Method and device for manufacturing by air pressure simulation mode ultrasonic assisted core-shell abrasive magnetic rheological composite polishing

Abstract

The application discloses a kind of air pressure simulation mode ultrasonic auxiliary core-shell type abrasive magnetic rheological composite polishing processing manufacturing method, comprising the following steps:1) selecting workpiece clamp, install on ultrasonic vibration table;2) workpiece is clamped on workpiece clamp, and flexible polishing sleeve is wrapped workpiece outer surface;3) configuration has the novel composite polishing abrasive of core-shell type nano magnetic particle-grit polishing fluid, be placed in polishing fluid supply device;4) start airflow auxiliary module, under the assistance of high-pressure gas, so that flexible polishing sleeve and workpiece shape highly consistent, form with the " simulation flexible abrasive " similar to workpiece surface shape;5) start magnetic field control system;6) start ultrasonic transducer, ultrasonic vibration table drives workpiece high-frequency vibration, and " simulation flexible abrasive " generates relative motion micro-tribology of vibration.With the device of simultaneous provision, the application improves processing efficiency, solves abrasive holding force regulation and control and efficiently polishes different materials and shape workpiece and the like problem.

Description

Technical Field

[0001] This invention relates to the field of ultra-precision rheological polishing technology, specifically to a method and apparatus for manufacturing a magnetic rheological composite polishing process using pneumatically simulated ultrasonic-assisted core-shell abrasives. Background Technology

[0002] Ultra-precision machining technology is a crucial component of modern advanced manufacturing science and technology, widely applied in numerous fields, such as the processing and manufacturing of parts from hard and brittle materials like semiconductors, optical components, and functional ceramics, as well as ductile metals. It also involves ensuring high precision, low damage, and aesthetics for various complex curved surfaces. Ultra-precision machining technology can reduce surface roughness and surface or subsurface damage of workpieces. Complex curved surfaces are important working surfaces for many industrial products and parts, typically achieving high precision with specific mathematical characteristics while pursuing functional and aesthetically pleasing appearances. High-precision aspherical optical components for aerospace applications can improve the remote image recognition capabilities, accuracy, and stability of instruments; complex shapes in molded flexible abrasive cavities and automotive parts can achieve both functional requirements and aesthetic appeal. With the increasing demand and performance requirements for complex parts, there is an urgent need to improve the level of ultra-precision machining. Therefore, achieving efficient and high-quality ultra-precision machining of complex parts has become an important research direction for new methods and technologies in engineering manufacturing.

[0003] In composite abrasive polishing technology, the composite abrasives used are novel particles designed based on nanoparticle technology, possessing specific structures, appearances, and physicochemical properties. These particles are mostly composed of single hard particles combined with other particles, elements, or polymer chains through physical or chemical pathways. Composite abrasives can be classified into core-shell composite abrasives and doped composite abrasives according to their structure. Compared with traditional polishing methods using single abrasives, polishing with composite abrasives offers advantages such as achieving high surface accuracy, high polishing efficiency, extended polishing equipment lifespan, and reduced surface defects.

[0004] Magnetorheological polishing (MRP) is a surface polishing method that utilizes the rheological properties of magnetorheological fluids. Magnetorheological fluids are special materials whose flow characteristics change when exposed to a magnetic field, particularly becoming more viscous or fluid under the influence of an external magnetic field. In MRP, the magnetorheological fluid is applied to the surface to be polished, and its flow characteristics are managed by adjusting the external magnetic field to achieve the desired polishing effect. This technology enables high-precision polishing of complex shapes and tiny parts, thus showing broad application prospects in aerospace, automotive manufacturing, and other fields. MRP offers several advantages, including high precision in surface shaping, minimal surface roughness, no new damage during processing, ease of computer control, stability of the removal function, and controllable performance of the magnetorheological micro-grinding head. However, compared to composite abrasive processing, it still suffers from lower material removal efficiency and higher costs for magnetorheological fluids.

[0005] A published invention patent (CN110370093A) discloses a magnetic composite abrasive flow polishing method with an adjustable angle mechanism. In this method, abrasive flow processing is performed in a low-pressure fluid; the adjustable angle mechanism is placed within a processing device assisted by a magnetic field; the magnetic field is a uniformly strong, adjustable magnetic field perpendicular to the workpiece surface, generated by an electromagnet positioned directly below the processing device. Under the influence of this magnetic field, the magnetic composite abrasive particles in the flow field move towards the workpiece surface, effectively improving surface roughness uniformity. However, this patent still has room for improvement in terms of expanding the range of processed materials and enhancing performance.

