A laser and electrochemical composite machining device

Abstract

The present invention provides a laser and electrochemical composite processing device, which includes an optical unit, an electrochemical reaction unit and a fluid control unit; the optical unit includes a nanosecond green laser, an XY two-axis laser scanning galvanometer, a focusing lens and a control system; the electrochemical reaction unit includes a copper sheet, a cathode, a metal anode workpiece, a reaction vessel, an electrolyte, a wire, a DC power supply, a base and a liquid storage tank; both the reaction vessel and the liquid storage tank are transparent acrylic containers; the laser beam output by the nanosecond green laser passes through the XY two-axis laser scanning galvanometer and the focusing lens, and then passes through the transparent liquid storage tank, the reaction vessel and the transparent cathode, and finally focuses on the surface of the metal anode workpiece. The present invention uses a transparent electrode to replace the traditional metal electrode. After the laser beam is output through the galvanometer scanning and the focusing lens, it passes through the transparent electrode and irradiates the metal surface to be processed, and can realize the high-efficiency and high-precision processing of large areas and arbitrary patterns on the metal surface by the laser and electrochemical composite etching process.

Description

Technical Field

[0001] The present invention belongs to the field of laser processing, and particularly relates to a laser-electrochemical composite processing device. Background Art

[0002] With the progress of science and technology and the development of the economy, higher requirements are put forward for the processing and manufacturing technology of products. In the field of calibration and scribing of parts, laser processing has many advantages such as non-contact, pollution-free and high efficiency compared with traditional processing methods. However, the laser processing process is prone to the generation of recast layers, burrs and microcracks, which affect the processing quality.

[0003] Electrochemical machining is a non-contact machining method that uses the principle of anodic dissolution of metals to remove materials and can achieve extremely high-quality machining. However, the passivation film is easily generated during the machining process, resulting in low machining efficiency. It can be seen that a single machining process is difficult to achieve compatibility in terms of machining ability, machining efficiency and surface quality.

[0004] The laser-electrochemical composite machining technology combines the advantages of high laser machining efficiency and good surface quality of electrochemical machining, and has become a high-precision machining technology with high surface quality that has attracted extensive attention at home and abroad. However, at present, the laser-electrochemical composite machining technology mainly realizes the machining of micro-holes by introducing electrolyte and laser into a hollow tube electrode with a diameter of 0.3-1 mm. Its machining area is small, the efficiency is low, and the degree of flexibility is low, and it is impossible to realize the efficient machining of large-area patterns. Summary of the Invention

[0005] Aiming at the deficiencies existing in the prior art, the present invention provides a laser-electrochemical composite machining device with high machining efficiency and a large machining area.

[0006] The present invention is realized by the following technical solutions:

[0007] A laser and electrochemical composite machining device includes an optical unit, an electrochemical reaction unit, and a fluid control unit; characterized in that the optical unit includes a nanosecond green laser, an XY two-axis laser scanning galvanometer, a focusing lens, and a control system; the electrochemical reaction unit includes a copper sheet, a cathode, a metal anode workpiece, a reaction vessel, an electrolyte, a wire, a DC power supply, a base, and a liquid storage tank; both the reaction vessel and the liquid storage tank are transparent acrylic vessels with a light transmittance greater than 90%; the reaction vessel is vertically and fixedly placed above the base, and both the reaction vessel and the base are arranged in the liquid storage tank; two grooves are opened at the bottom of the reaction vessel, and a slit is arranged between the two grooves; the cathode and the metal anode workpiece are both vertically placed in the two grooves and fixedly clamped, and the two are respectively connected to the negative and positive poles of the DC power supply through wires; the electrolyte is sprayed into the space between the cathode and the metal anode workpiece through the slit, and the cathode is a transparent indium tin oxide conductive glass; the laser beam output by the nanosecond green laser passes through the XY two-axis laser scanning galvanometer and the focusing lens, and then passes through the transparent liquid storage tank, reaction vessel, and cathode, and is focused on the surface of the metal anode workpiece.

