Passive electrolytic etching device and method

Abstract

This invention discloses a passive electrolytic etching apparatus and method, relating to the field of electrolytic machining technology. It includes an electrolytic cell, at least one electrode assembly, and an insulating component. All electrode assemblies are arranged along a first direction, and each electrode assembly includes an anode electrode and a cathode electrode. An insulating component is provided between the anode and cathode electrodes to ensure electrical insulation between them. The electrolytic cell is used to hold an electrolyte, and the surface of the workpiece to be electrolyzed is immersed in the electrolyte. Both the anode and cathode electrodes of the electrode assembly are positioned opposite the surface to be processed, with the ends of the anode electrode and cathode electrode closest to the surface being placed in the electrolyte. The anode and cathode electrodes of each electrode assembly are connected to the positive and negative terminals of a power source, respectively, so that current flows sequentially through the anode electrode, the electrolyte, the material to be removed on the surface to be processed, the electrolyte, and the cathode electrode, removing the material. This invention provides energy-saving and environmentally friendly production processes, reduces processing costs, and ensures processing quality.

Description

Technical Field

[0001] This invention relates to the field of electrochemical processing technology, and in particular to a passive electrochemical etching apparatus and method. Background Technology

[0002] With the development of the electronic information industry, circuit boards, which serve as carriers for electronic communication equipment and automotive components, are also constantly being updated and replaced. In order to meet the needs of circuit and signal transmission, their circuit design is becoming increasingly complex and sophisticated, which puts forward higher requirements for the manufacturing process of circuit boards.

[0003] Traditional circuit boards are mainly processed using chemical etching. However, this process has the following drawbacks: the chemical etching solutions required are usually highly toxic, and the effective components in the solution are continuously consumed as the etching process progresses, resulting in high economic costs; a large amount of waste liquid is generated during the chemical etching process, and the waste liquid post-treatment process is complex and costly, which is not in line with the development trend of green manufacturing.

[0004] Electrolytic machining is a special processing method based on anodic electrochemical dissolution. It boasts advantages such as high processing efficiency, no tool wear, recyclable electrolyte, no limitations imposed by material mechanical properties, and suitability for large-area forming, making it widely used in the processing and manufacturing of metal materials. Addressing the environmental problems and high economic costs of traditional chemical etching processes, research has attempted to introduce electrolytic machining into the circuit board manufacturing field. For example, Chinese patent CN110636710A proposes a method for simultaneous electrolytic etching and electroplating of fine circuit lines on printed circuit boards. This technology uses low-toxicity or non-toxic electrolytes (such as sodium chloride or sodium nitrate solutions) for electrolytic etching, and the electrolyte is recyclable, meeting the development requirements of green manufacturing and satisfying the processing needs of fine circuit board manufacturing.

[0005] Currently, electrolytic etching of circuit boards requires connecting the cathode and anode electrodes to the positive and negative terminals of a power supply, with the circuit board connected to the positive terminal to process the entire large circuit board. However, the circuit layout on circuit boards is usually extremely complex, and a circuit break may occur on the electrode plate. Once a break occurs, that area cannot be processed, resulting in an "island" phenomenon. Furthermore, during electrolytic etching, because the corrosion rate across different areas of the circuit board surface is difficult to maintain consistently, when copper material in the peripheral areas is preferentially removed, the remaining copper material in the central area may experience an electrical break with the conductive parts, preventing electrolytic removal of the central area and creating another "island" phenomenon. Additionally, when applying electrolytic etching, because the circuit board needs to be connected to the positive terminal of a power supply, and the geometric dimensions of the conductive parts are much smaller than the entire area to be processed, current concentration occurs at the conductive parts, leading to burn-in defects. These problems severely limit the application of electrolytic etching technology in circuit board manufacturing. Therefore, there is an urgent need to develop a new passive electrolytic etching device and method to meet the current manufacturing demands for high-precision, high-complexity circuit boards. Summary of the Invention

[0006] The purpose of this invention is to provide a passive electrolytic etching apparatus and method to solve the problems existing in the prior art. The production process is energy-saving and environmentally friendly, meets the requirements of green environmental protection, reduces processing costs, and ensures processing quality.

