An ultrasonic-assisted reinforced liquid membrane shearing polishing device and method

Abstract

The application discloses a kind of liquid membrane shearing polishing device and method of ultrasonic assisted strengthening, including polishing device, workpiece clamp and polishing pool, further including ultrasonic generator, the ultrasonic generator is located at the bottom and side of polishing pool, and the ultrasonic generator ultrasonic transmission direction is opposite to the workpiece to be processed;The polishing device includes surface structured polishing disc, polishing disc driving mechanism, polishing disc positioning mechanism;The polishing device is set in the top of polishing pool, and workpiece clamp is set in the bottom of polishing pool;The workpiece clamp and surface structured polishing disc are all below the liquid level of polishing pool.The application is under the dual strengthening action of surface structured polishing disc and ultrasonic generator, and liquid membrane shearing effect is generated between workpiece and polishing disc, improves processing efficiency and processing surface uniformity, realizes workpiece surface efficient high-quality low-damage polishing.

Description

Technical Field

[0001] This invention relates to the field of ultra-precision polishing technology, specifically to an ultrasonic-assisted enhanced liquid film shear polishing device and method, which is suitable for efficient, high-quality, and low-damage processing of different materials. Background Technology

[0002] Ultra-precision polishing technology, due to its minimal material removal and high processing accuracy, is often used as the final processing method for ultra-smooth surfaces. It is widely applied in the processing of integrated circuit substrate materials, precision gyroscopes, laser fusion mirrors, and X-ray optical system lenses. In a sense, ultra-precision polishing technology plays a crucial role in supporting the latest scientific and technological advancements and is also an important indicator of a country's manufacturing technology level.

[0003] Ultra-precision polishing technology utilizes the mechanical and chemical actions of micro-abrasive particles, aided by acoustic, flow, and electromagnetic fields, to improve the surface roughness of workpieces and reduce or eliminate the altered layer on the workpiece surface, thereby obtaining a high-quality surface. Its processing precision can reach the nanometer level, and the surface roughness after processing can reach 10⁻⁶. -1 The nanometer level. Based on the contact state between the polishing tool and the workpiece during the polishing process, ultra-precision polishing technology can be divided into contact polishing and non-contact polishing.

[0004] Contact polishing refers to a processing method in which the polishing tool and the workpiece come into direct contact during the machining process, and material removal is achieved through the mechanical grinding and rolling action generated between the abrasive and the workpiece. The advantages of traditional contact polishing are high processing efficiency and the ability to achieve sub-nanometer level surface roughness. However, because the workpiece and the polishing tool disc are in direct contact, scratches are inevitably left on the workpiece surface during the processing of hard and brittle materials such as engineering ceramics, resulting in surface and subsurface damage. This cannot meet the processing requirements for ultra-smooth surfaces, leading to poor processing stability and repeatability.

[0005] Non-contact polishing refers to a polishing method in which the polishing tool and the workpiece do not come into contact during the processing. The polishing fluid is used to impact the workpiece surface, achieving a high degree of lattice integrity and surface accuracy. Non-contact polishing removes extremely small amounts of material, ranging from a few to a dozen atoms, resulting in a very low surface roughness and a workpiece surface free of surface and subsurface damage. It is often used as the final processing step in ultra-smooth surface finishing. Non-contact polishing can be used for polishing crystalline materials (emphasizing lattice integrity and physical properties) and optical components (focusing on surface roughness and shape accuracy).

[0006] However, traditional non-contact polishing techniques still have insurmountable drawbacks. For example, float polishing and bath polishing produce weak dynamic pressure effects, resulting in low processing efficiency; elastic emission machining has an extremely small effective processing area and low processing efficiency, making it unsuitable for processing large workpieces; in dynamic pressure float polishing, the magnitude of the liquid dynamic pressure is related to the structure and rotation speed of the polishing base. If the generated fluid dynamic pressure is too low, the workpiece will float too low, directly contacting the polishing pad and abrasive grains, and causing scratches on the workpiece surface. Therefore, how to comprehensively balance various indicators and explore new methods, investigate new processes, and develop new equipment has always been a key focus and challenge in the processing of hard and brittle materials. Summary of the Invention

[0007] To address the problems of poor polishing quality control, high equipment cost, and poor processing uniformity in current non-contact polishing devices, this invention provides a high-efficiency, high-quality, and low-damage ultrasonic-assisted liquid film shear polishing method and device, characterized by wide applicability, high processing efficiency and precision, and minimal processing of altered layers and damage.

