Block electrode self-adjusting electrolytic machining device and method based on machine vision control

Abstract

The invention discloses a machine vision control blocking electrode self-adjusting electrolytic machining device and method, and relates to the field of electrolytic machining, and the electrolytic machining is divided into pre-forming electrolytic machining and blocking compensation electrolytic machining. The pre-forming electrolytic machining stage is an electrolytic machining stage in which an integral forming tool cathode is used as a cathode to carry out constant feeding speed on a workpiece, and the pre-forming electrolytic machining stage is used for preliminarily copying and forming the workpiece so as to start the block compensation electrolytic machining stage; in the blocking compensation electrolytic machining stage, a machining area is partitioned, image information of workpiece and blocking electrode electrolytic machining is captured through machine vision, and actual machining gaps of the blocking areas are obtained after the blocking areas are analyzed and processed. And after comparison and calculation are carried out on the target values, an instruction is sent to a motion execution system to control a specified partitioned electrode to carry out compensation electrolytic machining, so that machining errors caused by on-way conductivity fluctuation are eliminated, and finally electrolytic replication forming machining with higher machining precision is achieved in the ultra-long process of the distorted workpiece.

Description

Technical Field

[0001] The present invention relates to the field of electrolytic machining in the field of special machining technology, and in particular to a block electrode self-adjusting electrolytic machining device and method controlled by machine vision. Background Art

[0002] In modern manufacturing, from mold manufacturing to aerospace precision parts manufacturing, ultra-long and twisted workpieces are indispensable. For example, aircraft engine blades have a slender structure, thin and twisted surfaces, and are mostly made of difficult-to-cut materials such as high-temperature alloys. Traditional mechanical processing cannot meet the processing requirements, while electrolytic processing is widely used in the processing and manufacturing of ultra-long and twisted workpieces because of its tool cathode loss-free, good processing surface quality, and no residual stress.

[0003] However, when processing ultra-long twisted workpieces, electrolytic machining also has some problems to be solved. Due to the long processing area, the length of the electrolyte flow will also be correspondingly longer to cover the entire processing area. As the length of the electrolyte flow increases, the electrolyte will be subject to more resistance and pressure loss during the flow process, resulting in a decrease in flow rate, especially in the distal part of the flow channel, where the flow rate may be significantly reduced. During the electrolytic machining process, bubbles, insoluble products and heat will be generated due to electrochemical reactions, and these bubbles, insoluble products and heat will gradually accumulate toward the outlet as the electrolyte flows. On the other hand, the lengthening of the flow channel will also cause large changes in the concentration of the electrolyte at the inlet and outlet during the flow process. These factors will cause large fluctuations in the conductivity of the electrolyte along the process, which will seriously affect the electrolytic replication forming accuracy of the workpiece.

[0004] In order to solve the impact of conductivity fluctuations on machining accuracy, researchers have conducted a lot of exploration. Among them, Wang Hao and others from Anhui University of Technology proposed a programmable energized surface electrolytic machining method and device (Wang Hao, Huang Guohui, Rao Sixian, Zhang Peng, Guo Xiangqin; A programmable energized surface electrolytic machining method and device [P]; Anhui Province: CN202211305079.X, 2022.10.24), setting two sets of assembly tool cathodes on both sides of the anode workpiece, and programming control to energize each assembled cathode block according to the interval set by the program, effectively adjusting the product, bubble, and heat distribution, and can also preferentially remove large excess materials to achieve fast and uniform machining, and ultimately improve the electrolytic machining accuracy and stability of complex surfaces and large-sized workpieces. However, different processing materials require different processing environments and process parameters, which requires a lot of process optimization and simulation in the early stage. In addition, when processing twisted workpieces with ultra-long processes, the impact of the fluctuation of conductivity along the ultra-long process on the machining accuracy of the workpiece is still a key problem that needs to be solved. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a self-adjusting electrolytic processing device and method of block electrodes controlled by machine vision. The present invention performs block processing on the cathode of a forming tool, that is, the tool cathode is divided into a plurality of block electrodes according to different processing areas, and the contacting sides of adjacent block electrodes are insulated and lubricated, so that the cathode can be used as the cathode of the overall forming tool to perform pre-forming electrolytic processing on the workpiece, and each block electrode can be used as a basic processing unit to perform compensatory electrolytic processing on the workpiece respectively, so as to eliminate the processing error caused by the fluctuation of conductivity along the process, and finally achieve electrolytic replication forming processing with higher processing accuracy in the ultra-long process of twisted workpieces;

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] A machine vision controlled self-adjusting electrolytic processing device for block electrodes, comprising a machine vision system, a motion execution system, a fixed adjustment system, an electrolyte circulation system and a real-time monitoring system;

[0008] The machine vision system includes a CCD high-speed camera, a computer and a motion control unit; the CCD high-speed camera captures real-time images of the processing area, the computer analyzes and processes the captured images to calculate the actual processing gap between the workpiece and the cathode, the computer compares and calculates the processing gap and the target value according to the logical relationship of the set program, and then sends a control instruction to the motion control unit, the motion control unit sends a motion instruction to the motion execution system, and the motion execution system drives the cathode to work; the electrolyte circulation system is used to provide electrolyte; the real-time monitoring system is used to monitor the current, electrolyte pressure and temperature parameters in real time, and when the parameters are abnormal, the information is transmitted to the computer and a control instruction to interrupt the feed motion and turn off the pulse power switch is issued; the fixed adjustment system adjusts the workpiece and the cathode to the processing position and fixes them.

