A polishing device and method based on photorheological polishing fluid

Abstract

The present invention discloses a polishing device and method based on photorheological polishing fluid. The photorheological polishing fluid flows from a constant-temperature water bath through a shunt pipe, a feed pipe, and a spray head into a polishing tank. Under the action of a high-viscosity rotor pump, it enters a main channel and flows back into the constant-temperature water bath. A control end controls the high-viscosity rotor pump based on feedback from a liquid level detector to maintain a constant liquid level in the polishing tank. The control end controls the opening and closing of an electrically controlled valve to enable a viscosity detector to quantitatively measure the viscosity of the polishing fluid, which is then fed into the main channel. The control end receives data detected by the viscosity detector, a temperature detector, and a dynamic torque sensor, and controls the heating temperature of the constant-temperature water bath, the intensity of ultraviolet lamp 1, the cooling or heat generation of the semiconductor cooling plate, the intensity of ultraviolet lamp 2 and the white light lamp, and the intensity of the laser emitted by the ultraviolet laser emitter. The present invention achieves in-situ, real-time, and precise control of the viscosity of the photorheological polishing fluid in the polishing area.

Description

Technical Field

[0001] The present invention relates to the field of surface ultra-precision machining, and in particular to a polishing device and method based on photorheological polishing fluid. Background Art

[0002] Ultra-precision surface machining technology has numerous applications in areas such as optical device surface machining, semiconductor surface machining, and medical device surface machining. Ultra-precision polishing is often the final step in part processing. The quality of the polished surface directly impacts the function of the part, especially for parts with curved optical surfaces. Surface damage and changes in surface shape during the polishing process can severely impact the function of the optical surface. In recent years, rheological polishing techniques such as shear thickening polishing, magnetorheological polishing, electrorheological polishing, and photorheological polishing have been proposed and applied to ultra-precision surface polishing.

[0003] Photorheological polishing is a polishing method that uses photorheological materials to create a polishing slurry. These materials include azobenzene, diarylethenes, phenoxynaphthoquinones, spiropyrans, and their derivatives. A photorheological polishing slurry is prepared by adding a certain amount of photorheological material to an organic or inorganic solution, followed by an appropriate amount of surfactant and polishing powder. When exposed to ultraviolet or white light, the structure of this photorheological material undergoes a reversible change, causing the viscosity of the slurry to change. A small polishing head is positioned close to the workpiece and rotated, driving the photorheological polishing slurry nearby. This flowing slurry exerts dynamic pressure on the workpiece. Sufficient pressure forces tiny abrasive particles into the workpiece, forcing them to move along the surface, resulting in material removal. This pressure, in turn, removes material from the workpiece near the polishing head, altering the local surface profile. During the polishing process, changes in the slurry's viscosity alter the slurry's flow velocity and dynamic pressure on the workpiece surface, changing the polishing effect and affecting the material removal rate.

[0004] A Chinese invention patent (CN202011148254.X) has been granted. The patent name is "Photorheological polishing method and device with combined light-shear induced thickening effect." This method uses a polishing fluid with shear thickening and photorheological effects for polishing. Light is used to control and stabilize the viscosity of the polishing fluid, thereby improving the material removal rate. The polishing method in the above patent is flexible polishing of the entire surface. It is adaptable to the overall surface shape but does not actively control the local surface shape. It is not suitable for polishing and correcting complex surfaces. It does not consider the effect of temperature on the viscosity of the polishing fluid, nor does it consider the effect of the light-viscosity response speed of the polishing fluid on the change in the polishing fluid viscosity.

[0005] A Chinese invention patent (CN202211061942.1) has been published. The patent title is: A polishing system with synergistic photorheological, photochemical, and cavitation effects. The polishing tool can flexibly adapt to changes in the surface shape, adjust the angle of UV light irradiation, and utilize photorheological, photochemical, and cavitation effects to enhance the polishing effect. However, the system does not perform a comprehensive, real-time measurement of the viscosity of the polishing area, nor does it consider the effect of temperature on viscosity. Furthermore, the system does not consider the effect of the polishing fluid's photoviscosity response speed on viscosity changes.

