Vertical self-adaptive zero-gravity floating machining method and device

Abstract

According to the vertical self-adaptive zero-gravity floating machining method and device, the output force of an air bearing air cylinder is adjusted by adjusting air pressure, upward acting force is provided for a connecting support, friction-free vertical guiding is achieved through an air floating module, and the effect of balancing the gravity of the device in the vertical direction is achieved; and zero-gravity floating is realized. The workpiece is horizontally placed and machined, the workpiece with the large size and mass can be allowed to be polished, and more flexible machining is achieved in combination with movement of the polishing mechanical arm. By adjusting the air pressure, the liquid film thickness and the fluid dynamic pressure can be indirectly adjusted, the material removal rate is adjusted, the system cost is reduced, and meanwhile polishing of sub-nanometer level surface roughness is achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of ultra-precision polishing equipment, and particularly relates to a vertical adaptive zero-gravity floating machining method and device. Background Technology

[0002] With the rapid development of fields such as optical engineering, aerospace, and semiconductor manufacturing, the requirements for the surface processing accuracy of workpieces are becoming increasingly stringent. This not only necessitates achieving sub-nanometer level surface roughness but also requires avoiding defects such as scratches and subsurface damage during processing. Existing polishing technologies are mainly divided into two categories: contact polishing and non-contact polishing.

[0003] Contact polishing (such as chemical mechanical polishing and pneumatic polishing) removes material through direct or flexible contact between the tool and the workpiece. However, it is prone to surface scratches due to abrasive extrusion and tool wear. Furthermore, clearance control relies on machine tool rigidity, making it unsuitable for machining complex curved surfaces or ultra-thin workpieces. Non-contact polishing (such as ion beam polishing and magnetorheological polishing), while avoiding direct contact and achieving sub-nanometer surface roughness, is limited by foreign technological monopolies, high equipment costs, and low processing efficiency, making it difficult to meet mass production demands. Additionally, existing devices that adapt clearance adjustment through horizontal floating significantly limit the size and mass of workpieces that can be processed. Therefore, there is an urgent need for a processing equipment that can meet sub-nanometer surface roughness requirements, is suitable for larger and heavier workpieces, and combines stability with low cost. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention proposes a vertical adaptive zero-gravity floating processing method and device.

[0005] This invention proposes a vertical adaptive zero-gravity floating machining method and device: by adjusting the air pressure to regulate the output force of the air bearing cylinder, an upward force is provided to the connecting bracket. The air-floating module achieves frictionless vertical guidance, balancing the device's weight in the vertical direction and realizing zero-gravity floating. The workpiece is placed horizontally for machining, allowing for the polishing of larger workpieces with greater volume and mass. Combined with the movement of the polishing robotic arm, more flexible machining is achieved. During machining, a water tank contains polishing fluid, and both the tool and the workpiece are immersed in the fluid. Increasing the air pressure increases the output force of the air bearing cylinder, causing an upward tendency for the entire assembly to press the tool firmly against the workpiece surface. The spindle drives the tool to rotate at high speed. Due to the hydrodynamic pressure, the device experiences a downward force, causing the workpiece to move away from the tool. As the hydrodynamic pressure decreases, the device moves upward under the output force of the cylinder until the sum of the device's gravity and the hydrodynamic pressure equals the cylinder output force, reaching a state of equilibrium. Ultimately, a stable liquid film of stable thickness forms between the tool and the workpiece. The zero-gravity floating device achieves adaptive gap adjustment, eliminating the dependence of the polishing robot arm's vertical positioning accuracy on the polishing process. Polishing particles in the polishing fluid contact the workpiece surface, and under the combined action of chemical reaction and physical shearing, atomic-level material removal is achieved from the workpiece surface. By adjusting the air pressure, the liquid film thickness and hydrodynamic pressure can be indirectly adjusted, thereby regulating the material removal rate, reducing system costs, and achieving sub-nanometer level surface roughness polishing.

[0006] A vertical adaptive zero-gravity floating machining device comprises a fixed platform, a robotic arm mounting platform, a polishing robotic arm, a spindle, a tool, a base, an air bearing cylinder, a connecting bracket, a water tank, a worktable, a workpiece, an air flotation module, and a connecting plate.

[0007] The fixed platform is set horizontally, and the robotic arm mounting platform is fixed to one side of the upper surface of the fixed platform by bolts. The polishing robotic arm is fixed to the top of the robotic arm mounting platform by bolts. The main shaft is detachably connected to the end of the polishing robotic arm by a clamp, and the tool is fixed to the lower end of the main shaft.

