Air pressure regulated film medium modification super-smooth machining device and machining method

Abstract

The application discloses a kind of air pressure regulated film medium modification and ultra-smooth processing device and method, and the lower drive module of processing device includes from bottom to top: platform drive motor, polishing platform, pneumatic chuck, film medium, and the auxiliary device of pneumatic chuck includes vacuum generator, filter, gas flow meter and reversing valve.The upper drive module of processing device includes from top to bottom: drive motor, pedestal, buffer medium and the element to be polished.The application has the characteristics of low cost and simple operation, based on the regulation distribution of film medium contact pressure on element and the catalytic reaction of film medium, the modification polishing and ultra-smooth processing of element are completed under certain parameters, without causing surface damage, and finally obtaining non-damage ultra-smooth optical element.

Description

Technical Field

[0001] This invention relates to the field of precision machining technology for optical components, and in particular to a film dielectric shaping, polishing and ultra-smooth processing device and method based on air pressure regulation, which enables high-precision, ultra-smooth and damage-free manufacturing of optical components, especially optical glass and semiconductor components. Background Technology

[0002] With the advancement of optical processing technology, the requirements for optical systems and optical components in fields such as laser fusion, space communication, precision lithography, and precision guidance are gradually increasing. Optical components are required to have nanometer-level surface accuracy, picometer-level ultra-smooth surfaces, and near-defect-free surface quality.

[0003] Currently, methods for achieving high-precision, ultra-smooth surfaces on optical components include chemical mechanical polishing (CMP), magnetorheological polishing (MRP), ion beam polishing (IB), and airbag polishing. CMP removes material under pressure through the plowing and grinding action of hard particles. While ultra-smooth surfaces can be achieved to some extent by adjusting polishing parameters and using nanoscale abrasives, nanoscale abrasives are expensive, prone to agglomeration, and require complex process control. Furthermore, their high hardness inevitably leads to scratches and pits on the component surface. Magnetorheological and IB polishing equipment is expensive, and post-processing issues such as iron powder residue and ion implantation further affect the component surface quality. Airbag polishing uses a single, uniform pressure distribution, resulting in insufficient adaptability to medium deformation and significant edge effects.

[0004] US patent 10199242 discloses a method for processing silicon carbide components by depositing a platinum thin film on the surface of a polishing pad, achieving a root mean square surface roughness of 0.228 nm. However, the platinum thin film deposition on the polishing pad is costly, and platinum residue on the optical component surface is difficult to completely remove; it also does not address the reshaping and polishing of the component. CN119238385A discloses a polishing disk and its preparation method, which embeds metal nanoparticles in a fusible material to obtain a sub-angstrom-level surface. However, metal nanoparticles are prone to agglomeration, forming large particles that cause particle scratches, and it is difficult to control the uniform distribution of particles in fusible materials. This method also does not address how to perform reshaping and polishing of the component. CN102873648A discloses a partitioned air cushion polishing pad with different polishing pressures in different areas controlled by an air-filled film. This achieves independent control of the pressure of the multi-partition polishing pad and realizes partitioned pressure regulation and shaping, overcoming the problem of insufficient or excessive polishing in some areas caused by a single structure. However, in this solution, the polishing pad is a polishing fabric or abrasive, which uses abrasive particles and may introduce scratches and other damage. Furthermore, it does not mention the roughness of the components and cannot obtain an ultra-smooth surface.

[0005] Therefore, there is an urgent need to propose a processing method that can achieve low-cost, high-precision shaping and polishing, ultra-smooth processing, and damage-free processing of optical components to meet the growing demand for high-end applications of optical components. Summary of the Invention

[0006] To overcome the shortcomings of the existing technology, the present invention aims to propose a pressure-controlled membrane medium shaping, polishing, and ultra-smooth processing apparatus and method. By controlling the deformation amplitude of the membrane medium through pressure regulation and controlling the contact pressure distribution between the membrane medium and the component, the component is shaped and polished to achieve nanometer-level surface accuracy. Furthermore, the membrane medium itself acts as a catalyst, achieving material removal through a catalytic chemical reaction with the optical component material, avoiding problems such as pits, scratches, iron powder residue, and ion implantation caused by existing polishing methods, resulting in a picometer-level ultra-smooth surface. This invention features low cost, simple operation, and safety and reliability, achieving high-precision, ultra-smooth, and damage-free optical components through pressure-controlled membrane medium shaping, polishing, and ultra-smooth processing.