[0006] A published invention patent (CN115820210A) discloses a composite abrasive for polishing, a polishing fluid, and a method for preparing the same. One magnetic composite abrasive is characterized by comprising multiple layers: a core of magnetic nanoparticles, an outer layer of polymer coating the magnetic nanoparticles, an outer layer of porous hybrid film coating the polymer, a first abrasive embedded in the porous hybrid film, and a second abrasive coated on the outer layer of the porous hybrid film. This patent effectively improves material removal rate and provides a better polishing effect, while minimizing surface scratches on the workpiece. However, the composite abrasive described in this patent faces challenges such as difficulty in controlling and managing the external abrasive particles, thus leaving room for improvement in workpiece shape accuracy and efficient polishing.

[0007] A published invention patent (CN115946032A) discloses a small-head magnetorheological polishing device and method. The device includes a machine tool body assembly, a three-dimensional motion assembly, a spindle drive assembly, a magnetorheological fluid circulation assembly, a polishing head assembly, a magnetic field generating device assembly, a differential motion assembly, and a workpiece clamping motion assembly. This invention's small-head magnetorheological polishing device enables the polishing head assembly to move in three dimensions via the three-dimensional motion assembly; the workpiece rotation is achieved by the workpiece drive shaft driven by the drive motor of the workpiece clamping motion assembly; the magnetorheological fluid in the polishing area is renewed through the differential motion between the polishing head assembly and the magnetic field generating device assembly; and the magnetorheological fluid is transported and recycled through the magnetorheological fluid circulation assembly. Compared to traditional magnetorheological polishing devices, the small-head magnetorheological polishing device provided by this invention improves workpiece polishing efficiency and quality, and achieves the functions of abrasive renewal and circulation in the polishing area. However, this patent does not involve mechanisms such as ultrasound or composite abrasives, and further improvements and enhancements are possible in terms of efficient polishing and material expansion. Summary of the Invention

[0008] In order to overcome the shortcomings of existing technologies and to further improve processing efficiency, solve problems such as abrasive holding force control and efficient polishing of workpieces of different materials and shapes, this invention provides a pneumatic simulation mode ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing processing method and device.

[0009] The technical solution adopted by this invention to solve its technical problem is:

[0010] A method for manufacturing a pneumatically simulated ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing process includes the following steps:

[0011] 1) Select a workpiece fixture and install it on the ultrasonic vibration table;

[0012] 2) Clamp the workpiece on the workpiece fixture and wrap the outer surface of the workpiece with a flexible polishing sleeve;

[0013] 3) Prepare a polishing slurry containing a composite abrasive of core-shell type nano-magnetic particles and abrasive grains, and then place it in a polishing slurry replenishment device;

[0014] 4) Activate the airflow assist module to quickly fill the airflow delivery device pipeline with high-pressure airflow; then activate the polishing fluid circulation and replenishment module to deliver the polishing fluid to the polishing worktable until the flexible polishing sleeve is completely submerged.

[0015] 5) Activate the magnetic field control system to generate a magnetic field under the action of the magnetic field generator. The novel composite polishing abrasive, consisting of core-shell type nano-magnetic particles and abrasive grains in the polishing fluid, enters the interior of the flexible polishing sleeve and forms a flexible polishing head on the inner surface of the polishing sleeve. With the assistance of high-pressure gas, the flexible polishing sleeve closely matches the shape of the workpiece, forming a "mold-imitating flexible abrasive" that closely resembles the surface shape of the workpiece.

[0016] 6) Start the ultrasonic transducer. The ultrasonic vibration table drives the workpiece to vibrate at a high frequency, generating micro-motion friction with the "mold-imitating flexible abrasive", thereby realizing pneumatic imitation mode ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing.

[0017] Furthermore, in step 3), the abrasive particles are one or a mixture of two or more of boron carbide, silicon carbide, silicon nitride, silicon oxide, and aluminum oxide, or core-shell composite abrasive particles, such as SiO2 / CeO2 nanocomposite abrasive particles.

[0018] In step 3), the nanomagnetic particles include ferrite (Fe3O4), iron, cobalt, nickel, and magnetic alloys.

[0019] The average diameter of the abrasive grains is 200–1000 nm.

[0020] The average diameter of the nanomagnetic particles is 50–100 nm.

[0021] In step 2), the polishing sleeve is a porous wear-resistant polishing sleeve with pre-reserved pores.

[0022] In step 4), the high-pressure airflow in the airflow-assisted module provides dynamic pressure to the polishing fluid, which not only helps the "mold-imitating flexible abrasive" to continuously adhere to the workpiece during the polishing process, but also provides power for the circulation of the polishing fluid, accelerating the removal of material debris adhering to the surface of the "mold-imitating flexible abrasive" and the continuous renewal of abrasive particles in the polishing fluid.

