Electrical discharge flexible machining device and method based on programmable matrix magnetic field
By using a programmable matrix magnetic field and electromagnet units to form a magnetic powder protrusion structure in an electrical discharge machining (EDM) device, the problems of flexibility and efficiency in complex pattern processing are solved, and stable processing without the need for special electrode preparation and parameter adjustment is achieved, thus improving processing efficiency and stability.
Patent Information
- Application Number
- CN202611471669.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-21
- Publication Date
- 2026-11-03
AI Technical Summary
Existing electrical discharge machining technology struggles to balance flexibility and efficiency in machining complex patterns. The copying of forming electrodes requires cumbersome preparation of dedicated electrodes, and the parameter adjustment of CNC electrical discharge milling is complex and unstable.
The flexible EDM device employs a programmable matrix magnetic field. By arranging electromagnet units in an array inside the electrode shell and using an excitation controller to independently control the magnetic field to form a magnetic powder protrusion structure, a flexible discharge auxiliary electrode is achieved. Combined with servo gap control and working fluid flushing, stable spark discharge is realized.
It eliminates the need for specialized molding electrodes, offers high processing flexibility, efficiency, stability, and low electrode wear, and adapts to rapid production changes across multiple product categories, avoiding the cumbersome process of traditional electrode preparation and parameter adjustment.
Smart Images
Figure CN123024945A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrical discharge machining technology, specifically to a flexible electrical discharge machining device and method based on a programmable matrix magnetic field. Background Technology
[0002] Electrical discharge machining (EDM) is a non-contact, precision machining process applicable to any conductive metal material. It is now widely used in the manufacturing of difficult-to-cut alloys for aerospace applications, precision molds, and micro-shaped conductive components. The core etching mechanism of this process is as follows: the tool electrode and workpiece are connected to the positive and negative terminals of a pulse power supply, respectively. An insulating working fluid is filled between the electrodes, and the fluid can be supplied using either overall workpiece immersion or directional spraying. A servo-controlled closed-loop system drives the tool electrode to continuously feed a small amount towards the workpiece. When the gap between the electrodes shrinks to the critical discharge distance, the high-voltage pulse breaks down the insulating working fluid, forming a periodic pulsed spark discharge channel. A single discharge generates an instantaneous high temperature of 8000–20000℃, causing the surface metal of the workpiece at the discharge point to rapidly melt and vaporize. Molten metal fragments are detached from the machining area by the high-speed scouring action of the circulating working fluid. Numerous micron-sized etch pits formed by these single discharges continuously accumulate, ultimately replicating the target's three-dimensional geometric shape that matches the electrode or CNC trajectory. This machining method has no macroscopic mechanical cutting force and is not limited by tool hardness, but it has technical shortcomings in complex shape machining scenarios.
[0003] Currently, there are two main methods for achieving complex pattern EDM machining: one is the forming electrode copying EDM forming process, and the other is the CNC EDM milling process. Both have inherent drawbacks in that they are difficult to balance flexibility, machining efficiency, and process stability. Their specific working principles and shortcomings are as follows: 1. In the electrode copy-based EDM process, a dedicated forming electrode is prepared separately based on the workpiece's target machining profile drawing, perfectly matching its shape and contour. After clamping and calibrating the forming electrode, the corresponding complex structure is formed on the workpiece surface in one step by replicating the overall contour of the electrode. The above process suffers from a core problem: it is difficult to adapt to modern flexible manufacturing systems. Each irregularly shaped workpiece requires independent mold making, milling, and polishing to prepare a dedicated forming electrode, resulting in complex electrode processing steps and a lengthy preparation cycle. The cost of remanufacturing copper, graphite, and other electrode consumables is high after wear and tear. Furthermore, in situations involving multiple varieties, small batches, and rapid production changeovers, electrode replacement and secondary clamping and calibration account for a significant portion of the time, leading to insufficient overall production line response speed and extremely poor processing flexibility.