[0008] The technical solution adopted by this invention to solve its technical problem is:

[0009] An ultrasonic-assisted enhanced liquid film shearing polishing device includes a polishing device, a workpiece fixture, and a polishing tank. It also includes an ultrasonic generator located at the bottom and side of the polishing tank, with the ultrasonic transmission direction of the generator directly facing the workpiece. The polishing device includes a surface-structured polishing disc, a polishing disc driving mechanism, and a polishing disc positioning mechanism. The polishing device is positioned at the top of the polishing tank, and the workpiece fixture is positioned at the bottom of the polishing tank. Both the workpiece fixture and the surface-structured polishing disc are located below the liquid surface in the polishing tank.

[0010] Furthermore, the workpiece fixture is provided with a workpiece fixture driving mechanism, the polishing pool remains stationary, and the polishing disc driving mechanism rotates relative to the workpiece fixture driving mechanism.

[0011] Furthermore, the ultrasonic generating device includes an ultrasonic generator and an ultrasonic generator PC-side control system, wherein the ultrasonic generator PC-side control system is used to control the vibration frequency and amplitude of the ultrasonic generator.

[0012] Furthermore, the workpiece fixture includes a chuck, a spring-loaded assembly, and a fixture housing; the spring-loaded assembly is disposed inside the fixture housing, and the chuck is disposed on the spring-loaded assembly. Pressing the chuck controls the spring-loaded assembly to cause the chuck to spring up and retract.

[0013] Furthermore, the polishing disc positioning mechanism includes a vertical lead screw and slider mechanism and a horizontal lead screw and slider mechanism disposed on the vertical lead screw and slider mechanism. The horizontal lead screw and slider mechanism has the same structure as the vertical lead screw and slider mechanism, both including a drive motor, a sliding lead screw, a side wing stabilizing sliding assembly, and a drive slider. The drive motor is connected to the sliding lead screw in a transmission manner, and the drive slider is disposed on the sliding lead screw and connected to the side wing stabilizing sliding assembly.

[0014] Furthermore, a 1-10mm gap is maintained between the surface-structured polishing disc and the workpiece to be processed, to ensure that a liquid film is formed between the workpiece and the polishing disc.

[0015] Furthermore, the surface of the surface-structured polishing disc is composed of alternating parallel regions and groove regions, and the ratio of the groove portion to the plane segment width from the inner circle end to the outer circle end is 0.3-0.7; the groove region of the surface-structured polishing disc is stepped and has four different structures, namely wedge-shaped groove, L-shaped groove, upper parabolic groove, and lower parabolic groove.

[0016] Furthermore, the surface of the surface-structured polishing disc has 12-60 groove areas.

[0017] Furthermore, an ultrasonic-assisted enhanced liquid film shearing polishing device also includes a polishing fluid filtration device, which is connected to the waste discharge port of the polishing tank to discharge the polishing fluid and filter large particles of debris, facilitating the cleaning and repeated use of the polishing equipment.

[0018] An ultrasound-assisted enhanced liquid film shear polishing method includes the following steps:

[0019] 1) Fix the workpiece to be processed on the workpiece fixture, and connect the workpiece fixture with the workpiece fixture drive mechanism;

[0020] 2) Adjust the polishing disc positioning mechanism to maintain a 1-10 mm gap between the workpiece to be processed and the surface-structured polishing disc, so as to ensure that a stable liquid film can be formed between the workpiece and the polishing disc.

[0021] 3) Add a non-Newtonian fluid polishing slurry with shear rheological effect to the polishing tank, and ensure that the slurry level is higher than the upper surface of the polishing pad;

[0022] 4) During the polishing process, the polishing disc moves relative to the workpiece. Under the interface constraint of the surface-structured polishing disc, a liquid film shearing effect is generated, causing the abrasive grains to impact the roughness peaks of the workpiece surface in an approximately horizontal manner.

