Magnetic control shape and position tool electrode micro-grinding auxiliary electrolytic polishing device and method

Abstract

The invention provides a magnetic control shape and position tool electrode micro-grinding auxiliary electrolytic polishing device and method.The adopted tool electrode is made of a flexible material and comprises a center silk thread and a winding silk thread, and the center silk thread is conductive and magnetic; the winding wire is an insulator and is wound on the periphery of the central wire, and abrasive particles are arranged on the surface; in the electrolytic polishing process, grinding assistance is implemented through autorotation of the tool electrode; applying a magnetic field to attach the tool electrode to the to-be-polished surface, and controlling the direction of the magnetic field to adjust the position of the tool electrode. The shape of the internal tool electrode and the polishing action position are controlled through the magnetic field outside the flow channel to be matched with the complex structure shape of the shape follow-up flow channel, and efficient and high-quality micro-grinding auxiliary electrolytic polishing is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrolytic composite polishing, and particularly relates to a magnetic control shape tool electrode micro-grinding assisted electrolytic polishing device and method. BACKGROUND

[0002] In modern high-end manufacturing, the inner conformal runner parts play an important role and are widely used in the fields of aerospace, automobile manufacturing, mold processing, etc. For example, the fuel nozzle of an aero-engine optimizes the fuel injection path by means of a conformal runner, improves the combustion efficiency, and reduces fuel consumption and pollutant emissions. Due to the complex structure and irregular internal runner shape of such parts, traditional machining and manufacturing are greatly challenged. Therefore, additive manufacturing technology has attracted great attention. However, due to the influence of factors such as step effect, spheroidization effect, and powder adhesion, the surface roughness of the runner manufactured by additive manufacturing is relatively high, and the general surface roughness Ra is greater than 10 μm, and the size accuracy is about ± 0.5 mm. The rough surface will seriously hinder the smooth flow of fluid in the runner, increase the flow resistance, and reduce the heat or mass transfer efficiency. Therefore, the conformal runner manufactured by additive manufacturing must be polished.

[0003] At present, there are many polishing methods, such as traditional grinding and polishing, abrasive flow polishing, chemical polishing, electrolytic polishing, magnetorheological polishing, ultrasonic polishing, laser polishing, and their combinations / composite polishing, etc. Electrolytic polishing is based on the selective regulation principle of electrochemical anodic dissolution, and through the synergistic effect of the difference in dissolution rate and the dynamic balance of the passivation film, the self-adaptive flattening of the surface micro-geometric morphology and the improvement of the macro-smoothness are realized. However, during electrolytic polishing, the passivation layer on the surface to be polished is easy to produce, and the electrolytic products adhere to the surface, which hinders the next electrolytic reaction and affects the polishing efficiency. At the same time, electrolytic polishing has high requirements for the initial morphology of the surface to be polished, and it is not easy to realize high-quality polishing of the additive forming surface. In addition, the high-strength aluminum alloy manufactured by additive manufacturing has complex material composition, and uneven polishing or local corrosion phenomenon is easy to occur. In view of this, the grinding-assisted electrolytic polishing method is proposed.

[0004] Abrasive assisted electrolytic polishing is a kind of composite polishing method in which abrasive assistance is added in the process of electrolytic polishing to remove the passivation layer and electrolytic product on the surface of electrolytic polishing by abrasive action, so as to improve the efficiency and quality of electrolytic polishing. The abrasive erosion assisted electrolytic polishing method disclosed in the documents such as patents CN112170995B and CN117718550A uses the scraping action of free abrasive particles moving at high speed on the wall surface of the flow channel to complete mechanical abrasive assistance. However, when the free abrasive particles flow at high speed in the contoured flow channel, the flow state is variable, the flow speed and quantity distribution are inconsistent, which leads to low consistency of the abrasive effect on the entire flow channel wall surface, and affects the overall polishing quality. The mechanical abrasive assisted electrolytic polishing method disclosed in the documents such as patents CN108637412B and CN112276265B uses a grinding tool to mechanically grind the flow channel wall surface. However, the shape of the grinding tool is fixed, and it is difficult to adapt to the structural shape change of the contoured flow channel, and the machinability of the curved flow channel and the variable cross-section flow channel is reduced. At present, how to efficiently realize high-quality polishing of the inner surface of the contoured flow channel by additive manufacturing is still a great challenge. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application provides a magnetic shape tool electrode micro-grinding assisted electrolytic polishing device and method to solve the polishing problem of complex inner surfaces such as contoured flow channels.

