A magnetic shear thickening polishing device and method based on air gap excitation alternating magnetic field

Abstract

The application discloses a magnetic shear thickening polishing device and method based on air gap excitation alternating magnetic field, and belongs to the technical field of magnetic field assisted polishing. In view of the problems of weak magnetic field intensity and difficult adjustment in magnetic shear thickening polishing, the magnetic field generating device is optimized, the magnetic field adjustment technology is introduced, the magnetic shear thickening polishing device and method of air gap excitation alternating magnetic field are provided, and the device composed of a six-degree-of-freedom industrial robot, an electric spindle, a workpiece clamp, a magnetic field generating device, a precision displacement platform, a demagnetizing shell, a medium baffle, a strip-shaped magnetic yoke, a permanent magnet, a vertical bearing, a base, a large pulley, a small pulley, a synchronous belt, a motor support, a servo motor and a permanent magnet support is designed; the high-performance magnetic shear thickening polishing medium is utilized; and the alternating magnetic field generated by double magnetic pole rotation is combined to realize the magnetic shear thickening polishing on the surface of a workpiece in the alternating magnetic field. The application can be applied to the magnetic field regulation and control and medium updating of the magnetic shear thickening polishing.

Description

Technical Field

[0001] This invention relates to magnetic field-assisted polishing technology, specifically to a magnetic shearing thickening polishing device and method based on an air gap excitation alternating magnetic field. Background Technology

[0002] Magnetic field-assisted polishing (MF-assisted polishing) is a technique that uses a magnetic field to control the polishing medium, thereby achieving high-precision and uniform polishing of the workpiece surface. This technology aims to reduce surface roughness, remove scratches and microcracks, improve surface physical and mechanical properties, and optimize surface stress distribution. It is a promising machining process in the fields of precision and ultra-precision machining. The magnetic field generator, as one of the core components of MF-assisted polishing, generates and adjusts the intensity and distribution of the magnetic field to apply controlled forces to magnetorheological fluids or magnetic abrasives, creating uniform shear force and pressure on the workpiece surface, thus achieving high-precision polishing. This device can handle complex shapes and high-hardness materials, and can reduce the impact of mechanical stress and thermal effects on the workpiece without contact, ensuring the accuracy and consistency of the polishing process.

[0003] The magnetic field in common magnetic field generating devices can be excited by permanent magnets or electromagnets. To optimize the size of the magnetic field generating device and save costs, most existing designs use permanent magnets as the magnetic source. Chinese patent CN106826411B proposes a cam-driven magnet-type magnetorheological hydrodynamic polishing device and method, in which the magnet assembly consists of several permanent magnets arranged adjacent to each other with the same or opposite poles. Chinese patent CN113714863B proposes a bidirectional coordinated vibration polishing device and method based on magnetic field coupling, in which the permanent magnet device consists of four detachable spherical magnetic poles. Both of these patents use permanent magnets as the magnetic source for the magnetic field generating device. However, permanent magnets can only provide a constant magnetic field, which limits the properties of the processed material and the self-renewal capability of the magnetic polishing medium. For example, when processing softer materials, excessive magnetic field strength can lead to defects such as abrasive scratches on the workpiece surface. A constant magnetic field strength keeps the magnetic polishing medium in a solidified state, preventing the abrasive particles held by the medium from being renewed in a timely manner. Summary of the Invention

[0004] To address the issues of weak magnetic field strength and difficulty in adjustment during magnetic shear thickening polishing, this paper optimizes the magnetic field generating device, introduces magnetic field adjustment technology, and proposes a magnetic shear thickening polishing device and method with air-gap excitation alternating magnetic field. By utilizing a high-performance magnetic shear thickening polishing medium and combining it with an alternating magnetic field generated by the rotation of two magnetic poles, magnetic shear thickening polishing of the workpiece surface is achieved in an alternating magnetic field.