[0008] The base is vertically mounted on the other side of the upper surface of the fixed platform. The air flotation module is fixed to the base by bolts. The connecting plate is vertically fixed to the air flotation module. The short side of the connecting bracket is fixed to the connecting plate. The air bearing cylinder is vertically fixed to the side of the base. The top of the cylinder rod is fixed to the connecting bracket. The water cylinder is placed above the connecting bracket. The workpiece is fixed on the workbench. The workbench is placed inside the water cylinder.

[0009] During processing, the water tank contains polishing fluid, and the workpiece is immersed and fixed on the worktable inside the tank. The entire assembly consisting of the water tank, polishing fluid, worktable, and workpiece is subjected to downward gravity, exerting a vertically downward force on the connecting bracket. The connecting bracket is connected to the air flotation module via a connecting plate, which provides frictionless vertical guidance for the connecting components. The outer wall of the air bearing cylinder is fixed by a base, and the cylinder rod is connected to the cylinder via a ball joint. The output end of the cylinder rod is fixed to the connecting bracket, achieving near-frictionless force output. By adjusting the air pressure, the output force of the air bearing cylinder can be adjusted, ensuring that the entire assembly consisting of the water tank, polishing fluid, worktable, and workpiece reaches a state of force balance in the vertical direction, keeping the assembly in a zero-gravity state within the allowable stroke.

[0010] During the processing, the polishing robot arm moves the spindle above the workpiece, causing the tool axis to be at an angle to the processing plane. Both the tool and the workpiece are immersed in the polishing fluid. By adjusting the cylinder pressure, the entire system is brought to a state of zero gravity. Increasing the cylinder pressure further increases the cylinder output force, causing the system to move upwards and press the tool firmly against the workpiece surface. After the spindle is powered on, it drives the tool to rotate at high speed, simultaneously rotating the polishing fluid in the tank. The hydrodynamic pressure is transmitted through the workpiece, worktable, and tank to the air bearing cylinder and air flotation module, subjecting the system to a downward vertical force. As the distance between the tool and workpiece increases, the hydrodynamic pressure decreases, causing the system to move upwards again until the sum of the hydrodynamic pressure and the system's weight equals the cylinder output force, reaching a state of equilibrium. A stable liquid film exists between the tool and the workpiece. When the polishing robot arm makes a vertical positioning error, the air bearing cylinder and air flotation module work together to compensate for the vertical positioning error, stabilizing the liquid film thickness and achieving a self-adaptive gap effect.

[0011] The output force of the air bearing cylinder is determined by the air pressure; adjusting the air pressure changes the output force. Because the air flotation module provides frictionless vertical guidance, the output force of the air bearing cylinder balances the overall weight of the water tank, internal polishing fluid, worktable, workpiece, connecting bracket, etc., as well as the hydrodynamic pressure during processing. By adjusting the air pressure, the hydrodynamic pressure and liquid film thickness during processing can be indirectly adjusted.

[0012] The polishing robot arm, along with the robot arm mounting platform and the zero-gravity floating device, is mounted on a unified fixed platform. During the processing, the position and posture of the tool can be changed by controlling the polishing robot arm. The vertical positioning error is compensated by the air bearing cylinder and the air float module, enabling flexible changes in the processing path. The gap-adaptive structure makes the positioning accuracy of non-contact processing no longer dependent on the accuracy of the polishing robot arm, and enables the surface roughness of the processed workpiece to reach the sub-nanometer level.

[0013] The device that provides vertical upward support for the entire assembly consisting of the water tank, internal polishing fluid, worktable, workpiece, connecting bracket, etc., is not limited to air bearing cylinders, but includes various devices that can provide adjustable output force. The force supply methods include providing vertical upward thrust or vertical upward tension. By adjusting the output force of the power supply device, the entire assembly consisting of the water tank, internal polishing fluid, worktable, workpiece, connecting bracket, etc., can be placed in a zero-gravity state, achieving floating machining.

[0014] By combining a polishing robotic arm with a zero-gravity floating device, sub-nanometer polishing of flat surfaces and various curved surfaces can be achieved.

[0015] The clamping tools are not limited to robotic arms, but include various multi-axis displacement platforms. The beneficial effects of this invention are:

[0016] Compared with existing non-contact polishing devices, the biggest advantages of this invention are: First, by using the output force of the air bearing cylinder and the vertical guidance of the air-floating module, the gravity balance of the processed parts is achieved, resulting in a zero-gravity floating effect. This allows for horizontal placement of the workpiece during processing, enabling the polishing of workpieces with larger volumes and masses. Combined with the movement of the polishing robot arm, this improves the flexibility of the processing path. Second, by adjusting the air pressure to regulate the output force of the air bearing cylinder, the hydrodynamic pressure and liquid film thickness can be adjusted. The zero-gravity floating device achieves adaptive clearance between the workpiece and the tool in the vertical direction, eliminating the dependence of the polishing process on the vertical positioning accuracy of the polishing robot arm. This reduces system costs while achieving sub-nanometer level surface roughness. Attached Figure Description

[0017] Figure 1 This is a structural diagram of a vertical adaptive zero-gravity floating machining device.

