Laser-assisted mask electrolysis combined machining method and machining system

Abstract

The invention discloses a laser-assisted mask electrolysis combined machining method and system. The machining system comprises a laser device, a laser beam, a focusing lens, an optical lens, an optical lens clamp body, a tool cathode, a tool cathode clamp, an electrolyte inlet, a workpiece clamp, an electrolysis power source, a workpiece, a mask, an electrolyte, an electrolyte outlet and an electrolyte outlet runner. A laser beam output by the laser sequentially penetrates through the focusing lens, the optical lens and the electrolyte from top to bottom and is vertically irradiated on the surface of the mask; the mask is tightly arranged on the upper end face of the workpiece; the workpiece is horizontally arranged under the optical lens; the lower end face of the tool cathode is higher than the upper end face of the optical lens. According to the method, the mask is broken and removed through the laser beams, the workpiece is etched and removed through in-situ electrolytic etching, then the recasting layer is removed through in-situ electrolytic etching, the machining locality is improved by means of the shielding effect of the mask, the machining stability is improved in a tool cathode and laser beam partitioning mode, and therefore efficient machining of the high-quality (Ralt and 1 micrometer) and micro-scale (lt and 100 micrometer) surface texture is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of special processing, and particularly relates to a laser-assisted mask electrolytic composite processing method and a processing system. BACKGROUND

[0002] Bearing is a core basic part in a mechanical system, and plays an irreplaceable role in high-end fields such as aviation, aerospace, energy and rail transportation. These fields have strict requirements on the performance of bearings: not only need to withstand high load, high speed and extreme temperature and other harsh working conditions, but also must have long service life, high reliability and low energy consumption and other comprehensive performance. Especially in key equipment such as aircraft engines, wind turbines and high-speed trains, the performance of bearings directly determines the running efficiency, reliability and safety of the entire system. Research shows that the performance, service life and reliability of bearings are closely related to their lubrication state, and statistics show that about 60% of bearing failures can be attributed to lubrication failure. Under extreme service conditions, the actual lubrication characteristics of bearings are significantly different from the ideal state, which often leads to excessive wear and then causes bearing failure. With the rapid development of surface and interface science and technology, domestic and foreign scholars have found through systematic research that the tribological performance of a surface is not a simple linear relationship with the surface roughness, but there is an optimal surface topography feature. Research shows that surfaces with specific micro-texture morphology often exhibit superior tribological performance.

[0003] Surface micro-texture technology refers to the processing of a micro-nano structure array with specific geometric parameters and spatial distribution rules on the surface of a material. This structure can effectively regulate the contact state and lubrication characteristics of the surface of a friction pair by changing the topological morphology of the material surface, thereby significantly improving the tribological performance of the friction pair. At present, micro-texture processing technology has been successfully applied in the fields of cylinder sleeve-piston ring, bearing, gear, cutter and sealing ring. However, the existing technology still has many limitations: conventional laser processing and electric spark processing will produce recast layer defects; although ultrafast laser processing can avoid recast layer structure, the equipment is expensive and the processing cost is high; electrolytic processing surface also has no recast layer defects, but the processing efficiency is low; mechanical processing is easy to produce burrs, micro-cracks and residual stress; and photolithography method has the disadvantages of complex process and environmental pollution.

[0004] As a typical composite machining technology, laser-electrolytic composite machining technology has high machining efficiency of laser machining and excellent surface quality of electrolytic machining, and is a research hotspot in the field of advanced manufacturing. After years of development, the machining principle and material removal mechanism of laser-electrolytic composite machining technology have been gradually improved, and it has been successfully applied to the machining of high-quality precision pits, small holes and groove structures. However, the existing technology still has many limitations: such as the problems of water jump and laser spot drift in the machining process of laser-assisted jet electrolytic machining technology [ZL200610041595.0], which makes it difficult to accurately control the machining stability and machining precision. Although the coaxial double-layer tube electrode laser-electrolytic composite machining technology [ZL202111682641.6] can achieve high machining stability and efficiency, the laser thermal effect is significant, which leads to a higher roughness of the machined micro-textured surface. Some scholars choose light-transmitting conductive glass as a tool electrode [ZL202310912628.8], which cleverly solves the problem of considering laser beam transmission and electrolytic circuit conduction, but the light-transmitting conductive glass has poor durability and its conductive performance may be lost after multiple uses. The current deficiencies weaken the advantages of laser-electrolytic composite machining technology in efficient and high-quality machining. In addition, due to the size limitation of the tool electrode (such as the coaxial double-layer tube electrode), the existing technology can only be used for machining of millimeter-scale surface texture, and it is difficult to meet the machining needs of micron-scale (<100 μm) surface texture. Therefore, it is necessary to develop a micro-scale texture machining system and method that takes into account machining quality and efficiency, and has a simple process, in order to solve the above problems. SUMMARY

