Electrolytic machining gap detection system and method based on optical fiber sensing

Abstract

The invention discloses an electrochemical machining gap detection system and method based on optical fiber sensing. The detection system comprises an optical fiber sensor, a laser emitting device and a laser detection device. The optical fiber sensor is arranged on the tool electrode, and the detection end of the optical fiber sensor extends to the electrolytic machining gap and directly faces the machining surface of the workpiece; the laser emitting device is connected with the optical fiber sensor so as to be suitable for emitting laser and transmitting the laser to the electrolytic machining gap and the workpiece machining surface through the optical fiber sensor. The laser detection device is connected with the optical fiber sensor so as to be suitable for detecting the electrolyte transmitted by the optical fiber sensor and laser reflected by the workpiece machining surface. Through the optical fiber sensor integrated in the tool electrode, electrolytic machining gap information of a specific machining position can be directly detected and obtained; the optical signal sensitively responds to the change of the machining gap, the real-time performance is high, the detection precision can be improved, the detection process is simplified, and the method can be suitable for a high-speed small-gap electrolytic machining scene.

Description

Technical Field

[0001] This invention relates to the field of electrolytic machining technology, and in particular to a detection system and method for detecting gaps in electrolytic machining based on fiber optic sensing. Background Technology

[0002] Electrolytic machining relies on electrochemical reactions to dissolve the anolyte metal workpiece in ionic form, theoretically achieving micron-level and submicron-level machining precision. Electrolytic machining offers advantages such as being unaffected by material hardness and strength, producing excellent surface integrity, and eliminating tool electrode wear, making it widely used in advanced manufacturing fields such as aerospace, medical devices, and precision molds.

[0003] In electrochemical machining (ECM), the size of the machining gap between the tool electrode (cathode) and the workpiece (anode) is one of the key factors affecting machining accuracy and efficiency. Influenced by factors such as changes in machining temperature, effective ion concentration in the electrolyte, and electrolyte pressure fluctuations, the actual ECM gap dynamically changes with different machining times and positions. If the machining gap is too large, stray currents on the workpiece surface will reduce the localization of the machining process. Simultaneously, the increased impedance of the electrolyte within the gap will cause a decrease in the machining current, leading to reduced machining efficiency. If the machining gap is too small, difficulties in electrolyte renewal and the removal of machining products may lead to electrode short circuits or even arcing, resulting in machining failure. Therefore, online detection and control of the machining gap has always been a key research focus for high-efficiency and high-precision ECM.

[0004] Currently, various online detection methods for electrolytic machining gaps have been developed. Among them, the gap voltage or current detection method identifies the gap size by calculating statistical characteristics such as the average value and variance of voltage or current. This method has a simple structure and controllable cost; however, the average voltage and current signals are not sensitive to changes in the gap size, resulting in low detection accuracy and making it difficult to apply to high-precision electrolytic machining. The machining voltage waveform distortion detection method uses the waveform changes of the gap pulse voltage as the basis for detecting the gap size. However, this characteristic is affected by the electrolyte composition and concentration, and the double-layer characteristics of different workpiece materials vary, requiring frequent adjustments to the detection parameters in practical applications. Furthermore, detection methods relying on indirect signals such as electrolyte conductivity, pH value, and temperature can reflect the average state of the electrolytic machining gap, but still require electrode collision protection in conjunction with electrical signals, and cannot accurately obtain the gap size at critical positions of the tool electrode in real time.

[0005] The above-mentioned detection methods can detect or predict the state of the gap in electrolytic machining to a certain extent, but they are difficult to meet the accuracy and real-time requirements of gap detection when the machining gap is small and the machining speed is fast. Summary of the Invention

[0006] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one objective of this invention is to propose a detection system and method for electrolytic machining gaps based on fiber optic sensing, aiming to solve the problems of insufficient detection accuracy and poor real-time performance in electrolytic machining gaps.