[0006] A Chinese invention patent (CN201810188063.2) has been granted, titled "A Polishing Method and Apparatus Based on Photorheological Materials." This patent utilizes a mesh to secure a photorheological polishing body. Adjusting the wavelength of light irradiating the body adjusts the body's stiffness to achieve programmable polishing. However, this patent fails to consider the effects of exposure time and temperature on the stiffness of the photorheological polishing body. Furthermore, the patent lacks stiffness detection equipment within the polishing area for feedback control, resulting in limited control accuracy. Summary of the Invention

[0007] In view of the shortcomings of the prior art in photorheological polishing, such as weak control over the viscosity of the photorheological polishing fluid and weak control over the material removal rate, the present invention proposes a polishing device and method based on photorheological polishing fluid.

[0008] The specific technical solutions are as follows:

[0009] A polishing device based on photorheological polishing liquid, comprising: multiple high-viscosity rotor pumps, a main channel, a constant temperature water bath device, an ultraviolet lamp, an agitator, a feed pipe, a viscosity detector, an electric control valve, a temperature detector, a spray head, a polishing component, a workpiece to be processed, a liquid level detector, a polishing tank, and a control terminal;

[0010] The constant temperature water bath device contains photorheological polishing liquid, has an agitator at the center, an ultraviolet lamp at the top, a polishing liquid inlet at the side wall connected to the output end of the main channel, and a polishing liquid outlet at the bottom connected to the shunt pipe via a high-viscosity rotor pump; one branch of the shunt pipe is a feed pipe, a spray head is provided at the end of the feed pipe to connect to the polishing tank, and a number of temperature detectors are provided on the feed pipe to measure the internal fluid temperature, annular semiconductor cooling plates are uniformly arranged axially inside, and ultraviolet lamps and white light lamps with the same impact area are uniformly and staggered; another branch of the shunt pipe is connected to a viscosity tester via an electrically controlled valve, and the outlet of the viscosity tester is connected to the main channel via a high-viscosity rotor pump;

[0011] A liquid level detector is installed on the wall of the polishing tank, and a workpiece is fixed to the bottom. A port is opened on the bottom edge and connected to the main channel input end via a high-viscosity rotor pump. The polishing assembly is installed in the polishing tank through an actuator for polishing. It includes a transparent polishing head, a dynamic torque sensor, a spindle, and an ultraviolet laser emitter arranged coaxially in sequence along the axial direction. The polishing head is located near the workpiece and never contacts it. The laser emitted by the ultraviolet laser emitter passes through the dynamic torque sensor and the cavity in the spindle and is emitted from the polishing head.

[0012] The control end is used to receive data detected by the viscosity detector, and control the heating temperature of the constant temperature water bath device and the intensity of the ultraviolet lamp 1; receive data detected by the temperature detector and the dynamic torque sensor, and control the cooling or heat generation of the semiconductor cooling plate, the intensity of the ultraviolet lamp 2 and the white light lamp, and the intensity of the laser emitted by the ultraviolet laser emitter; receive data detected by the liquid level detector, and adjust the power of each high-viscosity rotor pump to keep the liquid level in the polishing pool stable.

[0013] Furthermore, the UV lamp 1, UV lamp 2, white light lamp, and UV laser emitter head all use PWM to adjust the irradiation intensity.

[0014] Furthermore, the feed pipe includes: a second ultraviolet lamp, a white light lamp, a semiconductor cooling sheet, and a pipe wall; the semiconductor cooling sheet is a ring structure, which is evenly fixed axially in the pipe wall, and its power, cooling or heat generation can be independently controlled; the second ultraviolet lamp and the white light lamp are evenly staggered on the inner wall of the pipe wall, and the two lamps are arranged in an array, and the areas affected by the second ultraviolet lamp and the white light lamp at the same axial position are the same, and the two have opposite effects on the viscosity of the photorheological polishing liquid; after the second ultraviolet lamp and the white light lamp are fixed on the inner wall of the pipe wall, the surface is covered with transparent glue to prevent them from direct contact with the photorheological polishing liquid.

