A processing device and method for milling and grinding a meniscus aspherical lens
By using a tooling fixture consisting of a base and auxiliary blocks, reinforced with 502 glue and with a unified positioning benchmark, the problem of insufficient positioning accuracy and firmness in milling meniscus aspherical lenses is solved, achieving high-precision control of lens center deviation and improving the versatility of tooling fixtures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIAN NORTH ELECTRO OPTIC TECH DEFENSE
- Filing Date
- 2024-06-24
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies struggle to simultaneously ensure high-precision positioning and robustness in the milling process of meniscus aspherical lenses, and the lack of versatility in tooling fixtures makes it difficult to achieve the required precision of less than 1′ for lens center deviation.
The tooling fixture, consisting of a base and an auxiliary block, is reinforced with 502 glue through the threaded connection between the base positioning shaft and the auxiliary block. This ensures the positioning accuracy and stability of the meniscus aspherical lens during the milling process. Furthermore, it eliminates repetitive positioning errors by using a unified positioning datum and marking lines. The tooling fixture is designed to accommodate lenses with different spherical radii.
It improves the lens center deviation accuracy of milled meniscus aspherical lenses, ensures positioning accuracy and stability, enhances the versatility of tooling fixtures, and can effectively control the lens center deviation within 1′.
Smart Images
Figure CN118720927B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of meniscus aspherical lens processing technology, specifically relating to a processing apparatus and method for milling meniscus aspherical lenses. Background Technology
[0002] The characteristics of a meniscus aspherical lens are that its concave surface is spherical with a small radius of curvature. During manufacturing, because the diameter of this spherical surface is smaller than the rough-ground outer diameter of the part, an end face is usually required. The convex surface is aspherical; hence, it is referred to as a meniscus aspherical lens. In the manufacturing process, compared to biconvex or biconcave lenses, the center deviation of this type of lens is more difficult to control. However, in practical applications, to ensure higher imaging quality in the optical system, the design drawings require the center deviation of the part to be within 1′, which is difficult to achieve for this type of aspherical lens. In the manufacturing process of aspherical lenses, the spherical surface is generally machined first, followed by the aspherical surface. When the part is transferred to the milling process for the aspherical surface, the spherical surface has already been polished and coated with a protective camouflage. Since the aspherical part has only one axis of symmetry, once machining is complete, it is difficult to correct the center deviation through the edge grinding process later. Therefore, the relative deviation between this surface and the optical axis of the completed spherical surface can only be controlled and guaranteed during the milling process. This makes the requirements for tooling fixtures and processing equipment higher and the processing difficulty greater when milling these parts.
[0003] In existing technologies, CNC milling machines are commonly used when milling the aspherical surface of meniscus-shaped aspherical parts. Special tooling fixtures are designed according to the shape requirements of the meniscus-shaped aspherical lens to be machined. The meniscus-shaped aspherical lens to be machined consists of the spherical end plane 3-1, the outer cylindrical surface 3-2, the aspherical surface 3-3, and the spherical surface 3-4 of the part. Figure 4There are generally two positioning methods for processing meniscus aspherical lenses. The first method uses a concave spherical surface for positioning, employing a lever dial indicator to measure the runout of the part's outer diameter, controlling it to within 0.01mm. Due to factors such as tooling fixture errors and uneven thickness of the protective paint on the concave spherical surface, it is not possible to simultaneously guarantee that both the outer diameter runout and the end face runout are within 0.01mm. When processing biconvex aspherical parts using this positioning method, since the lens center deviation requirement is generally between 2′ and 3.5′, the center deviation of the finished part can meet the drawing requirements. However, for milling meniscus aspherical lenses, the maximum center deviation requirement is within 1′, and the center deviation of the finished part often exceeds the tolerance. Because this positioning method has a large contact area between the positioning surface and the tooling fixture, the spherical surface is supported in both the horizontal and vertical directions, making it less prone to detachment during milling. The second method uses end face positioning; after the tooling fixture is processed by an external cylindrical grinder, its end face runout can reach within 0.002mm. Because it uses end-plane positioning, the meniscus aspherical lens does not produce surface tilt angle error during clamping; only the eccentricity difference caused by the runout of the part's outer diameter needs to be controlled. If a lever dial indicator is used to measure the runout of the part's outer diameter, both the outer diameter runout and the end-plane runout can be ensured to be within 0.005mm. This positioning method offers high accuracy, but because the spherical end-plane of the meniscus aspherical lens varies in size, the contact area between the positioning surface and the tooling fixture is small, resulting in a lack of horizontal support and a tendency to detach during milling.
[0004] The shape of meniscus aspherical lenses necessitates two positioning methods during milling: spherical positioning and end-plane positioning. Each method has its advantages and disadvantages. Spherical positioning is more secure but has lower positioning accuracy compared to end-plane positioning; end-plane positioning has higher accuracy but is prone to detachment during actual milling, resulting in less secure positioning. Since milling meniscus aspherical lenses requires specialized tooling fixtures, the shape of these fixtures varies depending on the positioning method. With spherical positioning, the upper surface of the tooling fixture needs to be machined into a convex spherical surface to match the concave spherical surface of the meniscus lens. This limits the usability of the tooling fixture to lenses with similar spherical radii and apertures. With end-plane positioning, the upper surface of the tooling fixture is flat, allowing for the use of meniscus aspherical lenses with similar diameters. Commonly used machining methods rarely combine the advantages of both positioning methods.
