Electrochemical discharge additive and subtractive synergistic preparation method for inner wall of variable cross-section sampling needle tube

Abstract

The invention relates to the technical field of micromachining and surface engineering, and discloses a variable cross-section sampling needle tube inner wall electrochemical discharge additive and subtractive material synergistic preparation method which comprises the following steps: adsorbing magnetic nano powder to a magnet electrode handle to assemble a flexible tool electrode; the flexible tool electrode is inserted into a sampling needle tube injected with electrolyte containing silver nitrate and low-surface-energy substances, a local thermal field is generated through electrochemical discharge, and the flexible tool electrode is extruded in a reducing area to force powder to be rearranged to actively adapt to pore diameter changes. According to the method, the micro-nano nested structure is etched through electrochemical discharge, the recast layer is removed through mechanical grinding of adsorbed magnetic nano powder, antibacterial particles and low-surface-energy substances are induced to be co-deposited in situ through a discharge thermal field, and the silver antibacterial coating is formed in the micro-nano nested structure. The integrated cooperation of variable cross-section deep hole inner wall material removal, surface finishing and functional coating preparation is realized, and the inner wall of the sampling needle tube is endowed with hydrophobic and antibacterial properties.

Description

Technical Field

[0001] This invention relates to the field of microfabrication and surface engineering technology, specifically to a method for the synergistic preparation of electrochemical discharge additives and subtractives on the inner wall of a variable cross-section sampling needle. Background Technology

[0002] As a key component for fluid aspiration and distribution, the properties of the inner wall surface of medical sampling needles directly affect the accuracy of micro-liquid transfer and biosafety. Residual liquid on the inner wall can lead to cross-contamination of samples, bacterial growth, and infection risks.

[0003] To meet the requirements of fluid dynamics, existing micro-sampling needles are often designed with a tapered variable cross-section shape for the inner hole. Traditional deep hole machining often uses rigid sizing electrodes with fixed dimensions, which cannot actively adapt to the characteristic of continuous axial variation of the inner hole diameter. When machining the variable cross-section area, the rigid electrode is prone to rigid interference with the inner wall, which can lead to device damage, or the machining failure can be caused by excessive distance between electrodes.

[0004] In addition, existing functional coating preparation usually involves separate steps of substrate surface texturing, polishing and coating deposition, which leads to a longer manufacturing cycle. Directly depositing coatings on smooth inner walls that have not undergone micro-nano structure treatment mainly relies on physical adsorption and lacks mechanical interlocking effect, making them easy to peel off when subjected to high-speed fluid scouring. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for the synergistic preparation of electrochemical discharge additive and subtractive materials on the inner wall of a variable cross-section sampling needle. This method solves the problems of existing rigid fixed-sizing electrodes being unable to actively adapt to the variable cross-section shape of the sampling needle's inner hole, leading to processing failures or interference damage, as well as the problems of existing functional coating preparation processes being fragmented and coatings deposited on smooth surfaces lacking mechanical interlocking effects, resulting in weak adhesion and easy peeling.

[0006] To achieve the above objectives, the first aspect of the present invention provides a method for the synergistic preparation of electrochemical discharge additives and subtractives on the inner wall of a variable cross-section sampling needle, comprising the following steps: The sampling needle is fixed in the electrolyte tank fixture, and an electrolyte containing silver nitrate solution and low surface energy material is injected. Magnetic nanoparticles are adsorbed onto the surface of the magnetic electrode handle to assemble a flexible tool electrode.

[0007] The XYZ three-axis motion platform is driven to insert the flexible tool electrode into the inner hole of the sampling needle tube. The rotating spindle drives the flexible tool electrode to rotate and feed linearly along the Z-axis. The flexible tool electrode forms a spiral scanning trajectory relative to the inner wall of the sampling needle tube.

[0008] When the adjustable pulse power supply is turned on, the flexible tool electrode acts as the cathode, and hydrogen bubbles coalesce to form a gaseous thin film. The gaseous thin film undergoes electrical breakdown to establish an electrochemical discharge channel.