[0004] 2. In CNC electrical discharge milling, a simple cylindrical standard rod electrode is used. Relying on the machine tool's CNC system to preset three-axis / multi-axis motion trajectories, the workpiece material is quantitatively removed by scanning the electrode, and the material is superimposed to form the complex target shape. The above process, which relies on scanning trajectories to remove material, has a low material removal rate. The real-time machining status (workpiece surface curvature, tool wear, and chip removal conditions) changes in real time with the CNC trajectory. Different machining sections have vastly different requirements for process parameters such as pulse width, peak current, flushing fluid pressure, and flushing fluid flow rate, making parameter matching and debugging processes cumbersome. During variable trajectory machining, the discharge state is prone to arcing and short-circuiting anomalies, resulting in poor process stability and difficulty in ensuring the dimensional consistency of batch machining. Summary of the Invention
[0005] The purpose of this invention is to overcome the above-mentioned problems and provide a flexible electrical discharge machining device based on a programmable matrix magnetic field. This device can effectively balance the flexibility, efficiency and stability of electrical discharge machining of complex patterns, without the need to prepare a special forming electrode.
[0006] Another objective of this invention is to provide a flexible electrical discharge machining method based on a programmable matrix magnetic field.
[0007] The objective of this invention is achieved through the following technical solution: A flexible electrical discharge machining (EDM) device based on a programmable matrix magnetic field includes an electrode, a working fluid tank, and an excitation controller. The electrode includes an electrode shell and multiple electromagnet units arranged in an array inside the electrode shell. The working fluid tank stores a working fluid, and the electrode is located in the working fluid tank. The working fluid is an insulating working fluid containing magnetic powder. The excitation controller is used to independently control the conduction and excitation or demagnetization of each electromagnet unit. The excitation controller controls the electromagnet unit at a specified position inside the electrode shell to conduct excitation according to the target shape machining program.
[0008] The working principle of the above-mentioned flexible electrical discharge machining device based on a programmable matrix magnetic field is as follows: The workpiece to be processed is clamped and connected to the positive terminal of the pulse power supply, while the electrode is connected to the negative terminal. A pre-mixed insulating working fluid containing magnetic powder is added to the working fluid tank. The electrode and workpiece are positioned within the working fluid tank, with the gap between them filled with the working fluid. The operator inputs the target shape processing program into an external excitation controller. Based on the target shape processing program, the excitation controller controls the electromagnet unit at a designated position inside the electrode housing to conduct and excite, while the other electromagnet units remain de-energized and demagnetized. The energized electromagnet unit generates a directional and controllable magnetic field, causing the dispersed magnetic powder to directionally accumulate within the magnetic gap. The lower end face of the electrode shell forms a magnetic powder protrusion structure corresponding to the target shape. This magnetic powder protrusion structure serves as a flexible discharge auxiliary electrode. A servo gap control system drives the electrode to feed towards the workpiece at a constant speed, continuously reducing the gap between the two electrodes. The magnetic powder protrusion structure is the lowest position of the electrode, forming the smallest discharge gap across the entire range with the workpiece. When the smallest discharge gap reaches the appropriate discharge range for electric sparks (generally 10–50 μm), the inter-electrode pulse high voltage breaks down the insulating working fluid containing magnetic powder, generating a stable pulsed spark discharge between the magnetic powder protrusion structure and the workpiece. The discharge instantaneously generates a high temperature of 8000–20000℃, causing the surface metal of the workpiece to... Rapid melting and vaporization, coupled with the instantaneous explosive force of the discharge, strips away the molten metal, generating a mixture of solid and liquid electro-erosion products. A flushing unit in the working fluid tank directs the working fluid across the discharge gap, rapidly removing the generated metal electro-erosion products from the discharge area. The flowing working fluid simultaneously cools the discharge channel, neutralizing residual charges between electrodes, completing the deionization of the medium, avoiding continuous arc discharge and short circuits between electrodes, and ensuring the normal operation of the next pulse discharge. Maintaining constant array excitation mode, pulse electrical parameters, and flushing parameters, the magnetic powder protrusions continuously and precisely erode the workpiece material with sparks. After multiple discharges and the accumulation of micro-erosion pits, a layer of material is formed on the workpiece surface. The target shape is formed and the excitation contour is consistent; the processing depth data is collected in real time. After the processing shape and processing depth reach the preset process indicators, the excitation controller cuts off the excitation current of all electromagnet units, the pulse power supply stops outputting high voltage pulses, and terminates the inter-electrode discharge; the servo gap control system drives the electrode to return to the safe initial position and shuts off the working fluid circulation flushing; after the formed workpiece is disassembled, only the magnetic field conduction program (target shape processing program) inside the excitation controller needs to be changed to reconstruct a brand-new magnetic powder protrusion structure contour, and the next workpiece with different complex shapes can be directly processed to complete the flexible production changeover operation of multiple types of workpieces.