[0007] To achieve the above objectives, the present invention provides the following solution: This invention provides a passive electrolytic etching apparatus, comprising an electrolytic cell, at least one electrode assembly, and at least one insulating component. All the electrode assemblies are arranged along a first direction, and each electrode assembly includes an anode electrode and a cathode electrode. The insulating component is disposed between each anode electrode and the cathode electrode, and each insulating component is used to electrically insulate the corresponding anode electrode and cathode electrode. The electrolytic cell is used to hold an electrolyte, and the surface of the workpiece to be electrolyzed is immersed in the electrolyte. The anode electrode and the cathode electrode of each electrode assembly are arranged opposite to the surface to be processed, and the ends of each anode electrode and the cathode electrode near the surface to be processed are placed in the electrolyte.

[0008] Preferably, all the cathode electrodes and all the anode electrodes are arranged alternately, and an insulating component is provided between any adjacent cathode electrodes and anode electrodes.

[0009] Preferably, it further includes a clamping device capable of clamping or releasing the electrode assembly and the insulating component.

[0010] Preferably, the clamping device includes a telescopic bracket and a clamping body. The clamping body is connected to the telescopic bracket. The clamping body can clamp or release the electrode assembly and the insulating component. The telescopic bracket can drive the clamping body to move closer to or further away from the workpiece to be electrolyzed.

[0011] Preferably, it further includes a transmission device disposed within the electrolytic cell, the transmission device being used to transport the workpiece to be electrolyzed and to move the workpiece to be electrolyzed along the first direction.

[0012] Preferably, the transmission device includes a transmission drive device, a conveyor belt, and two transmission rollers. The conveyor belt is wound around the two transmission rollers, and both the conveyor belt and each of the transmission rollers are disposed inside the electrolytic cell. The transmission drive device is connected to the transmission rollers and is capable of driving the transmission rollers to rotate around their own axes.

[0013] Preferably, the system further includes an electrolyte circulation system, which includes a main pump and a filter device. The main pump and the filter device are disposed between the inlet and outlet of the electrolytic cell. The main pump enables the electrolyte to circulate between the electrolytic cell, the main pump, and the filter device, and the filter device is used to filter the electrolyte.

[0014] The present invention also provides a passive electrolytic etching method for the passive electrolytic etching apparatus described above, comprising the following steps: S1. Place the workpiece to be electrolyzed in the electrolyte of the electrolytic cell, such that the end of each anode electrode near the surface to be processed and the end of each cathode electrode near the surface to be processed are placed in the electrolyte and are positioned opposite to the surface to be processed. S2. Connect the anode electrode and the cathode electrode of each electrode assembly to the positive and negative terminals of the power supply, respectively, so that the current flows sequentially through each anode electrode, the electrolyte, the material to be removed on the surface to be processed, the electrolyte and the corresponding cathode electrode, and removes the material to be removed, thereby realizing the electrolytic etching of the workpiece to be electrolyzed.

[0015] Preferably, it further includes a clamping device, which includes a telescopic bracket and a clamping body. The clamping body is connected to the telescopic bracket. The clamping body can clamp or release the electrode assembly and the insulating component. The telescopic bracket can drive the clamping body to move closer to or further away from the workpiece to be electrolyzed. S1 further includes: clamping the electrode assembly and the insulating component onto the clamping body, moving the clamping body toward the workpiece to be electrolyzed via the telescopic bracket, and adjusting the distance between the electrode assembly and the surface to be processed to a set distance.

[0016] Preferably, it further includes a transmission device, which is disposed inside the electrolytic cell and is used to transport the workpiece to be electrolyzed and move the workpiece to be electrolyzed along the first direction; S2 further includes: after the anode electrode and the cathode electrode are respectively connected to the positive and negative terminals of the power supply, the transmission device drives the workpiece to be electrolyzed to move along the first direction, so as to perform electrolytic etching on multiple positions of the workpiece to be electrolyzed.

[0017] The present invention achieves the following technical effects compared to the prior art: This invention provides a passive electrolytic etching apparatus and method, comprising an electrolytic cell, at least one electrode assembly, and at least one insulating component. All electrode assemblies are arranged along a first direction, and each electrode assembly includes an anode electrode and a cathode electrode. An insulating component is provided between each anode electrode and a cathode electrode, and each insulating component is used to electrically insulate the corresponding anode electrode and cathode electrode. The electrolytic cell is used to hold an electrolyte, and the surface of the workpiece to be electrolyzed is immersed in the electrolyte. The anode electrode and cathode electrode of each electrode assembly are arranged opposite to the surface to be processed, and the ends of each anode electrode and each cathode electrode near the surface to be processed are placed in the electrolyte.

