Liquid metal abrasive particle flow processing device and method based on Halbach magnetic field

Abstract

The invention discloses a liquid metal abrasive particle flow machining device and method based on a Halbach magnetic field. The problem that in the prior art, the polishing uniformity of a complex curved surface is poor is solved. The machining device comprises a platform frame, a mounting plate is arranged on the platform frame, a visual machining module is arranged on the mounting plate, and the two ends of the visual machining module are in linkage with driving air cylinders through push rod assemblies. The visual machining module comprises a closed profiling constraint runner formed by transparent acrylic plates, a workpiece to be machined is fixed in the runner, and the two ends of the runner are connected with piston rods of the driving air cylinders through push rod assemblies. A Halbach permanent magnet array is arranged below the workpiece, and the Halbach permanent magnet array is formed by neodymium iron boron permanent magnets according to a Halbach polarity arrangement mode and used for generating a strong gradient directional magnetic field with one side enhanced and the back side weakened in a machining area.

Description

Technical Field

[0001] This invention belongs to the field of precision and special processing technology, specifically relating to a liquid metal abrasive flow processing device and method based on a Halbach magnetic field. Background Technology

[0002] In fields such as biomedicine, aerospace, and high-end equipment manufacturing, parts with complex three-dimensional shapes (such as artificial joints, engine blades, and precision molds) are increasingly widely used. These parts typically need to meet stringent requirements such as ultra-smooth surfaces, high dimensional accuracy, and non-damaging surfaces, and their machining quality directly affects the service life and performance of the components.

[0003] Currently, polishing methods for complex curved surfaces mainly include manual polishing and automated machine polishing. Manual polishing methods are highly dependent on the operator's experience and suffer from problems such as low efficiency, poor consistency, and high labor intensity. Automated machine polishing, such as processes using non-Newtonian fluids or soft polishing pads, has improved efficiency to some extent, but still faces significant challenges when dealing with parts with large curvature changes and complex geometries.

[0004] During the contact process between fluids or soft abrasives and the workpiece, areas with protrusions or low curvature experience greater pressure and shear forces, resulting in higher material removal rates. Conversely, areas with depressions, grooves, or severe curvature tend to form "weak flow zones" or "machining blind zones," leading to insufficient abrasive kinetic energy and difficulty in material removal. This inherent "edge effect" makes it difficult to guarantee the polishing uniformity of the entire joint surface, resulting in significant differences in surface quality between regions and hindering further performance improvements in high-end artificial joint products.

[0005] Therefore, there is an urgent need in this field to develop a new polishing technology that can adapt to complex curved surface morphology and accurately compensate energy in weak flow regions, so as to break through the bottleneck of existing processes in terms of processing uniformity. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention aims to provide a liquid metal abrasive flow machining device and method based on a Halbach magnetic field, thereby solving the problem of poor uniformity in polishing complex curved surfaces in existing technologies. This invention employs a composite abrasive flow composed of SiC microparticles, liquid metal doped with magnetic nanoparticles, and a basic liquid phase fluid. A strong gradient directional magnetic field is formed on one side below the workpiece using a Halbach array, generating magnetic volume force on the flowing magnetic liquid metal. This force drives the metal to accelerate and propel it towards the weak flow region on the workpiece surface, achieving active control of the abrasive trajectory and precise energy injection.

[0007] The objective achieved by this invention can be accomplished through the following specific technical solutions: On one hand, the present invention provides a liquid metal abrasive flow machining device based on a Halbach magnetic field, including a platform frame, a mounting plate on the platform frame, and a visualization machining module on the mounting plate. Both ends of the visualization machining module are linked to a drive cylinder through push rod assemblies. The visualization machining module includes a closed contour-conforming constraint flow channel made of transparent acrylic plate, in which a workpiece to be processed is fixed. Both ends of the flow channel are connected to the piston rod of the drive cylinder through push rod assemblies. Furthermore, a Halbach permanent magnet array is provided below the workpiece. The Halbach permanent magnet array is composed of neodymium iron boron permanent magnets arranged in a Halbach polarity manner to generate a strong gradient directional magnetic field with unilateral enhancement and back-side weakening in the machining area.

[0008] Furthermore, an air supply unit is provided on the platform frame. The air supply unit is connected to the drive cylinder and a multi-stage filter on the mounting plate via an air pipe. The multi-stage filter includes an air filter, a pressure reducing valve, and an oil mist lubricator, which are used to intercept and remove particulate matter, liquid water, oil mist / oil vapor, odor / organic matter from the compressed air in stages, thereby purifying the compressed air.