[0005] Improving the positioning accuracy and stability of milling crescent-shaped aspherical parts, and maximizing the versatility of tooling fixtures, are urgent problems to be solved. Summary of the Invention
[0006] To address the aforementioned technical problems, this invention provides a processing apparatus and method for milling meniscus aspherical lenses.
[0007] The technical solution adopted in this invention is:
[0008] A processing apparatus for milling a meniscus aspherical lens includes at least a CNC milling machine, on which at least a grinding wheel spindle and a workpiece spindle are provided; it includes a base, an auxiliary block, and a diamond grinding wheel; the auxiliary block is detachably connected to the top of the base and is used to place the meniscus aspherical lens to be milled; a through hole is formed on the axial center line of the base and the auxiliary block; the diamond grinding wheel is mounted on the grinding wheel spindle and is placed above the meniscus aspherical lens to be milled during milling, for milling the meniscus aspherical lens placed on the auxiliary block; the base is connected to the workpiece spindle of the CNC milling machine.
[0009] The base is an integral structure consisting of a base positioning shaft, a base positioning end face, a connecting column, and a base outer cylinder arranged sequentially from bottom to top. The base positioning shaft and the base positioning end face are mounted on the workpiece spindle of a CNC milling machine. The base positioning shaft and the CNC milling machine spindle have the same clamping diameter and are connected with an H7 / h6 fit tolerance. The outer diameter of the base positioning end face is 1-3mm smaller than the end face of the CNC milling machine workpiece spindle. The outer diameter of the connecting column is larger than the outer diameter of the base outer cylinder. The outer diameter of the base positioning end face is larger than the outer diameter of the connecting column. Through holes are opened on the central axes of the base positioning shaft, the base positioning end face, the connecting column, and the base outer cylinder.
[0010] A base guide hole is opened on the central axis of the outer cylinder of the base. The inner diameter of the base guide hole is larger than the inner diameter of the through hole on the connecting column. The upper surface of the outer cylinder of the base is a horizontal part positioning surface. The upper side wall of the through hole on the connecting column is provided with a thread for detachable connection with the auxiliary block. The inner diameters of the base positioning shaft, the base positioning end face and the through hole on the connecting column are the same.
[0011] The outer diameter of the outer cylinder of the base is 1-2 mm smaller than the outer diameter of the meniscus aspherical lens to be milled.
[0012] The auxiliary block is an integral stainless steel or copper structure consisting of a threaded shaft, a guide shaft, and a support end arranged sequentially from bottom to top; a through hole is opened on the central axis of the threaded shaft, the guide shaft, and the support end; the outer diameter of the threaded shaft is smaller than the outer diameter of the guide shaft; the outer diameter of the support end is larger than the outer diameter of the guide shaft; a thread relief groove is provided at the connection between the threaded shaft and the guide shaft.
[0013] The supporting end is a spherical structure formed by a spherical end face and a spherical surface; the diameter of the spherical end face is larger than the outer diameter of the guide shaft; the spherical surface of the spherical end face matches the curvature of the concave spherical surface at the bottom of the meniscus aspherical lens to be milled.
[0014] The spherical cap is a convex spherical surface with a diameter 0.2 to 0.3 mm smaller than the concave spherical surface at the bottom of the meniscus aspherical lens to be milled.
[0015] The diamond grinding wheel includes a diamond grinding wheel layer, a diamond grinding wheel positioning end face, a diamond grinding wheel positioning shaft, and a connecting shaft; the diamond grinding wheel layer, connecting shaft, diamond grinding wheel positioning end face, and diamond grinding wheel positioning shaft are connected in sequence from bottom to top as an integral structure; a through grinding wheel cooling hole is opened on the central axis of the diamond grinding wheel layer, connecting shaft, diamond grinding wheel positioning end face, and diamond grinding wheel positioning shaft; the diamond grinding wheel positioning end face and diamond grinding wheel positioning shaft are mounted on the grinding wheel spindle of a CNC milling machine.
[0016] The diamond grinding wheel layer uses a bronze-bonded cup-shaped diamond grinding wheel.
[0017] A processing method for a milling apparatus for aspherical lenses, comprising the following steps:
[0018] Step 1: Design tooling and fixtures
[0019] The base and auxiliary blocks are designed according to the diameter of the meniscus aspherical lens to be milled and the radius of the sphere in the meniscus aspherical lens to be milled.
[0020] Step 2: Assemble the processing equipment for milling meniscus aspherical lenses.
[0021] The base and auxiliary block are connected by threads to form a tooling fixture;
[0022] Step 3: Inspect and number the parts.
[0023] For parts that have undergone one edge grinding process and are transferred to the milling of the meniscus aspherical surface process, the center thickness of all parts is measured with a thickness gauge and recorded one by one.
[0024] Step 4: Apply fake paint
[0025] Apply a protective dummy paint to the spherical surface of all the meniscus aspherical lenses to be milled and let it stand for more than 12 hours.
[0026] Step 5: Clamping the parts
[0027] Place the meniscus aspherical lens to be milled on the auxiliary block, and position it by milling the spherical end plane of the meniscus aspherical lens so that it contacts the top surface of the base; turn on the vacuum adsorption, and use a lever dial indicator to control the runout of the outer diameter of the part to 0.005~0.01mm.
[0028] Step Six: Apply Adhesive
[0029] Apply 502 glue to the contact position between the top surface of the base in the tooling fixture and the bottom of the spherical end plane of the meniscus aspherical lens to be milled for initial reinforcement;
[0030] Step 7: Clamp the meniscus aspherical lens to be milled.