[0018] When the anode and cathode electrodes are connected to the positive and negative terminals of the power supply, respectively, the power supply, the anode electrode, the electrolyte directly below the anode electrode, the material to be removed from the workpiece (such as excess copper film on the circuit board to be processed), the electrolyte directly below the cathode electrode, and the cathode electrode can form a closed circuit. Current flows from the anode electrode through the electrolyte directly below it, the excess copper film on the circuit board to be processed, and the electrolyte directly below the cathode electrode, finally flowing into the cathode electrode. Because the current flows from the anode electrode through the electrolyte into the excess copper film on the circuit board to be processed, under the influence of the electric field, the material directly below the anode electrode... Excess copper film is induced with a negative charge. When current flows from the copper film directly below the cathode electrode to the cathode electrode, under the influence of the electric field, the copper film directly below the cathode electrode loses electrons and is induced with a positive charge, creating a potential difference in the excess copper film on the circuit board to be processed. Therefore, a voltage exists, the value of which is between the voltage of the cathode electrode and the voltage of the anode electrode. Since the current flows from the copper film directly below the cathode electrode to the cathode electrode, the copper film at that point is equivalent to the positive electrode. Under the influence of the current, electrochemical dissolution occurs (oxidation forms metal cations that dissolve into the electrolyte), and the excess copper film is removed. This embodiment uses the field-induced principle to remove excess copper elements and other metal materials from the surface of the workpiece without direct connection to the power supply, achieving passive electrolytic processing and enabling island-free processing. The circuit board does not need to be electrically connected, avoiding electrical burns to the material, and achieving high-efficiency and high-quality processing of the circuit board circuit. Compared with traditional chemical etching, the production process is energy-saving and environmentally friendly, meeting green environmental protection requirements and reducing processing costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the passive electrolytic etching apparatus provided in Example 1; Figure 2 Schematic diagram of the working principle of the passive electrolytic etching device provided in Example 1 Figure 1 ; Figure 3 Schematic diagram of the working principle of the passive electrolytic etching device provided in Example 1 Figure 2 ; Figure 4 This is a schematic diagram of the processing procedure of the passive electrolytic etching apparatus provided in Example 1; Figure 5 A flowchart of the passive electrolytic etching method provided in Example 2; In the diagram: 100. Passive electrolytic etching device; 1. Electrolytic cell; 2. Anode electrode; 3. Cathode electrode; 4. Insulating component; 5. Workpiece to be electrolyzed; 6. Telescopic support; 7. Clamping body; 8. Transmission device; 9. Transmission drive device; 10. Main pump; 11. Filter device; 12. Electrolyte temperature control system; 13. Support plate; 14. Electrolyte; 15. Anti-corrosion dry film; 16. Copper film; 17. Circuit board insulating body; 18. Conveyor belt. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that in the description of this invention, the terms "upper," "lower," "left," "right," "inner," "outer," "front," "rear," "center," "longitudinal," "transverse," "length," "width," "thickness," "vertical," "horizontal," "top," "bottom," "clockwise," and "counterclockwise," etc., indicating directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. These are merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Additionally, it should be noted that in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] The purpose of this invention is to provide a passive electrolytic etching apparatus and method to solve the problems existing in the prior art. The production process is energy-saving and environmentally friendly, meets the requirements of green environmental protection, reduces processing costs, and ensures processing quality.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1 like Figures 1-4 As shown, this embodiment provides a passive electrolytic etching apparatus 100, including an electrolytic cell 1, at least one electrode assembly, and at least one insulating component 4. All electrode assemblies are arranged along a first direction, and each electrode assembly includes an anode electrode 2 and a cathode electrode 3. An insulating component 4 is provided between each anode electrode 2 and cathode electrode 3, and each insulating component 4 is used to electrically insulate the corresponding anode electrode 2 and cathode electrode 3. The electrolytic cell 1 is used to hold an electrolyte 14, and the surface to be processed of the workpiece 5 to be electrolyzed is immersed in the electrolyte 14. The anode electrode 2 and cathode electrode 3 of each electrode assembly are arranged opposite to the surface to be processed, and the end of each anode electrode 2 near the surface to be processed and the end of each cathode electrode 3 near the surface to be processed are placed in the electrolyte 14.

