An optical process and lapping and polishing machine for processing optical mirrors with a regular hexagonal shape
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZIJINSHAN ASTRONOMICAL OBSERVATORY CHINESE ACAD OF SCI
- Filing Date
- 2024-01-19
- Publication Date
- 2026-05-29
Smart Images
Figure CN117840865B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optical processing technology, specifically to an optical process and grinding and polishing machine for processing regular hexagonal optical mirrors. Background Technology
[0002] In recent years, with the continuous improvement of adaptive optics and active optics technologies, large modular mirror astronomical telescopes are moving from the 10-meter class to the 30-40-meter class, such as the 30-meter TMT in the United States and the 39-meter ELT in Europe, which has promoted the upgrading of the manufacturing process of regular hexagonal aspherical mirrors with a diagonal diameter of about 1.4 meters. Large modular mirror telescopes include optical designs that use regular hexagonal spherical mirrors to form the primary mirror, combined with aspherical secondary mirrors to form the optical system. There are also reflecting Schmidt telescopes that use regular hexagonal spherical mirrors to form the primary mirror, combined with deformable reflecting correctors made of regular hexagonal plane mirrors. For example, my country's Guo Shoujing Telescope (LAMOST) uses 37 regular hexagonal spherical mirrors with a diagonal diameter of 1.1 meters and a thickness of 75 millimeters (diameter-to-thickness ratio of 14.7:1) and a radius of curvature of 40 meters to form the primary mirror with an exit diameter of 6.5 meters × 6.0 meters. It uses 24 regular hexagonal plane mirrors with a diagonal diameter of 1.1 meters and a thickness of 25 millimeters (diagonal diameter-to-thickness ratio of 44:1) to form a plane mirror with an exit diameter of 5.7 meters × 4.4 meters. An active optics mechanism drives the plane mirrors to deform into reflecting Schmidt correctors, which, together with the spherical primary mirror, form a reflecting Schmidt telescope. The practical application of these regular hexagonal plane mirrors and spherical mirrors has promoted the development of optical processes for fabricating regular hexagonal optical mirrors.
[0003] As is well known, in the optical processes of processing plane mirrors and spherical mirrors on grinding and polishing machines commonly used in optical workshops, circular mirrors, due to the central symmetry of their edges with respect to the center point, can be easily processed using precision grinding and polishing discs of the same diameter and also circular in shape, resulting in a high-precision optical surface. However, for hexagonal optical mirrors, the symmetry of their edges with respect to the center point varies. If hexagonal precision grinding and polishing discs are used directly for optical processing, it usually results in optical surfaces with collapsed edges and warped corners, failing to achieve the precision required for optical applications. Traditional processing techniques for hexagonal optical mirrors typically include the "edge-cutting method" and the "edge-jointing method." The "edge-cutting method" involves cutting off six edges along the six directions of the circumference of a circular mirror that has already been precision-machined to meet the required accuracy, thus obtaining a hexagonal optical mirror. However, this method may cause deformation of the mirror blank due to the release of stress within the blank material, leading to a decrease in the precision of the optical surface. The "edge splicing method" is an improved version of the "edge cutting method." It involves first cutting a circular mirror blank into a regular hexagonal mirror blank, then using adhesive to glue the six cut edge materials back to the six edges of the regular hexagonal mirror blank. After the regular hexagonal mirror blank is spliced back into the circular mirror blank, optical processing is performed using a circular precision grinding disc and polishing disc of the same diameter. Once the optical surface meets the required precision, the splicing material is removed to obtain the finished regular hexagonal mirror surface, thus avoiding the stress deformation problem of the "edge cutting method."