[0008] Further, the fluid control unit includes a pipeline, a check valve, a filter, a micro pump, a main container, and a nozzle; the main container is used to hold the electrolyte, the inlet end of the micro pump is communicated with the main container, and the outlet end of the micro pump passes through the filter and then passes through the inlet of the liquid storage tank and the inlet of the base, and is injected into the nozzle arranged in the internal cavity of the base; the nozzle is installed in the internal cavity of the base, and the outlet of the nozzle is communicated with the slit at the bottom of the reaction vessel for spraying the electrolyte into the slit at the bottom of the reaction vessel; the electrolyte in the liquid storage tank flows back into the main container through its outlet and the pipeline, and a check valve for preventing the solution from flowing back is arranged on the pipeline.

[0009] Further, the fluid control unit further includes an ultrasonic vibration platform, and the ultrasonic vibration platform is installed at the bottom of the liquid storage tank for removing bubbles, reaction products, and impurities generated by the electrochemical reaction through ultrasonic vibration.

[0010] The present invention has the following beneficial effects:

[0011] 1. The laser and electrochemical composite machining device of the present invention uses a transparent electrode instead of a traditional metal electrode, enabling the laser to directly penetrate the electrode and irradiate the surface of the metal to be machined, successfully realizing the effective combination of laser ablation and flat electrode electrochemical etching.

[0012] 2. During the laser and electrochemical composite machining process, the laser can be driven by the galvanometer to move to realize the machining of large-area arbitrary patterns, overcoming the problem of too small machining area of traditional tube electrode-based composite machining. At the same time, increasing the laser scanning speed can match higher laser energy, thereby realizing the efficient removal of materials and overcoming the problem of too low machining efficiency of traditional tube electrode-based composite machining.

[0013] 3. During the laser-electrochemical composite machining process of the present invention, the laser can not only effectively remove the passivation film that hinders the electrochemical reaction and promote the efficiency of the electrochemical reaction, but also the heat energy generated by the laser acting on the material can increase the temperature of the system, reduce the activation energy required for the electrochemical reaction, and thus further promote the improvement of the electrochemical reaction efficiency.

[0014] 4. The laser-electrochemical composite machining device of the present invention places the metal workpiece to be machined vertically. At the same time, through a clever mechanical structure design, the electrolyte only flows rapidly upward through a narrow slit between the two electrodes, which can effectively avoid the fluctuation of the machining efficiency caused by too high solution concentration in a local area during the electrochemical reaction process. At the same time, assisted by ultrasonic vibration, it can accelerate the movement of the bubbles generated during the machining process and promote the flow of the solution, avoiding the scattering of the incident laser by the bubbles attached to the material surface during the machining process.

[0015] 5. The laser-electrochemical composite machining device of the present invention can realize the composite machining of two modes according to the machining requirements, which is not available in the traditional tube electrode composite machining. At the initial stage of machining, in order to require high machining efficiency and sacrifice part of the machining quality, a machining method mainly based on laser and assisted by electrochemistry is adopted. At this time, the laser energy density is high and the current density is relatively low. The electrochemical reaction can effectively remove the slag and remelted layer generated during the laser machining process, and the heat conduction effect of the electrolyte is also beneficial to reducing the thermal effect of the laser machining. At the later stage of machining, in order to further improve the machining surface quality, a machining method mainly based on electrochemistry and assisted by laser is adopted. At this time, it is necessary to reduce the laser energy density and increase the current density. The laser can quickly remove the passivation film generated during the electrochemical machining process and improve the machining efficiency. Description of the Drawings

[0016] Figure 1 is a schematic structural diagram of the laser-electrochemical composite machining device of the present invention;

[0017] Figure 2 is an assembly drawing of the nozzle and the base;

[0018] Figure 3 is an assembly drawing of the base and the reaction vessel;

[0019] Figure 4 is a structural diagram of the transparent electrode. Detailed Embodiments

[0020] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0021] As Figures 1-4 shown, the present invention provides a laser-electrochemical composite machining device, including an optical unit, an electrochemical reaction unit, and a fluid control unit.

[0022] The optical unit includes a nanosecond green laser 1, an XY two-axis laser scanning galvanometer 2, a focusing lens 3, and a control system 20.

[0023] Among them, the wavelength of the nanosecond green laser is 500 - 560 nm, the output power is 10 - 80 W, the pulse width is 1 - 15 ns, and the frequency is 30 kHz - 500 Hz. The processing software built in the control system 20 controls the emission of the nanosecond green laser 1, and the laser beam is output after being focused by the XY two-axis laser scanning galvanometer 2 and the focusing lens 3.