[0026] When the anode electrode 2 and cathode electrode 3 are connected to the positive and negative terminals of the power supply, respectively, the power supply, anode electrode 2, electrolyte 14 directly below the anode electrode 2, the material to be removed from the workpiece 5 (such as excess copper film 16 on the circuit board to be processed), electrolyte 14 directly below the cathode electrode 3, and the cathode electrode 3 can form a closed circuit. Current flows from the anode electrode 2 through the electrolyte 14 directly below the anode electrode 2, the excess copper film 16 on the circuit board to be processed, and the electrolyte 14 directly below the cathode electrode 3, finally flowing into the cathode electrode 3. Because the current flows from the anode electrode 2 through the electrolyte 14 into the excess copper film 16 on the circuit board to be processed, under the influence of the electric field, the anode electrode 2... The excess copper film 16 below is induced with a negative charge; when the current flows from the copper film 16 directly below the cathode electrode 3 to the cathode electrode 3, under the action of the electric field, the copper film 16 directly below the cathode electrode 3 loses electrons and is induced with a positive charge, so that there is a potential difference in the excess copper film 16 on the circuit board to be processed, and therefore there is a voltage. The voltage value is between the voltage of the cathode electrode 3 and the voltage of the anode electrode 2. When the current flows from the copper film 16 directly below the cathode electrode 3 to the cathode electrode 3, it is equivalent to the copper film 16 at this point being the positive electrode. Under the action of the current, electrochemical dissolution occurs (it is oxidized to form metal cations that dissolve into the electrolyte 14), and the excess copper film 16 is removed. This embodiment employs the field-induced principle to remove excess copper and other metallic materials from the surface of the workpiece 5 without direct connection to a power source, achieving passive electrolytic machining. This avoids the phenomenon of localized areas being unprocessable due to circuit breakage or inconsistent corrosion rates across different areas of the circuit board surface, enabling island-free machining. The circuit board requires no lead-in current, avoiding material burns and achieving high-efficiency and high-quality machining of the circuit board. Compared to traditional chemical etching, the production process is energy-saving and environmentally friendly, meeting green environmental protection requirements and reducing processing costs.

[0027] In some specific embodiments, all cathode electrodes 3 and all anode electrodes 2 are arranged alternately, and an insulating component 4 is provided between any adjacent cathode electrodes 3 and anode electrodes 2. This causes the electrodes of all electrode assemblies to be in an alternating positive and negative charged state. Therefore, not only can the cathode electrodes 3 and anode electrodes 2 of each electrode assembly form a current with the electrolyte 14 and the material to be removed, but also the cathode electrodes 3 (or anode electrodes 2) of each electrode assembly and the anode electrodes 2 (or cathode electrodes 3) of adjacent electrode assemblies can form a current with the electrolyte 14 and the material to be removed, which is beneficial to improving processing efficiency.

[0028] In some embodiments, a clamping device is also included, which can clamp or release the electrode assembly and the insulating component 4. The clamping device has clamping and releasing functions, which facilitates the assembly and disassembly of the electrode assembly and the insulating component 4.

[0029] In some specific embodiments, the clamping device includes a telescopic bracket 6 and a clamping body 7. The clamping body 7 is connected to the telescopic bracket 6 and can clamp or release the electrode assembly and the insulating component 4. The telescopic bracket 6 can drive the clamping body 7 to move closer to or further away from the workpiece 5 to be electrolyzed. The distance between the lower end of the electrode assembly and the surface to be processed can be adjusted by adjusting the telescopic bracket 6, thereby adjusting the processing gap.

[0030] In some specific implementations, the machining gap is generally 0.1mm-1mm. If the gap is too small, it may cause a short circuit between the cathode and anode, burning the workpiece. If the gap is too large, it will cause the machining current to be excessively dispersed, resulting in poor machining effect.

[0031] In some specific embodiments, a transmission device 8 is also included. The transmission device 8 is disposed in the electrolytic cell 1 and is used to transport the workpiece 5 to be electrolyzed and move the workpiece 5 to be electrolyzed along a first direction.

[0032] In some specific embodiments, the transmission device 8 includes a transmission drive device 9, a conveyor belt 18, and two transmission rollers. The conveyor belt 18 is wound around the two transmission rollers, and both the conveyor belt 18 and each transmission roller are disposed inside the electrolytic cell 1. The transmission drive device 9 is connected to the transmission rollers and can drive the transmission rollers to rotate around their own axis. The workpiece 5 to be electrolyzed is placed on the conveyor belt 18, and the workpiece 5 to be electrolyzed is moved along a first direction by the conveyor belt 18.