[0023] 5) Start the ultrasonic generator and set the vibration frequency and amplitude to make the polishing liquid in the polishing tank vibrate rapidly, so as to enhance the uniformity of the distribution of abrasive and particle clusters.

[0024] The beneficial effects of this invention are as follows:

[0025] 1) The surface-structured polishing disc involved in this invention can be adapted to most actual processing situations and needs by adjusting the number of grooves and the ratio of the segment width (the ratio of the width of the groove portion to the width of the plane portion). The groove portion is set in a stepped shape to further enhance the horizontal removal rate of the abrasive grains on the rough peaks of the workpiece surface.

[0026] 2) This invention overcomes the problems of high cost, low processing efficiency and poor processing uniformity that are common in traditional non-contact polishing methods, and also overcomes the influence of centrifugal force on polishing fluid.

[0027] 3) This invention can effectively control the liquid film shearing effect near the workpiece by adjusting the amplitude and frequency of the ultrasonic wave, thereby achieving controllability of polishing.

[0028] 4) The device of the present invention is low in cost, easy to implement, and has a simple overall structure; it can achieve high-efficiency, high-quality, and low-damage polishing of the workpiece surface, and has great economic and social benefits. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0030] Figure 2 This is an overall structural diagram of the polishing device of the present invention;

[0031] Figure 3 This is a top view of the overall structure of the polishing device of the present invention;

[0032] Figure 4 These are schematic diagrams of four different surface-structured polishing discs in this invention; wherein (a) is a lower parabolic groove; (b) is an L-shaped groove; (c) is a wedge-shaped groove; and (d) is an upper parabolic groove.

[0033] Figure 5 This is a schematic diagram of the horizontal lead screw and slider mechanism of the present invention;

[0034] Figure 6 This is a schematic diagram of the workpiece fixture structure of the present invention;

[0035] Figure 7 This is a schematic diagram illustrating the polishing principle of the present invention;

[0036] Figure 8 The diagram shows a partial view of the groove at point A; (a) a lower parabola; (b) an upper parabolic groove; (c) an L-shaped groove; and (d) a wedge-shaped groove.

[0037] Figure 9This is a partial schematic diagram of the polishing principle; (a) is a magnified view of part B; (b) is a magnified view of part C.

[0038] In the diagram: 1. Polishing disc drive mechanism; 2. Surface-structured polishing disc; 3. Polishing pool; 4. Polishing slurry filtration device; 5. Polishing equipment base; 6. Workpiece clamp; 61. Chuck; 62. Spring-up assembly; 63. Clamp housing; 7. Ultrasonic generator PC-end control system; 8. Ultrasonic generator; 9. Workpiece to be processed; 10. Polishing disc groove; 11. Horizontal lead screw and slider mechanism; 12. Vertical lead screw and slider mechanism; 121. Drive motor; 122. Sliding lead screw; 123. Side wing stabilizing sliding assembly; 124. Drive slider; 13. Housing; 14. Abrasive; 15. Solid colloidal particles; 16. Polishing slurry base liquid; 17. Particle cluster; 18. Ultrasonic-assisted strengthening area. Detailed Implementation

[0039] The present invention will now be further described with reference to the accompanying drawings.

[0040] This invention proposes an ultrasonic-assisted liquid film shear polishing method and apparatus based on liquid film shear polishing. Under the dual reinforcement of a surface-structured polishing disc and an ultrasonic generator, a liquid film shear effect is generated between the workpiece and the polishing disc. During the polishing process, the high-speed shear liquid film increases the horizontal shearing force of the abrasive grains on the rough peaks of the workpiece surface. Simultaneously, it overcomes the influence of centrifugal force on the polishing fluid, thereby improving processing efficiency and surface uniformity, achieving efficient, high-quality, and low-damage polishing of the workpiece surface.

[0041] Reference Figure 1-8 An ultrasonic-assisted enhanced liquid film shearing polishing device includes a polishing equipment base 5, a polishing device, a workpiece fixture 6, an ultrasonic generator, and a polishing pool 3.