[0005] To solve the problems existing in the prior art, the purpose of the present application is to provide a laser-assisted mask electrolytic composite machining method and machining system, in order to realize the purpose of high-quality (Ra<1 μm), micro-scale (<100 μm) surface texture efficient and low-cost machining.

[0006] The technical scheme adopted by the present application is: a laser-assisted mask electrolytic composite machining method, the steps are as follows: S1, the workpiece with a surface attached mask is horizontally arranged below the optical lens, the vertical distance between the optical lens and the workpiece is adjusted to a set value by the optical lens clamp body; turn on the electrolyte switch, the electrolyte enters the machining area from the electrolyte inlet, flows through the workpiece, the optical lens and the tool cathode in turn, and flows out from the electrolyte outlet; then turn on the electrolysis power supply, since the workpiece surface is covered with an electrically insulating mask, the workpiece-electrolyte-tool cathode circuit is blocked by the mask; S2, the laser switch is turned on, the laser beam passes through the focusing lens, the optical lens and the electrolyte in turn, and irradiates on the mask surface vertically, the mask is removed by the laser irradiation; the exposed part of the workpiece surface is etched and a recast layer is generated under the action of the laser beam; the products and bubbles in the processing process are quickly taken away from the processing area under the flushing of the electrolyte; S3, when the workpiece surface is exposed to the electrolyte, the workpiece-electrolyte-tool cathode loop is turned on, at this time the recast layer and the exposed part of the workpiece are dissolved and removed under the action of electrolysis; S4, as the laser beam processes according to the preset scanning path and process parameters, the mask on the workpiece surface is selectively removed, and then the workpiece surface exposed to the electrolyte is etched under the combined action of laser thermal corrosion and electrochemical corrosion, and finally the preset micro-texture pattern is obtained.

[0007] The scheme also contains a processing system for laser-assisted mask electrolytic composite machining method, including laser, focusing lens, optical lens, optical lens clamp, tool cathode, tool cathode clamp, electrolyte inlet, workpiece clamp, electrolysis power supply, electrolyte, electrolyte outlet and electrolyte outlet flow channel; the laser beam output by the laser passes through the focusing lens, the optical lens and the electrolyte in turn, and irradiates on the mask attached to the workpiece surface vertically, the upper end surface of the workpiece is parallel to the lower end surface of the optical lens; the optical lens is horizontally arranged on the inner surface of the optical lens clamp and the center axes of the two coincide; the tool cathode is horizontally arranged in the electrolyte outlet flow channel, and the lower end surface of the tool cathode is higher than the upper end surface of the optical lens; the center axes of the electrolyte inlet and the electrolyte outlet are perpendicular, and the height of the electrolyte inlet is lower than the height of the electrolyte outlet; under the condition that the electrolyte switch is turned on, the electrolyte enters the processing area from the electrolyte inlet, flows through the workpiece, the optical lens, the tool cathode, the electrolyte outlet flow channel in turn, and flows out from the electrolyte outlet; the positive and negative electrodes of the electrolysis power supply are connected with the workpiece and the tool cathode respectively.

[0008] As a preferred scheme, the tool cathode is a metal mesh or foam metal with excellent conductivity and acid and alkali corrosion resistance, the thickness is 0.5-2mm, and the mesh hole diameter is 0.05-2mm.

