Electrochemical discharge-laser-dynamic wet etching processing system, method and application

Abstract

The invention discloses an electrochemical discharge-laser-dynamic wet etching processing system and method and application, and belongs to the field of non-traditional processing. The electrochemical discharge-laser-dynamic wet etching combined machining system comprises an electrochemical discharge machining module, a laser processing module and a dynamic wet etching module, wherein the electrochemical discharge machining module is used for performing electrochemical discharge machining on a first area of a workpiece; the laser processing module is used for carrying out laser ablation processing on a second area of the workpiece, and the first area is distributed around the second area; and the jet flow module is used for conducting jet flow washing on the machining area of the workpiece, and the machining area comprises a second area and a first area. According to the method, the advantage of high precision of electrochemical discharge machining is combined, the machining efficiency is improved through laser machining, the oxide layer generated in the machining process of the workpiece material is selectively etched through the dynamic chemical solution, the solution state is updated in time, and therefore the machining scheme with high efficiency, high precision and high surface quality is formed.

Description

Technical Field

[0001] The present invention particularly relates to an electrochemical discharge-laser-dynamic wet etching processing system, method and application, belonging to the technical field of special processing. Background Art

[0002] Hard and brittle materials that are difficult to process have the characteristics of high hardness, brittleness and anisotropy. When using traditional mechanical processing, it is easy to cause severe tool wear, and defects such as fiber breakage, pores, interface detachment, and cracks are prone to occur. Special processing technologies have been used to attempt to process hard and brittle materials that are difficult to process, such as water jet processing, laser processing, and electrochemical discharge processing. As non-contact processing, they can effectively overcome the limitations of mechanical processing. Water jet processing relies on jet impact to cause material fatigue fracture, thereby removing the material. There is no thermal stress and thermal deformation during the processing process, but when dealing with hard and brittle materials that are difficult to process, the load distribution is uneven due to hydraulic impact, which will produce obvious stratification. Laser processing applies energy locally on the surface of the material by focusing the beam to achieve precise material removal, and it is outstanding in micro-processing. However, it has obvious taper in the processing of deep small holes, and the processing accuracy needs to be improved. Electrospark processing can copy complex electrode shapes to the workpiece to form a very precise contour, but some hard and brittle materials that are difficult to process have weak conductivity and poor machinability.

[0003] In order to solve the problem of precision machining of non-conductive materials, electrochemical discharge machining was applied, but it is easy to have short circuit problems caused by poor chip removal when machining deep small holes, and the machining efficiency is low. CN104942388A discloses an apparatus and method for electrochemical discharge and laser composite processing of materials. In the immersion solution, the laser energy and the discharge energy act on the upper surface and the lower surface of the workpiece respectively, thereby increasing the etching rate of the workpiece material. For the hole-making process of hard and brittle materials that are difficult to machine, on the one hand, the immersion solution is still prone to the problem of poor chip removal, and on the other hand, the laser machining accuracy cannot be kept consistent with the electrochemical discharge machining accuracy, resulting in the hole shape being distorted at the junction of the two energy fields. In addition, hard and brittle materials that are difficult to machine, such as SiC / SiC composite materials, are prone to oxidation under high temperature conditions, thereby reducing the surface quality of the hole wall, which leads to limitations in laser machining and electrochemical discharge machining that remove materials by thermal effect.

[0004] Chemical etching can be used as a surface finishing process to improve the hard and brittle materials that are difficult to process by laser-electrochemical discharge composite machining. At the same time, the introduction of jet is also conducive to improving the chip removal ability during the machining process. How to effectively combine the comprehensive effects of laser machining, electrochemical discharge machining, chemical etching and jet to achieve a high-efficiency, high-precision, high-surface quality hole-making process for hard and brittle materials that are difficult to machine has very important engineering application value for the application and development of aviation manufacturing technology. Summary of the invention

[0005] The main purpose of the present invention is to provide an electrochemical discharge-laser-dynamic wet etching processing system, method and application, so as to overcome the deficiencies in the prior art.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0007] A first aspect of an embodiment of the present invention provides an electrochemical discharge-laser-dynamic wet etching composite processing system, which includes:

[0008] an electrochemical discharge machining module, which is used to perform electrochemical discharge machining on at least a first region of the workpiece to remove material from the first region of the workpiece;

[0009] A laser processing module, which is used to perform laser ablation processing on a second area of ​​the workpiece to remove material from the second area of ​​the workpiece, wherein the first area is distributed around the second area, and the first area and the second area are adjacent to each other;

[0010] A jet module, which is at least used to perform jet flushing on a processing area of ​​the workpiece, wherein the processing area includes the second area and the first area;

[0011] In which, the workpiece does not chemically react with the electrolyte used in the electrochemical discharge machining module, but the oxide formed by the oxidation of the workpiece can react chemically with the electrolyte and be removed. The oxide is formed by oxidation of the surface layer during the electrochemical discharge machining and / or laser ablation processing of the workpiece.

[0012] A second aspect of an embodiment of the present invention provides an electrochemical discharge-laser-dynamic wet etching composite processing method, which includes:

[0013] Immersing the workpiece in an electrolyte, and simultaneously performing electrochemical discharge machining on a first area of ​​the workpiece, laser ablation machining on a second area of ​​the workpiece, and jet flushing on a machining area of ​​the workpiece, wherein the machining area includes the second area and the first area, the first area is distributed around the second area, and the first area and the second area are adjacent to each other;

[0014] In which, the workpiece does not chemically react with the electrolyte used in the electrochemical discharge machining module, but the oxide formed by the oxidation of the workpiece can react chemically with the electrolyte and be removed. The oxide is formed by oxidation of the surface layer during the electrochemical discharge machining and / or laser ablation processing of the workpiece.

[0015] The third aspect of the embodiments of the present invention provides the use of the electrochemical discharge-laser-dynamic wet etching composite processing system or the electrochemical discharge-laser-dynamic wet etching composite processing method in drilling, cutting, milling and forming.