[0005] The technical solution provided by the present invention for a magnetic shearing thickening polishing device based on an air gap excitation alternating magnetic field is as follows: The device includes a six-degree-of-freedom industrial robot 1, an electric spindle 2, a workpiece clamp 3, a magnetic field generating device 4, and a precision displacement platform 5. The six-degree-of-freedom industrial robot 1 clamps the electric spindle 2 through an end effector. The electric spindle 2 fixes the workpiece clamp 3 through a tool holder and collet structure at its end. The magnetic field generating device 4 is fixed to the precision displacement platform 5 by a T-bolt threaded connection. The magnetic field generating device 4 includes a dielectric baffle 6, a strip magnetic yoke 7, a permanent magnet 8, a permanent magnet support 9, a base 10, a servo motor 11, a motor support 12, and an active... The system includes a wheel 13, a timing belt 14, a driven wheel 15, and a vertical bearing 16. The servo motor 11 is fixed to the base 10 via a motor support 12, and the output shaft of the driving wheel 13 is fixedly connected to the output shaft of the servo motor 11 via a coupling. The driving wheel 13 and the driven wheel 15 are connected via a timing belt 14. The output shaft of the driven wheel 15 is fixedly connected to a permanent magnet bracket 9 containing a permanent magnet 8. Both ends of the permanent magnet bracket 9 are mounted on vertical bearings 16 fixed to the base 10. The strip magnetic yoke 7 is fixed above the permanent magnet bracket 9 and forms an excitation air gap in a symmetrical manner. The medium baffle 6 is installed above the excitation air gap formed by the strip magnetic yoke 7.

[0006] The beneficial effects of this invention are as follows: 1. The magnetic shear thickening polishing device and method based on air-gap excitation alternating magnetic field of this invention utilizes the rotational motion of two permanent magnets to alternately form closed and divergent magnetic circuits at the air gap, thereby achieving the alternating formation of strip-shaped high magnetic field regions and near-zero magnetic field regions in the polishing area. 2. The magnetic shear thickening polishing device and method based on air-gap excitation alternating magnetic field of this invention achieves precise control of the magnetic field strength in the polishing area by adjusting the area of ​​interaction of magnetic flux between the permanent magnet and the strip yoke, and promotes the renewal of abrasive grains during the polishing process, thus improving the polishing quality. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the structure of a magnetic shearing thickening polishing device based on an air gap excitation alternating magnetic field according to the present invention.

[0008] Figure 2 This is a schematic diagram of the magnetic field generating device of a magnetic shearing thickening polishing device based on an air gap excitation alternating magnetic field according to the present invention.

[0009] Figure 3 This is a schematic diagram of the magnetic field distribution mode of a magnetic shearing thickening polishing device based on an air gap excitation alternating magnetic field according to the present invention.

[0010] In the diagram: 1-Six-DOF industrial robot, 2-Electric spindle, 3-Workpiece fixture, 4-Magnetic field generator, 5-Precision displacement platform, 6-Medium baffle, 7-Bar yoke, 8-Permanent magnet, 9-Permanent magnet support, 10-Base, 11-Servo motor, 12-Motor support, 13-Drive wheel, 14-Synchronous belt, 15-Driven wheel, 16-Vertical bearing. Detailed Implementation

[0011] Specific implementation method one: Combining Figure 1 and Figure 2 The device described in this embodiment includes a six-degree-of-freedom industrial robot 1, an electric spindle 2, a workpiece clamp 3, a magnetic field generator 4, and a precision displacement platform 5. The six-degree-of-freedom industrial robot 1 holds the electric spindle 2 via an end effector. The electric spindle 2 fixes the workpiece clamp 3 via a tool holder and collet structure at its end. The magnetic field generator 4 is fixed to the precision displacement platform 5 via T-bolts connected by threads. The magnetic field generator 4 includes a dielectric baffle 6, a strip magnetic yoke 7, a permanent magnet 8, a permanent magnet support 9, a base 10, a servo motor 11, a motor support 12, a drive pulley 13, a synchronous belt 14, and a driven pulley 15. A vertical bearing 16 is provided. The servo motor 11 is fixed to the base 10 via a motor support 12, and the drive wheel 13 is fixedly connected to the output shaft of the servo motor 11 via a coupling. The drive wheel 13 and the driven wheel 15 are connected via a synchronous belt 14. The output shaft of the driven wheel 15 is fixedly connected to a permanent magnet bracket 9 containing a permanent magnet 8. The two ends of the permanent magnet bracket 9 are mounted on the vertical bearing 16 fixed to the base 10. The strip magnetic yoke 7 is fixed above the permanent magnet bracket 9 and forms an excitation air gap in a symmetrical manner. The medium baffle 6 is installed above the excitation air gap formed by the strip magnetic yoke 7.

