Precise polishing grinding head capable of being partitioned and deformed controllably

Abstract

The invention belongs to the technical field of precision machining equipment, and discloses a partitioned and deformation-controllable precision polishing grinding head which comprises a partitioned base, a positioning block is arranged in the center of the lower portion of the partitioned base, at least one connecting rod assembly is arranged above the partitioned base, and the top end of each connecting rod assembly is connected with a curvature adjusting head. A flexible polishing head is arranged above the curvature adjusting head, a protective shell is arranged on the outer side of the connecting rod assembly, the flexible polishing head and the protective shell are connected through a grinding head frame, and the whole device is provided with a drive circuit. According to the precise polishing grinding head capable of being partitioned and deformed controllably, through the partitioned base and the independent shape memory alloy driver, the curvature radiuses of the center and the edge of the flexible polishing head are controlled, the edge pressure is optimized, stable contact rigidity and uniform pressure distribution are brought, and finer surface shape control is achieved; the shape memory alloy driver is a solid-state element and is matched with the transverse amplification connecting rod, and needed driving force and displacement can be achieved in a relatively compact space.

Description

Technical Field

[0001] The present invention relates to the technical field of precision machining equipment, and in particular to a precision polishing grinding head with partitioned and controllable deformation. Background Art

[0002] With the rapid development of modern optical manufacturing technology, optical components or mechanical parts are increasingly widely used in fields such as aerospace, national defense, astronomy, and laser systems. Major national projects such as large astronomical telescopes, high-energy laser systems, and advanced military optical systems have put forward strict requirements for the machining accuracy and surface quality of optical components or mechanical parts.

[0003] Polishing, as the core process in the precision machining of optical components and mechanical parts, directly affects the surface shape accuracy, surface roughness, and overall performance of the components. In the machining of optical components, polishing determines the imaging quality and stability of the optical system; while in the machining of mechanical parts, polishing affects the wear resistance, corrosion resistance, and assembly accuracy of the parts. Among many polishing techniques, computer-controlled small grinding head polishing has become the mainstream method in modern ultra-precision manufacturing due to its high controllability, flexibility, and process repeatability. During the polishing process, the radius of curvature of the grinding head is one of the key parameters affecting the polishing result, directly affecting the surface shape accuracy, surface roughness, and material removal efficiency of the machining surface. When a grinding head with a fixed radius of curvature is used to machine the edge of a workpiece, due to the increase in the contact line speed gradient, edge over-removal is likely to occur. In addition, curvature mismatch will reduce the contact stiffness and is prone to causing high-frequency chatter, resulting in the deterioration of surface waviness. These problems not only affect the imaging quality of optical components but also the surface quality and service life of mechanical parts. In view of this, developing a polishing grinding head with partitioned and controllable deformation has become an ideal solution to solve the above problems. Summary of the Invention

[0004] The object of the present invention is to provide a precision polishing grinding head with partitioned and controllable deformation. Through a partitioned base and an independent shape memory alloy actuator array, the radius of curvature of the center and edge of the flexible polishing head can be independently controlled, optimizing the edge pressure distribution, bringing more stable contact stiffness and more uniform pressure distribution, suppressing or compensating for problems such as edge over-removal or under-removal caused by factors such as line speed changes, improving the surface shape accuracy of the workpiece edge, and achieving more refined and localized surface shape control.

[0005] To achieve the above-mentioned objectives, the present invention provides a precision polishing grinding head with partitionable and controllable deformation, comprising a partition base, a positioning block is arranged in the center below the partition base, and at least one group of connecting rod assemblies are arranged above the partition base, the connecting rod assembly comprises a shape memory alloy driver, a curvature adjustment head is connected to the top of the connecting rod assembly, a flexible polishing head is arranged above the curvature adjustment head, a protective shell is arranged on the outside of the connecting rod assembly, the flexible polishing head and the protective shell are connected through a grinding head frame, and the device as a whole is provided with a driving circuit, and the driving circuit controls the shape memory alloy driver to realize partitioned and controllable deformation of the flexible polishing head.

[0006] Preferably, the partition base is provided with at least one partition unit, the partition units are evenly distributed on the surface of the partition base, the connecting rod assembly corresponds to the number and position of the partition units, and the connecting rod assembly is used to independently control the partitions of the flexible polishing head.

