Magnetic field assisted shear thickening and polishing device and method for fine structure surface

Abstract

The invention discloses a magnetic field auxiliary shear thickening polishing device and method for a fine structure surface. The device comprises a motion unit, a polishing unit, a clamping unit, a polishing solution circulating unit and a workbench. The polishing unit comprises a shear thickening polishing wheel and a magnetic polishing wheel. The double spindles are used for driving the magnetic polishing wheel and the shear thickening polishing wheel correspondingly, the material removal effect generated by the shear thickening effect of the shear thickening polishing wheel in the polishing process is weakened along with the increase of a gap between the shear thickening polishing wheel and the surface of a workpiece, and therefore in the fine structure polishing process with the large height difference, the material removal effect is reduced; the material removal effect at the bottom of the structure is weak, the magnetic polishing wheel is synchronously matched to drive the magnetic particles to perform composite shear thickening, the material removal effect at the bottom of the structure can be enhanced, balance of removal of the top and bottom materials of the fine structure is achieved, and therefore shape-preserving polishing of the surface of the fine structure is achieved. According to the invention, updating of the magnetic abrasive particles can be realized through intermittent magnetic field supply.

Description

Technical Field

[0001] The present invention belongs to the technical field of ultra-precision machining, and in particular relates to a magnetic field-assisted shear thickening polishing device and method for a microstructure surface. Background Art

[0002] With the continuous development of modern manufacturing technology, microstructured surfaces have been widely used in aerospace, semiconductors, precision optics, biomedicine and other fields. These microstructured surfaces usually have complex geometric shapes, and the requirements for surface accuracy and surface quality are extremely stringent. In particular, in the large-scale production of microstructured parts, compression molding or injection molding and other technologies are usually used to carry out batch manufacturing based on microstructured molds. Since parts manufacturing is based on the principle of replication, surface defects such as knife marks and burrs produced by microstructured molds after ultra-precision machining will be replicated on the surface of the component. Therefore, it is necessary to polish the microstructured molds and microstructured components after ultra-precision machining to improve the surface finish, reduce surface defects, and ensure the surface accuracy of the microstructure. Traditional polishing technology has been difficult to meet the requirements in some high-precision machining.

[0003] Chinese invention patent CN118809315A discloses a magnetic shear thickening polishing device and method based on an air gap excitation alternating magnetic field. This invention is a magnetic shear thickening polishing method based on a robot platform. The workpiece is clamped on the spindle at the end of the robot, and polishing is completed by high-speed rotation of the workpiece and contact with the magnetic shear thickening liquid. It is difficult to adapt to the complex conformal polishing requirements of the surface of the microstructure.

[0004] Chinese invention patent CN118456129A) discloses a multi-flexible magnetic shear thickening polishing method. The invention proposes a magnetic shear thickening polishing method based on an elastic matrix and a flexible fiber layer. This method is a contact polishing method in which the fiber layer of the elastic matrix tool contacts the workpiece surface and the effect of the magnetic abrasive is controlled by regulating the magnetic force distribution. The overall method is a contact polishing method, and the sharp corners of the microstructure are easily polished and blunted, which is not conducive to maintaining the polished surface shape of the microstructure.

[0005] Chinese invention patent CN115635367A discloses a tool polishing device and polishing method with magnetic field-assisted shear thickening. The invention uses high-speed rotation of the tool in the polishing cylinder to generate a certain shear rate in the gap between the tool and the polishing cylinder. The viscosity increases under the action of the magnetic field, thereby achieving the effect of flexible polishing and edge passivation by the high-speed rotation of the tool in the magnetic thickening fluid. However, it is difficult to achieve conformal polishing of the surface of fine structures.