[0016] Compared with the prior art, the advantages of the present invention include:

[0017] (1) In the hole making process, as the hole depth increases, it is difficult for the processed product to be discharged from the gap, causing the processing to be interrupted. The jet from the electrode hole in the center of the tool electrode accelerates the discharge of the product, which is beneficial to increasing the processing speed. However, the center of the electrode hole is directly facing the workpiece material and cannot be etched away in time, resulting in a protrusion, which is easy to collide with the feeding electrode and cause a short circuit. The coaxial focused laser beam is focused at this location to melt the protruding material and also produces additional hydrogen. The embodiment of the present invention provides an electrochemical discharge-laser-dynamic wet etching processing system and method, which increases the discharge frequency, thereby ensuring a stable and efficient processing process.

[0018] (2) An embodiment of the present invention provides an electrochemical discharge-laser-dynamic wet etching processing system and method. The tool electrode used in electrochemical discharge processing generates discharge at the end face to remove material, while being insulated at the side wall, thereby avoiding secondary discharge with the side wall during product discharge and damaging the processed surface, thereby ensuring the consistency of the hole shape and improving the processing accuracy.

[0019] (3) An electrochemical discharge-laser-dynamic wet etching processing system and method provided in an embodiment of the present invention uses a chemical solution that has an etching effect on SiC oxide as an electrolyte for electrochemical discharge machining. On the one hand, it provides a gas environment for electrochemical discharge machining, and on the other hand, it simultaneously etches the oxide layer generated by the hole wall, thereby improving the surface quality of the inner wall of the hole.

[0020] (4) An electrochemical discharge-laser-dynamic wet etching processing system and method provided by an embodiment of the present invention has the synchronous action of electrochemical discharge, laser ablation and chemical etching. Therefore, the high temperature generated by electrochemical discharge and laser ablation will accelerate the etching rate of the oxide layer. The high temperature promotes the oxidation and etching effects at the same time, thereby producing selective etching of the oxide layer and improving the etching accuracy.

[0021] (5) An electrochemical discharge-laser-dynamic wet etching processing system and method provided by an embodiment of the present invention, wherein the jet remains coaxial with the tool electrode and the focused laser beam, and can continuously cool the processing area to reduce heat accumulation. In addition, it has a stronger flushing effect and can timely update the solution state of the processing area. While maintaining stable discharge, it inhibits debris and accumulated bubbles from absorbing laser energy and maintains a constant etching rate in the processing area.

[0022] (6) An embodiment of the present invention provides an electrochemical discharge-laser-dynamic wet etching processing system and method. The current detection module monitors the current and reflects the processing status in real time, which can provide a reference for the adjustment of subsequent process parameters and accurately grasp the drilling time. For example, after the film cooling hole processing of the turbine blade is completed, the tool is lifted to effectively prevent the laser from causing damage to the blade back. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of an electrochemical discharge-laser-dynamic wet etching composite pore making system provided in a typical implementation case of the present invention;

[0024] Figure 2 A schematic diagram of a typical embodiment of the present invention providing an electrochemical discharge-laser-dynamic wet etching composite hole making system for making holes in a SiC / SiC composite material workpiece;

[0025] Figure 3 , Figure 4 , Figure 5 , Figure 6 They are schematic diagrams of individual hole making by electrochemical discharge, laser ablation, chemical etching, and jet flushing processes;

[0026] Figure 7 It is a schematic diagram of the hole type evolution during electrochemical discharge machining, laser machining, and electrochemical discharge-laser composite machining;

[0027] Figure 8 This is a schematic diagram of the discharge enhancement effect of laser hydrogen production;

[0028] Fig. 9 , Fig.10 They are schematic diagrams of the processes of selective chemical etching and uniform chemical etching;

[0029] Fig.11 It is a schematic diagram of the improvement effect of jet flushing on electrochemical discharge-laser composite processing;

[0030] Fig.12 , Fig.13 , Fig.14 They are schematic diagrams of current feedback at different drilling moments;

[0031] Fig.15 , Fig.16 , Fig.17 , Fig.18 They are schematic diagrams of drilling, cutting, milling and forming by an electrochemical discharge-laser-dynamic wet etching composite processing system in a typical implementation case of the present invention. DETAILED DESCRIPTION

[0032] 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.

[0033] In a more typical implementation scheme, the present invention combines electrochemical discharge machining, laser machining, chemical etching and jet machining to simultaneously act on the hole-making process of hard-to-machine hard-to-machine brittle materials, thereby solving the problems of low material removal rate when machining deep small holes (holes with a depth-to-diameter ratio of 10 or more are called deep small holes) on hard-to-machine brittle material workpieces, inconsistent hole profiles when machining with lasers, and high-temperature oxidation of the hard-to-machine hard-to-machine materials easily caused by the thermal effects of the two processes.

[0034] An electrochemical discharge-laser-dynamic wet etching composite processing system provided in an embodiment of the present invention combines the high-precision advantage of electrochemical discharge machining, uses laser machining to improve machining efficiency, adopts dynamic chemical solution to selectively etch the oxide layer generated during the machining of hard and brittle materials that are difficult to machine, and timely updates the solution state, thereby forming a high-efficiency, high-precision, and high-surface quality machining solution.

[0035] An electrochemical discharge-laser-dynamic wet etching composite processing system provided in an embodiment of the present invention can realize the effective combination of electrochemical discharge machining, laser machining and dynamic wet etching by combining an electrochemical discharge machining system, a laser machining system, a chemical solution jet system and a current detection system, thereby laying a foundation for process equipment for forming an electrochemical discharge-laser-dynamic wet etching composite hole-making method with high efficiency, high precision and high surface quality.

[0036] A first aspect of an embodiment of the present invention provides an electrochemical discharge-laser-dynamic wet etching composite processing system, which includes:

[0037] an electrochemical discharge machining module, which is used to perform electrochemical discharge machining on at least a first region of the workpiece to remove material from the first region of the workpiece;

[0038] A laser processing module, which is used to perform laser ablation processing on a second area of ​​the workpiece to remove material from the second area of ​​the workpiece, wherein the first area is distributed around the second area, and the first area and the second area are adjacent to each other;

[0039] A jet module, which is at least used to perform jet flushing on a processing area of ​​the workpiece, wherein the processing area includes the second area and the first area;

[0040] In which, the workpiece does not chemically react with the electrolyte used in the electrochemical discharge machining module, but the oxide formed by the oxidation of the workpiece can react chemically with the electrolyte and be removed. The oxide is formed by oxidation of the surface layer during the electrochemical discharge machining and / or laser ablation processing of the workpiece.