[0007] This invention proposes a detection system for the gap in electrolytic machining based on fiber optic sensing. The detection system includes a fiber optic sensor, a laser emitting device, and a laser detection device. The fiber optic sensor is disposed on the tool electrode, and the detection end of the fiber optic sensor extends to the electrolytic machining gap and faces the workpiece machining surface. The laser emitting device is connected to the fiber optic sensor to emit laser light, which is transmitted through the fiber optic sensor to the electrolytic machining gap and the workpiece machining surface. The laser detection device is connected to the fiber optic sensor to detect the electrolyte transmitted by the fiber optic sensor and the laser light reflected from the workpiece machining surface.

[0008] The electrolytic machining gap detection system of the present invention can directly detect and acquire electrolytic machining gap information at a specific machining position through an optical fiber sensor integrated inside the tool electrode; the feedback optical signal is sensitive to changes in the machining gap and has strong real-time performance, which can improve detection accuracy, simplify the detection process, and is applicable to high-speed, small-gap electrolytic machining scenarios.

[0009] According to some embodiments of the present invention, the fiber optic sensor includes an input multimode fiber and a signal multimode fiber. The input multimode fiber is connected to a laser emitting device to be adapted to transmit an input laser signal; the signal multimode fiber is connected to a laser detection device to be adapted to transmit a feedback optical signal.

[0010] According to some embodiments of the present invention, the input multimode fiber is constructed in multiple ways.

[0011] According to some embodiments of the present invention, the fiber optic sensors are configured as a plurality of spaced-apart sensors.

[0012] According to some embodiments of the present invention, the input multimode fiber and the signal multimode fiber are constructed as a shared multimode fiber or two independent multimode fibers.

[0013] According to some embodiments of the present invention, the multimode optical fiber is made of quartz material or fluorine-doped quartz material or germanium-doped quartz material.

[0014] According to some embodiments of the present invention, the fiber optic sensor further includes a protective layer disposed on the outer periphery of the input multimode fiber and the signal multimode fiber.

[0015] According to some embodiments of the present invention, the detection system further includes a signal amplifier and / or a DC filter unit, wherein the signal amplifier is connected to the laser detection device and the DC filter unit is connected to the laser detection device.

[0016] This invention also proposes a method for detecting gaps in electrolytic machining based on fiber optic sensing. Using the aforementioned fiber optic sensing-based electrolytic machining gap detection system, the detection method includes the following steps: Laser is emitted into the gap of electrolytic machining and the feedback optical signal is collected; Extracting optical signal data based on feedback optical signals; By comparing the optical signal data with the preset calibration data, the size and state of the electrolytic machining gap are determined.

[0017] According to some embodiments of the present invention, in the method for detecting gaps in electrolytic machining based on fiber optic sensing, the optical signal data includes optical power data and optical wavelength data.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of the electrolytic machining gap detection system according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure of the electrolytic machining gap detection system according to Embodiment 2 of the present invention; Figure 3 This is a schematic diagram of the electrolytic machining gap detection system according to Embodiment 3 of the present invention; Figure 4 This is a schematic diagram of the axial structure of a tool electrode for electrolytic machining according to some embodiments of the present invention; Figure 5 This is a schematic diagram of the radial structure of a tool electrode for electrolytic machining according to some embodiments of the present invention; Figure 6 This is a flowchart of a method for detecting electrolytic machining gaps according to some embodiments of the present invention; Figure 7 This is a calibration curve diagram showing the relationship between optical signal power data and processing gap according to some embodiments of the present invention.

[0020] Figure label: Tool electrode 11; Metal cathode 111; Insulating layer 112; Workpiece 12; Machining gap 13; Electrolyte 14; Fiber optic sensor 2; multimode fiber 21; input multimode fiber 211; signal multimode fiber 212; protective layer 22; detection end 23; signal end 24; input laser signal A; feedback optical signal B; 3. Spectral power meter; 4. Signal amplifier; 5. DC filter unit; 6. Dichroic mirror; 7. Reflector; 8. Control unit. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] In the electrochemical machining equipment, the tool electrode 11 is connected to the negative terminal of the machining power supply, and the workpiece 12 is connected to the positive terminal of the machining power supply to realize electrochemical machining. During the machining process, the size and state of the electrochemical machining gap 13 are monitored in real time using the detection system and detection method of this application.

