A polishing liquid circulating system for polishing a large-aperture superhard optical element

Abstract

The application discloses a polishing liquid circulating system for polishing large-diameter superhard optical elements, which comprises a stirring barrel, a clamping assembly and a circulating assembly; the outer wall bottom end of the stirring barrel is provided with an inlet valve and an outlet valve; a plurality of stirring barrels are configured as rough polishing barrels, fine polishing barrels and final polishing barrels; the clamping assembly comprises a workbench, a clamp and a backflow tank; the clamp is connected to the top surface of the workbench; the backflow tank is fixed to the outer wall of the workbench and is arranged in an inclined manner; the circulating assembly comprises a circulating pump, an outlet pipe, a polishing pipe and a circulating pipe; the first end of the outlet pipe is detachably connected with the outlet valve, and the second end is communicated with the inlet of the circulating pump; the first end of the polishing pipe is communicated with the outlet of the circulating pump, and the second end is fixed with a nozzle for spraying polishing liquid to the surface of the optical element; the first end of the circulating pipe is communicated with the backflow tank, and the second end is detachably connected with the inlet valve. The application solves the problems of high processing cost, difficult surface shape precision control and poor process adaptability of large-diameter superhard material optical elements.

Description

Technical Field

[0001] This invention relates to the field of optical processing technology, and more specifically to a polishing fluid circulation system for polishing large-diameter ultrahard optical elements. Background Technology

[0002] In modern high-end optical systems, large-aperture aspherical superhard material optical components (such as silicon carbide, diamond, sapphire, and fused silica) have become indispensable core components in cutting-edge fields such as astronomical observation, space exploration, and laser nuclear fusion due to their outstanding characteristics such as high hardness, excellent thermal stability, low coefficient of thermal expansion, and good chemical stability. However, these materials, with hardness reaching 9.3 (close to diamond), have long faced challenges in sub-aperture processing, including high processing costs, difficulty in controlling surface accuracy, and poor process adaptability, severely restricting the progress and application efficiency of related optical equipment.

[0003] The polishing fluid circulation system, as a key piece of equipment to ensure the continuity and stability of processing, plays an important role in the storage, transportation, filtration, and recycling of polishing fluid. Polishing fluid typically contains nanoscale superhard abrasives (such as diamond micron powder) and special chemical active ingredients. Its concentration stability and particle dispersion uniformity directly affect the stability of the material removal function and the surface convergence efficiency.

[0004] Traditional polishing fluid circulation systems typically require a circulating solution reserve of over 40L to ensure processing continuity. Since polishing slurries for machining superhard materials often contain expensive nano-sized diamond powder and other superhard abrasives, as well as specialized chemical additives, the large volume of circulating fluid preparation, loss, and waste disposal directly increases overall processing costs, severely hindering the economic viability of mass production of large-diameter components. Existing systems struggle to effectively suppress abrasive particle sedimentation and agglomeration, as well as chemical component volatilization, leading to fluctuations in polishing slurry concentration and unstable removal functions. Existing systems also suffer from complex and bulky piping layouts, resulting in significant component loss and cross-contamination risks during slurry transport. Furthermore, machining large-diameter superhard materials involves multiple stages, including rough polishing, fine polishing, and final polishing, each with significantly different requirements for abrasive particle size and chemical composition. Existing systems often use fixed circulation tanks, requiring thorough cleaning and pipeline disassembly for slurry replacement—a cumbersome and time-consuming process that easily leads to cross-contamination between different slurries, severely impacting process continuity and processing quality consistency.