[0009] Furthermore, the push rod assembly includes a slidingly fitted guide sleeve and a piston rod. One end of the guide sleeve is connected to a flow channel connector via a flange, and the other end is through which the piston rod moves. The end of the piston rod that passes through the guide sleeve is connected to the output end of the drive cylinder via a Y-shaped connector. A microporous filter is provided at the connection between the guide sleeve and the flow channel connector, and the flow channel connector is connected to the flow channel of the visualization processing module.

[0010] Furthermore, the mounting plate is also equipped with an integrated controller, which integrates a power module, a signal conditioning system and a pulse control interface for controlling the reciprocating frequency and stroke of the drive cylinder.

[0011] On the other hand, the present invention provides a liquid metal abrasive flow machining method based on a Halbach magnetic field, implemented by the aforementioned liquid metal abrasive flow machining device based on a Halbach magnetic field, comprising the following steps: Step 1: Assemble the processing device and fix the workpiece in the contour constraint flow channel of the visualization processing module; Step 2: Inject magnetic liquid metal composite abrasive working medium into the contour-following constrained flow channel; Step 3: Turn on the processing device, set the parameters through the integrated controller, start the power system, and make the drive cylinder drive the piston rod of the push rod assembly to reciprocate, driving the composite abrasive flow to reciprocate at high speed in the contour constraint channel, so as to perform turbulent shearing and scouring on the workpiece surface. Step 4: After processing is complete, turn off the device and remove the workpiece.

[0012] Further, in step 2, the working medium preparation process is as follows: First, magnetic nanoparticles are uniformly dispersed in room temperature liquid metal to form a magnetic response phase; then, the magnetic liquid metal component, micron-sized SiC abrasive particles, and incompressible basic liquid phase fluid are mixed (preferably, 5% magnetic liquid metal and 10% micron-sized SiC abrasive particles), and the mixture is fully mixed by mechanical stirring and ultrasonic vibration to form a composite abrasive flow.

[0013] Furthermore, in the processing of step 3, a strong gradient directional magnetic field is generated using a Halbach permanent magnet array to apply magnetic volume force to the magnetic liquid metal component in the flowing composite abrasive flow, thereby directionally accelerating and controlling the trajectory of the magnetic liquid metal component, so that the magnetic liquid metal component impacts the weak flow region on the workpiece surface at high speed, achieving synergistic material removal under magnetic field enhancement.

[0014] Furthermore, in step 3, an intermittent processing mode is adopted. During the processing, the flow field is observed in real time through a visual processing module, and the surface morphology of the workpiece is periodically checked until the predetermined processing requirements are met.

[0015] Compared with the prior art, the present invention has the following advantages: (1) This invention utilizes the strong gradient magnetic field of the Halbach array to directionally energize the liquid metal abrasive flow, precisely injecting energy into the processing blind zone and weak flow zone in the traditional process, which significantly improves the polishing uniformity of complex curved surfaces; the composite abrasive flow with liquid metal as carrier is adopted, and its high density characteristics are used to fundamentally suppress the sedimentation and agglomeration of magnetic particles, ensuring the stability of the medium and the repeatability of the processing.

[0016] (2) This invention improves material removal efficiency and achieves high consistency and low damage processing of workpiece surface by using the synergistic mechanism of magnetic field directional impact and fluid global shearing. It adopts modular and visual design, which has good reconfigurability and process observation capability, and provides convenience for process optimization. Attached Figure Description

[0017] Figure 1 This is a general structural diagram and a partial enlarged view of the device of the present invention; Figure 2 This is a structural diagram of the multi-stage filter in this invention; Figure 3 This is a structural diagram and cross-sectional view of the dual-cylinder drive unit in this invention; Figure 4 This is a structural diagram and cross-sectional view of the transparent visualization processing module in this invention; Figure 5 This is a cross-sectional view of the push rod assembly structure in this invention; Figure 6This is a schematic diagram illustrating the principle of liquid metal abrasive flow machining under Halbach magnetic field control in this invention. Figure 7 This is a schematic diagram of the microscopic principle of liquid metal abrasive flow machining in this invention.