[0009] The flexible tool electrode enters the diameter-changing region of the sampling needle tube. A rigid mechanical extrusion force is applied to the inner wall of the sampling needle tube, forcing the magnetic nanopowder to overcome the magnetic dipole force and slide radially inward, causing a rearrangement of its position. The diameter of the flexible tool electrode decreases to adapt to the change in the cross-section of the inner hole of the sampling needle tube. The magnetic field force of the magnetic electrode handle provides a radial restoring force to keep the magnetic nanopowder tightly attached to the inner wall of the sampling needle tube. The electrochemical discharge releases pulse energy to melt the metal substrate on the inner wall of the sampling needle tube and etch the micro-nano nested structure. The magnetic nanopowder acts as a micro abrasive to mechanically grind the inner wall of the sampling needle tube to remove the recast layer. The local thermal field of the electrochemical discharge induces the decomposition of silver nitrate to release antibacterial particles. The antibacterial particles are mixed with low surface energy materials and deposited on the surface and pores of the micro-nano nested structure to form a silver antibacterial coating.

[0010] The flexible tool electrode is detached from the sampling needle tube, the sampling needle tube is cleaned and dried to cure the silver antibacterial coating, resulting in a variable cross-section sampling needle tube with hydrophobic and antibacterial functions.

[0011] A second aspect of the present invention provides a variable cross-section sampling needle inner wall electrochemical discharge additive and subtractive material co-processing device, including a processing platform base, an XYZ three-axis motion platform, an electrolyte tank, a rotary spindle, and an adjustable pulse power supply.

[0012] The processing platform base is connected to the XYZ three-axis motion platform. The XYZ three-axis motion platform is equipped with an electrolyte tank. The electrolyte tank contains a clamp for holding the sampling needle tube. The processing platform base is equipped with a rotating spindle. The lower end of the rotating spindle holds a magnetic electrode handle through an electrode chuck. The magnetic electrode handle is made of conductive ferromagnetic material or conductive material with embedded permanent magnets and adsorbs magnetic nanoparticles to form a flexible tool electrode.

[0013] The positive terminal of the adjustable pulse power supply is connected to the auxiliary electrode placed inside the electrolyte tank, and the negative terminal is connected to the electric bearing sleeved on the outside of the rotating spindle. The electric bearing realizes the current transmission between the stationary wire and the rotating spindle. The current is transmitted to the magnetic nanoparticles through the rotating spindle, electrode chuck and magnetic electrode handle, so that the flexible tool electrode constitutes the cathode of the electrochemical reaction. The electrolyte tank is connected to the electrolyte circulation system to maintain the closed-loop flow of the electrolyte.

[0014] This invention provides a method for the synergistic preparation of additive and subtractive materials through electrochemical discharge on the inner wall of a variable cross-section sampling needle. It possesses the following beneficial effects: 1. This invention uses a magnetic electrode handle to adsorb magnetic nanoparticles to form a flexible tool electrode. Extrusion force is applied to the inner wall of the variable diameter area of ​​the sampling needle tube to force the magnetic nanoparticles to rearrange radially. The flexible tool electrode actively adapts to the change of the inner hole cross-section, and the magnetic field force keeps the magnetic nanoparticles tightly attached to the inner wall of the sampling needle tube, thereby realizing continuous processing of the inner hole surface with variable cross-section.

[0015] 2. This invention provides physical anchoring points through the micro-nano nested structure formed by electrochemical discharge etching, optimizes surface quality by removing the recast layer with magnetic nanopowder through mechanical grinding, and embeds a silver antibacterial coating inside the micro-nano nested structure. The synergistic effect of adding and subtracting materials utilizes the mechanical interlocking effect to enhance the bonding strength between the silver antibacterial coating and the substrate on the inner wall of the sampling needle.

[0016] 3. This invention utilizes the local thermal field of electrochemical discharge to induce the in-situ decomposition of silver nitrate solution and the deposition of low surface energy materials. Antibacterial particles and low surface energy materials fill the micro-nano nested structure, achieving simultaneous material removal and functional layer construction, thus endowing the inner wall of the sampling needle with both hydrophobic and antibacterial functions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the device structure of the present invention; Figure 2 This is a schematic diagram of the inner wall principle of the variable cross-section sampling needle of the present invention; Figure 3 This is a schematic diagram illustrating the principle of fabricating a functional surface for the flexible tool head of the present invention. Figure 4 This is a flowchart of the preparation method of the present invention.

