Processing method of large-aperture optical element

Abstract

The invention relates to a processing method of a large-aperture optical element, the processing method comprises the working procedures of rough grinding, accurate grinding, polishing, deterministic shaping and the like, rough grinding and accurate grinding are carried out on a five-axis milling and grinding machine tool, a flat sheet blank is clamped by adopting a plane bonding clamp, and the surface of the flat sheet blank is polished; the clamp and a hydraulic connector of a machine tool workbench are fastened, rough grinding and accurate grinding of the convex face of the part are completed, the convex face of the optical part is clamped through the spherical surface bonding milling clamp, and rough grinding and accurate grinding of the concave face are completed as well; in the polishing process, polishing is conducted on a numerical control polishing machine tool, an integrated edge covering clamp is adopted for clamping, the integrated edge covering clamp and a hydraulic connector of a machine tool workbench are fastened after clamping, and the polishing process is completed to remove a milled and ground surface damage layer; and in the deterministic shape correction procedure, an integrated edge covering clamp, a clamp handle and a hydraulic chuck of a mechanical arm polishing table are used for fastening, a mechanical arm is used for correcting and polishing the local surface shape of the optical element, and finally the purpose of improving the surface shape precision and the surface quality is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical equipment production, in particular, the present application relates to a processing method of large aperture optical element. BACKGROUND

[0002] At present, the processing method of optical element includes single-point diamond turning, die pressing method and milling and polishing, etc. However, for large aperture high precision aspheric optical processing, numerical control milling and polishing is usually used. The specific process includes rough grinding, fine grinding, polishing and deterministic modification, etc. The milling and grinding includes rough grinding and fine grinding. Rough grinding is to remove a large amount of material from the plane blank to obtain a basic spherical surface, and fine grinding is to obtain a better quality surface of the spherical aspheric surface. Polishing is a key process in optical element processing, which aims to remove the milling and grinding residual roughness and surface damage layer to obtain high quality surface precision and smoothness. Finally, local deterministic correction polishing process is carried out, and the mechanical arm is used to correct the local deterministic polishing of the optical element surface to achieve higher precision of the surface.

[0003] Unlike the batch production of small optical elements, large aperture optical elements require high precision, large aperture and heavy weight. Therefore, special fixtures are needed to clamp the optical elements during processing to ensure good positioning accuracy and inter-surface eccentricity requirements, and to achieve a stable and reliable processing process. Therefore, it is urgent to develop a high-precision, stable and reliable processing scheme and special fixture for the processing method of large aperture optical elements.

[0004] Because the curvature radius of each point on the aspheric surface is different, it cannot be polished like a plane and a sphere. It also cannot be ground and edged like a spherical optical element to ensure the eccentricity. For the processing technology of aspheric optical elements, the accuracy of the clamp can be relied on to ensure the eccentricity accuracy. During processing, a reference surface is usually milled and ground, and the clamp is used to ensure the part processing accuracy. For small and medium aperture optical lenses, the part is usually fixed by a plane or arc surface bonding clamp, and the outer circle runout is clamped to ensure the milling and polishing eccentricity. However, the processing method of large aperture optical elements is different from that of small and medium aperture optical parts. Because of its large aperture and heavy weight, it is difficult to clamp the part, which is easy to collapse, knock, slip and difficult to ensure the inter-surface eccentricity technical index, and the processing process is risky. For example, a single crystal germanium flat sheet with a diameter of φ300mm and a thickness of 70mm, the blank quality is more than 26kg. At this time, the blank cannot be manually clamped on the disc due to its large weight, and the eccentricity requirement cannot be guaranteed during processing. The processing of a blank with a diameter of φ400mm or more is even more difficult.

[0005] Therefore, traditional small- and medium-diameter aspherical optical processing techniques can no longer meet the processing requirements of large-diameter optical components, posing significant processing risks. To address issues such as clamping large-diameter optical components onto the mounting plate, component movement and detachment during processing, and ensuring high-quality positioning accuracy, specialized tooling fixtures for different processes were designed, and optical processing solutions were described to ensure greater stability, reliability, and safety in the processing of large-diameter optical components.

[0006] Chinese Patent Publication No. CN102909630A proposes a fixture for aspherical optical elements and a method for processing aspherical optical elements. However, it is only suitable for clamping and processing conventional small and medium-diameter optical blanks. It poses a high risk for clamping large-diameter and high-mass optical blanks, and the optical processing technology cannot meet the requirements for processing large-diameter and high-mass optical elements.

[0007] Chinese patent publication CN217914521U proposes a fixture for polishing large-diameter optical elements, which can hold optical elements relatively stably. However, it does not consider the scenario of holding large-diameter optical elements in milling process, and does not clearly describe the optical processing method of the polishing fixture. Summary of the Invention

[0008] To overcome the problems existing in the background technology, this invention discloses a processing method for large-aperture optical components. The processing method includes: using a planar bonding milling fixture and a spherical bonding milling fixture to clamp a flat blank and perform rough grinding to form a spherical surface on a five-axis CNC milling machine; using an integrated edge-binding fixture to clamp the part and perform fine grinding of the aspherical surface on a five-axis CNC milling machine; using an integrated edge-binding fixture to clamp the part and perform overall polishing on a CNC polishing machine; and using an integrated edge-binding fixture to clamp the part and perform local deterministic shaping on a robotic arm polishing system. This invention addresses problems such as clamping large-aperture optical components onto the mounting plate, part movement and detachment during processing, and ensuring high-quality positioning accuracy by designing special tooling fixtures for different processes and describing optical processing schemes, ensuring greater stability, reliability and safety in the processing of large-aperture optical components.

[0009] Different tooling fixtures can be adapted to each processing step of the blank. The structure is simple and reliable, which can better reduce processing risks and improve stability.

[0010] To achieve the above objectives, the present invention is implemented through the following technical solution: The method for fabricating the large-aperture optical element is characterized by comprising the following steps: 1) Rough grinding convex surface forming process: The rough grinding convex surface forming process uses a flat bonding milling fixture and a five-axis CNC milling machine table to complete the rough grinding of the convex spherical surface of the flat blank. After rough grinding, a large-diameter part with a rough convex spherical radius is obtained. 2) Rough grinding concave surface forming process: For large-diameter parts with rough convex surface spherical radius, use a spherical bonding milling fixture to fasten to the hydraulic joint of the five-axis CNC milling machine table and complete the rough grinding of the concave spherical surface of the flat blank. After rough grinding, a large-diameter spherical part with rough radius is obtained. 3) Fine grinding of aspherical surfaces: For large-diameter spherical parts with rough radius opening, use an integrated edge clamping fixture to fasten the part to the hydraulic joint of the five-axis CNC milling machine table and complete the fine grinding of the convex or concave aspherical surface of the part to obtain the finely ground large-diameter aspherical optical parts. 4) Pre-polishing process: The aspherical large-diameter optical parts that have been finely ground are clamped in an integrated edge-binding fixture and polished as a whole on a CNC polishing machine. The fixture is hydraulically fastened to the CNC polishing machine table and the convex or concave aspherical surface polishing of the aspherical large-diameter optical parts is completed. 5) Surface shape inspection: Perform surface shape inspection on the polished large-diameter optical components. If the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV, the surface shape error is judged to be small. Conversely, large-aperture optical components with large surface shape errors undergo pre-polishing again until the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV. 6) Local deterministic reshaping process: For large-aperture optical components with surface accuracy RMS≤0.1um and surface finish reaching level IV, a robotic arm polishing system is used to perform local deterministic reshaping polishing on the surface of the large-aperture optical components until the surface accuracy RMS≤20nm, and then proceed to the next process.