[0042] The polishing device includes a surface-structured polishing disc 2, a polishing disc drive mechanism 1, a polishing disc positioning device, a polishing device drive control system, and a polishing liquid filtration device 4.

[0043] The workpiece fixture 6 is equipped with a workpiece fixture drive mechanism and includes a chuck 61, a spring-loaded assembly 62, and a fixture housing 64. The spring-loaded assembly 62 is disposed inside the fixture housing 64, and the chuck 61 is disposed on the spring-loaded assembly 62. Pressing the chuck 61 controls the spring-loaded assembly 62 to drive the chuck 61 to spring up and retract. The workpiece fixture 6 can fix workpieces of various shapes, including balls, cylindrical rollers, flat surfaces, and other irregularly shaped workpieces. In this embodiment, the workpiece is attached to the workpiece fixture with paraffin wax, which can be melted by heating after use to remove the workpiece. The spring-loaded assembly 62 is similar to a ballpoint pen or a switch button; it can be pressed down to lock itself and pressed down again to spring up, facilitating the loading and unloading of workpieces.

[0044] A non-Newtonian fluid polishing slurry with shear rheological effect is added to the polishing tank 3. The polishing slurry filtration device 4 is connected to the waste discharge port of the polishing tank 3 to discharge the polishing slurry and filter large particles of debris, which facilitates the cleaning and repeated use of the polishing equipment.

[0045] The ultrasonic generator includes an ultrasonic generator 8 and an ultrasonic generator PC-side control system 7 for controlling the vibration frequency and amplitude of the ultrasonic generator. The ultrasonic generator is located at the bottom and side of the polishing tank 3, and the ultrasonic transmission direction of the ultrasonic generator is directly opposite the workpiece 9 to be processed.

[0046] The polishing device is set at the top of the polishing pool 3, and the workpiece clamp 6 is set at the bottom of the polishing pool 3. Both the workpiece clamp 6 and the polishing disc 2 are located below the liquid surface of the polishing pool 3.

[0047] The polishing device drive control system is used to control the polishing disc drive mechanism 1 and the workpiece clamp drive mechanism. The polishing disc drive mechanism 1 controls the rotation of the polishing disc, and the workpiece clamp controls the rotation of the workpiece. The polishing disc drive mechanism 1 and the workpiece clamp drive mechanism rotate relative to each other, while the polishing pool 3 remains stationary. This ensures that the polishing fluid is not affected by centrifugal force during the polishing process and is distributed at the edge of the polishing pool, thus guaranteeing the workpiece processing effect.

[0048] The polishing fluid filtration device 4 is connected to the waste discharge port to discharge the polishing fluid and filter large particles of debris, which facilitates the cleaning and repeated use of the polishing equipment.

[0049] The polishing disc positioning device is used to control the horizontal and vertical movement of the polishing disc. The polishing disc positioning device includes a vertical lead screw and slider mechanism 12 and a horizontal lead screw and slider mechanism 11 disposed on the vertical lead screw and slider mechanism 12. Both the horizontal lead screw and slider mechanism 11 and the vertical lead screw and slider mechanism 12 adopt lead screw and slider mechanisms, including a drive motor 121, a sliding lead screw 122, a side wing stabilizing sliding assembly 123 and a drive slider 124. The drive motor 121 is connected to the sliding lead screw 122, and the drive slider 124 is disposed on the sliding lead screw 122 and connected to the side wing stabilizing sliding assembly 123. The side wing stabilizing sliding assembly 123 is composed of a side wing stabilizing slider and a slide rail.

[0050] The surface of the surface-structured polishing disc 2 is composed of alternating parallel and grooved areas. The ratio of the width of the groove portion to the width of the plane segment from the inner circle end to the outer circle end is 0.3-0.7, i.e., the ratio of L1 to L2. This can increase the fluid pressure in the processing area and ensure that the fluid pressure distribution is relatively uniform.

[0051] The groove area of ​​the surface structured polishing disk 2 has four different structures: wedge groove, L-shaped groove, upper parabolic groove, and lower parabolic groove. The groove part is set in a stepped shape to further enhance the horizontal removal rate of abrasive grains on the surface roughness peaks of the workpiece.

[0052] refer to Figure 4 The surface of the surface-structured polishing disc has 12 to 60 groove areas.