[0031] Draw a mark line at the corresponding position of the tooling fixture and the spindle of the CNC milling machine. Ensure that the positioning reference is consistent in the same position each time the fixture is clamped. After waiting for 10 minutes, turn off the vacuum adsorption, remove the tooling fixture and the meniscus aspherical lens to be milled, invert it, and drip 502 glue into it through the through hole on the central axis of the base for further reinforcement. After 4-6 hours, it can be used. The clamping of the meniscus aspherical lens to be milled is now complete.
[0032] Step 8: Measure the total thickness of the meniscus aspherical lens to be milled and the tooling fixture, and record the thickness according to the number of the meniscus aspherical lens to be milled.
[0033] Step 9: Allocate processing allowance
[0034] Based on the measured thickness of the aspherical lens to be milled, the total thickness of the aspherical lens to be milled and the tooling fixture, and the finished thickness of the aspherical lens to be milled, a machining allowance of 0.02 to 0.03 mm is reserved for the polishing process. The total thickness of the aspherical lens to be milled and the tooling fixture at the finished product is calculated. The machining allowances for milling the surface closest to the sphere, rough milling the aspherical surface, and finish milling the aspherical surface are reasonably allocated. The corresponding total thickness dimensions of the parts and tooling fixtures are calculated and recorded.
[0035] Step 10: Milling and Grinding
[0036] Mount the meniscus aspherical lens to be milled and the tooling fixture onto the workpiece spindle of the CNC milling machine. Mount the diamond grinding wheel onto the milling spindle of the CNC milling machine. First, mill the surface closest to a sphere, with the radius R calculated according to formula 1-1, leaving a machining allowance of 0.25–0.3 mm. Then, use a coarse diamond grinding wheel to rough-grind the aspherical surface, leaving a machining allowance of 0.2–0.22 mm. Finally, use a fine diamond grinding wheel to finish-grind the aspherical surface. During the milling process, continuously use a profilometer to check and correct the surface, ensuring that the Pt value of the finished aspherical surface is less than 5. Leave a polishing allowance of 0.02 to 0.03 mm;
[0037] R= (1-1)
[0038] D – Diameter of the aspherical surface to be milled, in mm;
[0039] —Sagitta at half the diameter of the aspherical surface to be milled, i.e., the aspherical surface sagitta, mm;
[0040] Step 11: Polishing the parts
[0041] The milled meniscus aspherical lens and tooling fixture are polished together on a CNC polishing machine to ensure surface accuracy and center thickness. After completion, the meniscus aspherical lens and tooling fixture are immersed in acetone solution to detach the parts.
[0042] Step 12: Clean the parts and tooling fixtures.
[0043] Use cotton balls soaked in acetone to clean the meniscus aspherical lens and the tooling fixture; disassemble the base and auxiliary blocks of the tooling fixture and reassemble them according to the parts to be processed later;
[0044] Step Thirteen: Inspection
[0045] The meniscus aspherical lens is sent for inspection, and the lens center deviation is tested. It can generally be controlled within 1'.
[0046] Beneficial effects:
[0047] (1) This invention improves the positioning accuracy of the milling process of meniscus aspherical lenses by unifying the positioning reference and optimizing the tooling fixtures, increases the positioning firmness, maximizes the versatility of the tooling fixtures, and ultimately improves the lens center deviation accuracy of the milling process of meniscus aspherical lenses.
[0048] (2) In this invention, the spherical eccentricity of the crescent-shaped aspherical lens has been corrected by a grinding process before the milling process, and the perpendicularity requirement between the spherical end plane and the outer circle can be guaranteed.
[0049] (3) The lower end face of the base and the shaft and the upper end face of the base in this invention are machined by an external cylindrical grinding machine to ensure coaxiality and perpendicularity. The measured end face runout is within 0.002mm.
[0050] (4) In this invention, a marking line is drawn at the position corresponding to the spindle of the CNC milling machine. The part is clamped at the same position each time it is milled, eliminating the error of repeated positioning. The runout of the outer circle of the part is controlled within 0.005 to 0.01 mm using a lever dial indicator, which ensures that the positioning accuracy of the meniscus aspherical lens in the axial and horizontal directions is 0.01 mm or even higher, and ultimately improves the lens center deviation accuracy of the milled meniscus aspherical lens.
[0051] (5) This invention consists of a base and an auxiliary block. The base ensures the positioning accuracy of the meniscus aspherical lens, but the upper surface of the base is flat and lacks horizontal support, resulting in insufficient bonding of the parts and easy detachment under stress. The auxiliary block has a through hole in the center and a convex spherical surface formed by offsetting the spherical radius of the meniscus aspherical lens by 0.4 to 0.5 mm at its upper end. After the base and auxiliary block are connected by threads to form a tooling fixture, 502 glue is applied from the bottom of the base into the gap between the auxiliary block and the parts, enabling the parts to withstand horizontal forces and thus reinforcing them.
[0052] (6) The base and auxiliary block in this invention are designed to be detachable. For meniscus aspherical lenses with similar diameters but different radii, only the auxiliary block needs to be redesigned. The auxiliary block has a simple structure and is easy to replace, which can improve the versatility of the tooling fixture. By serializing and customizing the base, many types of meniscus aspherical lenses can be processed.
[0053] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description
[0054] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0055] Figure 1 This is a schematic diagram of the structure of the present invention.
[0056] Figure 2 This is a schematic diagram of the base.
[0057] Figure 3 This is a schematic diagram of the auxiliary block.
[0058] Figure 4 This is a schematic diagram of a meniscus aspherical lens.
[0059] Figure 5 This is a schematic diagram of a diamond grinding wheel.