[0006] Chinese invention patent CN115383610A discloses a constant-force non-contact polishing method and device for a microstructure profiling tool. The invention uses ultrasonic vibration to drive a single shear thickening liquid to produce a shear thickening effect. The designed profiling polishing tool achieves conformal polishing of the microstructure surface. However, the profiling tool is difficult to align, the shear thickening effect through ultrasonic excitation is weak, and the processing efficiency is low. Summary of the Invention

[0007] In order to solve the technical problem that traditional polishing technology and existing magnetic shear thickening polishing are difficult to apply to conformal polishing of microstructures, the present invention proposes a magnetic field assisted shear thickening polishing device and method for the surface of a microstructure, which can improve the surface quality of the microstructure surface while retaining the surface accuracy of the microstructure as much as possible.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] A magnetic field-assisted shear thickening polishing device for a microstructure surface comprises a motion unit, a polishing unit, a clamping unit, a polishing liquid circulation unit and a workbench. The motion unit is mounted on one side of the workbench, the clamping unit is mounted on the other side of the workbench, the polishing unit is mounted on the motion unit, and the polishing liquid circulation unit is mounted on the workbench.

[0010] The polishing unit includes a shear thickening polishing wheel and a magnetic polishing wheel, which are respectively installed side by side on the Z-axis slide through a shear thickening polishing wheel spindle and a magnetic polishing wheel spindle, and the shear thickening polishing wheel is located on one side of the microstructure surface of the workpiece, and the magnetic polishing wheel is located on the back side of the microstructure surface of the workpiece; the workpiece is installed on the clamping unit and the microstructure surface of the workpiece is perpendicular to the worktable plane.

[0011] Furthermore, the outer circumferential surface of the magnetic polishing wheel is uniformly inlaid with multiple magnetic poles along the circumferential direction; the magnetic poles are electromagnetic poles; and the polarities of adjacent magnetic poles are opposite.

[0012] Furthermore, a polishing pad is adhered to the surface of the shear thickening polishing wheel.

[0013] Furthermore, the axes of the shear thickening polishing wheel main shaft and the magnetic polishing wheel main shaft are located in a plane parallel to the workbench surface.

[0014] Furthermore, the motion unit includes an X-axis, a Y-axis, a Z-axis and a Z-axis slide. The X-axis is fixedly mounted on the workbench, the Y-axis is slidably connected to the X-axis and slides along the X-axis, the Z-axis is slidably connected to the Y-axis and slides along the Y-axis, and the Z-axis slide is slidably connected to the Z-axis and slides along the Z-axis; the motion unit provides the tool setting and relative motion required for polishing.

[0015] Furthermore, the clamping unit includes a clamp and a clamp platform, the clamp is fixedly mounted on the clamp platform, and the clamp platform is fixedly mounted on the workbench; the clamp platform is a U-shaped high-precision table, and the clamp clamps two opposite sides of the non-microstructure surface of the workpiece through two clamping blocks.

[0016] Furthermore, the polishing liquid circulation unit includes a polishing liquid tank, a circulation pump, a polishing liquid supply pipe and a pipe fixing plate. The circulation pump is fixed under the workbench surface, and the pipe fixing plate is fixed on the main shaft of the shear thickening polishing wheel; the polishing liquid tank is fixed under the workbench surface and is located directly below the fixture platform, and the upper opening of the polishing liquid tank is connected to the lower opening of the fixture platform; one end of the polishing liquid supply pipe is connected to the outlet of the circulation pump, and the other end passes through the pipe fixing plate and is aligned with the polishing area of ​​the workpiece; the inlet of the circulation pump is connected to the polishing liquid tank through a pipe; the circulation pump is connected to the circulation pump motor, and the circulation pump motor is fixed on the workbench.

[0017] Furthermore, the polishing liquid tank is in the shape of a rectangular funnel, and a stirrer is provided in the polishing liquid tank.

[0018] Furthermore, the microstructure of the workpiece includes a rectangular microstructure, a V-groove microstructure, a microlens array microstructure and a cylindrical microstructure.

[0019] A magnetic field-assisted shear thickening polishing method for a microstructured surface, comprising the following steps:

[0020] Step 1: Install the shear thickening polishing wheel and the magnetic polishing wheel on the shear thickening polishing wheel main shaft and the magnetic polishing wheel main shaft respectively;

[0021] Step 2: Mount the workpiece on the fixture platform through the fixture, adjust it to a suitable position and clamp it;

[0022] Step 3: Controlling the motion platform to move to a specified position through a controller, adjusting the gap between the shear thickening polishing wheel and the microstructure surface of the workpiece, and adjusting the gap between the magnetic polishing wheel and the back of the workpiece;

[0023] Step 4: Add polishing liquid into the polishing liquid tank, start the two polishing spindle motors, the circulating pump motor and the agitator;

[0024] Step 5: Calculate the Z-axis motion range based on the size of the polishing area on the microstructure surface of the workpiece, start the Z-axis reciprocating motion, and intermittently power the electromagnetic poles of the magnetic polishing wheel according to a prescribed rule.