[0053] A gap of 1~10 mm is maintained between the workpiece 9 to be processed and the surface structured polishing disk 2 to ensure that a liquid film can be formed between the workpiece and the polishing disk; the presence of the liquid film avoids direct contact wear between the workpiece and the polishing disk, and at the same time plays the role of uniform load bearing (uniform distribution of normal pressure).

[0054] After the ultrasonic generator is activated, the non-Newtonian fluid polishing slurry near the workpiece vibrates, enhancing the uniformity of the abrasive and particle cluster distribution and further strengthening the liquid film shearing effect, thereby achieving efficient, high-quality, and low-damage polishing of the workpiece surface.

[0055] refer to Figure 9 The distribution of abrasive and particle clusters in the ultrasonic-assisted strengthening area is more uniform, avoiding processing defects and low efficiency caused by a large accumulation of abrasive particles.

[0056] An ultrasound-assisted enhanced liquid film shear polishing method, the specific steps of which are as follows:

[0057] 1) Fix the workpiece 9 to be processed on the polishing workpiece fixture 6, and connect the workpiece fixture with the workpiece fixture drive mechanism at the bottom of the polishing tank;

[0058] 2) Adjust the polishing disc positioning mechanism to maintain a 1-10 mm gap between the workpiece to be processed and the surface-structured polishing disc, so as to ensure that a stable liquid film can be formed between the workpiece and the polishing disc.

[0059] 3) Add a non-Newtonian fluid polishing slurry with shear rheological effect to the polishing pool, and ensure that the level of the polishing slurry is higher than the upper surface of the surface-structured polishing disk 2;

[0060] 4) During the polishing process, the surface structured polishing disk 2 moves relative to the workpiece 9. Under the interface constraint of the surface structured polishing disk 2, a liquid film shearing effect is generated, causing the abrasive grains to impact the rough peaks of the workpiece surface in an approximately horizontal manner.

[0061] 5) Start the ultrasonic generator and set the vibration frequency and amplitude to make the polishing liquid in the polishing tank vibrate rapidly, so as to enhance the uniformity of the distribution of abrasive and particle clusters.

[0062] Example:

[0063] The polishing process of an ultrasound-assisted enhanced liquid film shear polishing device is as follows:

[0064] The surface-structured polishing disc 2 uses a wedge-shaped groove with 40 grooves. The ratio of the groove width to the plane segmentation width from the inner to the outer circle is 0.40. The polishing disc height is 25 mm, the groove depth is 12 mm, and the polishing pool height is 50 mm. The polishing disc material is polytetrafluoroethylene (PTFE). The workpiece 9 is connected to the polishing workpiece fixture 6. The polishing disc drive mechanism 1 is positioned above the polishing pool 3 by adjusting the vertical lead screw slider mechanism 12. The surface-structured polishing disc 2 is then installed onto the polishing disc drive mechanism 1. The position of the polishing disc drive mechanism 1 is controlled by the horizontal lead screw slider mechanism 11 and the vertical lead screw slider mechanism 12. The height of the surface-structured polishing disc 2 is adjusted downwards to contact the parallel area at the bottom of the polishing pool for positioning, and then moved upwards by 1 mm. Non-Newtonian fluid polishing liquid is added to a depth of 35 mm in the polishing pool, and the waste liquid outlet of the polishing liquid filter is closed. The device is started, with the workpiece drive mechanism speed set to 40 r / min and the polishing disc drive mechanism 1 speed set to 80 r / min. The workpiece is then polished for 30 minutes. After a minute, stop the equipment, adjust the vertical lead screw and slider mechanism 12 to place the polishing disc above the surface of the polishing liquid, take out the polishing tool fixture for measurement, and realize dynamic control of the entire polishing process to form higher quality polished parts.

