A method and device for electrolytic machining of a special-shaped curved surface by localized adaptive mixing of powders
By setting a micro-column electromagnet array at the cathode end of the electrolytic grinding head and adjusting the excitation current in real time, the problem of difficult machining of irregular curved surfaces in traditional electrolytic grinding is solved, and high-precision and stable electrolytic machining of irregular curved surfaces is realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG UNIV
- Filing Date
- 2026-03-30
- Publication Date
- 2026-05-29
AI Technical Summary
Traditional electrolytic grinding is difficult to effectively process complex irregular curved surfaces, and existing methods have limitations in improving the electrolytic machining of complex curved surfaces.
A micro-column electromagnet array is set at the cathode end of the electrolytic grinding head. By adaptively controlling the excitation current of each column electromagnet, a non-uniform magnetic field is formed, so that the magnetic abrasive particles are gradient distributed in the electrolyte, fitting the contour shape of the irregular curved surface, and the excitation current is adjusted in real time to maintain the adsorption stability of the abrasive particles.
It achieves high-precision electrolytic machining of irregular curved surfaces, breaks through the limitations of traditional tool shapes, enhances the localization and stability of machining, and can adapt to the machining of complex curved surfaces with arbitrary curvature changes.
Smart Images
Figure CN122099459A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrolytic grinding technology, and particularly relates to a method and apparatus for localized adaptive powder mixing electrolytic machining of irregular curved surfaces. Background Technology
[0002] Electrolytic grinding is a special machining technology that combines electrochemical action with mechanical grinding. During processing, the workpiece is connected to the positive terminal of the power supply, and the conductive grinding wheel is connected to the negative terminal of the power supply. The rotating grinding wheel continuously removes the electrolytic products on the surface of the workpiece, thereby achieving the purpose of material removal. It has the advantages of high machining accuracy and no residual stress or thermal damage.
[0003] However, due to the limitations of grinding wheel shape, electrolytic grinding can only process simple surfaces such as planes and cylinders. Traditional grinding wheel-based electrolytic grinding is inadequate for complex, irregularly shaped curved surfaces. To address this, many researchers have conducted studies. For example, patent CN113151887A uses a rotating workpiece (actually an anode) in an electrolyte solution to achieve a polishing effect. This method is only effective for rotating parts with high symmetry and is difficult to use for plate-like parts. Another example is patent CN203451643U, which proposes a method using a pleated nozzle to spray electrolyte onto a curved surface, thereby unifying the electrolytic polishing process at multiple points and improving polishing consistency. However, due to the limited number of pleated nozzles, this method can only improve the uniformity of electrolytic polishing of curved surfaces to a certain extent. While such methods have made some progress in improving the electrolytic machining of complex curved surfaces, they still have limitations in terms of workpiece shape, basic equipment, and the degree of improvement. Summary of the Invention
[0004] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a method and apparatus for localized adaptive mixed powder electrolytic machining of irregular curved surfaces. By adaptively controlling the micro-pillar electromagnet array to generate a non-uniform magnetic field, the magnetic abrasive gradient distribution fits the surface contour, thereby achieving high localization and high precision electrolytic machining of irregular curved surfaces.
[0005] Technical solution: To achieve the above objectives, the present invention provides a method for localized adaptive powder mixing electrolytic machining of irregular curved surfaces, comprising:
[0006] A micro-pillar electromagnet array is set at the cathode end of the electrolytic grinding head;
[0007] Obtain local curvature information of the irregular curved surface to be processed;
[0008] Based on the local curvature information, the excitation current of each columnar electromagnet in the micro-column electromagnet array is adaptively adjusted to form a non-uniform magnetic field at the cathode end of the electrolytic grinding head that matches the local curvature information.
[0009] An electrolyte mixed with magnetic abrasive particles is supplied to the area to be processed, so that the magnetic abrasive particles form a gradient distribution on the cathode surface of the electrolytic grinding head under the action of the non-uniform magnetic field, and fit the contour shape corresponding to the area to be processed.
[0010] The electrolytic grinding head is driven to perform electrolytic grinding on the irregular curved surface.
[0011] Furthermore, the micro-column electromagnet array is arranged in a circular pattern, with each column electromagnet having a diameter of 3-5 mm and a circumferential spacing of 1-2 mm between adjacent column electromagnets; the distance between the cathode of the electrolytic grinding head and the highest point of the irregular curved surface to be processed is 1-2 mm.
[0012] Furthermore, the magnetic abrasive grains consist of a magnetic matrix and a hard inlay covering the outside of the magnetic matrix, with a grain size of 150 μm.
[0013] Furthermore, adaptively adjusting the excitation current of each columnar electromagnet in the micro-column electromagnet array includes:
[0014] Real-time detection of electrolytic current signals during electrolytic processing;
[0015] Based on the comparison between the electrolytic current signal and the preset current threshold, the excitation current is dynamically adjusted to maintain the adsorption stability of the non-uniform magnetic field on the magnetic abrasive particles.
[0016] Furthermore, the electrolytic grinding process includes: controlling the electrolytic grinding head to move along a preset path, and during the movement, updating the excitation current of the micro-pillar electromagnet array in real time according to the curvature changes at different positions of the irregular curved surface, so that the gradient distribution of the magnetic abrasive grains dynamically matches the contour shape of the current processing area as the processing position changes.
