Micro-groove network structure ball head reshaping device and method based on magnetic field enhanced force rheology

Abstract

The application discloses a micro-groove network structure ball head dressing device and method based on magnetic field enhanced force rheology, wherein the dressing device comprises a polishing tank containing polishing liquid, a jig is arranged in the polishing tank, a workpiece is fixed in the polishing tank by the jig and is immersed in the polishing liquid, and the dressing device further comprises a magnetic ball head connected with a driving device through a rod. The dressing method is applied to the dressing device and comprises the following steps: fixing the workpiece; setting a ball center of the ball head on a rotary center line of the workpiece, adjusting an oblique plane of the rod relative to a tangent plane of a concave surface of the workpiece, and forming the same gap between the ball head and the workpiece at different positions of the concave surface; preparing the polishing liquid and pouring the polishing liquid into the polishing tank until the workpiece to be processed is immersed; and driving the ball head to feed and process by the driving device, so that the polishing medium in the polishing gap generates local thickening and solidification and other rheological effects, under the action of flow pressure effect, "particle cluster" containing abrasive grains micro-cut the surface of the workpiece, the surface material of the workpiece is removed, and then the dressing is realized.

Description

Technical Field

[0001] This invention relates to the field of ultra-precision shaping technology, and in particular to a microgroove network structure ball head shaping device and method based on magnetic field-enhanced force rheology. Background Technology

[0002] Small-diameter aspherical parts with ultra-smooth surfaces, high surface accuracy, and low / zero subsurface damage play a crucial role in the rapid development of industries such as optoelectronic communications, defense, biomedicine, and aerospace. These parts require ultra-precision polishing to meet industry requirements for sub-micron shape accuracy, nanometer-level surface roughness, and extremely low subsurface damage. Existing mature ultra-precision deterministic polishing technologies include single-point diamond turning, ultra-precision grinding with grinding wheels, airbag polishing, magnetorheological polishing, airbag-shear thickening synergistic polishing, and chemical-shear thickening synergistic polishing. While single-point diamond turning and ultra-precision grinding with abrasive wheels can achieve high surface accuracy and high processing efficiency for curved workpieces, the workpiece surface not only retains regular grinding marks but also inevitably produces various processing defects such as lattice dislocations, cracks, residual stress, work hardening, and edge chipping. Airbag polishing has advantages such as high polishing efficiency and adaptability to curved surface shapes, but it also has problems such as unpredictable polishing morphology, easy damage to polishing tools, subsurface damage, and high equipment precision requirements. Magnetorheological polishing has advantages such as stable removal function, no subsurface damage, and no grinding head damage, but existing polishing slurries are expensive and have poor settling properties. The complexity and high manufacturing cost of existing polishing systems, coupled with their inability to process small-diameter concave workpieces, are key factors limiting their practical industrial application. Airbag-shear thickening polishing utilizes non-Newtonian fluid polishing slurries to dynamically deform the polishing tool during processing, achieving self-adjustment of material removal depth. While the polishing slurry is environmentally friendly, it also presents technical challenges such as unpredictable polishing morphology and low processing efficiency for ceramic materials. Chemical-shear thickening synergistic polishing can achieve deterministic polishing of curved workpieces, offering advantages such as controllable polishing shape and high surface precision. However, it suffers from environmental pollution from the polishing slurry and low processing efficiency. Clearly, existing technologies have significant limitations. Therefore, there is an urgent need for a highly efficient, high-precision, low-damage, and low-cost shaping device and method for small-diameter aspherical parts. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a device and method for shaping a ball head of a microgroove network structure based on magnetic field-enhanced force rheology.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A microgroove network structure ball head shaping device based on magnetic field-enhanced force rheology includes a polishing tank filled with polishing fluid, a fixture inside the polishing tank, and a workpiece fixed in the polishing tank by the fixture and immersed in the polishing fluid. The shaping device also includes a magnetic polishing ball head located inside the polishing tank and above the workpiece, the ball head being connected to a driving device via a rod. The ball head is made of permanent magnet material, and the polishing tank, fixture, and rod are all made of non-magnetic material.