[0011] As a preferred option: in steps 1) and 2), the coarse grinding wheel used in the coarse grinding operation is a bronze-bonded diamond grinding wheel with a grit size of 80# to 280#. The spherical forming process is carried out by casting. The diameter of the grinding wheel is at least half the diameter of the blank, the radius of the grinding wheel fillet is 2.5 mm, the grinding wheel speed is 3000-6000 RPM, and the feed speed is 0.1-0.5 mm / min.

[0012] As a preferred embodiment: In step 3), the grinding wheel used for fine grinding is a resin-bonded diamond grinding wheel with a grit size of at least 800 mesh, a removal amount of at least 3 to 7 filaments per cut, a grinding wheel inclination angle of 20 to 45 degrees, a grinding wheel diameter at least half the diameter of the blank, a fillet radius of 2.5 mm, a spiral trajectory feeding method, a pitch of 0.05 to 0.12 mm, and a grinding wheel linear speed of not less than 3500 mm / min.

[0013] Preferably, in steps 4) and 5), the CNC polishing machine tool uses an airbag-type polishing head, the polishing auxiliary materials are polyurethane polishing pads and cerium oxide polishing powder, the polishing head speed is ≥400r / min, the workpiece speed is ≥300r / min, the polishing time is at least 4800s, the polishing head air pressure is ≥0.8bar, the polishing surface accuracy reaches RMS≤0.1um, and the surface finish reaches level IV.

[0014] As a preferred embodiment: In step 6), the bottom end of the robotic arm polishing system is provided with a polishing head, which is a rubber polishing head, and the polishing auxiliary materials are a polyurethane polishing pad and cerium oxide polishing powder. The polishing head rotation speed is ≥600r / min, the polishing head movement trajectory is a grid trajectory, the polishing pressure is ≤15N, and the polishing time for each round is set to at least 1800s.

[0015] Preferably, the planar bonding milling fixture includes: a planar bonding milling fixture handle, a planar bonding milling fixture base, a planar bonding milling fixture lifting ring, a screw stop bar, and a thick rubber buffer pad; The planar bonding milling fixture is fastened to the planar bonding milling fixture base by a planar bonding milling fixture handle and a planar bonding milling fixture base through circumferentially distributed circumferential positioning screw holes. The planar bonding milling fixture base is located at the upper end of the planar bonding milling fixture handle. A screw stop is installed on the upper end face of the planar bonding milling fixture base. The hole spacing of the circumferential positioning screw holes is determined by the blank size. The gap between the screw stop and the blank is 0.8-1.5mm. A thick rubber buffer pad is installed between the screw stop and the flat blank. The upper surface of the planar bonding milling fixture substrate is uniformly distributed with 6 to 8 bonding ring grooves, each 10 mm wide and 2 mm deep. The flat blank is firmly bonded to the planar bonding milling fixture substrate by adhesive, and the circumferential runout of the blank during the bonding process is <0.02 mm. The planar bonding milling fixture base has symmetrically arranged lifting ring mounting holes on its side corners. The lifting ring mounting holes are M10 screw holes. The upper surface of the planar bonding milling fixture base has an exhaust groove. The lifting ring of the planar bonding milling fixture is connected to the M10 screw hole on the side of the planar bonding milling fixture base, and is installed with the assistance of a hydraulic lifting device; The planar bonding milling fixture handle includes: a columnar joint, a circumferential countersunk hole, a tool relief groove, and an upper plane of the planar bonding milling fixture handle; the tool relief groove is provided on the bottom surface of the planar bonding milling fixture handle, the columnar joint is inserted into the tool relief groove, and the circumferential countersunk hole is provided through the bottom surface of the planar bonding milling fixture handle.

[0016] Preferably, the spherical bonding milling fixture includes: a spherical bonding milling fixture handle, a lifting table, and a spherical bonding milling fixture base; The spherical bonding milling fixture handle is fastened to the spherical bonding milling fixture base through circumferentially distributed circumferential positioning screw holes, and the spherical bonding milling fixture base is located at the upper end of the spherical bonding milling fixture handle; the top surface of the lifting platform is provided with a lifting hole, which is an M8 screw hole, and the lifting platform is symmetrically installed at both ends of the spherical bonding milling fixture base through the lifting hole. The outer side of the lifting platform is provided with a fixing countersunk hole, and a hydraulic lifting device is used for auxiliary installation; The upper surface of the spherical bonding milling fixture base is an arc surface for bonding, and the radius of the bonding arc surface is the same as that of the convex surface of the blank. The optical component is firmly bonded to the upper surface of the spherical bonding milling fixture base with adhesive. The bonding process ensures that the circumferential runout of the blank is <0.02mm. Two φ5mm side vent holes are symmetrically opened on the side of the spherical bonding milling fixture base. The spherical bonding milling fixture handle includes: a columnar joint, a circumferential countersunk hole, a tool relief groove, and a planar bonding milling fixture handle upper surface; the tool relief groove is provided on the bottom surface of the planar bonding milling fixture handle, the columnar joint is inserted into the tool relief groove, and the circumferential countersunk hole is provided through the bottom surface of the planar bonding milling fixture handle.

[0017] Preferably, the integrated edge-binding clamp includes: an integrated edge-binding clamp handle, an integrated edge-binding clamp lifting ring, and an integrated edge-binding clamp base; the integrated edge-binding clamp handle is fastened to the integrated edge-binding clamp base through 6 circumferentially distributed circumferential positioning screw holes, and the integrated edge-binding clamp base is located at the upper end of the integrated edge-binding clamp handle; the integrated edge-binding clamp base has symmetrically arranged integrated edge-binding clamp lifting ring mounting holes on its side corners, and the integrated edge-binding clamp lifting ring mounting holes are M10 screw holes; The upper surface of the inner cavity of the integrated edge-binding fixture has four weight-reducing grooves. The weight-reducing grooves are triangular and their size is adapted to the size of the integrated edge-binding fixture. The integrated edge-binding fixture base has four φ5mm bottom vent holes evenly distributed around its bottom circumference; the diameter of the bonding surface of the integrated edge-binding fixture base is 0.1mm smaller than the outer diameter of the optical component; the bottom surface of the optical component is placed at the step of the bonding surface of the integrated edge-binding fixture base; the side of the optical component is firmly bonded to the bonding surface of the integrated edge-binding fixture base; the bonding process ensures that the circumferential runout of the blank is less than 0.1mm. The integrated edge-binding clamp base has two arc-shaped transition slots symmetrically opened on its circumference for clamping the hand clamp with the part. When clamping with the concave surface, it ensures that the arc height of the convex surface of the part does not interfere with the integrated edge-binding clamp base. The lifting ring of the integrated edge-binding clamp is connected to the screw hole on the side of the integrated edge-binding clamp base, and the installation is assisted by a hydraulic lifting device. The integrated edge-binding fixture handle includes: a columnar connector, a circumferential countersunk hole, a tool relief groove, and a flat surface of the planar bonding milling fixture handle; the tool relief groove is provided on the bottom surface of the planar bonding milling fixture handle, the columnar connector is inserted into the tool relief groove, and the circumferential countersunk hole is provided through the bottom surface of the planar bonding milling fixture handle.

[0018] The beneficial effects of this invention are as follows: This invention provides a processing solution and dedicated fixture design suitable for large-aperture, high-precision aspherical optical components, enabling high-precision processing and manufacturing of large-aperture spherical and aspherical optical components. The overall process includes rough grinding of the spherical surface, fine grinding of the aspherical surface, pre-polishing, and localized definitive shaping processes.