[0006] The present application achieves the above technical purpose by the following technical means.

[0007] A magnetic shape tool electrode micro-grinding assisted electrolytic polishing method adopts the following tool electrode to perform electrolytic polishing: the tool electrode is made of flexible material and includes a center wire and a winding wire, the center wire is conductive and magnetically conductive; the winding wire is an insulator, is wound around the periphery of the center wire, and has abrasive particles on the surface;

[0008] In the process of electrolytic polishing: abrasive assistance is implemented by self-rotation of the tool electrode; the tool electrode is attached to the surface to be polished by applying a magnetic field, and the position of the tool electrode is adjusted by controlling the orientation of the magnetic field.

[0009] Further, the center wire is an iron-based or nickel-based metal wire.

[0010] Further, the winding wire is a sand line, the surface of which is fixed with diamond abrasive particles, and the winding is helical with a pitch of 2-3 times the diameter of the sand line.

[0011] Further, it is used for polishing of contoured flow channels.

[0012] Further, in the process of electrolytic polishing, electrolyte is injected into the contoured flow channel, the center wire is connected to the negative electrode of the power supply, and the wall surface of the contoured flow channel is connected to the positive electrode of the power supply.

[0013] Further, the magnetic field is applied by setting a magnetic assembly outside the flow channel, and the magnetic field orientation is changed by rotating the magnetic assembly around the flow channel.

[0014] Further, the magnetic assembly is composed of multiple magnets, and the magnetic attraction force on each segment of the tool electrode is controlled by adjusting the spacing between the magnets and the flow channel.

[0015] A magnetic control shape tool electrode micro-grinding assisted electrolytic polishing device, based on the above method, is provided with:

[0016] a tool electrode and a self-rotating driving mechanism thereof;

[0017] a magnetic assembly and a position adjusting mechanism thereof, the magnetic assembly being used to generate the magnetic field.

[0018] Further, the magnetic assembly is composed of multiple magnets, and the spacing between the magnets can be adjusted.

[0019] Further, the position adjusting mechanism can drive the magnetic assembly to rotate around the outside of the workpiece, and the magnetic poles of the magnets are vertically oriented towards the rotation axis.

[0020] The present application has the following advantages:

[0021] (1) The present application provides a magnetic control shape tool electrode micro-grinding assisted electrolytic polishing device and method, which uses the external magnetic field of the flow channel to control the shape and polishing position of the internal tool electrode, to adapt to the complex structure shape of the flow channel, and to achieve high-efficiency and high-quality micro-grinding assisted electrolytic polishing.

[0022] (2) The tool electrode used in the present application has a central wire as a cathode in the electrolytic polishing process, and has good magnetic permeability, which can respond to the magnetic field attraction generated by the external magnetic pole of the flow channel, so that the entire tool electrode is attracted to the inner wall of the flow channel, thereby adapting to the complex structure shape of the flow channel. The diamond abrasive particles fixed on the surface of the sand wire can produce a small amount of grinding action on the flow channel wall; at the same time, the sand wire with insulation characteristics is wound on the surface of the flexible metal wire, which can effectively isolate the flexible metal wire from the flow channel wall, avoid short circuit phenomenon, and ensure stable electrolysis process.

[0023] (3) The present application has higher polishing efficiency and quality. The flexible tool electrode plays a dual role of electrolysis and micro-grinding, and the bare part of the flexible metal wire can react with the flow channel wall to achieve electrolytic polishing. At the same time, the diamond abrasive particles on the surface of the sand wire can perform a small amount of grinding on the flow channel wall, timely remove the electrolysis products on the flow channel wall, thin the passivation layer, break the dynamic balance of the passivation layer to hinder the electrolysis reaction, and accelerate the subsequent electrolysis reaction. The synergistic effect of the two not only improves the polishing efficiency, but also effectively improves the polishing surface quality, and achieves higher quality polishing effect.

[0024] (4) The tool of the present application has stronger adaptability and machining accessibility. The flexible tool electrode has good flexibility and adaptability. The magnetic control shape adjustment of the external magnetic pole can tightly fit the inner wall shape of the conformal flow channel. Whether the flow channel inside the complex part manufactured by additive manufacturing, the curved pipeline or the variable cross-section flow channel, the electrode can effectively polish, solve the problem that the traditional grinding tool is difficult to adapt to the shape change of the conformal flow channel due to the fixed shape, and has low machining accessibility for curved flow channels and variable cross-section flow channels, greatly improving the machining accessibility of the complex shape flow channel and the adaptability of the tool.