[0009] In a preferred embodiment of the present invention, each electromagnet unit is connected to the excitation controller via an independent control line. Through independent wiring, the excitation of each electromagnet unit can be individually switched on and off, enabling programmable and independent control of the magnetic field at a single point. Magnetic powder is gathered in situ using electromagnetic attraction, thereby flexibly altering the contour of the magnetic powder protrusion structure. The temporary magnetic powder protrusion structure serves as the electrode for electrical discharge machining (EDM) to complete the etching process.
[0010] Preferably, the device also includes a pulse power supply, which is connected to the electrode and the workpiece. By connecting the pulse power supply, during processing, the high voltage pulse between the electrodes breaks down the working fluid, and a stable pulsed spark discharge is generated between the magnetic powder protrusion structure and the workpiece, causing the surface metal of the workpiece to melt and vaporize rapidly, thereby achieving processing.
[0011] Preferably, the working fluid tank is a closed-loop circulating working fluid tank, and the closed-loop circulating working fluid tank is equipped with a flushing unit, which drives the insulating working fluid mixed with magnetic powder to directionally flush the discharge gap.
[0012] Preferably, the system further includes a servo gap control system, which drives the electrode to move. During machining, the servo gap control system drives the electrode to feed towards the workpiece; after machining is completed, the servo gap control system drives the electrode to return to a safe initial position.
[0013] A flexible electrical discharge machining method based on a programmable matrix magnetic field includes the following steps: (1) Workpiece clamping and pretreatment: The workpiece to be processed is clamped and fixed using a positioning clamping fixture. An insulating working fluid containing magnetic powder and prepared according to the specified ratio is added to the working fluid tank to ensure that the gap between the electrode and the workpiece is completely submerged in the working fluid. (2) Programmable magnetic field control to construct a flexible discharge magnetic powder protrusion structure: The operator enters the target shape processing program into the excitation controller. According to the target shape processing program, the excitation controller controls the electromagnet unit at a designated position inside the electrode shell to conduct excitation, while the other electromagnet units remain de-energized and demagnetized. The electromagnet unit that conducts excitation generates a directional and controllable magnetic field, and the magnetic powder dispersed in the magnetic gaps directionally gathers, forming a magnetic powder protrusion structure corresponding to the target shape on the lower end face of the electrode shell. This magnetic powder protrusion structure is a flexible discharge auxiliary electrode. (3) Control the electrode feed and trigger the controllable spark discharge at a fixed point: The servo gap control system drives the electrode to feed towards the workpiece. When the discharge gap between the magnetic powder protrusion structure and the workpiece reaches the appropriate discharge range of the electric spark, the pulse high voltage between the magnetic powder protrusion structure and the workpiece breaks down the insulating working fluid containing magnetic powder, and a stable pulse spark discharge is generated between the magnetic powder protrusion structure and the workpiece to process the surface of the workpiece. (4) The working fluid flushes the discharge gap to maintain continuous processing conditions: The flushing unit drives the working fluid to directionally flush the discharge gap, removing the metal electro-erosion products generated by the discharge from the discharge area. The flowing working fluid neutralizes the residual charge between the magnetic powder protrusion structure and the workpiece, completing the deionization of the medium. The magnetic powder protrusion structure continues to process the workpiece. (5) Continuous electrical discharge molding to complete the processing of the target shape: The micro-etched pits formed by multiple discharges overlap each other, forming a target shape on the workpiece surface that is consistent with the excitation profile. The processing depth data is collected in real time. After the processing morphology and processing depth reach the preset process parameters, the excitation controller cuts off the excitation current of all electromagnet units, the pulse power supply stops outputting high voltage pulses, and the pulse power supply discharge is terminated. (6) The servo gap control system drives the electrode back to the safe initial position and shuts off the working fluid circulation flushing; after disassembling the completed workpiece, it is only necessary to change the target shape processing program inside the excitation controller to reconstruct a brand-new magnetic powder protrusion structure outline and directly carry out the next workpiece processing of different shapes.