[0004] The "ring polishing method" for processing hexagonal optical mirrors evolved from the "edge splicing method" and is particularly suitable for processing large-sized ultra-thin (diameter-to-thickness ratio exceeding 20:1) hexagonal plane mirrors. It involves placing a glass ring with a circular outer surface and a hexagonal inner surface around the ultra-thin hexagonal plane mirror, which has already undergone precise dimensional machining and surface grinding. A few millimeters of gap is left between the outer ring and the mirror surface to allow for relative movement rather than sticking. Both are then placed on a polishing asphalt layer on a large ring polishing machine's annular turntable. Polishing fluid is continuously sprayed onto the surface of the polishing asphalt layer on the annular turntable through a circulation system. The annular turntable rotates at a certain speed, causing the outer ring and the mirror surface to rotate and polish on the polishing asphalt layer. Simultaneously, a large and heavy circular plane mirror is also rotating and polishing on the annular turntable, pressing down the polishing asphalt layer to maintain its flatness. Typically, the diameter of the ring turntable of a large ring polishing machine is more than three times the diameter of the plane mirror that can be processed. For example, the ring polishing machine used to process the 1.1-meter diagonal diameter regular hexagonal ultrathin plane mirror of the Guo Shoujing Telescope mentioned above has a turntable diameter of 3.6 meters and can polish three 1.1-meter diagonal diameter regular hexagonal ultrathin plane mirrors at the same time. The workshop environment generally requires constant temperature conditions.
[0005] Overall, both the "edge cutting method" and the "edge splicing method" have relatively complicated processes. The "ring polishing machine method" has high production efficiency, but the current processing technology relies on large ring polishing machines, and the equipment cost and workshop environment requirements are relatively high. In addition, it can only process regular hexagonal plane mirrors and not regular hexagonal spherical mirrors. Summary of the Invention
[0006] The main technical objective of this invention is to overcome the shortcomings and limitations of existing optical processes and to propose a process for processing regular hexagonal optical mirrors on grinding and polishing machines commonly used in optical workshops.
[0007] The technical solution provided by this invention includes:
[0008] An optical process for processing regular hexagonal optical mirrors, wherein a grinding and polishing machine is used to grind and polish the regular hexagonal optical mirrors, characterized in that the contour lines of the grinding disc and the polishing disc of the grinding and polishing machine are irregular hexagonal contour lines;
[0009] The method for defining the contour line of the irregular hexagon is as follows:
[0010] Based on the regular hexagonal outline of the hexagonal optical mirror to be processed, the six corner points are adjusted by the same set distance away from the center, and the midpoints of the six sides are adjusted by the same set distance towards the center. Based on the adjusted adjacent corner points and the midpoints of the sides before the adjacent corner points, an arc line is determined. The arc line is used as the side of the irregular hexagon to obtain the irregular hexagonal outline.
[0011] Furthermore, the distance between opposite corner points is defined as the diagonal diameter, and the distance between the midpoints of opposite sides is defined as the side diameter. The diagonal diameter of the irregular hexagon is 103% to 107% of the diagonal diameter of the regular hexagonal optical mirror to be processed, and the side diameter of the irregular hexagon is 95% to 98% of the side diameter of the regular hexagonal optical mirror to be processed.
[0012] Furthermore, a fine grinding patch array is set on the body of the fine grinding disc to form the processing surface of the fine grinding disc. The fine grinding patch array is composed of detachable or repairable fine grinding patches, with patch grooves left between rows and columns. A polishing patch array is set on the body of the polishing disc to form the processing surface of the polishing disc. The polishing patch array is composed of detachable or repairable polishing patches, with patch grooves left between rows and columns.
[0013] Preferably, the finely ground patch is an aluminum patch, and the polished patch is an asphalt patch.
[0014] Furthermore, the optical process of this invention includes a step for inspecting the surface shape of the regular hexagonal optical mirror during the grinding or polishing process; when the inspection result is a collapsed or warped edge, the working area of the patch located at the edge of the grinding or polishing disc is adjusted by replacement or correction, and the inspection and adjustment steps are repeated until the error converges to the set requirements.
[0015] Furthermore, when grinding a regular hexagonal optical mirror using a fine grinding disc, the stroke of the fine grinding disc is set to 1 / 3 to 1 / 4 of the diagonal diameter of the fine grinding disc; when polishing a regular hexagonal optical mirror using a polishing disc, the stroke of the polishing disc is set to 1 / 3 to 1 / 4 of the diagonal diameter of the polishing disc.