[0019] The processing method includes: using a planar bonding milling fixture and a spherical bonding milling fixture to clamp the flat blank and perform rough grinding to form a spherical surface on a five-axis CNC milling machine; using an integrated edge-binding fixture to clamp the part and perform fine grinding to form an aspherical surface on a five-axis CNC milling machine; using an integrated edge-binding fixture to clamp the part and perform overall polishing on a CNC polishing machine; and using an integrated edge-binding fixture to clamp the part and perform local deterministic shaping on a robotic arm polishing system. This invention addresses issues such as clamping large-aperture optical components onto the mounting plate, component movement and detachment during processing, and ensuring high-quality positioning accuracy. It designs special tooling fixtures for different processes and describes optical processing schemes to ensure greater stability, reliability, and safety in the processing of large-aperture optical components. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the fabrication process of large-aperture optical components. Figure 2 A schematic diagram of the clamping structure of a planar bonding milling fixture; Figure 3 A schematic diagram of the spherical bonding milling fixture. Figure 4 A schematic diagram of the integrated edge-binding clamping structure; Figure 5 Schematic diagrams of the structure of planar bonded milling jig handles, spherical bonded milling jig handles, and integrated edge-wrapping jig handle components; Figure 6 This is a schematic diagram of the structure of a planar bonding milling fixture substrate; Figure 7 A schematic diagram of the structure of the spherical bonding milling fixture substrate; Figure 8 A schematic diagram of the structure of the integrated edge-binding clamp base; Figure 9 Exploded view of the planar bonding milling fixture assembly; Figure 10 Exploded view of the spherical bonding milling fixture assembly; Figure 11Exploded view of the integrated edge-binding fixture assembly; Figure 12 A schematic diagram of an integrated edge-binding fixture-robotic arm polishing process; In the figure, 1 is a planar bonding milling fixture, 2 is a flat optical component blank, 3 is a spherical bonding milling fixture, 4 is a convex optical component blank, 5 is an integrated edge-binding fixture, 6 is an optical component blank with pre-cut radius, 7 is a columnar joint, 8 is a circumferential countersunk hole, 9 is a relief groove, 10 is the upper plane of the fixture handle, 11 is the upper plane of the planar bonding milling fixture base, 12 is a circumferential positioning screw hole, 13 is a bonding ring groove, 14 is a lifting eye of the planar bonding milling fixture, 14-1 is a lifting eye mounting hole of the planar bonding milling fixture, 15 is a vent groove, and 16 is a side vent hole. 17. Lifting hole; 18. Adhesive arc surface; 19. Fixing countersunk hole; 20. Integrated edge-binding clamp lifting ring; 20-1. Integrated edge-binding clamp lifting ring mounting hole; 21. Weight reduction groove; 22. Clamp side; 23. Adhesive surface; 24. Bottom vent hole; 25. Transition groove; 26. Rubber buffer pad; 27. Screw stop; 28. Flat bonding milling clamp handle; 29. ​​Lifting platform; 30. Spherical bonding milling clamp handle; 31. Integrated edge-binding clamp handle; 32. Mechanical arm polishing system; 33. Polishing head; 34. Large-diameter optical element. Detailed Implementation

[0021] To make the above objectives, technical solutions, and beneficial effects clearer and more explicit, the present invention will be described in detail below with reference to the accompanying drawings.

[0022] To make the above objectives, technical solutions, and beneficial effects clearer and more explicit, the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0023] like Figure 1 As shown, the method for fabricating the large-aperture optical element is characterized by comprising the following steps: 1) Rough grinding convex surface forming process: The rough grinding convex surface forming process uses a flat bonding milling fixture 1 and a five-axis CNC milling machine worktable to complete the rough grinding of the convex spherical surface of the flat blank. After rough grinding, a large-diameter part with a rough convex spherical radius is obtained. 2) Rough grinding concave surface forming process: For large-diameter parts with rough convex surface spherical radius, use spherical bonding milling fixture 3 to fasten to the hydraulic joint of the five-axis CNC milling machine table and complete the rough grinding of the concave spherical surface of the flat blank. After rough grinding, a large-diameter spherical part with rough radius is obtained. 3) Fine grinding of aspherical surfaces: The spherical large-diameter parts with rough radius have been fixed by an integrated edge clamping fixture 5 and a hydraulic connector of the five-axis CNC milling machine table, and the convex or concave aspherical surface of the parts is finely ground to obtain finely ground aspherical large-diameter optical parts. 4) Pre-polishing process: The aspherical large-diameter optical parts that have been finely ground are clamped in an integrated edge clamping fixture 5 and polished as a whole on a CNC polishing machine. The fixture is fastened to the hydraulic joint of the CNC polishing machine table and the convex or concave aspherical surface polishing of the aspherical large-diameter optical parts is completed. 5) Surface shape inspection: The surface shape of the polished large-diameter optical element 34 is inspected. If the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV, the surface shape error is judged to be small. Conversely, large-aperture optical elements 34 with large surface shape errors undergo pre-polishing again until the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV. 6) Local deterministic reshaping process: For large-aperture optical elements 34 with surface accuracy RMS≤0.1um and surface finish reaching level IV, the surface of the large-aperture optical elements is locally reshaping and polished using a robotic arm polishing system 32 until the surface accuracy RMS≤20nm, and then proceeds to the next process.

[0024] As a preferred option: in steps 1) and 2), the coarse grinding wheel used in the coarse grinding operation is a bronze-bonded diamond grinding wheel with a grit size of 80# to 280#. The spherical forming process is carried out by casting. The diameter of the grinding wheel is at least half the diameter of the blank, the radius of the grinding wheel fillet is 2.5 mm, the grinding wheel speed is 3000-6000 RPM, and the feed speed is 0.1-0.5 mm / min.

[0025] like Figures 1-12 As shown, the planar bonding milling fixture 1 includes: a planar bonding milling fixture handle 28, a planar bonding milling fixture 1 base, a planar bonding milling fixture lifting ring 14, a screw stop bar 27, and a thick rubber buffer pad 26; The planar bonding milling fixture 1 is fastened to the base of the planar bonding milling fixture 1 by the fixture handle 28 through circumferentially distributed circumferential positioning screw holes 12. The base of the planar bonding milling fixture 1 is located at the upper end of the fixture handle 28. A screw stop 27 is installed on the upper end face of the base of the planar bonding milling fixture 1. The hole spacing of the circumferential positioning screw holes 12 is determined by the blank size, and the gap between the screw stop 27 and the blank is 0.8-1.5mm. A thick rubber buffer pad 26 is installed between the screw stop 27 and the flat blank. The upper surface of the substrate of the planar bonding milling fixture 1 has 6-8 bonding ring grooves 13 with a width of 10mm and a depth of 2mm evenly distributed. The flat blank is firmly bonded to the substrate of the planar bonding milling fixture 1 with adhesive. During the bonding process, the circumferential runout of the blank is <0.02mm. The side corners of the substrate of the planar bonding milling fixture 1 are symmetrically provided with planar bonding milling fixture lifting ring mounting holes 14-1. The planar bonding milling fixture lifting ring mounting holes 14-1 are M10 screw holes. The upper surface 11 of the planar bonding milling fixture substrate is provided with venting grooves 15. The lifting ring 14 of the planar bonding milling fixture is connected to the M10 screw hole on the side of the base of the planar bonding milling fixture 1, and is installed with the assistance of a hydraulic lifting device; the planar bonding milling fixture handle 28 includes: a columnar joint 7, a circumferential countersunk hole 8, a tool relief groove 9, and an upper surface of the planar bonding milling fixture handle 28; the tool relief groove 9 is provided on the bottom surface of the planar bonding milling fixture handle 28, the columnar joint 7 is inserted into the tool relief groove 9, and the circumferential countersunk hole 8 is provided through the bottom surface of the planar bonding milling fixture handle 28.