[0014] Compared with the prior art, the present invention has the following advantages: 1. The flexible EDM device based on a programmable matrix magnetic field in this invention integrates multiple arrayed electromagnet units inside the electrode shell. Each electromagnet unit is independently controlled and can be individually switched on and off, realizing programmable independent control of the magnetic field at a single point. During processing, only the magnetic field conduction program inside the excitation controller needs to be changed. It has strong processing flexibility and can realize the processing of complex shapes and complete flexible production changeover of multiple types of workpieces. There is no need to prepare special forming electrodes. The magnetic powder can be magnetically attracted and the discharge shape can be reconstructed by relying on the programming control of the electromagnet unit. There is no need for parameter matching and debugging, reprogramming of trajectory, etc. It can form the corresponding complex structure on the workpiece surface in one go, with fast processing efficiency and strong processing stability.
[0015] 2. The flexible EDM device based on a programmable matrix magnetic field in this invention has the advantages of extremely low electrode loss and low material cost. It dynamically adsorbs magnetic powder through a magnetic field to form a magnetic powder protrusion structure. The electrode shell does not directly participate in the spark discharge. The loss only occurs in the replenishable magnetic powder protrusion structure. The discharge loss can be automatically restored by the magnetic powder through the magnetic field, realizing theoretical non-destructive processing of the substrate electrode. This is different from the traditional processing method of irreversible discharge loss of copper and graphite solid electrodes, which requires frequent replacement and grinding. Attached Figure Description
[0016] Figure 1 This is a three-dimensional structural diagram of the electrode in the electrical discharge flexible processing device of the present invention.
[0017] Figure 2 This is a magnified schematic diagram of a partial structure of the electrode in this invention.
[0018] Figure 3 This is a three-dimensional structural diagram of a single electromagnet unit in the present invention when it is in operation.
[0019] Figure 4 This is a three-dimensional structural diagram of the electrode and workpiece in this invention.
[0020] Figure 5This is a schematic diagram of the structure of the electrical discharge machining (EDM) flexible processing device of the present invention. Detailed Implementation
[0021] To enable those skilled in the art to fully understand the technical solutions of the present invention, the present invention will be further described below in conjunction with embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.
[0022] See Figures 1-5 This addresses the problems of high cost, long preparation cycle, and poor processing flexibility in custom electrode EDM, as well as low material removal efficiency, cumbersome process parameter debugging, easy short circuit and arc initiation in variable trajectory discharge, and poor consistency in batch processing in CNC EDM. This embodiment discloses an electrical discharge machining (EDM) device based on a programmable matrix magnetic field. This device can process complex patterns and includes an electrode, a working fluid tank 8, and an excitation controller. The electrode includes an electrode housing 1 and multiple electromagnet units 2, which are arranged in an array inside the electrode housing 1. The working fluid tank 8 stores a working fluid 7, and the electrode is located in the working fluid tank 8. The working fluid 7 is an insulating working fluid containing magnetic powder. The excitation controller is used to independently control the conduction and excitation or demagnetization of each electromagnet unit 2. According to the target shape processing program, the excitation controller controls the electromagnet unit 2 at a specified position inside the electrode housing 1 to conduct and excite. The conducted and excited electromagnet unit 2 generates a directional controllable magnetic field, and the magnetic powder dispersed in the magnetic attraction gap is directionally aggregated, forming a magnetic powder protrusion structure 9 corresponding to the target shape on the lower end face of the electrode housing 1.