[0009] In this scheme, the whole electrolytic machining process is divided into a preforming electrolytic machining stage and a block compensation electrolytic machining stage; the preforming electrolytic machining stage is an electrolytic machining stage in which the cathode of the integral forming tool acts as a cathode and makes a constant feed speed to the workpiece. The function of this stage is to initially replicate the workpiece and then start the block compensation electrolytic machining stage; the block compensation electrolytic machining stage is to partition the machining area, capture the image information of the workpiece and the block electrode electrolytic machining through machine vision, analyze and process the block area, and obtain the actual machining gap of each block area. After comparison and calculation with the corresponding target value, the motion execution system issues instructions to control the specified block electrode to perform block compensation electrolytic machining;

[0010] The machine vision system includes a CCD high-speed camera, a computer and a motion control unit; the CCD high-speed camera is arranged directly above the electrolytic machining area, captures images of the entire machining area of ​​the workpiece and the cathode, and transmits the captured images to the image processing unit of the computer;

[0011] In the above scheme, the computer receives the image transmitted by the CCD high-speed camera, and the image processing unit of the computer respectively performs grayscale conversion, median filter preprocessing, threshold segmentation conversion into a binary image, morphological filter opening operation and Canny edge detection processing on the image. The final transformation result of the image is that the boundaries of the two electrodes are set to white, and the other areas are set to black. The transformed image is scanned line by line to obtain the pixel width of the scanned line, and the pixel width is converted into the actual processing gap according to the corresponding ratio; the computer compares and calculates the actual processing gap obtained by the image processing unit and the corresponding target value according to the logical relationship of the set program, and then sends a control instruction to the motion control unit; the motion control unit receives the instruction issued by the computer, controls the specified motor to drive the motion execution system to perform the corresponding electrolytic processing movement;

[0012] The motion execution system includes an x-axis moving unit, a moving platform, a fixed platform, a dual-axis moving unit, a grabbing robot and a pulse power supply; the motor in the x-axis moving unit receives the motion command issued by the motion control unit, and drives the moving platform to perform a feeding motion in the x-axis direction at a constant speed; the moving platform is installed on the fixed platform, and follows the x-axis moving unit to perform a feeding motion in the x-axis direction at a constant speed, that is, drives the cathode of the integral forming tool to perform a pre-forming electrolytic machining motion, especially, the x-axis constant speed feeding motion of the moving platform continues in the block compensation electrolytic machining stage; the fixed platform is arranged at the bottom of the entire motion execution system, and is equipped with an x-axis moving unit; the transverse and longitudinal motors in the dual-axis moving unit receive the motion command issued by the motion control unit, and move the grabbing robot to a specified position; the grabbing robot includes a mechanical arm and a mechanical gripper, wherein the two inner sides of the mechanical gripper are provided with position sensors to accurately grasp the grabbing slider and perform block compensation electrolytic machining motion; the positive pole of the pulse power supply is connected to the workpiece, and the negative pole is connected to the block electrode to provide energy for electrolytic machining;

[0013] The fixed adjustment system includes an electrolytic cell, an adjustment frame, a fixed guide rail and a grabbing slider; the electrolytic cell is provided with a transparent glass cover plate above the workpiece and the cathode electrolytic processing area, which not only plays a sealing role, but also provides a field of view for the CCD high-speed camera to capture images; the adjustment frame adjusts the workpiece to the initial processing position and plays a role in fixing the workpiece; the grabbing slider is connected above the fixed guide rail, which not only guides the block compensation movement of the block electrode, but also connects the block electrodes tightly together, so that all the block electrodes can accurately form the cathode of the integral forming tool during the initial processing; the grabbing slider is installed on the corresponding fixed guide rail, the grabbing slider is fixedly connected to the block electrode thereon, and position sensors are arranged on both sides of each grabbing slider to ensure that the grabbing robot can accurately grab it;

[0014] The electrolyte circulation system includes an electrolyte tank, a temperature control unit, a liquid inlet pipe, a one-way valve, a liquid inlet filter, a pressure gauge, a hydraulic pump, a liquid outlet pipe, a liquid outlet filter and a waste liquid tank; the electrolyte circulation system provides a high-voltage electrolyte with a constant temperature for the entire electrolytic machining device, ensures that the electrolytic products of the workpiece in the machining area and the cathode gap are discharged smoothly, and recovers the waste liquid after electrolytic machining;

[0015] The real-time monitoring system includes a data acquisition card, a current sensor, a pressure sensor and a temperature sensor; the current sensor, the pressure sensor and the temperature sensor monitor the current, electrolyte pressure and temperature parameters of the entire electrolytic machining process in real time. When any parameter is abnormal, the detection signal is transmitted back to the data acquisition card, and the data is transmitted to the computer, and the computer issues a control instruction to interrupt the feed motion and turn off the pulse power switch to avoid damage to the device caused by a short circuit between the workpiece and the cathode.