[0007] The technical solution of the present invention is as follows:

[0008] A pressure-controlled membrane dielectric shaping and ultra-smooth processing apparatus, characterized in that it includes a lower drive module, an upper drive module, auxiliary devices, and a polishing solution supply system, wherein...

[0009] The lower drive module includes, from bottom to top, the following components:

[0010] The platform drive motor has its output shaft rigidly connected to the center of the polishing platform via a coupling.

[0011] The polishing platform has a pneumatic suction cup fixedly connected to its upper surface by bolts.

[0012] The pneumatic suction cup is a ring-shaped disc with multiple concentric ring sections on its upper surface. Each section has multiple micropores evenly distributed within its ring band, and each section is connected to an auxiliary device via an independent air tube.

[0013] The membrane medium is adsorbed and flattened onto the upper surface of the pneumatic suction cup by negative pressure;

[0014] The upper driving module, from top to bottom, includes:

[0015] The base drive motor has its output shaft coaxially connected to the center of the top of the base via a flange.

[0016] The base is cylindrical, and the bottom is fixed to the buffer medium with adhesive.

[0017] A buffer medium, the lower surface of which is fixed to the element to be polished by vacuum adsorption;

[0018] The auxiliary device includes:

[0019] The vacuum generator is connected to the main air inlet pipe of the pneumatic suction cup via the main air pipe;

[0020] Gas flow meters are installed on the gas pipes of each zone branch to control gas pressure;

[0021] A reversing valve is installed at the end of the air pipe in each zone branch and is used to switch between inhalation and exhalation modes.

[0022] The polishing solution supply system has a drip nozzle located above the interface between the membrane medium and the element to be polished.

[0023] The polishing platform is used to support the pneumatic suction cup and the film medium. The material is stainless steel or aluminum, and the flatness is ≤50μm. The surface flatness of the pneumatic suction cup is ≤10μm, and the material of the pneumatic suction cup is aluminum oxide or silicon carbide.

[0024] The surface of the pneumatic suction cup is divided into n partitions according to radius, where n ranges from 3 to 10, and the radius of each partition is denoted as R. i (i = 1, ..., n), each partition has micropores within its annular band, with diameters ranging from 100 μm to 1 mm. The number of micropores in each partition does not exceed (R). i 2 -R i-1 2 ) / 2, (i = 2, ..., n).

[0025] The membrane medium is a layer of metal sheet / foil adhered to the surface of the pneumatic suction cup. The metal is a transition metal of group VIIB, VIII and IB, including nickel, ruthenium, manganese and copper, etc., and the purity is not less than 99.9%. The thickness of the membrane medium is 0.01 to 0.05 mm.

[0026] The polishing solution includes a polishing solvent, wherein the polishing solvent is deionized water with a resistivity greater than or equal to 15 MΩ·cm.

[0027] The base material of the upper drive module is stainless steel, aluminum, etc. The upper part of the base is fixedly coaxially connected to the drive motor, and the buffer medium is fixedly connected to the lower surface of the base. The buffer medium is made of polyurethane, damping cloth, non-woven fabric or sponge, etc.

[0028] A method for shaping and ultra-smooth processing of membrane media with controlled air pressure, characterized by comprising:

[0029] Shaping and polishing stage:

[0030] The component to be polished is fixed on the lower surface of the buffer medium, and a load pressure of 15-40 kPa is applied.

[0031] The polishing solution is added dropwise to the interface between the element to be polished and the membrane medium at a drop rate of 1–10 ml / min.

[0032] Start the platform drive motor and the base drive motor to control the speed of the polishing platform and the component to be polished to 50-80 rpm;

[0033] By adjusting the air pressure and airflow direction of each section of the pneumatic suction cup using an auxiliary device, the deformation δ of the membrane medium is matched conjugately with the surface shape error of the component. The formula for the deformation δ of the membrane medium is as follows:

[0034]

[0035] Where ΔP is the pressure difference across the membrane medium, R is the micropore radius, E is the elastic modulus of the membrane medium material, ν is the Poisson's ratio of the membrane medium material, and D is the bending stiffness of the membrane medium.