[0005] Existing polishing material recycling technology suffers from prominent problems such as high cost, poor stability, and insufficient process flexibility in the processing of superhard materials. It has become a key bottleneck restricting the processing efficiency, accuracy, and economy of large-diameter superhard material optical components. Therefore, it is urgent to develop a high-efficiency, stable, low-cost, and high-quality polishing material recycling system specifically designed for the sub-diameter processing characteristics of superhard materials. Summary of the Invention

[0006] In view of this, the present invention provides a polishing slurry circulation system for polishing large-diameter ultrahard optical components, which solves the problems of cleaning the circulation tank, cross-contamination of polishing slurry, and process disconnection caused by using a single circulation tank to alternately replace polishing slurry at different polishing stages in the prior art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A polishing slurry circulation system for polishing large-aperture ultrahard optical components includes: The mixing tanks are multiple; each of the multiple mixing tanks is provided with an inlet valve and an outlet valve at the bottom of its outer wall; the multiple mixing tanks are respectively configured as a coarse polishing tank, a fine polishing tank, and a final polishing tank; the coarse polishing tank, the fine polishing tank, and the final polishing tank are respectively filled with a coarse polishing solution, a fine polishing solution, and a final polishing solution. A clamping assembly includes a worktable, a clamp, and a return channel; the clamp is rotatably connected to the top surface of the worktable to clamp optical elements; the return channel is fixed to the outer wall of the worktable and is arranged at an angle to receive the polishing liquid flowing downstream after polishing. The circulation assembly includes a circulation pump, a liquid outlet pipe, a polishing pipe, and a circulation tube. The first end of the liquid outlet pipe is detachably connected to a liquid outlet valve on the rough polishing tank, fine polishing tank, or final polishing tank, depending on the processing stage, and the second end is connected to the inlet of the circulation pump. The first end of the polishing tube is connected to the outlet of the circulation pump, and the second end is fixed with a nozzle for spraying polishing liquid onto the surface of the optical element. The first end of the circulation tube is connected to the return tank, and the second end is detachably connected to a liquid inlet valve on the rough polishing tank, fine polishing tank, or final polishing tank corresponding to the liquid outlet pipe.

[0009] The beneficial effects of the technical solution of this invention are that by setting up multiple mixing tanks to hold coarse polishing solution, fine polishing solution and final polishing solution respectively, the liquid outlet pipe and circulation pipe can be connected to the liquid outlet valve and liquid inlet valve on the corresponding mixing tank at different polishing stages. The replacement process does not require disassembling the pipeline, and only simple docking is required to complete the switching between different mixing tanks. It adapts to the needs of multi-process step-by-step processing, not only simplifying the operation process, but also avoiding the problem of cross-contamination of polishing liquid, and providing convenience for switching processing technology.

[0010] Preferably, the mixing tank includes a tank body, a tank lid, and a stirrer; the top of the tank body is open; the tank lid is detachable and covers the open end of the tank body; the body of the stirrer is fixed to the top surface of the tank lid, and its stirring shaft passes through the tank lid and is inserted into the tank body. By setting the stirrer to agitate the polishing liquid in the tank, the abrasive particles are broken up in real time, avoiding the problem of uneven concentration of polishing liquid due to particle sedimentation.

[0011] Preferably, the coarse polishing solution is prepared from large-particle diamond / silicon carbide abrasive and a strongly alkaline / acidic chemical solution, and the agitator on the coarse polishing tank adopts a high-speed stirring mode; the fine polishing solution is prepared from fine cerium oxide / silica abrasive and a neutral / weakly alkaline chemical solution, and the agitator on the fine polishing tank adopts a medium-speed stirring mode; the final polishing solution is prepared from nano-sized colloidal silica and a surfactant, and the agitator on the final polishing tank adopts a low-speed stirring mode. Different stirring modes are set for the agitator according to the process characteristics of different polishing stages and the properties of the polishing solution used, achieving precise matching of parameters during the polishing process and ensuring processing efficiency and accuracy.

[0012] Preferably, the volumes of the coarse polishing tank, fine polishing tank, and final polishing tank decrease sequentially. By setting different volumes to meet the minimum circulating solution volume requirements of different polishing stages, the initial input of polishing fluid is significantly reduced, and the frequency of waste liquid treatment and replenishment is also reduced. This achieves a significant reduction in processing costs from the source of consumable consumption, and is particularly suitable for cost control requirements in the mass production of large-diameter components.