[0007] Preferably, the connecting rod assembly includes a base, which is connected to the partition base by bolts, a fork rod and a driver support rod are arranged in parallel above the base, the top of the driver support rod is connected to the shape memory alloy driver, the shape memory alloy driver and the fork rod are movably connected through a transverse amplification connecting rod, the tail end of the transverse amplification connecting rod is hinged with a first connecting rod, the first connecting rod is hinged with a second connecting rod, the second connecting rod is connected to the curvature adjustment head, and the second connecting rod is used to transmit the displacement of the shape memory alloy driver to the curvature adjustment head.

[0008] Preferably, the shape memory alloy driver is connected to the head end of the transverse amplification link, and the fork rod is connected to the middle section of the transverse amplification link.

[0009] Preferably, the outer contour of the curvature adjusting head is hemispherical, and the curvature adjusting head is provided with a gap, and the gap structure is used to generate controllable deformation when the curvature adjusting head is subjected to force.

[0010] Preferably, the flexible polishing head is in direct contact with the curvature adjusting head, and the flexible polishing head adjusts the curvature radius of the working surface through the curvature adjusting head.

[0011] Preferably, the driving circuit includes a main control system, which receives signal inputs from a processing path storage unit and a workpiece morphology measurement module, and inputs control quantities to a shape memory alloy driver control module. The shape memory alloy driver control module drives the connecting rod assembly to move and amplifies the displacement effect on the curvature adjustment head, and the curvature adjustment head controls the flexible polishing head to produce deformation and is used for workpiece processing. The driving circuit is provided with a power supply module.

[0012] Therefore, the present invention adopts the above-mentioned precision polishing head with partitionable and controllable deformation, and has the following beneficial effects:

[0013] 1) It realizes the "partitionable and controllable" deformation of the curvature of the polishing head: When the traditional fixed-curvature polishing head polishes complex curved surfaces, especially in the edge area, there is a problem of curvature mismatch, resulting in uneven contact stress, and it is easy to produce defects such as excessive edge removal, medium and high-frequency surface errors, and scratches; Some existing deformable polishing heads can only achieve unified adjustment of the overall curvature and cannot specifically solve the different polishing requirements in the central and edge areas.

[0014] Through flexible deformation and curvature adjustment, the present invention can match the local curvature of the workpiece in real time and significantly improve the contact state; Through the partitioned base and the independent shape memory alloy actuator array, the curvature radii of the center and edge of the flexible polishing head can be independently controlled, the edge pressure distribution can be optimized, bringing more stable contact stiffness and more uniform pressure distribution, suppressing or compensating for problems such as excessive or insufficient edge removal caused by factors such as line speed change, improving the surface shape accuracy of the workpiece edge, and realizing more refined and more localized surface shape control.

[0015] 2) It adopts solid-state drive and has a relatively compact structure: The shape memory alloy actuator is a solid-state drive element. Cooperating with the lateral amplification connecting rod, it can achieve the required driving force and displacement in a relatively compact space and is easy to be integrated into existing polishing equipment or robot systems.

[0016] 3) The present invention can be applied to the precision polishing of various complex curved surfaces, especially suitable for the processing of high-precision optical elements, aerospace components, precision medical devices and other fields, and can significantly improve the surface quality and surface shape accuracy.

[0017] Next, through the drawings and embodiments, the technical solutions of the present invention will be further described in detail. Description of the Drawings

[0018] Figure 1 is a schematic internal structure diagram of an embodiment of the precision polishing head with partitionable and controllable deformation of the present invention;

[0019] Figure 2 is an external view of an embodiment of the precision polishing head with partitionable and controllable deformation of the present invention;

[0020] Figure 3 is a structural diagram of the connecting rod assembly of an embodiment of the precision polishing head with partitionable and controllable deformation of the present invention;

[0021] Figure 4 is a structural diagram of the curvature adjustment head of an embodiment of the precision polishing head with partitionable and controllable deformation of the present invention;

[0022] Figure 5It is the schematic diagram of the curvature radius adjustment of the central area of an embodiment of the precision polishing grinding head with partition-controlled deformation of the present invention;

[0023] Figure 6 It is the schematic diagram of the curvature radius adjustment of the edge area of an embodiment of the precision polishing grinding head with partition-controlled deformation of the present invention;

[0024] Figure 7 It is the schematic diagram of the drive circuit control of an embodiment of the precision polishing grinding head with partition-controlled deformation of the present invention.