[0018] Figure 2 This is a schematic diagram of a vertical adaptive zero-gravity floating machining process. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0020] like Figure 1 , Figure 2 As shown, the vertical adaptive zero-gravity floating processing device of the present invention comprises a fixed platform 101, a robotic arm mounting platform 102, a polishing robotic arm 103, a spindle 104, a tool 105, a base 106, an air bearing cylinder 107, a connecting bracket 108, a water tank 109, a worktable 110, a workpiece 111, an air flotation module 112, and a connecting plate 113;

[0021] The fixed platform is set horizontally, and the robotic arm mounting platform is fixed to one side of the upper surface of the fixed platform by bolts. The polishing robotic arm is fixed to the top of the robotic arm mounting platform by bolts. The main shaft is detachably connected to the end of the polishing robotic arm by a clamp, and the tool is fixed to the lower end of the main shaft.

[0022] The base is vertically mounted on the other side of the upper surface of the fixed platform. The air flotation module is fixed to the base by bolts. The connecting plate is vertically fixed to the air flotation module. The short side of the connecting bracket is fixed to the connecting plate. The air bearing cylinder is vertically fixed to the side of the base. The top of the cylinder rod is fixed to the connecting bracket. The water cylinder is placed above the connecting bracket. The workpiece is fixed on the workbench. The workbench is placed inside the water cylinder.

[0023] like Figure 2 As shown, during the processing, the water tank contains polishing fluid, and the workpiece is immersed and fixed on the worktable inside the water tank. The entire assembly consisting of the water tank, the internal polishing fluid, the worktable, and the workpiece is subjected to downward gravity, exerting a vertically downward force on the connecting bracket. The connecting bracket is connected to the air flotation module via a connecting plate, and the air flotation module provides frictionless vertical guidance for the connecting components. The outer wall of the air bearing cylinder is fixed by a base, and the cylinder rod is connected to the cylinder via a ball joint. The output end of the cylinder rod is fixed to the connecting bracket, achieving near-frictionless force output. By adjusting the air pressure, the output force of the cylinder can be adjusted, so that the entire assembly consisting of the water tank, the internal polishing fluid, the worktable, and the workpiece reaches a force balance state in the vertical direction, keeping the assembly in a zero-gravity state within the allowable stroke.

[0024] During the processing, the polishing robot arm moves the spindle above the workpiece, causing the tool axis to be at an angle to the processing plane. Both the tool and the workpiece are immersed in the polishing fluid. By adjusting the cylinder pressure, the entire system is brought to a state of zero gravity. Increasing the cylinder pressure further increases the cylinder output force, causing the system to move upwards and press the tool firmly against the workpiece surface. After the spindle is powered on, it drives the tool to rotate at high speed, simultaneously rotating the polishing fluid in the tank. The hydrodynamic pressure is transmitted through the workpiece, worktable, and tank to the air bearing cylinder and air flotation module, subjecting the system to a downward vertical force. As the distance between the tool and workpiece increases, the hydrodynamic pressure decreases, causing the system to move upwards again until the sum of the hydrodynamic pressure and the system's weight equals the cylinder output force, reaching a state of equilibrium. A stable liquid film exists between the tool and the workpiece. When the polishing robot arm makes a vertical positioning error, the air bearing cylinder and air flotation module work together to compensate for the vertical positioning error, stabilizing the liquid film thickness and achieving a self-adaptive gap effect.

[0025] The output force of the air bearing cylinder is determined by the air pressure; adjusting the air pressure changes the output force. Because the air flotation module provides frictionless vertical guidance, the output force of the air bearing cylinder balances the overall weight of the water tank, internal polishing fluid, worktable, workpiece, connecting bracket, etc., as well as the hydrodynamic pressure during processing. By adjusting the air pressure, the hydrodynamic pressure and liquid film thickness during processing can be indirectly adjusted.

[0026] The polishing robot arm, along with the robot arm mounting platform and the zero-gravity floating device, is mounted on a unified fixed platform. During the processing, the position and posture of the tool can be changed by controlling the polishing robot arm. The vertical positioning error is compensated by the air bearing cylinder and the air float module, enabling flexible changes in the processing path. The gap-adaptive structure makes the positioning accuracy of non-contact processing no longer dependent on the accuracy of the polishing robot arm, and enables the surface roughness of the processed workpiece to reach the sub-nanometer level.

[0027] The device that provides vertical upward support for the entire assembly consisting of the water tank, internal polishing fluid, worktable, workpiece, connecting bracket, etc., is not limited to air bearing cylinders, but includes various devices that can provide adjustable output force. The force supply methods include providing vertical upward thrust or vertical upward tension. By adjusting the output force of the power supply device, the entire assembly consisting of the water tank, internal polishing fluid, worktable, workpiece, connecting bracket, etc., can be placed in a zero-gravity state, achieving floating machining.