[0016] The self-adjusting electrolytic machining device and method of block electrodes controlled by machine vision include the following steps:

[0017] Step S1: The adjustment frame installs the workpiece into the electrolytic cell, adjusts the workpiece to the initial processing position and fixes it; installs the block electrodes on the corresponding fixed guide rails, so that all the block electrodes accurately form the cathode of the integral forming tool, adjusts the motion platform, ensures that the cathode of the integral forming tool is at the initial processing position, and makes the minimum gap between the cathode of the integral forming tool and the workpiece a balanced processing gap;

[0018] Step S2: storing the workpiece balance machining gap, the error threshold of the pre-forming electrochemical machining stage, the error threshold of the block compensation electrochemical machining stage, and the coordinates of the ideal machining contour line of the workpiece in the computer; focusing the CCD high-speed camera on the boundary between the workpiece and the tool cathode, performing light control processing on the entire electrochemical machining area, ensuring correct exposure, reducing noise, and finally capturing high-quality images;

[0019] Step S3: Pre-forming electrolytic machining stage: turn on the pulse power supply and the electrolyte circulation system, start machining, and the computer sends instructions to the motion control unit to control the motor of the x-axis moving unit to drive the motion platform and the cathode of the integral forming tool to perform feeding machining motion at a constant speed in the x-axis direction; at the same time, during the entire machining process, the machine vision system captures, processes and scans the image information of the machining area line by line in real time, calculates the actual machining gap of all scanning lines of the workpiece and the cathode of the integral forming tool, and then makes a difference with the balance machining gap respectively, compares the difference of the scanned lines with the error threshold of the pre-forming electrolytic machining stage, and uses this as the criterion for the end of the pre-forming electrolytic machining stage; if the difference of all scanning lines is less than the error threshold of the pre-forming electrolytic machining stage, the pre-forming electrolytic machining stage ends;

[0020] Step S4: Block compensation electrochemical machining stage: the x-axis constant speed feed machining movement of the preforming electrochemical machining stage continues; the end moment of the preforming electrochemical machining stage is the start moment of the first round of machining in the block compensation electrochemical machining stage; the compensation electrochemical machining of the block electrodes is divided into different rounds for block adjustment, and in each round of compensation electrochemical machining, each block electrode has a basis for forward feeding or backward retreat in that round, that is, the target value of that round of compensation electrochemical machining. The target value of the first round of compensation electrochemical machining is to balance the machining gap, and the target value of each subsequent round of compensation electrochemical machining is the actual machining gap of each block area calculated after the first image capture in the previous round of compensation electrochemical machining; in each round of compensation electrochemical machining, each block electrode is adjusted only once, according to the absolute value of the difference between the block electrode and the corresponding target value of that round. The sizes are adjusted one by one; specifically, at the beginning of each round of compensatory electrolytic machining, the image is first captured and processed, and after the actual machining contour line of the workpiece at the machining moment is extracted, the difference between the data points corresponding to the theoretical contour line stored in the computer in advance is calculated, and if the difference between all data points is within the error threshold preset in the block compensatory electrolytic machining stage, the block compensatory electrolytic machining stage ends, otherwise the actual machining gap of each block area at this moment is calculated, and the difference between the actual machining gap of each block area and the target value is calculated, and the block electrode corresponding to the difference with the largest absolute value is selected to adjust; the method for calculating the actual machining gap of each block electrode is to select four scanning lines that divide the block area into five small areas of equal width, calculate the actual machining gaps corresponding to the four scanning lines and take the average value, and the calculated average value is the actual machining gap between the block electrode and the workpiece. The principle of adjustment of each block electrode is: if the actual machining gap of the block electrode is smaller than the target value of the block electrode in this round of compensatory electrolytic machining, the block electrode is fed forward by the distance of the difference between the target value and the actual machining gap; if the actual machining gap of the block electrode is larger than the target value of the block electrode in this round of compensatory electrolytic machining, the block electrode is retracted by the distance of the difference between the target value and the actual machining gap; when a block electrode is adjusted, it will no longer participate in the sorting of the size of the difference between the actual machining gap and the target value after image capture processing in the next block adjustment of this round.

[0021] Step S5: turning off the pulse power supply, the electrolyte circulation system and the machine vision system, removing the workpiece, and completing the processing of the self-adjusting electrolytic replication of the block electrodes controlled by the machine vision;

[0022] The beneficial effects are:

[0023] 1. The present invention performs block processing on the cathode of the forming tool with an extreme concept, that is, the cathode of the forming tool is divided into several block electrodes according to different processing areas, and the contact sides of adjacent block electrodes are insulated and lubricated, so that the cathode can be used as the cathode of the overall forming tool to perform electrolytic processing movement to the workpiece, and each block electrode can be used as a basic processing unit to perform electrolytic processing movement to the workpiece respectively; machine vision is introduced on the basis of cathode block processing, and the image information of the processing area is captured by a CCD high-speed camera, and the data is transmitted to the image processing unit in the computer. After analysis and processing, the actual processing gap between the workpiece and the cathode is calculated, and then compared with the corresponding target value according to the logical relationship of the set program. After calculation, instructions are issued to the motion execution system, and the overall forming tool cathode and the block electrodes are controlled to perform corresponding electrolytic processing movements in different processing stages.

[0024] 2. The electrolytic machining of the present invention is divided into two machining stages: pre-forming electrolytic machining and block compensation electrolytic machining; the pre-forming electrolytic machining stage is an electrolytic machining stage in which the cathode of the integral forming tool acts as the cathode and makes a constant feed speed to the workpiece. The function of this stage is to preliminarily replicate the workpiece and then start the block compensation electrolytic machining stage; the block compensation electrolytic machining stage is to partition the machining area, capture the image information of the workpiece and the block electrode electrolytic machining through machine vision, analyze and process the block area to obtain the actual machining gap of each block area, compare and calculate with the corresponding target value, and then send instructions to the motion execution system to control the specified block electrode to perform compensation electrolytic machining to eliminate the machining error caused by the conductivity fluctuation along the process, and finally achieve electrolytic replication forming machining with higher machining accuracy in the ultra-long process of twisted workpieces.