[0016] A grinding and polishing machine for processing regular hexagonal optical mirrors, comprising a fine grinding disc and a polishing disc, characterized in that the fine grinding disc and the polishing disc have irregular hexagonal outlines;
[0017] The irregular hexagonal outline has six corner points evenly distributed along the circumference, and adjacent corner points are connected by arc-shaped edges, with the midpoint of the arc-shaped edges located at the middle of the adjacent corner points.
[0018] Define the distance between opposite corner points as the diagonal diameter and the distance between the midpoints of opposite sides as the side diameter. Then, the diagonal diameter of the irregular hexagon is greater than the diagonal diameter of the regular hexagonal optical mirror to be processed, and the side diameter of the irregular hexagon is smaller than the side diameter of the regular hexagonal optical mirror to be processed.
[0019] Furthermore, the diagonal diameter of the irregular hexagon is 103% to 107% of the diagonal diameter of the regular hexagonal optical mirror, and the side diameter of the irregular hexagon is 95% to 98% of the side diameter of the regular hexagonal optical mirror.
[0020] Furthermore, the fine grinding disc consists of a fine grinding disc body and multiple detachable or adjustable fine grinding patches, which are arranged in an array, covering the surface of the fine grinding disc body, and leaving inter-pattern grooves between rows and columns; the polishing disc consists of a polishing disc body and multiple detachable or adjustable polishing patches, which are arranged in an array, covering the surface of the polishing disc body, and leaving inter-pattern grooves between rows and columns.
[0021] Preferably, the finely ground patch is an aluminum patch, and the polished patch is an asphalt patch. Beneficial effects
[0022] 1) The optical process and grinding and polishing machine of the present invention can directly grind and polish regular hexagonal optical mirrors by improving the fine grinding disc and polishing disc. Compared with the existing processes such as "edge cutting method" and "edge splicing method" for processing regular hexagonal optical mirrors, the process flow is simplified and the work efficiency is significantly improved.
[0023] 2) The optical process of this invention can be implemented on the grinding and polishing machines commonly used in optical workshops. Only the fine grinding disc and polishing disc need to be replaced, without the need for other cumbersome equipment or tools. The improvement cost is low and it is suitable for widespread use. Attached Figure Description
[0024] Figure 1 A comparative schematic diagram showing the outline of the precision grinding / polishing disc and the regular hexagonal optical mirror;
[0025] Figure 2 This is a schematic diagram of the machining surface structure of a fine grinding / polishing disc;
[0026] Figure 3 A schematic diagram illustrating a method for making minor adjustments to the working area of the corners and edges of the grinding and polishing discs;
[0027] Figure 4 This diagram illustrates the working state of a precision grinding / polishing disc during the processing of a regular hexagonal spherical mirror.
[0028] Figure 5 This is a schematic diagram of the working state of a fine grinding / polishing disc when processing a regular hexagonal plane mirror.
[0029] Figures 1 to 5 The corresponding symbols in the text refer to the following objects or parameters:
[0030] a. Regular hexagonal optical mirror; b. Precision grinding disc or polishing disc;
[0031] a1. The corner of a regular hexagonal optical mirror; a2. The edge of a regular hexagonal optical mirror;
[0032] b1. Corner of the grinding or polishing disc; b2. Edge of the grinding or polishing disc; b3. Patch at the edge of the grinding or polishing disc; b4. Groove between patches on the grinding or polishing disc; b5. Grinding or polishing patches of different sizes after replacement; b6. Grinding or polishing patches after surface trimming or scraping; L. Stroke length of the grinding or polishing disc during operation. Detailed Implementation
[0033] This invention discloses an optical process for processing regular hexagonal optical mirrors, including the fabrication process of a fine grinding disc and a polishing disc, and the fine grinding and polishing processes for processing the regular hexagonal optical mirrors using the aforementioned fine grinding discs and polishing discs. The regular hexagonal optical mirror can be a spherical mirror or a planar mirror. To clarify the technical concept of this invention, the implementation process and principle of this invention will be described in detail below with reference to the accompanying drawings.