[0013] Preferably, the circulation assembly further includes a filter and a filter tube; the first end of the filter tube is connected to the outlet of the circulation pump, and the second end is connected to the liquid inlet at the top of the filter; the first end of the polishing tube is connected to the liquid outlet at the bottom of the filter. The filter is used to filter residual particles in the polishing solution, ensuring the purity of the polishing solution and guaranteeing the polishing quality of the optical component surface.

[0014] Preferably, the system also includes a protective cabinet, in which multiple mixing tanks, the circulation pump, and the filter are integrated into the inner bottom wall of the protective cabinet. Using a protective cabinet enables integrated installation of the system, reducing the floor space required and making it more convenient to use.

[0015] Preferably, the system also includes a concentration detector; each of the multiple stirring tanks is equipped with a concentration detector for detecting the solution concentration; the concentration detector is fixed to the top surface of the protective cabinet and electrically connected to the multiple concentration detectors. Monitoring the concentration of the polishing solution using the concentration detector ensures polishing quality.

[0016] Preferably, the inclination angle of the reflux trough is not less than 60°; a circulation valve is fixed at the lower end of the reflux trough in the inclination direction; and the first end of the circulation pipe is detachably connected to the circulation valve. The inclination of the reflux trough ensures that the polishing liquid can flow back to its corresponding mixing tank, preventing waste of polishing liquid and reducing processing costs.

[0017] Preferably, the spray section of the nozzle is equipped with a micro-array nozzle, the orifice diameter of which is 0.2~0.5mm and the spray pressure is 0.1~0.3 bar. This low-pressure spraying method ensures that the polishing slurry accurately covers the area of ​​the optical element to be processed.

[0018] Preferably, the circulating pump is a micro peristaltic pump or a diaphragm pump with a flow rate range of 1-50 mL / min.

[0019] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a polishing fluid circulation system for polishing large-aperture ultrahard optical elements, which has the following beneficial effects: 1. Streamlined Circulating Fluid Consumption, Significantly Reducing Processing Costs: Traditional polishing slurry circulation systems require a circulating solution reserve of over 40L to ensure continuous processing. However, polishing slurries for processing superhard materials often contain nano-sized abrasives and specialized chemical active ingredients, resulting in high raw material costs. The large volume of circulating fluid preparation and consumption directly increases the overall processing cost. This invention, by setting stirring tanks of different volumes, allows for the setting of minimum circulating fluid volumes according to the process requirements of different polishing stages. This not only significantly reduces the initial input of polishing slurry but also lowers the frequency of waste fluid treatment and replenishment, achieving a significant reduction in processing costs from the source of consumable consumption. It is particularly suitable for cost control needs in mass production scenarios of large-diameter components.

[0020] 2. Enhance the stability of the polishing slurry and accelerate the surface convergence process: Fluctuations in polishing slurry concentration and instability in the removal function are key factors leading to repeated surface errors and lengthy processing cycles. This invention employs a high-efficiency stirring device to break up agglomerates of abrasive particles in real time, avoiding uneven concentration caused by particle sedimentation; at the same time, it optimizes the pipeline layout, shortens the polishing slurry circulation path, and reduces component loss during transmission.

[0021] 3. Flexible Switching for Multiple Processes: The processing of large-diameter aspherical superhard materials involves multiple stages, including rough polishing, fine polishing, and final polishing. Different stages have significantly different requirements for the abrasive particle size and chemical composition of the polishing slurry. Some complex processes even require alternating between different polishing slurries. Traditional circulation systems typically have fixed circulation tanks, requiring thorough cleaning when changing the polishing slurry. This cumbersome operation is prone to cross-contamination, severely impacting process continuity. This invention uses dedicated mixing tanks for different processing stages. The switching process requires no disassembly of pipelines; a simple connection is all that's needed. This design perfectly adapts to the needs of multi-process, step-by-step processing, simplifying the operation process, avoiding cross-contamination of the polishing slurry, and facilitating process switching. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the circulatory system structure provided by the present invention; Figure 2 for Figure 1 A schematic diagram of the structure of the central protective cabinet after the outer wall has been removed; Figure 3 This is a schematic diagram of the mixing tank structure provided by the present invention; Figure 4 This is a schematic diagram of the clamping assembly structure provided by the present invention.