[0060] Figure 6 This is a diagram showing the location where 502 glue is used for reinforcement.
[0061] Figure 7 This is a schematic diagram of the milling process of the present invention.
[0062] Figure 8This is a schematic diagram of the process flow for milling a meniscus aspherical lens using a CNC milling machine.
[0063] In the diagram: 1. Base; 2. Auxiliary block; 3. Meniscus aspherical lens to be milled; 4. Diamond grinding wheel; 5. 502 glue reinforcement position; 1-1. Base positioning shaft; 1-2. Base guide hole; 1-3. Part positioning surface; 1-4. Base outer cylinder; 1-5. Thread; 1-6. Base positioning end face; 1-7. Connecting column; 2-1. Threaded shaft; 2-2. Guide shaft; 2-3. Spherical crown surface; 2-4. Spherical crown end face; 2-5 3-1. Through hole; 3-2. Spherical end face; 3-3. Outer cylindrical surface; 3-4. Aspherical surface; 3-5. Spherical surface; 4-1. Diamond grinding wheel layer; 4-2. Diamond grinding wheel positioning end face; 4-3. Diamond grinding wheel positioning shaft; 4-4. Grinding wheel cooling hole; 4-5. Connecting shaft; 5-1. Fixing the tooling fixture and parts in position on the spindle of the CNC milling machine using 502 glue; 5-2. Fixing the tooling fixture and parts in position after removal using 502 glue.
[0064] Figure 8 In the middle: a) Schematic diagram of the processing device for positioning and reinforcing the meniscus aspherical lens and milling the meniscus aspherical lens; b) Schematic diagram of the completed milling of the meniscus aspherical lens, which is closest to the spherical surface; c) Schematic diagram of the completed aspherical milling of the meniscus aspherical lens. Detailed Implementation
[0065] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0066] Example 1:
[0067] according to Figures 1-8 The apparatus shown is for milling a meniscus aspherical lens, comprising at least a CNC milling machine, which has at least a grinding wheel spindle and a workpiece spindle; it includes a base 1, an auxiliary block 2, and a diamond grinding wheel 4; the auxiliary block 2 is detachably connected to the top of the base 1 and is used to place the meniscus aspherical lens 3 to be milled; a through hole is formed on the axial center line of the base 1 and the auxiliary block 2; the diamond grinding wheel 4 is mounted on the grinding wheel spindle and is placed above the meniscus aspherical lens 3 to be milled during milling, for milling the meniscus aspherical lens 3 placed on the auxiliary block 2; the base 1 is connected to the workpiece spindle of the CNC milling machine.
[0068] In actual use, the base 1 and auxiliary block 2 form a tooling fixture. The meniscus aspherical lens 3 to be milled is positioned by the base 1, and the auxiliary block 2 provides support. The part, i.e., the meniscus aspherical lens 3 to be milled, is bonded and clamped together with 502 glue. The aspherical surface is milled on a CNC milling machine using a diamond grinding wheel 4, controlling the milling surface accuracy and center thickness, etc. After passing inspection, the part and tooling fixture are transferred to the polishing process. After passing polishing, the part and tooling fixture are immersed in acetone solution to separate the part and tooling fixture. The part and tooling fixture are wiped with cotton balls soaked in acetone solution, according to the shape of the meniscus aspherical lens to be processed next.
[0069] In practical applications, the base 1 and the auxiliary block 2 can be disassembled. For the meniscus aspherical lens 3 to be milled with similar diameters but different spherical radii, only the auxiliary block 2 needs to be redesigned. The auxiliary block 2 has a simple structure and is easy to replace, which can improve the versatility of tooling fixtures.
[0070] Example 2:
[0071] according to Figures 1-8 The processing device for milling a meniscus aspherical lens shown differs from Embodiment 1 in that: the base 1 is an integral structure composed of a base positioning shaft 1-1, a base positioning end face 1-6, a connecting column 1-7, and a base outer cylinder 1-4 arranged sequentially from bottom to top; the base positioning shaft 1-1 and the base positioning end face 1-6 are mounted on the workpiece spindle of a CNC milling machine; the base positioning shaft 1-1 and the CNC milling machine spindle have the same clamping diameter and are connected with an H7 / h6 fit tolerance; the outer diameter of the base positioning end face 1-6 is 1-3 mm smaller than the end face of the CNC milling machine workpiece spindle; the outer diameter of the connecting column 1-7 is larger than the outer diameter of the base outer cylinder 1-4; the outer diameter of the base positioning end face 1-6 is larger than the outer diameter of the connecting column 1-7; and a through hole is opened on the central axis of the base positioning shaft 1-1, the base positioning end face 1-6, the connecting column 1-7, and the base outer cylinder 1-4.
[0072] Furthermore, a base guide hole 1-2 is opened on the central axis of the outer cylinder 1-4 of the base. The inner diameter of the base guide hole 1-2 is larger than the inner diameter of the through hole on the connecting column 1-7. The upper surface of the outer cylinder 1-4 of the base is a horizontal part positioning surface 1-3. A thread 1-5 for detachable connection with the auxiliary block 2 is provided on the upper side wall of the through hole on the connecting column 1-7. The inner diameters of the through holes on the base positioning shaft 1-1, the base positioning end face 1-6, and the connecting column 1-7 are the same.
[0073] Furthermore, the outer diameter of the outer cylinder 1-4 of the base is 1-2 mm smaller than the outer diameter of the meniscus aspherical lens 3 to be milled.