[0036] Dynamically adjust the air pressure and continuously refine and polish the surface until the root mean square value of the component surface is ≤10nm;

[0037] Ultra-smooth processing stage:

[0038] Reduce the load pressure to 10–20 kPa and adjust the polishing solution drop rate to 1–5 ml / min.

[0039] Control the rotation speed of the component to be polished and the polishing platform to 10-30 rpm, and make the component reciprocate eccentrically for 10-25 mm along the radial direction of the pneumatic suction cup;

[0040] The pneumatic suction cup is set to uniform suction in all zones, with an air pressure of 0.01–0.02 MPa, and atomic-level material removal is achieved by utilizing the catalytic effect of the membrane medium.

[0041] Continue polishing until the root mean square value of the component surface roughness is ≤0.1nm.

[0042] The method for shaping and ultra-smooth processing of membrane media with air pressure regulation is characterized in that, in the shaping and polishing stage, the air pressure regulation of the pneumatic suction cup is specifically set as follows: the suction pressure is set to 0.015-0.03 MPa for the corresponding zone of the concave area of ​​the component surface, and the blowing pressure is set to 0.03-0.05 MPa for the corresponding zone of the convex area of ​​the component surface.

[0043] The gas pressure-controlled membrane medium shaping and ultra-smooth processing method is characterized in that, when the membrane medium is nickel foil, 5 wt% hydrogen peroxide is added to the polishing solution and the pH value is adjusted to 3-5.

[0044] An optical element, processed by the above method, has a surface shape root mean square value ≤10nm, a roughness root mean square value ≤0.1nm, and is free from scratches or pit damage.

[0045] Compared with the prior art, the technical effects of the present invention are as follows:

[0046] 1) By controlling the deformation direction and pressure of the membrane medium based on air pressure regulation, the contact pressure distribution between the membrane medium and optical elements can be controlled to obtain nanoscale surface accuracy.

[0047] 2) The film medium (metal sheets / foils such as nickel, ruthenium, and copper) is a soft material with a hardness lower than that of the component to be polished (such as fused silica, silicon carbide, etc.), and will not cause scratches or pits on the component surface. This ensures that the processed optical component has a complete surface and lattice structure.

[0048] 3) The film medium (metal sheets / foils such as nickel, ruthenium and copper) acts as a catalyst. Through the interaction between catalyst atoms and element atoms, an ultra-smooth surface at the picometer level is obtained for optical elements, overcoming the form of precious metal coating in the existing technology and greatly reducing the processing cost.

[0049] 4) By controlling the pressure (direction and magnitude) of the membrane medium and the processing parameters (load pressure, rotation speed, polishing time, and type and concentration of catalyst), a single device can be used to achieve both shaping and polishing as well as ultra-smooth treatment. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the membrane medium shaping and ultra-smooth processing device with air pressure regulation according to the present invention.

[0051] Figure 2 This is a schematic diagram and a partial enlarged view of the air pressure-controlled membrane medium shaping and ultra-smooth processing device of the present invention.

[0052] Figure 3 This is a schematic diagram of the undulating deformation of the membrane medium under the action of a pneumatic suction cup in this invention.

[0053] In the diagram: 1-Polishing platform, 11-Platform drive motor, 2-Pneumatic suction cup, 21-Micropore, 3-Membrane medium, 31-Membrane medium protrusion, 32-Membrane medium depression, 4-Component to be polished, 5-Buffer medium, 6-Base, 61-Base drive motor, 7-Polishing solution Detailed Implementation

[0054] The present invention will be further described below with reference to embodiments, but these embodiments should not be construed as limiting the scope of the invention.

[0055] See Figure 1 , Figure 1 This is a schematic diagram of the pressure-controlled membrane dielectric shaping and ultra-smooth processing apparatus of the present invention, as shown in the figure, including:

[0056] Lower driver module:

[0057] Polishing platform 1: Driven by a motor to rotate (50-80 rpm), it carries the pneumatic suction cup 2 and the membrane medium 3.