[0041] Further, the electrochemical discharge machining module includes an electrolytic cell tank, a tool electrode and an auxiliary electrode, the electrolytic cell tank is used to contain an electrolyte, the tool electrode, the auxiliary electrode and the workpiece are arranged in the electrolytic cell tank and contact the electrolyte in the electrolytic cell tank, the tool electrode is a tubular electrode structure, the tool electrode has an electrode hole that penetrates along its own axis, the tube mouth of one end of the tool electrode faces the workpiece, when the auxiliary electrode and the tool electrode are powered by a power source, a discharge channel is induced between the end face of the tool electrode facing the workpiece and the workpiece, and the heat energy generated by the discharge channel is greater than the ablation threshold of the workpiece material;

[0042] The laser processing module comprises a laser, other optical path components and a focusing lens, wherein the other optical path components are arranged between the laser and the focusing lens, the laser beam emitted by the laser is guided by the other optical path components to enter the focusing lens, and is focused on the second area of ​​the workpiece by the focusing lens, and the power density of the focus of the laser beam is greater than the ablation threshold of the workpiece material;

[0043] The jet module includes a chemical solution supply component and a nozzle. The nozzle is communicated with the chemical solution supply component. The chemical solution provided by the chemical solution supply component is sprayed to the processing area of ​​the workpiece through the nozzle.

[0044] Furthermore, the focusing lens and the nozzle are sequentially arranged above the tool electrode along the axial direction of the tool electrode, the laser beam focused by the focusing lens is irradiated onto the workpiece along the electrode hole inside the tool electrode, and the chemical solution sprayed through the nozzle rushes out along the electrode hole inside the tool electrode.

[0045] Furthermore, the central axis of the tool electrode, the central axis of the electrode hole inside the tool electrode, the central axis of the nozzle, and the optical axis of the focusing lens coincide with each other, and the focused laser beam and the jet formed by the chemical solution are coaxial with the tool electrode.

[0046] Furthermore, the tool electrode includes a conductive metal and an insulating layer sequentially arranged from inside to outside along its radial direction, and the conductive metal encloses to form the electrode hole.

[0047] Furthermore, the laser processing module also includes a CCD camera, which emits a visible light beam, and the visible light beam passes through other optical path components and the focusing lens to form a positioning light beam with the same optical axis as the focused laser light beam.

[0048] Furthermore, the other optical path components include optical lenses and dichroic mirrors, etc.

[0049] Furthermore, the electrolyte is the same solution as the chemical solution used for jet flushing of the jet module, and the chemical solution supply component is also connected to the electrolytic cell, and a loop is formed between the chemical solution supply component, the nozzle, and the electrolytic cell for circulating the chemical solution.

[0050] In a more specific embodiment, the electrochemical discharge-laser-dynamic wet etching composite processing system also includes: a motion platform, at least the tool electrode, the nozzle and the focusing lens are arranged on the motion platform, and the motion platform is at least used to drive the tool electrode, the nozzle and the focusing lens to feed toward the workpiece.

[0051] Furthermore, the electrolytic cell is arranged on the motion platform, and the motion platform is also used to drive the electrolytic cell to move along the x-axis and the y-axis of the three-dimensional coordinate system.

[0052] Furthermore, the motion platform is a three-axis motion platform.

[0053] In a more specific embodiment, the electrochemical discharge-laser-dynamic wet etching composite processing system also includes: a current detection module, which is electrically connected to a power supply and is used to detect the current in a conductive path formed by the power supply and the tool electrode and the auxiliary electrode.

[0054] Furthermore, the current detection module includes an oscilloscope and a current probe, and the oscilloscope is electrically connected to the power supply via the current probe.

[0055] A second aspect of an embodiment of the present invention provides an electrochemical discharge-laser-dynamic wet etching composite processing method, which includes:

[0056] Immersing the workpiece in an electrolyte, and simultaneously performing electrochemical discharge machining on a first area of ​​the workpiece, laser ablation machining on a second area of ​​the workpiece, and jet flushing on a machining area of ​​the workpiece, wherein the machining area includes the second area and the first area, the first area is distributed around the second area, and the first area and the second area are adjacent to each other;

[0057] In which, the workpiece does not chemically react with the electrolyte used in the electrochemical discharge machining module, but the oxide formed by the oxidation of the workpiece can react chemically with the electrolyte and be removed. The oxide is formed by oxidation of the surface layer during the electrochemical discharge machining and / or laser ablation processing of the workpiece.

[0058] In a more specific embodiment, the electrochemical discharge-laser-dynamic wet etching composite processing method specifically includes:

[0059] Placing a workpiece, a tool electrode and an auxiliary electrode in an electrolyte, wherein the tool electrode is located above the workpiece, supplying power to the tool electrode and the auxiliary electrode, inducing a discharge channel between the tool electrode facing the end surface of the workpiece and the workpiece, and ablating and removing the material in the first region of the workpiece with heat energy generated by the discharge channel;

[0060] focusing a laser beam on a second region of the workpiece to ablate and remove material from the second region of the workpiece;

[0061] A chemical solution is sprayed toward the processing area of ​​the workpiece, and the processing area of ​​the workpiece is flushed with a jet formed by the chemical solution.

[0062] Furthermore, the tool electrode is a tubular electrode structure, the inside of the tool electrode has an electrode hole that penetrates along its own axial direction, the tube mouth of one end of the tool electrode faces the workpiece, and the method specifically includes: allowing the focused laser beam formed after focusing to irradiate the workpiece along the electrode hole, allowing the jet formed by the chemical solution to pass through the electrode hole and spray onto the workpiece, and the jet and the focused laser beam are coaxial with the tool electrode.

[0063] Furthermore, the electrolyte is the same solution as the chemical solution used for jet flushing.

[0064] Furthermore, the workpiece is a hard and brittle material that is difficult to machine. Specifically, the hard and brittle material that is difficult to machine includes materials containing SiC (such as SiC / SiC composite materials, etc.), titanium alloy materials, nickel-based high-temperature alloy materials, etc.

[0065] In a more specific embodiment, the electrochemical discharge-laser-dynamic wet etching composite processing method further includes: feeding the tool electrode and the focused laser beam toward the workpiece.