[0015] Furthermore, the polishing assembly includes: a fixed plate and an adjustment frame, as well as a polishing head, a coupling, a dynamic torque sensor, another coupling, a spindle, and an ultraviolet laser emitter head arranged coaxially in sequence along the axial direction; a through hole is opened at the inner center of the polishing head, coupling and spindle, and the dynamic torque sensor is used to detect the torque of the spindle; the dynamic torque sensor and the adjustment frame are directly fixed on the fixed plate, and the spindle is installed on the fixed plate through the bearing seat; the fixed plate is fixed to the actuator; the ultraviolet laser emitter head is fixed by the adjustment frame and its position and posture are adjusted.

[0016] Furthermore, the polishing head includes: a transparent end, a concave lens, and a metal tube arranged in sequence along the axial direction; the interior of the metal tube is hollow, and is used for allowing the ultraviolet laser emitted by the ultraviolet laser emitter to pass through; the transparent end is fixedly connected to one end of the metal tube, and the concave lens is fixed at the junction of the metal tube and the transparent end, with the concave surface facing the metal tube, and is used to diverge the ultraviolet laser, and the diverged ultraviolet laser is emitted through the transparent end.

[0017] Furthermore, the material of the transparent end portion is selected from transparent silicon dioxide or transparent polyurethane with a hindered light stabilizer added.

[0018] A polishing method based on a photorheological polishing fluid is implemented based on the polishing device based on the photorheological polishing fluid, comprising the following steps:

[0019] S1: Pour the prepared photorheological polishing liquid into a constant temperature water bath device, and fix the workpiece to be processed in the polishing pool;

[0020] S2. Pre-controlling the viscosity of the photorheological polishing fluid: starting the agitator, ultraviolet lamp, constant temperature water bath, and high-viscosity rotor pump to circulate the photorheological polishing fluid in the polishing device. Specifically, the photorheological polishing fluid flows from the constant temperature water bath into the diverter pipe and feed pipe, flows through the ejector head into the polishing tank, enters the main flow channel under the action of the high-viscosity rotor pump, and then flows back into the constant temperature water bath. The control end controls each high-viscosity rotor pump based on the liquid level in the polishing tank obtained by the liquid level detector to maintain the liquid level of the photorheological polishing fluid in the polishing tank at a set height.

[0021] At the same time, the control end controls the electronically controlled valve to open, allowing a fixed amount of photorheological polishing fluid to flow into the viscosity tester. The electronically controlled valve is then controlled to close. After the viscosity test is completed, the fluid is pumped into the main channel by the high-viscosity rotor pump and subsequently flows back into the constant-temperature water bath. At this time, the control end controls the electronically controlled valve to open again to conduct a new round of viscosity testing. The control end adjusts the irradiation intensity of the UV lamp 1 and the temperature of the constant-temperature water bath according to the viscosity results detected by the viscosity tester, so that the overall viscosity of the photorheological polishing fluid in the constant-temperature water bath remains within a set range.

[0022] S3. Perform quasi-precise feedback control on the viscosity of the photorheological polishing fluid: control the actuator to drive the polishing assembly to move so that the transparent end of the polishing head is immersed in the polishing tank, and during the first operation, the transparent end is away from the workpiece; start the spindle, and continuously and in real time detect the torque through the dynamic torque sensor, thereby obtaining the viscosity of the photorheological polishing fluid in the polishing area, wherein the polishing area is the area near the transparent end; the temperature detector detects the temperature of the photorheological polishing fluid in the feed pipe in real time, and the control end receives and analyzes the temperature and viscosity feedback, controls the irradiation intensity of the second ultraviolet lamp and the white light lamp in the feed pipe, and the power of the semiconductor cooling plate, so that the viscosity of the photorheological polishing fluid output from the feed pipe is stabilized near the target viscosity;

[0023] S4. Precise feedback control of the viscosity of the photorheological polishing fluid: The control actuator drives the polishing assembly to move to the area to be processed. The control end obtains the real-time viscosity of the polishing area based on the real-time torque detected by the dynamic torque sensor, thereby controlling the laser intensity emitted by the UV laser emitter and adjusting the viscosity of the photorheological polishing fluid in the polishing area to the target viscosity;

[0024] S5: Repeat S2-S4 and adjust the viscosity of the photorheological polishing fluid in real time until the polishing of the workpiece is completed.