[0025] (5) The overall polishing uniformity and integrity of the present application is better. The external magnetic pole is composed of multiple independent magnetic pole heads. On the one hand, the magnetic field strength of a single magnetic pole head can be adjusted according to the distance between the magnetic pole head and the flexible tool electrode, and on the other hand, the placement position of a single magnetic pole head can be adjusted according to the shape of the conformal flow channel, so as to ensure that the magnetic field attraction of each section of the dual-purpose flexible tool electrode is the same, so that the polishing force of each part of the tool electrode is uniform when moving on the inner wall surface of the conformal flow channel, and the tool electrode can uniformly adhere to the inner wall of the flow channel, effectively avoiding uneven polishing or local corrosion phenomenon, and improving the overall polishing uniformity. At the same time, during the entire polishing process, the tool electrode rotates around its center, and the external magnetic pole slowly rotates around the outside of the conformal flow channel, which can fully polish the inner wall surface of the conformal flow channel, ensuring the integrity of the polishing. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a structural schematic diagram of the tool electrode of the present application;

[0027] Figure 2 is a structural principle diagram of the micro-grinding assisted electrolytic polishing device of the present application;

[0028] Figure 3 is a polishing process state change diagram relative to Figure 2 .

[0029] REFERENCE NUMERALS:

[0030] 1-Tool electrode; 11-Central wire; 12-Wound wire; 13- Abrasive particles;

[0031] 2-Conformal flow channel; 3-Magnetic force assembly; 31-Magnet; 4-Electrolyte;

[0032] 5-Power supply. DETAILED DESCRIPTION

[0033] Embodiments of the present application are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0034] I. Method

[0035] As Figure 1 The tool electrode 1 used in the micro-grinding assisted electrolytic polishing of the present application includes a center wire 11 and a winding wire 12, both of which are flexible materials, so that the tool electrode 1 can be freely bent. Among them:

[0036] The center wire 11 is a conductor, which can specifically use flexible metal wires with high magnetic permeability such as iron-based and nickel-based;

[0037] The winding wire 12 is an insulator, which is spirally wound around the center wire 11 and uniformly distributed with abrasive particles 13 on the surface; specifically, a sand line with surface-bonded diamond abrasive particles can be spirally wound, and the pitch is 2-3 times the diameter of the winding wire 12.

[0038] As Figure 2 and Figure 3 Taking the conformal flow channel as an example, the micro-grinding assisted electrolytic polishing of the present application is realized by the following means:

[0039] The conformal flow channel 2 as an example object can be an integrated flow channel inside an additively manufactured complex component, or a curved pipe, a variable cross-section flow channel, etc. The material is high-strength aluminum alloy such as AlMgSc and AlSi10Mg.

[0040] The above tool electrode 1 penetrates into the conformal flow channel 2, and the center wire 11 is connected to the negative electrode of the power supply 5. The conformal flow channel 2 is injected with electrolyte 4, and the wall surface of the conformal flow channel 2 is connected to the positive electrode of the power supply 5.

[0041] The magnetic assembly 3 is arranged outside the conformal flow channel 2 to form a magnetic field to attract the center wire 11, so that the tool electrode 1 is tightly attached to the inner wall of the conformal flow channel 2. The magnetic assembly 3 can rotate around the conformal flow channel 2, and its rotation speed is ω2, thereby driving the tool electrode 1 to displace around the inner wall of the conformal flow channel 2.

[0042] The magnetic assembly 3 can be composed of a plurality of independent magnets 31, the magnetic poles of which are perpendicular to the rotation axis of the magnetic assembly 3 (i.e. towards the conformal flow channel 2); the spacing positions of each magnet 31 to the conformal flow channel 2 can be independently adjusted, so that the magnetic attraction force received by each section of the tool electrode 1 is uniform.

[0043] In operation, on one hand, an electrolytic reaction of anode dissolution occurs in the electrolyte environment to perform electrolytic polishing on the inner wall surface of the runner 2. On the other hand, the tool electrode 1 rotates at a rotational speed of ω1, and the abrasive grains 13 perform micro-grinding on the inner wall of the runner 2. Meanwhile, the magnetic assembly 3 is rotated to adjust the position of the tool electrode 1, so as to timely remove the electrolytic products generated in each position and thin the surface passivation layer, thereby accelerating the subsequent electrolytic reaction.