[0066] In a more specific embodiment, the electrochemical discharge-laser-dynamic wet etching composite processing method further includes: moving the electrolytic cell containing the electrolyte along the x-axis and the y-axis of the three-dimensional coordinate system.

[0067] In a more specific embodiment, the electrochemical discharge-laser-dynamic wet etching composite processing method further includes detecting the current in the conductive path formed by the power supply, the tool electrode, and the auxiliary electrode.

[0068] In a more specific implementation, the electrochemical discharge-laser-dynamic wet etching composite processing method is implemented based on the electrochemical discharge-laser-dynamic wet etching composite processing system.

[0069] The third aspect of the embodiments of the present invention provides the use of the electrochemical discharge-laser-dynamic wet etching composite processing system or the electrochemical discharge-laser-dynamic wet etching composite processing method in drilling, cutting, milling and forming.

[0070] 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 optical elements such as optical lenses, focusing lenses, dichroic mirrors, lasers, nozzles, auxiliary electrodes, power supplies, oscilloscopes, water chillers, computers, CCD cameras, water pumps, flow meters, rotary valves, filtering devices, three-axis motion tables, etc. used in the embodiments of the present invention are all known in the art and can be purchased commercially. Their specific structures and product models are not limited here.

[0071] In a more specific embodiment, an electrochemical discharge-laser-dynamic wet etching composite processing system includes an electrochemical discharge machining module, a laser machining module and a jet module, wherein the electrochemical discharge machining module is used to perform electrochemical discharge machining on a first area of ​​a workpiece to remove material from the first area of ​​the workpiece, the laser machining module is used to perform laser ablation processing on a second area of ​​the workpiece to remove material from the second area of ​​the workpiece, and the jet module is used to perform jet flushing on the processing area of ​​the workpiece, the processing area includes the second area and the first area, the first area is distributed around the second area, and the first area and the second area are adjacent, and the workpiece here is a hard and brittle material that is difficult to process, such as SiC / SiC composite materials.

[0072] For details, please refer to Figure 1The electrochemical discharge machining module includes an electrolytic cell tank 13, an auxiliary electrode 12, a tool electrode 30, a power supply 14 and an oscilloscope 15. The electrolytic cell tank 13 contains an electrolyte 8. The auxiliary electrode 12, the tool electrode 30 and the workpiece 10 are placed in the electrolytic cell tank 13 and in contact with the electrolyte 8. The tool electrode 30 is a tubular electrode structure. The tool electrode 30 has an electrode hole that penetrates along its own axial direction. The tool electrode 30 is arranged above the workpiece 10 along the z-axis of the three-dimensional coordinate system. The nozzle at one end of the tool electrode 30 faces the workpiece 10. The auxiliary electrode 12 and the tool electrode 30 are electrically connected to the positive electrode and the negative electrode of the power supply 14, respectively, and are configured together to form an electrolytic cell. The positive electrode and the negative electrode of the oscilloscope 15 are connected to the positive electrode and the negative electrode path of the power supply 14, respectively, for monitoring the machining current in the conductive path formed by the auxiliary electrode 12, the tool electrode 30 and the power supply 14.

[0073] The laser processing module includes a laser 18, a CCD camera 20, an optical lens 22, a dichroic mirror 23 and a focusing lens 1. The focusing lens 1 is arranged above the tool electrode 30 along the z-axis of the three-dimensional coordinate system. The output light beam 19 emitted by the laser 18 is reflected by the dichroic mirror 23 and focused by the focusing lens 1 to form a focused laser beam 2. The focused laser beam 2 passes through the electrode hole inside the tool electrode 30 and irradiates the workpiece 10. The focus of the focused laser beam 2 acts on the surface of the workpiece 10. The visible light beam 21 emitted by the CCD camera 20 passes through the optical lens 22, the dichroic mirror 23, the focusing lens 1 in sequence and irradiates the surface of the workpiece 10 through the electrode hole of the tool electrode 30 to calibrate the processing position of the focus of the focused laser beam 2.

[0074] The jet module includes a chemical solution supply component and a nozzle 4. The chemical solution supply component includes a water tank 24 and a water pump 25. The water tank 24, the water pump 25 and the nozzle 4 are connected in sequence through pipelines. The nozzle 4 is arranged between the tool electrode 30 and the lens 1 along the z-axis of the three-dimensional coordinate system. The chemical solution 7 in the water tank 24 is sprayed out through the nozzle 4 to form a jet. The jet sprayed by the nozzle 4 passes through the electrode hole inside the tool electrode 30 and acts on the workpiece 10.

[0075] For details, please refer to Figure 1 and Figure 2When the power supply 14 supplies power to the tool electrode 30 and the auxiliary electrode 12, a discharge channel 11 is induced near the tool electrode 30, thereby converting electrical energy into heat energy to erode the workpiece material (i.e., the material in the first area of ​​the workpiece) facing the end face of the tool electrode 30, and the discharge state is monitored in real time on the display screen of the oscilloscope 15; the focused laser beam 2 is focused on the surface of the workpiece 10 along the electrode hole inside the tool electrode 30, and the workpiece material (i.e., the material in the second area of ​​the workpiece) facing the electrode hole inside the tool electrode 30, and the jet provided by the jet module continuously flushes the processing area (the processing area includes the first area and the second area) along the electrode hole inside the tool electrode 30, and the processing product 7 is discharged by backflow, and the processing area is cooled, and the tool electrode 30, the jet and the focused laser beam 2 are continuously fed toward the workpiece 10, and the material removal process is circulated to gradually form a hole type.

[0076] Specifically, in order to realize the formation of deep small holes on the workpiece and to cooperate with the tool electrode 30, the jet and the focused laser beam 2 to continuously feed toward the workpiece 10, the electrochemical discharge machining module also includes a three-axis motion table, the tool electrode 30, the focusing lens 1 and the nozzle 4 are mounted on the z-axis slide 3 of the three-axis motion table, the tool electrode 30, the focused laser beam 2 and the jet can move synchronously along the z-axis, and the electrolytic cell 13 is mounted on the x-axis and y-axis translation tables ( Figure 1 Only the y-axis slide 34 is shown in the figure, and the electrolytic cell 13 can reciprocate along the x-axis and y-axis directions.