[0023] In step 5), the flexible polishing head is attached to the surface of the "mold-imitating flexible abrasive". This is achieved by free nano-magnetic particles in the polishing fluid forming a flexible polishing sleeve along the magnetic field distribution lines. A novel composite polishing abrasive, consisting of core-shell nano-magnetic particles and abrasive grains, adheres to the gaps in the flexible polishing sleeve, forming the so-called "flexible polishing head". During polishing, the novel composite polishing abrasive, consisting of core-shell nano-magnetic particles and abrasive grains, which constitute the "flexible polishing head", contacts the workpiece surface. The nano-magnetic abrasive grains are compressed and move towards the center, leaving the abrasive grains exposed and in contact with the workpiece. Accompanied by the ultrasonic vibration table driving the workpiece to vibrate at a high frequency, micro-motion friction occurs between the workpiece and the "mold-imitating flexible abrasive", achieving pneumatic imitation mode ultrasonic-assisted magnetic rheological polishing of the core-shell abrasive grains.

[0024] In step 2), the workpiece is a regular planar workpiece, a regular circular curved surface, or an irregular complex curved surface, and the workpiece material is silicon material, optical crystal, and various difficult-to-process materials, etc.

[0025] A pneumatically simulated ultrasonic-assisted core-shell abrasive magnetorheological composite polishing device includes an airflow assist module, a magnetic field generating module, a flexible polishing sleeve, a polishing fluid circulation and replenishment module, and an ultrasonic vibration table. The airflow assist module includes an airflow emitting device, an airflow conveying device, an airflow orifice, and a sealing coil. The airflow orifice is located on the inner wall of the airflow conveying device, and the sealing coil is located on the outer wall of the airflow conveying device. The airflow assist module is positioned above the polishing table. The magnetic field generating module includes a magnetic field control system, a magnetic field generating device, and a polishing table. The magnetic field generating device is attached to the inner wall of the polishing table and arranged in a circumferential array. The flexible polishing sleeve wraps around the workpiece and is fixed at its tail end to a protective sleeve, which in turn covers the workpiece clamp. The polishing fluid circulation and replenishment module delivers polishing fluid to the polishing table via a polishing fluid delivery pipe, and the polishing fluid flows back to the polishing fluid circulation and replenishment module from the polishing fluid pipe outlet valve. The ultrasonic vibration table is equipped with a workpiece clamp.

[0026] Furthermore, the ultrasonic vibration table includes an ultrasonic transducer, which includes a cylindrical pressure head, an amplitude transformer, a piezoelectric element, an electrode plate, a screw, and a nut. The cylindrical pressure head is connected to one end of the amplitude transformer, and the other end of the amplitude transformer is connected to the piezoelectric element. The piezoelectric element is provided with an electrode plate, and a screw is provided on the piezoelectric element to press it in place. A nut is provided on the screw. A workpiece clamp is provided on the cylindrical pressure head, and complex curved surface parts can be installed on the workpiece clamp. The cylindrical pressure head can drive the workpiece to vibrate at high frequency.

[0027] Furthermore, the polishing slurry circulation and replenishment module includes a polishing slurry replenishment device, a polishing slurry circulation system start-up device, a pH adjustment device, a temperature adjustment device, a polishing slurry delivery pipeline, a polishing slurry pipeline inlet valve, a polishing slurry pipeline outlet valve, and a collection device. During the polishing process, the polishing slurry circulation system start-up device is activated, and the polishing slurry flows out from the polishing slurry replenishment device, reaches the polishing worktable through the polishing slurry delivery pipeline, and flows out from the polishing slurry pipeline outlet valve into the collection device.

[0028] The protective sleeve is made of wear-resistant material, which not only provides a fixing point for the flexible polishing sleeve, but also prevents the workpiece fixture and ultrasonic vibration table from being worn during the polishing process.

[0029] The ultrasonic transducer has a vibration frequency of at least 26 kHz and a power of at least 180 W. Rubber damping washers are installed between the ultrasonic vibration table and the polishing worktable.

[0030] The prepared polishing slurry is added to the polishing slurry replenishment device, so that the polishing slurry is supplied to the surface of the workpiece through the polishing slurry delivery pipeline. The polishing slurry circulation module adjusts the pH value control device and the temperature control device according to different workpiece materials or processing requirements, so that the viscosity of the polishing slurry can quickly reach the critical point under the action of the magnetic field. The viscosity can achieve a steady-state intermittent transition from the critical point to the high viscosity point directly. Under the action of the magnetic field generating device, the high viscosity point can be maintained in a continuous and stable state, becoming more viscous, ensuring the uniformity of workpiece material removal and controllable surface shape accuracy.

[0031] During the polishing process, the polishing liquid slowly flows out from the inlet valve of the polishing liquid pipeline. Under the action of high-pressure airflow, it passes through the workpiece and slowly flows out from the outlet valve of the polishing liquid.