[0018] In the diagram: 1-Platform frame, 2-Mounting plate, 3-Visual processing module, 31-Upper flow channel, 32-Lower flow channel, 4-Push rod assembly, 41-Guide sleeve, 42-Piston rod, 43-Flow channel connector, 44-Y-type connector, 45-Microporous filter, 5-Drive cylinder, 51-Solenoid directional valve, 52-Throttle speed control valve, 6-Workpiece, 7-Air supply unit, 8-Multi-stage filter, 81-Filter, 82-Pressure reducing valve, 83-Oil mist lubricator, 9-Halbach permanent magnet array, 10-Integrated controller. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] Example 1

[0021] like Figure 1 As shown, this embodiment provides a liquid metal abrasive flow machining device based on a Halbach magnetic field, including a platform frame 1, a mounting plate 2 on the platform frame 1, and a visualization machining module 3 on the mounting plate 2. Both ends of the visualization machining module 3 are linked to the drive cylinder 5 via push rod assemblies 4. The visualization machining module 3 includes a closed contour-following constraint flow channel made of transparent acrylic plate, with a workpiece 6 to be processed fixed inside the flow channel. Both ends of the flow channel are connected to the piston rod of the drive cylinder 5 via push rod assemblies 4. A Halbach permanent magnet array 9 is located below the workpiece 6. The Halbach permanent magnet array 9 is composed of neodymium iron boron permanent magnets arranged in a Halbach polarity pattern, used to generate a strong gradient directional magnetic field with unilateral enhancement and back-side weakening in the machining area. An integrated controller 10 is also provided on the mounting plate 2. The integrated controller 10 integrates a power module, a signal conditioning system, and a pulse control interface for controlling the reciprocating frequency and stroke of the drive cylinder 5.

[0022] An air supply unit 7 is installed on the platform frame 1. The air supply unit 7 is connected to the drive cylinder 5 and the multi-stage filter 8 installed on the mounting plate 2 via air pipes. Figure 2As shown, the multi-stage filter 8 includes an air filter 81, a pressure reducing valve 82, and an oil mist lubricator 83. The air filter 81 and the oil mist lubricator 83 are respectively located at both ends. The air filter 81 at one end of the multi-stage filter 8 is connected to the air supply unit 7, and the oil mist lubricator 83 at the other end is connected to the solenoid reversing valve 51 of the drive cylinder 5. It is used to intercept and remove particulate matter, liquid water, oil mist / oil vapor, odor / organic matter from the compressed air in stages, thereby purifying the compressed air. In this embodiment, the inner diameter of the air pipe is 12 mm, supplemented by a 10 mm branch to improve the adjustment accuracy. Each drive cylinder 5 is equipped with a throttle speed control valve at the inlet / outlet to achieve synchronous control of the movement of the left and right cylinders.

[0023] like Figure 3 As shown, the drive cylinder 5 is equipped with an electromagnetic reversing valve 51 and a throttle speed control valve 52 to ensure stable air supply and accurate synchronous control. Figure 4 As shown, the visualization processing module 3 is located between the two pusher assemblies 4. It is constructed of high-transparency acrylic material to form a closed contour-containment flow channel, including an upper flow channel 31 and a lower flow channel 32. The upper flow channel 31 and the lower flow channel 32 are closed by a high-flatness acrylic plate. Its shape precisely matches the curved surface of the workpiece 6 to be processed, which not only ensures the closedness and controllability of the processing, but also provides the necessary conditions for real-time observation of the micro-flow behavior and magnetic response state of the abrasive flow. The Halbach permanent magnet array 9 is installed directly below the workpiece 6. It is composed of neodymium iron boron permanent magnets arranged in a specific polarity, which can establish a high-gradient directional magnetic field in the central region of the flow channel, which is enhanced on one side and weakened on the back side.

[0024] like Figure 5 As shown, the push rod assembly 4 includes a slidingly fitted guide sleeve 41 and a piston rod 42. One end of the guide sleeve 41 is connected to the flow channel connector 43 via a flange, and the other end allows the piston rod 42 to pass through. The end of the piston rod 42 that passes through the guide sleeve 41 is connected to the output end of the drive cylinder 5 via a Y-type connector 44, ensuring coaxial stability and mechanical coordination during power transmission. A microporous filter 45 is provided at the connection between the guide sleeve 41 and the flow channel connector 43, and the flow channel connector 43 is connected to the flow channel of the visualization processing module 3.