[0077] Specifically, the tool electrode 30 is preferably a circular tube electrode, and the central axis of the tool electrode 30, the central axis of the electrode hole, the central axis of the nozzle 4 and the optical axis of the focusing lens 1 are preferably coincident so that the jet is coaxial with the focused laser beam and the tool electrode. Specifically, the focused laser beam and the jet are located inside the tool electrode, and the focused laser beam is located inside the jet.

[0078] More specifically, the tool electrode 30 includes a conductive metal 5 and an insulating layer 6 arranged in sequence from the inside to the outside along its radial direction, and the conductive metal 5 encloses the electrode hole. The power supply 14 is specifically electrically connected to the conductive metal 5 of the tool electrode 30, wherein the insulating layer 6 of the tool electrode 30 prevents the secondary discharge between the processed product 7 and the tool electrode 30, thereby avoiding damage to the processed surface of the hole formed by the processing. Due to the thermal effect, an oxide layer 9 will be generated on the side wall of the hole, and the electrolyte 8 and the oxide layer 9 can react chemically to etch away the oxide layer 9, thereby obtaining a smooth hole wall. More specifically, the material of the conductive metal 5 inside the tool electrode 30 can be at least one of stainless steel, tungsten, brass, copper, and titanium alloy, but not limited thereto. Specifically, the material of the auxiliary electrode 12 can be at least one of graphite and calomel, but not limited thereto. Specifically, the material of the electrolytic cell 13 can be acrylic acid, etc. The power supply 14 can be a DC power supply.

[0079] Please refer again Figure 1 In order to prevent the tool electrode 30 from swinging during the machining process, the electrochemical discharge machining module can also include an electrode clamping device 28 and a guide sleeve 29. The guide sleeve 29 is fixed below the electrode clamping device 28 along the z-axis. The electrode clamping device 28 fixes and clamps the tool electrode 30. The part of the tool electrode 30 close to the workpiece 10 passes through the guide sleeve 29 and extends out from the guide sleeve 29.

[0080] For details, please refer to Figure 1 The laser processing module may further include a water cooler 16 and a computer 17. The water cooler 16 is thermally connected to the laser 18 and is used to cool the laser 18. The computer 17 is connected to the laser 18 and is used to adjust the working state / working parameters of the laser 18. Exemplarily, the laser 18 may be a nanosecond laser. The water cooler 16 and the computer 17 are both known in the art. The water cooler 16 may also be replaced by other functional mechanisms that can achieve temperature regulation of the laser, which is not specifically limited here. The numerical control program contained in the computer 17 is also known in the art.

[0081] Specifically, the chemical solution 7 and the electrolyte 8 used to form the jet can be the same solution, the solvent type and mass concentration of the chemical solution 7 and the electrolyte 8 are the same, the solvent of the chemical solution 7 and the electrolyte 8 can be at least one of NaOH, KOH, and HCl, and the mass concentration of the chemical solution 7 and the electrolyte 8 can be 50-200g / L. Please refer again Figure 1 The water tank 24 can be connected to the electrolytic cell 13, and a first flow meter 26 and a first switch valve 27 are also provided on the pipeline connecting the water pump 25 and the nozzle 4, and a filter device 33 is also provided between the water tank 24 and the electrolytic cell 13. The water tank 24, the electrolytic cell 13, and the filter device 33 are connected, and a second flow meter 31 and a second switch valve 32 are provided on the pipeline connecting the electrolytic cell 13 and the filter device 33, so that a loop is formed between the water tank 24 and the electrolytic cell 13 for circulating the chemical solution 7 / electrolyte 8. Specifically, the water pump 25 draws out the chemical solution 7 from the water tank 24, and adjusts the inlet flow through the first flow meter 26. The chemical solution 7 enters the nozzle 4 through the first switch valve 27, and then enters the electrode hole of the tool electrode 30, and is sprayed to the processing area of ​​the workpiece to form a jet flushing processing area. An opening is provided at the lower end of one side of the electrolytic cell 13, and a second flow meter 31 and a second switch valve 32 are connected by a pipeline. The electrolyte output from the electrolytic cell 13 enters the filter device 33 and impurities are filtered out, and then flows back to the water tank 24 for recycling, wherein the first switch valve 27 and the second switch valve 32 remain in a normally open state, and the first flow meter 26 and the second flow meter 31 adjust the inlet flow and the outlet flow to be consistent.

[0082] In a typical implementation case, the electrochemical discharge-laser-dynamic wet etching composite processing method using the aforementioned electrochemical discharge-laser-dynamic wet etching composite processing system specifically includes the following process:

[0083] (1) In the immersed electrolytic cell 13, after the power supply 14 supplies power to the tool electrode 30 and the auxiliary electrode 12, the electrolyte undergoes an electrochemical reaction around the tool electrode 30 and the auxiliary electrode 12, and a hydrogen evolution reaction occurs near the tool electrode 30 to produce hydrogen bubbles. The hydrogen bubbles gather to form an air film that wraps the tool electrode 30, and breakdown occurs after the electric field strength exceeds the air film, generating plasma. The plasma thermal energy is used to etch away the material in the first area of ​​the workpiece, thereby copying the shape of the tool electrode 30.

[0084] (2) The output beam 19 emitted by the laser 18 is reflected by the dichroic mirror 23 and focused above the nozzle 4 by the focusing lens 1 to form a focused laser beam 2. The focused laser beam 2 passes through the electrode hole inside the tool electrode 30 and irradiates the workpiece 10. The focus of the focused laser beam 2 acts on the surface of the workpiece 10 to melt the workpiece material directly opposite to the electrode hole of the tool electrode 30. It should be noted that the focal length of the focused laser beam 2 needs to be greater than the axial length of the tool electrode 30 to ensure that the focus of the focused laser beam 2 is located on the workpiece. Specifically, since it is necessary to ensure sufficient drilling depth, the length of the tool electrode 30 needs to be long enough, and the tool electrode 30 of at least 10 mm can simultaneously complete clamping and extend into the processing hole. The laser beam moves coaxially with the tool electrode 30, so it is focused above the tool electrode 30. Therefore, the length (focal length) of the focused laser beam 2 needs to be at least greater than the length of the tool electrode 30 to make the focus fall on the workpiece. On the basis of convenient clamping and processing, the length of the tool electrode 30 is selected to be relatively long, so it is recommended that the focal length exceeds 30 mm, preferably exceeds 100 mm.