[0018] The components include: 1. Adjustable pulse power supply; 2. Motion control system; 3. Electrolyte tank; 4. Auxiliary electrode; 5. XYZ three-axis motion platform; 6. Machining platform base; 7. Rotary spindle; 8. Spindle holder; 9. Electrostatic bearing; 10. Electrode chuck; 11. Magnetic electrode handle; 12. Magnetic nanopowder; 13. Sampling needle; 14. Fixture; 15. Electrolyte; 16. Electrolyte circulation system; 17. Oxygen bubble; 18. Hydrogen bubble; 19. Sampling needle diameter variation area; 20. Low surface energy material; 21. Electrochemical discharge; 22. Antibacterial particles; 23. Micro-nano nested structure; 24. Silver antibacterial coating. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] See attached document Figure 1-3 This invention provides an electrochemical discharge additive-subtractive material co-processing device for the inner wall of a variable cross-section sampling needle tube 13, used to prepare the functional surface of the inner wall of the variable cross-section sampling needle tube 13, including: a processing platform base 6, an XYZ three-axis motion platform 5, an electrolyte tank 3, and a rotating spindle 7.

[0021] The processing platform base 6 constitutes the basic load-bearing component of the electrochemical discharge additive and subtractive material co-processing device on the inner wall of the variable cross-section sampling needle tube 13. The processing platform base 6 provides rigid support. An XYZ three-axis motion platform 5 is mechanically connected to the upper surface of the processing platform base 6. The signal input terminal of the XYZ three-axis motion platform 5 is electrically connected to the motion control system 2. The motion control system 2 stores a motion control algorithm and sends pulse control signals to the XYZ three-axis motion platform 5. The XYZ three-axis motion platform 5 performs three-dimensional spatial coordinate positioning motion according to the pulse control signals.

[0022] An electrolyte tank 3 is mounted on the upper surface of the XYZ three-axis motion platform 5. The XYZ three-axis motion platform 5 drives the electrolyte tank 3 to perform displacement motion in the horizontal plane. The electrolyte tank 3 is made of corrosion-resistant and insulating material. A fluid interface is provided on the side wall of the electrolyte tank 3. The fluid interface pipeline is connected to the electrolyte circulation system 16. The electrolyte circulation system 16 includes a corrosion-resistant circulation pump and a filter device. The output end of the electrolyte circulation system 16 is connected to the inside of the electrolyte tank 3, and the input end of the electrolyte circulation system 16 is connected to the drain port of the electrolyte tank 3. The electrolyte circulation system 16 drives the electrolyte 15 to form a closed loop flow between the inside of the electrolyte tank 3 and the external pipeline. The electrolyte circulation system 16 maintains the temperature parameters and chemical composition concentration parameters of the electrolyte 15 constant.

[0023] A clamp 14 is mechanically fixed to the bottom surface of the electrolyte tank 3. The clamp 14 has a positioning slot and a locking mechanism. The clamp 14 is used to vertically clamp the sampling needle tube 13. After the sampling needle tube 13 is fixed by the clamp 14, the entire sampling needle tube 13 is completely immersed below the surface of the electrolyte 15 contained in the electrolyte tank 3. The electrolyte 15 fills the internal pores of the sampling needle tube 13, and a liquid phase contact interface is established between the electrolyte 15 and the inner wall surface of the sampling needle tube 13.

[0024] A Z-axis column is vertically installed on the side of the machining platform base 6. A spindle holder 8 is installed on the Z-axis column. A rotating spindle 7 is fixed in place by the internal hole of the spindle holder 8. The axis of the rotating spindle 7 is perpendicular to the XY horizontal plane. The motor control end of the rotating spindle 7 is electrically connected to the motion control system 2. The motion control system 2 adjusts the speed parameters and rotation direction of the rotating spindle 7. An electrode chuck 10 is mechanically connected to the lower output shaft of the rotating spindle 7. The lower end of the electrode chuck 10 coaxially holds a magnetic electrode handle 11. The magnetic electrode handle 11 is made of conductive ferromagnetic material or conductive material with embedded permanent magnets. A predetermined mass of magnetic nanopowder 12 is adsorbed around the magnetic electrode handle 11. The magnetic nanopowder 12 is arranged along the direction of the magnetic field line under the action of the magnetic field force of the magnetic electrode handle 11. The magnetic nanopowder 12 covers the outer surface of the magnetic electrode handle 11. The magnetic electrode handle 11 and the magnetic nanopowder 12 adsorbed on the surface of the magnetic electrode handle 11 physically combine to form a flexible tool electrode.