[0034] (1) Preparation process of fine grinding disc and polishing disc
[0035] Since the "edge cutting method" and "edge splicing method" are too cumbersome, in order to simplify the process, this invention still considers the processing method of directly grinding and polishing the regular hexagonal optical mirror surface. However, since circular fine grinding discs and polishing discs (hereinafter referred to as tools in some places) are not suitable for processing regular hexagonal optical mirror surfaces, this invention considers using hexagonal tools. Based on the working principle of commonly used grinding and polishing machines, if a regular hexagonal tool with the same shape and size as the optical mirror to be processed is used, the corners and edges of the tool will continuously meet the corners and edges of the regular hexagonal optical mirror. The amount of grinding by the tool corners on the mirror corners and by the tool edges on the mirror edges is uniform. However, we have found that because the size of the tool corners exceeds the size of the mirror edges, the grinding by the tool corners on the mirror edges is excessive, and the mirror edges will gradually become lower, resulting in edge collapse. Similarly, if the size of the tool edges is shorter than the size of the mirror corners, the amount of grinding by the tool edges on the mirror corners is insufficient, and therefore the mirror corners will gradually become higher, resulting in edge warping.
[0036] To eliminate curling at the corners and sagging at the edges of the mirror, we improved the grinding and polishing tools.
[0037] The precision grinding disc and polishing disc designed in this invention have an irregular hexagonal outline with a shape and size similar to the regular hexagonal optical mirror surface to be processed. The specific preparation method is as follows:
[0038] Based on the hexagonal outline of the hexagonal optical mirror to be processed, the six corner points are adjusted by the same set distance Δx away from the center, and the midpoints of the six sides are adjusted by the same set distance Δy towards the center. An arc is determined based on the adjusted adjacent corner points and the midpoints of the sides before the adjacent corner points. After the arc is used as the side of the irregular hexagon, the outline of the irregular hexagon is obtained. Then, the shape of the fine grinding disk or polishing disk is prepared according to the outline.
[0039] like Figure 1 As shown, the diagonal diameter of the prepared grinding and polishing discs should be larger than the diagonal diameter of the hexagonal optical mirror to be processed, while the opposite side diameter should be smaller than the opposite side diameter of the hexagonal optical mirror to be processed. The diagonal diameter refers to the distance between opposite corner points of the regular hexagon / irregular hexagon, and the opposite side diameter refers to the distance between the midpoints of opposite sides of the regular hexagon / irregular hexagon. The former can also be understood as the diameter of the circumcircle of the regular hexagon / irregular hexagon, and the latter as the diameter of the incircle of the regular hexagon / irregular hexagon.
[0040] Compared to processing with a regular hexagonal tool of the same shape and size as the optical mirror to be processed, this invention increases the amount of grinding on the mirror corners by increasing the size of the tool's corners, while decreasing the size of its edges to reduce the amount of grinding on the mirror edges by the tool's edges. Although increasing the size of the tool's corners will further increase the amount of grinding on the mirror edges by the tool's corners, this can be balanced by decreasing the size of the tool's edges, effectively preventing edge collapse. Similarly, decreasing the size of the tool's edges will exacerbate the insufficient amount of grinding on the mirror corners by the tool's edges, but this effect can be balanced by increasing the size of the tool's corners, effectively preventing edge warping.
[0041] The specific values of Δx and Δy can be determined experimentally. During actual processing, the values of Δx and Δy may vary depending on factors such as the specific processing materials, equipment, and workshop environment. Generally, the diagonal diameter of the irregular hexagon ranges from 103% to 107% of the diagonal diameter of the regular hexagonal optical mirror to be processed, and the side diameter of the irregular hexagon ranges from 95% to 98% of the side diameter of the regular hexagonal optical mirror to be processed.
[0042] For tools with fixed Δx and Δy values, if the machined mirror surface still has some edge collapse or warping issues (caused by some unpredictable or unavoidable errors), a small adjustment can be made by modifying the working area of the tool.