[0085] (3) The chemical solution 7 pumped out from the water tank 24 passes through the nozzle 4 and rushes out along the electrode hole in the tool electrode 30 to form a jet coaxial with the tool electrode 30 and the focused laser beam 2, thereby limiting the range of the heat-affected zone generated by the laser and the discharge, and renewing the solution (i.e., the electrolyte) in the machining gap;

[0086] (4) The tool electrode 30 and the focused laser beam are simultaneously fed toward the workpiece 10 to gradually form a deep hole. The oscilloscope 15 continuously monitors the change of the machining current provided by the power supply 14. When the discharge current frequency is significantly reduced or there is no discharge current, the through hole machining is completed.

[0087] Specifically, the corresponding relationship between the machining current and the machining state is as follows: Figure 12-14As shown, the chip removal is good in the initial stage of drilling, and the oscilloscope shows that the discharge current frequency and peak value are low. As the processing depth increases, the poor chip removal leads to the deterioration of the discharge condition, and the discharge current peak value and frequency increase rapidly, and even continuous discharge waveforms appear. When the hole is penetrated, the debris is discharged from the bottom of the hole, and the discharge area decreases instantly until it disappears. What is shown on the current waveform is the rapid decrease in current frequency until there is no discharge current.

[0088] See also Figure 3 , Figure 3 The figure is a schematic diagram of hole making by electrochemical discharge process. In electrochemical discharge machining, the workpiece 10 and the auxiliary electrode 12 are immersed in the electrolyte 8. Under the action of the power supply 14, an electrochemical reaction occurs. An oxidation reaction occurs at the anode and a reduction reaction occurs at the cathode. The hydrogen ions in the water are attracted to the negative electrode to gain electrons and produce hydrogen, and the hydroxide ions are attracted to the negative electrode to lose electrons and produce oxygen. The exposed conductive metal end face of the cathode tool electrode 30 continuously produces hydrogen bubbles 35, which then gather into a gas film and are punctured under the action of a strong electric field to produce a plasma discharge channel 11. When the tool electrode 30 continues to approach the workpiece 10, the heat energy generated by the discharge channel 11 is used to melt or vaporize the material, and pits 36 are produced on the surface of the workpiece 10. The pits are stacked to form the final contour.

[0089] See also Figure 4 , Figure 4 It is a schematic diagram of laser ablation hole making. The energy density at the focus of the focused laser beam 2 is the highest. When the melting point or boiling point of the material is exceeded, the material is melted or vaporized. A pit 36 ​​similar to that formed by discharge etching is also generated at the focus.

[0090] See also Figure 5 , Figure 5 This is a schematic diagram of hole making by chemical etching process. Taking SiC / SiC composite material as an example, SiC / SiC composite material has strong chemical resistance and is not easy to corrode. However, SiC oxide formed by oxidation reaction under high temperature can react chemically with strong acid (such as hydrofluoric acid) or strong alkali (NaOH) to be corroded. In the etching solution, SiC / SiC composite material does not react with the etching solution, while oxide layer 9 is etched and dissolved. In order to reduce the damage of fluorine-containing substances to the environment and personnel, alkaline solution is given priority as etching solution.

[0091] See also Figure 6 , Figure 6 This is a schematic diagram of the hole making process by the jet flushing process. On the one hand, the role of the jet flushing is to flush the processing area to remove the processing products 7, reduce the probability of undesirable discharge, and inhibit the processing products 7 and accumulated bubbles from absorbing laser energy. On the other hand, the jet flushing can also cool the processing area and reduce the expansion of the heat-affected zone 37.

[0092] Figure 7Schematic diagram of hole type evolution of electrochemical discharge machining, laser machining, and electrochemical discharge-laser composite machining. In order to use the center jet scouring to obtain higher machining efficiency and surface quality, the conductive metal 5 inside the tool electrode 30 is opened. The probability of discharge at the hole opening position is very low, and the workpiece material in the area corresponding to the electrode hole is etched slowly. Therefore, a bulge is formed at the center position corresponding to the electrode hole of the workpiece and the workpiece electrode 30 (i.e., the aforementioned second area). When the tool electrode 30 continues to feed the workpiece 10, the conductive metal 5 is easy to collide with the bulge and short-circuit, resulting in machining interruption. In laser machining, as the machining depth increases, the difficulty of chip discharge increases, and the chip absorbs laser energy during the discharge process, resulting in the gradual attenuation of the laser energy acting on the workpiece 10 and the gradual increase of the hole machining taper. Even if layered scanning machining is used, the taper problem will occur. The electrochemical discharge-laser composite processing provided by the present invention utilizes the tool electrode 30 to process the workpiece material corresponding to the edge (periphery) of the electrode hole (i.e., the material of the first area of ​​the workpiece), and utilizes the laser to process the center material corresponding to the electrode hole (i.e., the material of the second area of ​​the workpiece), so that the electrothermal energy and the laser compensate for each other, thereby improving the processing efficiency and the contour accuracy of the hole.

[0093] Specifically, in the present invention, the focused laser beam and the jet are located inside the tool electrode, and the jet at the center of the tool electrode hole directly flushes the processing area to improve the chip removal ability, while the center hole of the tool electrode has no current density, so a central bulge will appear in the material when drilling (such as Figure 7 As shown), that is, energy loss, the focused laser beam can compensate for the energy loss in the center of the tool electrode and is used to eliminate the workpiece material facing the center hole of the tool electrode. Therefore, the tool electrode, focused laser beam, and jet coaxiality can simultaneously enhance chip removal and compensate for energy loss, making the hole processing process smoother.

[0094] Figure 8 Schematic diagram of laser hydrogen production to enhance discharge effect. In addition to the hydrogen evolution reaction at the tool electrode 30 serving as the cathode in the electrolytic cell 13, the focused laser beam 2 utilizes high temperature to decompose the water-based electrolyte 8 to generate hydrogen bubbles 35, which are generated just at the end surface of the tool electrode 30 facing the workpiece 10. More bubbles 35 accelerate the formation of the gas film, improve the discharge probability, and increase the efficiency of discharge etching of materials.