[0026] The spherical bonding milling fixture 3 includes: a spherical bonding milling fixture handle 30, a lifting platform 29, and a spherical bonding milling fixture 3 base. The spherical bonding milling fixture handle 30 is fastened to the spherical bonding milling fixture 3 base through circumferentially distributed circumferential positioning screw holes 12, and the spherical bonding milling fixture 3 base is located at the upper end of the spherical bonding milling fixture handle 30. The top surface of the lifting platform 29 is provided with a through-hole 17, which is an M8 screw hole. The lifting platform 29 is symmetrically installed at both ends of the spherical bonding milling fixture 3 base through the lifting hole 17. The outer side of the lifting platform 29 is provided with a fixing countersunk hole 19, and a hydraulic lifting device is used for auxiliary installation. The spherical bonding milling fixture 3 The upper surface of the substrate has an arc surface 18 for bonding. The arc surface 18 has the same radius as the convex surface of the blank. The optical component is firmly bonded to the upper surface of the substrate of the spherical bonding milling fixture 3 by an adhesive. The bonding process ensures that the circumferential runout of the blank is <0.02mm. The spherical bonding milling fixture 3 has two symmetrical φ5mm side vent holes 16 on its side. The spherical bonding milling fixture handle 30 includes: a columnar joint 7, a circumferential countersunk hole 8, a tool relief groove 9, and a planar bonding milling fixture handle 28. The tool relief groove 9 is located on the bottom surface of the planar bonding milling fixture handle 28. The columnar joint 7 is inserted into the tool relief groove 9, and the circumferential countersunk hole 8 is located through the bottom surface of the planar bonding milling fixture handle 28.

[0027] The integrated edge-binding clamp 5 includes: an integrated edge-binding clamp handle 31, an integrated edge-binding clamp lifting ring 20, and an integrated edge-binding clamp base 5. The integrated edge-binding clamp handle 31 is fastened to the integrated edge-binding clamp base 5 by six circumferentially distributed circumferential positioning screw holes 12, and is connected to the integrated edge-binding clamp base 5. The integrated edge-binding clamp base 5 is located at the upper end of the integrated edge-binding clamp handle 31. The integrated edge-binding clamp base 5 has symmetrically arranged integrated edge-binding clamp lifting ring mounting holes 2 on its side corners. 0-1, the mounting hole 20-1 of the integrated edge-binding clamp is an M10 screw hole; four weight-reducing grooves 21 are opened on the upper surface of the inner cavity of the integrated edge-binding clamp 5, the weight-reducing grooves 21 are triangular grooves, and the size of the weight-reducing grooves 21 is adapted to the size of the integrated edge-binding clamp 5; four φ5mm bottom vent holes 24 are evenly distributed on the circumference of the bottom surface of the integrated edge-binding clamp 5; the diameter of the bonding surface 23 of the integrated edge-binding clamp 5 is 0.1mm smaller than the outer diameter of the optical component, and the optical component... The bottom surface of the component is placed at the step of the bonding surface 23 of the integrated edge-binding clamp 5. The side of the optical component is firmly bonded to the bonding surface 23 of the integrated edge-binding clamp 5, ensuring that the circumferential runout of the blank is less than 0.1mm during the bonding process. The integrated edge-binding clamp 5 has two symmetrically opened arc-shaped transition grooves 25 on its circumference for clamping the component with the hand clamp. When clamping with the concave surface, it ensures that the arc height of the convex surface of the component does not interfere with the integrated edge-binding clamp 5. The integrated edge-binding clamp 5 has two arc-shaped transition grooves 25 on its circumference for clamping the component with the hand clamp. The edge clamp lifting ring 20 is connected to the screw hole on the side of the integrated edge clamp 5 base body, and is installed with the assistance of a hydraulic lifting device; the integrated edge clamp handle 31 includes: a columnar joint 7, a circumferential countersunk hole 8, a tool relief groove 9, and a flat surface of the flat bonding milling clamp handle 28; the tool relief groove 9 is provided on the bottom surface of the flat bonding milling clamp handle 28, the columnar joint 7 is inserted into the tool relief groove 9, and the circumferential countersunk hole 8 is provided through the bottom surface of the flat bonding milling clamp handle 28.

[0028] Example 1: The processing method includes the following steps: 1) Rough grinding and convex surface forming process: For flat blanks of optical materials, the aspherical process first requires milling the optimal spherical surface corresponding to the aspherical surface. The flat blank is clamped using a planar bonding milling fixture 1. The planar bonding milling fixture 1 is fastened to the hydraulic joint of the worktable of the five-axis CNC milling machine and the rough grinding of the convex spherical surface of the part is completed. The planar bonding milling fixture 1 is fastened to the base of the planar bonding milling fixture 1 by the fixture handle 28 through circumferential positioning screw holes 12. The circumferential positioning screw holes 12 are M6 screws. Multiple layers of circumferential positioning screw holes 12 are evenly distributed around the upper surface of the base of the planar bonding milling fixture 1. The hole spacing is determined by the blank size. Screw stops 27 are installed in the screw holes around the blank disc. A 0.5mm rubber buffer pad 26 is inserted between the screw stops and the blank part to prevent the part from moving during the machining process. The upper surface of the base of the planar bonding milling fixture 1 has 6 bonding ring grooves 10mm wide and 1mm deep evenly distributed. The optical blank disc is firmly bonded to the fixture base by adhesive. The adhesive remains in the bonding ring grooves 13 to increase the bonding force. The main component of the adhesive is asphalt, and the circumferential runout of the blank during the bonding process is 0.02mm. Two sets of planar bonding milling fixture lifting ring mounting holes 14-1 are symmetrically distributed on the side of the base of the planar bonding milling fixture 1. The planar bonding milling fixture lifting ring 14 is connected to the planar bonding milling fixture lifting ring mounting hole 14-1 position on the side of the base of the planar bonding milling fixture 1. The lifting rope is connected through the planar bonding milling fixture lifting ring 14. The hydraulic lifting device is used for auxiliary installation to ensure that the planar bonding milling fixture 1 is safely and reliably clamped onto the worktable of the five-axis CNC milling machine. The planar bonding milling fixture 1 and the worktable of the five-axis CNC milling machine are used to complete the rough grinding of the convex spherical surface of the flat blank. After rough grinding, a large-diameter part with a rough convex spherical radius is obtained.

[0029] 2) Rough grinding and concave surface forming process: For large-diameter parts with a rough convex spherical radius already formed, a spherical bonding milling fixture 3 is used for clamping. The spherical bonding milling fixture 3 is fastened to the hydraulic connector of the five-axis CNC milling machine table, and the rough grinding of the concave spherical surface of the part is completed. The spherical bonding milling fixture 3 is fastened by the spherical bonding milling fixture handle 30, the lifting table 29, and the base of the spherical bonding milling fixture 3 through the circumferential positioning screw holes 12. The convex surface of the optical component is firmly bonded to the arc surface of the spherical bonding milling fixture 3 substrate using an adhesive. The main component of the adhesive is asphalt. The bonding process ensures that the circumferential runout of the blank is 0.02mm. Two φ5 side vent holes 16 are symmetrically opened on the side of the spherical bonding milling fixture 3 for easy venting. Two sets of lifting holes 17 are symmetrically opened on the substrate of the spherical bonding milling fixture 3. The lifting holes 17 are M8 screw holes. The lifting table 29 is connected to the two sides of the substrate of the spherical bonding milling fixture 3 substrate by screws. Each lifting table 29 has two countersunk holes 19 for fixing to facilitate the binding of the lifting rope. The lifting rope is connected to the lifting table 29, and the hydraulic lifting device is used for auxiliary installation to ensure that the spherical bonding milling fixture 3 is safely and reliably clamped onto the worktable of the five-axis CNC milling machine. The rough grinding wheel is a bronze-bonded diamond grinding wheel with a grit size of 80#. The spherical forming is performed using the forming method. The diameter of the grinding wheel is at least half the diameter of the blank, the fillet radius is 2.5mm, the grinding wheel speed is 3000RPM, and the feed rate is 0.1mm / min. For large-diameter parts with a rough convex spherical radius, the spherical bonding milling jig 3 is used to fasten the worktable of the five-axis CNC milling machine with a hydraulic connector to complete the rough grinding of the concave spherical surface of the flat blank. After rough grinding, a large-diameter spherical part with a rough radius is obtained.