[0017] A localized adaptive powder mixing electrolytic processing device for irregular curved surfaces includes:
[0018] A base, on which a three-axis moving mechanism is provided;
[0019] A special fixture is set on the machine base for clamping irregular curved surface workpieces to be processed;
[0020] An electrolytic grinding head is connected to the three-axis moving mechanism. The electrolytic grinding head includes a grinding head body and a micro-column electromagnet array disposed at one end of the grinding head body near the processing area. The micro-column electromagnet array is used to generate a non-uniform magnetic field under the control of the excitation current.
[0021] A powder-mixed electrolyte generating device is used to generate an electrolyte mixed with magnetic abrasive particles and deliver it to the electrolytic grinding head;
[0022] A control unit, electrically connected to the micro-column electromagnet array, is configured to: acquire local curvature information of the irregular curved surface workpiece, and adaptively adjust the excitation current of each column electromagnet in the micro-column electromagnet array according to the local curvature information, so that the micro-column electromagnet array generates a non-uniform magnetic field that matches the local curvature information, so as to adsorb the magnetic abrasive particles onto the cathode surface of the electrolytic grinding head to form a gradient distribution and fit the contour shape of the corresponding processing area.
[0023] Furthermore, the micro-column electromagnet array includes multiple columnar electromagnets arranged along the circumferential direction; each columnar electromagnet is fitted with a steel sleeve, and a sealing plug is provided at the upper end of the steel sleeve; the columnar electromagnets, the steel sleeves, and the sealing plugs together constitute an electromagnet assembly, and the electromagnet assembly is installed in the circumferential holes of the multi-hole plastic box of the electrolytic grinding head.
[0024] Furthermore, the electrolytic grinding head also includes a grinding head connector, a joint, a copper electrode, a conduit, and a sealing ring;
[0025] The three-axis moving mechanism is a three-axis servo slide module composed of an X-axis servo slide, a Y-axis servo slide, and a Z-axis servo slide. The grinding head connector is connected to the slider of the Z-axis servo slide, and a flow channel is opened inside the grinding head connector. The connector is set on the grinding head connector for receiving the mixed powder electrolyte output by the mixed powder electrolyte generating device. The perforated plastic box is set at the end of the grinding head connector and contains the micro-column electromagnet array. The copper electrode is set at the end of the perforated plastic box for forming an electrolytic circuit with the irregular curved surface workpiece. The conduit is set through the central axis of the perforated plastic box. The sealing ring is pressed against the position where the flow channel and the conduit are connected. The connector, the flow channel in the grinding head connector, and the conduit are sequentially connected to form a flow channel for the mixed powder electrolyte in the electrolytic grinding head. The liquid outlet end of the conduit passes through the copper electrode for spraying the mixed powder electrolyte into the processing area.
[0026] Furthermore, the special fixture includes a fixture body, a positioning key, a positioning permanent magnet, a support plate, a support block, and a clamping screw; the positioning key is located at the bottom of the fixture body and is used to cooperate with the T-slot of the machine base to achieve Y-direction positioning; the positioning permanent magnet is fixed to the positioning hole of the machine base by a first screw and is used to cooperate with the fixture body to achieve X-direction positioning; the support plate and the support block are set on the fixture body and are used to support the irregular curved surface workpiece; the clamping screw is used to press and fix the irregular curved surface workpiece to the fixture body; the machine base is provided with a drainage slope and a drainage hole.
[0027] Furthermore, the mixed electrolyte generating device includes an electrolyte generating pipeline and a slurry generating pipeline, both of which are connected to the mixing chamber at their ends, and the mixing chamber is connected to the connector via an output pipeline;
[0028] The electrolyte generation pipeline is sequentially equipped with a first water pump, a first check valve, a gas-liquid booster pump, a second check valve, an accumulator, a first pressure gauge, a pressure regulating valve, and a second pressure gauge. The air inlet of the gas-liquid booster pump is connected to an air compressor source.
[0029] A mixing agitator and a flow control valve are sequentially installed on the slurry generation pipeline, and the starting end of the slurry generation pipeline is connected to a second water pump and a magnetic abrasive source.
[0030] The mixing agitator is used to mix magnetic abrasive particles with water to form a mixed slurry. The gas-liquid booster pump and accumulator are used to generate an electrolyte with a preset pressure. The mixing chamber is used to mix the mixed slurry and the electrolyte to form a mixed powder electrolyte.
