discharge.

[0080] (5) The laser acts as a trigger switch for the electric arc, causing the electric arc to be generated and shut off intermittently, and the material removal process is repeated. The control system controls the linkage of X, Y, Z, A, and C, so that the movement trajectory of the electric arc is copied onto the workpiece to form a specific shape.

[0081] The present invention provides a laser-guided arc discharge milling system and method that utilizes a high-power pulsed laser focus in conjunction with compressed air to generate arc plasma in a timed and directional manner within the discharge electrode gap exceeding the discharge distance, thereby improving the control accuracy of the DC arc plasma.

[0082] The present invention provides a laser-directed induced arc discharge milling system and method, which utilizes the plasma generated by air breakdown to absorb laser energy and induce arc plasma. The arc plasma absorbs the laser energy before the remaining pulse is turned off, and the adaptive shielding is high, which can reduce laser damage to the processed surface.

[0083] The present invention provides a laser-guided arc discharge milling system and method, in which a compressed air jet impacts and twists the arc column under a wide discharge gap, resulting in higher arc breaking efficiency, preventing the generation of continuous arcs, reducing thermal damage to the workpiece, and combining with a CNC system for layer-by-layer milling, achieving higher machining accuracy.

[0084] The present invention provides a laser-guided arc discharge milling system and method, wherein the center temperature of the arc column region can reach tens of thousands of degrees Celsius, which can rapidly melt and vaporize the workpiece material and achieve a high material removal rate.

[0085] The present invention provides a laser-guided arc discharge milling system and method. Since the workpiece is not a current loop, there is no need to consider the conductivity of the workpiece material. Only the heat transfer performance of the workpiece needs to be considered. This means that the technology can achieve efficient processing of non-conductive materials.

[0086] The present invention provides a laser-guided arc discharge milling system and method. This processing technology, combined with multi-axis linkage and CAM software, replicates the arc plasma motion trajectory on the workpiece to form a specific contour, thereby realizing the processing of complex curved surfaces or contours.

[0087] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A laser-guided arc discharge milling system, characterized in that, The milling unit includes: An arc generating module, the arc generating module including an electrode pair, the electrode pair including two spaced-apart discharge electrodes, 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 being used at least to provide an air jet that flows through the gap between the two discharge electrodes; A laser module is provided to provide a pulsed laser and focus the pulsed laser into the gap between two discharge electrodes. At the focal point of the pulsed laser, compressed air contained in the air jet comes into contact with the pulsed laser and undergoes optical breakdown and ionization to generate plasma. When the discharge electrodes are connected to a power source, the plasma induces the generation of an arc plasma between the two discharge electrodes. Under the impact of the air jet, the arc plasma undergoes directional distortion toward the workpiece to be processed. The power density of the arc plasma is greater than the ablation threshold of the workpiece material.

2. The laser-guided 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.

3. The laser-guided arc discharge milling system according to claim 2, characterized in that: The two discharge electrodes are arranged in a mirror-symmetric configuration, and the optical axis of the pulsed laser, the central axis of the air jet, and the axis of symmetry of the two discharge electrodes coincide.

4. The laser-guided induced arc discharge milling system according to claim 1, 2, or 3, characterized in that: The air jet module includes an air compressor and a nozzle, and the air compressor is connected to the nozzle; The laser module includes a laser, other optical path components, and a focusing lens. The other optical path components are used to guide the pulsed laser emitted by the laser to the focusing lens, and the focusing lens is used to focus the pulsed laser on the gap between the two discharge electrodes. The nozzle is located between the focusing lens and the electrode pair, and the nozzle outlet faces the gap between the electrode pairs.

5. The laser-guided arc discharge milling system according to claim 4, characterized in that: The arc generating module also includes a power supply, which is electrically connected to the electrode pair.

6. The laser-guided induced arc discharge milling system according to claim 5, characterized in that: The power source includes a DC power source.

7. The laser-guided induced arc discharge milling system according to claim 4, characterized in that: The laser is a high-power millisecond laser.

8. The laser-guided induced arc discharge milling system according to claim 4, characterized in that: The laser module also includes a positioning and detection mechanism, which is used to locate the trajectory of the pulsed laser.