[0033] It should be noted that since the electrolyte 14 is mostly a corrosive solution, the transmission device 8 needs to be sealed to isolate it from the electrolyte 14, or it needs to be treated with anti-corrosion measures, such as using 316 stainless steel to extend its service life.

[0034] In some specific embodiments, the transmission drive device 9 includes two motors, the output ends of which are fixedly connected to two transmission rollers respectively.

[0035] In some specific embodiments, a support plate 13 is fixedly connected inside the electrolytic cell 1, and the two ends of each transmission roller are rotatably connected to the two support plates 13 respectively.

[0036] In some specific embodiments, an electrolyte 14 circulation system is also included. The electrolyte 14 circulation system includes a main pump 10 and a filter device 11. The main pump 10 and the filter device 11 are arranged between the inlet and outlet of the electrolytic cell 1. The main pump 10 enables the electrolyte 14 to circulate between the electrolytic cell 1, the main pump 10 and the filter device 11. The filter device 11 is used to filter the electrolyte 14.

[0037] In some specific embodiments, an electrolyte temperature control system 12 is also included. The electrolyte temperature control system 12 includes an electrolyte 14 temperature regulating device and a temperature detection device (such as a temperature sensor). The temperature detection device is used to monitor the temperature of the electrolyte 14. The temperature detection device is connected to the electrolyte 14 temperature regulating device, which is used to regulate the temperature of the electrolyte 14 so that the temperature of the electrolyte 14 is maintained at a specified processing temperature.

[0038] In some specific embodiments, the clamping body 7 includes a first fixing plate, a second fixing plate, a third fixing plate, and fastening bolts. One end of the first fixing plate and one end of the second fixing plate are respectively fixedly connected to both ends of the third fixing plate. The fastening bolts are threadedly connected to the first fixing plate and can pass through the first fixing plate. The fastening bolts can clamp the electrode assembly and the insulating component 4 onto the second fixing plate. The clamping body 7 of this embodiment can clamp electrode assemblies and insulating components 4 of different thicknesses, making it flexible in application.

[0039] In some specific embodiments, the electrolytic cell 1 is fixed on the ground, and the electrolyte 14 temperature regulating device and temperature detection device are fixed on the electrolytic cell 1. One end of the main pump 10 is connected to the outlet of the electrolytic cell 1, and the other end is connected to the inlet of the filter device 11. The outlet of the filter device 11 is connected to the inlet of the electrolytic cell 1.

[0040] In some specific embodiments, the workpiece 5 to be electrolyzed is an electronic device such as a circuit board, electronic circuit substrate, or thin-film circuit. It should be noted that this embodiment is not limited to processing electronic devices; it can achieve electrolytic removal of any conductive metal material.

[0041] Example 2 like Figure 5 As shown, this embodiment provides a passive electrolytic etching method based on the passive electrolytic etching apparatus 100 in Embodiment 1, including the following steps: S1. Place the workpiece 5 to be electrolyzed in the electrolyte 14 of the electrolytic cell 1, so that the end of each anode electrode 2 near the surface to be processed and the end of each cathode electrode 3 near the surface to be processed are placed in the electrolyte 14 and are positioned opposite to the surface to be processed. S2. Connect the anode electrode 2 and cathode electrode 3 of each electrode assembly to the positive and negative terminals of the power supply, respectively, so that the current flows sequentially through each anode electrode 2, electrolyte 14, the object to be removed on the surface to be processed, electrolyte 14 and the corresponding cathode electrode 3, and removes the object to be removed, thereby realizing the electrolytic etching of the workpiece 5 to be electrolyzed.

[0042] In some specific embodiments, a clamping device is also included. The clamping device includes a telescopic bracket 6 and a clamping body 7. The clamping body 7 is connected to the telescopic bracket 6. The clamping body 7 can clamp or release the electrode assembly and the insulating component 4. The telescopic bracket 6 can drive the clamping body 7 to move closer to or further away from the workpiece 5 to be electrolyzed. S1 also includes: clamping the electrode assembly and insulating component 4 onto the clamping body 7, moving the clamping body 7 toward the workpiece 5 to be electrolyzed via the telescopic bracket 6, and adjusting the distance between the electrode assembly and the surface to be processed to a set distance.