[0032] This invention employs a novel composite polishing abrasive consisting of core-shell type nano-magnetic particles and abrasive grains. The novel composite polishing abrasive consists of processing abrasive grains and magnetic nanoparticles. By controlling the particle structure through polymerization and modifying the chemical environment, the magnetic nanoparticles are aggregated on the surface of the processing abrasive grains, thus forming the novel composite polishing abrasive consisting of core-shell type nano-magnetic particles and abrasive grains.

[0033] The beneficial effects of this invention are mainly reflected in:

[0034] 1) Wide range of applications. This invention provides a novel composite polishing abrasive consisting of core-shell type nanomagnetic particles and abrasive grains. The abrasive grains are composed of processing abrasive grains and magnetic nanoparticles. The particle structure is controlled through polymerization and modified by chemical environment to form the novel composite polishing abrasive. During polishing, the core-shell composite magnetic abrasive grains contact the workpiece surface, and the nanomagnetic abrasive grains are compressed and move towards the center. At this point, the processing abrasive grains are exposed and contact the workpiece, thus achieving polishing. The appropriate processing abrasive grain can be selected according to the different types of materials being processed. For example, alumina abrasive grains are suitable for processing steel and ferrous metals, while silicon carbide is suitable for processing carbides, ceramics, cast iron, and tough non-ferrous metals.

[0035] 2) High machining precision, strong controllability, and efficient material removal. Because each abrasive grain is coated with magnetic particles, the machining direction can be precisely controlled via computer and an external magnetic field. This allows the polishing slurry of the novel composite abrasive—a core-shell type nano-magnetic particle-abrasive—to closely match the workpiece shape and effectively remove material, thus achieving precise machining. Compared to traditional abrasive machining, controllable composite abrasives significantly improve abrasive grain utilization, resulting in more efficient material removal.

[0036] 3) The composite magnetic abrasive particles have good dispersibility. The composite magnetic abrasive particles, which are constructed by electrostatic self-assembly, have the outermost nano-magnetic particles carrying the same charge. The individual composite magnetic abrasive particles repel each other, resulting in good dispersibility. This also eliminates the need for dispersants and reduces the difficulty of preparing polishing fluid.

[0037] 4) Highly efficient processing of complex curved surface parts. Under the action of the magnetic field control system, the polishing slurry of the novel composite polishing abrasive, which is composed of core-shell nano-magnetic particles and abrasive grains, closely matches the shape of the workpiece. The magnetic field generating device emits a strong magnetic field, causing the polishing slurry to change from a non-Newtonian fluid to a semi-solid with higher viscosity, forming a "mold-imitating flexible abrasive" that is similar in shape to the workpiece surface. Then, through friction and vibration, high-precision polishing of complex curved surfaces is achieved.

[0038] 5) High-pressure airflow is used to provide dynamic pressure for the polishing fluid, which not only helps the "mold-imitating flexible abrasive" to continuously adhere to the workpiece during the polishing process, but also provides power for the circulation of the polishing fluid, accelerating the removal of material debris adhering to the surface of the "mold-imitating flexible abrasive" and the continuous renewal of abrasive particles in the polishing fluid.

[0039] 6) The requirements for processing equipment are relatively low in this invention. Attached Figure Description

[0040] Figure 1 A schematic diagram illustrating the manufacturing principle of a novel composite polishing abrasive consisting of core-shell type nanomagnetic particles and abrasive grains.

[0041] Figure 2 This is a schematic diagram of a pneumatic simulation ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing and manufacturing device.

[0042] Figure 3 This is a schematic diagram of the airflow assist module device.

[0043] Figure 4 This is a cross-sectional view of the airflow auxiliary module.

[0044] Figure 5 This is a schematic diagram of an ultrasonic transducer.

[0045] The components include: 1. Abrasive particles; 2. Nanomagnetic particles; 3. Airflow generator; 4. Airflow conveying device; 5. Airflow orifice; 6. Magnetic field control system; 7. Magnetic field generator; 8. Polishing worktable; 9. Sealing coil; 10. Workpiece; 11. Workpiece fixture; 12. Ultrasonic vibration table; 13. Rubber vibration damping washer; 14. Polishing fluid replenishment device; 15. Polishing fluid circulation start-up device; 16. pH adjustment device; 17. Temperature adjustment device; 18. Polishing fluid delivery system. 19. Polishing fluid pipeline inlet valve; 20. Polishing fluid pipeline outlet valve; 21. Polishing fluid; 22. Collection device; 23. Flexible polishing sleeve; 24. Protective sleeve; 25. Imitative flexible abrasive; 121. Cylindrical pressure head; 122. Amplitude rod; 123. Piezoelectric element; 124. Electrode plate; 125. Screw; 126. Nut; 3-1. Magnetic field lines; 3-2. Extrusion; 3-3. High-frequency vibration; 3-4. Shearing; 3-5. High-pressure airflow. Detailed Implementation

[0046] The present invention will now be further described with reference to the accompanying drawings.