[0023] See Figures 1-5 In this embodiment, an array of electromagnet units 2 is arranged to form a matrix magnetic field that can be independently programmed and controlled. This enables dynamic processing of the discharge gap in zones, eliminating the need to prepare special-shaped electrodes. The magnetic field state between electrodes can be controlled according to the complex pattern contour as needed. This not only eliminates the electrode preparation and calibration process and improves the flexibility of processing and production changeover, but also optimizes the chip removal effect between electrodes and regulates the discharge channel by relying on the Lorentz force, suppresses abnormal discharge phenomena, simplifies the difficulty of debugging process parameters across the entire domain, and effectively balances the flexibility, efficiency and processing stability of EDM for complex patterns.
[0024] See Figures 1-5 The multiple electromagnet units 2 are arranged in a rectangular array inside the electrode shell 1, that is, the multiple electromagnet units are arranged in a regular row and column.
[0025] See Figures 1-5Each electromagnet unit 2 is connected to the excitation controller via an independent control line. Through independent wiring, the excitation of the electromagnet unit 2 can be turned on and off individually, realizing programmable and independent control of the magnetic field at a single point. Magnetic powder is gathered in situ by electromagnetic attraction, thereby flexibly changing the contour of the magnetic powder protrusion structure 9; the temporary magnetic powder protrusion structure 9 is used as an electrode for electrical discharge machining to complete the etching process.
[0026] See Figures 1-5 The flexible electrical discharge machining device in this embodiment also includes a pulse power supply 3, which connects the electrode and the workpiece 5. By connecting the pulse power supply 3, during machining, the high voltage pulse between the electrodes breaks down the working fluid 7, and a stable pulse spark discharge is generated between the magnetic powder protrusion structure 9 and the workpiece 5, causing the surface metal of the workpiece 5 to melt and vaporize rapidly, thereby achieving machining.
[0027] See Figures 1-5 The positive terminal of the pulse power supply 3 is connected to the workpiece 5, and the negative terminal of the pulse power supply 3 is connected to the electrode, specifically the electrode housing 1; in other embodiments, the positive terminal of the pulse power supply 3 may be connected to the electrode, and the negative terminal to the workpiece 5.
[0028] See Figures 1-5 The working fluid tank 8 is a closed-loop circulating working fluid tank, which is equipped with a flushing unit. The flushing unit drives the insulating working fluid mixed with magnetic powder to directionally flush the discharge gap.
[0029] See Figures 1-5 The flexible electrical discharge machining apparatus in this embodiment also includes a servo gap control system, which drives the electrode to move. During machining, the servo gap control system drives the electrode to feed towards the workpiece 5. After machining is completed, the servo gap control system drives the electrode to return to the safe initial position.
[0030] See Figures 1-5 The working principle of the above-mentioned flexible electrical discharge machining device based on a programmable matrix magnetic field is as follows: The workpiece 5 to be processed is locked and fixed using a positioning clamping fixture. The level of the workpiece 5 and the processing position are adjusted. The workpiece 5 is connected to the positive terminal of the pulse power supply 3, and the electrode is connected to the negative terminal of the pulse power supply 3. After confirming that the positive and negative terminals of the pulse power supply 3 are connected correctly, insulating working fluid containing magnetic powder and prepared according to the specified ratio is added to the working fluid tank 8. The electrode and the workpiece 5 are in the working fluid tank 8, and the gap between the electrode and the workpiece 5 is filled with working fluid 7 and completely submerged in working fluid 7. The operator enters the target shape processing program into the external excitation controller. According to the target shape processing program, the excitation controller controls the electromagnet unit 2 at the designated position inside the electrode housing 1 to conduct and excite, while the other electromagnet units 2 remain de-energized and demagnetized. The electromagnet unit 2 at the designated position is energized. Afterwards, the resulting excitation profile is identical to the target shape; for example, if the target shape is set as an "I" shaped profile in the target shape processing program, the electromagnet unit 2 that conducts the excitation will also form a corresponding "I" shape, forming an "I" shaped conducting area 4, and the excitation profile is also "I" shaped. The electromagnet unit 2 