[0043] In some specific embodiments, a transmission device 8 is also included. The transmission device 8 is disposed in the electrolytic cell 1 and is used to transport the workpiece 5 to be electrolyzed and move the workpiece 5 to be electrolyzed along a first direction. S2 further includes: after the anode electrode 2 and the cathode electrode 3 are connected to the positive and negative terminals of the power supply respectively, the transmission device 8 drives the workpiece 5 to be electrolyzed to move along the first direction so as to perform electrolytic etching on multiple positions of the workpiece 5 to be electrolyzed.

[0044] In some specific embodiments, the passive electrolytic etching method of this embodiment specifically includes: Step 1: Based on the required circuit board, design the number of electrode components to form a multi-module spliced ​​electrode. Both the anode electrode 2 and the cathode electrode 3 are composed of titanium alloy plates (the size of the titanium alloy plates can be adjusted according to the size of the circuit board to be processed). An insulating component 4 of a certain thickness is installed between each titanium alloy plate. At the same time, insulation treatment is also performed on both outer ends of the multi-module spliced ​​electrode. The surface of the titanium alloy plate of the multi-module spliced ​​electrode needs to be plated with an iridium-tantalum alloy coating to prevent the titanium alloy plate, which serves as the anode, from being excessively corroded during electrolysis, thus causing processing failure.

[0045] Step 2: The circuit boards to be processed are sequentially fixed onto the transmission device 8. The transmission device 8 needs to be immersed in the electrolyte 14, therefore it needs to be well-sealed and corrosion-resistant. It should be noted that the circuit boards mentioned here are already processed circuit boards, with a layer of anti-corrosion dry film 15 covering the inner circuitry on the circuit board's insulating body 17; the material to be removed is the copper on the circuit board that is not covered by the anti-corrosion dry film 15. Step 3: Use a clamping device to fix the multi-module assembled electrode. The clamping body 7 is bolted to the telescopic bracket 6. The telescopic bracket 6 has a vertical telescopic function. Adjust the position of the telescopic bracket 6 so that the multi-module assembled electrode is placed directly above the circuit board to be processed. The telescopic bracket 6 drives the multi-module assembled electrode to move vertically. Adjust the processing gap. Generally, the processing gap is 0.1-1mm. Step 4: Connect the power supply to the multi-module splicing electrodes, so that the multi-module splicing electrodes are alternately charged with positive and negative charges. For example, there are 10 splicing electrodes, named electrode 1, 2, 3...10. That is, splicing electrodes 1, 3, 5, 7, and 9 are connected to the negative terminal of the power supply, and splicing electrodes 2, 4, 6, 8, and 10 are connected to the positive terminal of the power supply. When the anode electrode 2 and the cathode electrode 3 are connected to the positive and negative terminals of the power supply respectively, the power supply, anode electrode 2, electrolyte 14 directly below anode electrode 2, the material to be removed on the workpiece 5 (such as excess copper film 16 on the circuit board to be processed), electrolyte 14 directly below cathode electrode 3, and cathode electrode 3 can form a closed circuit. The current flows from anode electrode 2 through electrolyte 14 directly below anode electrode 2, excess copper film 16 on the circuit board to be processed, electrolyte 14 directly below cathode electrode 3, and finally flows into cathode electrode 3. Since the current flows from anode electrode 2 through electrolyte 14 into the circuit board to be processed... Under the influence of an electric field, the excess copper film 16 directly below the anode electrode 2 is induced with a negative charge. When current flows from the copper film 16 directly below the cathode electrode 3 to the cathode electrode 3, under the influence of an electric field, the copper film 16 directly below the cathode electrode 3 loses electrons and is induced with a positive charge, creating a potential difference on the excess copper film 16 on the circuit board to be processed, thus creating a voltage. This voltage value is between the voltage of the cathode electrode 3 and the voltage of the anode electrode 2. Since the current flows from the copper film 16 directly below the cathode electrode 3 to the cathode electrode 3, the copper film 16 at this location is equivalent to being the positive electrode. Under the influence of the current, electrochemical dissolution occurs (the copper film 16 is oxidized to form metal cations that dissolve into the electrolyte 14), and the excess copper film 16 is removed. It should be noted that although the copper film 16 covered by the anti-corrosion dry film 15 also has current flowing through it, this copper film 16 only acts as a conductor and does not come into contact with the electrolyte 14, so it will not be electrolytically corroded. Start the electrolyte temperature control system 12 to adjust the electrolyte 14 to the specified processing temperature, and monitor the temperature of the electrolyte 14 in real time during the processing to ensure that the electrolyte 14 can be kept constant at the specified processing temperature; Start the electrolyte 14 circulation system. The main pump 10 pumps the processed and contaminated electrolyte 14 into the filter device 11. The clean electrolyte 14 after filtration returns to the electrolytic cell 1. This cycle is repeated to ensure that the electrolyte 14 used in the processing is clear and clean. During processing, the power supply is first turned on. Once the power supply reaches the specified processing voltage, the transmission device 8 is activated. The transmission device 8 sequentially feeds the circuit board to be processed under the multi-module splicing electrodes. As the transmission device 8 continuously feeds, excess copper on the circuit board is eventually removed, achieving automated continuous processing and improving production efficiency. Step 5: After all the circuit boards to be processed are completed, turn off the transmission device 8, then turn off the power, adjust the telescopic bracket 6, and adjust the multi-module splicing electrode above the electrolyte 14. After processing is completed, the electrolyte 14 circulation system continues to operate until the electrolyte 14 becomes clear, at which point the electrolyte 14 circulation system can be shut down.