[0025] The device also includes an adjustable pulse power supply 1, which has a positive output terminal and a negative output terminal. The positive output terminal of the adjustable pulse power supply 1 is connected to an auxiliary electrode 4 via a wire. The auxiliary electrode 4 is physically placed inside the electrolyte tank 3 and immersed in the electrolyte 15. The auxiliary electrode 4 constitutes the anode of the electrochemical reaction. The negative output terminal of the adjustable pulse power supply 1 is connected to an electric bearing 9 via a wire. The electric bearing 9 is sleeved on the outside of the rotating shaft of the rotating spindle 7. The electric bearing 9 realizes the current transmission between the stationary wire and the rotating spindle 7. The current is transmitted to the electrode chuck 10 via the rotating spindle 7. The electrode chuck 10 transmits the current to the magnetic electrode handle 11. The magnetic electrode handle 11 transmits the current to the magnetic nanopowder 12. The flexible tool electrode constitutes the cathode of the electrochemical reaction.

[0026] The electrolyte 15 consists of a basic electrolyte, a silver nitrate solution, and a low surface energy substance 20. The silver nitrate solution provides the source of silver, and the low surface energy substance 20 provides the source of hydrophobic groups.

[0027] See attached document Figure 4 This invention provides a method for the synergistic preparation of electrochemical discharge additives and subtractives on the inner wall of a variable cross-section sampling needle, comprising the following steps: S1. Insert the sampling needle tube 13 to be processed vertically into the positioning hole of the clamp 14 inside the electrolyte tank 3 and lock it. Prepare the electrolyte 15: dissolve silver nitrate crystals in deionized water, add low surface energy substance 20 and mix evenly. Pour the mixed solution into the electrolyte tank 3. The liquid level should be higher than the top of the sampling needle tube 13. Start the electrolyte circulation system 16 to drive the electrolyte 15 to flow.

[0028] Insert the magnetic electrode handle 11 into the electrode chuck 10 at the end of the rotating spindle 7, weigh a specific mass of magnetic nanopowder 12 and place it within the magnetic field range of the magnetic electrode handle 11, use the magnetic force to capture the powder so that it forms a brush-like flexible structure on the surface of the electrode handle, assemble it into a flexible tool electrode, place the auxiliary electrode 4 in the electrolyte 15, connect the positive terminal of the adjustable pulse power supply 1 to the auxiliary electrode 4 and the negative terminal to the lead bearing 9, and check the integrity of the circuit connection.

[0029] S2. Run the positioning program of the motion control system 2, drive the XYZ three-axis motion platform 5 to move the electrolyte tank 3 and the sampling needle tube 13 in the XY plane until the central axis of the inner hole of the sampling needle tube 13 coincides with the rotation center axis of the flexible tool electrode. Then drive the platform to descend along the Z axis and insert the flexible tool electrode into the inner hole of the sampling needle tube 13 to the bottom predetermined starting processing point.

[0030] The rotating spindle 7 is started to drive the magnetic electrode handle 11 and the magnetic nanopowder 12 to rotate synchronously. At the same time, the motion control system 2 controls the platform to execute the Z-axis reciprocating linear feed. The rotational motion and the Z-axis linear feed motion are vector-combined to form a spiral scanning trajectory covering the entire surface of the inner wall of the sampling needle tube 13 relative to the flexible tool electrode.

[0031] S3. Turn on the adjustable pulse power supply 1 to output DC pulse voltage. Electrolyte 15 acts as a conductive medium to close the circuit. Oxidation reaction occurs on the surface of auxiliary electrode 4 to precipitate oxygen bubbles 17. Reduction reaction occurs on the surface of flexible tool electrode to precipitate hydrogen bubbles 18. Since the generation rate of hydrogen bubbles 18 is greater than the detachment rate, a large number of bubbles coalesce on the outer surface of tool electrode to form a continuous gas phase film, which physically isolates electrolyte 15.

[0032] The gas-phase thin film cuts off the ion conduction pathway, causing the resistance to rise sharply. The voltage drops in full along the thickness of the gas film, causing the electric field strength on the gas film to exceed the dielectric strength threshold. The gas-phase thin film undergoes electrical breakdown at the point of strongest electric field and triggers spark discharge, forming an electrochemical discharge channel 21 that connects the tip of the magnetic nanopowder 12 to the inner wall of the sampling needle tube 13.