that conducts the excitation generates a directional controllable magnetic field, and the magnetic powder dispersed in the magnetic gap directionally accumulates, forming a magnetic powder protrusion structure 9 corresponding to the target shape on the lower end face of the electrode shell 1. This magnetic powder protrusion structure 9 is a flexible discharge auxiliary electrode, and the outline of the magnetic powder protrusion structure 9 is "I" shaped; the shape of the flexible discharge auxiliary electrode changes according to the target shape processing program and has an arbitrarily reconfigurable function; the servo gap control system drives the electrode to feed towards the workpiece 5 at a uniform speed, and the two The electrode gap continuously decreases; the magnetic powder protrusion structure 9 is the lowest position of the electrode, forming the smallest discharge gap across the entire area with the workpiece 5. When the smallest discharge gap reaches the appropriate discharge range for electric sparks (generally 10-50 μm), the high voltage pulse between the electrodes breaks down the insulating working fluid containing magnetic powder, and a stable pulse spark discharge is generated between the magnetic powder protrusion structure 9 and the workpiece 5; the discharge instant generates a high temperature of 8000-20000℃, causing the surface metal of the workpiece 5 to melt and vaporize rapidly. At the same time, the instantaneous explosive force of the discharge strips away the molten metal, generating a mixture of solid and liquid electro-erosion products; the closed-loop circulating working fluid tank is equipped with a flushing unit that drives the working fluid 7 to directionally flush the discharge gap, quickly removing the metal electro-erosion products generated by the discharge from the discharge area; the flowing working fluid 7 synchronously cools the discharge channel. The process involves neutralizing residual charges between electrodes, deionizing the medium, preventing continuous arc discharge and short circuits between electrodes, and ensuring the normal operation of the next pulse discharge. It maintains constant array excitation morphology, pulse electrical parameters, and flushing fluid parameters. The magnetic powder protrusion structure 9 continuously and precisely erodes the material of workpiece 5 using sparks. After multiple discharge micro-etching pits are superimposed, a target shape consistent with the excitation contour is formed on the surface of workpiece 5, and an "I"-shaped slot 6 is machined into workpiece 5. Real-time acquisition of machining depth data is performed. Once the machining morphology and depth reach the preset process parameters, the excitation controller cuts off the excitation current of all electromagnet units 2, the pulse power supply 3 stops outputting high-voltage pulses, and the inter-electrode discharge is terminated. The servo gap control system drives the electrodes back to the safe initial position and shuts off the working fluid 7 circulation flushing.After disassembling and molding the workpiece 5, only the internal magnetic field conduction program of the excitation controller (target shape machining program) needs to be modified to reconstruct the contour of the new magnetic powder protrusion structure 9, and directly carry out the machining of the next workpiece 5 with different complex shapes, thus completing the flexible production changeover operation of multiple types of workpieces 5.
[0031] See Figures 1-5 This embodiment also discloses a flexible electrical discharge machining method based on a programmable matrix magnetic field, including the following steps: (1) Clamping and pretreatment of workpiece 5: The workpiece 5 to be processed is clamped and fixed by a positioning clamping fixture. The working liquid tank 8 is filled with a properly prepared insulating working liquid containing magnetic powder to ensure that the gap between the electrode and the workpiece 5 is completely submerged in the working liquid 7. (2) Programmable magnetic field control to construct a flexible discharge magnetic powder protrusion structure 9: The operator enters the target shape processing program into the excitation controller. According to the target shape processing program, the excitation controller controls the electromagnet unit 2 at a designated position inside the electrode shell 1 to conduct excitation, while the other electromagnet units 2 remain de-energized and demagnetized. The electromagnet unit 2 that conducts excitation generates a directional controllable magnetic field, and the magnetic powder dispersed in the magnetic attraction gap directionally gathers, forming a magnetic powder protrusion structure 9 corresponding to the target shape on the lower end face of the electrode shell 1. This magnetic powder protrusion structure 9 is a flexible discharge auxiliary electrode. (3) Control the electrode feed and trigger the controllable spark discharge at a fixed point: The servo gap control system drives the electrode to