[0030] 3) Fine grinding of aspherical surfaces: For large-diameter spherical parts with rough radius already completed, the aspherical surface finishing process uses an integrated edge-binding fixture 5 for clamping. The fixture is hydraulically fastened to the worktable of the five-axis CNC milling machine and completes the finishing of the convex or concave aspherical surface of the part. The integrated edge-binding fixture 5 is fastened to the integrated edge-binding fixture shank 31 and the integrated edge-binding fixture 5 base by circumferential positioning screws. The sides of the large-diameter optical components are bonded to the inner side of the integrated edge clamp 5 substrate using optical glass adhesive. When the convex surface of the component is facing down, the height of the side of the integrated edge clamp 5 must exceed the arc height of the convex surface to avoid interference between the component and the integrated edge clamp 5. The lifting rope is connected to the lifting ring 20 of the integrated edge clamp, and the installation is assisted by a hydraulic lifting device. The bottom surface of the integrated edge clamp 5 has weight-reducing grooves 21 evenly distributed to ensure the rigidity of the integrated edge clamp 5 while reducing weight. The bottom vent holes 24 are evenly distributed on the bottom surface of the integrated edge clamp 5. The integrated edge clamp 5 has two transition slots 25 symmetrically distributed around its circumference to facilitate the hand support of the component for clamping on the upper plate. The lifting rope is connected to the lifting ring 20 of the integrated edge clamp, and the installation is assisted by a hydraulic lifting device. Then, the large-diameter blank is milled and shaped by a five-axis CNC milling machine. The precision grinding wheel is a resin-bonded diamond grinding wheel with a grit size of 800 mesh. Each cut removes 3 microns of material. The grinding wheel inclination angle is 20 degrees, the grinding wheel diameter is greater than half the diameter of the blank, the fillet radius is 2.5 mm, and a spiral trajectory feed method is adopted with a pitch of 0.05 mm and a grinding wheel linear speed of 3500 mm / min.

[0031] 4) Pre-polishing process: For large-diameter aspherical optical components that have undergone fine grinding, polishing can remove the surface damage layer and achieve a better overall surface accuracy. This process does not change the fixture; the pre-polishing still uses the integrated edge-binding fixture 5. The integrated edge-binding fixture 5 is hydraulically connected to the worktable of the five-axis CNC polishing machine and completes the convex or concave aspherical surface polishing of the part. The pre-polishing process uses an airbag-type polishing head 33, with polyurethane polishing pads and cerium oxide polishing powder as polishing aids. The polishing head 33 rotates at 400 r / min, the workpiece rotates at 300 r / min, the polishing time is 4800 s, and the air pressure of the polishing head 33 is 0.8 bar.

[0032] 5) Surface shape inspection: The surface shape of the polished large-diameter optical element 34 is inspected. If the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV, the surface shape error is judged to be small. Conversely, large-aperture optical elements 34 with large surface shape errors undergo pre-polishing again until the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV. 6) Localized shaping process: For large-aperture optical elements 34, after achieving an overall surface accuracy RMS ≤ 0.1µm and a surface finish of level IV, a robotic arm polishing system 32 is used to perform localized deterministic correction polishing on the surface of the large-aperture optical elements to achieve higher surface accuracy requirements, with an RMS ≤ 20nm. This process does not change the fixture; the integrated edge-wrapping fixture 5 is still used for localized deterministic polishing. The integrated edge-wrapping fixture 5 is fastened to the hydraulic chuck of the robotic arm polishing table to complete the final surface correction process of the part, processing it to an RMS ≤ 20nm before proceeding to the next process. A polishing head 33 is located at the bottom of the robotic arm polishing system 32. The polishing head 33 is a rubber polishing head, and the polishing materials are a polyurethane polishing pad and cerium oxide polishing powder. The polishing head 33 rotates at 600 r / min, its movement trajectory is a grid trajectory, the polishing pressure is 15N, and the polishing time for each round is set to at least 1800s.

[0033] Example 2: The processing method includes the following steps: 1) Rough grinding and convex surface forming process: For flat blanks of optical materials, the aspherical process first requires milling the optimal spherical surface corresponding to the aspherical surface. The flat blank is clamped using a planar bonding milling fixture 1. The planar bonding milling fixture 1 is fastened to the hydraulic joint of the worktable of the five-axis CNC milling machine and the rough grinding of the convex spherical surface of the part is completed. The planar bonding milling fixture 1 is fastened to the base of the planar bonding milling fixture 1 by the fixture handle 28 through circumferential positioning screw holes 12. The circumferential positioning screw holes 12 are M6 screws. Multiple layers of circumferential positioning screw holes 12 are evenly distributed around the upper surface of the base of the planar bonding milling fixture 1. The hole spacing is determined by the blank size. Screw stops 27 are installed in the screw holes around the blank disc. A 1mm rubber buffer pad 26 is inserted between the screw stops and the blank part to prevent the part from moving during processing. The upper surface of the base of the planar bonding milling fixture 1 has 8-width, 10mm wide, and 1mm deep bonding ring grooves 13 evenly distributed. The optical blank disc is firmly bonded to the fixture base by adhesive. The adhesive remains in the bonding ring grooves 13 to increase the bonding force. The main component is asphalt, and the circumferential runout of the blank during the bonding process is 0.015mm. Two sets of planar bonding milling fixture lifting ring mounting holes 14-1 are symmetrically distributed on the side of the base of the planar bonding milling fixture 1. The planar bonding milling fixture lifting ring 14 is connected to the planar bonding milling fixture lifting ring mounting hole 14-1 on the side of the base of the planar bonding milling fixture 1. The lifting rope is connected through the planar bonding milling fixture lifting ring 14. The hydraulic lifting device is used for auxiliary installation to ensure that the planar bonding milling fixture 1 is safely and reliably clamped onto the worktable of the five-axis CNC milling machine. The planar bonding milling fixture 1 and the worktable of the five-axis CNC milling machine are used to complete the rough grinding of the convex spherical surface of the flat blank. After rough grinding, a large-diameter part with a rough convex spherical radius is obtained.

[0034] 2) Rough grinding and concave surface forming process: For large-diameter parts with a rough convex spherical radius already formed, a spherical bonding milling fixture 3 is used for clamping. The spherical bonding milling fixture 3 is fastened to the hydraulic connector of the five-axis CNC milling machine table, and the rough grinding of the concave spherical surface of the part is completed. The spherical bonding milling fixture 3 is fastened by the spherical bonding milling fixture handle 30, the lifting table 29, and the base of the spherical bonding milling fixture 3 through the circumferential positioning screw holes 12. The convex surface of the optical component is firmly bonded to the arc surface of the spherical bonding milling fixture 3 substrate using an adhesive. The main component of the adhesive is asphalt. The bonding process ensures that the circumferential runout of the blank is 0.015mm. Two φ5 side vent holes 16 are symmetrically opened on the side of the spherical bonding milling fixture 3 for easy venting. Two sets of lifting holes 17 are symmetrically opened on the substrate of the spherical bonding milling fixture 3. The lifting holes 17 are M8 screw holes. The lifting table 29 is connected to the two sides of the substrate of the spherical bonding milling fixture 3 substrate by screws. Each lifting table 29 has two countersunk holes 19 for fixing to facilitate the binding of the lifting rope. The lifting rope is connected to the lifting table 29, and the hydraulic lifting device is used for auxiliary installation to ensure that the spherical bonding milling fixture 3 is safely and reliably clamped onto the worktable of the five-axis CNC milling machine. The rough grinding wheel is a bronze-bonded diamond grinding wheel with a grit size of 280#. The spherical forming is performed using the forming method. The diameter of the grinding wheel is at least half the diameter of the blank, the fillet radius is 2.5mm, the grinding wheel speed is 6000RPM, and the feed rate is 0.5mm / min. For large-diameter parts with rough convex spherical radius, the spherical bonding milling jig 3 is used to fasten the worktable of the five-axis CNC milling machine with a hydraulic connector to complete the rough grinding of the concave spherical surface of the flat blank. After rough grinding, a large-diameter spherical part with rough radius is obtained.