[0025] like Figure 6 The image shows the machining trajectory of liquid metal abrasive flow under Halbach magnetic field control. The mechanism of this invention is as follows: Under the drive of dual cylinders, liquid metal doped with magnetic nanoparticles works in synergy with the Halbach permanent magnet array to construct a unilaterally oriented high-gradient magnetic field on one side of the workpiece. This concentrates the magnetic volume force on the weak flow region, causing the magnetic liquid metal particles to accelerate directionally and achieve spatial focusing. Furthermore, the particles synergistically enhance the energy of surrounding abrasive particles through dragging and collision.

[0026] like Figure 7The diagram illustrates the microscopic process of liquid metal abrasive flow machining. Magnetic liquid metal, under the influence of a magnetic field, carries SiC abrasive grains to impact the workpiece surface, removing protrusions and thus achieving surface polishing. The magnetic field is concentrated in the center of the workpiece, allowing the accelerated medium to carry higher kinetic energy and precisely impact the weak flow region on the workpiece surface. This significantly increases the effective kinetic energy and turbulent kinetic energy of the abrasive grains in that region, as well as the erosion rate. Ultimately, this achieves a synergistic removal mechanism of "global shearing + local reinforcement," significantly improving the polishing uniformity of complex curved surfaces.

[0027] Example 2

[0028] This embodiment provides a liquid metal abrasive flow machining method based on a Halbach magnetic field, implemented using the liquid metal abrasive flow machining device based on a Halbach magnetic field as described in Embodiment 1. The method of this embodiment includes the following steps: Step 1: Assemble the processing device and fix the workpiece 6 in the contour constraint flow channel of the visualization processing module 3.

[0029] The visualization processing module 3 is made of high-transparency acrylic material and manufactured through 3D modeling and precision machining technology. The shape of the contour-constrained flow channel precisely matches the surface to be processed on the workpiece 6. The Halbach permanent magnet array 9 is composed of neodymium iron boron (NdFeB) permanent magnets arranged in a specific polarity sequence (preferably, each permanent magnet can be rotated 90° sequentially).

[0030] Step 2: Fill the contour-following constrained flow channel with magnetic liquid metal composite abrasive working medium.

[0031] The working medium is prepared by mixing dispersed SiC microparticles, a liquid metal component doped with magnetic nanoparticles, and an incompressible base liquid fluid at predetermined volume fractions. The preparation process of the working medium is as follows: First, magnetic nanoparticles are uniformly dispersed in room temperature liquid metal to form a magnetically responsive phase; then, the magnetic liquid metal component, micron-sized SiC abrasive particles, and incompressible base liquid fluid are mixed, with a preferred mixing ratio of 5% magnetic liquid metal and 10% micron-sized SiC abrasive particles. The mixture is thoroughly mixed by mechanical stirring and ultrasonic vibration to form a composite abrasive flow.

[0032] Step 3: Turn on the processing device, set the parameters through the integrated controller 10, start the power system, so that the drive cylinder 5 drives the piston rod 42 of the push rod assembly 4 to reciprocate, drive the composite abrasive flow to reciprocate at high speed in the contour constraint channel (the flow rate is adjustable), so as to perform turbulent shearing and scouring on the curved surface of the workpiece 6.

[0033] During the processing, a strong gradient directional magnetic field is generated by the Halbach permanent magnet array 9 to apply magnetic volume force to the magnetic liquid metal components in the composite abrasive flow, thereby directional acceleration and trajectory control of the magnetic liquid metal components. This allows the magnetic liquid metal components to impact the weak flow areas such as depressions and corners on the surface of the workpiece 6 at high speed, achieving synergistic material removal under magnetic field enhancement.

[0034] The power system of the integrated controller 10 adopts an intermittent processing mode (that is, after continuous processing for many hours, it can be paused to observe the processing details and use a surface profilometer to measure the surface morphology of a specified area). During the processing, the flow field is observed in real time through the visualization processing module 3, and the surface morphology of the workpiece 6 is checked periodically until the predetermined processing requirements are met.

[0035] Step 4: After processing is complete, turn off the device and remove the workpiece 6.