[0006] The polishing fluid is configured as a starch solution containing 3%-12% carbonyl iron powder particles, 10%-28% abrasive particles, and 0.5%-5% polyethylene glycol by mass; the starch solution is prepared by mixing starch particles and deionized water at a mass ratio of 1:1 and then mechanically stirring.

[0007] The ball head surface is formed with a grid groove, and the width to depth ratio of the grid groove is 1:2.

[0008] The ball head surface is coated.

[0009] The magnetic field strength on the surface of the ball head is 50-250 mT, and the magnetic induction intensity on the surface of the workpiece is 10-150 mT.

[0010] Then, this invention discloses a method for shaping the ball head of a microgroove network structure based on magnetic field-enhanced force rheology. The shaping method is applied to the above-mentioned shaping device and includes the following steps:

[0011] Step S1: Fix the workpiece using a fixture;

[0012] Step S2: Set the center of the ball head on the rotation center line of the workpiece, and adjust the inclination of the rod relative to the tangent plane of the concave surface of the workpiece, so that the ball head and the workpiece form the same gap at different positions on the concave surface.

[0013] Step S3: Prepare polishing slurry and pour the polishing slurry into the polishing tank until the workpiece is submerged;

[0014] In step S4, the drive device drives the ball head to feed and process according to the dwell time parameters and polishing path parameters via the rod.

[0015] Step S3 includes:

[0016] Step S31: Under normal temperature conditions, starch granules and deionized water are mixed at a mass ratio of 1:1 and mechanically stirred to obtain a shear thickening liquid.

[0017] In step S32, carbonyl iron powder particles with a mass fraction of 3%-12%, abrasive particles of 10%-28%, and polyethylene glycol of 0.5%-5% are added to the shear thickening liquid, and the mixture is stirred and ultrasonically dispersed until homogeneous.

[0018] Step S4 includes:

[0019] Step S41: Measure the surface shape error of the workpiece using a PGI profilometer, and calculate the dwell time parameter accordingly.

[0020] Step S42: Generate spiral polishing path parameters based on the concave geometric model of the workpiece;

[0021] Step S43: Import the residence time parameters and polishing path parameters into the drive device.

[0022] The ball head feeds along the meridian of the rotating workpiece surface toward the edge.

[0023] The gap between the ball head and the workpiece is 0.1-0.8mm, and the ball head rotation speed range is 100-5000rpm.

[0024] Compared with the prior art, the advantages of the present invention are as follows:

[0025] The installed polishing tank can be used to hold polishing fluid containing abrasive particles of hydroxyl iron powder. When the ball head starts to rotate, it causes the polishing medium in the polishing gap to produce local thickening and solidification rheological effects. Under the action of flow pressure effect, the "particle cluster" containing abrasive particles micro-cuts the surface of the workpiece, causing the removal of surface material and thus achieving reshaping. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the shaping device;

[0027] Figure 2 This is a structural diagram of the ball head and the rod;

[0028] Figure 3 This is a schematic diagram of the magnetic field distribution at the spherical head;

[0029] Figure 4 This is a before-and-after comparison diagram of the workpiece before and after polishing;

[0030] Figure 5 This is a flowchart illustrating the reshaping method.