[0035] 3) Fine grinding of aspherical surfaces: For large-diameter spherical parts with rough radius already completed, the aspherical surface finishing process uses an integrated edge-binding fixture 5 for clamping. The fixture is hydraulically fastened to the worktable of the five-axis CNC milling machine and completes the finishing of the convex or concave aspherical surface of the part. The integrated edge-binding fixture 5 is fastened to the integrated edge-binding fixture shank 31 and the integrated edge-binding fixture 5 base by circumferential positioning screws. The sides of the large-diameter optical components are bonded to the inner side of the integrated edge clamp 5 substrate using optical glass adhesive. When the convex surface of the component is facing down, the height of the side of the integrated edge clamp 5 must exceed the arc height of the convex surface to avoid interference between the component and the integrated edge clamp 5. The lifting rope is connected to the lifting ring 20 of the integrated edge clamp, and the installation is assisted by a hydraulic lifting device. The bottom surface of the integrated edge clamp 5 has weight-reducing grooves 21 evenly distributed to ensure the rigidity of the integrated edge clamp 5 while reducing weight. The bottom vent holes 24 are evenly distributed on the bottom surface of the integrated edge clamp 5. The integrated edge clamp 5 has two transition slots 25 symmetrically distributed around its circumference to facilitate the hand support of the component for clamping on the upper plate. The lifting rope is connected to the lifting ring 20 of the integrated edge clamp, and the installation is assisted by a hydraulic lifting device. Then, the large-diameter blank is milled and shaped by a five-axis CNC milling machine. The fine grinding wheel is a resin-bonded diamond grinding wheel with a grit size of at least 800 mesh. Each cut removes 7 microns of material. The grinding wheel inclination angle is 45 degrees. The grinding wheel diameter is at least half the diameter of the blank. The fillet radius is 2.5 mm. It adopts a spiral trajectory feeding method with a pitch of 0.12 mm and a grinding wheel linear speed of 4000 mm / min.

[0036] 4) Pre-polishing process: For large-diameter aspherical optical components that have undergone fine grinding, polishing can remove the surface damage layer and achieve a better overall surface accuracy. This process does not change the fixture; the pre-polishing still uses the integrated edge-binding fixture 5. The integrated edge-binding fixture 5 is hydraulically connected to the worktable of the five-axis CNC polishing machine and completes the convex or concave aspherical surface polishing of the part. The pre-polishing process uses an airbag-type polishing head 33, with polyurethane polishing pads and cerium oxide polishing powder as polishing aids. The polishing head 33 rotates at 500 r / min, the workpiece rotates at 400 r / min, the polishing time is 5000 s, and the air pressure of the polishing head 33 is 1.0 bar.

[0037] 5) Surface shape inspection: The surface shape of the polished large-diameter optical element 34 is inspected. If the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV, the surface shape error is judged to be small. Conversely, large-aperture optical elements 34 with large surface shape errors undergo pre-polishing again until the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV. 6) Localized shaping process: For large-aperture optical elements 34, after achieving an overall surface accuracy RMS ≤ 0.1µm and a surface finish of level IV, a robotic arm polishing system 32 is used to perform localized deterministic correction polishing on the surface of the large-aperture optical elements to achieve a higher surface accuracy requirement, with an RMS ≤ 20nm. This process does not change the fixture; the integrated edge-wrapping fixture 5 is still used for localized deterministic polishing. The integrated edge-wrapping fixture 5 is fastened to the hydraulic chuck of the robotic arm polishing table to complete the final surface correction process of the part, processing it to an RMS ≤ 20nm, before proceeding to the next process. A polishing head 33 is located at the bottom of the robotic arm polishing system 32. The polishing head 33 is a rubber polishing head, and the polishing auxiliary materials are a polyurethane polishing pad and cerium oxide polishing powder. The polishing head 33 rotates at 700 r / min, its movement trajectory is a grid trajectory, the polishing pressure is 15N, and the polishing time per round is set to 1900s.

[0038] Example 3: The processing method includes the following steps: 1) Rough grinding and convex surface forming process: For flat blanks of optical materials, the aspherical process first requires milling the optimal spherical surface corresponding to the aspherical surface. The flat blank is clamped using a planar bonding milling fixture 1. The planar bonding milling fixture 1 is fastened to the hydraulic joint of the worktable of the five-axis CNC milling machine and the rough grinding of the convex spherical surface of the part is completed. The planar bonding milling fixture 1 is fastened to the base of the planar bonding milling fixture 1 by the fixture handle 28 through circumferential positioning screw holes 12. The circumferential positioning screw holes 12 are M6 screws. Multiple layers of circumferential positioning screw holes 12 are evenly distributed around the upper surface of the base of the planar bonding milling fixture 1. The hole spacing is determined by the blank size. Screw stops 27 are installed in the screw holes around the blank disc. A 0.8mm rubber buffer pad 26 is inserted between the screw stops and the blank part to prevent the part from moving during the machining process. The upper surface of the base of the planar bonding milling fixture 1 has 7 bonding ring grooves 10mm wide and 1mm deep evenly distributed. The optical blank disc is firmly bonded to the fixture base by adhesive. The adhesive remains in the bonding ring grooves 13 to increase the bonding force. The main component of the adhesive is asphalt, and the circumferential runout of the blank during the bonding process is 0.02mm. Two sets of planar bonding milling fixture lifting ring mounting holes 14-1 are symmetrically distributed on the side of the base of the planar bonding milling fixture 1. The planar bonding milling fixture lifting ring 14 is connected to the planar bonding milling fixture lifting ring mounting hole 14-1 position on the side of the base of the planar bonding milling fixture 1. The lifting rope is connected through the planar bonding milling fixture lifting ring 14. The hydraulic lifting device is used for auxiliary installation to ensure that the planar bonding milling fixture 1 is safely and reliably clamped onto the worktable of the five-axis CNC milling machine. The planar bonding milling fixture 1 and the worktable of the five-axis CNC milling machine are used to complete the rough grinding of the convex spherical surface of the flat blank. After rough grinding, a large-diameter part with a rough convex spherical radius is obtained.