[0024] Among them, 1-protective cabinet; 11-cabinet door; 2-mixing tank; 21-coarse polishing tank; 22-fine polishing tank; 23-final polishing tank; 24-stirrer; 25-concentration detector; 26-discharge valve; 27-inlet valve; 3-circulation assembly; 31-circulation pump; 32-filter; 33-discharge pipe; 34-filter tube; 35-polishing tube; 36-nozzle; 37-circulation pipe; 4-clamping assembly; 41-workbench; 42-clamp; 43-reflux tank; 44-circulation valve; 5-concentration detector; 6-optical element. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] See appendix Figure 1 To be continued Figure 4 According to an embodiment of the present invention, a polishing slurry circulation system for polishing large-aperture superhard optical components aims to solve the problems of high processing cost, difficulty in controlling surface accuracy, and poor process adaptability in the current processing of optical components made of large-aperture superhard materials. The system includes a stirring tank 2, a clamping assembly 4, and a circulation assembly 3. Multiple stirring tanks 2 are included; each stirring tank 2 has an inlet valve 27 and an outlet valve 26 at the bottom of its outer wall; the multiple stirring tanks 2 are respectively configured as a rough polishing tank 21, a fine polishing tank 22, and a final polishing tank 23; the rough polishing tank 21, fine polishing tank 22, and final polishing tank 23 contain rough polishing solution, fine polishing solution, and final polishing solution, respectively; the clamping assembly 4 includes a worktable 41, a clamp 42, and a return trough 43; the clamp 42 is rotatably connected to the worktable. The top surface of the workbench 41 is used to clamp the optical element 6; the return trough 43 is fixed to the outer wall of the workbench 41 and is arranged at an angle to receive the polishing liquid flowing downstream after polishing; the circulation assembly 3 includes a circulation pump 31, an outlet pipe 33, a polishing pipe 35 and a circulation pipe 37; the first end of the outlet pipe 33 can be detachably connected to the outlet valve 26 on the rough polishing barrel 21, the fine polishing barrel 22 or the final polishing barrel 23 according to the processing stage, and the second end is connected to the inlet of the circulation pump 31; the first end of the polishing pipe 35 is connected to the outlet of the circulation pump 31, and the second end is fixed with a nozzle 36 for spraying polishing liquid onto the surface of the optical element 6; the first end of the circulation pipe 37 is connected to the return trough 43, and the second end is detachably connected to the inlet valve 27 on the rough polishing barrel 21, the fine polishing barrel 22 or the final polishing barrel 23 used in the corresponding processing stage.

[0027] In practical use, the coarse polishing solution is prepared with high-concentration (20-30wt%) large-particle diamond / silicon carbide abrasive (particle size 5-20μm) and a strongly alkaline / acidic chemical solution, corresponding to a high-speed stirring mode on the agitator 24 of the coarse polishing tank 21; the fine polishing solution is prepared with fine cerium oxide / silica abrasive (particle size 0.5-2μm) and a neutral / weakly alkaline chemical solution, corresponding to a medium-speed stirring mode on the agitator 24 of the fine polishing tank 22; the final polishing solution is prepared with nano-sized colloidal silica (particle size <100nm) and a surfactant, corresponding to a low-speed stirring mode on the agitator 24 of the final polishing tank 23. To cope with the high-speed stirring mode, the stirring blades on the agitator 24 of the coarse polishing tank 21 are powerful mechanical stirring blades.