[0031] The labels in the diagram represent: 1. Polishing groove; 2. Fixture; 3. Workpiece; 4. Ball head; 41. Mesh groove; 5. Rod; 6. Drive device. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] like Figures 1 to 4As shown, in this embodiment, the microgroove network structure ball head shaping device based on magnetic field-enhanced force rheology includes a polishing tank 1 containing polishing fluid, a fixture 2 inside the polishing tank 1, and a workpiece 3 fixed in the polishing tank 1 by the fixture 2 and immersed in the polishing fluid. The shaping device also includes a magnetic polishing ball head 4 located inside the polishing tank 1 and above the workpiece 3. The ball head 4 is connected to the driving device 6 via a rod 5. The ball head 4 is made of permanent magnet material, and the polishing tank 1, fixture 2, and rod 5 are all made of non-magnetic stainless steel. Based on the coupling effect of magnetic force and high shear stress, the polishing medium in the polishing gap produces local thickening and solidification rheological effects. The magnetic field enhances the thickening effect, and under the action of the flow pressure effect of the fluid in the wedge region, the "particle cluster" containing abrasive particles scratches and micro-cuts the surface of the workpiece 3, resulting in material removal from the surface of the workpiece 3 and achieving shaping. The polishing tank 1 contains polishing fluid containing hydroxyl iron powder and abrasive particles. During polishing, the ball head 4 rotates, and under the action of magnetic field force and high shear stress, the polishing fluid between the workpiece 3 surface and the ball head 4 undergoes local thickening, solidification, and other rheological effects, and a flow pressure effect is generated in the wedge-shaped area. The "particle clusters" in the polishing fluid scratch and micro-cut the surface of the workpiece 3, causing material removal from the surface of the workpiece 3, thereby achieving reshaping. The workpiece 3 is a small-diameter rotating aspherical hard and brittle ceramic mold, which belongs to the category of optical component molds. It is a non-magnetic and difficult-to-machine material and will not be magnetized by a magnetic field. Therefore, its surface will not adsorb carbonyl iron powder particles from the polishing fluid due to the magnetic field. The ball head 4 is made of permanent magnet material. The polishing tank 1, fixture 2, and rod 5 can be made of stainless steel. Non-magnetic materials can avoid affecting the magnitude and uniformity of the magnetic field in the polishing area, thereby ensuring that the components in the polishing fluid are evenly distributed and that the rheological properties are stable. The ball head 4 is a neodymium iron boron permanent magnet instead of an electromagnet, thus preventing changes in the rheological properties of the polishing fluid due to excessive heat generation, ensuring stable material removal, and eliminating safety hazards. Compared to existing technologies, the shaping device disclosed in this invention has a simple structure, long service life, high positioning accuracy, and convenient installation and disassembly. Processing parameters can be changed according to shaping requirements, achieving controllability and adaptability. Furthermore, by employing a flexible method to correct the surface shape of small-diameter rotating aspherical workpieces, it achieves zero or low-damage and high-precision polishing of their surfaces. The rheological properties of the polishing fluid are not altered due to excessive heat generation during the shaping process, ensuring stable material removal and eliminating safety hazards.

[0034] In this embodiment, the polishing slurry is configured as a starch solution containing 3%-12% carbonyl iron powder particles, 10%-28% abrasive particles, and 0.5%-5% polyethylene glycol by mass. The starch solution is prepared by mixing starch particles and deionized water in a 1:1 mass ratio and then mechanically stirring. Polyethylene glycol has water solubility and dispersibility, which can not only inhibit excessive particle aggregation but also form micron-sized water clusters with abrasive particles, resulting in a more uniform distribution of abrasive particles in the polishing slurry.

[0035] In this embodiment, the surface of the ball head 4 is formed with a grid groove 41, the width to depth ratio of the grid groove 41 is 1:2. By setting the grid groove 41 on the surface of the ball head 4, not only can a "peak effect" be generated to enhance the magnetic induction intensity of the ball head 4 surface, and the polishing fluid is prompted to form a series of flexible small grinding heads on the grid groove 41, there is almost no centrifugal and hydroplaning effect under high-speed polishing, thereby significantly improving the material removal capacity; at the same time, it can also enhance the friction between the polishing fluid and the surface of the ball head 4, thereby reducing the centrifugal effect when the ball head 4 rotates at high speed, further improving the material removal rate. Specifically, the grid groove 41 is arranged on the outer periphery of the ball head 4 where it is tangent to the curved surface of the workpiece 3. Due to the peak effect, the magnetic field intensity on the outer side increases, which can compensate for the small material removal force caused by the low flow pressure on the outer side, so that the material removal contour changes from a teardrop shape to an ellipse, reducing the residual height of the workpiece 3 surface after polishing, making the material removal on the surface of the workpiece 3 uniform, and improving the polishing quality and polishing efficiency.