[0024] The electrochemical reaction unit includes a copper sheet 4, a cathode 5, a metal anode workpiece 6, a reaction vessel 7, an electrolyte 8, a wire 9, a DC power supply 10, a base 18, and a liquid storage tank 19.

[0025] Both the reaction vessel 7 and the liquid storage tank 19 are transparent acrylic containers, which can transmit high-energy laser beams, and the light transmittance is greater than 90%. The reaction vessel 7 is vertically and fixedly placed above the base 18, and both the reaction vessel 7 and the base 18 are arranged in the liquid storage tank 19. There are two grooves opened at the bottom of the reaction vessel 7, and a slit is arranged between the two grooves, and the width of the slit is about 1 - 3 mm. The cathode 5 and the metal anode workpiece 6 are both vertically placed and fixedly clamped in the two grooves, and they are respectively connected to the negative and positive electrodes of the DC power supply 10 through the wire 9. The DC power supply 10 is used to provide electrons for the electrochemical reaction to proceed.

[0026] The side wall of the liquid storage tank 19 is provided with a liquid inlet and a liquid outlet, the bottom of the base 18 is provided with a liquid inlet, there is a cavity inside, and the top is provided with an opening.

[0027] The cathode 5 is made of transparent ITO (indium tin oxide) conductive glass. The ITO conductive glass is composed of a substrate glass 21 and an ITO thin film 22. The thickness of the ITO thin film 22 is 190 - 650 nm, the light transmittance is greater than 80%, the resistance is 2 - 8 Ω, and the copper sheet 4 is adhered to the ITO thin film 22 to enhance the conductivity stability. The electrolyte 8 can adopt a neutral salt solution and is not suitable for using a strong acid solution. On the one hand, the strong acid will etch the ITO thin film, resulting in the failure of the conductivity of the ITO glass. On the other hand, it is easy to cause environmental pollution.

[0028] After the laser beam output by the nanosecond green laser 1 passes through the XY two-axis laser scanning galvanometer 2 and the focusing lens 3, it passes through the transparent liquid storage tank 19, the reaction vessel 7, and the cathode 5, and then is focused on the surface of the metal anode workpiece 6.

[0029] The fluid control unit includes a pipeline 11, a check valve 12, a filter 13, a micro pump 14, a main container 15, an ultrasonic vibration platform 16, and a nozzle 17.

[0030] The main container 15 is used to hold the electrolyte 8. The liquid inlet end of the micro pump 14 is communicated with the main container 15. After being filtered by the filter 13, the liquid outlet end of the micro pump 14 passes through the liquid inlet of the liquid storage tank 19 and the liquid inlet of the base 18, and is injected into the nozzle 17 arranged in the internal cavity of the base 18.

[0031] The nozzle 17 is installed in the internal cavity of the base 18. The outlet of the nozzle 17 is communicated with the bottom slit of the reaction vessel 7. Thus, the electrolyte 8 can be sprayed into the bottom slit of the reaction vessel 7, so that the electrolyte 8 can flow rapidly in the narrow slit between the cathode 5 and the metal anode workpiece 6, thereby ensuring the rapid update of the electrolyte between the two electrodes and reducing the influence of concentration polarization.

[0032] The electrolyte in the liquid storage tank 19 flows back into the main container 15 through its liquid outlet and the pipeline 11. A check valve 12 for preventing the solution from flowing back is arranged on the pipeline 11.

[0033] The ultrasonic vibration platform 16 is installed at the bottom of the liquid storage tank 19 and is used to remove the bubbles, reaction products and impurities generated by the electrochemical reaction through ultrasonic vibration.

[0034] The specific steps for metal processing using the above device are as follows:

[0035] (1) The cathode 5 and the metal anode workpiece 6 to be processed are respectively vertically and fixedly placed in two grooves of the transparent acrylic reaction vessel 7 filled with the electrolyte; the anode and the cathode are respectively connected to the positive and negative electrodes of the DC power supply 10.