[0025] 3. The method of self-adjusting electrolytic machining of block tool electrodes controlled by machine vision in the present invention is suitable for large distorted workpieces with ultra-long processes. The preliminary contour of the workpiece is first replicated through pre-forming electrolytic machining, and then the replication machining error caused by the fluctuation of the conductivity along the ultra-long process is corrected through block compensating electrolytic machining, thereby greatly improving the replication forming accuracy of electrolytic machining of large distorted workpieces.

[0026] 4. In view of the problem that it is difficult to grasp the comprehensive influence of complex multi-physical fields such as processing gap, electric field, flow field, etc. on electrolytic machining, machine vision, as a completely active, non-contact and easy to integrate information measurement and judgment method, combined with the electrolytic machining of the formed cathode limit blocking concept of the present invention, can achieve or even exceed the replication accuracy achieved through a large number of early simulations and process parameter optimization.

[0027] 5. In order to solve the problem of difficulty in designing, processing and correcting the tool cathode when electrolyzing complex workpieces, the block electrode of the present invention divides the overall formed tool cathode into several small block electrodes, which greatly reduces the difficulty and cost of designing, processing and correcting the tool cathode.

[0028] 6. In order to solve the problem that the processing area is too large and a higher current is required when electrolyzing large and complex workpieces, the block electrode of the present invention divides the cathode of the overall forming tool into several small block electrodes, thereby reducing the performance requirements of a single block electrode on the power supply and saving the cost of power supply equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The overall structure diagram of the self-adjusting electrolytic machining device for block electrodes controlled by machine vision;

[0030] Figure 2 It is a schematic diagram of the pre-forming electrolytic machining stage;

[0031] Figure 3 It is a schematic diagram of the block compensation electrochemical machining stage;

[0032] Figure 4 A schematic diagram of the logic flow of computer instructions for the pre-forming electrochemical machining stage;

[0033] Figure 5 A schematic diagram of the logic flow of computer instructions for the block compensation electrochemical machining stage;

[0034] Figure 6 Schematic diagram of a block electrode collected by CCD during the block compensation electrochemical machining stage.

[0035] The reference numerals are as follows:

[0036] 1-CCD high-speed camera; 2-adjustment frame; 3-workpiece; 4-electrolyzer; 5-fixed platform; 6-moving platform; 7-fixed guide rail; 8-grabbing slider; 9-block electrode; 10-tool cathode; 11-liquid outlet pipeline; 12-liquid outlet filter; 13-waste liquid tank; 14-electrolyte tank; 15-liquid inlet pipeline; 16-hydraulic pump; 17-temperature control unit; 18-liquid inlet filter; 19-pressure gauge; 20-check valve; 21-temperature sensor; 22-pressure sensor; 23-data acquisition card; 24-computer; 25-motion control unit; 26-current sensor; 27-pulse power supply; 28-longitudinal motor; 29-longitudinal guide rail; 30-longitudinal lead screw; 31-longitudinal bearing seat; 32-transverse bearing seat; 33-transverse lead screw; 34-mechanical claw; 35-mechanical arm; 36-transverse slider; 37-transverse motor; 38-transverse guide rail; 39-lead screw; 40-guide rail; 41-motor. DETAILED DESCRIPTION

[0037] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] The present invention performs block processing on the cathode of the forming tool in an extreme way, that is, the cathode of the forming tool is divided into a plurality of block electrodes 9 according to different processing areas, and the contacting sides of adjacent block electrodes 9 are insulated and lubricated, so that the cathode can be used as the cathode of the whole forming tool to perform electrolytic processing movement to the workpiece, and each block electrode 9 can be used as a basic processing unit to perform electrolytic processing movement to the workpiece respectively; on the basis of the cathode block processing, machine vision is introduced, and the image information of the processing area is captured by a CCD high-speed camera 1, and the data is transmitted to the image processing unit in the computer 24. After analysis and processing, the actual processing gap between the workpiece and the cathode is calculated, and then compared with the corresponding target value according to the logical relationship of the set program, and the backward movement is executed. The system issues instructions to control the cathode of the integral forming tool and the block electrode to perform preforming electrolytic machining and block compensation electrolytic machining at different machining stages; wherein, the principle of the present invention for detecting the machining gap between the workpiece and the cathode is to find the grayscale jump position of the image grayscale matrix, specifically, the image is grayed, preprocessed by median filtering, converted into a binary image by threshold segmentation, opened by morphological filter and processed by Canny edge detection, the final transformation result of the image is to form a smooth boundary between the anode and the cathode, the boundary of the two electrodes is set to white, and the other areas are set to black, the pixel width of different scanning lines is obtained after scanning the transformed image line by line, and the actual machining gap of different scanning lines is calculated by corresponding ratio;

[0041] A machine vision controlled self-adjusting electrolytic processing device for block electrodes, comprising a machine vision system, a motion execution system, a fixed adjustment system, an electrolyte circulation system and a real-time monitoring system;

[0042] The machine vision system captures, analyzes and processes images of the workpiece and cathode in the processing area to obtain the actual processing gap between the workpiece and the cathode at different processing times, and then compares and calculates with the corresponding target value according to the logical relationship of the set program, and then issues instructions to the motion execution system to control the integral forming tool cathode 10 and the block electrode 9 to perform corresponding electrolytic processing movements in the pre-forming electrolytic processing stage and the block compensation electrolytic processing stage;