[0023] The following is for reference. Figures 1-5 A fiber optic sensing-based gap detection system for electrolytic machining is described according to an embodiment of the present invention.

[0024] This invention proposes a detection system for electrolytic machining gap based on fiber optic sensing. The detection system includes a fiber optic sensor 2, a laser emitting device, and a laser detection device. The fiber optic sensor 2 is disposed on the tool electrode 11, and the detection end 23 of the fiber optic sensor 2 extends to the electrolytic machining gap 13 and is directly opposite to the machining surface of the workpiece 12. The laser emitting device is connected to the fiber optic sensor 2 to emit laser light, which is transmitted through the fiber optic sensor 2 to the electrolytic machining gap 13 and the machining surface of the workpiece 12. The laser detection device is connected to the fiber optic sensor 2 to detect the electrolyte transmitted by the fiber optic sensor 2 and the laser light reflected from the machining surface of the workpiece 12.

[0025] According to the electrolytic machining gap detection system of the present invention, the fiber optic sensor 2 has a detection end 23 and a signal end 24. The signal end 24 is connected to a laser emitting device and a laser detection device. The detection end 23 extends and is exposed in the electrolytic machining gap 13, and is directly opposite the machining surface of the workpiece 12. The laser emitting device emits a laser, and the input laser signal A is coupled into the fiber optic sensor 2 through the signal end 24. After being transmitted to the detection end 23, it enters the electrolytic machining gap 13 at a certain divergence angle. After being scattered and reflected by the electrolyte 14 and the surface of the workpiece 12, it returns to the fiber optic sensor 2 and is transmitted to the signal end 24. The feedback optical signal B is further transmitted to the laser detection device, which can acquire the optical signal data in the feedback optical signal B. Based on the optical signal data, the size and shape of the electrolytic machining gap 13 can be identified through analysis and processing, realizing real-time monitoring of the electrolytic machining gap 13 in order to control the electrolytic machining process. The size of the electrolytic machining gap 13 refers to the width h of the electrolytic machining gap 13, which can be controlled by controlling the feed speed; the state of the electrolytic machining gap 13 refers to the processing products such as bubbles that may appear in the electrolytic machining gap 13 during the electrolytic machining process. The detection system of the present invention can monitor the generation frequency, morphology, bubble discharge and other characteristics of the processing products in real time.

[0026] According to the electrolytic machining gap detection system of the present invention, the electrolytic machining gap 13 information of a specific machining position can be directly detected and acquired by the fiber optic sensor 2 integrated inside the tool electrode 11; the optical signal transmitted by the fiber optic cable is sensitive to changes in the machining gap 13 and has strong real-time performance, which can improve detection accuracy, simplify the detection process, and is applicable to high-speed, small-gap electrolytic machining scenarios.

[0027] In some embodiments, the fiber optic sensor 2 is embedded in the tool electrode 11 and extends along the feed direction of the tool electrode 11; and the detection end 23 of the fiber optic sensor 2 is flush with the processing end face of the tool electrode 11, so as to directly detect the size of the electrolytic processing gap 13.

[0028] Furthermore, in some embodiments, such as Figure 4 As shown, the tool electrode 11 is constructed as a slender tubular structure, specifically including a metal cathode 111 and an insulating layer 112. The insulating layer 112 covers the outer peripheral sidewall of the metal cathode 111 and is coaxially arranged with the metal cathode 111. The metal cathode 111 is the working component for electrode reaction, and its processing end face is in contact with the electrolyte 14 to realize electrolytic machining of the workpiece 12. The insulating layer 112 can suppress lateral stray corrosion, thereby improving machining accuracy. In addition, a detection channel is formed in the metal cathode 111 of the tool electrode 11. The fiber optic sensor 2 is disposed in the detection channel, and the detection end 23 of the fiber optic sensor 2 is disposed at the opening of the detection channel to be exposed in the electrolytic machining gap 13 and emit laser light into the electrolytic machining gap 13.