[0095] Fig. 9 , Fig.10Schematic diagrams of the process of selective chemical etching and uniform chemical etching, respectively. The heat energy generated by discharge and ablation is concentrated in the workpiece area facing the end face of the tool electrode 30. Therefore, relative to the oxide layer 9, the high temperature accelerates the chemical etching rate of the workpiece material facing the end face of the tool electrode 30, and the oxide layer 9 is quickly etched during the generation process, which in turn affects the formation of the oxide layer 9, that is, the oxide layer 9 is thinned by the first selective etching induced by high temperature, and then etched again in the immersed electrolyte 8. In addition, because the jet continuously flushes the processing area, the processing product 7 is quickly taken away, and the mass concentration of the electrolyte 8 is stabilized, making the etching effect more uniform.

[0096] Fig.11 The figure is a schematic diagram of the improvement effect of jet flushing on electrochemical discharge-laser composite processing. Jet flushing not only washes the processed product 7, but also takes away some discrete bubbles 35 that have not formed an air film, inhibiting their absorption of laser energy, and reducing the bridging of the processed product 7 and the discrete bubbles 35 in the narrow discharge gap to produce secondary discharge, which deteriorates the discharge state. In addition, jet flushing also has a deionization effect, compressing and interfering with the expansion of the plasma discharge channel 11 after etching the material, reducing the thermal damage to the material caused by excessive discharge.

[0097] Fig.12 , Fig.13 , Fig.14 Schematic diagrams of current feedback at different drilling moments. In the initial processing stage, discharge occurs between the conductive metal 5 and the workpiece 10, and the generated processed products 7 and bubbles 35 are easily discharged from the processing gap, so additional secondary discharges are rarely generated, and regular and small current fluctuations are displayed on the screen of the oscilloscope 15; when the tool electrode 30 is continuously fed and processed to a certain depth, the discharge stroke of the processed products 7 and bubbles 35 increases, that is, the residence time in the processing gap becomes longer, and the accumulated bubbles 35 and products 7 cause the discharge frequency to increase, the working condition deteriorates, and the oscilloscope 15 reflects more current fluctuations and higher current peaks at the same time; when the hole is penetrated, the pressure in the processing gap drops sharply, and the volume flow rate of the processed products 7 decreases instantly. The central jet can easily separate the newly generated bubbles 35 from the conductive metal 5, so discharge rarely occurs, and fewer low-peak current waveforms are displayed on the oscilloscope 15.

[0098] Fig.15 , Fig.16 , Fig.17 , Fig.18The schematic diagram of the application expansion of the electrochemical discharge-laser-dynamic wet etching composite processing technology provided by the present invention. The working conditions of drilling processing are the most complicated, and the processing gap is narrow. Especially after the drilling reaches a certain depth, it has an adverse effect on discharge, laser and chemical etching. By optimizing a large number of process parameters (the process parameters include: electrical parameters (voltage, frequency, duty cycle), laser parameters (single pulse energy, spot overlap rate), jet parameters (electrolyte type, ratio, jet pressure), etc.), after the drilling achieves a good processing effect, its process form can be expanded. For example, in cutting processing, the cutting processing uses the side discharge of the tool electrode 30 to remove material, so there is no need to set the insulating layer 6. For example, in milling processing, during side milling processing, the tool electrode 30 feeds the workpiece 10 along the y-axis, which is also side discharge. In order to avoid secondary damage to the surface of the milling groove by the electrode end face, an insulating layer 6 is set on the end face of the tool electrode 30. The significant advantage of discharge machining is that it can generate complex contours with high precision. A tool electrode 30 with complex shapes can be produced. An insulating layer 6 is provided on the outside of the electrode, and then the electrode shape is directly copied onto the workpiece 10 to form a complex contour. This is called forming processing.

[0099] It should be noted that the oxide layer formed on SiC / SiC composite materials during the processing can be etched away by an alkaline solution, and the oxide layer formed on hard and brittle materials such as titanium alloys and nickel-based high-temperature alloys during the processing can be etched by an electrolytic solution adapted thereto, that is, different electrolytic solutions are selected for the oxides formed on workpieces of different materials during the processing.

[0100] 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. An electrochemical discharge-laser-dynamic wet etching composite processing system, characterized in that: include: an electrochemical discharge machining module, which is used to perform electrochemical discharge machining on at least a first region of the workpiece to remove material from the first region of the workpiece; A laser processing module, which is used to perform laser ablation processing on a second area of ​​the workpiece to remove material from the second area of ​​the workpiece, wherein the first area is distributed around the second area, and the first area and the second area are adjacent to each other; A jet module, which is at least used to perform jet flushing on a processing area of ​​the workpiece, wherein the processing area includes the second area and the first area; In which, the workpiece does not chemically react with the electrolyte used in the electrochemical discharge machining module, but the oxide formed by the oxidation of the workpiece can react chemically with the electrolyte and be removed. The oxide is formed by oxidation of the surface layer during the electrochemical discharge machining and / or laser ablation processing of the workpiece.

2. The electrochemical discharge-laser-dynamic wet etching composite processing system according to claim 1, characterized in that: The electrochemical discharge machining module comprises an electrolytic cell tank (13), a tool electrode (30) and an auxiliary electrode (12); the electrolytic cell tank (13) is used to contain an electrolyte (8); the tool electrode (30), the auxiliary electrode (12) and the workpiece (10) are arranged in the electrolytic cell tank (13) and are in contact with the electrolyte (8) in the electrolytic cell tank (13); the tool electrode (30) is a tubular electrode structure; the tool electrode (30) has an electrode hole extending through the tool electrode (30) along its own axial direction; the tube mouth at one end of the tool electrode (30) faces the workpiece (10); when the auxiliary electrode (12) and the tool electrode (30) are powered by a power supply (14), a discharge channel (11) is induced between the end face of the tool electrode (30) facing the workpiece (10) and the workpiece (10); the heat energy generated by the discharge channel (11) is greater than the ablation threshold of the workpiece (10) material; The laser processing module comprises a laser (18), other optical path components and a focusing lens (1), wherein the other optical path components are arranged between the laser (18) and the focusing lens (1), the laser beam emitted by the laser (18) is guided by the other optical path components to enter the focusing lens (1), and is focused on a second area of ​​the workpiece (10) by the focusing lens (1), and the power density of the focus of the laser beam is greater than the ablation threshold of the material of the workpiece (10); The jet module comprises a chemical solution supply component and a nozzle (4), wherein the nozzle (4) is connected to the chemical solution supply component, and the chemical solution (7) provided by the chemical solution supply component is sprayed to the processing area of ​​the workpiece (10) through the nozzle (4).