[0036] In this embodiment, the surface of the ball head 4 is coated. The magnetic field strength on the surface of the ball head 4 is 50-250 mT, and the magnetic induction intensity on the surface of the workpiece 3 is 10-150 mT. By coating the surface of the ball head 4, oxidation can be prevented, thereby extending its service life. The ball head 4 is magnetized along the length of the rod 5, so that its surface magnetic field strength is 50-250 mT. Within the magnetic field range of the ball head 4, the magnetic induction intensity on the surface of the workpiece 3 is 10-150 mT. The surface of the workpiece 3 is always under weak magnetic induction conditions. Under this magnetic field environment, the polishing fluid not only has strong shear stress, but also maintains good flow characteristics for circulation. Specifically, the diameter of the ball head is... The workpiece is 5mm thick, and a silicon carbide mold with a diameter of φ10mm is used. The grid groove 41 is formed by laser scanning ablation, and has a maze texture, with the groove depth increasing from the outside to the inside.

[0037] Specifically, the diameter of the ball head is The workpiece is 5mm thick, and a silicon carbide mold with a diameter of φ10mm is used. The grid groove 41 is formed by laser scanning ablation, and has a maze texture, with the groove depth increasing from the outside to the inside.

[0038] like Figure 5 As shown, the present invention also discloses a method for shaping the ball head of a microgroove network structure based on magnetic field-enhanced force rheology. In one embodiment, the shaping method is applied to the above-mentioned shaping device and includes the following steps:

[0039] Step S1: Fix the workpiece 3 using the fixture 2;

[0040] Step S2: Set the center of the ball head 4 on the rotation center line of the workpiece 3, and adjust the inclination of the rod 5 relative to the tangent plane of the concave surface of the workpiece 3, so that the ball head 4 and the workpiece 3 form the same gap at different positions on the concave surface.

[0041] Step S3: Prepare polishing liquid and pour it into polishing tank 1 until the workpiece 3 is submerged;

[0042] In step S4, the drive device 6 drives the ball head to feed and process via the rod 5 according to the dwell time parameters and polishing path parameters.

[0043] Among them, a CCD industrial camera is used to observe and locate the center of the ball head 4, so that it is on the rotation center line of the workpiece 3.

[0044] Step S3 specifically includes:

[0045] Step S31: Under normal temperature conditions, starch granules and deionized water are mixed at a mass ratio of 1:1 and mechanically stirred to obtain a shear thickening liquid.

[0046] In step S32, 5% carbonyl iron powder particles, 12% abrasive particles and 2% polyethylene glycol by mass are added to the shear thickening liquid, and the mixture is stirred and ultrasonically dispersed until uniform.

[0047] Step S4 specifically includes:

[0048] Step S41: Measure the surface shape error of workpiece 3 using a PGI profilometer, and calculate the dwell time parameter accordingly.

[0049] Step S42: Generate spiral polishing path parameters based on the concave geometric model of workpiece 3;

[0050] Step S43: Import the residence time parameters and polishing path parameters into the drive unit 6.

[0051] In this embodiment, the ball head 4 feeds along the meridian of the curved surface of the rotating workpiece 3 toward the edge position for machining.

[0052] In this embodiment, the gap between the ball head 4 and the workpiece 3 is 0.1mm, and the rotation speed of the ball head 4 is set to 3000rpm.