[0031] Beneficial Effects: This invention, by setting a micro-pillar electromagnet array at the cathode end of the electrolytic grinding head and independently controlling the excitation current of each electromagnet based on the local curvature information of the irregular curved surface to be processed, forms a non-uniform magnetic field that matches the curvature distribution of the surface. This non-uniform magnetic field acts on the magnetic abrasive grains mixed in the electrolyte, causing the abrasive grains to form a gradient distribution on the cathode surface, actively fitting the contour shape of the processing area. This breaks through the limitation of traditional electrolytic grinding relying on fixed-shape tools and can adapt to irregular curved surfaces with arbitrary curvature changes. At the same time, the magnetic abrasive grains are confined to the preset processing area under the constraint of the magnetic field, effectively suppressing the lateral diffusion of the electrolyte and significantly enhancing the localization of electrolytic processing. By detecting the electrolytic current in real time and dynamically adjusting the excitation current, a closed-loop control is formed, further ensuring the stability of abrasive grain adsorption during processing. In addition, the circumferentially arranged micro-pillar electromagnet structure can generate a continuously changing circumferential magnetic field gradient, which, combined with the movement of the grinding head along a preset path, achieves accurate fitting and efficient processing of complex curved surface contours. Attached Figure Description
[0032] Figure 1 A schematic diagram of the overall structure of the localized adaptive powder mixing electrolytic processing device for irregular curved surfaces;
[0033] Figure 2 This is a schematic diagram of the workpiece in its clamping state;
[0034] Figure 3 This is a cross-sectional structural diagram of an electrolytic grinding head;
[0035] Figure 4 This is a schematic diagram of the structure of an electrolytic grinding head from an axial side view.
[0036] Figure 5 This is a schematic diagram of the structure for processing and the distribution of magnetic abrasive particles;
[0037] Figure 6 This is a schematic diagram of the mixed powder electrolyte generation device. Detailed Implementation
[0038] The invention will now be further described with reference to the accompanying drawings.
[0039] like Figure 1 As shown, a method for localized adaptive mixed-powder electrolytic machining of irregular curved surfaces includes: setting a micro-column electromagnet array at the cathode end of an electrolytic grinding head; acquiring local curvature information of the area to be machined on the irregular curved surface; adaptively adjusting the excitation current of each columnar electromagnet in the micro-column electromagnet array according to the local curvature information to form a non-uniform magnetic field at the cathode end of the electrolytic grinding head that matches the local curvature information; supplying an electrolyte mixed with magnetic abrasive particles to the area to be machined, so that the magnetic abrasive particles form a gradient distribution on the cathode surface of the electrolytic grinding head under the action of the non-uniform magnetic field, fitting the contour shape corresponding to the area to be machined; and driving the electrolytic grinding head to perform electrolytic grinding on the irregular curved surface. Each columnar electromagnet in the micro-column electromagnet array can independently control the excitation current. When current passes through a columnar electromagnet, a magnetic field is generated around it, and the magnetic field strength is positively correlated with the current magnitude. Since the electromagnets are arranged in an array in space, the magnetic fields they generate are superimposed in space to form a non-uniform magnetic field with a specific distribution pattern. Different locations on the irregular curved surface have different radii of curvature, and the curvature information characterizes the degree and direction of curvature in local areas. Using this curvature information as a control input, the excitation current of each electromagnet is differentiated. Regions with larger curvature correspond to larger currents to generate stronger magnetic fields, while regions with smaller curvature correspond to smaller currents. The resulting spatial distribution of the non-uniform magnetic field matches the curvature distribution of the surface. Magnetic abrasive particles mixed into the electrolyte are subjected to magnetic force in the magnetic field, with the direction of the force along the magnetic field gradient and its magnitude proportional to the gradient. In the non-uniform magnetic field, the abrasive particles experience different magnetic forces at different locations; regions with stronger magnetic fields have higher abrasive particle density, while regions with weaker magnetic fields have lower density, thus forming a density gradient distribution on the cathode surface. The envelope contour of this gradient distribution corresponds to the curvature distribution of the surface, achieving a fitting of the surface contour. This invention, by actively controlling the abrasive particle distribution with a magnetic field to adapt to the curvature of the surface, overcomes the limitations of traditional electrolytic grinding that relies on fixed-shape tools, and can adapt to irregular curved surfaces with arbitrary curvature variations.
[0040] The micro-column electromagnet array is arranged circumferentially, with each column electromagnet having a diameter of 3-5 mm and a circumferential spacing of 1-2 mm between adjacent column electromagnets. The distance between the cathode of the electrolytic grinding head and the highest point of the irregular curved surface to be processed is 1-2 mm. This circumferential arrangement ensures that the column electromagnets are distributed in a ring around the grinding head axis, resulting in a continuously varying magnetic field in the circumferential direction, which can fit the surface features where curvature varies circumferentially. The diameter of the column electromagnet determines the spatial range of the magnetic field generated by a single electromagnet; a diameter of 3-5 mm ensures both the feasibility of the electromagnet winding process and matches the range of action of a single electromagnet with the characteristic scale of surface curvature changes. The circumferential spacing between adjacent electromagnets determines the spatial resolution of the magnetic field; a spacing of 1-2 mm ensures a smooth transition of the magnetic field generated by adjacent electromagnets without significant magnetic field discontinuities or abrupt changes, resulting in a continuous variation in the abrasive gradient distribution. The machining gap is the vertical distance between the cathode surface and the workpiece surface. A gap of 1-2 mm is within the typical gap range of electrolytic machining. Under this gap, the electrolyte can flow normally and undergo electrochemical reactions. At the same time, the magnetic field attenuates less in the air, which can generate sufficient adsorption force on the abrasive particles to overcome the drag force of the electrolyte flow, ensuring that the abrasive particles are effectively adsorbed and maintain a stable distribution.