[0043] Specifically, the machine vision system includes a CCD high-speed camera 1, a computer 24 and a motion control unit 25; the CCD high-speed camera 1 is arranged directly above the electrolytic machining area, captures images of the entire machining area of ​​the workpiece and the cathode, and transmits the captured images to the image processing unit of the computer 24; the computer 24 analyzes and processes the images transmitted by the CCD high-speed camera 1 to calculate the actual machining gap; the computer 24 compares and calculates the actual machining gap obtained by the image processing unit and the corresponding target value according to the logical relationship of the set program, and then issues a control instruction to the motion control unit 25; the computer 24 is connected to the data acquisition card 23, receives abnormal information of the current, electrolyte pressure and temperature parameters transmitted by the data acquisition card 23, and issues instructions to interrupt the feed motion and the switch of the pulse power supply 27; the motion control unit 25 receives the instructions issued by the computer 24, controls the specified motor to drive the cathode to perform the corresponding electrolytic machining motion;

[0044] Specifically, in the pre-forming electrolytic machining stage, the computer 24 sends instructions to the motion control unit 25 to control the motor 41 of the x-axis moving unit, driving the motion platform 6 and the tool cathode 10 to perform feeding machining motion in the x-axis direction at a constant speed; in the entire pre-forming electrolytic machining stage, the machine vision captures, analyzes and processes the image in real time, and then scans the actual machining gap between the workpiece 3 and the tool cathode 10 line by line, and makes a difference with the balanced machining gap, and compares the difference with a preset error threshold. If the difference is less than the error threshold, the computer 24 issues an instruction to stop the pre-forming electrolytic machining; the machining state reference of the pre-forming electrolytic machining stage Figure 2 As shown, Figure 2 The left side shows the initial processing moment, and the right side shows a moment during the processing;

[0045] Specifically, in the block compensation electrolytic machining stage, the x-axis constant speed feeding machining motion of the motion platform 6 in the preforming electrolytic machining stage continues, and at the same time, the actual machining gap of each block machining area is calculated by scanning line by line, and after comparing and calculating with the corresponding round target value according to the logical relationship of the set program, an instruction is sent to the motion control unit 25 to control the corresponding block electrode 9 to perform compensation electrolytic machining motion, and the machining errors caused by different conductivity in different machining areas are compensated for by electrolytic machining;

[0046] The end time of the pre-forming electrolytic machining stage is the start time of the first round of machining in the block compensation electrolytic machining stage; the compensation electrolytic machining of the block electrode 9 is carried out in different rounds for block adjustment. In each round of compensation electrolytic machining, each block electrode 9 has a basis for forward feeding or backward retreat in this round, that is, the target value of this round of compensation electrolytic machining. The target value of the first round of compensation electrolytic machining is the balanced machining gap, and the target value of each subsequent round of compensation electrolytic machining is the actual machining gap of each block area calculated after the first image capture in the previous round of compensation electrolytic machining; in each round of compensation electrolytic machining, each block electrode 9 is adjusted only once, and is adjusted one by one in the order of the absolute value of the difference between the block electrode 9 and the corresponding target value of this round;

[0047] Specifically, at the beginning of each round of compensatory electrolytic machining, the image is first captured and processed, and after the actual machining contour line of the workpiece at the machining moment is extracted, the difference between the data points corresponding to the theoretical contour line pre-stored in the computer 24 is calculated. If the difference between all data points is within the preset error threshold, the block compensatory electrolytic machining stage is ended. Otherwise, the actual machining gap of each block area at that moment is calculated, and the difference between the actual machining gap of each block area and the target value is calculated, and the block electrode 9 corresponding to the difference with the largest absolute value is selected for adjustment; the method for calculating the actual machining gap of the block electrode 9 is to select four scanning lines that divide the block area into five small areas of equal width, calculate the actual machining gaps corresponding to the four scanning lines and take the average value, and the calculated average value is the actual machining gap between the block electrode 9 and the workpiece 3.

[0048] Specifically, the principle of adjusting each block electrode 9 is: if the actual machining gap of the block electrode 9 is smaller than the target value of the block electrode 9 in this round of compensation electrolytic machining, the block electrode 9 is fed forward by the difference between the target value and the actual machining gap; if the actual machining gap of the block electrode 9 is larger than the target value of the block electrode 9 in this round of compensation electrolytic machining, the block electrode 9 is retracted by the difference between the target value and the actual machining gap; when a block electrode 9 is adjusted, it will no longer participate in the sorting of the difference between the actual machining gap and the target value after image capture processing in the next block adjustment of this round. Reference to the machining state of the block electrode in the block compensation electrolytic machining stage Figure 3 As shown, Figure 3 The left side is the initial processing time, and the right side is the processing end time;

[0049] Figure 6 In the process of block electrode compensation electrochemical machining experiment, the images of a block electrode at different machining periods were captured by CCD high-speed camera, which proved that the replication accuracy of the plane after block electrode compensation electrochemical machining was significantly improved;

[0050] The motion execution system includes an x-axis moving unit, a motion platform 6, a fixed platform 5, a dual-axis moving unit, a grabbing robot and a pulse power supply 27; specifically, the x-axis moving unit includes a motor 41, a guide rail 40, a lead screw 39, a bearing seat and a slider, and the motor 41 of the x-axis moving unit receives a control signal from the motion control unit 25 to drive the motion platform 6 and the tool cathode 10 to perform a feeding processing motion at a constant speed in the x-axis direction, that is, a pre-forming electrolytic processing motion; the dual-axis moving unit and the fixed guide rail 7 are fixed on the motion platform 6; the fixed platform 5 is located at the bottom of the entire device;