[0043] To facilitate fine-tuning of the prepared grinding and polishing discs, in this embodiment, the grinding disc is designed to consist of a disc body and multiple detachable or adjustable grinding patches. These patches are arranged in an array and attached to the surface of the disc body, with grooves b4 between rows and columns to facilitate the flow of the grinding fluid. Similarly, the polishing disc is designed to consist of a disc body and multiple detachable or adjustable polishing patches. These patches are arranged in an array and attached to the surface of the disc body, with grooves b4 between rows and columns to facilitate the flow of the polishing fluid. Replacing a smaller patch with a larger one increases the working area and thus the amount of grinding required at the corresponding position on the mirror surface, eliminating errors such as raised edges. Conversely, replacing a larger patch with a smaller one or adjusting it to a smaller size reduces the working area and thus the amount of grinding required at the corresponding position on the mirror surface, eliminating errors such as collapsed edges.
[0044] like Figure 2 , Figure 3As mentioned above, a complete fine-grinding patch or polishing patch is a square piece, while the fine-grinding patch or polishing patch near the tool edge needs to be cut according to the shape of the tool outline. The width of the patch groove b4 generally follows a 10:1 ratio, that is, if the patch size is 50mm×50mm, the patch groove is 5mm, and if the patch size is 100mm×100mm, the patch groove is 10mm. However, this ratio is not a strict rule that must be followed. In actual operation, the size setting of the patch and the patch groove should prioritize ease of operation.
[0045] In this embodiment, the fine grinding patch is made of aluminum, and the polishing patch is made of tar. The aluminum patch, being a metal material, is easy to disassemble and replace. The tar patch, however, has polishing tar on it, making it relatively inconvenient to disassemble. While still usable, its working area can be adjusted by trimming the tar layer. Besides aluminum, the fine grinding patch can also be made of other metal materials or other materials with abrasive properties. Similarly, the polishing patch can be made of other materials with polishing properties. Regarding the tar patch, the polishing tar on its surface is a mixture of tar and rosin. A higher tar content results in a softer patch, while a higher rosin content results in a harder patch. In practice, aside from the personal habits of optical technicians, generally speaking, if the mirror material has high hardness, the workshop environment temperature is high, or the requirements for the mirror surface curvature are strict, the hardness of the polishing tar will be higher; conversely, it will be lower.
[0046] (2) Fine grinding and polishing processes of regular hexagonal spherical mirrors
[0047] like Figure 4 In one example, the hexagonal optical mirror 'a' is a regular hexagonal spherical mirror with a flat bottom surface and a concave spherical top surface, which is the hexagonal optical mirror surface to be processed. The surfaces of the grinding disc and the polishing disc are convex spherical surfaces, matching the surface to be processed of the hexagonal optical mirror 'a'.
[0048] Fine grinding process: The hexagonal spherical mirror blank, whose dimensions have been precisely machined, is placed on the support mechanism of the grinding and polishing machine turntable. After adjusting the level and concentricity, the mirror blank is finely ground using the fine grinding disc prepared in the above process. The grinding disc unloading mechanism of the grinding and polishing machine is used to reduce the pressure of the fine grinding disc on the mirror blank. Starting with 180# (mesh) grinding fluid, the fine grinding disc is used to finely grind the stroke L of 1 / 3 to 1 / 4 of the angular diameter. Combined with the measurement results of the overall surface, corners and edges of the hexagonal spherical mirror by the profilometer, timely adjustments are made to the surface. Replace or trim the aluminum patches at the corners or edges of the grinding disc to slightly adjust the working area of the corners or edges. This, combined with the flexible variation of the grinding disc's stroke L, eliminates the warping at the corners and the collapse at the edges of the hexagonal spherical mirror. During the grinding process, control the radius of curvature and thickness of the hexagonal spherical mirror within the tolerance range. Gradually change the grinding fluid up to 303#. When the surface undulation measured by the profilometer is 1-2 micrometers and the surface roughness is uniform without large and deep scratches or pits, the grinding process is completed.