[0058] Pneumatic suction cup 2: The surface is divided into 3 to 10 independent zones, each zone is equipped with micropores 21 (diameter 100μm to 1mm), and the air pressure of each zone (0.01 to 0.1MPa) is regulated by a vacuum generator, flow meter and reversing valve to achieve air suction or blowing.

[0059] Membrane medium 3: High-purity (≥99.9%) transition metal foil (such as nickel, ruthenium, copper), with a thickness of 0.01 to 0.05 mm, which has both flexibility and catalytic activity.

[0060] Upper driver module:

[0061] Base 6 and buffer medium 5: Fix the element to be polished 4 (such as fused silica), and uniformly transmit the load pressure (10~40kPa) through buffer materials such as polyurethane.

[0062] Polishing solution 7: Deionized water (resistivity ≥15MΩ·cm) with added oxidant (such as H2O) or pH adjuster (oxalic acid, ammonia, etc.).

[0063] This embodiment uses diameter Using 5mm thick fused silica elements as the processing target, a method for film dielectric shaping and ultra-smooth processing based on gas pressure control is proposed. This method achieves high-precision, damage-free ultra-smooth surface processing by controlling the film dielectric morphology through zoned gas pressure control and combining it with specific process parameters. The specific implementation steps are as follows:

[0064] Phase 1: Preparation of Processing Equipment and Materials

[0065] Polishing platform: Select an aluminum polishing platform with a diameter of 200mm and a surface flatness of less than 20μm to ensure stability during the processing.

[0066] Pneumatic suction cup: The pneumatic suction cup is made of silicon carbide with a surface flatness of 10μm. The surface of the pneumatic suction cup is divided into 5 sections, with the radii of each section being R1, R2, ..., R5. Each section has micropores with a diameter of 100μm, and each section contains 300 to 400 micropores for precise air pressure control.

[0067] Drive system: Both the upper and lower drive modules use servo motors to achieve precise speed and position control.

[0068] The component to be polished is made of fused silica.

[0069] Buffer medium: Polyurethane material is selected to protect the surface of the component during polishing and prevent scratches.

[0070] Membrane medium: Nickel foil with a diameter of 200 mm, a thickness of 20 μm, and a purity of ≥99.99%.

[0071] Polishing solution: Deionized water with a resistivity of 15 MΩ·cm is used.

[0072] Phase Two: Shaping and Polishing

[0073] Assembly: First, fix the pneumatic chuck to the polishing platform, then fix a complete sheet of nickel foil as a dielectric film onto the pneumatic chuck. Fix the fused silica element to be shaped and polished onto the lower surface of the buffer medium, and apply a load pressure of 25 kPa to the top surface of the optical element through a load device.

[0074] Polishing solution addition: Add polishing solution dropwise to the interface between the membrane medium and the element at a rate of 5-10 ml / min.

[0075] Start polishing: Set the component rotation speed to 65 rpm and the polishing disc rotation speed to 60 rpm. The polishing platform and the fused silica component rotate counterclockwise.

[0076] Air pressure control: Based on the surface shape error data between the input and designed surface shapes of the component, initial pressure combinations for each zone are generated. Through microporous air pressure control, the membrane medium exhibits a morphology conjugate to the error distribution. Specifically, using a pneumatic suction cup auxiliary device, zones 1, 3, and 4 of the suction cup are set to suction at a pressure of 0.03 MPa, while zones 2 and 5 are set to blowing at a pressure of 0.025 MPa. The component surface shape is checked and the air pressure is adjusted every 10 minutes, prioritizing the correction of low-frequency surface shape errors before transitioning to high-frequency error processing (ultra-smoothing).

[0077] Phase 3: Ultra-smooth processing

[0078] Reassembly: Reattach the pneumatic chuck to the polishing platform, and then attach a complete nickel film dielectric sheet to the pneumatic chuck. Fix the fused silica element to be shaped and polished to the lower surface of the buffer medium, and apply a load pressure of 15 kPa to the top surface of the optical element.