[0051] Specifically, the dual-coordinate moving unit includes a longitudinal motor 28, a longitudinal guide rail 29, a longitudinal lead screw 30, a longitudinal bearing seat 31, a longitudinal slider and a transverse guide rail 38, a transverse motor 37, a transverse slider 36, a transverse lead screw 33, and a transverse bearing seat 32; the longitudinal motor 28 of the dual-coordinate moving unit receives a motion command issued by the motion control unit 25 to move the transverse guide rail 38 to a specified block area, and the transverse motor 37 of the dual-coordinate moving unit receives a motion command issued by the motion control unit 25 to move the grasping robot to the grasping position of the corresponding grasping slider 8;

[0052] Specifically, the grasping robot includes a mechanical claw 34 and a mechanical arm 35. The two sides of the mechanical arm 35 are fixedly connected to the mechanical claw 34 and the horizontal slider 36 respectively. The two inner sides of the mechanical claw 34 are provided with position sensors. When the mechanical claw 34 moves to the position sensor provided on the grasping slider 8, the mechanical claw 34 immediately grasps the grasping slider 8 accurately and performs block compensation electrolytic machining movement; the positive pole of the pulse power supply 27 is connected to the workpiece 3, and the negative pole is connected to the block electrode 9 to provide energy for electrolytic machining;

[0053] The fixed adjustment system includes an adjustment frame 2, an electrolytic cell 4, a fixed guide rail 7 and a grabbing slider 8; the adjustment frame 2 adjusts and fixes the workpiece 3 to the initial processing position; the top of the electrolytic cell 4 is a transparent glass cover, which not only plays a sealing role, but also provides a field of view for the CCD high-speed camera 1 to capture images. A dedicated flow channel is arranged between the workpiece 3 and the cathode in the electrolytic cell 4 to ensure the smooth flow of the electrolyte; the fixed guide rail 7 is neatly installed on the motion platform 6 with the same gap, and the grabbing slider 8 is installed on the top. The fixed guide rail 7 not only guides the feed compensation movement of the block electrode 9, but also connects the block electrodes tightly together, so that all the block electrodes 9 can accurately form the integral forming tool cathode 10 during the initial processing; the grabbing slider 8 is installed on the corresponding fixed guide rail 7, the grabbing slider 8 is fixedly connected to the block electrode 9 on it, and position sensors are arranged on both sides of each grabbing slider 8 to ensure that the grabbing robot can accurately grab it;

[0054] The electrolyte circulation system includes a temperature control unit 17, an electrolyte tank 14, a liquid inlet pipe 15, a hydraulic pump 16, a liquid inlet filter 18, a pressure gauge 19, a one-way valve 20, a liquid outlet pipe 11, a liquid outlet filter 12 and a waste liquid tank 13; the electrolyte circulation system provides a high-voltage electrolyte with a constant temperature for the entire electrolytic machining device, ensures that the electrolytic products of the workpiece in the machining area and the cathode gap are discharged smoothly, and recycles the waste liquid after electrolytic machining;

[0055] The real-time monitoring system includes a data acquisition card 23, a temperature sensor 21, a pressure sensor 22 and a current sensor 26; the temperature sensor 21, the pressure sensor 22 and the current sensor 26 monitor the temperature, electrolyte pressure and current parameters of the entire electrolytic machining process in real time. When any parameter is abnormal, the detection signal is transmitted back to the data acquisition card 23, and the data is transmitted to the computer 24. The computer 24 issues a control instruction to interrupt the feed motion and turn off the pulse power supply 27 switch to avoid damage to the device due to a short circuit between the workpiece and the cathode.

[0056] A method for self-regulating electrolytic machining of block electrodes controlled by machine vision, comprising the following steps:

[0057] S1: The block electrode 9 is fixedly connected to the grab slide block 8, and the grab slide block 8 is installed on the corresponding fixed guide rail 7, and the relative position of the block electrode 9 is adjusted on the fixed guide rail 7 to accurately form the integral forming tool cathode 10; the integral forming tool cathode 10 and the workpiece 3 are moved to the initial processing position by adjusting the moving platform 6 and the adjusting frame 2, and the minimum processing gap between the two is ensured to be the balanced processing gap of the processing material;

[0058] S2: storing the balance machining gap of the workpiece, the error threshold of the pre-forming electrolytic machining stage, the error threshold of the block compensation machining stage and the coordinates of the ideal machining contour line of the workpiece in the computer 24; focusing the CCD high-speed camera 1 on the boundary between the workpiece 3 and the cathode 10 of the integral forming tool, performing light control processing on the entire electrolytic machining area to ensure correct exposure, reduce noise, and finally capture a high-quality image;

[0059] S3: Pre-forming electrolytic machining stage: turn on the pulse power supply 27 and the electrolyte circulation system, the computer 24 sends instructions to the motion control unit 25 to control the motor 41 of the x-axis moving unit to drive the motion platform 6 and the integral forming tool cathode 10 to perform feeding processing movement in the x-axis direction at a constant speed; during the processing of this stage, the CCD high-speed camera 1 captures the image of the processing area in real time and transmits it to the image processing unit of the computer 24, the image processing unit analyzes and processes the image and scans line by line to obtain the actual processing gap of each scanning line between the workpiece 3 and the integral forming tool cathode 10, and subtracts it from the balanced processing gap, compares the difference and the error threshold of the pre-forming electrolytic machining stage, and uses this as the criterion for the end of the pre-forming electrolytic machining stage; if the difference between the actual processing gap and the balanced processing gap of all scanning lines is less than the error threshold of the pre-forming electrolytic machining stage, the pre-forming electrolytic machining stage ends; the processing state reference of the pre-forming electrolytic machining stage Figure 2 As shown;