[0025] Step 6: After polishing is completed, turn off the polishing spindle motor, circulation pump motor, agitator and Z-axis motion motor, and remove the workpiece for cleaning and inspection.

[0026] Furthermore, in step three, the gap between the shear thickening polishing wheel and the microstructure surface of the workpiece is 0.1-0.3 mm, and the gap between the magnetic polishing wheel and the back surface of the workpiece is 1-10 mm.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention utilizes dual spindles to drive the magnetic polishing wheel and the shear thickening polishing wheel respectively. During the polishing process, the material removal effect generated by the shear thickening effect of the shear thickening polishing wheel weakens as the gap between the shear thickening polishing wheel and the workpiece surface increases. This results in a weaker material removal effect at the bottom of the structure during the polishing of microstructures with large height differences. The synchronous cooperation of the magnetic polishing wheel to drive the composite shear thickening effect of the magnetic particles can enhance the material removal effect at the bottom of the structure, achieve a balance in material removal at the top and bottom of the microstructure, and thus achieve conformal polishing of the microstructure surface.

[0029] 2. The magnetic field supply of the magnetic polishing wheel of the present invention is intermittent, and the renewal of magnetic abrasive particles can be achieved through the intermittent magnetic field supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the device of the present invention.

[0031] Figure 2 Schematic diagram of the polishing unit of the present invention.

[0032] Figure 3 Schematic diagram of the clamp unit of the present invention.

[0033] Figure 4 Schematic diagram of the polishing liquid circulation unit of the present invention.

[0034] Figure 5 Schematic diagram of the rectangular microstructure surface shape of the workpiece.

[0035] Figure 6 Schematic diagram of the surface shape of the V-groove microstructure of the workpiece.

[0036] Figure 7 Schematic diagram of the microstructure shape of the microlens array of the workpiece.

[0037] Figure 8 Schematic diagram of the surface shape of the cylindrical microstructure of the workpiece.

[0038] In the figure: 1. Polishing liquid supply pipe; 2. Circulation pump; 3. Circulation pump motor; 4. Fixture platform; 5. Fixture; 6. Clamping block, 7. Shear thickening polishing wheel; 8. Magnetic polishing wheel; 9. Workpiece; 10. Shear thickening polishing wheel spindle; 11. Magnetic polishing wheel spindle; 12. Pipe fixing plate; 13. Z-axis slide; 14. Z-axis; 15. X-axis; 16. Y-axis; 17. Workbench; 18. Polishing pad, 19. Microstructure surface, 20. Magnetic pole; 21. Polishing liquid tank. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings. Figure 1-8 As shown, a magnetic field-assisted shear thickening polishing device for a microstructure surface includes a moving unit, a polishing unit, a clamping unit, a polishing liquid circulation unit and a workbench 17. The moving unit is installed on one side of the workbench 17, the clamping unit is installed on the other side of the workbench 17, the polishing unit is installed on the moving unit, and the polishing liquid circulation unit is installed on the workbench 17.

[0040] The polishing unit includes a shear thickening polishing wheel 7 and a magnetic polishing wheel 8, which are respectively installed side by side on the Z-axis slide 13 through a shear thickening polishing wheel spindle 10 and a magnetic polishing wheel spindle 11, and the shear thickening polishing wheel 7 is located on one side of the microstructure surface 19 of the workpiece 9, and the magnetic polishing wheel 8 is located on the back side of the microstructure surface 19 of the workpiece 9; the workpiece 9 is installed on the clamping unit and the microstructure surface 19 of the workpiece 9 is perpendicular to the plane of the workbench 17.

[0041] Furthermore, the outer circumferential surface of the magnetic polishing wheel 8 is uniformly inlaid with multiple magnetic poles 20 along the circumferential direction; the magnetic poles 20 are electromagnetic poles; and the polarities of adjacent magnetic poles 20 are opposite.

[0042] Furthermore, a polishing pad 18 is adhered to the surface of the shear thickening polishing wheel 7 .