[0079] Polishing solution addition: Add polishing solution dropwise to the interface between the membrane medium and the element at a rate of 1-5 ml / min.

[0080] Start polishing: Start the polishing machine. The component speed is 30 rpm and the polishing disc speed is 25 rpm. The polishing platform rotates counterclockwise around the center. While the molten quartz component is rotating, it also reciprocates along the radial direction of the pneumatic suction cup at an eccentric distance of 10-25 mm to achieve ultra-smooth processing.

[0081] Air pressure maintenance: The air pressure at each micro-hole in different radius zones on the surface of the pneumatic suction cup is kept in the same direction and at a magnitude of 0.015MPa, and an ultra-smooth surface is achieved.

[0082] Phase 4: Detection and Evaluation

[0083] After polishing for a certain period of time, the fused silica element is removed and cleaned. The surface shape and roughness are then tested using a laser interferometer and an atomic force microscope, respectively. When the root mean square value of the fused silica element's surface shape is better than 10 nm, and the root mean square value of the fused silica element's roughness is better than 0.1 nm, the high-precision ultra-smooth processing is completed.

[0084] Laser interferometer testing results show that within a φ30mm region, the root mean square value of the fused silica element surface area is 9.3nm. Atomic force microscopy testing results show a surface area of ​​1×1μm. 2 Within the testing range, the root mean square value of the surface roughness of the fused silica element was 0.066 nm. Since the hardness of nickel is less than that of fused silica, it will not produce scratches on the surface of the fused silica element, thus obtaining a high-precision, ultra-smooth, and damage-free fused silica surface.

[0085] This embodiment solves the contradiction between precision, damage, and cost in optical component processing by dynamically controlling the deformation of the film medium through air pressure and catalytic polishing, providing an innovative solution for high-end optical manufacturing.

[0086] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. This includes, but is not limited to, the material, shape, and size of the sample. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A gas pressure regulated film medium reshaping and ultra-smooth finishing apparatus, characterized by, The polishing device comprises a lower driving module, an upper driving module, an auxiliary device and a polishing solution supply system, wherein The lower driving module comprises, from bottom to top, in sequence: a platform driving motor (11) whose output shaft is rigidly connected to the center of a polishing platform (1) through a shaft coupling; the polishing platform (1) whose upper surface is fixedly connected to a pneumatic chuck (2) through bolts; The pneumatic suction cup (2) is an annular disc body, and a plurality of concentric circular ring partitions are arranged on the upper surface of the disc body. A plurality of micropores (21) are uniformly distributed in each ring partition. Each ring partition is connected to an auxiliary device through an independent air pipe. The surface of the pneumatic suction cup is divided into n ring partitions according to the radius, and n is 3-10. The radius of each ring partition is represented as R i (i=1,…,n). Micropores are arranged in the ring partition of each ring partition. The diameter of the micropores ranges from 100 μm to 1 mm. The number of micropores in each ring partition is not more than (R i 2 - R i-1 2 ) / 2, (i=2,…,n). a film medium (3) which is flatly adhered to the upper surface of the pneumatic chuck (2) through negative pressure adsorption; the film medium is a layer of metal sheet / foil adhered to the surface of the pneumatic chuck, the metal is a transition metal of VIIB, VIII and IB group, and the purity is not less than 99.9%; the thickness of the film medium is 0.01-0.05 mm; The upper driving module comprises, from top to bottom, in sequence: a base driving motor (61) whose output shaft is coaxially connected to the center of the top of a base (6) through a flange; the base (6) which is a cylinder and whose bottom is fixedly connected to a buffer medium (5) through adhesion; the buffer medium (5) whose lower surface is fixedly connected to a component to be polished (4) through vacuum adsorption or adhesion; The auxiliary device comprises: a vacuum generator which is connected to the air inlet manifold of the pneumatic chuck (2) through a main air pipe; a gas flow meter which is arranged on each sub-branch air pipe and used for controlling air pressure; a reversing valve which is arranged at the end of each sub-branch air pipe and used for switching between air suction and air blowing modes; The polishing solution supply system has a drop nozzle which is located above the contact interface between the film medium (3) and the component to be polished (4); Wherein, the air pressure and airflow direction of each sub-zone of the pneumatic chuck (2) are adjusted by the auxiliary device, so that the deformation amount δ of the film medium and the surface shape error of the component are conjugately matched, and the formula of the deformation amount δ of the film medium is as follows: where ΔΡ is the pressure difference across the membrane medium, R is the pore radius, E is the modulus of elasticity of the membrane medium material, v is the Poisson's ratio of the membrane medium material, and D is the bending stiffness of the membrane medium.