[0060] S4: Block compensation electrochemical machining stage: The x-axis constant speed feed machining motion of the preforming electrochemical machining stage continues; at the beginning of each round of compensation electrochemical machining, the image is first captured and processed, and after the actual machining contour line of the workpiece at the machining moment is extracted, the difference between the theoretical contour line corresponding to the data points pre-stored in the computer 24 is calculated. If the difference of all data points is within the preset error threshold, the block compensation electrochemical machining stage ends, otherwise the actual machining gap of each block area at that moment is calculated, and the difference between the actual machining gap of each block area and the target value is calculated, and the difference with the largest absolute value is selected for adjustment. The corresponding block electrode 9; the principle of adjusting each block electrode 9 is: if the actual machining gap of the block electrode 9 is less than the target value of the block electrode 9 in this round of compensation electrolytic machining, the block electrode 9 is fed forward by the difference between the target value and the actual machining gap; if the actual machining gap of the block electrode 9 is greater than the target value of the block electrode 9 in this round of compensation electrolytic machining, the block electrode 9 is retracted by the difference between the target value and the actual machining gap; when a block electrode 9 is adjusted, it will no longer participate in the sorting of the difference between the actual machining gap and the target value after image capture processing in the next block adjustment of this round. Reference to the machining state of the block electrode in the block compensation electrolytic machining stage Figure 3 As shown;

[0061] S5: Turn off the pulse power supply 27, the temperature control unit 17, the hydraulic pump 16 and the machine vision system, remove the workpiece 3, and complete the processing of the self-adjusting electrolytic replication forming of the block tool electrode controlled by the machine vision.

[0062] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0063] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A block electrode self-adjusting electrolytic machining device controlled by machine vision, characterized in that: The invention comprises a machine vision system, a motion execution system, a fixed adjustment system, an electrolyte circulation system and a real-time monitoring system; wherein the machine vision system comprises a CCD high-speed camera (1), a computer (24) and a motion control unit (25); the CCD high-speed camera (1) captures a real-time image of a processing area, the computer (24) analyzes and processes the captured image and calculates the actual processing gap between the workpiece (3) and the tool cathode (10), the computer (24) compares and calculates the processing gap and the target value according to the logical relationship of a set program, and then sends a control instruction to the motion control unit (25), the motion control unit (25) sends a motion instruction to the motion execution system, and the motion execution system drives the tool cathode (10) to work; the electrolyte circulation system is used to provide electrolyte; the real-time monitoring system is used to monitor the current, electrolyte pressure and temperature parameters in real time, and when any parameter is abnormal, transmits information to the computer (24) and sends a control instruction to interrupt the feeding motion and turn off the pulse power supply (27); the fixed adjustment system adjusts the workpiece (3) and the tool cathode (10) to the processing position and fixes them.

2. The machine vision controlled self-adjusting electrolytic machining device of block electrodes according to claim 1, characterized in that: The tool cathode (10) comprises several segmented electrodes (9), and the motion execution system provides pre-forming electrolytic machining motion for the tool cathode (10) and segmented compensating electrolytic machining motion for the segmented electrodes (9).

3. The machine vision controlled self-adjusting electrolytic machining device of block electrodes according to claim 2, characterized in that: The contacting sides of adjacent segmented electrodes (9) are insulated and lubricated, so that the segmented electrodes (9) can form a tool cathode (10) and perform pre-forming electrolytic machining, and a single segmented electrode (9) can be used as a basic machining unit to perform segmented compensatory electrolytic machining on the workpiece (3). The actual machining gap of the compensatory electrolytic machining movement of each segmented electrode (9) is calculated in real time by the machine vision system, and after comparison and calculation according to the logical relationship of the set program, an instruction is issued to control the specified segmented electrode (9) to perform segmented compensatory electrolytic machining.

4. The machine vision controlled self-adjusting electrolytic machining device of segmented electrodes according to claim 2, characterized in that: The motion execution system comprises an x-axis moving unit, a motion platform (6), a fixed platform (5), a dual-coordinate axis moving unit, a grasping robot and a pulse power supply (27); the x-axis moving unit receives a motion instruction from a motion control unit (25), and provides a feeding motion in the x-axis direction of the motion platform (6), thereby providing a pre-forming electrolytic machining motion for the tool cathode (10); the dual-coordinate axis moving unit receives a motion instruction from the motion control unit (25), moves the grasping robot to a specified grasping position, and then adjusts the block electrode (9), thereby providing a block compensation electrolytic machining motion for the block electrode (9); the positive pole of the pulse power supply (27) is connected to the workpiece (3), and the negative pole is connected to the block electrode (9), thereby providing energy for electrolytic machining.

5. The machine vision controlled self-adjusting electrolytic machining device of segmented electrodes according to claim 1, characterized in that: The fixed adjustment system comprises an electrolytic cell (4), an adjustment frame (2), a fixed guide rail (7) and a plurality of grabbing slide blocks (8); a transparent glass cover is arranged above the electrolytic cell (4); the adjustment frame (2) adjusts and fixes the workpiece (3); the fixed guide rail (7) not only provides a guiding function for the compensating movement of the segmented electrodes (9), but also closely arranges the segmented electrodes (9) to form an integral forming tool cathode (10); the grabbing slide block (8) is fixedly connected to the segmented electrodes (9), and position sensors are arranged on both sides of the grabbing slide block (8) so that it can be grabbed by a grabbing robot.