3. The electrochemical discharge-laser-dynamic wet etching composite processing system according to claim 2, characterized in that: The focusing lens (1) and the nozzle (4) are sequentially arranged above the tool electrode (30) along the axial direction of the tool electrode (30); the laser beam focused by the focusing lens (1) is irradiated onto the workpiece (10) along the electrode hole inside the tool electrode (30); and the chemical solution (7) sprayed by the nozzle (4) is flushed out along the electrode hole inside the tool electrode (30); Preferably, the central axis of the tool electrode (30), the central axis of the electrode hole inside the tool electrode (30), the central axis of the nozzle (4), and the optical axis of the focusing lens (1) coincide with each other, and the focused laser beam and the jet formed by the chemical solution (7) are coaxial with the tool electrode (30).

4. The electrochemical discharge-laser-dynamic wet etching composite processing system according to claim 2 or 3, characterized in that: The tool electrode (30) comprises a conductive metal (5) and an insulating layer (6) arranged in sequence from the inside to the outside along its radial direction, and the conductive metal (5) encloses the electrode hole; And / or, the laser processing module further comprises a CCD camera, the CCD camera emits a visible light beam, and the visible light beam passes through other optical path components and the focusing lens (1) to form a positioning light beam with the same optical axis as the focused laser light beam; And / or, the chemical solution supply component is also connected to the electrolytic cell (13), and a loop for the chemical solution to circulate is formed between the chemical solution supply component, the nozzle (4) and the electrolytic cell (13), and the electrolyte and the chemical solution used for jet flushing of the jet module are the same solution.

5. The electrochemical discharge-laser-dynamic wet etching composite processing system according to claim 2, characterized in that: Also includes: A motion platform, at least the tool electrode (30), the nozzle (4) and the focusing lens (1) are arranged on the motion platform, and the motion platform is at least used to drive the tool electrode (30), the nozzle (4) and the focusing lens (1) to feed toward the workpiece; Preferably, the electrolytic cell (13) is arranged on the motion platform, and the motion platform is also used to drive the electrolytic cell (13) to move along the x-axis and y-axis of the three-dimensional coordinate system; Preferably, the motion platform is a three-axis motion platform.

6. The electrochemical discharge-laser-dynamic wet etching composite processing system according to claim 2, characterized in that: Also includes: a current detection module, the current detection module being electrically connected to a power source (14) and used for detecting a current in a conductive path formed by the power source (14), the tool electrode (30) and the auxiliary electrode (12); Preferably, the current detection module comprises an oscilloscope (15) and a current probe, and the oscilloscope (15) is electrically connected to the power supply (14) via the current probe.

7. An electrochemical discharge-laser-dynamic wet etching composite processing method, characterized in that: include: Immersing a workpiece (10) in an electrolyte (8), simultaneously performing electrochemical discharge machining on a first region of the workpiece (10), performing laser ablation machining on a second region of the workpiece (10), and performing jet flushing on a machining region of the workpiece (10), wherein the machining region includes the second region and the first region, the first region is distributed around the second region, and the first region and the second region are adjacent to each other; In which, the workpiece does not chemically react with the electrolyte used in the electrochemical discharge machining module, but the oxide formed by the oxidation of the workpiece can react chemically with the electrolyte and be removed. The oxide is formed by oxidation of the surface layer during the electrochemical discharge machining and / or laser ablation processing of the workpiece.

8. The electrochemical discharge-laser-dynamic wet etching composite processing method according to claim 7, characterized in that: include: A workpiece (10), a tool electrode (30) and an auxiliary electrode (12) are placed in an electrolyte (8), wherein the tool electrode (30) is located above the workpiece (10); a power source (14) is used to supply power to the tool electrode (30) and the auxiliary electrode (12); a discharge channel (11) is induced between the end surface of the tool electrode (30) facing the workpiece (10) and the workpiece (10); and the material in the first region of the workpiece (10) is ablated and removed by heat energy generated by the discharge channel (11); focusing a laser beam on a second region of the workpiece (10) to ablate and remove material from the second region of the workpiece (10); A chemical solution (7) is sprayed onto the processing area of ​​the workpiece (10), and the processing area of ​​the workpiece (10) is flushed with a jet formed by the chemical solution (7).

9. The electrochemical discharge-laser-dynamic wet etching composite processing method according to claim 8, characterized in that: The tool electrode (30) is a tubular electrode structure, and has an electrode hole extending through the tool electrode (30) along its own axial direction. The tube opening at one end of the tool electrode (30) faces the workpiece (10). And, the method specifically comprises: irradiating the focused laser beam formed after focusing onto the workpiece (10) along the electrode hole, allowing a jet formed by a chemical solution (7) to pass through the electrode hole and spray onto the workpiece (10), wherein the jet, the focused laser beam and the tool electrode (30) are coaxial; Preferably, the electrolyte (8) is the same solution as the chemical solution (7) used for jet flushing; Preferably, the workpiece (10) is a hard and brittle material that is difficult to machine; Preferably, the method further comprises: feeding the tool electrode and the focused laser beam toward the workpiece (10); Preferably, the method further comprises: moving the electrolytic cell (13) containing the electrolyte along the x-axis and the y-axis of the three-dimensional coordinate system; Preferably, the method further comprises detecting a current in a conductive path formed by the power source (14), the tool electrode (30) and the auxiliary electrode (12); Preferably, the electrochemical discharge-laser-dynamic wet etching composite processing method is implemented based on the electrochemical discharge-laser-dynamic wet etching composite processing system according to any one of claims 1 to 6.

10. Use of the electrochemical discharge-laser-dynamic wet etching composite processing system as described in any one of claims 1 to 6 or the electrochemical discharge-laser-dynamic wet etching composite processing method as described in claim 7, 8 or 9 in drilling, cutting, milling and forming.

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