2. The pneumatic-regulated, film-mediated, figure- correcting, ultra-smooth and finishing apparatus of claim 1, wherein, The polishing platform is used for bearing the pneumatic chuck and the film medium, and is made of stainless steel or aluminum, and the flatness is ≤50 μm; the surface flatness of the pneumatic chuck is ≤10 μm, and the material of the pneumatic chuck is alumina or silicon carbide.

3. The pneumatic-regulated film medium shaping and ultra-smooth finishing device of claim 1, wherein, The polishing solution comprises a polishing solvent, and the polishing solvent is deionized water with a resistivity of ≥15 MΩ·cm.

4. The air pressure regulated film medium shaping and ultra-smooth finishing device of claim 1, wherein, In the upper driving module, the material of the base is stainless steel or aluminum, the upper part of the base is fixedly and coaxially connected to the driving motor, and the buffer medium is fixedly connected to the lower surface of the base, and the buffer medium is polyurethane, damping cloth, non-woven fabric or sponge material.

5. A method for profile modification and super-smooth processing of a film medium based on air pressure regulation of the processing device according to any one of claims 1-4, characterized in that, It comprises: a shaping and polishing stage: fixing the component to be polished on the lower surface of the buffer medium and applying a load pressure of 15-40 kPa; dropping the polishing solution on the contact interface between the component to be polished and the film medium at a dropping rate of 1-10 ml / min; starting the platform driving motor (11) and the base driving motor (61) and controlling the rotating speed of the polishing platform (1) and the component to be polished (4) to be 50-80 rpm; adjusting the air pressure and airflow direction of each sub-zone of the pneumatic chuck (2) by the auxiliary device, so that the deformation amount δ of the film medium and the surface shape error of the component are conjugately matched, and the formula of the deformation amount δ of the film medium is as follows: where ΔΡ is the pressure difference across the membrane medium, R is the pore radius, E is the modulus of elasticity of the membrane medium material, v is the Poisson's ratio of the membrane medium material, and D is the bending stiffness of the membrane medium. dynamically adjusting the air pressure and continuously shaping and polishing until the root mean square value of the surface shape error of the component is ≤10 nm; an ultra-smooth processing stage: reducing the load pressure to 10-20 kPa and adjusting the dropping rate of the polishing solution to 1-5 ml / min; The rotation speed of the polishing platform (1) and the to-be-polished element (4) is controlled to be 10-30 rpm, and the element is subjected to 10-25 mm eccentric reciprocating motion along the radial direction of the pneumatic chuck; All sub-zones of the pneumatic chuck are set to uniform suction, and the air pressure is 0.01-0.02 MPa, and the atomic-level material removal is realized by the catalytic action of the film medium (3). The polishing is continuously performed until the surface roughness of the element is less than or equal to 0.1 nm.

6. The gas pressure regulated, film media shaping and ultra- smoothing process of claim 5, wherein, In the profiled polishing stage, the sub-zone air pressure of the pneumatic chuck (2) is controlled as follows: the sub-zone corresponding to the concave area of the element surface profile is set to suction at 0.015-0.03 MPa, and the sub-zone corresponding to the convex area of the element surface profile is set to blowing at 0.03-0.05 MPa.

7. The gas pressure regulated, film media shaping and ultra- smoothing process of claim 5, wherein, When the film medium (3) is a nickel foil, 5 wt% hydrogen peroxide is added to the polishing solution (7), and the pH value is adjusted to 3-5.

8. An optical element, characterized by, The element is processed by the method of any one of claims 5-7, and has a surface profile root mean square value of less than or equal to 10 nm, a surface roughness root mean square value of less than or equal to 0.1 nm, and no scratch or pit damage.

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