[0009] As a preferred scheme, the laser is an ultraviolet, green or infrared nanosecond pulse solid laser, and the laser output power is adjustable between 0-30W.

[0010] As a preferred scheme, the optical lens is an optical glass with high transmittance, low refractive index and low absorption rate for ultraviolet, green or infrared light.

[0011] As a preferred scheme, the spot diameter of the laser beam irradiated on the workpiece surface after passing through the focusing lens, the optical lens and the electrolyte is less than 0.1mm.

[0012] As a preferred solution, the mask is a polymer film with electrical insulation and low melting point, and the thickness is 0.01-0.1mm.

[0013] As a preferred solution, the distance between the lower end surface of the optical lens and the upper end surface of the workpiece is 1-4mm.

[0014] As a preferred solution, the diameter of the tool cathode is larger than the diameter of the optical lens, and the diameter of the optical lens is larger than the diameter or length of the workpiece.

[0015] As a preferred solution, the electrolytic power supply is a direct current or direct current pulse power supply, and the voltage range is 0-50V, and the frequency is 0-100kHz.

[0016] The beneficial effects of the present application are: Based on the defects existing in the prior art, the present application provides a laser-assisted mask electrolytic composite machining method and machining system, which can achieve the following technical effects through optimization of the machining process and the structure of the equipment used: Firstly, the present application can obtain excellent machining surface quality. The recast layer and heat-affected zone generated by laser machining can be completely removed in situ under the action of electrolysis, significantly reducing the roughness and improving the machining surface quality. At the same time, the photoactivation effect of the laser can activate the material surface, further improving the etching uniformity and consistency of the machining surface. In addition, the insulating coating can shield the electric field in the non-machining area, and the electrolysis effect on the workpiece surface is restricted to the mask breaking area (i.e. the micro-texture pattern area), effectively solving the problem of stray corrosion in electrolytic machining.

[0017] Secondly, the present application has high machining stability. Compared with the conventional laser-electrolytic composite machining system, the present application innovatively divides the tool cathode and the laser beam, and by setting the cathode at the electrolyte outlet channel, the cathode bubbles quickly flow out of the electrolyte outlet, avoiding the interference of the cathode bubbles with the laser beam, and improving the machining stability of the composite process.

[0018] Thirdly, the present application has high machining efficiency. The workpiece material is quickly etched and forms a preliminary texture morphology under the action of high temperature and high pressure of the laser, and then the recast layer and heat-affected zone are effectively eliminated under the action of electrochemical dissolution. Although the machining efficiency may be slightly lower than that of single conventional laser machining, it is significantly higher than that of ultrafast laser machining and conventional electrolytic machining. Moreover, laser-assisted mask electrolytic composite machining is a one-time forming process, without the need for additional post-processing, and the overall efficiency is higher than that of conventional laser machining which requires post-processing.

[0019] Fourthly, the present application has high process flexibility. It can be applied to bearing surface processing requirements of different materials, different geometrical shapes and different sizes. By optimizing laser and electrolysis parameters, the morphology, size and distribution of the surface texture can be accurately controlled to meet the needs of diversified application scenarios. In addition, compared with other high-quality (Ra<1 μm) and micro-scale (<100 μm) surface texture processing technologies (such as ultrafast laser processing, photolithography process, etc.), the present application significantly reduces the processing cost and has higher economic efficiency.

[0020] Fifthly, the present application processes metal surface micro-texture in solution. The under-liquid processing environment not only improves the processing quality, but also reduces dust and harmful gas generated in the processing process, which is environmentally friendly. The selection and recycling of neutral electrolyte further reduce the processing cost and meet the development trend of green manufacturing. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Fig. 1 A laser-assisted mask electrolytic composite machining system structure schematic diagram is provided for the embodiments of the present application. Fig. 2 A spatial position schematic diagram of tool cathode, optical lens and workpiece is provided for the embodiments of the present application. Fig. 3 A laser-assisted mask electrolytic composite machining method flow chart is provided for the embodiments of the present application. The drawings show that: 1, laser; 2, laser beam; 3, focusing lens; 4, optical lens; 5, optical lens clamp; 6, tool cathode; 7, tool cathode clamp; 8, electrolyte inlet; 9, workpiece clamp; 10, electrolysis power supply; 11, workpiece; 12, mask; 13, electrolyte; 14, electrolyte outlet; 15, cathode bubble; 16, electrolyte outlet flow channel; 17, vapor bubble; 18, recast layer; 19, laser processing product; 20, mask debris; 21, electrolytic processing product; 22, micro groove. DETAILED DESCRIPTION