[0028] During the processing of optical components, in the rough polishing stage, the first end of the outlet pipe is connected to the outlet valve on the rough polishing tank, and the second end of the circulation pipe is connected to the inlet valve on the rough polishing tank, forming a complete rough polishing solution circulation loop. After rough polishing, fine polishing is performed. The first end of the outlet pipe and the second end of the circulation pipe are disconnected, and the first end of the outlet pipe is connected to the outlet valve on the fine polishing tank, and the second end of the circulation pipe is connected to the inlet valve on the fine polishing tank, forming a complete fine polishing solution circulation loop. After fine polishing, final polishing is performed. The first end of the outlet pipe and the second end of the circulation pipe are disconnected, and the first end of the outlet pipe is connected to the outlet valve on the rough polishing tank, and the second end of the circulation pipe is connected to the inlet valve on the fine polishing tank, forming a complete final polishing solution circulation loop.

[0029] In this embodiment, the volumes of the coarse polishing tank 21, fine polishing tank 22, and final polishing tank 23 decrease sequentially. To ensure the quality of the final polishing, the inner wall of the final polishing tank 23 is lined with mirror-polished PFA. Specifically, the volume of the coarse polishing tank 21 is 50L, the volume of the fine polishing tank 22 is 30L, and the volume of the final polishing tank 23 is 1L. The coarse polishing tank 21, fine polishing tank 22, and final polishing tank 23 are all prefabricated. The outlet pipe 33 and circulation pipe 37 can be connected to the corresponding tank according to the processing stage. There is no need to disassemble the pipeline; simply connecting the pipe to the valve is sufficient to select different processing stages. This perfectly adapts to the needs of multi-process step-by-step processing, simplifies the operation process, avoids cross-contamination of polishing fluid, and provides convenience for switching processing processes. Furthermore, the minimum circulating solution volume is reduced to 1L, which is only 1 / 40 of the traditional system. This not only significantly reduces the initial input of polishing fluid but also reduces the frequency of waste liquid treatment and replenishment, achieving a significant reduction in processing costs from the source of consumable consumption.

[0030] In this embodiment, the mixing tank 2 includes a tank body, a tank lid, and a stirrer 24; the top of the tank body is open; the tank lid can be detachably closed to the open end of the tank body; the body of the stirrer 24 is fixed to the top surface of the tank lid, and its stirring shaft passes through the tank lid and is inserted into the tank body.

[0031] The agitator uses a pneumatic agitator with stepless adjustment of the stirring speed from 50 to 1500 rpm. This maintains uniform particle suspension (settling rate <0.1% / h) while avoiding abrasive breakage or chemical component degradation due to excessive shearing.

[0032] To further optimize the above technical solution and ensure the polishing quality of the optical components, the circulation assembly 3 also includes a filter 32 and a filter tube 34; the first end of the filter tube 34 is connected to the outlet of the circulation pump 31, and the second end is connected to the liquid inlet at the top of the filter 32; the first end of the polishing tube 35 is connected to the liquid outlet at the bottom of the filter 32.

[0033] The filter has a diameter of 150mm and a height of 250mm. The filter housing is made of hard aluminum alloy, with a filtration accuracy of 0.5-5μm. It has a rejection rate of >95% for impurities with a particle size ≥1μm in optical polishing slurries, ensuring that there are no residual particles in the polishing slurry that could affect the surface quality of components after filtration. The filter element is made of a material resistant to the chemical corrosion of the polishing slurry and can withstand the erosion and wear of abrasive particles in the polishing slurry. The filter element is also equipped with a differential pressure sensor. The signal from the differential pressure sensor indicates whether the filter element needs to be replaced. If the differential pressure signal from the sensor reaches the maximum threshold, it indicates that the filter element is clogged or its filtration performance has deteriorated, and the filter element needs to be replaced.

[0034] To further optimize the above technical solution, the circulating pump 31 is a high-precision, low-pulse micro peristaltic pump or diaphragm pump with a flow rate range of 1-50 mL / min and a power of less than 10W.

[0035] To further optimize the above technical solution, a protective cabinet 1 is also included, and multiple mixing tanks 2, a circulation pump 31 and a filter 32 are all integrated into the inner bottom wall of the protective cabinet 1.