[0029] According to some embodiments of the present invention, the fiber optic sensor 2 includes an input multimode fiber 211 and a signal multimode fiber 212. The input multimode fiber 211 is connected to a laser emitting device to transmit an input laser signal A; the signal multimode fiber 212 is connected to a laser detection device to transmit a feedback optical signal B. In this embodiment, the input laser signal A emitted by the laser emitting device is transmitted to the electrolytic machining gap 13 through the input multimode fiber 211. After being scattered and reflected by the electrolyte 14 and the workpiece 12 machining surface, it enters the signal multimode fiber 212 and is transmitted to the laser detection device through the signal multimode fiber 212. This embodiment utilizes the multimode fiber 211 to achieve optical signal transmission, resulting in low loss, improved signal transmission stability, and enhanced detection accuracy. According to some embodiments of the present invention, multiple input multimode optical fibers 211 are constructed. In this embodiment, multiple input multimode optical fibers 211 are provided in one optical fiber sensor 2. By appropriately increasing the number of input multimode optical fibers 211, the irradiation area of ​​the input laser can be increased, and the detection robustness can be improved. Furthermore, based on this embodiment, the power of the input laser can be increased, so that it can participate in the material removal process in addition to serving as a detection light source. Further, the ratio of the number of input multimode optical fibers 211 to signal multimode optical fibers 212 is matched according to the processing requirements, and the area ratio of the metal cathode 111 to the sidewall insulating layer 112 is matched to achieve real-time synchronous detection of the electrolytic processing gap 13 in the laser electrolytic composite processing process.

[0030] According to some embodiments of the present invention, the fiber optic sensors 2 are configured as a plurality of spaced-apart units. In this embodiment, such as Figure 3 As shown, multiple fiber optic sensors 2 are provided to enable multi-position detection of the processing gap 13; in this embodiment, the detection robustness can be further improved by appropriately increasing the number of fiber optic sensors 2.

[0031] Furthermore, to reduce the influence of the fiber optic sensor 2 on the surface morphology of electrolytic machining, the fiber optic sensor 2 can be placed in an area with lower machining accuracy requirements; alternatively, a smaller fiber optic sensor 2 can be selected, and compensation can be made by optimizing process parameters such as electrolyte concentration and voltage.

[0032] According to some embodiments of the present invention, the input multimode fiber 211 and the signal multimode fiber 212 are constructed as a shared multimode fiber 21 or two independent multimode fibers 21. In this embodiment, the fiber optic sensor 2 can be constructed using a single multimode fiber 21, which serves as both the laser input multimode fiber 211 and the feedback signal output multimode fiber 21. The input laser signal A is transmitted from the multimode fiber 21 to the electrolytic machining gap 13, and after scattering and reflection, the feedback light signal B returns to the same multimode fiber 21 and is transmitted to the laser detection device. When a single multimode fiber 21 is used as the fiber optic sensor 2, the fiber optic sensor 2 can be applied to the detection of micro-scale electrolytic machining gaps 13, such as when the tool electrode 11 is smaller than 200 μm. The fiber optic sensor 2 can also be composed of multiple multimode fibers 21, such as two multimode fibers 21, one as the input multimode fiber 211 and the other as the signal multimode fiber 212. The two multimode fibers 21 are arranged closely together. The input laser signal A is transmitted from the input multimode fiber 211 to the electrolytic machining gap 13. After scattering and reflection, the feedback light signal B returns to the signal multimode fiber 212 and is transmitted to the laser detection device. When two multimode fibers 21 are used to form the fiber optic sensor 2, the sensor is mainly used for macroscopic electrolytic machining. This embodiment, by changing the composition of the fiber optic sensor 2, can match electrolytic machining of different scales and achieve accurate detection of the electrolytic machining gap 13.