[0074] In practical use, the base positioning shaft 1-1 mates with the CNC milling machine spindle (generally using an H7 / h6 fit tolerance), and the base positioning end face 1-6 fits against the end face of the CNC milling machine spindle, positioning the base on the CNC milling machine spindle. The base guide hole 1-2 and thread 1-5 are... Figure 3 The guide shaft 2-2 and the threaded shaft 2-1 mate, and the part positioning surface 1-3 is aligned with... Figure 3 The end faces 2-4 of the middle spherical crown fit together, fixing the auxiliary block 2 to the base 1 and facilitating disassembly. The diameter of the outer cylinder 1-4 of the base is generally larger than... Figure 4 The diameter of the outer cylindrical surface 3-2 of the middle part is 1-2 mm smaller, which makes the 502 glue bonding stronger. The base positioning shaft 1-1, the base positioning end face 1-6 and the part positioning surface 1-3 need to be machined on an external cylindrical grinding machine to ensure the coaxiality of the base and the circular runout of the end face.
[0075] In this embodiment, the base material is stainless steel, and the base 1 has a through hole in the center to facilitate the use of vacuum adsorption. The lower end face of the base 1 and the shaft and the upper end face of the base need to be machined by an external cylindrical grinder to ensure coaxiality and perpendicularity.
[0076] Example 3:
[0077] according to Figures 1-8 The processing device for milling a meniscus aspherical lens shown differs from Embodiment 1 in that: the auxiliary block 2 is an integral stainless steel or copper structure composed of a threaded shaft 2-1, a guide shaft 2-2, and a support end arranged sequentially from bottom to top; a through hole is opened on the central axis of the threaded shaft 2-1, the guide shaft 2-2, and the support end; the outer diameter of the threaded shaft 2-1 is smaller than the outer diameter of the guide shaft 2-2; the outer diameter of the support end is larger than the outer diameter of the guide shaft 2-2; and a threaded relief groove is provided at the connection between the threaded shaft 2-1 and the guide shaft 2-2.
[0078] Furthermore, the supporting end is a spherical structure formed by the spherical end face 2-4 and the spherical surface 2-3; the diameter of the spherical end face 2-4 is greater than the outer diameter of the guide shaft 2-2; the spherical surface 2-3 matches the concave spherical curvature of the bottom of the meniscus aspherical lens 3 to be milled.
[0079] Furthermore, the spherical cap 2-3 is a convex spherical surface with a radius 0.4-0.5 mm smaller than the concave spherical surface at the bottom of the meniscus aspherical lens 3 to be milled.
[0080] In practical use, threaded shaft 2-1, guide shaft 2-2 and... Figure 2 The guide hole 1-2 of the middle base is fitted with thread 1-5, and the end face 2-4 of the spherical crown is fitted with... Figure 2 The positioning surfaces 1-3 of the middle part fit together, fixing the auxiliary block 2 to the base 1 and making it easy to disassemble. The spherical radius of the spherical surface 2-3 of the spherical crown is determined by... Figure 4The spherical surface 3-4 of the middle part is offset by 0.4-0.5mm to form a convex spherical surface, which facilitates the filling of 502 glue. The diameter of the through hole 2-5 does not exceed Figure 4 The radius of the spherical surface 3-4 of the middle part corresponds to 1 / 3 of the aperture. The upper part of the auxiliary block 2 is a convex spherical surface formed by offsetting the spherical aperture of the meniscus aspherical lens by 0.4 to 0.5 mm. Below it are the guide shaft 2-2 and the threaded shaft 2-1, which mate with the base 1. The guide shaft 2-2 needs to be cleaned at the corners.
[0081] Example 4:
[0082] according to Figures 1-8 The processing device for milling a meniscus aspherical lens shown differs from Embodiment 1 in that: the diamond grinding wheel 4 includes a diamond grinding wheel layer 4-1, a diamond grinding wheel positioning end face 4-2, a diamond grinding wheel positioning shaft 4-3, and a connecting shaft 4-5; the diamond grinding wheel layer 4-1, the connecting shaft 4-5, the diamond grinding wheel positioning end face 4-2, and the diamond grinding wheel positioning shaft 4-3 are connected in an integral structure from bottom to top; a through grinding wheel cooling hole 4-4 is opened on the central axis of the diamond grinding wheel layer 4-1, the connecting shaft 4-5, the diamond grinding wheel positioning end face 4-2, and the diamond grinding wheel positioning shaft 4-3; the diamond grinding wheel positioning end face 4-2 and the diamond grinding wheel positioning shaft 4-3 are mounted on the grinding wheel spindle of a CNC milling machine.
[0083] Furthermore, the diamond grinding wheel layer 4-1 uses a bronze-bonded cup-shaped diamond grinding wheel.
[0084] In actual use, the diamond grinding wheel positioning end face 4-2 and the diamond grinding wheel positioning shaft 4-3 are installed on the grinding wheel spindle of the CNC milling machine, and the diamond grinding wheel layer 4-1 is used for milling parts.
[0085] In practical applications, the diamond grinding wheel layer 4-1 can be designed with different diameter specifications according to the size of the part to be milled, thereby customizing the diamond grinding wheel 4 that meets the requirements.
[0086] Example 5:
[0087] Reference Figures 1-8 A processing method for a milling apparatus for aspherical lenses, comprising the following steps:
[0088] Step 1: Design tooling and fixtures
[0089] The base 1 and auxiliary block 2 are designed according to the diameter of the meniscus aspherical lens 3 to be milled and the radius of the spherical surface 3-4 in the meniscus aspherical lens 3 to be milled;
[0090] Step 2: Assemble the processing equipment for milling meniscus aspherical lenses.