[0046] The schematic diagram of the passive electrolytic etching apparatus 100 and method proposed in this invention is shown below. Figure 3 As shown: After the processing circuit is turned on, the voltage of the anode electrode 2 is U0. Current flows from the electrolyte 14 into the copper film 16 directly below the anode. Under the action of the induced current, the copper film 16 directly below the anode electrode 2 is induced with a negative charge. The current flows from the copper film 16 directly below the anode electrode 2 to the copper film 16 directly below the cathode electrode 3, and then from the copper film 16 directly below the cathode electrode 3 to the cathode electrode 3. Under the action of the induced current, the copper film 16 directly below the cathode electrode 3 is induced with a positive charge. The copper film 16 directly below the anode electrode 2 is negatively charged, and the copper film 16 directly below the cathode electrode 3 is positively charged. Therefore, there is a potential difference in the copper film 16, that is, there is a voltage U1 in the copper film 16 (U2 < U1 < U0). There is a potential difference between the copper film 16 directly below the cathode electrode 3 and the cathode electrode 3. The copper film 16 directly below the cathode electrode 3 is equivalent to the anode. Under the action of the current, the anode (the copper film 16 directly below the cathode electrode 3) undergoes electrochemical corrosion in the electrolyte 14 and is thus removed.

[0047] The processing steps of the passive electrolytic etching apparatus 100 and method proposed in this invention are as follows: Figure 4 As shown, where, Figure 4 (a) is a schematic diagram of the pre-processing equipment and circuit board. Figure 4 (b) is a schematic diagram of the device and circuit board during the processing. Figure 4 (c) is a schematic diagram of the processed device and circuit board.

[0048] Furthermore, in traditional electrolytic etching, both the cathode electrode 3 and the anode electrode 2 must be connected to the positive and negative terminals of a power supply. For electrolytic etching of circuit boards, the circuit board, acting as the anode, is connected to the positive terminal of the power supply via a wire, which can cause burns during processing. This invention proposes a passive electrolytic etching device 100 and method for passive circuit boards. By combining multiple sets of sheet electrodes into a single unit, with each electrode sheet insulated from the others and adjacent electrode sheets connected to opposite electrodes, current flows from the anode electrode 2, through the electrolyte 14, into the circuit board to be processed, and then exits from the surface of the circuit board opposite the cathode electrode 3, flowing back into the cathode electrode 3 through the electrolyte 14. During current outflow, the copper on the circuit board surface loses electrons, is oxidized to form metal cations, and dissolves into the electrolyte 14, thereby removing the material. This invention avoids the drawback of burns caused by directly connecting the circuit board to the positive terminal of the power supply. During processing, the copper film 16 with the anti-corrosion dry film 15 on top only acts as a conductor and will not be dissolved. However, the copper film 16 without the anti-corrosion dry film 15 on top undergoes electrochemical dissolution and is removed under the action of current. The multi-module splicing electrode is fixed in place, and the transmission device 8 sequentially transports the circuit board to be processed to the bottom of the multi-module splicing electrode, thus realizing the processing of the entire circuit board.