[0033] According to some embodiments of the present invention, the multimode optical fiber 21 is made of quartz material or fluorine-doped quartz material or germanium-doped quartz material. In this embodiment, the multimode optical fiber 21 is made of quartz material or element-doped adaptive materials (such as fluorine-doped quartz material, germanium-doped quartz material, etc.), which has corrosion resistance and chemical stability and will not reduce the service life of the tool electrode 11; moreover, quartz has good insulation properties, which can perform the sidewall insulation function while realizing the detection of the electrolytic machining gap 13.

[0034] In some embodiments, the core diameter of the multimode fiber 21 ranges from 10 μm to 200 μm.

[0035] According to some embodiments of the present invention, the fiber optic sensor 2 further includes a protective layer 22, which is disposed on the outer periphery of the entire input multimode fiber 211 and signal multimode fiber 212. In this embodiment, the protective layer 22 is disposed on the outer periphery of the multimode fiber 21. The protective layer 22 is made of a corrosion-resistant insulating material, such as Teflon, and can fill the tiny gap between the multimode fiber 21 and the tool electrode 11 to prevent the electrolyte 14 from seeping in.

[0036] Furthermore, such as Figure 5 As shown, the fiber optic sensor 2 has multiple configuration options. Figure 5(a) illustrates the structure of two sets of fiber optic sensors 2 set in the tool electrode 11, with the two sets of fiber optic sensors 2 set at a distance of 180°. Figure 5 Figure (b) illustrates a structure in which four sets of fiber optic sensors 2 are arranged in the tool electrode 11, with the four sets of fiber optic sensors 2 arranged sequentially at 90° intervals; further, Figure 5 Figure (c) illustrates a structure in which four sets of fiber optic sensors 2 are arranged in the tool electrode 11, and each fiber optic sensor 2 is provided with two input multimode fibers 211. By increasing the number of fiber optic sensors 2 or the number of input multimode fibers 211, the detection robustness can be improved.

[0037] According to some embodiments of the present invention, the detection system further includes a signal amplifier 4 and / or a DC filter unit 5, wherein the signal amplifier 4 is connected to the laser detection device, and the DC filter unit 5 is connected to the laser detection device. In this embodiment, by setting the signal amplifier 4, the collected optical signal can be amplified and processed as optical signal data when the intensity of the feedback optical signal B is weak, thereby improving the sensitivity and accuracy of detection; by setting the DC filter unit 5, high-frequency components in the feedback optical signal B can be extracted as the collected feedback optical signal B data, which can suppress interference and improve signal quality and detection accuracy.

[0038] According to some embodiments of the present invention, the laser detection device is configured as an optical power meter or a spectral power meter 3. By setting the optical power meter, optical power data can be collected in the feedback optical signal B, and the change in the width h of the electrolytic machining gap 13 can be identified based on the optical power data. By setting the spectral power meter 3, optical power data and optical wavelength data can be collected in the feedback optical signal B, and the state of processing products such as bubbles in the electrolytic machining gap 13 can be detected based on the combination of optical power data and optical wavelength data.

[0039] According to some embodiments of the present invention, the detection system for the electrolytic machining gap based on fiber optic sensing further includes a control unit 8. The control unit 8 is connected to a laser detection device to analyze and process the optical signal data acquired by the laser detection device to determine the size and state of the electrolytic machining gap 13. Further, the control unit 8 includes a data acquisition module and a data analysis and processing module. The data acquisition module acquires optical signal data, and the data analysis and processing module analyzes and processes the optical signal data. Even further, the control unit 8 is communicatively connected to the electrolytic machining equipment and can control the electrolytic machining process based on the optical signal data, such as adjusting the feed speed of the tool electrode 11. Specifically, during the machining process, after acquiring the optical signal data, the control unit 8 compares it with a set calibration value, and then outputs a control signal to automatically adjust machining parameters such as the feed speed of the tool electrode 11 to achieve closed-loop control of the machining gap 13.