9. The laser-guided induced arc discharge milling system according to claim 8, characterized in that: The positioning detection mechanism includes a CCD camera that emits a visible light beam. The visible light beam passes through other optical path components and a focusing lens to form a positioning beam that is coaxial with the pulsed laser.

10. The laser-guided induced arc discharge milling system according to claim 4, characterized in that: The discharge electrodes are inclined, and the distance between the two discharge electrodes gradually decreases along the flow direction of the air jet.

11. The laser-guided induced arc discharge milling system according to claim 10, characterized in that: The narrowest distance between the two discharge electrodes is 1 mm to 3 mm.

12. The laser-guided arc discharge milling system according to claim 4, characterized in that, Also includes: An electrode compensation module is used to fix the electrode pair.

13. The laser-guided arc discharge milling system according to claim 12, characterized in that: The electrode compensation module includes two sets of electrode mounting frames, with each discharge electrode mounted on one of the electrode mounting frames.

14. The laser-guided arc discharge milling system according to claim 13, characterized in that: The electrode assembly frame includes a brush holder, an electrode track, a support base, and a stop block. The electrode track is fixedly mounted on the support base. The discharge electrode is mounted inside the electrode track and movably engages with it. The brush holder is fixedly mounted at the end of the electrode track and electrically connected to the discharge electrode. The stop block is fixedly mounted at the front end of the electrode track. The stop block has an opening through which the end face of the discharge electrode protrudes. The two discharge electrodes have a narrowest distance between their ends closest to the stop block.

15. The laser-guided induced arc discharge milling system according to claim 14, characterized in that: The brush holder also has an elastic element that elastically engages with the discharge electrode.

16. The laser-guided induced arc discharge milling system according to claim 4, characterized in that, 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 generate relative motion, so as to form a specific processing shape on the workpiece to be processed. 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 about at least one of the x-axis, y-axis and z-axis of a three-dimensional coordinate system.

17. The laser-guided arc discharge milling system according to claim 16, characterized in that: The motion unit includes a five-axis motion platform.

18. The laser-guided induced arc discharge milling system according to claim 17, characterized in that: The electrode pairs of the arc generating module, the nozzle of the air jet module, other optical path components of the laser module, and the lens are mounted on the z-axis slide of the five-axis motion platform. The linear module of the z-axis slide is mounted on the x-axis slide, and the workpiece to be processed is placed on the cradle turntable of the five-axis motion platform.

19. The laser-guided induced arc discharge milling system according to claim 1, characterized in that, Also includes: A current detection unit is electrically connected to the arc generating module and is used at least to monitor the processing current.

20. The laser-guided arc discharge milling system according to claim 19, characterized in that: 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 that connects the power supply and the electrode pair.

21. A laser-guided arc discharge milling method, characterized in that, The laser-guided arc discharge milling method is implemented based on the laser-guided arc discharge milling system according to any one of claims 1-20, and the laser-guided arc discharge milling method includes: Power is supplied to the two discharge electrodes of the electrode pair, the two discharge electrodes are spaced apart, and the narrowest width of the gap between the two discharge electrodes is greater than the air discharge gap distance; an air jet and a pulsed laser are provided, and the air jet flows through the gap between the two discharge electrodes, the pulsed laser is focused into the gap between the two discharge electrodes, and the pulsed laser is focused between the two discharge electrodes. At the focal point of the pulsed laser, the compressed air contained in the air jet comes into contact with the pulsed laser and undergoes optical breakdown and ionization to generate plasma. The plasma induces the generation of arc plasma between the two discharge electrodes. Under the impact of the air jet, the arc plasma undergoes directional distortion toward the workpiece to be processed and comes into contact with the workpiece. The power density of the arc plasma is greater than the ablation threshold of the workpiece material, and a portion of the workpiece is ablated and removed, thereby achieving the processing of the workpiece.

22. The laser-guided induced arc discharge milling method according to claim 21, characterized in that, Also includes: The electric arc plasma is made to move relative to the workpiece to be processed, and the motion trajectory of the electric arc plasma is copied onto the workpiece to form a specific shape.

23. The laser-guided induced arc discharge milling method according to claim 21 or 22, characterized in that: The workpiece to be processed is made of a hard and brittle material.

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