[0047] Reference Figures 1-5 A method for manufacturing a pneumatically simulated ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing process includes the following steps:

[0048] 1) Select a workpiece fixture and install it on the ultrasonic vibration table;

[0049] 2) The workpiece is clamped on the workpiece fixture and wrapped with a flexible polishing sleeve; the polishing sleeve is a porous wear-resistant polishing sleeve with pre-reserved holes; the workpiece is a regular planar workpiece, a regular circular curved surface or an irregular complex curved surface, and the workpiece material is silicon material, optical crystal and various difficult-to-machine materials, etc.

[0050] 3) Prepare a polishing slurry containing a composite abrasive of core-shell type nano-magnetic particles and abrasive grains, and then place it in a polishing slurry replenishment device;

[0051] The novel composite polishing abrasive of core-shell type nanomagnetic particles-abrasive is composed of abrasive 1 and magnetic nanoparticles 2. By controlling the particle structure through polymerization and modifying the chemical environment, the magnetic nanoparticles 2 are aggregated on the surface of abrasive 1 to form a novel composite polishing abrasive of core-shell type nanomagnetic particles-abrasive.

[0052] The abrasive grain 1 is one or a mixture of boron carbide, silicon carbide, silicon nitride, silicon oxide, and alumina, or a traditional core-shell composite abrasive grain, such as SiO2 / CeO2 nanocomposite abrasive grains. More specifically, different processing parts are required for different processing materials. Alumina abrasive grains are suitable for processing steel and ferrous metals, while silicon carbide is suitable for processing carbides, ceramics, cast iron, and tough non-ferrous metals.

[0053] The nanomagnetic particles 2 include ferrite (Fe3O4), iron, cobalt, nickel, and magnetic alloys. The particle size and concentration of the nanomagnetic particles 2 in the polishing fluid 3 should be selected according to the processing quality and efficiency of the polished parts.

[0054] The average diameter of abrasive particles 1 is 200–1000 nm. The average diameter of nanomagnetic particles 2 is 50–100 nm.

[0055] Polishing fluid 21 comprising the novel composite abrasive of core-shell magnetic nanoparticles-abrasive grains. Polishing fluid 21 was prepared in ultrapure water by adding the novel composite abrasive of core-shell magnetic nanoparticles-abrasive grains, a pH adjuster, a thickener, and an oxidant. The mass fraction of the novel composite abrasive of core-shell magnetic nanoparticles-abrasive grains was between 20% and 50%, the mass fraction of the pH adjuster was between 0.05% and 1.0%, the mass fraction of the thickener was between 0.05% and 1.0%, and the mass fraction of the oxidant was between 0.05% and 0.1%.

[0056] Alternatively, the pH adjuster may be an aqueous ammonia solution, sodium hydroxide, or potassium hydroxide.

[0057] 4) Activate the airflow assist module to quickly fill the airflow delivery device pipeline with high-pressure airflow; then activate the polishing fluid circulation and replenishment module to deliver the polishing fluid to the polishing worktable until the flexible polishing sleeve is completely submerged.

[0058] In the airflow assist module, the high-pressure airflow provides dynamic pressure to the polishing fluid, which not only helps the "mold-imitating flexible abrasive" to continuously adhere to the workpiece during the polishing process, but also provides power for the circulation of the polishing fluid, accelerating the removal of material debris adhering to the surface of the "mold-imitating flexible abrasive" and the continuous renewal of abrasive particles in the polishing fluid.

[0059] 5) Activate the magnetic field control system to generate a magnetic field under the action of the magnetic field generator. The new composite polishing abrasive material of core-shell type nano-magnetic particles-abrasive particles in the polishing fluid enters the interior of the flexible polishing sleeve and forms a flexible polishing head on the inner surface of the polishing sleeve. With the assistance of high pressure gas, the flexible polishing sleeve is highly consistent with the shape of the workpiece, forming a "mold-imitating flexible abrasive 25" that is similar to the shape of the workpiece surface.

[0060] The "mold-imitating flexible abrasive" has a flexible polishing head attached to its surface. Free nano-magnetic particles in the polishing fluid form a flexible polishing sleeve along the magnetic field distribution lines. A novel composite polishing abrasive, consisting of core-shell nano-magnetic particles and abrasive grains, adheres to the gaps in the flexible polishing sleeve, forming the so-called "flexible polishing head." During polishing, the novel composite polishing abrasive, consisting of core-shell nano-magnetic particles and abrasive grains, that constitute the "flexible polishing head" contacts the workpiece surface. The nano-magnetic abrasive grains are compressed and move towards the center, leaving the processed abrasive grains exposed and in contact with the workpiece. Accompanied by a high-frequency vibration of the workpiece driven by an ultrasonic vibration table, micro-motion friction occurs between the workpiece and the "mold-imitating flexible abrasive," achieving pneumatic imitation mode ultrasonic-assisted magnetic rheological polishing of the core-shell abrasive grains.