[0049] Polishing Process: The hexagonal spherical mirror and polishing machine turntable, having undergone fine grinding, are thoroughly cleaned. The polishing disc prepared using the above process is used to polish the hexagonal spherical mirror. The disc unloading mechanism of the polishing machine is used to reduce the pressure of the polishing disc on the hexagonal spherical mirror. The polishing disc is used to polish the travel distance L from 1 / 3 to 1 / 4 of the angular diameter. Qualitative and quantitative tests are performed on the hexagonal spherical mirror using a knife-edge gauge and a spherical Fizeau interferometer. Based on the test results, the polishing disc angle is adjusted. The tar patches on the parts and edges are scraped and trimmed. The working area of the polishing disc at the corners and edges is adjusted in a timely and minute manner. With the flexible change of the polishing disc's stroke L, the warping at the corners and the collapse at the edges of the regular hexagonal spherical mirror are controlled and eliminated. The error of the polished surface is gradually reduced to within the accuracy tolerance range. The radius of curvature of the polished surface is controlled within the tolerance range until the regular hexagonal spherical mirror is completely polished and the surface finish meets the requirements. Finally, a digital laser interferometer is used to give a quantitative inspection report of the regular hexagonal spherical mirror.
[0050] (3) Fine grinding and polishing processes for regular hexagonal plane mirrors
[0051] like Figure 5 In one example shown, the regular hexagonal optical mirror a is a regular hexagonal plane mirror with a flat bottom surface, which is the regular hexagonal optical mirror surface to be processed. The processing surfaces of the grinding disc and the polishing disc are also flat.
[0052] Fine grinding process: The hexagonal plane mirror blank, whose outer dimensions have been precisely machined, is placed on the turntable of the grinding and polishing machine using the Kuderberg oil point support method. After adjusting the level and concentricity, the mirror blank is finely ground using a fine grinding disc made in the above process. The grinding disc unloading mechanism of the grinding and polishing machine is used to reduce the pressure of the fine grinding disc on the hexagonal plane mirror blank. Starting with 180# grinding fluid, the fine grinding disc is used to finely grind the stroke L of 1 / 3 to 1 / 4 of the corner diameter. Combined with a profilometer, the overall surface, corners and edges of the hexagonal plane mirror are finely ground. Based on the measurement results, the aluminum patches at the corners and edges of the grinding disc are replaced or appropriately trimmed to slightly adjust the working area of the corners and edges of the grinding disc. This, combined with the flexible variation of the grinding disc's stroke L, eliminates the warping at the corners and the collapse at the edges of the regular hexagonal plane mirror. At the same time, the thickness of the regular hexagonal plane mirror is controlled within the tolerance range. The grinding fluid is gradually changed up to 303#. When the surface undulation measured by the profilometer is within 1-2 micrometers, and the surface roughness is uniform without large and deep scratches and pits, the fine grinding process is completed.
[0053] Polishing Process: The hexagonal plane mirror and the polishing machine turntable, having undergone fine grinding, are thoroughly cleaned. The polishing disc is used to polish the hexagonal plane, and the disc unloading mechanism of the polishing machine is used to reduce the pressure of the polishing disc on the hexagonal plane mirror. The polishing disc is used to polish the travel length L of 1 / 3 to 1 / 4 of the angle diameter. Based on the inspection results of the polished surface using a plane template, a plane Fiso interferometer, and the Cammon scheme + knife-edge gauge, the surface of the tar patch at the corners and edges of the polishing disc is appropriately scraped. The working area at the corners and edges of the polishing disc is slightly adjusted to eliminate edge warping and edge collapse at the corners and edges of the hexagonal plane mirror, gradually reducing the error of the polished surface until the flatness of the hexagonal plane mirror meets the accuracy requirements, the mirror surface is completely polished, and the surface finish meets the requirements. A final inspection using the Cammon scheme + digital laser interferometer provides a quantitative inspection report for the hexagonal plane mirror.
[0054] The optical process of this invention is particularly suitable for processing large-sized regular hexagonal optical mirrors, such as those used in modular mirror astronomical telescopes. Below are the process parameters for two specific embodiments applied to modular mirror astronomical telescopes:
[0055] 1) The hexagonal spherical mirror with a diagonal diameter of 1.1 meters, a radius of curvature of 40 meters, and a thickness of 75 mm is used for machining the main mirror of the Guo Shoujing Telescope. The grinding disc and polishing disc are both 100 mm thick and are thin-walled cast aluminum parts with radial and circumferential reinforcing ribs on the back.