[0044] II. Device

[0045] Based on the above-mentioned micro-grinding assisted electrolytic polishing method, a micro-grinding assisted electrolytic polishing device is designed, which comprises:

[0046] The tool electrode 1 and the self-rotation driving mechanism thereof are used to drive the tool electrode 1 to rotate by itself.

[0047] The magnetic assembly 3 and the position adjusting mechanism thereof are used to adjust the position of the magnetic assembly 3, so that the magnetic assembly 3 can rotate around the outside of the workpiece (such as the runner).

[0048] The electrolytic assembly comprises a power supply 5 and an electrolyte injection mechanism for injecting electrolyte into the workpiece.

[0049] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0050] The present application is not limited to the above-mentioned embodiments, and any obvious improvements, replacements or modifications made by those skilled in the art without departing from the essential content of the present application shall fall within the protection scope of the present application.

Claims

1. A method for electrolytic polishing assisted by micro-grinding of a magnetically controlled form-position tool electrode, characterized in that: Electrolytic polishing is performed using the following tool electrode (1): the tool electrode (1) is made of a flexible material and comprises a central wire (11) and a winding wire (12); the central wire (11) is electrically conductive and magnetic; the winding wire (12) is an insulator, wound around the outer periphery of the central wire (11), and has abrasive grains (13) on its surface; During the electrolytic polishing process: grinding assistance is implemented by rotating the tool electrode (1); the tool electrode (1) is attached to the surface to be polished by applying a magnetic field, and the position of the tool electrode (1) is adjusted by controlling the orientation of the magnetic field.

2. The method for electrolytic polishing assisted by micro-grinding of a magnetically controlled form-position tool electrode according to claim 1, characterized in that: The central wire (11) is an iron-based or nickel-based metal wire.

3. The method for electrolytic polishing assisted by magnetically controlled form-position tool electrode micro-grinding according to claim 1, characterized in that: The winding wire (12) is a sand wire with diamond abrasive grains fixed on its surface, which is spirally wound with a pitch of 2 to 3 times the diameter of the sand wire.

4. The method for electrolytic polishing assisted by micro-grinding of a magnetically controlled form-position tool electrode according to claim 1, characterized in that: Used for polishing conformal flow channels.

5. The method for electrolytic polishing assisted by micro-grinding of a magnetically controlled form-position tool electrode according to claim 4, characterized in that: During electrolytic polishing, electrolyte is injected into the conformal flow channel, the central wire (11) is connected to the negative pole of the power supply, and the wall surface of the conformal flow channel is connected to the positive pole of the power supply.

6. The method for electrolytic polishing assisted by micro-grinding of a magnetically controlled form-position tool electrode according to claim 4, characterized in that: The magnetic field is applied by arranging a magnetic component (3) outside the conformal flow channel, and the orientation of the magnetic field is changed by rotating the magnetic component (3) around the conformal flow channel.

7. The method for electrolytic polishing assisted by magnetically controlled form-position tool electrode micro-grinding according to claim 6, characterized in that: The magnetic assembly (3) is composed of a plurality of magnets (31), and the magnitude of the magnetic attraction force exerted on each section of the tool electrode (1) is controlled by adjusting the distance between each magnet (31) and the conformal flow channel.

8. A magnetically controlled form-position tool electrode micro-grinding assisted electrolytic polishing device, characterized in that: Electrolytic polishing is carried out according to any one of claims 1 to 7, comprising: A tool electrode (1) and a rotation drive mechanism thereof; A magnetic component (3) and a position adjustment mechanism thereof, wherein the magnetic component (3) is used to generate the magnetic field.

9. The magnetically controlled form-position tool electrode micro-grinding assisted electrolytic polishing device according to claim 8, characterized in that: The magnetic assembly (3) is composed of a plurality of magnets (31), and the spatial positions between the magnets (31) are adjustable.

10. The magnetically controlled form-position tool electrode micro-grinding assisted electrolytic polishing device according to claim 8, characterized in that: The position adjustment mechanism can drive the magnetic assembly to rotate around the outside of the workpiece, with the magnetic poles of each magnet facing vertically toward the rotation axis.

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