[0061] 6) Start the ultrasonic transducer. The ultrasonic vibration table drives the workpiece to vibrate at a high frequency, generating micro-motion friction with the "mold-imitating flexible abrasive", thereby realizing pneumatic imitation mode ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing.

[0062] A pneumatically simulated ultrasonic-assisted core-shell abrasive magnetorheological composite polishing device includes an airflow assist module, a magnetic field generating module, a flexible polishing sleeve 23, a polishing fluid circulation and replenishment module, and an ultrasonic vibration table 12. The airflow assist module includes an airflow emitting device 3, an airflow conveying device 4, an airflow hole 5, and a sealing coil 9. The magnetic field generating module includes a magnetic field control system 6, a magnetic field generating device 7, and a polishing worktable 8. The polishing fluid circulation and replenishment module includes a polishing fluid replenishment device 14, a polishing fluid circulation system starting device 15, a pH adjustment device 16, a temperature adjustment device 17, a polishing fluid conveying pipeline 18, a polishing fluid pipeline inlet valve 19, a polishing fluid pipeline outlet valve 20, and a collection device 22. The ultrasonic vibration table 12 includes an ultrasonic transducer, which comprises a cylindrical pressure head 121, an amplitude transformer 122, a piezoelectric element 123, an electrode sheet 124, a screw 125, and a nut 126.

[0063] The airflow auxiliary module includes an airflow launching device 3, an airflow conveying device 4, an airflow hole 5, and a sealing coil 9. The lower opening of the airflow launching device 3 is sealed to the upper opening of the airflow conveying device 4. The airflow hole 5 is located on the inner wall of the airflow conveying device 4, and the sealing coil 9 is located on the outer wall of the airflow conveying device 4. The airflow auxiliary module is located above the polishing worktable 8.

[0064] The magnetic field generating module includes a magnetic field control system 6, a magnetic field generating device 7, and a polishing worktable 8. The magnetic field control system 6 is located on the right side of the device and is an independent control unit outside the device. The magnetic field generating device 7 is attached to the inner wall of the polishing worktable 8 and arranged in a circular array. An ultrasonic vibration table 12 is set at the center of the polishing worktable 8, and a rubber shock-absorbing washer 13 is set between the ultrasonic vibration table 12 and the polishing worktable 8.

[0065] The flexible polishing sleeve 23 wraps around the workpiece 10 and is fixed at the tail end to the protective sleeve 24, which covers the workpiece clamp 11.

[0066] The protective sleeve 24 is made of wear-resistant material, which not only provides a fixing point for the flexible polishing sleeve 23, but also prevents the workpiece clamp 11 and the ultrasonic vibration table 12 from being worn during the polishing process.

[0067] The polishing slurry circulation and replenishment module includes a polishing slurry replenishment device 14, a polishing slurry circulation system start-up device 15, a pH adjustment device 16, a temperature adjustment device 17, a polishing slurry delivery pipeline 18, a polishing slurry pipeline inlet valve 19, a polishing slurry pipeline outlet valve 20, and a collection device 22. The temperature adjustment device 17 is embedded in the pH adjustment device 16 and attached to the polishing slurry delivery pipeline 18. During polishing, the polishing slurry circulation system start-up device 15 is activated, and polishing slurry 21 flows out from the polishing slurry replenishment device 14, reaches the polishing worktable 8 through the polishing slurry delivery pipeline 18, and flows out from the polishing slurry pipeline outlet valve 20 into the collection device 22.

[0068] The ultrasonic vibration table 12 includes an ultrasonic transducer, which comprises a cylindrical pressure head 121, an amplitude transformer 122, a piezoelectric element 123, an electrode plate 124, a screw 125, and a nut 126. The cylindrical pressure head 121 is connected to one end of the amplitude transformer 122, and the other end of the amplitude transformer 122 is connected to the piezoelectric element 123. The piezoelectric element 123 is equipped with an electrode plate 124, and a screw 125 is provided on the piezoelectric element 123 to press it down. A nut 126 is provided on the screw 125. A workpiece clamp 11 is provided on the cylindrical pressure head 121, on which a workpiece 10 can be mounted. The cylindrical pressure head 121 can drive the workpiece 10 to vibrate at a high frequency. The vibration frequency of the ultrasonic transducer is at least 26 kHz, and the power is at least 180 W.