[0025] Reference numerals

[0026] 1. Partition base; 2. Positioning block; 3. Linkage assembly; 31. Base; 32. Bolt; 33. Fork rod; 34. Driver support rod; 35. Shape memory alloy driver; 36. Lateral amplification link; 37. First link; 38. Second link; 4. Curvature adjustment head; 5. Grinding head frame; 6. Flexible polishing head; 7. Protective shell. Detailed implementation manners

[0027] The technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0028] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0029] Embodiment 1

[0030] The present invention provides a precision polishing grinding head with partition-controlled deformation, as shown in Figure 1 and Figure 2As shown in the figure, it includes a partition base 1. A positioning block 2 is arranged in the center below the partition base 1. There is at least one set of connecting rod assemblies 3 above the partition base 1. The partition base 1 is provided with at least one partition unit, and the partition units are evenly distributed on the surface of the partition base 1. The number and positions of the connecting rod assemblies 3 correspond to those of the partition units. The partition base 1 can realize the zonal regulation of the curvature radius of the working surface of the polishing head. The partition base 1 includes a plurality of independent partition units, and each partition unit can independently adjust its corresponding curvature radius to adapt to the optical elements with complex curved surfaces. In this embodiment, the number of both the connecting rod assemblies 3 and the partition units of the polishing head is 6, and they are evenly distributed on the upper surface of the partition base 1.

[0031] The connecting rod assembly 3 is as Figure 3 shown in the figure, and it includes a base 31. The base 31 is connected to the partition base 1 by bolts 32. A fork rod 33 and a driver support rod 34 are arranged in parallel above the base 31. A shape memory alloy driver 35 is connected to the top of the driver support rod 34. The shape memory alloy driver 35 and the fork rod 33 are movably connected by a transverse magnification connecting rod 36. The tail end of the transverse magnification connecting rod 36 is hinged to a first connecting rod 37, and the first connecting rod 37 is hinged to a second connecting rod 38. The shape memory alloy driver 35 is connected to the head end of the transverse magnification connecting rod 36, and the fork rod 33 is connected to the middle section of the transverse magnification connecting rod 36. The shape memory alloy driver 35 deforms through current excitation to achieve precise control of the curvature radius of the working surface of the flexible polishing head 6. The core function of the connecting rod assembly 3 is to precisely magnify and transmit force and displacement to the curvature adjustment head 4 by adjusting the proportional relationship between the fulcrum position and the lever arm length. In this embodiment, the material of the shape memory alloy driver 35 is nickel-titanium alloy, which has good shape memory effect and fatigue resistance.

[0032] The top of the connecting rod assembly 3 is connected to a curvature adjustment head 4. The curvature adjustment head 4 is as Figure 4 shown in the figure. Its outer contour is hemispherical, and the curvature adjustment head 4 is provided with multiple layers of voids. A flexible polishing head 6 is arranged above the curvature adjustment head 4. The flexible polishing head 6 is in direct contact with the curvature adjustment head 4, and the flexible polishing head 6 adjusts the curvature radius of the working surface through the curvature adjustment head 4. The flexible polishing head 6 is in direct contact with the surface of the optical element to perform precision polishing on the optical element. It is required that the flexible polishing head 6 is a flexible material with high elastic modulus and wear resistance to ensure that it can adapt to the surfaces of optical elements with different curvatures during the polishing process.

[0033] The curvature adjustment head 4 adopts a multi-layer stacked structure design, with precisely calculated gaps provided between each layer, enabling it to generate controllable deformation when subjected to the force of the connecting rod assembly 3. The design of the multi-layer gap structure not only improves the flexibility of the curvature adjustment head 4 but also makes the curvature adjustment smoother and more continuous, avoiding the discontinuous deformation that may occur in the traditional single-layer structure during the adjustment process. In this embodiment, the material of the curvature adjustment head 4 is a titanium alloy with an elastic modulus of 80 - 120 GPa, having excellent elastic recovery ability and long-term stability.