[0039] 2) Rough grinding and concave surface forming process: For large-diameter parts with a rough convex spherical radius already formed, a spherical bonding milling fixture 3 is used for clamping. The spherical bonding milling fixture 3 is fastened to the hydraulic connector of the five-axis CNC milling machine table, and the rough grinding of the concave spherical surface of the part is completed. The spherical bonding milling fixture 3 is fastened by the spherical bonding milling fixture handle 30, the lifting table 29, and the base of the spherical bonding milling fixture 3 through the circumferential positioning screw holes 12. The convex surface of the optical component is firmly bonded to the arc surface of the spherical bonding milling fixture 3 substrate using an adhesive. The main component of the adhesive is asphalt. The bonding process ensures that the circumferential runout of the blank is 0.02mm. Two φ5 side vent holes 16 are symmetrically opened on the side of the spherical bonding milling fixture 3 for easy venting. Two sets of lifting holes 17 are symmetrically opened on the substrate of the spherical bonding milling fixture 3. The lifting holes 17 are M8 screw holes. The lifting table 29 is connected to the two sides of the substrate of the spherical bonding milling fixture 3 substrate by screws. Each lifting table 29 has two countersunk holes 19 for fixing to facilitate the binding of the lifting rope. The lifting rope is connected to the lifting table 29, and the hydraulic lifting device is used for auxiliary installation to ensure that the spherical bonding milling fixture 3 is safely and reliably clamped onto the worktable of the five-axis CNC milling machine. The rough grinding wheel is a bronze-bonded diamond grinding wheel with a grit size of 200#. The spherical forming is performed using the forming method. The diameter of the grinding wheel is at least half the diameter of the blank, the fillet radius is 2.5mm, the grinding wheel speed is 5000RPM, and the feed rate is 0.4mm / min. For large-diameter parts with rough convex spherical radius, the spherical bonding milling jig 3 is used to fasten the worktable of the five-axis CNC milling machine with a hydraulic connector to complete the rough grinding of the concave spherical surface of the flat blank. After rough grinding, a large-diameter spherical part with rough radius is obtained.

[0040] 3) Fine grinding of aspherical surfaces: For large-diameter spherical parts with rough radius already completed, the aspherical surface finishing process uses an integrated edge-binding fixture 5 for clamping. The fixture is hydraulically fastened to the worktable of the five-axis CNC milling machine and completes the finishing of the convex or concave aspherical surface of the part. The integrated edge-binding fixture 5 is fastened to the integrated edge-binding fixture shank 31 and the integrated edge-binding fixture 5 base by circumferential positioning screws. The sides of the large-diameter optical components are bonded to the inner side of the integrated edge clamp 5 substrate using optical glass adhesive. When the convex surface of the component is facing down, the height of the side of the integrated edge clamp 5 must exceed the arc height of the convex surface to avoid interference between the component and the integrated edge clamp 5. The lifting rope is connected to the lifting ring 20 of the integrated edge clamp, and the installation is assisted by a hydraulic lifting device. The bottom surface of the integrated edge clamp 5 has weight-reducing grooves 21 evenly distributed to ensure the rigidity of the integrated edge clamp 5 while reducing weight. The bottom vent holes 24 are evenly distributed on the bottom surface of the integrated edge clamp 5. The integrated edge clamp 5 has two transition slots 25 symmetrically distributed around its circumference to facilitate the hand support of the component for clamping on the upper plate. The lifting rope is connected to the lifting ring 20 of the integrated edge clamp, and the installation is assisted by a hydraulic lifting device. Then, the large-diameter blank is milled and shaped by a five-axis CNC milling machine. The fine grinding wheel is a resin-bonded diamond grinding wheel with a grit size of at least 800 mesh, removing at least 6 mils per cut, a wheel inclination angle of 40 degrees, a wheel diameter at least half the diameter of the blank, a fillet radius of 2.5 mm, a spiral trajectory feed method, a pitch of 0.1 mm, and a wheel linear speed of 4000 mm / min.

[0041] 4) Pre-polishing process: For large-diameter aspherical optical components that have undergone fine grinding, polishing can remove the surface damage layer and achieve a better overall surface accuracy. This process does not change the fixture; the pre-polishing still uses the integrated edge-binding fixture 5. The integrated edge-binding fixture 5 is hydraulically connected to the worktable of the five-axis CNC polishing machine and completes the convex or concave aspherical surface polishing of the part. The pre-polishing process uses an airbag-type polishing head 33, with polyurethane polishing pads and cerium oxide polishing powder as polishing aids. The polishing head 33 rotates at 400 r / min, the workpiece rotates at 350 r / min, the polishing time is 4800 s, and the air pressure of the polishing head 33 is 0.8 bar.

[0042] 5) Surface shape inspection: The surface shape of the polished large-diameter optical element 34 is inspected. If the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV, the surface shape error is judged to be small. Conversely, large-aperture optical elements 34 with large surface shape errors undergo pre-polishing again until the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV. 6) Localized shaping process: For large-aperture optical elements 34, after achieving an overall surface accuracy RMS ≤ 0.1µm and a surface finish of level IV, a robotic arm polishing system 32 is used to perform localized deterministic correction polishing on the surface of the large-aperture optical elements to achieve higher surface accuracy requirements, with an RMS ≤ 20nm. This process does not change the fixture; the integrated edge-wrapping fixture 5 is still used for localized deterministic polishing. The integrated edge-wrapping fixture 5 is fastened to the hydraulic chuck of the robotic arm polishing table to complete the final surface correction process of the part, processing it to an RMS ≤ 20nm before proceeding to the next process. A polishing head 33 is located at the bottom of the robotic arm polishing system 32. The polishing head 33 is a rubber polishing head, and the polishing auxiliary materials are a polyurethane polishing pad and cerium oxide polishing powder. The polishing head 33 rotates at 700 r / min, its movement trajectory is a grid trajectory, the polishing pressure is 15N, and the polishing time per round is set to 1800s.

[0043] The processing method includes: using a planar bonding milling fixture 1 and a spherical bonding milling fixture 3 to clamp a flat blank and perform rough grinding to form a spherical surface on a five-axis CNC milling machine; using an integrated edge-binding fixture 5 to clamp the part and perform fine grinding of the aspherical surface on a five-axis CNC milling machine; using an integrated edge-binding fixture 5 to clamp the part and perform overall polishing on a CNC polishing machine; and using an integrated edge-binding fixture 5 to clamp the part and perform local deterministic shaping on a robotic arm polishing system 32. This invention addresses issues such as clamping large-diameter optical components onto a mounting plate, component movement and detachment during processing, and ensuring high-quality positioning accuracy. It designs special tooling fixtures for different processes and describes optical processing schemes to ensure greater stability, reliability, and safety in the processing of large-diameter optical components 34.

[0044] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for fabricating a large-aperture optical element, characterized in that, The processing method includes the following steps: 1) Rough grinding convex surface forming process: The rough grinding convex surface forming process uses a flat bonding milling fixture and a five-axis CNC milling machine table to complete the rough grinding of the convex spherical surface of the flat blank. After rough grinding, a large-diameter part with a rough convex spherical radius is obtained. 2) Rough grinding concave surface forming process: For large-diameter parts with rough convex surface spherical radius, use a spherical bonding milling fixture to fasten to the hydraulic joint of the five-axis CNC milling machine table and complete the rough grinding of the concave spherical surface of the flat blank. After rough grinding, a large-diameter spherical part with rough radius is obtained. 3) Fine grinding of aspherical surfaces: For large-diameter spherical parts with rough radius opening, use an integrated edge clamping fixture to fasten the part to the hydraulic joint of the five-axis CNC milling machine table and complete the fine grinding of the convex or concave aspherical surface of the part to obtain the finely ground large-diameter aspherical optical parts. 4) Pre-polishing process: The aspherical large-diameter optical parts that have been finely ground are clamped in an integrated edge-binding fixture and polished as a whole on a CNC polishing machine. The fixture is hydraulically fastened to the CNC polishing machine table and the convex or concave aspherical surface polishing of the aspherical large-diameter optical parts is completed. 5) Surface shape inspection: Perform surface shape inspection on the polished large-diameter optical components. If the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV, the surface shape error is judged to be small. Conversely, large-aperture optical components with large surface shape errors undergo pre-polishing again until the surface shape accuracy RMS ≤ 0.1um and the surface finish reaches level IV. 6) Local deterministic reshaping process: For large-aperture optical components with surface accuracy RMS≤0.1um and surface finish reaching level IV, a robotic arm polishing system is used to perform local deterministic reshaping polishing on the surface of the large-aperture optical components until the surface accuracy RMS≤20nm, and then proceed to the next process.