[0056] The precision grinding disc has a Δx of 40mm and a Δy of 20mm. The precision grinding pads are 50mm×50mm×3mm (length×width×thickness, the same below) aluminum sheets. The width of the groove between the pads is 5mm. The precision grinding stroke L can be flexibly varied between 360mm and 270mm.
[0057] The polishing pad has a Δx of 30mm and a Δy of 15mm. The polishing pads are made of 80mm×80mm×6mm polishing asphalt with a groove width of 6mm between the pads. The polishing stroke L can be flexibly adjusted between 350mm and 260mm.
[0058] 2) The above-mentioned Guo Shoujing telescope splicing reflection Schmidt correction plate uses a regular hexagonal ultrathin plane mirror with a diagonal diameter of 1.1 meters and a thickness of 25 mm. The fine grinding disk and polishing disk are both 100 mm thick and thin-walled cast aluminum parts with radial and circumferential reinforcing ribs on the back.
[0059] The precision grinding disc has a Δx of 30mm and a Δy of 15mm. The precision grinding patch b3 is a 50mm×50mm×3mm aluminum sheet with a groove width of 5mm between patches. The precision grinding stroke L can be flexibly adjusted between 360mm and 270mm.
[0060] The polishing pad has a Δx of 20mm and a Δy of 10mm. The polishing patch b3 is made of 80mm×80mm×6mm polishing asphalt. The groove width between the patches is 6mm. The polishing stroke L can be flexibly adjusted between 350mm and 250mm.
[0061] The working principle and optical processing of a conventional grinding and polishing machine are briefly described below:
[0062] The main body of the machine is a sturdy chassis with a circular turntable at its center. The turntable contains a main shaft, worm gear, motor, and other drive mechanisms. The turntable is equipped with a support, fixing, and adjustment mechanism for the mirror surface. A swing arm mechanism is located beside the chassis. Both the turntable and the swing arm mechanism are driven by a motor to rotate or swing. When processing the mirror, the mirror blank is placed on the turntable and securely supported by the support mechanism. It is fixed and adjusted to be level and concentric with the turntable's rotation axis. The tool (fine grinding disc or polishing disc) is supported by a bearing mechanism located at the center of its back. The weight of the tool, suspended at the head of the swing arm of the grinding and polishing machine, can be borne by the unloading mechanism on the swing arm, and the unloading amount can be adjusted to reduce the pressure on the mirror blank and adjust the friction coefficient during grinding and polishing. During optical processing, a certain amount of grinding or polishing fluid is first added between the tool and the mirror blank. Then, the turntable is started to drive the mirror blank to rotate slowly, and then the swing arm is started to swing slowly to push the tool to move back and forth on the mirror blank according to a certain stroke. At the same time, the tool rotates with the rotation of the mirror blank. In this way, the grinding or polishing of the mirror blank begins.
[0063] The working principle of the grinding and polishing machine is a well-known technology and will not be elaborated here.
[0064] The advantages of this invention are that it uses a fine grinding disc and a polishing disc with an shape similar to a regular hexagonal mirror surface to directly fine grind and polish regular hexagonal spherical mirror blanks and plane mirror blanks. This can be carried out on grinding and polishing machines commonly used in optical workshops. By flexibly adjusting the shape and working area of the corners and edges of the fine grinding disc and the polishing disc, high-precision regular hexagonal spherical mirrors and plane mirrors can be obtained. This overcomes the shortcomings and limitations of existing optical processes such as edge cutting, edge splicing, and ring polishing in processing regular hexagonal spherical mirrors and plane mirrors, simplifies the process flow, improves production efficiency, and does not increase the equipment cost of the optical workshop.
[0065] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments; the embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope. The scope of protection of this invention is defined by the appended claims, specification, and their equivalents.
Claims
1. An optical process for processing regular hexagonal optical mirrors, characterized in that: The outlines of the grinding disc and polishing disc of the grinding and polishing machine are irregular hexagonal outlines; The method for defining the contour line of the irregular hexagon is as follows: Based on the regular hexagonal outline of the hexagonal optical mirror to be processed, the six corner points are adjusted by the same set distance away from the center, and the midpoints of the six sides are adjusted by the same set distance towards the center. Based on the adjusted adjacent corner points and the midpoints of the sides before the adjacent corner points, an arc line is determined. The arc line is used as the side of the irregular hexagon to obtain the irregular hexagonal outline.