[0040] The electrolytic machining gap detection system based on fiber optic sensing according to the present invention, in conjunction with the above embodiments, has the following specific embodiments: Example 1: As Figure 1 As shown, the fiber optic sensor 2 consists of a single multimode fiber 21. An externally input laser signal A is coupled into the multimode fiber 21 from the signal end 24 of the fiber optic sensor 2 for transmission. The detection end 23 of the fiber optic sensor 2 is flush with the processing end face of the tool electrode 11. After the input laser is emitted from the detection end 23, it passes through the electrolyte 14 within the electrolytic processing gap 13 and irradiates the processing surface of the workpiece 12. Since the contours of the processing surface of the workpiece 12 and the processing end face of the tool electrode 11 are basically similar during electrolytic processing, the output laser, after being reflected from the processing surface, passes through the electrolytic processing gap 13 again and enters the multimode fiber 21, and is transmitted along the fiber to the signal end 24 for emission. The emitted feedback light signal B is received by the laser detection device, i.e., the spectral power meter 3, which further feeds the light signal data back to the control unit 8. When the interface reflected light and the feedback light signal B are difficult to separate effectively, the low transmission loss and stable light transmission characteristics of the multimode fiber 21 are utilized. The high-frequency components of the signal are extracted by the DC filtering unit 5 and used as the feedback light signal B data collected during the processing.

[0041] Example 2: As Figure 2 As shown, the fiber optic sensor 2 consists of two multimode optical fibers 21. An externally input laser signal A is coupled into the input multimode optical fiber 211 of the fiber optic sensor 2. After the input laser is transmitted inside the input multimode optical fiber 211, it exits from the detection end 23 at a certain divergence angle and enters the processing gap 13. Under different processing gap 13 sizes, the proportion of laser light that can be reflected by the workpiece 12 processing surface and re-enter the signal multimode optical fiber 212 is also different. Part of the reflected light that meets the gap conditions and divergence angle range is used as the feedback light signal B, which enters the signal multimode optical fiber 212, is transmitted through it, and is then exited and received by the spectral power meter 3. The spectral power meter 3 feeds back the optical signal data to the control unit 8. When the intensity of the feedback light signal B is weak, the signal amplifier 4 is used to amplify and process the collected optical signal as the feedback light signal B data.

[0042] Example 3: As Figure 3 As shown, the detection system includes at least two fiber optic sensors 2, one of which is composed of a single multimode fiber 21 (see...). Figure 3 (Left side), suitable for detecting the gap 13 in micro-scale electrolytic machining; another fiber optic sensor 2 consists of two multimode optical fibers 21 (see left side). Figure 3(Right side), suitable for detecting larger-scale electrolytic machining gaps 13. During detection, for the left fiber optic sensor 2, the external input laser signal A is partially reflected by the dichroic mirror 6, coupled from the signal end 24 of the fiber optic sensor 2 into the interior of the multimode fiber 21 for transmission, exits through the detection end 23, passes through the electrolyte 14 in the machining gap, and irradiates the machining surface of the workpiece 12; after the output laser is reflected on the machining surface, the feedback light signal B passes through the machining gap 13 and re-enters the multimode fiber 21, and is transmitted along the multimode fiber 21 to the signal end 24 for exit; the exited feedback light signal B is partially transmitted through the dichroic mirror 6 and received by the spectrometer power meter 3 of the detection device. For the right-side fiber optic sensor 2, the external laser is reflected by the reflector 7 and coupled into the input multimode fiber 211 of the sensor. After propagation within the multimode fiber 211, it exits from the fiber end face with a certain divergence angle and enters the processing gap 13. The emitted laser is reflected by the surface of the workpiece 12 and enters the signal multimode fiber 212. After transmission through the signal multimode fiber 212, it exits, and the emitted feedback light signal B is received by the spectral power meter 3. The spectral power meter 3 is connected to the control unit 8 and transmits the optical signal data to the control unit 8 for analysis and processing.