[0091] The base 1 and the auxiliary block 2 are connected by threads to form a tooling fixture;
[0092] Step 3: Inspect and number the parts.
[0093] For parts that have undergone one edge grinding process and are transferred to the milling of the meniscus aspherical surface process, the center thickness of all parts is measured with a thickness gauge and recorded one by one.
[0094] Step 4: Apply fake paint
[0095] Apply a layer of protective dummy paint to the spherical surfaces 3-4 of all the meniscus aspherical lenses 3 to be milled, and let them stand for more than 12 hours.
[0096] Step 5: Clamping the parts
[0097] Place the meniscus aspherical lens 3 to be milled on the auxiliary block 2, and position it by the spherical end plane 3-1 of the meniscus aspherical lens 3 to be milled, so that it contacts the top surface of the base 1; turn on the vacuum adsorption, and use a lever dial indicator to control the runout of the outer circle of the part to 0.005~0.01mm.
[0098] Step Six: Apply Adhesive
[0099] Apply 502 glue to the contact position between the top surface of the base 1 and the bottom of the spherical end plane 3-1 of the meniscus aspherical lens 3 to be milled in the tooling fixture for preliminary reinforcement;
[0100] Step 7: Clamp the meniscus aspherical lens to be milled 3
[0101] Draw a marking line at the corresponding position of the tooling fixture and the spindle of the CNC milling machine. Ensure that the positioning reference is consistent in the same position each time the fixture is clamped. After waiting for 10 minutes, turn off the vacuum adsorption, remove the tooling fixture and the meniscus aspherical lens 3 to be milled, invert it, and drip 502 glue into it through the through hole on the central axis of the base 1 for further reinforcement. After 4-6 hours, it can be used. The clamping of the meniscus aspherical lens 3 to be milled is now complete.
[0102] Step 8: Measure the total thickness of the meniscus aspherical lens 3 to be milled and the tooling fixture, and record the thickness according to the number of the meniscus aspherical lens 3 to be milled.
[0103] Step 9: Allocate processing allowance
[0104] Based on the measured thickness of the aspherical lens 3 to be milled, the total thickness of the aspherical lens 3 to be milled and the tooling fixture, and the finished thickness of the aspherical lens 3 to be milled, a machining allowance of 0.02 to 0.03 mm is reserved for the polishing process. The corresponding total thickness of the aspherical lens 3 to be milled and the tooling fixture at the finished product is calculated. The machining allowances for milling the surface closest to the sphere, rough milling the aspherical surface, and fine milling the aspherical surface are reasonably allocated. The corresponding total thickness dimensions of the part and tooling fixture are calculated and recorded.
[0105] Step 10: Milling and Grinding
[0106] Mount the meniscus aspherical lens 3 to be milled and the tooling fixture onto the workpiece spindle of the CNC milling machine. Mount the diamond grinding wheel 4 onto the milling spindle of the CNC milling machine. First, mill the surface closest to the sphere, with the radius R calculated according to formula 1-1, leaving a machining allowance of 0.25-0.3 mm. Then, use a coarse diamond grinding wheel to rough grind the aspherical surface 3-3, leaving a machining allowance of 0.2-0.22 mm. Finally, use a fine diamond grinding wheel to finish grinding the surface of the aspherical surface 3-3. During the milling process, continuously use a profilometer to check and correct the surface, ensuring that the Pt value of the finished aspherical surface 3-3 is less than 5. Leave a polishing allowance of 0.02 to 0.03 mm;
[0107] R= (1-1)
[0108] D – Diameter of the aspherical surface to be milled, in mm;
[0109] —Sagitta at half the diameter of the aspherical surface to be milled, i.e., the aspherical surface sagitta, mm;
[0110] Step 11: Polishing the parts
[0111] The milled meniscus aspherical lens and tooling fixture are polished together on a CNC polishing machine to ensure surface accuracy and center thickness. After completion, the meniscus aspherical lens and tooling fixture are immersed in acetone solution to detach the parts.
[0112] Step 12: Clean the parts and tooling fixtures.
[0113] The meniscus aspherical lens and tooling fixture are cleaned with cotton balls soaked in acetone solution; the tooling fixture is disassembled from the base 1 and auxiliary block 2 and reassembled according to the parts to be processed later;
[0114] Step Thirteen: Inspection
[0115] The meniscus aspherical lens is sent for inspection, and the lens center deviation is tested. It can generally be controlled within 1'.
[0116] In practical use, the aspherical lens 3 to be milled undergoes the following processes: blanking, end face flattening, rubber strip rounding, rough grinding of the concave spherical surface, fine grinding of the concave spherical surface, polishing of the concave spherical surface (leaving a machining allowance of 0.3-0.4mm), and one edge grinding (to correct the perpendicularity of the end face and outer circle, and the eccentricity of the spherical surface). During the entire processing flow, the spherical end face and outer circle perpendicularity, as well as the eccentricity of the spherical surface, are corrected through one edge grinding process. The base positioning shaft, base positioning end face, and part positioning surface of the tooling fixture need to be machined on an external cylindrical grinding machine to ensure the coaxiality of the base and the circular runout of the end face. A marking line is drawn at the corresponding position on the tooling fixture and the CNC milling machine spindle, ensuring that the positioning datum is consistent in the same position each time the fixture is clamped. This improves the accuracy of the tooling fixture, the accuracy of the part, and the repeatability of positioning, ultimately improving the lens center deviation accuracy of the milled aspherical lens.