[0012] Specific Implementation Method Two: Combining Figure 2 and Figure 3 The control of the contact area between the bar yoke 7 and the permanent magnet 8 in this embodiment is achieved by changing the rotation angle of the permanent magnet 8. This change in the contact area affects the magnetic flux at the air gap and thus controls the magnetic field strength. As the servo motor 11 drives the permanent magnet 8 to rotate, and the contact area between the permanent magnet 8 and the bar yoke 7 decreases, the medium reverts to a liquid state. The magnetic particles and abrasive particles within the medium remix, a process known as the medium's self-renewal. As the contact area increases, the medium completes its self-renewal and rearranges to form a magnetic brush. This continuous self-renewal process in the alternating magnetic field ensures the effectiveness of the polishing medium during processing.

[0013] Specific implementation method three: Combining Figure 2 and Figure 3In this embodiment, when the magnetic poles of the permanent magnet 8 are arranged such that the S poles are opposite to the N poles, a closed magnetic circuit is generated at the excitation air gap, forming a strip-shaped high magnetic field region on the surface of the dielectric baffle 6. When the magnetic poles of the permanent magnet 8 are arranged such that the N poles are opposite to each other or the S poles are opposite to each other, a divergent magnetic circuit is generated at the excitation air gap, forming a strip-shaped near-zero magnetic field region on the surface of the dielectric baffle 6. As the permanent magnet 8 continues to rotate, the magnetic circuit at the excitation air gap alternately forms closed and divergent magnetic circuits, and similarly, strip-shaped high magnetic field regions and near-zero magnetic field regions alternately form on the surface of the dielectric baffle 6.

[0014] Specific implementation method four: Combination Figure 1 , Figure 2 and Figure 3 The polishing steps in this embodiment, using the apparatus described in any one of embodiments one, two, or three, are as follows:

[0015] (1) Clamp the workpiece to be polished on the workpiece fixture 3;

[0016] (2) Set the polishing trajectory of the six-degree-of-freedom industrial robot 1 to a Z-shape, the output pulse number of the servo motor 11 to 10000, and the feed speed of the precision displacement platform 5 to 240mm / min;

[0017] (3) Place the magnetic shear thickening polishing medium on the medium baffle 6 to form a "flexible contour particle cluster";

[0018] (4) Start the servo motor 11 so that the permanent magnets 8 are arranged at 45 degrees to form the required magnetic field strength at the excitation air gap;

[0019] (5) Start the six-degree-of-freedom industrial robot 1 and the precision displacement platform 5, control the relative motion between the magnetic shear thickening polishing medium and the workpiece to be polished, and change the magnetic shear thickening polishing medium from "flexible contour particle cluster" to "enhanced flexible contour particle cluster" to process the workpiece to be polished;

[0020] (6) Start the servo motor 11 to gradually turn the arrangement of the permanent magnets 8 to N poles facing each other or S poles facing each other, so as to complete the renewal of abrasive particles during the polishing process.

[0021] (7) After the abrasive particles are replaced, the arrangement of the permanent magnets 8 is rotated to 45 degrees;

[0022] (8) Repeat steps 5 to 7 until the processing requirements of the workpiece to be polished are met.