[0043] Furthermore, the axes of the shear thickening polishing wheel spindle 10 and the magnetic polishing wheel spindle 11 are located in a plane parallel to the surface of the workbench 17 .

[0044] Furthermore, the motion unit includes an X-axis 15, a Y-axis 16, a Z-axis 14 and a Z-axis slide 13, the X-axis 15 is fixedly mounted on a workbench 17, the Y-axis 16 is slidably connected to the X-axis 15 and slides along the X-axis 15, the Z-axis 14 is slidably connected to the Y-axis 16 and slides along the Y-axis 16, and the Z-axis slide 13 is slidably connected to the Z-axis 14 and slides along the Z-axis 14; the motion unit provides the tool setting and relative motion required for polishing.

[0045] Furthermore, the clamping unit includes a clamp 5 and a clamp platform 4, the clamp 5 is fixedly mounted on the clamp platform 4, and the clamp platform 4 is fixedly mounted on the workbench 17; the clamp platform 4 is a U-shaped high-precision table, and the clamp 5 clamps two opposite sides of the non-microstructure surface 19 of the workpiece 9 through two clamping blocks 6.

[0046] Furthermore, the polishing liquid circulation unit includes a polishing liquid tank 21, a circulation pump 2, a polishing liquid supply pipe 1 and a pipe fixing plate 12, the circulation pump 2 is fixed below the workbench 17, and the pipe fixing plate 12 is fixed on the shear thickening polishing wheel spindle 10; the polishing liquid tank 21 is fixed below the workbench 17 and is located directly below the fixture platform 4, and the upper opening of the polishing liquid tank 21 is docked with the lower opening of the fixture platform 4; one end of the polishing liquid supply pipe 1 is connected to the outlet of the circulation pump 2, and the other end passes through the pipe fixing plate 12 to be aligned with the polishing area of ​​the workpiece 9; the inlet of the circulation pump 2 is connected to the polishing liquid tank 21 through a pipe; the circulation pump 2 is connected to the circulation pump motor 3, and the circulation pump motor 3 is fixed on the workbench 17.

[0047] Furthermore, the polishing liquid tank 21 is in the shape of a rectangular funnel, and a stirrer (not shown) is provided in the polishing liquid tank 21 .

[0048] Furthermore, the microstructure of the workpiece 9 includes a rectangular microstructure, a V-groove microstructure, a microlens array microstructure and a cylindrical microstructure.

[0049] The working principle of the present invention is as follows:

[0050] The polishing unit consists of two coaxially aligned spindle-driven polishing wheels, each capable of independently controlled polishing speed. A shear-thickening polishing wheel 7 is positioned on the side of the workpiece 9 with a microstructured surface 19, while a magnetic polishing wheel 8 is positioned on the other side. Magnetic polishing wheel 8 is inlaid with magnetic poles 20, which can be arranged as desired to control the magnetic particles in the magnetic shear-thickening polishing fluid. A polishing pad 18 is attached to the surface of shear-thickening polishing wheel 7, which drives the shear-thickening polishing fluid onto the workpiece 9 surface to produce a shear-thickening effect.

[0051] During polishing, the polishing liquid circulation unit sprays shear thickening polishing liquid onto the surface to be polished of the workpiece 9. The shear thickening polishing wheel 7 rotates at high speed, causing the polishing liquid to form "particle clusters" through shear thickening, thereby enhancing the binding force of the abrasive particles in the polishing liquid and forming a "flexible fixed abrasive tool" at the processing position. At the same time, the magnetic field of the magnetic polishing wheel 8 acts on the magnetic substance in the polishing liquid, thereby enhancing the adhesion of the polishing liquid to the surface of the workpiece 9. The combination of the two improves the polishing ability of fine structures at different depths.

[0052] The polishing liquid tank 21 is funnel-shaped and contains the magnetic shear thickening polishing liquid required for polishing. The stirrer continuously stirs to prevent the polishing liquid from stratifying. The circulating pump 2 is connected to the bottom of the polishing liquid tank 21 and is powered by the circulating pump motor 3. The circulating pump 2 draws polishing liquid from the polishing liquid tank 21 and sprays it onto the polishing area of ​​the workpiece 9 through the polishing liquid supply pipe 1. The end of the polishing liquid supply pipe 1 passes through the pipe fixing plate 12 installed on the shear thickening polishing wheel spindle 10 and is fixed in position by the pipe fixing plate 12 to ensure that the outlet is always aligned with the polishing area. After polishing, the magnetic shear thickening polishing liquid flows into the polishing liquid tank 21.