feed towards the workpiece 5. When the discharge gap between the magnetic powder protrusion structure 9 and the workpiece 5 reaches the appropriate discharge range of the electric spark, the pulse high voltage between the magnetic powder protrusion structure 9 and the workpiece 5 breaks down the insulating working fluid containing magnetic powder, and a stable pulse spark discharge is generated between the magnetic powder protrusion structure 9 and the workpiece 5 to process the surface of the workpiece 5; the appropriate discharge range of the electric spark is 10 to 50 μm. (4) Working fluid 7 flushes the discharge gap to maintain continuous processing conditions: The flushing unit drives the working fluid 7 to directionally flush the discharge gap, removing the metal electro-erosion products generated by the discharge from the discharge area. The flowing working fluid 7 neutralizes the residual charge between the magnetic powder protrusion structure 9 and the workpiece 5, completing the deionization of the medium. The magnetic powder protrusion structure 9 continues to process the workpiece 5. (5) Continuous electrical discharge molding to complete the processing of the target shape: The micro-etching pits formed by multiple discharges overlap each other, forming a target shape on the surface of workpiece 5 that is consistent with the excitation contour. The processing depth data is collected in real time. After the processing morphology and processing depth reach the preset process parameters, the excitation controller cuts off the excitation current of all electromagnet units 2, and the pulse power supply 3 stops outputting high voltage pulses, terminating the discharge of the pulse power supply 3. (6) The servo gap control system drives the electrode back to the safe initial position and shuts off the working fluid 7 circulation flushing; disassemble the completed workpiece 5, only need to change the target shape processing program inside the excitation controller, and reconstruct the new magnetic powder protrusion structure 9 contour, and directly carry out the processing of the next workpiece 5 with different shapes.
[0032] See Figures 1-5 In this embodiment, the electrode is a rectangular, independently controllable, programmable matrix magnetic field electrode structure. Multiple arrayed electromagnet units 2 are integrated inside the electrode shell 1. Each electromagnet unit 2 is independently wired and can be individually switched on and off, achieving programmable and independent control of the magnetic field at a single point. The overall shape of the electrode is a fixed standard structure, eliminating the need for machining irregularly shaped electrodes. Furthermore, in an insulating working fluid environment containing magnetic powder, the conduction of some electromagnet units 2 is controlled by programming, utilizing electromagnetic attraction to gather magnetic powder in situ, forming a magnetic powder protrusion structure 9 with an arbitrarily changeable contour on the lower end face of the electrode shell 1. This temporarily formed magnetic powder protrusion structure 9 serves as a flexible discharge auxiliary electrode to complete the etching process. Existing technologies rely on the electrode's own solid structure as the discharge working surface, which cannot be changed in situ. This embodiment does not modify the electrode; instead, it relies on electromagnetically controlled powder to construct a temporary, reconfigurable discharge working surface, changing the electrode forming method of electrical discharge machining.
[0033] When machining complex, irregular shapes, the electrode installation position, electrode movement trajectory, basic electrical parameters, and flushing fluid parameters remain completely unchanged. Only the target shape machining program needs modification to switch machining morphologies. Magnetic field control adapts to different machining conditions, and the Lorentz force helps stabilize chip removal and discharge states between electrodes. A programmable matrix magnetic field continuously adsorbs magnetic powder suspended in the working fluid 7, constructing a magnetic powder-type temporary discharge working surface. During discharge machining, if the high temperature of the spark or the discharge impact causes surface magnetic powder loss, the matrix excitation magnetic field can continuously and directionally adsorb surrounding free magnetic powder, replenishing the lost powder in real time, dynamically restoring the discharge protrusion morphology, and continuously maintaining the integrity of the discharge working surface, theoretically achieving lossless electrode machining. In this embodiment, the electrode shell 1 does not directly participate in discharge loss; loss only occurs in the replenishable magnetic powder protrusion structure 9. After the magnetic powder protrusion structure 9 is damaged, it is automatically replenished and repaired by magnetic attraction, solving the problem of electrode loss in electrical discharge machining.