[0041] The magnetic abrasive grains consist of a magnetic matrix and a hard inlay covering the magnetic matrix, with a grain size of 150 μm. The magnetic matrix is made of ferromagnetic materials such as iron, cobalt, and nickel, which can be magnetized and subjected to magnetic force in a magnetic field, forming the basis for the controllable adsorption of the abrasive grains. The external hard inlay is made of high-hardness materials such as alumina, diamond, and silicon carbide, which comes into contact with the workpiece surface during electrolytic grinding and removes the passivation film and surface material generated by the electrolytic reaction through mechanical action. During electrolytic machining, the workpiece acts as the anode and undergoes a dissolution reaction, forming a passivation film or reaction products on its surface. This layer hinders further electrochemical dissolution. The scraping action of the hard inlay can remove this layer in a timely manner, exposing the new metal matrix to the electrolyte and ensuring the continuous electrochemical reaction. The 150 μm abrasive grains achieve a balance between magnetic response capability, suspension stability, and cutting capability: if the grain size is too small, the magnetic response capability will be insufficient and it will be prone to agglomeration; if the grain size is too large, it may scratch the workpiece surface and it will be difficult to form a fine gradient distribution in the magnetic field.
[0042] The adaptive adjustment of the excitation current of each columnar electromagnet in the micro-column electromagnet array includes: real-time detection of the electrolytic current signal during the electrolytic machining process; and dynamic adjustment of the excitation current based on the comparison result of the electrolytic current signal and a preset current threshold to maintain the adsorption stability of the non-uniform magnetic field on the magnetic abrasive particles. The electrolytic current is a comprehensive reflection of the machining gap state, and its magnitude is related to factors such as the machining gap width, electrolyte conductivity, abrasive particle distribution density, and workpiece anodic dissolution rate. When the abrasive particle adsorption state changes, the equivalent resistance in the machining gap changes, causing fluctuations in the electrolytic current. The preset current threshold is set based on the current range under stable machining conditions determined by process experiments. Real-time detection of the electrolytic current and comparison with the preset threshold indicate that the abrasive particle adsorption state has deviated from the stable machining range when the detected value exceeds the threshold range. In this case, the excitation current of the corresponding electromagnet is adjusted by the control unit to change the magnetic field strength, causing the abrasive particle adsorption state to change towards the stable range.
[0043] The electrolytic grinding process includes: controlling the electrolytic grinding head to move along a preset path, and during the movement, updating the excitation current of the micro-pillar electromagnet array in real time according to the curvature changes at different positions of the irregular curved surface, so that the gradient distribution of the magnetic abrasive grains dynamically matches the contour shape of the current processing area as the processing position changes. The control unit calculates the local curvature information corresponding to the current processing position in advance or in real time according to the preset processing path, and converts the curvature information into excitation current commands for each electromagnet. When the grinding head moves to a new processing position, the excitation current is updated synchronously, and the magnetic field distribution changes accordingly, ensuring that the gradient distribution of abrasive grains on the cathode surface always matches the surface contour at the current position. This achieves continuous fitting processing of the entire complex curved surface, avoiding the seam marks and uneven transitions that may occur with segmented processing, and ensuring the consistency and continuity of the curved surface processing.
[0044] like Figure 1 , Figure 3 , Figure 4 as well as Figure 5As shown, a localized adaptive mixed-powder electrolytic machining device for irregular curved surfaces includes: a base 1, on which a three-axis moving mechanism is mounted; a special fixture 2, mounted on the base, for clamping the irregular curved surface workpiece 24 to be processed; an electrolytic grinding head 3, connected to the three-axis moving mechanism, the electrolytic grinding head 3 including a grinding head body and a micro-column electromagnet array 3.1 disposed at one end of the grinding head body near the processing area, the micro-column electromagnet array 3.1 being used to generate a non-uniform magnetic field under the control of an excitation current; and a mixed-powder electrolyte generation device for generating a mixture of magnetic abrasive particles. The electrolyte is supplied to the electrolytic grinding head 3; the control unit, electrically connected to the micro-column electromagnet array 3.1, is configured to: acquire the local curvature information of the irregular curved surface workpiece 24, and adaptively adjust the excitation current of each columnar electromagnet 327 in the micro-column electromagnet array 3.1 according to the local curvature information, so that the micro-column electromagnet array 3.1 generates a non-uniform magnetic field that matches the local curvature information, so as to adsorb the magnetic abrasive particles 4 onto the cathode surface of the electrolytic grinding head 3 to form a gradient distribution and fit the contour shape of the corresponding processing area. The control unit, as the core control node, stores or receives the three-dimensional model data of the irregular curved surface workpiece 24, obtains the curvature information of each point on the surface by analyzing the model, and converts the curvature information into excitation current commands for each electromagnet. The three-axis moving mechanism provides the relative motion degrees of freedom between the grinding head and the workpiece, enabling the grinding head to scan the entire processing surface according to a preset trajectory. The micro-column electromagnet array 3.1 is positioned at the end of the grinding head body near the machining area, shortening the magnetic field's effective distance and reducing its attenuation in the air, ensuring a sufficiently strong magnetic field acts on the magnetic abrasive grains in the machining gap. The powder-mixing electrolyte generator continuously supplies electrolyte containing magnetic abrasive grains, providing both the reaction medium and the grinding medium for machining. The electrical connection between the control unit and the micro-column electromagnet array 3.1 employs a multi-channel independent control method, ensuring that the current of each electromagnet can be individually adjusted.