[0069] The prepared polishing slurry 21 is added to the polishing slurry replenishment device 14, so that the polishing slurry 21 is supplied to the surface of the workpiece 10 through the polishing slurry delivery pipe 18. The pH control device 16 and the temperature control device 17 are adjusted by the polishing slurry circulation module according to different workpiece materials or processing requirements, so that the viscosity of the polishing slurry 21 can quickly reach the critical point under the action of the magnetic field, realize the steady-state intermittent transition of viscosity from the critical point to the high viscosity point, and maintain the continuous stable state of high viscosity point under the action of the magnetic field generating device 7, becoming more viscous, ensuring the uniformity of workpiece material removal and controllable surface shape accuracy.

[0070] During the polishing process, the polishing liquid 21 slowly flows out from the inlet valve 19 of the polishing liquid pipeline. Under the action of high-pressure airflow, it passes through the workpiece and slowly flows out from the outlet valve 20 of the polishing liquid.

[0071] The polishing method for the workpiece 10 in this embodiment includes the following steps:

[0072] 1) Select workpiece fixture 11 and install it on ultrasonic vibration table 12;

[0073] 2) Clamp the workpiece 10 on the workpiece fixture 11 and wrap the outer surface of the workpiece 10 with a flexible polishing sleeve 23;

[0074] 3) Prepare a polishing slurry 21 with a novel composite abrasive containing core-shell type nano-magnetic particles-abrasive grains, and then place it in the polishing slurry replenishment device 14;

[0075] 4) Activate the airflow assist module to quickly fill the airflow delivery device pipe 4 with high-pressure airflow; then activate the polishing fluid circulation and replenishment module to deliver polishing fluid 21 to the polishing worktable 8 until the flexible polishing sleeve 23 is completely submerged.

[0076] 5) Start the magnetic field control system 6. Under the action of the magnetic field generating device 7, a magnetic field is generated. The new composite polishing abrasive of core-shell type nano magnetic particles-abrasive particles in the polishing liquid 21 enters the interior of the flexible polishing sleeve 23 and forms a flexible polishing head on the inner surface of the polishing sleeve 23. With the assistance of high pressure gas, the flexible polishing sleeve 23 is highly consistent with the shape of the workpiece 10, forming a "mold-imitating flexible abrasive" that is similar to the shape of the workpiece surface.

[0077] 6) Start the ultrasonic transducer. The ultrasonic vibration table 12 drives the workpiece 10 to vibrate at a high frequency, generating micro-motion friction with the "mold-imitating flexible abrasive", thereby realizing the composite processing and manufacturing of pneumatic imitation ultrasonic-assisted core-shell abrasive magnetic rheological polishing.

[0078] The embodiments described in this specification are merely examples of implementations of the inventive concept and are for illustrative purposes only. The scope of protection of this invention should not be considered limited to the specific forms described in these embodiments; rather, it extends to equivalent technical means conceived by those skilled in the art based on the inventive concept.

Claims

1. A method for manufacturing a pneumatically simulated ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing process, characterized in that, The method includes the following steps: 1) Select a workpiece fixture and install it on the ultrasonic vibration table; 2) Clamp the workpiece on the workpiece fixture and wrap the outer surface of the workpiece with a flexible polishing sleeve; 3) Prepare a polishing slurry containing a novel composite abrasive with core-shell type nano-magnetic particles-abrasive grains, and then place it in a polishing slurry replenishment device; 4) Activate the airflow assist module to quickly fill the airflow delivery device pipeline with high-pressure airflow; then activate the polishing fluid circulation and replenishment module to deliver the polishing fluid to the polishing worktable until the flexible polishing sleeve is completely submerged. 5) Start the magnetic field control system. Under the action of the magnetic field generator, a magnetic field is generated. The new composite polishing abrasive of core-shell type nano magnetic particles-abrasive particles in the polishing liquid enters the interior of the flexible polishing sleeve and forms a flexible polishing head on the inner surface of the flexible polishing sleeve. With the assistance of high pressure gas, the flexible polishing sleeve is highly matched with the shape of the workpiece, forming a "modeling flexible abrasive" that is similar to the shape of the workpiece surface. The "mold-imitating flexible abrasive" has a flexible polishing head attached to its surface. This head is formed by free nano-magnetic particles in the polishing fluid forming a flexible polishing sleeve along the magnetic field distribution lines. A novel composite polishing abrasive of core-shell nano-magnetic particles-abrasive grains is attached to the gaps in the flexible polishing sleeve, forming the so-called "flexible polishing head". During the polishing process, the novel composite polishing abrasive of core-shell nano-magnetic particles-abrasive grains that constitute the "flexible polishing head" comes into contact with the workpiece surface. The nano-magnetic abrasive grains are squeezed and move towards the center. At this time, the processed abrasive grains are exposed and come into contact with the workpiece. Accompanied by the ultrasonic vibration table driving the workpiece to vibrate at a high frequency, a micro-motion friction is generated between the workpiece and the "mold-imitating flexible abrasive", realizing pneumatic imitation mode ultrasonic-assisted magnetic rheological polishing of core-shell abrasive grains. 6) Start the ultrasonic transducer. The ultrasonic vibration table drives the workpiece to vibrate at a high frequency, generating micro-motion friction with the "mold-imitating flexible abrasive", thereby realizing pneumatic imitation mode ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing.