2. The method for fabricating a large-aperture optical element according to claim 1, characterized in that: In steps 1) and 2), the coarse grinding wheel used in the coarse grinding operation is a bronze-bonded diamond grinding wheel with a grit size of 80# to 280#. The spherical forming process is carried out by casting. The diameter of the grinding wheel is at least half the diameter of the blank, the radius of the grinding wheel fillet is 2.5 mm, the grinding wheel speed is 3000-6000 RPM, and the feed speed is 0.1-0.5 mm / min.

3. The method for fabricating a large-aperture optical element according to claim 1, characterized in that: In step 3), the precision grinding wheel used for precision grinding is a resin-bonded diamond grinding wheel with a grit size of at least 800 mesh, a removal amount of at least 3 to 7 filaments per cut, a grinding wheel inclination angle of 20 to 45 degrees, a grinding wheel diameter at least half the diameter of the blank, a fillet radius of 2.5 mm, a spiral trajectory feeding method, a pitch of 0.05 to 0.12 mm, and a grinding wheel linear speed of not less than 3500 mm / min.

4. The method for fabricating a large-aperture optical element according to claim 1, characterized in that: In steps 4) and 5), the CNC polishing machine tool uses an airbag-type polishing head, and the polishing auxiliary materials are polyurethane polishing pads and cerium oxide polishing powder. The polishing head speed is ≥400r / min, the workpiece speed is ≥300r / min, the polishing time is at least 4800s, the polishing head air pressure is ≥0.8bar, the polishing surface accuracy reaches RMS≤0.1um, and the surface finish reaches level IV.

5. The method for fabricating a large-aperture optical element according to claim 1, characterized in that: In step 6), a polishing head is provided at the bottom of the robotic arm polishing system. The polishing head is a rubber polishing head, and the polishing auxiliary materials are polyurethane polishing pads and cerium oxide polishing powder. The polishing head rotation speed is ≥600r / min, the polishing head movement trajectory is a grid trajectory, the polishing pressure is ≤15N, and the polishing time for each round is set to at least 1800s.

6. The method for fabricating a large-aperture optical element according to claim 1, characterized in that: The planar bonding milling fixture includes: a planar bonding milling fixture handle, a planar bonding milling fixture base, a planar bonding milling fixture lifting ring, a screw stop bar, and a thick rubber buffer pad; The planar bonding milling fixture is fastened to the planar bonding milling fixture base by a planar bonding milling fixture handle and a planar bonding milling fixture base through circumferentially distributed circumferential positioning screw holes. The planar bonding milling fixture base is located at the upper end of the planar bonding milling fixture handle. A screw stop is installed on the upper end face of the planar bonding milling fixture base. The hole spacing of the circumferential positioning screw holes is determined by the blank size. The gap between the screw stop and the blank is 0.8-1.5mm. A thick rubber buffer pad is installed between the screw stop and the flat blank. The upper surface of the planar bonding milling fixture substrate is uniformly distributed with 6 to 8 bonding ring grooves, each 10 mm wide and 2 mm deep. The flat blank is firmly bonded to the planar bonding milling fixture substrate by adhesive, and the circumferential runout of the blank during the bonding process is <0.02 mm. The planar bonding milling fixture base has symmetrically arranged lifting ring mounting holes on its side corners. The lifting ring mounting holes are M10 screw holes. The upper surface of the planar bonding milling fixture base has an exhaust groove. The lifting ring of the planar bonding milling fixture is connected to the M10 screw hole on the side of the planar bonding milling fixture base, and is installed with the assistance of a hydraulic lifting device; The planar bonding milling fixture handle includes: a columnar joint, a circumferential countersunk hole, a tool relief groove, and an upper plane of the planar bonding milling fixture handle; the tool relief groove is provided on the bottom surface of the planar bonding milling fixture handle, the columnar joint is inserted into the tool relief groove, and the circumferential countersunk hole is provided through the bottom surface of the planar bonding milling fixture handle.

7. The method for fabricating a large-aperture optical element according to claim 1, characterized in that: The spherical bonding milling fixture includes: a spherical bonding milling fixture handle, a lifting table, and a spherical bonding milling fixture base; The spherical bonding milling fixture handle is fastened to the spherical bonding milling fixture base through circumferentially distributed circumferential positioning screw holes, and the spherical bonding milling fixture base is located at the upper end of the spherical bonding milling fixture handle; the top surface of the lifting platform is provided with a lifting hole, which is an M8 screw hole, and the lifting platform is symmetrically installed at both ends of the spherical bonding milling fixture base through the lifting hole. The outer side of the lifting platform is provided with a fixing countersunk hole, and a hydraulic lifting device is used for auxiliary installation; The upper surface of the spherical bonding milling fixture base is an arc surface for bonding, and the radius of the bonding arc surface is the same as that of the convex surface of the blank. The optical component is firmly bonded to the upper surface of the spherical bonding milling fixture base with adhesive. The bonding process ensures that the circumferential runout of the blank is <0.02mm. Two φ5mm side vent holes are symmetrically opened on the side of the spherical bonding milling fixture base. The spherical bonding milling fixture handle includes: a columnar joint, a circumferential countersunk hole, a tool relief groove, and a planar bonding milling fixture handle upper surface; the tool relief groove is provided on the bottom surface of the planar bonding milling fixture handle, the columnar joint is inserted into the tool relief groove, and the circumferential countersunk hole is provided through the bottom surface of the planar bonding milling fixture handle.

8. The method for fabricating a large-aperture optical element according to claim 1, characterized in that: The integrated edge-binding clamp includes: an integrated edge-binding clamp handle, an integrated edge-binding clamp lifting ring, and an integrated edge-binding clamp base. The integrated edge-binding clamp handle is fastened to the integrated edge-binding clamp base through six circumferentially distributed circumferential positioning screw holes, and the integrated edge-binding clamp base is located at the upper end of the integrated edge-binding clamp handle. The integrated edge-binding clamp base has symmetrically arranged integrated edge-binding clamp lifting ring mounting holes on its side corners, and the integrated edge-binding clamp lifting ring mounting holes are M10 screw holes. The upper surface of the inner cavity of the integrated edge-binding fixture has four weight-reducing grooves. The weight-reducing grooves are triangular and their size is adapted to the size of the integrated edge-binding fixture. The integrated edge-binding fixture base has four φ5mm bottom vent holes evenly distributed around its bottom circumference; the diameter of the bonding surface of the integrated edge-binding fixture base is 0.1mm smaller than the outer diameter of the optical component; the bottom surface of the optical component is placed at the step of the bonding surface of the integrated edge-binding fixture base; the side of the optical component is firmly bonded to the bonding surface of the integrated edge-binding fixture base; the bonding process ensures that the circumferential runout of the blank is less than 0.1mm. The integrated edge-binding clamp base has two arc-shaped transition slots symmetrically opened on its circumference for clamping the hand clamp with the part. When clamping with the concave surface, it ensures that the arc height of the convex surface of the part does not interfere with the integrated edge-binding clamp base. The lifting ring of the integrated edge-binding clamp is connected to the screw hole on the side of the integrated edge-binding clamp base, and the installation is assisted by a hydraulic lifting device. The integrated edge-binding fixture handle includes: a columnar connector, a circumferential countersunk hole, a tool relief groove, and a flat surface of the planar bonding milling fixture handle; the tool relief groove is provided on the bottom surface of the planar bonding milling fixture handle, the columnar connector is inserted into the tool relief groove, and the circumferential countersunk hole is provided through the bottom surface of the planar bonding milling fixture handle.

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