[0036] (2) Adjust the position of the laser focus, input the laser processing parameters into the processing software built in the control system 20, control the nanosecond green laser 1 to emit light through the software, and control the laser scanning galvanometer 2 to perform scanning motion to mark the surface of the sample. At the same time, turn on the ultrasonic vibration platform 16, the micro pump 14 and the DC power supply 10. The ultrasonic vibration makes the bubbles generated during the processing and the electrochemically dissolved impurities float up rapidly, avoiding their adverse effects on the conduction of the laser beam and the electrochemical reaction. The micro pump 14 realizes the circulating flow of the electrolyte 8, ensuring the rapid update of the electrolyte 8. The DC power supply 10 provides electrons to promote the electrochemical reaction, and melts the melt generated during the laser processing of the surface of the metal anode workpiece 6. Through the combined laser and electrochemical processing, the high-precision marking processing of the metal anode workpiece 6 is finally realized.

[0037] It is obvious to those skilled in the art that the present invention can be changed in various ways, and such changes are not considered to deviate from the scope of the present invention. All such modifications obvious to those skilled in the art will be included within the scope of the present claims.

Claims

1. A laser and electrochemical composite machining device, comprising an optical unit, an electrochemical reaction unit, and a fluid control unit; characterized in that, The optical unit includes a nanosecond green laser (1), an XY two-axis laser scanning galvanometer (2), a focusing lens (3), and a control system (20); the electrochemical reaction unit includes a copper sheet (4), a cathode (5), a metal anode workpiece (6), a reaction vessel (7), an electrolyte (8), a wire (9), a DC power supply (10), a base (18), and a liquid storage tank (19); both the reaction vessel (7) and the liquid storage tank (19) are transparent acrylic containers with a light transmittance greater than 90%; the reaction vessel (7) is vertically and fixedly placed above the base (18), and both the reaction vessel (7) and the base (18) are arranged in the liquid storage tank (19); two grooves are opened at the bottom of the reaction vessel (7), and a slit is arranged between the two grooves; the cathode (5) and the metal anode workpiece (6) are both vertically placed in the two grooves and fixedly clamped, and the two are respectively connected to the negative and positive electrodes of the DC power supply (10) through the wire (9); the electrolyte (8) is sprayed into the space between the cathode (5) and the metal anode workpiece (6) through the slit, and the cathode (5) is a transparent indium tin oxide conductive glass; the laser beam output by the nanosecond green laser (1) passes through the XY two-axis laser scanning galvanometer (2) and the focusing lens (3), and then passes through the transparent liquid storage tank (19), reaction vessel (7), and cathode (5), and is focused on the surface of the metal anode workpiece (6). The fluid control unit includes a pipeline (11), a check valve (12), a filter (13), a micro pump (14), a main container (15), and a nozzle (17); the main container (15) is used to hold the electrolyte (8), the inlet end of the micro pump (14) is communicated with the main container (15), and the outlet end of the micro pump (14) is filtered by the filter (13) and then passes through the inlet of the liquid storage tank (19) and the inlet of the base (18) and is injected into the nozzle (17) arranged in the internal cavity of the base (18); the nozzle (17) is installed in the internal cavity of the base (18), and the outlet of the nozzle (17) is communicated with the slit at the bottom of the reaction vessel (7) for spraying the electrolyte (8) into the slit at the bottom of the reaction vessel (7); the electrolyte in the liquid storage tank (19) flows back into the main container (15) through its outlet and the pipeline (11), and a check valve (12) for preventing the solution from flowing back is arranged on the pipeline (11).

2. The laser and electrochemical composite machining device according to claim 1, wherein, The fluid control unit further includes an ultrasonic vibration platform (16), and the ultrasonic vibration platform (16) is installed at the bottom of the liquid storage tank (19) for removing the bubbles, reaction products, and impurities generated by the electrochemical reaction through ultrasonic vibration.

3. The laser and electrochemical composite machining device according to claim 1, wherein The indium tin oxide conductive glass is composed of a substrate glass (21) and an ITO thin film (22), the thickness of the ITO thin film (22) is 190 - 650 nm, and the light transmittance is greater than 80%.

4. The laser and electrochemical composite machining device according to claim 3, characterized in that, A copper sheet (4) is also adhered to the ITO thin film (22) to enhance the stability of conductivity.

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