[0036] The processing principle of this embodiment is as follows: the unilateral enhanced magnetic field generated by the Halbach array applies a magnetic volume force to the flowing magnetic liquid metal. This magnetic volume force produces a directional acceleration effect on the working medium, significantly increasing the movement speed of the abrasive particles relative to the workpiece surface and the effective collision frequency. This directional impact directly energized by the magnetic field, combined with the turbulent shearing effect of the fluid itself, forms a synergistically enhanced material removal mechanism, effectively solving the problem of insufficient kinetic energy in weak flow regions.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid metal abrasive flow machining device based on a Halbach magnetic field, comprising a platform frame (1), wherein a mounting plate (2) is disposed on the platform frame (1), characterized in that, The mounting plate (2) is provided with a visualization processing module (3). Both ends of the visualization processing module (3) are linked to the drive cylinder (5) through push rod assembly (4). The visualization processing module (3) includes a closed contour constraint flow channel made of transparent acrylic plate. The workpiece (6) to be processed is fixed in the flow channel. Both ends of the flow channel are connected to the piston rod of the drive cylinder (5) through push rod assembly (4). A Halbach permanent magnet array (9) is provided below the workpiece (6). The Halbach permanent magnet array (9) is composed of neodymium iron boron permanent magnets arranged in Halbach polarity and is used to generate a strong gradient directional magnetic field with unilateral enhancement and back-side weakening in the processing area.

2. The abrasive flow machining device for liquid metal under a Halbach magnetic field according to claim 1, characterized in that, An air supply unit (7) is provided on the platform frame (1). The air supply unit (7) is connected to the drive cylinder (5) and the multi-stage filter (8) provided on the mounting plate (2) through an air pipe. The multi-stage filter (8) includes an air filter (81), a pressure reducing valve (82) and an oil mist lubricator (83), which are used to intercept and remove particulate matter, liquid water, oil mist / oil vapor, odor / organic matter in the compressed air step by step, and purify the compressed air.

3. The abrasive flow machining device for liquid metal under a Halbach magnetic field according to claim 1, characterized in that, The push rod assembly (4) includes a slidingly fitted guide sleeve (41) and a piston rod (42). One end of the guide sleeve (41) is connected to the flow channel connector (43) via a flange, and the other end is for the piston rod (42) to pass through. The end of the piston rod (42) that passes through the guide sleeve (41) is connected to the output end of the drive cylinder (5) via a Y-type connector (44). A microporous filter (45) is provided at the connection between the guide sleeve (41) and the flow channel connector (43). The flow channel connector (43) is connected to the flow channel of the visualization processing module (3).

4. The abrasive flow machining device for liquid metal under a Halbach magnetic field according to claim 1, characterized in that, An integrated controller (10) is also provided on the mounting plate (2). The integrated controller (10) integrates a power module, a signal conditioning system and a pulse control interface, which are used to control the reciprocating frequency and stroke of the drive cylinder (5).

5. A liquid metal abrasive flow machining method based on a Halbach magnetic field, implemented by the liquid metal abrasive flow machining device based on a Halbach magnetic field as described in any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Assemble the processing device and fix the workpiece (6) in the contour constraint flow channel of the visualization processing module (3); Step 2: Inject magnetic liquid metal composite abrasive working medium into the contour-following constrained flow channel; Step 3: Turn on the processing device, set the parameters through the integrated controller (10), start the power system, and make the drive cylinder (5) drive the piston rod (42) of the push rod assembly (4) to reciprocate, drive the composite abrasive flow to reciprocate at high speed in the contour constraint channel, so as to perform turbulent shearing and scouring on the curved surface of the workpiece (6); Step 4: After processing is completed, turn off the device and remove the workpiece (6).

6. The abrasive flow machining method for liquid metal based on a Halbach magnetic field according to claim 5, characterized in that, In step 2, the working medium preparation process is as follows: First, magnetic nanoparticles are uniformly dispersed in room temperature liquid metal to form a magnetic response phase; then, the magnetic liquid metal component, micron-sized SiC abrasive particles, and incompressible basic liquid phase fluid are mixed, and the mixture is fully mixed by mechanical stirring and ultrasonic vibration to form a composite abrasive flow.

7. The abrasive flow machining method for liquid metal based on a Halbach magnetic field according to claim 5, characterized in that, In the processing of step 3, a strong gradient directional magnetic field is generated by the Halbach permanent magnet array (9) to apply magnetic volume force to the magnetic liquid metal component in the composite abrasive flow, thereby directional acceleration and trajectory control of the magnetic liquid metal component, so that the magnetic liquid metal component impacts the weak flow area on the surface of the workpiece (6) at high speed, and achieves synergistic material removal under magnetic field enhancement.

8. The abrasive flow machining method for liquid metal based on a Halbach magnetic field according to claim 5, characterized in that, In step 3, an intermittent processing mode is adopted. During the processing, the flow field is observed in real time through the visualization processing module (3), and the surface morphology of the workpiece (6) is checked periodically until the predetermined processing requirements are met.

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