[0117] In the processing device used in this invention, there is a certain gap between the auxiliary block and the meniscus aspherical lens. Filling this gap with 502 glue ensures a tight bond between the part and the tooling, and no part has detached during actual use. During bonding, the 502 glue reinforcement positions 5 include position 5-1 where the tooling fixture and part are fixed with 502 glue on the CNC milling machine spindle, and position 5-2 where the tooling fixture and part are fixed with 502 glue after removal. To fix the tooling fixture and part with 502 glue at position 5-2, the tooling fixture and part need to be inverted, and 502 glue is dripped into the center hole of the base, filling the gap between the part and the auxiliary block.
[0118] The base and auxiliary block are detachable. For meniscus aspherical lenses with similar diameters but different radii, only the auxiliary block needs to be redesigned. The auxiliary block has a simple structure and is easy to replace, which improves the versatility of tooling fixtures. By serializing and customizing the base, many types of meniscus aspherical lenses can be manufactured.
[0119] The processing technology and equipment provided by this invention have been successfully used on our LGS200 and MCG250 CNC milling machines with excellent results. This method is applicable to all optical CNC precision machining equipment and can be extended to other types of optical spherical lenses.
[0120] Where there is no conflict, those skilled in the art can combine the relevant technical features in the above examples according to the actual situation to achieve the corresponding technical effects. Specific details of the various combinations will not be elaborated here.
[0121] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.
[0122] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.
[0123] The above description is merely a preferred embodiment of the present invention. The present invention is not limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Any simple modifications, equivalent variations, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the present invention. 。
Claims
1. A processing method for a milling apparatus for meniscus aspherical lenses, characterized in that: A processing device for milling meniscus aspherical lenses is provided. The processing device for milling meniscus aspherical lenses includes at least a CNC milling machine, which is equipped with at least a grinding wheel spindle and a workpiece spindle. It also includes a base (1), an auxiliary block (2), and a diamond grinding wheel (4). The auxiliary block (2) is detachably connected to the top of the base (1) and is used to place the meniscus aspherical lens (3) to be milled. A through hole is opened on the axial center line of the base (1) and the auxiliary block (2). The diamond grinding wheel (4) is installed on the grinding wheel spindle and is placed above the meniscus aspherical lens (3) to be milled during milling. It is used to mill the meniscus aspherical lens (3) placed on the auxiliary block (2). The base (1) is connected to the workpiece spindle of the CNC milling machine. The base (1) is an integral structure consisting of a base positioning shaft (1-1), a base positioning end face (1-6), a connecting column (1-7), and a base outer cylinder (1-4) arranged sequentially from bottom to top; through holes are opened on the central axis of the base positioning shaft (1-1), the base positioning end face (1-6), the connecting column (1-7), and the base outer cylinder (1-4); The base outer cylinder (1-4) has a base guide hole (1-2) on its central axis. The inner diameter of the base guide hole (1-2) is larger than the inner diameter of the through hole on the connecting column (1-7). The upper surface of the base outer cylinder (1-4) is a horizontal part positioning surface (1-3). The upper side wall of the through hole on the connecting column (1-7) is provided with a thread (1-5) for detachable connection with the auxiliary block (2). The inner diameters of the through holes on the base positioning shaft (1-1), the base positioning end face (1-6), and the connecting column (1-7) are the same. The auxiliary block (2) is an integral stainless steel or copper structure consisting of a threaded shaft (2-1), a guide shaft (2-2), and a support end arranged sequentially from bottom to top; through holes are opened on the central axis of the threaded shaft (2-1), the guide shaft (2-2), and the support end; the outer diameter of the threaded shaft (2-1) is smaller than the outer diameter of the guide shaft (2-2); the outer diameter of the support end is larger than the outer diameter of the guide shaft (2-2); a threaded relief groove is provided at the connection between the threaded shaft (2-1) and the guide shaft (2-2); The steps are as follows: Step 1: Design tooling and fixtures The base (1) and auxiliary block (2) are designed according to the diameter of the meniscus aspherical lens (3) to be milled and the radius of the spherical surface (3-4) in the meniscus aspherical lens (3) to be milled. Step 2: Assemble the processing equipment for milling meniscus aspherical lenses. The base (1) and the auxiliary block (2) are connected by threads to form a tooling fixture; Step 3: Inspect and number the parts. For parts that have undergone one edge grinding process and are transferred to the milling of the meniscus aspherical surface process, the center thickness of all parts is measured with a thickness gauge and recorded one by one. Step 4: Apply fake paint Apply a layer of protective dummy paint to the spherical surface (3-4) of all the meniscus aspherical lenses (3) to be milled, and let it stand for more than 12 hours; Step 5: Clamping the parts Place the aspherical lens (3) to be milled on the auxiliary block (2), and position it by the spherical end plane (3-1) of the aspherical lens (3) to be milled, so that it contacts the top surface of the base (1); turn on the vacuum adsorption, and use a lever dial indicator to control the runout of the outer circle of the part to 0.005~0.01mm; Step Six: Apply Adhesive Apply 502 glue to the contact position between the top surface of the base (1) in the tooling fixture and the bottom of the spherical end plane (3-1) of the meniscus aspherical lens (3) to be milled, for preliminary reinforcement; Step 7: Clamp the meniscus aspherical lens to be milled (3) Draw a mark line at the corresponding