[0034] The adjustment of the working surface curvature radius of the flexible polishing head 6 is specifically as follows: When the flexible polishing head 6 is pushed or pulled by the curvature adjustment head 4, it can undergo precise and controllable shape changes, and the curvature adjustment head 4 is subjected to the force of the connecting rod assembly 3. This enables the flexible polishing head 6 to adjust the curvature radius of its working surface in real time and precisely to adapt to the workpiece surfaces with different curvatures when polishing different positions of the workpiece. By controlling the axial (up and down) movement of the curvature adjustment head 4, the curvature radius of the central region of the flexible polishing head 6 can be changed, as Figure 5 shown; by controlling the angular swing (tilt) of the curvature adjustment head 4, the curvature radius of the edge region of the flexible polishing head 6 can be adjusted, as Figure 6 shown; this design improves the accuracy and adaptability of the polishing process.

[0035] A protective shell 7 is provided on the outside of the connecting rod assembly 3. The flexible polishing head 6 and the protective shell 7 are connected through a grinding head frame 5, and a drive circuit is provided for the overall device. The drive circuit is used to output an excitation current to the shape memory alloy actuator 35, triggering the austenite phase transformation of the memory alloy through the Joule heat effect to generate deformation, and its control principle is as Figure 7As shown in the figure. The drive circuit includes a main control system. The main control system receives signal inputs from the machining path storage unit and the workpiece topography measurement module. The main control system inputs a control quantity to the shape memory alloy actuator control module. The shape memory alloy actuator control module drives the link assembly to move and amplifies the displacement acting on the curvature adjustment head. The curvature adjustment head controls the flexible polishing head to generate deformation and is used for workpiece machining. The drive circuit is provided with a power supply module to provide power supply for the entire system. Specifically: The drive circuit applies a specific control current to each shape memory alloy actuator 35. The heat generated by the current will trigger a phase change in the shape memory alloy material, causing it to elongate or shorten, generating a precisely controllable small displacement. This displacement is then amplified by the lateral amplification link 36. The amplified force or displacement directly drives the curvature adjustment head 4, causing it to generate a corresponding axial displacement or angular swing. Each partition of the partition base 1 is equipped with an independent shape memory alloy actuator 35. By controlling the device as a whole through the drive circuit, the telescopic amounts of the shape memory alloy actuators 35 in different partitions can be coordinated to precisely control the tilt angle and posture of the curvature adjustment head 4. Finally, independent and fine control of the curvature radius of different regions of the flexible polishing head 6 is achieved.

[0036] When the polishing head described in this embodiment is in operation, the specific working process is as follows:

[0037] S1. Install the workpiece to be machined in a special fixture to ensure that the surface of the workpiece is completely immersed in the polishing fluid medium. For optical elements, fixation is generally achieved through a vacuum adsorption system; for mechanical parts, a mechanical fixture or an electromagnetic adsorption system can be selected for fixation according to the material characteristics and shape of the workpiece.

[0038] S2. Install the polishing head described in this embodiment on the polishing equipment through the positioning block 2. Control the polishing head to approach the surface of the workpiece. The polishing head gently contacts the surface of the workpiece to complete tool setting, and the system automatically records the current position as the machining reference surface.

[0039] S3. Start the rotating mechanism to make the workpiece to be polished rotate at a high speed. The polishing head polishes the workpiece according to the shape and machining requirements of the workpiece along the pre-set polishing path; during the polishing process, the polishing head can automatically adjust the curvature radius of the working surface according to the curvature of the polishing area where it is located to meet the machining requirements of complex curved surfaces.

[0040] S4. The drive circuit outputs a programmable excitation current to the shape memory alloy actuator 35, triggers the austenite phase transformation of the memory alloy through the Joule heat effect, generates a controllable deformation, and this deformation is transmitted to the flexible polishing head 6 through the connecting rod assembly 3 to achieve dynamic adjustment of the curvature radius of the working surface. The partitioned base 1 adopts an independent control unit array, and each partition can be individually excited to achieve local correction of the curvature of the working surface. For optical elements, such adjustment can significantly improve the surface roughness and surface shape accuracy. For mechanical parts, such adjustment can optimize the surface quality and material removal efficiency.