[0043] like Figure 6 As shown, this invention also proposes a method for detecting gaps in electrolytic machining based on fiber optic sensing. The detection method includes the following steps: S1. An optical fiber sensor 2 is installed in the tool electrode 11 of electrolytic machining along its feed direction, thereby constructing the above-mentioned detection system for electrolytic machining gap based on optical fiber sensing. S2. Emit input laser signal A into the electrolytic machining gap 13 and collect feedback optical signal B; S3. Extract optical signal data based on feedback optical signal B; S4. Compare the optical signal data with the preset calibration data to determine the size and state of the electrolytic machining gap 13.

[0044] According to the fiber optic sensing-based electrolytic machining gap 13 detection method of the present invention, the electrolytic machining gap 13 is detected by an fiber optic sensor 2 integrated inside the tool electrode 11. The detection method of the present invention is simple and easy to implement, the feedback signal is sensitive to changes in the machining gap, and it has strong real-time performance, making it suitable for high-speed, small-gap electrolytic machining scenarios.

[0045] In step S1, the constructed detection system includes a control unit 8. In step S2, the control unit 8 acquires the feedback optical signal B and in step S3, it compares the feedback optical signal B with the calibration value of the process database to identify and determine the size and state of the current electrolytic processing gap 13.

[0046] In some embodiments, in step S3, when the interface reflected light and the feedback light signal B are difficult to separate effectively, i.e., when there is an interference signal, the high-frequency components in the light signal are extracted by the DC filter unit 5 as light signal data collected by the control unit 8.

[0047] In some embodiments, in step S3, when the intensity of the feedback optical signal B is weak, the signal amplifier 4 is used to amplify the acquired optical signal, and the amplified optical signal data is used as the optical signal data acquired by the control unit 8.

[0048] According to some embodiments of the present invention, in the method for detecting gaps in electrolytic machining based on fiber optic sensing, the optical signal data includes optical power data and optical wavelength data. In this embodiment, by combining dynamic data detection of optical power and optical wavelength, not only can the presence of machining short circuits be detected, but also the gap size and status at the arrangement position of the fiber optic sensor 2 can be detected; this can further improve detection accuracy and reduce detection errors.

[0049] Furthermore, before electrolytic processing, i.e., between steps S1 and S2, the following steps are also included: establishing calibration data in advance through experiments, and recording the correspondence between the optical signal and the calibration value of the electrolytic processing gap 13 under different processing parameter conditions. In one embodiment, the calibration curve of the relationship between the optical power data in the optical signal and the processing gap is as follows: Figure 7 As shown, under the corresponding processing parameters, when the processing gap gradually decreases from 2500 μm to 420 μm, the power of the feedback optical signal B shows a slow upward trend, reaching a peak of approximately 10.2 μW at 420 μm. With further reduction in the processing gap, the power of the feedback optical signal B decreases rapidly, and the decrease exhibits good linearity and stability. Within this range, when the processing gap is less than 300 μm, the measurement accuracy reaches ±5 μm, enabling high-precision online detection of the processing gap.

[0050] Furthermore, in order to reduce the impact of the fiber optic sensor 2 on the surface morphology of electrolytic machining, the output voltage of the electrolytic machining power supply and the concentration of the electrolyte 14 are adjusted during the electrolytic machining process to maintain a suitable machining gap 13 size, thereby minimizing the impact of the fiber optic sensor 2 on the surface morphology of electrolytic machining.

[0051] This invention also proposes a closed-loop control method for the gap in electrolytic machining based on fiber optic sensing. The closed-loop control method includes the following steps: The size and condition of the electrolytic machining gap 13 were determined using the above-mentioned detection system and method. Adjust the feed rate of the tool electrode 11 according to the size and condition of the electrolytic machining gap 13.