[0033] S4. The flexible tool electrode enters the variable diameter region 19 of the sampling needle tube 13. The inner hole cross-section is reduced, which causes the inner wall to apply a rigid mechanical extrusion force to the magnetic nanopowder 12. The rigid mechanical extrusion force is greater than the magnetic dipole interaction force between the powders, which forces the powder to slide and rearrange radially inward. The diameter of the tool electrode is reduced accordingly to actively adapt to the change in the shape of the inner hole. The radial restoring force provided by the magnetic field ensures that the magnetic nanopowder 12 always adheres to the inner wall of the sampling needle tube 13 and maintains dynamic contact.

[0034] Electrochemical discharge 21 continuously releases instantaneous pulse energy, and the local high temperature causes the inner wall metal substrate to melt and vaporize. Combined with the electrolyte 15 to assist in corrosion etching, micro-pits are formed, which are superimposed to form a micro-nano nested structure 23 containing nanoscale pores, thereby increasing the specific surface area.

[0035] Meanwhile, the rotating magnetic nanopowder 12 acts as a micro abrasive under the normal pressure of the magnetic field, mechanically grinding the inner wall, removing the recast layer protrusions and oxide scale generated by the discharge, reducing the peak-valley difference of the micro-nano nested structure 23, and playing a micro-polishing role.

[0036] The discharge thermal field heats the electrolyte 15 in the micro-area, inducing the thermal decomposition of silver nitrate to release silver antibacterial particles 22, which are mixed and suspended with low surface energy material 20. They are deposited on the surface and pores of the molten micro-nano nested structure 23 by the impact of the fluid. After cooling and solidification, a silver antibacterial coating 24 is formed. The physical anchoring effect generated by the micro-nano structure enhances the coating adhesion. The low surface energy material 20 enriched on the surface gives the inner wall hydrophobic function, while the released silver ions give it antibacterial function.

[0037] S5, the motion control system 2 stops outputting signals and power, stops the spindle rotation, and the XYZ three-axis motion platform 5 drives the flexible tool electrode to retract upward along the Z-axis to disengage from the sampling needle tube 13, and releases the clamp 14 to remove the workpiece.

[0038] The sampling needle 13 is placed in an ultrasonic cleaning tank, and the residual electrolyte 13, loose powder and processing waste are removed by ultrasonic cavitation effect. After being taken out, it is blown away with clean compressed air to remove water, and then placed in a constant temperature drying oven to dry according to the set parameters. The silver antibacterial coating 24 is cured to obtain the finished product of the variable cross-section sampling needle 13 with hydrophobic and antibacterial functions.

Claims

1. A method for synergistic preparation of additive and subtractive materials through electrochemical discharge on the inner wall of a variable cross-section sampling needle, characterized in that, Includes the following steps: Insert the sampling needle (13) into the clamp (14) inside the electrolyte tank (3) and inject the electrolyte (15). The electrolyte (15) contains silver nitrate solution and low surface energy material (20). Adsorb the magnetic nanopowder (12) onto the surface of the magnetic electrode handle (11) to assemble a flexible tool electrode. Drive the XYZ three-axis motion platform (5) to insert the flexible tool electrode into the inner hole of the sampling needle tube (13), rotate the spindle (7) to drive the flexible tool electrode to rotate and feed linearly along the Z-axis to form a spiral scanning trajectory; When the adjustable pulse power supply (1) is turned on, hydrogen bubbles (18) are generated on the surface of the flexible tool electrode and coalesce to form a gas phase film. The gas phase film undergoes electrical breakdown to establish an electrochemical discharge (21) channel. The flexible tool electrode enters the sampling needle diameter change region (19), the magnetic nanopowder (12) undergoes position rearrangement, the electrochemical discharge (21) etches the micro-nano nested structure (23), the magnetic nanopowder (12) undergoes mechanical grinding, and the electrochemical discharge (21) thermal field induces the formation of a silver antibacterial coating (24). The flexible tool electrode is detached from the sampling needle tube (13), the sampling needle tube (13) is cleaned and the silver antibacterial coating (24) is dried and cured to obtain a variable cross-section sampling needle tube (13) with hydrophobic and antibacterial functions.

2. The method for synergistic preparation of electrochemical discharge additives and subtractives on the inner wall of a variable cross-section sampling needle according to claim 1, characterized in that, The electrolyte (15) preparation steps are as follows: silver nitrate crystals are dissolved in deionized water to prepare the silver nitrate solution, and the low surface energy substance (20) is added. The assembly of the flexible tool electrode is specifically as follows: the magnetic electrode handle (11) is inserted into the electrode chuck (10), and the magnetic magnetic force of the magnetic electrode handle (11) captures the magnetic nanopowder (12).