[0025] Furthermore, the photorheological polishing liquid includes: a photosensitive substance, a solvent, and polishing powder; the photosensitive substance is selected to be a substance that can undergo reversible microstructural changes under visible light or ultraviolet light, and the solvent is selected to be an organic solvent or an inorganic solvent according to the photosensitive substance; the polishing powder is selected from any one of aluminum oxide, silicon carbide, and silicon dioxide.

[0026] Furthermore, the wavelength of ultraviolet light emitted by the ultraviolet lamp 1, the ultraviolet lamp 2, and the ultraviolet laser emitter is within the range of 200-400 nm, and the specific wavelength is based on the spectral absorption characteristics of the photorheological material.

[0027] The beneficial effects of the present invention are:

[0028] The present invention utilizes a pre-viscosity control strategy combining pre-control, quasi-precise feedback control, and precise feedback control to achieve in-situ, real-time, and precise control of the viscosity of the photorheological polishing fluid in the polishing area, thereby enabling precise control of the material removal rate during the photorheological polishing process. This method also significantly reduces the uncertain effects of external factors such as temperature, humidity, and light on the material removal rate during the photorheological polishing process, enhancing the controllability and robustness of the polishing system. This allows for convenient and precise polishing of any workpiece fixed within the polishing tank with defined material removal, facilitating precise, controllable, and reliable surface shaping. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a polishing device based on photorheological polishing fluid in an embodiment of the present invention.

[0030] Figure 2 Schematic diagram of the structure of the feed pipe in an embodiment of the present invention.

[0031] Figure 3 Schematic diagram of the structure of the polishing assembly in an embodiment of the present invention.

[0032] Figure 4 Schematic diagram of the structure of the polishing head in an embodiment of the present invention.

[0033] Figure 5 Schematic diagram showing the change in viscosity of the photorheological polishing fluid with different illumination times in an embodiment of the present invention.

[0034] In the figure, there are photorheological polishing liquid 1, high viscosity rotor pump 2, constant temperature water bath device 3, UV lamp 1 4, stirrer 5, feed pipe 6, temperature detector 7, ejection head 8, polishing assembly 9, workpiece 10, liquid level detector 11, polishing pool 12, viscosity detector 13, electric control valve 14, main channel 15; UV lamp 2 601, white light lamp 602, semiconductor cooling plate 603, pipe wall 604; polishing head 901, coupling 902, dynamic torque sensor 903, fixing plate 904, main shaft 905, adjustment frame 906, UV laser emission head 907; transparent end 90101, concave lens 90102, metal tube 90103. DETAILED DESCRIPTION

[0035] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments. The purpose and effects of the present invention will become more apparent. The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0036] like Figure 1 As shown, a polishing device based on photorheological polishing liquid includes: multiple high-viscosity rotor pumps 2, a constant temperature water bath device 3, an ultraviolet lamp 4, an agitator 5, a feed pipe 6, a temperature detector 7, a spray head 8, a polishing assembly 9, a workpiece 10, a liquid level detector 11, a polishing pool 12, a viscosity detector 13, an electronically controlled valve 14, and a main channel 15.

[0037] The constant temperature water bath device 3 is a double-layer nested structure, wherein the inner cavity is used to hold the photorheological polishing liquid 1 to be heated, and the inner cavity is denoted as the stirring tank; the outer cavity is used to hold the heating liquid, generally hot water, and the outer cavity is denoted as the water bath cavity. The water bath cavity surrounds and covers the stirring tank, forming a sealed and fluid-circulating space between the two, so that the hot water in the water bath cavity heats the photorheological polishing liquid 1 in the stirring tank by heat conduction without direct contact with it. A stirrer 5 is also provided in the center of the stirring tank to stir the photorheological polishing liquid 1 so that it is evenly heated as a whole. Several ultraviolet lamps 4 are evenly installed on the top of the inner wall of the stirring tank, and their irradiation intensity is controlled using pulse width modulation (PWM). The reason why only ultraviolet lamps are arranged in the stirring tank but not white light lamps is: under normal circumstances, ultraviolet lamps increase the viscosity of the photorheological polishing liquid 1, while white light lamps reduce the viscosity of the photorheological polishing liquid 1, and the viscosity of the polishing liquid will gradually decrease when not exposed to light; the polishing liquid is in a low viscosity state after being prepared, and the polishing liquid needs to be in a high viscosity state during polishing, so only ultraviolet lamps are arranged, and the increase in viscosity is roughly controlled by feedback from the viscosity tester, and the irradiation can be stopped when the viscosity reaches the predetermined range.