[0053] A magnetic field-assisted shear thickening conformal polishing method for a microstructured surface, comprising the following steps:

[0054] Step 1: Install the shear thickening polishing wheel 7 and the magnetic polishing wheel 8 on the shear thickening polishing wheel main shaft 10 and the magnetic polishing wheel main shaft 11 respectively;

[0055] Step 2: Install the workpiece 9 on the fixture platform 4 through the fixture 5, adjust it to a suitable position and clamp it;

[0056] Step 3: Control the motion platform to move to a specified position through the controller, adjust the gap between the shear thickening polishing wheel 7 and the microstructure surface 19 of the workpiece 9, and adjust the gap between the magnetic polishing wheel 8 and the back of the workpiece 9;

[0057] Step 4: Add the polishing liquid into the polishing liquid tank 21, and start the two polishing spindle motors, the circulating pump motor 3 and the agitator;

[0058] Step 5: Calculate the motion range of the Z-axis 14 according to the polishing area size of the microstructure surface 19 of the workpiece 9, start the reciprocating motion of the Z-axis 14, and intermittently power the electromagnetic poles of the magnetic polishing wheel 8 according to the prescribed rules.

[0059] Step 6: After polishing is completed, turn off the polishing spindle motor, circulation pump motor 3, stirrer and Z-axis 14 motion motor, and remove the workpiece 9 for cleaning and inspection.

[0060] Furthermore, in step three, the gap between the shear thickening polishing wheel 7 and the microstructure surface 19 of the workpiece 9 is 0.1-0.3 mm, and the gap between the magnetic polishing wheel 8 and the back surface of the workpiece 9 is 1-10 mm.

[0061] The present invention is not limited to this embodiment, and any equivalent concepts or modifications within the technical scope disclosed by the present invention are included in the protection scope of the present invention.

Claims

1. A magnetic field-assisted shear thickening polishing device for a microstructure surface, comprising a motion unit, a polishing unit, a clamping unit, a polishing liquid circulation unit, and a workbench (17), wherein the motion unit is mounted on one side of the workbench (17), the clamping unit is mounted on the other side of the workbench (17), the polishing unit is mounted on the motion unit, and the polishing liquid circulation unit is mounted on the workbench (17); Its characteristics are: The polishing unit comprises a shear thickening polishing wheel (7) and a magnetic polishing wheel (8), wherein the shear thickening polishing wheel (7) and the magnetic polishing wheel (8) are respectively mounted side by side on a Z-axis slide (13) via a shear thickening polishing wheel spindle (10) and a magnetic polishing wheel spindle (11), and the shear thickening polishing wheel (7) is located on one side of a microstructure surface (19) of a workpiece (9), and the magnetic polishing wheel (8) is located on the back side of the microstructure surface (19) of the workpiece (9); the workpiece (9) is mounted on the clamping unit, and the microstructure surface (19) of the workpiece (9) is perpendicular to the plane of the worktable (17).

2. The magnetic field-assisted shear thickening polishing device for a microstructured surface according to claim 1, characterized in that: The outer circumferential surface of the magnetic polishing wheel (8) is uniformly inlaid with a plurality of magnetic poles (20) along the circumferential direction; the magnetic poles (20) are electromagnetic poles; the polarities of adjacent magnetic poles (20) are opposite; and a polishing pad (18) is adhered to the surface of the shear thickening polishing wheel (7).

3. The magnetic field-assisted shear thickening polishing device for a microstructured surface according to claim 1, characterized in that: The axes of the shear thickening polishing wheel main shaft (10) and the magnetic polishing wheel main shaft (11) are located in a plane parallel to the surface of the workbench (17).