2. The optical process for processing a regular hexagonal optical mirror according to claim 1, characterized in that: The distance between opposite corner points is defined as the diagonal diameter, and the distance between the midpoints of opposite sides is defined as the side diameter. The diagonal diameter of the irregular hexagon is 103% to 107% of the diagonal diameter of the regular hexagonal optical mirror to be processed, and the side diameter of the irregular hexagon is 95% to 98% of the side diameter of the regular hexagonal optical mirror to be processed.
3. The optical process for processing a regular hexagonal optical mirror according to claim 1 or 2, characterized in that: A fine grinding patch array is set on the disc body of the fine grinding disc to form the processing surface of the fine grinding disc. The fine grinding patch array is composed of detachable or trimmable fine grinding patches, and grooves are left between the patches in the rows and columns. A polishing patch array is set on the body of the polishing pad to form the processing surface of the polishing pad. The polishing patch array is composed of detachable or trimmable polishing patches, and grooves are left between the patches in the rows and columns.
4. The optical process for processing a regular hexagonal optical mirror according to claim 3, characterized in that: The precision-ground patch is an aluminum patch, and the polishing patch is an asphalt patch.
5. The optical process for processing a regular hexagonal optical mirror according to claim 3, characterized in that, The process of grinding or polishing a regular hexagonal optical mirror includes a step to inspect the surface shape of the regular hexagonal optical mirror; When the inspection result is a collapsed or warped edge, the working area of the patch located at the edge of the grinding or polishing disc is adjusted by replacement or correction. The inspection and adjustment steps are repeated until the error converges to the set requirements.
6. The optical process for processing a regular hexagonal optical mirror according to claim 1, characterized in that: When using a fine grinding disc to grind a regular hexagonal optical mirror, the stroke of the fine grinding disc is set to 1 / 3 to 1 / 4 of the diagonal diameter of the fine grinding disc; When polishing a regular hexagonal optical mirror using a polishing pad, the stroke of the polishing pad is set to 1 / 3 to 1 / 4 of the diagonal diameter of the polishing pad.
7. A grinding and polishing machine for processing regular hexagonal optical mirrors, comprising a fine grinding disc and a polishing disc, characterized in that, The grinding disc and polishing disc have irregular hexagonal outlines; The irregular hexagonal outline has six corner points evenly distributed along the circumference, and adjacent corner points are connected by arc-shaped edges, with the midpoint of the arc-shaped edges located at the middle of the adjacent corner points. Define the distance between opposite corner points as the diagonal diameter and the distance between the midpoints of opposite sides as the side diameter. Then, the diagonal diameter of the irregular hexagon is greater than the diagonal diameter of the regular hexagonal optical mirror to be processed, and the side diameter of the irregular hexagon is smaller than the side diameter of the regular hexagonal optical mirror to be processed.
8. The grinding and polishing machine for processing regular hexagonal optical mirrors as described in claim 7, characterized in that: The diagonal diameter of the irregular hexagon is 103% to 107% of the diagonal diameter of the regular hexagonal optical mirror, and the side diameter of the irregular hexagon is 95% to 98% of the side diameter of the regular hexagonal optical mirror.
9. A grinding and polishing machine for processing regular hexagonal optical mirrors as described in claim 7, characterized in that: The fine grinding disc consists of a fine grinding disc body and multiple detachable or adjustable fine grinding patches. The fine grinding patches are arranged in an array, covering the surface of the fine grinding disc body, and grooves are left between the patches in the rows and columns. The polishing disc consists of a polishing disc body and multiple removable or adjustable polishing pads. The polishing pads are arranged in an array, covering the surface of the polishing disc body, and grooves are left between the rows and columns.
10. A grinding and polishing machine for processing regular hexagonal optical mirrors as described in claim 9, characterized in that: The precision-ground patch is an aluminum patch, and the polishing patch is an asphalt patch.