[0038] A polishing liquid inlet is provided at the upper end of the side wall of the constant-temperature water bath 3, connecting the stirring tank to the output end of the main channel 15. The main channel 15 can be configured with multiple sections. A high-viscosity rotor pump 2 is connected to the polishing liquid main pipe 15 according to actual needs to drive the photorheological polishing liquid 1 to flow within the system. A polishing liquid outlet is provided at the bottom of the constant-temperature water bath 3, connecting the stirring tank to the inlet of a high-viscosity rotor pump 2 via a pipeline. This high-viscosity rotor pump 2 is referred to as the polishing liquid discharge pump, and its outlet is connected to a diversion pipe. One branch of the diversion pipe serves as a feed pipe 6. Based on the direction of liquid flow, the end closest to the bifurcation is the head end of the feed pipe 6, and the other end is the terminal end of the feed pipe 6. The feed pipe 6 is equipped with temperature detectors 7 at both ends and in the middle section to measure the temperature of the liquid within the pipe. A spray head 8 is installed at the end, located above the polishing tank 12. Another branch of the diversion pipe is connected to the inlet of a viscosity detector 13, and an electrically controlled valve 14 is installed on this branch. The outlet of the rotational viscosity detector 13 is connected to the main channel 15 through a pipeline. A high-viscosity rotor pump 2 is provided on the pipeline to drive the photorheological polishing liquid 1 into the main channel 15 and finally into the stirring tank.

[0039] A workpiece 10 is fixed to the bottom of a polishing tank 12. A level detector 11 is mounted on the wall of the tank to detect the level of the photorheological polishing fluid 1 within the tank. A polishing assembly 9 can be mounted on the end of an actuator, such as a robotic arm or machine tool, to polish the workpiece 10. A port is provided at the bottom edge of the polishing tank 12, connecting it to the input of a main flow channel 15. A high-viscosity rotor pump 2 is located near the input of the main flow channel 15. For ease of distinction, this is referred to as the polishing fluid discharge pump.

[0040] like Figure 2 As shown, the feed pipe 6 includes: a second ultraviolet lamp 601, a white light lamp 602, a semiconductor cooling plate 603, and a pipe wall 604. The semiconductor cooling plate 603 is an annular structure, evenly fixed in the pipe wall 604 at certain axial intervals, and can independently control its power, cooling, and heat generation. The second ultraviolet lamp 601 and the white light lamp 602 are evenly staggered on the inner wall of the pipe wall 604. The two lamps are arranged in an array. The second ultraviolet lamp 601 and the white light lamp 602 at the same axial position affect the same area. The two have opposite effects on the viscosity of the photorheological polishing liquid 1. In this embodiment, the second ultraviolet lamp 601 increases the viscosity of the photorheological polishing liquid 1, while the white light lamp 602 reduces the viscosity of the photorheological polishing liquid 1. After the second UV lamp 601 and the white light lamp 602 are fixed on the inner wall of the tube wall 604, their surfaces are covered with transparent glue to prevent the lamps from directly contacting the photorheological polishing liquid 1; both the second UV lamp 601 and the white light lamp 602 use PWM to adjust the irradiation intensity.