[0023] The present invention has been described above by way of example with reference to the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-described manner. Various non-substantial improvements made using the inventive concept and technical solutions, or the direct application of the inventive concept and technical solutions to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A magnetic shearing thickening and polishing device based on an air-gap excitation alternating magnetic field, characterized in that: The device includes a six-degree-of-freedom industrial robot (1), an electric spindle (2), a workpiece clamp (3), a magnetic field generator (4), and a precision displacement platform (5). The six-degree-of-freedom industrial robot (1) clamps the electric spindle (2) through an end effector. The electric spindle (2) fixes the workpiece clamp (3) through a tool holder and collet structure at its end. The magnetic field generator (4) is fixed to the precision displacement platform (5) by a T-bolt with a threaded connection. The magnetic field generator (4) includes a medium baffle (6), a strip yoke (7), a permanent magnet (8), a permanent magnet bracket (9), a base (10), a servo motor (11), a motor support (12), a drive wheel (13), a synchronous belt (14), a driven wheel (15), and a vertical bearing (16). The servo motor (11) is fixed to the base (10) through the motor support (12), and the drive wheel (13) and the servo motor (11) are connected by a coupling. The output shaft is fixedly connected, and the driving wheel (13) and the driven wheel (15) are connected by a synchronous belt (14). The output shaft of the driven wheel (15) is fixedly connected to a permanent magnet bracket (9) containing a permanent magnet (8). The two ends of the permanent magnet bracket (9) are mounted on vertical bearings (16) fixed on the base (10). The bar yoke (7) is fixed above the permanent magnet bracket (9) and forms an excitation air gap in a symmetrical manner. The medium baffle (6) is installed above the excitation air gap formed by the bar yoke (7). The output pulse of the servo motor (11) is controlled to drive the driving wheel (13) to drive the driven wheel (15) to rotate. The driven wheel (15) drives the permanent magnet (8) to rotate at a set angle, thereby adjusting the area of ​​magnetic flux between the permanent magnet (8) and the bar yoke (7), realizing precise control of the magnetic field strength of the polishing area, and promoting the renewal of abrasive grains during the polishing process, thus improving the polishing quality. When the magnetic poles of the permanent magnet (8) are arranged such that the S poles are opposite to the N poles, a closed magnetic circuit is generated at the excitation air gap, forming a strip-shaped high magnetic field region on the surface of the dielectric baffle (6); when the magnetic poles of the permanent magnet (8) are arranged such that the N poles are opposite to the N poles or the S poles are opposite to the S poles, a divergent magnetic circuit is generated at the excitation air gap, forming a strip-shaped near-zero magnetic field region on the surface of the dielectric baffle (6); as the permanent magnet (8) continues to rotate, the magnetic circuit at the excitation air gap alternately forms closed and divergent magnetic circuits, and similarly, a strip-shaped high magnetic field region and a near-zero magnetic field region alternately form on the surface of the dielectric baffle (6).

2. The polishing method of the magnetic shearing thickening polishing device based on the air gap excitation alternating magnetic field according to claim 1, characterized in that: The method is mainly implemented through the following steps: (1): Clamp the workpiece to be polished onto the workpiece fixture (3); (2): Based on the material, structural characteristics and processing requirements of the workpiece being polished, set the polishing trajectory of the six-degree-of-freedom industrial robot (1), the output pulse of the servo motor (11) and the feed speed of the precision displacement platform (5); (3): The magnetic shear thickening polishing medium is placed on the medium baffle (6) to form a "flexible contour particle cluster"; (4): Start the servo motor (11) to arrange the permanent magnets (8) at a set angle to form the required magnetic field strength at the excitation air gap; (5): Start the six-degree-of-freedom industrial robot (1) and the precision displacement platform (5) to control the relative motion between the magnetic shear thickening polishing medium and the workpiece to be polished. The magnetic shear thickening polishing medium changes from "flexible contour particle cluster" to "enhanced flexible contour particle cluster" to process the workpiece to be polished. (6): Start the servo motor (11) to gradually turn the arrangement of the permanent magnets (8) to N poles facing each other or S poles facing each other, so as to complete the renewal of abrasive particles during the polishing process. (7): After the abrasive particles are replaced, the arrangement of the permanent magnets (8) is turned to the set angle; (8): Repeat steps (5) to (7) until the processing requirements of the workpiece to be polished are met.

Images