6. The machine vision controlled self-adjusting electrolytic machining device of segmented electrodes according to claim 1, characterized in that: The electrolyte circulation system comprises an electrolyte tank (14), a temperature control unit (17), a liquid inlet pipe (15), a hydraulic pump (16), a liquid inlet filter (18), a pressure gauge (19), a one-way valve (20), a liquid outlet pipe (11), a liquid outlet filter (12) and a waste liquid tank (13); the electrolyte tank (14) is provided with a temperature control unit (17), the temperature control unit (17) is used to adjust the temperature of the electrolyte tank (14); one end of the liquid inlet pipe (15) is arranged in the electrolyte tank (14), and the other end is placed at the processing position of the workpiece (3); the liquid inlet pipe (15) is provided with a hydraulic pump (16), a liquid inlet filter (18), a pressure gauge (19) and a one-way valve (20) in sequence; the electrolyte after the electrolytic chemical reaction flows into the waste liquid tank (13) through the liquid outlet pipe (11) and the liquid outlet filter (12).

7. The machine vision controlled self-adjusting electrolytic machining device of segmented electrodes according to claim 6, characterized in that: A pressure sensor (22) and a temperature sensor (21) are provided near the outlet of the liquid inlet pipe (15). The pressure sensor (22) and the temperature sensor (21) are used to monitor the temperature and pressure of the electrolyte at the outlet, respectively. The pressure sensor (22) and the temperature sensor (21) are electrically connected to a data acquisition card (23).

8. The machine vision controlled self-adjusting electrolytic machining device of block electrodes according to claim 1, characterized in that: The computer (24) analyzes and processes the captured image, specifically including the principle of detecting the actual machining gap between the workpiece (3) and the cathode, which is to find the grayscale jump position of the image grayscale matrix, specifically, grayscale conversion, median filter preprocessing, threshold segmentation conversion to binary image, morphological filter opening operation and Canny edge detection processing are respectively adopted for the image, and the final transformation result of the image is to form a smooth boundary between the anode and the cathode, the boundary of the two electrodes is set to white, and the other areas are set to black. The transformed image is scanned line by line to obtain the pixel width of different scanning lines, and the actual machining gap of different scanning lines is calculated by corresponding ratio; the pre-forming electrolytic machining movement and the block compensation electrolytic machining movement are both controlled by the machine vision system.

9. The processing method of the block electrode self-adjusting electrolytic processing device controlled by machine vision according to any one of claims 1 to 8, characterized in that: It includes a pre-forming electrolytic machining stage and a block compensation electrolytic machining stage; Pre-forming electrolytic machining stage: the computer (24) sends instructions to the motion control unit (25) to control the motion platform (6) and the tool cathode (10) to perform feeding machining motion at a constant speed in the x-axis direction; at the same time, the machine vision system captures, processes and scans the image information of the machining area line by line in real time, calculates the actual machining gap of all scanning lines of the workpiece (3) and the tool cathode (10), and then makes a difference with the balance machining gap respectively, compares the difference of the scanned line with the error threshold of the pre-forming electrolytic machining stage, and uses this as a criterion for the end of the pre-forming electrolytic machining stage. If the difference of all scanning lines is less than the error threshold, the pre-forming electrolytic machining stage ends; Block compensation electrochemical machining stage: the x-axis constant speed feed machining motion of the preforming electrochemical machining stage continues; the block compensation electrochemical machining stage is divided into different rounds for block adjustment. In each round of block compensation electrochemical machining, each block electrode (9) has a basis for forward feeding or backward retreat in that round, that is, the target value of that round of block compensation electrochemical machining. The target value of the first round of compensation electrochemical machining is the balanced machining gap. The target value of each subsequent round of compensation electrochemical machining is the actual machining gap of each block area calculated after the first image capture in the previous round of compensation electrochemical machining. In each round of compensation electrolytic machining, each block electrode (9) is adjusted only once, and is adjusted one by one in the order of the absolute value of the difference between the block electrode (9) and the target value corresponding to the round; specifically, at the beginning of each round of compensation electrolytic machining, the image is first captured and processed, and after the actual machining contour line of the workpiece at the machining moment is extracted, the difference between the data points corresponding to the theoretical contour line pre-stored in the computer (24) is calculated; if the difference of all data points is within a preset error threshold, the block compensation electrolytic machining stage ends; otherwise, the actual machining gap of each block area at the moment is calculated, and the difference between the actual machining gap of each block area and the target value is calculated, and the block electrode (9) corresponding to the difference with the largest absolute value is selected; the calculation method of the actual machining gap of the block electrode (9) is to select four scanning lines that divide the block area into five small areas of equal width, calculate the actual machining gaps corresponding to the four scanning lines and take the average value, and the calculated average value is the actual machining gap between the block electrode (9) and the workpiece (3).

10. The processing method according to claim 9, characterized in that: The principle of block adjustment is: if the actual machining gap of the block electrode (9) is smaller than the target value of the block electrode (9) in this round of compensation electrolytic machining, the block electrode (9) is fed forward by the distance of the difference between the target value and the actual machining gap; if the actual machining gap of the block electrode (9) is larger than the target value of the block electrode (9) in this round of compensation electrolytic machining, the block electrode (9) is retracted by the distance of the difference between the target value and the actual machining gap; when a block electrode (9) is adjusted, it will no longer participate in the sorting of the difference between the actual machining gap and the target value after image capture processing in the next block adjustment of this round.

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