[0023] In the following, the present application will be specifically described through exemplary embodiments. However, it should be understood that the elements, structures and features in one embodiment can also be beneficially combined into other embodiments without further description.

[0024] It should be noted that: unless otherwise defined, the technical terms or scientific terms used herein should be understood as the usual meaning understood by those skilled in the art to which the present application belongs; the "one", "a" or "the" and similar words used in the patent application description and claims of the present application do not represent quantity limitation, but indicate the existence of at least one; "includes" or "contains" and similar words indicate that the elements or objects appearing before "includes" or "contains" cover the elements or objects listed after "includes" or "contains" and their equivalents, but do not exclude other elements or objects with the same function; The specific structure and composition of the laser-assisted mask electrolytic composite machining system and the detailed process of the machining method are described as follows: Figs. 1-3 The specific structure and composition of the laser-assisted mask electrolytic composite machining system and the detailed process of the machining method are described as follows: As shown in the figure, a laser-assisted mask electrolytic composite machining system comprises a laser 1, a laser beam 2, a focusing lens 3, an optical lens 4, an optical lens clamp 5, a tool cathode 6, a tool cathode clamp 7, an electrolyte inlet 8, a workpiece clamp 9, an electrolysis power supply 10, a workpiece 11, a mask 12, an electrolyte 13, an electrolyte outlet 14 and an electrolyte outlet flow channel 16; the laser beam 2 output by the laser 1 passes through the focusing lens 3, the optical lens 4 and the electrolyte 13 from top to bottom in turn, and irradiates vertically on the surface of the mask 12; the mask 12 is closely arranged on the upper end surface of the workpiece 11; the workpiece 11 is horizontally arranged directly below the optical lens 4, and the upper end surface of the workpiece 11 is parallel to the lower end surface of the optical lens 4; the optical lens 4 is horizontally arranged on the inner surface of the optical lens clamp 5, and the central axes of the two coincide; the tool cathode 6 is horizontally arranged in the electrolyte outlet flow channel 16, and the lower end surface of the tool cathode 6 is higher than the upper end surface of the optical lens 4; the central axes of the electrolyte inlet 8 and the electrolyte outlet 14 are perpendicular, and the height of the electrolyte inlet 8 is lower than the height of the electrolyte outlet 14; under the condition that the electrolyte switch is turned on, the electrolyte 13 enters the machining area from the electrolyte inlet 8, flows through the workpiece 11, the optical lens 4, the tool cathode 6 and the electrolyte outlet flow channel 16 in turn, and flows out from the electrolyte outlet 14; the positive and negative electrodes of the electrolysis power supply 10 are connected to the workpiece 11 and the tool cathode 6 respectively.

[0025] In this embodiment, the tool cathode 6 is a titanium mesh with excellent electrical conductivity and acid and alkali corrosion resistance, and the thickness is 1 mm and the mesh hole diameter is 0.2 mm.

[0026] In this embodiment, the laser 1 is an ultraviolet nanosecond pulse solid-state laser, and the laser output power is 10 W.

[0027] In this embodiment, the optical lens 4 is a quartz glass with high transmittance, low refractive index and low absorption rate for ultraviolet light.

[0028] In this embodiment, the laser beam 2 irradiates on the workpiece 11 surface through the focusing lens 3, optical lens 4 and electrolyte 13, and the spot diameter is 0.05mm.

[0029] In this embodiment, the mask 12 is a resin material with electrical insulation and low melting point, and the thickness is 0.03mm.

[0030] In this embodiment, the distance between the lower end surface of the optical lens 4 and the upper end surface of the workpiece 11 is 2mm.