[0053] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. A microgroove network structure ball-shaped shaping device based on magnetic field-enhanced force rheology, characterized in that: The device includes a polishing tank (1) containing polishing liquid, a fixture (2) is provided in the polishing tank (1), and the workpiece (3) is fixed in the polishing tank (1) by the fixture (2) and immersed in the polishing liquid; the shaping device also includes a magnetic polishing ball head (4) located in the polishing tank (1) and above the workpiece (3), the ball head (4) is connected to the driving device (6) via a rod (5); the ball head (4) is made of permanent magnet material, and the polishing tank (1), fixture (2) and rod (5) are all made of non-magnetic material; the surface of the ball head (4) is partially formed with a grid groove (41); the center of the ball head (4) is set on the rotation center line of the workpiece (3), and the rod (5) is adjusted to be inclined relative to the tangent plane of the concave surface of the workpiece (3), the grid groove (41) is arranged on the outer periphery of the ball head (4) tangent to the curved surface of the workpiece (3), and the ball head (4) and the workpiece (3) form the same gap at different positions on the concave surface.

2. The microgroove network structure ball-shaped device based on magnetic field-enhanced force rheology according to claim 1, characterized in that: The polishing fluid is configured as a starch solution containing 3%-12% carbonyl iron powder particles, 10%-28% abrasive particles, and 0.5%-5% polyethylene glycol by mass; the starch solution is prepared by mixing starch particles and deionized water at a mass ratio of 1:1 and then mechanically stirring.

3. The microgroove network structure ball-shaped device based on magnetic field-enhanced force rheology according to claim 1, characterized in that: The width to depth ratio of the grid groove (41) is 1:

2.

4. The microgroove network structure ball-shaped device based on magnetic field-enhanced force rheology according to claim 1, characterized in that: The ball head (4) has a coating on its surface.

5. The microgroove network structure ball-shaped device based on magnetic field-enhanced force rheology according to claim 1, characterized in that: The magnetic field strength on the surface of the ball head (4) is 50-250mT, and the magnetic induction strength on the surface of the workpiece (3) is 10-150mT.

6. A method for shaping the spherical head of a microgroove network structure based on magnetic field-enhanced force rheology, characterized in that: Using the shaping device according to any one of claims 1-5 includes the following steps: Step S1, use the fixture (2) to fix the workpiece (3); Step S2, set the center of the ball head (4) on the rotation center line of the workpiece (3), and adjust the bar (5) to be inclined relative to the tangent plane of the concave surface of the workpiece (3), and form the same gap between the ball head (4) and the workpiece (3) at different positions on the concave surface. Step S3: Prepare polishing liquid and pour the polishing liquid into the polishing tank (1) until the workpiece (3) is submerged; In step S4, the drive device (6) drives the ball head to feed and process via the rod (5) according to the dwell time parameters and polishing path parameters.

7. The method for shaping the spherical head of a microgroove network structure based on magnetic field-enhanced force rheology according to claim 6, characterized in that: Step S3 includes: Step S31: Under normal temperature conditions, starch granules and deionized water are mixed at a mass ratio of 1:1 and mechanically stirred to obtain a shear thickening liquid. In step S32, carbonyl iron powder particles with a mass fraction of 3%-12%, abrasive particles of 10%-28%, and polyethylene glycol of 0.5%-5% are added to the shear thickening liquid, and the mixture is stirred and ultrasonically dispersed until homogeneous.

8. The method for shaping the spherical head of a microgroove network structure based on magnetic field-enhanced force rheology according to claim 6, characterized in that: Step S4 includes: Step S41: Measure the surface shape error of the workpiece (3) using a PGI profiler and calculate the dwell time parameter accordingly; Step S42: Generate spiral polishing path parameters based on the concave geometric model of the workpiece (3); Step S43: Import the residence time parameters and polishing path parameters into the drive device (6).

9. The method for shaping the spherical head of a microgroove network structure based on magnetic field-enhanced force rheology according to claim 6, characterized in that: The ball head (4) feeds along the meridian of the surface of the rotating workpiece (3) toward the edge position.

10. The method for shaping the spherical head of a microgroove network structure based on magnetic field-enhanced force rheology according to claim 6, characterized in that: The gap between the ball head (4) and the workpiece (3) is 0.1-0.8mm, and the rotation speed of the ball head (4) is 100-5000rpm.

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