[0045] The control unit is implemented as a circuit board, integrating a microcontroller, a memory chip, and a multi-channel current drive module. This control unit is housed within a controller box 39, which is fixed to the grinding head connector 30 of the electrolytic grinding head 3 with screws and sealed with a controller box cover to prevent electrolyte corrosion. Furthermore, the electrical connection harness between the control unit and the micro-pillar electromagnet array 3.1 uses shielded cables to ensure the control signal's anti-interference capability.
[0046] like Figure 3 , Figure 4 and Figure 5As shown, the micro-column electromagnet array 3.1 includes multiple columnar electromagnets 327 arranged circumferentially. Each columnar electromagnet 327 is fitted with a steel sleeve 326, and a sealing plug 328 is provided at the upper end of the steel sleeve 326. The columnar electromagnets 327, steel sleeves 326, and sealing plugs 328 together constitute an electromagnet assembly, which is installed in the circumferential holes of the perforated plastic housing 32 of the electrolytic grinding head 3. The steel sleeve 326 is made of magnetically conductive material and is fitted outside the columnar electromagnets 327, serving as magnetic shielding and magnetic circuit guidance. The magnetic lines of force generated by the columnar electromagnets 327 tend to close along paths with lower magnetic resistance. The steel sleeve 326 provides a low-resistance path, making the magnetic lines of force more concentrated along the sleeve axis, enhancing the magnetic field strength towards the processing area, and reducing magnetic field crosstalk between adjacent electromagnets, thus ensuring the control independence of each electromagnet. The sealing plug 328 is made of insulating material to prevent electrolyte from seeping into the interior through the gap between the columnar electromagnet 327 and the steel sleeve 326, thus avoiding short circuits or corrosion of the electromagnetic coil. The perforated plastic box 32, as the mounting base, is also made of insulating material. The diameter and positional accuracy of its circumferential hole array ensure the installation accuracy of each electromagnet assembly, and the insulating properties of the plastic prevent electrical interference between electromagnets and between the electromagnets and the electrolytic circuit. Furthermore, the modular installation of the entire electromagnet assembly facilitates assembly and maintenance.
[0047] like Figure 3 , Figure 4 and Figure 5 The electrolytic grinding head 3 also includes a grinding head connector 30, a joint 31, a copper electrode 33, a conduit 37, and a sealing ring 38; as shown Figure 1As shown, the three-axis moving mechanism is a three-axis servo slide module composed of an X-axis servo slide 11, a Y-axis servo slide 12, and a Z-axis servo slide 13. The grinding head connector 30 is connected to the slider of the Z-axis servo slide 13, and a flow channel is opened inside the grinding head connector 30. The connector 31 is disposed on the grinding head connector 30 and is used to connect the mixed electrolyte output by the mixed electrolyte generating device. The perforated plastic box 32 is disposed at the end of the grinding head connector 30 and contains the micro-column electromagnet array 3.1. The copper electrode 33 is disposed at the end of the perforated plastic box 32 to form an electrolytic circuit with the irregular curved workpiece 24; the conduit 37 is disposed through the central axis of the perforated plastic box 32; the sealing ring 38 is pressed against the position where the flow channel and the conduit 37 meet; the connector 31, the flow channel in the grinding head connector 30, and the conduit 37 are sequentially connected to form a flow channel for the mixed powder electrolyte in the electrolytic grinding head 3. The liquid outlet end of the conduit 37 passes through the copper electrode 33 and is used to spray the mixed powder electrolyte into the processing area. The grinding head connector 30 serves as a structural carrier, and the flow channel opened inside it realizes the integration of the electrolyte delivery path and the mechanical structure, avoiding interference of external pipelines with the processing motion. The X-axis servo slide, Y-axis servo slide, and Z-axis servo slide constitute a three-axis linkage system, which realizes high-precision positioning and movement of the electrolytic grinding head 3 in three-dimensional space through the precision transmission of servo motors and ball screws. Connector 31 uses a standard hydraulic interface for quick connection to the external liquid supply pipeline, ensuring the sealing of the mixed powder electrolyte delivery. The perforated plastic box 32 is located at the end of the grinding head connector 30, serving as the mounting base for the electromagnet assembly and copper electrode 33. Its axial length design ensures an appropriate distance between the electromagnet and the processing area. The copper electrode 33 is located at the end of the perforated plastic box, serving as the cathode of the electrolytic circuit. Its end face directly contacts the abrasive particle gradient distribution area, shortening the current path. A conduit runs through the central axis of the perforated plastic box, placing the liquid outlet at the center of the copper electrode 33. The mixed powder electrolyte is vertically sprayed from the center to the processing area, ensuring circumferential symmetry of the flow field distribution and uniform abrasive particle distribution under the combined action of the magnetic field and the flow field. A sealing ring 38 forms a seal at the junction of the flow channel and the conduit, preventing liquid leakage.