2. The method for manufacturing pneumatically simulated ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing as described in claim 1, characterized in that, In step 3), the novel composite polishing abrasive with core-shell type nanomagnetic particles-abrasive particles includes abrasive particles and nanomagnetic particles. The abrasive particles are one or a mixture of two or more of boron carbide, silicon carbide, silicon nitride, silicon oxide and aluminum oxide, or core-shell type composite abrasive particles. The nanomagnetic particles include ferrite (Fe3O4), iron, cobalt, nickel, and magnetic alloys.

3. The method for manufacturing pneumatically simulated ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing as described in claim 2, characterized in that, In step 3), the average diameter of the abrasive grains is 200~1000nm, and the average diameter of the nanomagnetic particles is 50~100nm.

4. The pneumatic simulation ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing manufacturing method as described in any one of claims 1 to 3, characterized in that, In step 2), the flexible polishing sleeve is a porous wear-resistant polishing sleeve with pre-reserved pores.

5. The method for manufacturing a pneumatically simulated ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing process as described in any one of claims 1 to 3, characterized in that, In step 4), the high-pressure airflow in the airflow-assisted module provides dynamic pressure to the polishing fluid, which not only helps the "mold-imitating flexible abrasive" to continuously adhere to the workpiece during the polishing process, but also provides power for the circulation of the polishing fluid, accelerating the removal of material debris adhering to the surface of the "mold-imitating flexible abrasive" and the continuous renewal of abrasive particles in the polishing fluid.

6. The method for manufacturing a pneumatically simulated ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing process as described in any one of claims 1 to 3, characterized in that, In step 2), the workpiece is a regular planar workpiece, a regular circular curved surface, or an irregular complex curved surface, and the workpiece material is silicon material or optical crystal.

7. An apparatus for implementing the pneumatic simulation mode ultrasonic-assisted core-shell abrasive magnetic rheological composite polishing manufacturing method as described in claim 1, characterized in that, The device includes an airflow assist module, a magnetic field generating module, a flexible polishing sleeve, a polishing fluid circulation and replenishment module, and an ultrasonic vibration table. The airflow assist module includes an airflow emitting device, an airflow conveying device, an airflow hole, and a sealing coil. The airflow hole is located on the inner wall of the airflow conveying device, and the sealing coil is located on the outer wall of the airflow conveying device. The airflow assist module is located above the polishing worktable. The magnetic field generating module includes a magnetic field control system, a magnetic field generating device, and a polishing worktable. The magnetic field generating device is attached to the inner wall of the polishing worktable and arranged in a circumferential array. The flexible polishing sleeve wraps around the workpiece and is fixed to a protective sleeve at its tail end. The protective sleeve covers the workpiece fixture. The polishing fluid circulation and replenishment module reaches the polishing worktable through a polishing fluid delivery pipe, and the polishing fluid flows back to the polishing fluid circulation and replenishment module from the polishing fluid pipe outlet valve. The ultrasonic vibration table is equipped with a workpiece fixture.

8. The apparatus as claimed in claim 7, characterized in that, The ultrasonic vibration table includes an ultrasonic transducer, which comprises a cylindrical indenter, an amplitude transformer, a piezoelectric element, electrode plates, a screw, and a nut. The cylindrical indenter is connected to one end of the amplitude transformer, and the other end of the amplitude transformer is connected to the piezoelectric element. Electrode plates are provided on the piezoelectric element, and a screw is provided on the piezoelectric element to press it in place. A nut is provided on the screw. A workpiece clamp is provided on the cylindrical indenter, on which complex curved surface parts can be mounted. The cylindrical indenter can drive the workpiece to vibrate at high frequency.

9. The apparatus as claimed in claim 7 or 8, characterized in that, The polishing slurry circulation and replenishment module includes a polishing slurry replenishment device, a polishing slurry circulation system start-up device, a pH adjustment device, a temperature adjustment device, a polishing slurry delivery pipeline, a polishing slurry pipeline inlet valve, a polishing slurry pipeline outlet valve, and a collection device. During the polishing process, the polishing slurry circulation system start-up device is activated, and the polishing slurry flows out from the polishing slurry replenishment device, reaches the polishing worktable through the polishing slurry delivery pipeline, and flows out from the polishing slurry pipeline outlet valve into the collection device.

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