[0049] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A passive electrolytic etching apparatus, characterized in that: The device includes an electrolytic cell, at least one electrode assembly, and at least one insulating component. All the electrode assemblies are arranged along a first direction, and each electrode assembly includes an anode electrode and a cathode electrode. The insulating component is disposed between each anode electrode and the cathode electrode, and the insulating component is used to electrically insulate the corresponding anode electrode and cathode electrode. The electrolytic cell is used to hold an electrolyte, and the surface of the workpiece to be electrolyzed is immersed in the electrolyte. The anode electrode and the cathode electrode of each electrode assembly are disposed opposite to the surface to be processed, and the end of each anode electrode near the surface to be processed and the end of each cathode electrode near the surface to be processed are placed in the electrolyte.

2. The passive electrolytic etching apparatus according to claim 1, characterized in that: All the cathode electrodes and all the anode electrodes are arranged alternately, and an insulating component is provided between any adjacent cathode electrodes and anode electrodes.

3. The passive electrolytic etching apparatus according to claim 1, characterized in that: It also includes a clamping device capable of clamping or releasing the electrode assembly and the insulating component.

4. The passive electrolytic etching apparatus according to claim 3, characterized in that: The clamping device includes a telescopic bracket and a clamping body. The clamping body is connected to the telescopic bracket. The clamping body can clamp or release the electrode assembly and the insulating component. The telescopic bracket can drive the clamping body to move closer to or further away from the workpiece to be electrolyzed.

5. The passive electrolytic etching apparatus according to claim 1, characterized in that: It also includes a transmission device disposed inside the electrolytic cell, the transmission device being used to transport the workpiece to be electrolyzed and to move the workpiece to be electrolyzed along the first direction.

6. The passive electrolytic etching apparatus according to claim 5, characterized in that: The transmission device includes a transmission drive device, a conveyor belt, and two transmission rollers. The conveyor belt is wound around the two transmission rollers, and the conveyor belt and each of the transmission rollers are disposed inside the electrolytic cell. The transmission drive device is connected to the transmission rollers and can drive the transmission rollers to rotate around their own axes.

7. The passive electrolytic etching apparatus according to claim 1, characterized in that: It also includes an electrolyte circulation system, which includes a main pump and a filter device. The main pump and the filter device are located between the inlet and outlet of the electrolytic cell. The main pump enables the electrolyte to circulate between the electrolytic cell, the main pump and the filter device, and the filter device is used to filter the electrolyte.

8. A passive electrolytic etching method based on the passive electrolytic etching apparatus according to any one of claims 1 to 7, characterized in that: Includes the following steps: S1. Place the workpiece to be electrolyzed in the electrolyte of the electrolytic cell, such that the end of each anode electrode near the surface to be processed and the end of each cathode electrode near the surface to be processed are placed in the electrolyte and are positioned opposite to the surface to be processed. S2. Connect the anode electrode and the cathode electrode of each electrode assembly to the positive and negative terminals of the power supply, respectively, so that the current flows sequentially through each anode electrode, the electrolyte, the material to be removed on the surface to be processed, the electrolyte and the corresponding cathode electrode, and removes the material to be removed, thereby realizing the electrolytic etching of the workpiece to be electrolyzed.

9. The passive electrolytic etching method according to claim 8, characterized in that: It also includes a clamping device, which includes a telescopic bracket and a clamping body. The clamping body is connected to the telescopic bracket. The clamping body can clamp or release the electrode assembly and the insulating component. The telescopic bracket can drive the clamping body to move closer to or further away from the workpiece to be electrolyzed. S1 further includes: clamping the electrode assembly and the insulating component onto the clamping body, moving the clamping body toward the workpiece to be electrolyzed via the telescopic bracket, and adjusting the distance between the electrode assembly and the surface to be processed to a set distance.

10. The passive electrolytic etching method according to claim 8, characterized in that: It also includes a transmission device, which is disposed inside the electrolytic cell and is used to transport the workpiece to be electrolyzed and move the workpiece to be electrolyzed along the first direction. S2 further includes: after the anode electrode and the cathode electrode are respectively connected to the positive and negative terminals of the power supply, the transmission device drives the workpiece to be electrolyzed to move along the first direction, so as to perform electrolytic etching on multiple positions of the workpiece to be electrolyzed.

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