[0028] By combining a polishing robotic arm with a zero-gravity floating device, sub-nanometer polishing of flat surfaces and various curved surfaces can be achieved.

[0029] Clamping tools are not limited to robotic arms, but include various multi-axis displacement platforms.

[0030] Matters not covered in this invention are common knowledge.

[0031] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A vertical self-adaptive zero-gravity floating processing device, comprising a fixed platform (101), a mechanical arm mounting platform (102), a polishing mechanical arm (103), a main shaft (104), a tool (105), a base (106), an air bearing cylinder (107), a connecting bracket (108), a water cylinder (109), a workbench (110), a workpiece (111), an air floating module (112), and a connecting plate (113); the fixed platform is horizontally arranged, the mechanical arm mounting platform is fixed on one side of the upper surface of the fixed platform by bolts, the polishing mechanical arm is fixed on the top of the mechanical arm mounting platform by bolts, the main shaft is detachably connected with the polishing mechanical arm at the end by a clamp, and the tool is fixed at the lower end of the main shaft; characterized in that: the base is fixedly arranged on the other side of the upper surface of the platform, the air floating module is fixed on the base, the connecting bracket is fixed on the air floating module through the connecting plate, the air bearing cylinder is vertically fixed on the side surface of the base, the cylinder rod is fixed at the top end of the connecting bracket, the water cylinder is arranged above the connecting bracket, the workpiece is fixed on the workbench, and the workbench is arranged in the water cylinder. The polishing mechanical arm drives the main shaft above the workpiece, so that the tool shaft is inclined to the processing plane for processing.

2. A vertical self-adapting zero-gravity floating processing device according to claim 1, characterized in that: The mechanical arm can be replaced by various multi-axis displacement platforms.

3. A vertical self-adapting zero-gravity floating processing device according to claim 1, characterized in that:

4. The vertical self-adaptive zero-gravity floating processing method according to claim 1, characterized in that: During processing, the water cylinder contains polishing liquid, and the workpiece is fixedly arranged on the workbench in the water cylinder; the whole composed of the water cylinder, the polishing liquid in the water cylinder, the workbench, and the workpiece exerts a vertical downward force on the connecting bracket; the connecting bracket is connected with the air floating module through the connecting plate, the air floating module provides a vertical guiding function for the connecting part without friction; the outer wall of the air bearing cylinder is fixed through the base, the cylinder rod is connected with the cylinder through a spherical hinge, the output end of the cylinder rod is fixed with the connecting bracket, and the force output is realized close to zero friction; the output force of the air bearing cylinder is adjusted by adjusting the air pressure, so that the whole composed of the water cylinder, the polishing liquid in the water cylinder, the workbench, and the workpiece reaches a force balance state in the vertical direction, and the whole is in a zero-gravity state within the allowable stroke. The output force of the air bearing cylinder is adjusted by adjusting the air pressure, so that the whole composed of the water cylinder, the polishing liquid in the water cylinder, the workbench, and the workpiece reaches a force balance state in the vertical direction, and the whole is in a zero-gravity state within the allowable stroke, specifically:

5. A vertical self-adapting zero-gravity floatation machining method according to claim 4, characterized in that: ​ By adjusting the air bearing cylinder air pressure, the whole is in zero gravity state, continue to increase the cylinder air pressure, increase the air bearing cylinder output force, make the whole has the tendency of upward movement, make the tool press in the workpiece surface; After the spindle is powered on, it drives the tool to rotate at high speed, at the same time drives the polishing liquid in the water cylinder to rotate, the fluid dynamic pressure is transmitted to the air bearing cylinder and the air floating module through the workpiece, the workbench and the water cylinder, so that the whole is subjected to the vertical downward force, with the increase of the distance between the tool and the workpiece, the fluid dynamic pressure decreases, the whole will move upward again, until the sum of the fluid dynamic pressure and the gravity of the whole is equal to the output force of the cylinder, the balance state is reached, there is a layer of stable liquid film between the tool and the workpiece, when the positioning error of the polishing mechanical arm in the vertical direction appears, the air bearing cylinder and the air floating module jointly compensate the positioning error in the vertical direction, so that the liquid film thickness is stable, the effect of gap self-adaptation is achieved.

6. A vertical self-adapting zero-gravity floating machining method according to claim 4 or 5, characterized in that: By combining the polishing mechanical arm with the zero gravity floating device, the sub-nanometer level polishing of plane and various curved surface types is realized.

7. A vertical self-adapting zero-gravity floating machining method according to claim 4 or 5, characterized in that: The mechanical arm can be replaced by various multi-axis displacement platforms.

Images