[0036] like Figure 1 As shown, a cabinet door 11 is hinged to the protective cabinet 1. The circulation pump 31 and filter 32 are located on the inner bottom wall of the protective cabinet 1 on the side corresponding to the cabinet door 11. The stirring tank 2 is located on the inner bottom wall of the protective cabinet 1 on the side away from the cabinet door 11. The liquid outlet pipe 33, filter pipe 34, and polishing pipe 35 are all located inside the protective cabinet 1. The second end of the polishing pipe 35 penetrates the side wall of the protective cabinet 1 opposite to the cabinet door 11 and is fastened to the workbench 41 by a snap-fit. The second end of the circulation pipe 37 penetrates the side wall of the protective cabinet 1 opposite to the cabinet door 11 and can be connected to the coarse polishing tank 21, fine polishing tank 22, or final polishing tank 23.

[0037] In this embodiment, the pipeline is made of ultra-fine chemically inert material with an inner diameter of 1.5-3mm and PFA / PTFE material, which significantly reduces the dead volume of the system. The pipeline layout adopts large-radius smooth bends instead of right-angle elbows to minimize flow resistance and ensure efficient and stable delivery of the solution.

[0038] To further optimize the above technical solution, the spray section of the nozzle 36 is equipped with a micro array nozzle. The orifice diameter of the micro array nozzle is 0.2 ~ 0.5 mm, the spray pressure is 0.1 ~ 0.3 bar, and the micro array nozzle adopts a 30° lateral incident angle design to ensure that the polishing liquid accurately covers the processing area. After experimentation, the coverage efficiency of the polishing liquid is >95%.

[0039] Experiments have verified that during 20 hours of continuous operation, the polishing slurry concentration reduction of the system is less than 3%, and the material removal function stability is over 95%. This highly stable processing environment ensures precise matching between the surface convergence and the preset processing model, effectively reducing the number of process iterations and corrections, significantly shortening the overall processing cycle of large-diameter aspherical components, and providing technical support for the rapid delivery of high-precision components.

[0040] To further optimize the above technical solution, a concentration detector 5 is also included; each of the multiple stirring tanks 2 is equipped with a concentration detector 25 for detecting the solution concentration; the concentration detector 5 is fixed on the top surface of the protective cabinet 1 and electrically connected to the multiple concentration detectors 25. The concentration detector 25 is a high-precision, real-time online polishing concentration detector, which realizes continuous monitoring and data feedback of the polishing solution concentration, ensures that the polishing solution concentration is stable within the process requirement range, improves the controllability of the high-precision optical component polishing process, and the detection range concentration range is 0.5%-10% (mass fraction).

[0041] In other specific embodiments, the inclination angle of the return channel 43 is not less than 60°; a circulation valve 44 is fixed at the lower end of the inclination direction of the return channel 43; and the first end of the circulation pipe 37 is detachably connected to the circulation valve 44. The inclination arrangement of the return channel 43 at not less than 60° can minimize the flow resistance of the polishing fluid and ensure that the polishing fluid can circulate effectively.

[0042] In some other embodiments, the worktable 41 is cylindrical with a diameter of 600 mm, and can hold optical elements with a diameter of 100 mm to 600 mm.

[0043] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0044] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A polishing slurry circulation system for polishing large-aperture ultrahard optical components, characterized in that, include: A mixing tank (2) is provided, and there are multiple mixing tanks (2); each of the multiple mixing tanks (2) is provided with an inlet valve (27) and an outlet valve (26) at the bottom of its outer wall; the multiple mixing tanks (2) are respectively configured as a coarse polishing tank (21), a fine polishing tank (22) and a final polishing tank (23); the coarse polishing tank (21), the fine polishing tank (22) and the final polishing tank (23) are respectively filled with coarse polishing solution, fine polishing solution and final polishing solution; The clamping assembly (4) includes a worktable (41), a clamp (42) and a return channel (43); the clamp (42) is rotatably connected to the top surface of the worktable (41) to clamp the optical element (6); the return channel (43) is fixed to the outer wall of the worktable (41) and is arranged at an angle to receive the polishing liquid flowing downstream after polishing. The circulation assembly (3) includes a circulation pump (31), an outlet pipe (33), a polishing pipe (35), and a circulation pipe (37). The first end of the outlet pipe (33) can be detachably connected to the outlet valve (26) on the rough polishing barrel (21), fine polishing barrel (22), or final polishing barrel (23) according to the processing stage, and the second end is connected to the inlet of the circulation pump (31). The first end of the polishing pipe (35) is connected to the outlet of the circulation pump (31), and the second end is fixed with a nozzle (36) for spraying polishing liquid onto the surface of the optical element (6). The first end of the circulation pipe (37) is connected to the return tank (43), and the second end is detachably connected to the inlet valve (27) on the rough polishing barrel (21), fine polishing barrel (22), or final polishing barrel (23) used with the outlet pipe (33).