[0052] The control unit 8 adjusts the feed rate of the tool electrode 11 in real time based on the identification results to regulate and maintain the size of the electrolytic machining gap 13. Specifically, the control unit 8 compares the optical signal data with the calibration values ​​in the process database in real time. If the electrolytic machining gap 13 is detected to be too large, the feed rate of the tool electrode 11 is increased to improve the electrolytic machining efficiency. If the electrolytic machining gap 13 is detected to be too small or there is a problem with product discharge in the machining gap, the feed rate of the tool electrode 11 is reduced to avoid short circuits. Furthermore, during the electrolytic machining process, the control unit 8 synchronously controls the acquisition of optical signals and the operation of the electrolytic machining equipment, analyzes the optical signal data in real time, and automatically adjusts the feed rate of the tool electrode 11 to achieve closed-loop control of the electrolytic machining gap 13.

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to 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.

[0054] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0055] In the description of this invention, "a plurality of" means two or more.

[0056] In the description of this invention, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0057] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0058] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0059] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A system for detecting the gap of electrochemical machining based on optical fiber sensing, characterized in that, The application relates to an electrolytic machining gap detection system based on optical fiber sensing. The system comprises: an optical fiber sensor arranged on a tool electrode, a detection end of the optical fiber sensor extending to an electrolytic machining gap and facing a workpiece machining surface; a laser emitting device and a laser detecting device, the laser emitting device being connected with the optical fiber sensor and adapted to emit laser and transmit the laser to the electrolytic machining gap and the workpiece machining surface through the optical fiber sensor, the laser detecting device being connected with the optical fiber sensor and adapted to detect electrolyte transmitted by the optical fiber sensor and laser reflected by the workpiece machining surface. The optical fiber sensor comprises: an input multimode optical fiber connected with the laser emitting device and adapted to transmit an input laser signal; and a signal multimode optical fiber connected with the laser detecting device and adapted to transmit a feedback optical signal.

2. The fiber-optic sensing based detection system for electrolytic machining gap according to claim 1, wherein, The input multimode optical fiber is configured as a plurality of input multimode optical fibers. The optical fiber sensor is configured as a plurality of optical fiber sensors arranged at intervals. The input multimode optical fiber and the signal multimode optical fiber are configured as one common multimode optical fiber or two independent multimode optical fibers.

3. The fiber-optic sensing based detection system for electrolytic machining gap according to claim 2, wherein, The multimode optical fiber is made of quartz material or fluorine-doped quartz material or germanium-doped quartz material.

4. The fiber-optic sensing based detection system for electrolytic machining gap according to claim 2, wherein, The optical fiber sensor further comprises: a protective layer arranged on the outer periphery of the input multimode optical fiber and the signal multimode optical fiber.

5. The fiber optic sensor based detection system for electrolytic gap of claim 2, wherein, The system further comprises: a signal amplifier connected with the laser detecting device; and / or a direct current filter unit connected with the laser detecting device.

6. The fiber-optic sensing based detection system for electrolytic machining gap according to claim 5, wherein, The application also discloses an electrolytic machining gap detection method based on optical fiber sensing.

7. The fiber optic sensor based detection system for electrolytic gap of claim 2, wherein, The method comprises the following steps: emitting laser to the electrolytic machining gap and collecting a feedback optical signal; extracting optical signal data based on the feedback optical signal; and comparing the optical signal data with preset calibration data to determine the size and state of the electrolytic machining gap. The optical signal data comprises optical power data and optical wavelength data.

8. The fiber optic sensor based detection system for electrolytic gap of claim 1, wherein, ​ ​ ​ ​ 9. A method for detecting an electrolytic machining gap based on optical fiber sensing, characterized in that, ​ ​ ​ ​ 10. The method of claim 9, wherein the method further comprises: ​

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