4. The magnetic field-assisted shear thickening polishing device for a microstructured surface according to claim 1, characterized in that: The motion unit comprises an X-axis (15), a Y-axis (16), a Z-axis (14) and a Z-axis slide (13); the X-axis (15) is fixedly mounted on a workbench (17); the Y-axis (16) is slidably connected to the X-axis (15) and slides along the X-axis (15); the Z-axis (14) is slidably connected to the Y-axis (16) and slides along the Y-axis (16); the Z-axis slide (13) is slidably connected to the Z-axis (14) and slides along the Z-axis (14); and the motion unit provides tool setting and relative motion required for polishing.

5. The magnetic field-assisted shear thickening polishing device for a microstructured surface according to claim 1, characterized in that: The clamping unit comprises a clamp (5) and a clamp platform (4), wherein the clamp (5) is fixedly mounted on the clamp platform (4), and the clamp platform (4) is fixedly mounted on a workbench (17); the clamp platform (4) is a high-precision U-shaped platform, and the clamp (5) clamps two opposite sides of a non-microstructure surface (19) of a workpiece (9) through two clamping blocks (6).

6. The magnetic field-assisted shear thickening polishing device for a microstructured surface according to claim 1, characterized in that: The polishing liquid circulation unit comprises a polishing liquid tank (21), a circulation pump (2), a polishing liquid supply pipe (1) and a pipe fixing plate (12), wherein the circulation pump (2) is fixed below the workbench (17) table, and the pipe fixing plate (12) is fixed on the shear thickening polishing wheel spindle (10); the polishing liquid tank (21) is fixed below the workbench (17) table and is located directly below the fixture platform (4), and the upper opening of the polishing liquid tank (21) is docked with the lower opening of the fixture platform (4); one end of the polishing liquid supply pipe (1) is connected to the outlet of the circulation pump (2), and the other end passes through the pipe fixing plate (12) and is aligned with the polishing area of ​​the workpiece (9); the inlet of the circulation pump (2) is connected to the polishing liquid tank (21) through a pipe; the circulation pump (2) is connected to the circulation pump motor (3), and the circulation pump motor (3) is fixed on the workbench (17).

7. The magnetic field-assisted shear thickening polishing device for a microstructured surface according to claim 1, characterized in that: The polishing liquid box (21) is in the shape of a rectangular funnel, and a stirrer is arranged in the polishing liquid box (21).

8. The magnetic field-assisted shear thickening polishing device for a microstructured surface according to claim 1, characterized in that: The microstructure of the workpiece (9) includes a rectangular microstructure, a V-groove microstructure, a microlens array microstructure and a cylindrical microstructure.

9. A method for polishing a microstructured surface by magnetic field-assisted shear thickening, comprising polishing the surface by using the magnetic field-assisted shear thickening polishing device for a microstructured surface according to any one of claims 1 to 8, comprising the following steps: Step 1: installing a shear thickening polishing wheel (7) and a magnetic polishing wheel (8) on a shear thickening polishing wheel main shaft (10) and a magnetic polishing wheel main shaft (11) respectively; Step 2: Mount the workpiece (9) on the fixture platform (4) through the fixture (5), adjust it to a suitable position and clamp it; Step 3, controlling the motion platform to move to a specified position through a controller, adjusting the gap between the shear thickening polishing wheel (7) and the microstructure surface (19) of the workpiece (9), and adjusting the gap between the magnetic polishing wheel (8) and the back of the workpiece (9); Step 4: Add the polishing liquid into the polishing liquid tank (21), start the two polishing spindle motors, the circulating pump motor (3) and the agitator; Step 5, calculating the motion range of the Z-axis (14) according to the polishing area size of the microstructure surface (19) of the workpiece (9), starting the reciprocating motion of the Z-axis (14), and intermittently powering the magnetic pole (20) of the magnetic polishing wheel (8) according to a prescribed rule; Step 6: After polishing is completed, the polishing spindle motor, the circulating pump motor (3), the stirrer and the Z-axis (14) motion motor are turned off, and the workpiece (9) is removed for cleaning and inspection.

10. The magnetic field-assisted shear thickening polishing method for a microstructured surface according to claim 9, characterized in that: In step 3, the gap between the shear thickening polishing wheel (7) and the microstructure surface (19) of the workpiece (9) is 0.1-0.3 mm, and the gap between the magnetic polishing wheel (8) and the back surface of the workpiece (9) is 1-10 mm.

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