[0041] like Figure 3As shown, the polishing assembly 9 comprises a fixed plate 904 and an adjustment frame 906, along with a polishing head 901, a coupling 902, a dynamic torque sensor 903, another coupling 902, a spindle 905, and a UV laser emitter 907, all coaxially arranged along the axial direction. The polishing head 901, coupling 902, and spindle 905 each have a through-hole at their center. The polishing head 901 is positioned close to the workpiece 10 but does not contact it. The spindle 905 can be an electric spindle or a pneumatic spindle. The dynamic torque sensor 903 is connected to the polishing head 901 and spindle 905, respectively, via the coupling 902, to detect the torque of the spindle 905. The dynamic torque sensor 903 and adjustment frame 906 are directly fixed to the fixed plate 904, while the spindle 905 is mounted on the fixed plate 904 via a bearing seat. The polishing assembly 9 is directly connected to the end of an actuator such as a robotic arm or machine tool via the fixed plate 904. The ultraviolet laser emitting head 907 is fixed by the positioning screws on the adjustment frame 906. The position and posture of the ultraviolet laser emitting head 907 are adjusted by adjusting the positioning screws so that the ultraviolet laser emitted by the ultraviolet laser emitting head 907 can pass through the through hole in the main shaft 905 and reach the polishing head 901; the ultraviolet laser emitting head 907 uses PWM modulation technology to control the laser irradiation intensity, specifically by adjusting the ultraviolet laser PWM duty cycle to adjust the laser intensity.

[0042] like Figure 4 As shown, polishing head 901 includes, arranged axially in sequence: a transparent end portion 90101, a concave lens 90102, and a metal tube 90103. Metal tube 90103 is hollow, with one end fixedly connected to transparent end portion 90101 and the other end connected to coupling 902. Concave lens 90102 is fixed at the junction of metal tube 90103 and transparent end portion 90101, with its concave surface facing metal tube 90103, and is used to diverge ultraviolet laser light, which is emitted through transparent end portion 90101. In this embodiment, transparent end portion 90101 can be made of a transparent material that absorbs little ultraviolet light and is stable, such as transparent silica or transparent polyurethane containing a hindered light stabilizer.

[0043] The polishing device based on photorheological polishing fluid also includes a control terminal. This terminal receives data detected by the viscosity detector 13, three sets of temperature detectors 7, and the dynamic torque sensor 903. After analyzing and processing the data, the control terminal controls the heating temperature of the constant temperature water bath 3, the intensity of the ultraviolet lamp 1 4, the cooling or heating of the semiconductor cooling plate 603, the intensity of the ultraviolet lamp 2 601 and the white light lamp 602, and the intensity of the laser emitted by the ultraviolet laser emitter 907. Furthermore, the control terminal receives data detected by the liquid level detector 11 and adjusts the power of each high-viscosity rotor pump 2 to maintain a stable liquid level in the polishing tank 12.

[0044] like Figure 5As shown, the viscosity of the photorheological polishing fluid 1 will change due to the illumination intensity and illumination time of ultraviolet light and visible light. This viscosity change is not instantaneous, and there will be a certain delay in the viscosity response to the change in illumination. When the target viscosity set for the polishing area deviates too much from the current viscosity, the in-situ laser control of the polishing area will lose its effect, because the viscosity of the polishing area will be replaced by the newly flowing photorheological polishing fluid 1 in the circulation before it can be adjusted to the set polishing viscosity, thereby losing precise control over the viscosity of the polishing area and causing the material removal rate to be out of control during polishing.

[0045] To address the above problems, the present invention proposes a polishing method based on a photorheological polishing fluid. The method is implemented based on the above-mentioned polishing device and performs three-level control on the viscosity of the photorheological polishing fluid 1: pre-control, quasi-precise feedback control, and precise feedback control. The method specifically includes the following steps:

[0046] S1: Pour the prepared photorheological polishing liquid 1 into the constant temperature water bath device 3, and fix the workpiece 10 to be processed in the polishing pool 12. The photorheological polishing liquid 1 includes a photosensitive substance, a solvent, and polishing powder. The photosensitive substance can be azobenzene and its derivatives, spiropyran and its derivatives, phenoxy naphthoquinone compounds, and other substances that can undergo reversible microstructural changes under visible light or ultraviolet light, thereby changing the overall viscosity of the solution. Depending on the photosensitive substance, the solvent can be an organic solvent such as polyethylene glycol and silicone oil, or an inorganic solvent such as deionized water; among them, azobenzene and its derivatives, spiropyran and its derivatives are water-soluble, and inorganic solvents such as deionized water can be used; phenoxy naphthoquinone compounds can use organic solvents. The polishing powder is selected from any one of aluminum oxide, silicon carbide, and silicon dioxide.