[0048] like Figure 4 As shown, the perforated plastic box 32 is specifically connected to the grinding head connector 30 via bolts 35 and nuts. The copper electrode 33 is fixedly connected to the perforated plastic box 32 via fastening screws.
[0049] for Figure 5 Further explanation: Figure 5This is a schematic diagram of the magnetic abrasive distribution in the machining machine. The mixed electrolyte, consisting of magnetic abrasive particles 4 and electrolyte 5, enters the electrolytic machining zone through the flow channel. Under the influence of the magnetic field of the micro-column electromagnet array 3.1 and the flow of electrolyte 5, the magnetic abrasive particles 4 form an effective adsorption zone 7 and a flow zone 8. The magnetic abrasive particles 4 in the effective adsorption zone 7 are adsorbed onto the cathode surface and form a gradient distribution that conforms to the contour of the machining surface. Therefore, the effective adsorption zone 7 can also be called the abrasive gradient distribution zone. The magnetic abrasive particles 4 in the flow zone 8 circulate in the machining gap under the constraint of the magnetic field.
[0050] like Figure 2 As shown, the special fixture 2 includes a fixture body 20, a positioning key 21, a positioning permanent magnet 22, a support plate 26, a support block 27, and a clamping screw 25; the positioning key 21 is located at the bottom of the fixture body 2 and is used to cooperate with the T-slot of the machine base 1 to achieve positioning in the Y direction; the positioning permanent magnet 22 is fixed to the positioning hole 16 of the machine base 1 by a first screw 23 and is used to cooperate with the fixture body 20 to achieve positioning in the X direction; the support plate 26 and the support block 27 are set on the fixture body 20 and are used to support the irregular curved surface workpiece 24; the clamping screw 25 is used to clamp and fix the irregular curved surface workpiece 24 to the fixture body 2; the machine base 1 is provided with a drainage slope 14 and a drainage hole 15.
[0051] like Figure 6 As shown, the mixed-powder electrolyte generating device includes an electrolyte generating pipeline a and a slurry generating pipeline b, both connected to a mixing chamber 9 at their ends. The mixing chamber 9 is connected to the connector 31 via an output pipeline c. The electrolyte generating pipeline a is sequentially equipped with a first water pump 91, a first one-way valve 92, a gas-liquid booster pump 93, a second one-way valve 94, an accumulator 95, a first pressure gauge 96, a pressure regulating valve 97, and a second pressure gauge 98. The air inlet of the gas-liquid booster pump 93 is connected to an air compressor source 99. The slurry generating pipeline b is sequentially equipped with a mixing agitator 9.3 and a flow control valve 9.4. The starting end of the slurry generating pipeline b is connected to a second water pump 9.1 and a magnetic abrasive source 9.2. The mixing agitator 9.3 is used to mix magnetic abrasive particles with water to form a mixed slurry. The gas-liquid booster pump 93 and the accumulator 95 are used to generate an electrolyte with a preset pressure. The mixing chamber 9 is used to mix the mixed slurry with the electrolyte to form a mixed powder electrolyte. The mixed powder electrolyte is sprayed out from the conduit 37. The spray pressure, abrasive particle concentration, etc. are measured experimentally according to the actual situation.
[0052] This embodiment takes the processing of a 316L stainless steel workpiece with a concave spherical surface as an example. The workpiece has dimensions of 540mm×340mm×50mm and a gently curved concave spherical surface. The magnetic abrasive is made of iron matrix and alumina hard inlay, with an average particle size of 150μm. The electrolyte is an aqueous solution of sodium nitrate.
[0053] First, the special fixture 2 is installed on the worktable of the machine base 1, so that the positioning key 21 at the bottom of the fixture 2 engages with the T-slot of the worktable to achieve positioning in the Y direction; at the same time, the positioning permanent magnet 22 engages with the positioning hole 16 of the worktable to achieve positioning in the X direction, thus completing the rapid and accurate positioning of the fixture. Then, the irregular curved workpiece 24 is placed on the support plate 26 and the support block 27, and the clamping screw 25 is tightened to clamp the workpiece.
[0054] The starting device controls the three-axis moving mechanism consisting of the X-axis servo slide 11, the Y-axis servo slide 12 and the Z-axis servo slide 13, so that the electrolytic grinding head 3 moves to the grinding starting point, and the Z-axis position is adjusted so that the distance between the cathode surface of the grinding head and the highest point of the processed surface is kept within 1~2mm.
[0055] The mixed powder electrolyte generating device is turned on to generate mixed powder electrolyte, which is then transported to the processing area and waits for the electrolyte spray to reach a stable state.
[0056] Connect the irregular curved workpiece 24 to the positive terminal of the power supply, and connect the copper electrode 33 on the grinding head to the negative terminal of the power supply, and adjust it to a suitable electrolysis voltage.
[0057] The control unit acquires the local curvature information of the irregular curved surface to be processed, and adaptively adjusts the excitation current of each columnar electromagnet 327 in the micro-column electromagnet array 3.1 according to the information, forming a non-uniform magnetic field at the cathode end that matches the local curvature. Under the action of this non-uniform magnetic field, the magnetic abrasive particles 4 in the mixed powder electrolyte are adsorbed on the cathode surface to form a gradient distribution, fitting the contour shape of the corresponding processing area.