[0031] In this embodiment, the inner and outer diameter of the tool cathode 6 are 70mm and 50mm respectively, and the diameter of the optical lens 4 and the workpiece 11 are 40mm and 30mm respectively.

[0032] In this embodiment, the electrolysis power supply 10 is a direct current pulse power supply, and the voltage is set to 20V and the frequency is 1000Hz.

[0033] A laser-assisted mask electrolytic composite machining method, comprising the following steps: Step one, first, the workpiece 11 with surface attached mask 12 is horizontally arranged directly below the optical lens 4, and the vertical distance between the optical lens 4 and the workpiece 11 is adjusted to 2mm by the optical lens clamp body 5; turn on the electrolyte switch, and the electrolyte 13 enters the machining area at a flow rate of 20L / H from the electrolyte inlet 8, flows through the workpiece 11, the optical lens 4, the tool cathode 6 and the electrolyte outlet flow channel 16 in turn, and flows out from the electrolyte outlet 14; then, the voltage and frequency of the electrolysis power supply 10 are set to 20V and 1000Hz respectively, and the electrolysis power supply 10 is turned on, because the workpiece 11 surface is covered with an electrically insulating mask 12, the workpiece-electrolyte-tool cathode circuit is blocked by the mask 12, and at this time the electrochemical dissolution phenomenon does not occur; Step two, the output power, scanning speed and number of times of reaching the standard of the laser 1 are set to 10W, 50mm / s and 10 respectively, the laser switch is turned on, the laser beam 2 passes through the focusing lens 3, the optical lens 4 and the electrolyte 13 in turn, and is vertically irradiated on the surface of the mask 12, at this time the mask 12 is quickly broken and removed under the action of laser irradiation; then, the workpiece 11 is exposed and etched and a recast layer 18 is generated under the action of high temperature and high pressure of the laser beam 2, and at the same time the laser processing product 19, the vapor bubble 17 and the mask debris 20 are quickly taken away from the machining area under the scouring of the electrolyte 13; Step three, when part of the surface of the workpiece 11 is exposed to the electrolyte 13, the workpiece-electrolyte-tool cathode circuit is conducted, and the electrolysis phenomenon occurs immediately, at this time the recast layer 18 and the exposed part of the workpiece 11 are dissolved and removed under the action of electrolysis, and the electrolysis product 21 is quickly taken away from the machining area by the flowing electrolyte, and at the same time the cathode bubble 15 located in the electrolyte outlet channel 16 also flows out quickly with the electrolyte 13; Step four, with the laser beam 2 processing according to the preset scanning path and process parameters, the mask 12 on the surface of the workpiece 11 is selectively broken, and the surface of the workpiece 11 exposed in the electrolyte 13 is efficiently and high-qualityly etched under the combined action of laser thermal corrosion and electrochemical corrosion, and finally an S-shaped micro groove 22 with a width of 0.08 mm, a depth of 0.03 mm, and a length of 5 mm is processed, the roughness of the processed surface is 0.6 μm, the laser 1 and the electrolysis power supply 10 are turned off, the electrolyte switch is disconnected, the workpiece 11 is unloaded and cleaned, and the processing is completed.

[0034] The parts of the above embodiments not described in detail are prior art.

[0035] It should be noted that although the present application has been described by the above embodiments, the present application can also have other various embodiments. Those skilled in the art can obviously make various corresponding changes and modifications to the present application without departing from the spirit and scope of the present application, but these changes and modifications should belong to the scope of protection of the appended claims and their equivalents of the present application.