3. The method for synergistic preparation of electrochemical discharge additives and subtractives on the inner wall of a variable cross-section sampling needle according to claim 1, characterized in that, The vapor phase film formation process is as follows: oxygen bubbles (17) are generated on the surface of the auxiliary electrode (4), hydrogen bubbles (18) are generated on the surface of the flexible tool electrode, the generation rate of the hydrogen bubbles (18) is greater than the detachment rate of the hydrogen bubbles (18), and the hydrogen bubbles (18) coalesce and fuse on the outer surface of the flexible tool electrode.

4. The method for synergistic preparation of electrochemical discharge additives and subtractives on the inner wall of a variable cross-section sampling needle according to claim 1, characterized in that, The specific position rearrangement is as follows: a rigid mechanical extrusion force is applied to the inner wall of the sampling needle tube (13), the value of which is greater than the magnetic dipole interaction force between the magnetic nanopowders (12), and the magnetic nanopowders (12) slide radially inward along the magnetic electrode handle (11) under the force.

5. The method for synergistic preparation of electrochemical discharge additives and subtractives on the inner wall of a variable cross-section sampling needle according to claim 1, characterized in that, The formation of the silver antibacterial coating (24) is specifically achieved by: the electrochemical discharge (21) heating the electrolyte (15) in a thermal field; the silver nitrate solution decomposes and releases elemental silver particles that aggregate into antibacterial particles (22); the antibacterial particles (22) are mixed with the low surface energy material (20); and the mixed material is deposited on the surface and pores of the micro-nano nested structure (23).

6. A variable cross-section sampling needle inner wall electrochemical discharge additive / subtractive material co-processing device, characterized in that, The method for preparing a variable cross-section sampling needle inner wall electrochemical discharge additive and subtractive material synergistically according to any one of claims 1-5 includes a processing platform base (6), an XYZ three-axis motion platform (5), an electrolyte tank (3), a rotating spindle (7), and an adjustable pulse power supply (1). The processing platform base (6) is connected to the XYZ three-axis motion platform (5). The XYZ three-axis motion platform (5) is equipped with the electrolyte tank (3). The electrolyte tank (3) has a fixed fixture (14). The processing platform base (6) is equipped with the rotating spindle (7). The rotating spindle (7) holds the magnetic electrode handle (11). The magnetic electrode handle (11) adsorbs magnetic nanopowder (12) to form a flexible tool electrode. The adjustable pulse power supply (1) is connected to the auxiliary electrode (4) and the electric bearing (9). The electric bearing (9) is sleeved on the outside of the rotating spindle (7).

7. The electrochemical discharge additive / subtractive material co-processing device for the inner wall of a variable cross-section sampling needle according to claim 6, characterized in that, The XYZ three-axis motion platform (5) is connected to the motion control system (2). The motion control system (2) sends pulse control signals to the XYZ three-axis motion platform (5). The rotating spindle (7) is connected to the motion control system (2). The motion control system (2) adjusts the rotation speed parameters and rotation direction of the rotating spindle (7).

8. The electrochemical discharge additive / subtractive material co-processing device for the inner wall of a variable cross-section sampling needle according to claim 6, characterized in that, The electrolyte tank (3) is connected to the electrolyte circulation system (16). The output end of the electrolyte circulation system (16) is connected to the inside of the electrolyte tank (3), and the input end of the electrolyte circulation system (16) is connected to the drain port of the electrolyte tank (3).

9. The electrochemical discharge additive / subtractive material co-processing device for the inner wall of a variable cross-section sampling needle according to claim 6, characterized in that, The electric bearing (9) enables current transmission between the stationary wire and the rotating spindle (7). The current is transmitted to the electrode chuck (10) via the rotating spindle (7), and the electrode chuck (10) transmits the current to the magnetic electrode handle (11). The magnetic electrode handle (11) transmits the current to the magnetic nanopowder (12).

10. The electrochemical discharge additive / subtractive material co-processing device for the inner wall of a variable cross-section sampling needle according to claim 6, characterized in that, The magnetic electrode handle (11) is made of conductive ferromagnetic material or embedded permanent magnet conductive material, the auxiliary electrode (4) is immersed in electrolyte (15), and the flexible tool electrode constitutes an electrochemical reaction cathode.

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