[0058] After the abrasive particles have stabilized and formed an effective adsorption zone 7 (abrasive particle gradient distribution zone) and a flow zone 8, the electrolytic grinding head 3 moves along the Y direction at a speed of 5 mm / s. During the movement, the control unit updates the excitation current in real time according to the curvature changes at different positions on the surface, so that the gradient distribution of the magnetic abrasive particles dynamically matches the contour shape of the current processing area. When the grinding head moves to the other end of the workpiece, it moves one grinding head radius distance (80 mm) in the X direction, and then moves again in the opposite Y direction at a speed of 5 mm / s, repeating this process until the workpiece is finished.
[0059] During the processing, the control unit detects the electrolytic current signal in real time and compares it with the preset current threshold, dynamically adjusting the excitation current to maintain the adsorption stability of the non-uniform magnetic field on the magnetic abrasive particles.
[0060] After processing is completed, the control unit returns the grinding head to its origin, manually loosens the clamping screw 25, and removes the workpiece 24. The electrolyte that flows out during processing is collected by the drainage slope 14 and discharged from the drainage hole 15.
[0061] In summary, this invention, by setting a micro-pillar electromagnet array at the cathode end of the electrolytic grinding head and independently controlling the excitation current of each electromagnet based on the local curvature information of the irregular curved surface to be processed, forms a non-uniform magnetic field that matches the curvature distribution of the surface. This non-uniform magnetic field acts on the magnetic abrasive grains mixed in the electrolyte, causing the abrasive grains to form a gradient distribution on the cathode surface, actively fitting the contour shape of the processing area. This breaks through the limitation of traditional electrolytic grinding relying on fixed-shape tools and can adapt to irregular curved surfaces with arbitrary curvature changes. At the same time, the magnetic abrasive grains are confined to the preset processing area under the constraint of the magnetic field, effectively suppressing the lateral diffusion of the electrolyte and significantly enhancing the localization of electrolytic processing. By detecting the electrolytic current in real time and dynamically adjusting the excitation current, a closed-loop control is formed, further ensuring the stability of abrasive grain adsorption during processing. In addition, the circumferentially arranged micro-pillar electromagnet structure can generate a continuously changing circumferential magnetic field gradient, which, combined with the movement of the grinding head along a preset path, achieves accurate fitting and efficient processing of complex curved surface contours.
[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for localized adaptive powder mixing electrolytic machining of irregular curved surfaces, characterized in that: include: A micro-pillar electromagnet array is set at the cathode end of the electrolytic grinding head; Obtain local curvature information of the irregular curved surface to be processed; Based on the local curvature information, the excitation current of each columnar electromagnet in the micro-column electromagnet array is adaptively adjusted to form a non-uniform magnetic field at the cathode end of the electrolytic grinding head that matches the local curvature information. An electrolyte mixed with magnetic abrasive particles is supplied to the area to be processed, so that the magnetic abrasive particles form a gradient distribution on the cathode surface of the electrolytic grinding head under the action of the non-uniform magnetic field, and fit the contour shape corresponding to the area to be processed. The electrolytic grinding head is driven to perform electrolytic grinding on the irregular curved surface.
2. The method for localized adaptive powder mixing electrolytic machining of irregular curved surfaces according to claim 1, characterized in that: The micro-column electromagnet array is arranged in a circular pattern, with each column electromagnet having a diameter of 3-5 mm and a circumferential spacing of 1-2 mm between adjacent column electromagnets; the distance between the cathode of the electrolytic grinding head and the highest point of the irregular curved surface to be processed is 1-2 mm.
3. The method for localized adaptive powder mixing electrolytic machining of irregular curved surfaces according to claim 1, characterized in that: The magnetic abrasive grains consist of a magnetic matrix and a hard inlay covering the outside of the magnetic matrix, with a grain size of 150 μm.
4. The method for localized adaptive powder mixing electrolytic machining of irregular curved surfaces according to claim 1, characterized in that: Adaptively adjusting the excitation current of each columnar electromagnet in the micro-column electromagnet array includes: Real-time detection of electrolytic current signals during electrolytic processing; Based on the comparison between the electrolytic current signal and the preset current threshold, the excitation current is dynamically adjusted to maintain the adsorption stability of the non-uniform magnetic field on the magnetic abrasive particles.
5. The method for localized adaptive powder mixing electrolytic machining of irregular curved surfaces according to claim 1, characterized in that: The electrolytic grinding process includes: controlling the electrolytic grinding head to move along a preset path, and during the movement, updating the excitation current of the micro-column electromagnet array in real time according to the curvature changes at different positions of the irregular curved surface, so that the gradient distribution of the magnetic abrasive grains dynamically matches the contour shape of the current processing area as the processing position changes.