[0034] The above are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above content. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A flexible electrical discharge machining device based on a programmable matrix magnetic field, characterized in that, The device includes electrodes, a working fluid tank, and an excitation controller. The electrodes consist of an electrode housing and multiple electromagnet units arranged in an array inside the electrode housing. The working fluid tank stores a working fluid, and the electrodes are located within the working fluid tank. The working fluid is an insulating working fluid containing magnetic powder. The excitation controller is used to independently control the conduction and excitation or demagnetization of each electromagnet unit. The excitation controller controls the electromagnet units at designated positions inside the electrode housing to conduct excitation according to the target shape processing program.
2. The electrical discharge machining (EDM) flexible processing device based on a programmable matrix magnetic field according to claim 1, characterized in that, Each electromagnet unit is connected to the excitation controller via an independent control line.
3. The electrical discharge machining (EDM) flexible processing device based on a programmable matrix magnetic field according to claim 2, characterized in that, It also includes a pulse power supply, which is connected to the electrode and the workpiece.
4. The electrical discharge machining (EDM) flexible processing device based on a programmable matrix magnetic field according to claim 3, characterized in that, The working fluid tank is a closed-loop circulating working fluid tank, which is equipped with a flushing unit. The flushing unit drives the insulating working fluid mixed with magnetic powder to directionally flush the discharge gap.
5. The electrical discharge machining (EDM) flexible processing device based on a programmable matrix magnetic field according to claim 4, characterized in that, It also includes a servo gap control system, which is used to drive the electrode to move.
6. A flexible electrical discharge machining method based on a programmable matrix magnetic field, characterized in that, The flexible electrical discharge machining method, applied to the flexible electrical discharge machining apparatus as described in any one of claims 1-5, includes the following steps: (1) Workpiece clamping and pretreatment: The workpiece to be processed is clamped and fixed using a positioning clamping fixture. An insulating working fluid containing magnetic powder and prepared according to the specified ratio is added to the working fluid tank to ensure that the gap between the electrode and the workpiece is completely submerged in the working fluid. (2) Programmable magnetic field control to construct a flexible discharge magnetic powder protrusion structure: The operator enters the target shape processing program into the excitation controller. According to the target shape processing program, the excitation controller controls the electromagnet unit at a designated position inside the electrode shell to conduct excitation, while the other electromagnet units remain de-energized and demagnetized. The electromagnet unit that conducts excitation generates a directional and controllable magnetic field, and the magnetic powder dispersed in the magnetic gaps directionally gathers, forming a magnetic powder protrusion structure corresponding to the target shape on the lower end face of the electrode shell. This magnetic powder protrusion structure is a flexible discharge auxiliary electrode. (3) Control the electrode feed and trigger the controllable spark discharge at a fixed point: The servo gap control system drives the electrode to feed towards the workpiece. When the discharge gap between the magnetic powder protrusion structure and the workpiece reaches the appropriate discharge range of the electric spark, the pulse high voltage between the magnetic powder protrusion structure and the workpiece breaks down the insulating working fluid containing magnetic powder, and a stable pulse spark discharge is generated between the magnetic powder protrusion structure and the workpiece to process the surface of the workpiece. (4) The working fluid flushes the discharge gap to maintain continuous processing conditions: The flushing unit drives the working fluid to directionally flush the discharge gap, removing the metal electro-erosion products generated by the discharge from the discharge area. The flowing working fluid neutralizes the residual charge between the magnetic powder protrusion structure and the workpiece, completing the deionization of the medium. The magnetic powder protrusion structure continues to process the workpiece. (5) Continuous electrical discharge molding to complete the processing of the target shape: The micro-etched pits formed by multiple discharges overlap each other, forming a target shape on the workpiece surface that is consistent with the excitation profile. The processing depth data is collected in real time. After the processing morphology and processing depth reach the preset process parameters, the excitation controller cuts off the excitation current of all electromagnet units, the pulse power supply stops outputting high voltage pulses, and the pulse power supply discharge is terminated. (6) The servo gap control system drives the electrode back to the safe initial position and shuts off the working fluid circulation flushing; after disassembling the completed workpiece, it is only necessary to change the target shape processing program inside the excitation controller to reconstruct a brand-new magnetic powder protrusion structure outline and directly carry out the next workpiece processing of different shapes.