2. The polishing slurry circulation system for polishing large-aperture ultrahard optical elements according to claim 1, characterized in that, The mixing tank (2) includes a tank body, a tank cover and a stirrer (24); the top of the tank body is open; the tank cover can be detachably closed to the open end of the tank body; the body of the stirrer (24) is fixed to the top surface of the tank cover, and its stirring shaft passes through the tank cover and is inserted into the tank body.

3. The polishing slurry circulation system for polishing large-aperture ultrahard optical elements according to claim 2, characterized in that, The coarse polishing solution is composed of large-particle diamond / silicon carbide abrasive and a strong alkaline / acidic chemical solution, and the agitator (24) on the coarse polishing tank (21) adopts a high-speed stirring mode; the fine polishing solution is composed of fine cerium oxide / silicon dioxide abrasive and a neutral / weakly alkaline chemical solution, and the agitator (24) on the fine polishing tank (22) adopts a medium-speed stirring mode; the final polishing solution is composed of nano-colloidal silica and a surfactant, and the agitator (24) on the final polishing tank (23) adopts a low-speed stirring mode.

4. The polishing slurry circulation system for polishing large-aperture ultrahard optical elements according to claim 3, characterized in that, The volumes of the coarse blasting barrel (21), fine blasting barrel (22), and final blasting barrel (23) decrease sequentially.

5. A polishing slurry circulation system for polishing large-aperture ultrahard optical elements according to claim 1, characterized in that, The circulation assembly (3) further includes a filter (32) and a filter tube (34); the first end of the filter tube (34) is connected to the outlet of the circulation pump (31), and the second end is connected to the liquid inlet at the top of the filter (32); the first end of the polishing tube (35) is connected to the liquid outlet at the bottom of the filter (32).

6. A polishing slurry circulation system for polishing large-aperture ultrahard optical elements according to claim 5, characterized in that, It also includes a protective cabinet (1), and multiple mixing tanks (2), the circulating pump (31) and the filter (32) are all integrated into the inner bottom wall of the protective cabinet (1).

7. A polishing slurry circulation system for polishing large-aperture ultrahard optical elements according to claim 6, characterized in that, It also includes a concentration detector (5); each of the multiple stirring tanks (2) is equipped with a concentration detector (25) for detecting the concentration of the solution; the concentration detector (5) is fixed on the top surface of the protective cabinet (1) and electrically connected to the multiple concentration detectors (25).

8. A polishing slurry circulation system for polishing large-aperture ultrahard optical elements according to claim 1, characterized in that, The inclination angle of the reflux trough (43) is not less than 60°; a circulation valve (44) is fixed at the lower end of the reflux trough (43) in the inclination direction; the first end of the circulation pipe (37) is detachably connected to the circulation valve (44).

9. A polishing slurry circulation system for polishing large-aperture ultrahard optical elements according to claim 1, characterized in that, The nozzle (36) has a micro array nozzle in the spray section, the orifice diameter of which is 0.2 ~ 0.5 mm and the spray pressure is 0.1 ~ 0.3 bar.

10. A polishing slurry circulation system for polishing large-aperture ultrahard optical elements according to claim 1, characterized in that, The circulating pump (31) is a micro peristaltic pump or diaphragm pump with a flow rate range of 1-50 mL / min.

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