Claims

1. A laser-assisted mask-electrolytic composite processing method, characterized in that: The steps are as follows: S1. Place the workpiece with the mask attached to its surface horizontally directly below the optical lens. Adjust the vertical distance between the optical lens and the workpiece to the set value using the optical lens clamp. Turn on the electrolyte switch. The electrolyte enters the processing area from the electrolyte inlet, flows through the workpiece, the optical lens, and the tool cathode in sequence, and flows out from the electrolyte outlet. Then the electrolysis power supply is turned on. Because the workpiece surface is covered with an electrically insulating mask, the workpiece-electrolyte-tool cathode circuit is blocked by the mask. S2. Turn on the laser switch. The laser beam passes through the focusing lens, optical lens and electrolyte in sequence, and irradiates the mask surface vertically. The mask is quickly broken and removed under the laser irradiation. Part of the workpiece surface is exposed and etched away under the action of the laser beam to produce a recast layer. The products and bubbles of the processing are quickly carried away from the processing area by the electrolyte. S3. When the workpiece surface is exposed to the electrolyte, the workpiece-electrolyte-tool cathode circuit is connected, and the recast layer and the exposed part of the workpiece are dissolved and removed under the action of electrolysis. S4. As the laser beam processes the workpiece according to the preset scanning path and process parameters, the mask on the workpiece surface is selectively broken. Subsequently, the workpiece surface exposed to the electrolyte is etched away under the combined action of laser thermal corrosion and electrochemical corrosion, and finally the preset micro-texture pattern is obtained.

2. The processing system used in the laser-assisted mask-electrolytic composite processing method according to claim 1, characterized in that: The assembly includes a laser (1), a focusing lens (3), an optical lens (4), an optical lens fixture (5), a tool cathode (6), a tool cathode fixture (7), an electrolyte inlet (8), a workpiece fixture (9), an electrolytic power supply (10), an electrolyte (13), an electrolyte outlet (14), and an electrolyte outlet channel (16). The laser beam (2) output by the laser (1) passes through the focusing lens (3), the optical lens (4), and the electrolyte (13) in sequence, and irradiates vertically onto the mask (12) attached to the surface of the workpiece (11). The upper end face of the workpiece (11) is parallel to the lower end face of the optical lens (4). The optical lens (4) is horizontally mounted on the inner surface of the optical lens fixture (5), and the central axes of the two are aligned. The phases coincide; the tool cathode (6) is horizontally installed in the electrolyte outlet channel (16), and the lower end face of the tool cathode (6) is higher than the upper end face of the optical lens (4); the central axis of the electrolyte inlet (8) is perpendicular to the central axis of the electrolyte outlet (14), and the height of the electrolyte inlet (8) is lower than the height of the electrolyte outlet (14). When the electrolyte switch is turned on, the electrolyte (13) enters the processing area from the electrolyte inlet (8), flows through the workpiece (11), optical lens (4), tool cathode (6), and electrolyte outlet channel (16) in sequence, and flows out from the electrolyte outlet (14); the positive and negative terminals of the electrolytic power supply (10) are connected to the workpiece (11) and the tool cathode (6) respectively.

3. The processing system according to claim 2, characterized in that: The tool cathode (6) is a metal mesh or foam metal with excellent conductivity and resistance to acid and alkali corrosion, with a thickness of 0.5-2 mm and a mesh diameter of 0.05-2 mm.

4. The processing system according to claim 2, characterized in that: The laser (1) is a nanosecond pulse solid-state laser with ultraviolet, green or infrared light, and the laser output power is adjustable from 0 to 30W.

5. The processing system according to claim 2, characterized in that: The optical lens (4) is an optical glass with high transmittance, low refractive index and low absorption rate for ultraviolet light, green light or infrared light.

6. The processing system according to claim 2, characterized in that: The laser beam (2) irradiates the surface of the workpiece (11) through the focusing lens (3), optical lens (4) and electrolyte (13) with a spot diameter of less than 0.1 mm.

7. The processing system according to claim 2, characterized in that: The mask (12) is an electrically insulating, low-melting-point polymer film with a thickness of 0.01-0.1 mm.

8. The processing system according to claim 2, characterized in that: The distance between the lower end face of the optical lens (4) and the upper end face of the workpiece (11) is 1-4 mm.

9. The processing system according to claim 2, characterized in that: The diameter of the tool cathode (6) is larger than the diameter of the optical lens (4), and the diameter of the optical lens (4) is larger than the diameter or length of the workpiece (11).

10. The processing system according to claim 2, characterized in that: The electrolytic power supply (10) is a DC current or DC pulse power supply with a voltage range of 0-50V and a frequency of 0-100kHz.

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