position of the tooling fixture and the spindle of the CNC milling machine. Each time the fixture is clamped, the positioning reference is unified at the same position. After waiting for 10 minutes, turn off the vacuum adsorption, remove the tooling fixture and the meniscus aspherical lens (3) to be milled, invert it and drip 502 glue into the through hole on the central axis of the base (1) for further reinforcement. After 4-6 hours, it can be used. The clamping of the meniscus aspherical lens (3) to be milled is completed. Step 8: Measure the total thickness of the meniscus aspherical lens (3) to be milled and the tooling fixture, and record the thickness according to the number of the meniscus aspherical lens (3) to be milled; Step 9: Allocate processing allowance Based on the measured thickness of the aspherical lens (3) to be milled, the total thickness of the aspherical lens (3) to be milled and the tooling fixture, and the finished thickness of the aspherical lens (3) to be milled, a machining allowance of 0.02 to 0.03 mm is reserved for the polishing process. The corresponding thickness of the aspherical lens (3) to be milled and the tooling fixture at the time of completion is calculated. The machining allowances for milling the surface closest to the sphere, rough milling of the aspherical surface, and fine milling of the aspherical surface are reasonably allocated. The corresponding total thickness dimensions of the parts and tooling fixture are calculated and recorded. Step 10: Milling and Grinding The meniscus aspherical lens (3) to be milled and the tooling fixture are installed on the workpiece spindle of the CNC milling machine, and the diamond grinding wheel (4) is installed on the milling spindle of the CNC milling machine. First, the surface closest to the sphere is milled, and the radius R of the surface closest to the sphere is calculated according to formula 1-1. A machining allowance of 0.25-0.3 mm is reserved. Then, the aspherical surface is rough ground with a coarse diamond grinding wheel, with a machining allowance of 0.2-0.22 mm reserved. Finally, the aspherical surface is finely ground with a fine diamond grinding wheel. During the milling process, a profilometer is used to continuously detect and correct the surface to ensure that the Pt value of the finely ground aspherical surface is less than 5. ; Leave a polishing allowance of 0.02 to 0.03 mm; R= (1-1) D – Diameter of the aspherical surface to be milled, in mm; —Sagitta at half the diameter of the aspherical surface to be milled, i.e., the aspherical surface sagitta, mm; Step 11: Polishing the parts The milled meniscus aspherical lens and tooling fixture are polished together on a CNC polishing machine to ensure surface accuracy and center thickness. After completion, the meniscus aspherical lens and tooling fixture are immersed in acetone solution to detach the parts. Step 12: Clean the parts and tooling fixtures. The meniscus aspherical lens and tooling fixture are cleaned with cotton balls soaked in acetone solution; the tooling fixture is disassembled from the base (1) and auxiliary block (2) and reassembled according to the parts to be processed later; Step Thirteen: Inspection The meniscus aspherical lens is sent for inspection, and the lens center deviation is tested. It can generally be controlled within 1'.
2. The processing method of the milling apparatus for meniscus aspherical lenses as described in claim 1, characterized in that: The base positioning shaft (1-1) and the base positioning end face (1-6) are mounted on the workpiece spindle of the CNC milling machine; the base positioning shaft (1-1) and the CNC milling machine spindle have the same clamping diameter and are connected with an H7 / h6 fit tolerance; the outer diameter of the base positioning end face (1-6) is 1-3mm smaller than the end face of the CNC milling machine workpiece spindle; the outer diameter of the connecting column (1-7) is larger than the outer diameter of the base outer cylinder (1-4); the outer diameter of the base positioning end face (1-6) is larger than the outer diameter of the connecting column (1-7).
3. The processing method of the milling apparatus for meniscus aspherical lenses as described in claim 1, characterized in that: The outer diameter of the outer cylinder (1-4) of the base is 1-2 mm smaller than the outer diameter of the meniscus aspherical lens (3) to be milled.
4. The processing method of the milling apparatus for meniscus aspherical lenses as described in claim 1, characterized in that: The supporting end is a spherical structure formed by the spherical end face (2-4) and the spherical surface (2-3); the diameter of the spherical end face (2-4) is greater than the outer diameter of the guide shaft (2-2); the spherical surface (2-3) matches the concave spherical curvature of the bottom of the meniscus aspherical lens (3) to be milled.
5. The processing method of the milling apparatus for meniscus aspherical lenses as described in claim 4, characterized in that: The spherical cap (2-3) is a convex spherical surface with a radius 0.4 to 0.5 mm smaller than the concave spherical radius at the bottom of the meniscus-shaped aspherical lens (3) to be milled.
6. The processing method of the milling apparatus for meniscus aspherical lenses as described in claim 1, characterized in that: The diamond grinding wheel (4) includes a diamond grinding wheel layer (4-1), a diamond grinding wheel positioning end face (4-2), a diamond grinding wheel positioning shaft (4-3), and a connecting shaft (4-5); the diamond grinding wheel layer (4-1), the connecting shaft (4-5), the diamond grinding wheel positioning end face (4-2), and the diamond grinding wheel positioning shaft (4-3) are connected in sequence from bottom to top as an integral structure; a through grinding wheel cooling hole (4-4) is opened on the central axis of the diamond grinding wheel layer (4-1), the connecting shaft (4-5), the diamond grinding wheel positioning end face (4-2), and the diamond grinding wheel positioning shaft (4-3); the diamond grinding wheel positioning end face (4-2) and the diamond grinding wheel positioning shaft (4-3) are mounted on the grinding wheel spindle of a CNC milling machine.
7. The processing method of the milling apparatus for meniscus aspherical lenses as described in claim 6, characterized in that: The diamond grinding wheel layer (4-1) uses a bronze-bonded cup-shaped diamond grinding wheel.