[0041] S5. During the polishing process, the workpiece morphology measurement module monitors the surface shape of the workpiece in real time, feeds the measurement data back to the main control system. The main control system calculates the required curvature adjustment amount for each partition according to the preset surface shape accuracy requirements, and correspondingly adjusts the excitation current of each shape memory alloy actuator control module to form a closed-loop control system to ensure the accuracy stability during the polishing process.

[0042] Therefore, the present invention adopts the above-mentioned precision polishing head with partitioned and controllable deformation. Through the partitioned base and the independent shape memory alloy actuator array, it can independently control the curvature radius of the center and edge of the flexible polishing head, optimize the edge pressure distribution, bring more stable contact stiffness and more uniform pressure distribution, suppress or compensate for the problems of excessive or insufficient removal at the edge caused by factors such as the change of linear velocity, improve the surface shape accuracy of the workpiece edge, and achieve finer and more localized surface shape control. At the same time, the shape memory alloy actuator is a solid-state drive element, and with the transverse amplification connecting rod, it can achieve the required driving force and displacement in a relatively compact space, and is easy to be integrated into the existing polishing equipment or robot system.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements do not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A precision polishing grinding head with partitionable and controllable deformation, characterized in that: It includes a partition base, a positioning block is arranged at the center below the partition base, at least one group of connecting rod assemblies are arranged above the partition base, the connecting rod assembly includes a shape memory alloy driver, a curvature adjusting head is connected to the top of the connecting rod assembly, a flexible polishing head is arranged above the curvature adjusting head, a protective shell is arranged on the outside of the connecting rod assembly, the flexible polishing head and the protective shell are connected through a grinding head frame, and the device as a whole is provided with a driving circuit, and the driving circuit controls the shape memory alloy driver to realize partitioned controllable deformation of the flexible polishing head.

2. The partitionable and controllably deformable precision polishing grinding head according to claim 1, characterized in that: The partition base is provided with at least one partition unit, and the partition units are evenly distributed on the surface of the partition base. The connecting rod assembly corresponds to the number and position of the partition units, and the connecting rod assembly is used to independently control the partitions of the flexible polishing head.

3. The partitionable and controllably deformable precision polishing grinding head according to claim 1, characterized in that: The connecting rod assembly includes a base, which is connected to the partition base by bolts, a fork rod and a driver support rod are arranged in parallel above the base, the top of the driver support rod is connected to the shape memory alloy driver, the shape memory alloy driver and the fork rod are movably connected through a transverse enlargement connecting rod, the tail end of the transverse enlargement connecting rod is hinged with a first connecting rod, the first connecting rod is hinged with a second connecting rod, the second connecting rod is connected to the curvature adjustment head, and the second connecting rod is used to transmit the displacement of the shape memory alloy driver to the curvature adjustment head.

4. The partitionable and controllably deformable precision polishing grinding head according to claim 3, characterized in that: The shape memory alloy driver is connected to the head end of the transverse amplifying connecting rod, and the fork rod is connected to the middle section of the transverse amplifying connecting rod.

5. The partitionable and controllably deformable precision polishing grinding head according to claim 1, characterized in that: The outer contour of the curvature adjusting head is hemispherical, and the curvature adjusting head is provided with a gap. The gap structure is used to generate controllable deformation when the curvature adjusting head is subjected to force.

6. The partitionable and controllably deformable precision polishing grinding head according to claim 1, characterized in that: The flexible polishing head is in direct contact with the curvature adjusting head, and the flexible polishing head adjusts the curvature radius of the working surface through the curvature adjusting head.

7. The partitionable and controllably deformable precision polishing grinding head according to claim 3, characterized in that: The driving circuit includes a main control system, which receives signal inputs from a processing path storage unit and a workpiece shape measurement module. The main control system inputs a control quantity to a shape memory alloy driver control module. The shape memory alloy driver control module drives the connecting rod assembly to move and amplifies the displacement effect on the curvature adjustment head. The curvature adjustment head controls the flexible polishing head to produce deformation and is used for workpiece processing. The driving circuit is provided with a power supply module.

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