[0065] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention; therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An ultrasonically assisted liquid film shearing polishing device, comprising a polishing device, a workpiece fixture (6), and a polishing tank (3), characterized in that, It also includes an ultrasonic generator, which is located at the bottom and side of the polishing tank (3), and the ultrasonic transmission direction of the ultrasonic generator is directly opposite to the workpiece (9) to be processed; the polishing device includes a surface-structured polishing disc (2), a polishing disc driving mechanism (1), and a polishing disc positioning mechanism; the polishing device is set at the top of the polishing tank (3), and the workpiece clamp (6) is set at the bottom of the polishing tank (3); the workpiece clamp (6) and the surface-structured polishing disc (2) are both located below the liquid surface of the polishing tank; The workpiece fixture (6) is provided with a workpiece fixture driving mechanism, the polishing pool (3) remains stationary, and the polishing disc driving mechanism (1) rotates relative to the workpiece fixture driving mechanism. The polishing disc positioning mechanism includes a vertical lead screw and slider mechanism (12) and a horizontal lead screw and slider mechanism (11) disposed on the vertical lead screw and slider mechanism (12). The horizontal lead screw and slider mechanism (11) has the same structure as the vertical lead screw and slider mechanism (12), both including a drive motor (121), a sliding lead screw (122), a side wing stabilizing sliding assembly (123), and a drive slider (124). The drive motor (121) is connected to the sliding lead screw (122) in a transmission connection. The drive slider (124) is disposed on the sliding lead screw (122) in cooperation with it, and the drive slider (124) is connected to the side wing stabilizing sliding assembly (123). The surface-structured polishing disc (2) maintains a gap of 1-10 mm with the workpiece to be processed to ensure that a liquid film is formed between the workpiece to be processed and the polishing disc; The surface of the surface-structured polishing disk (2) is composed of alternating parallel regions and groove regions, and the width ratio of the groove portion to the plane segment from the inner circle end to the outer circle end is 0.3-0.7; the groove region of the surface-structured polishing disk is stepped and has four different structures, namely wedge groove, L-shaped groove, upper parabolic groove, and lower parabolic groove.

2. The ultrasonic-assisted enhanced liquid film shearing and polishing device according to claim 1, characterized in that, The ultrasonic generator includes an ultrasonic generator (8) and an ultrasonic generator PC control system (7), which is used to control the vibration frequency and amplitude of the ultrasonic generator.

3. The ultrasonic-assisted enhanced liquid film shearing and polishing device according to claim 1, characterized in that, The workpiece fixture (6) includes a chuck (61), a spring-loaded assembly (62), and a fixture housing (64). The spring-loaded assembly (62) is located inside the fixture housing (64), and the chuck (61) is located on the spring-loaded assembly (62). By pressing the chuck (61), the spring-loaded assembly (62) is controlled to drive the chuck (61) to spring up and retract.

4. The ultrasonic-assisted enhanced liquid film shearing and polishing device according to claim 1, characterized in that, The surface of the surface-structured polishing disc (2) has 12-60 groove areas.

5. The ultrasonic-assisted enhanced liquid film shearing and polishing device according to claim 1, characterized in that, It also includes a polishing fluid filtration device (4), which is connected to the waste discharge port of the polishing pool (3) to discharge the polishing fluid and filter large particles of debris, so as to facilitate the cleaning and repeated use of the polishing equipment.

6. The liquid film shear polishing method of the ultrasonic-assisted enhanced liquid film shear polishing device according to any one of claims 1-5, characterized in that, Includes the following steps: 1) Fix the workpiece to be processed on the workpiece fixture, and connect the workpiece fixture with the workpiece fixture drive mechanism; 2) Adjust the polishing disc positioning mechanism to maintain a 1-10 mm gap between the workpiece to be processed and the surface-structured polishing disc, so as to ensure that a stable liquid film can be formed between the workpiece and the polishing disc. 3) Add a non-Newtonian fluid polishing slurry with shear rheological effect to the polishing tank, and ensure that the slurry level is higher than the upper surface of the polishing pad; 4) During the polishing process, the polishing disc moves relative to the workpiece. Under the interface constraint of the surface-structured polishing disc, a liquid film shearing effect is generated, causing the abrasive grains to impact the roughness peaks of the workpiece surface in an approximately horizontal manner. 5) Start the ultrasonic generator and set the vibration frequency and amplitude to make the polishing liquid in the polishing tank vibrate rapidly, so as to enhance the uniformity of the distribution of abrasive and particle clusters.

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