6. A localized adaptive powder mixing electrolytic processing device for irregular curved surfaces, characterized in that: include: A base (1) is provided with a three-axis moving mechanism; A special fixture (2) is set on the machine base for clamping the irregular curved surface workpiece (24) to be processed. An electrolytic grinding head (3) is connected to the three-axis moving mechanism. The electrolytic grinding head (3) includes a grinding head body and a micro-column electromagnet array (3.1) disposed at one end of the grinding head body near the processing area. The micro-column electromagnet array (3.1) is used to generate a non-uniform magnetic field under the control of the excitation current. A powder-mixed electrolyte generating device is used to generate an electrolyte mixed with magnetic abrasive particles and deliver it to the electrolytic grinding head (3). The control unit is electrically connected to the micro-column electromagnet array (3.1). The control unit is configured to: acquire the local curvature information of the irregular curved surface workpiece (24), and adaptively adjust the excitation current of each column electromagnet (327) in the micro-column electromagnet array (3.1) according to the local curvature information, so that the micro-column electromagnet array (3.1) generates a non-uniform magnetic field that matches the local curvature information, so as to adsorb the magnetic abrasive particles (4) on the cathode surface of the electrolytic grinding head (3) to form a gradient distribution and fit the contour shape of the corresponding processing area.
7. The irregular curved surface localized adaptive powder mixing electrolytic processing device according to claim 6, characterized in that: The micro-column electromagnet array (3.1) includes multiple columnar electromagnets (327), which are arranged along the circumferential direction. Each columnar electromagnet (327) is fitted with a steel sleeve (326), and a sealing plug (328) is provided at the upper end of the steel sleeve (326). The columnar electromagnets (327), the steel sleeve (326) and the sealing plug (328) together constitute an electromagnet assembly, which is installed in the circumferential hole of the multi-hole plastic box (32) of the electrolytic grinding head (3).
8. The irregular curved surface localized adaptive powder mixing electrolytic processing device according to claim 7, characterized in that: The electrolytic grinding head (3) also includes a grinding head connector (30), a connector (31), a copper electrode (33), a conduit (37), and a sealing ring (38). The three-axis moving mechanism is a three-axis servo slide module composed of an X-axis servo slide (11), a Y-axis servo slide (12), and a Z-axis servo slide (13). The grinding head connector (30) is connected to the slider of the Z-axis servo slide (13), and a flow channel is opened inside the grinding head connector (30). The connector (31) is set on the grinding head connector (30) and is used to connect the mixed powder electrolyte output by the mixed powder electrolyte generating device. The multi-hole plastic box (32) is set at the end of the grinding head connector (30) and is equipped with the micro-column electromagnet array (3.1) inside. The electrode (33) is located at the end of the perforated plastic box (32) to form an electrolytic circuit with the irregular curved surface workpiece (24); the conduit (37) is located through the central axis of the perforated plastic box (32); the sealing ring (38) is pressed against the position where the flow channel and the conduit (37) are joined; the connector (31), the flow channel in the grinding head connector (30), and the conduit (37) are connected in sequence to form a flow channel for the mixed powder electrolyte in the electrolytic grinding head (3); the liquid outlet end of the conduit (37) passes through the copper electrode (33) to spray the mixed powder electrolyte into the processing area.
9. The irregular curved surface localized adaptive powder mixing electrolytic processing device according to claim 6, characterized in that: The special fixture (2) includes a fixture body (20), a positioning key (21), a positioning permanent magnet (22), a support plate (26), a support block (27), and a clamping screw (25). The positioning key (21) is located at the bottom of the fixture body (2) and is used to cooperate with the T-slot of the machine base (1) to achieve positioning in the Y direction. The positioning permanent magnet (22) is fixed to the positioning hole (16) of the machine base (1) by a first screw (23) and is used to cooperate with the fixture body (20) to achieve positioning in the X direction. The support plate (26) and the support block (27) are located on the fixture body (20) and are used to support the irregular curved surface workpiece (24). The clamping screw (25) is used to clamp and fix the irregular curved surface workpiece (24) on the fixture body (2). The machine base (1) is provided with a drainage slope (14) and a drainage hole (15).
10. The irregular curved surface localized adaptive powder mixing electrolytic processing device according to claim 6, characterized in that: The mixing electrolyte generating device includes an electrolyte generating pipeline (a) and a slurry generating pipeline (b) both connected to the mixing chamber (9) at their ends. The mixing chamber (9) is connected to the connector (31) through an output pipeline (c). The electrolyte generation pipeline (a) is sequentially equipped with a first water pump (91), a first check valve (92), a gas-liquid booster pump (93), a second check valve (94), an accumulator (95), a first pressure gauge (96), a pressure regulating valve (97), and a second pressure gauge (98). The air inlet of the gas-liquid booster pump (93) is connected to an air compressor air source (99). A mixing agitator (9.3) and a flow control valve (9.4) are sequentially installed on the slurry generation pipeline (b). The starting end of the slurry generation pipeline (b) is connected to a second water pump (9.1) and a magnetic abrasive source (9.2). The mixing agitator (9.3) is used to mix magnetic abrasive particles with water to form a mixed slurry. The gas-liquid booster pump (93) and accumulator (95) are used to generate an electrolyte with a preset pressure. The mixing chamber (9) is used to mix the mixed slurry with the electrolyte to form a mixed powder electrolyte.