[0047] S2: Start the stirrer 5, the ultraviolet lamp 4, the constant temperature water bath device 3, and the high viscosity rotor pump 2 to start the circulation system, and perform preliminary viscosity adjustment on the photorheological polishing liquid 1 in the constant temperature water bath device 3, i.e., pre-control.

[0048] Specifically, the photorheological polishing fluid 1 flows into the shunt pipe under the action of the high-viscosity rotor pump 2. The control end controls the opening of the electronically controlled valve 14, and a certain amount of the photorheological polishing fluid 1 flows into the viscosity tester 13 through a branch of the shunt pipe. At this time, the control end controls the closing of the electronically controlled valve 14. The viscosity tester 13 detects the viscosity of the incoming photorheological polishing fluid 1 and returns it to the control end. After the test is completed, the photorheological polishing fluid 1 is pumped into the main channel 15 through the directly connected high-viscosity rotor pump 2. The control end controls the opening of the electronically controlled valve 14 again and repeats the test. The control end adjusts the irradiation intensity of the ultraviolet lamp 4 and the temperature of the constant temperature water bath device 3 based on the viscosity test results of the viscosity tester 13, so that the overall viscosity of the photorheological polishing fluid 1 in the constant temperature water bath device 3 is within the set range, achieving rough pre-control.

[0049] At the same time, the majority of the photorheological polishing fluid 1 flows from the discharge head 8 into the polishing tank 12 through the other branch of the shunt pipe, namely the feed pipe 6. The control end controls the power of each high-viscosity rotor pump 2 based on the polishing fluid level data obtained by the level detector 11, maintaining the level of the photorheological polishing fluid 1 in the polishing tank 12 at a set height. In the polishing fluid circulation system, an excessively high initial injection velocity of the polishing fluid can affect the flow characteristics in the polishing area (i.e., the area near the transparent end 90101), thereby affecting the polishing effect. A too low initial injection velocity can lead to insufficient feed, causing the polishing head 901 to idle, resulting in insufficient polishing fluid in the polishing area. To address this issue, the power of the polishing fluid discharge pump is adjusted to adjust the depth of the polishing fluid in the polishing area, temporarily storing the polishing fluid, allowing the workpiece 10 to be polished while submerged in the polishing fluid. This approach further enhances the stability of the polishing fluid in the polishing area and significantly reduces the impact of the polishing fluid circulation settings on the flow of the polishing fluid in the polishing area.

[0050] S3: When the viscosity result detected by the viscosity detector 13 is stable within the set range, the control actuator moves the polishing assembly 9 so that the transparent end 90101 of the polishing head 901 is immersed in a certain depth in the photorheological polishing liquid 1 in the polishing pool 12, and during the first operation, the transparent end 90101 is away from the workpiece 10 being processed.

[0051] The spindle 905 is started, and the torque of the polishing head 901 is continuously, in real time, and in situ measured via the dynamic torque sensor 903. Based on the real-time torque, the control terminal further determines the viscosity of the photorheological polishing fluid 1 in the polishing area. Because the temperature of the photorheological polishing fluid 1 is easily affected by ambient temperature, pump temperature, and the trace frictional heat generated by polishing, the temperature of the photorheological polishing fluid 1 in the feed pipe 6 is also monitored in real time via a temperature detector 7. After receiving temperature and viscosity feedback, the control terminal analyzes and processes both and then controls the PWM duty cycle of the UV lamp 2 601 and the white light lamp 602 in the feed pipe 6 to adjust their respective luminous intensities, as well as the power of the semiconductor cooling plate 603. This allows for real-time regulation of the temperature of the photorheological polishing fluid 1 in the feed pipe 6, as well as the intensity of the UV and white light irradiation received, to stabilize the viscosity of the photorheological polishing fluid 1 near the target viscosity (i.e., within the set range), achieving quasi-precise feedback control.

[0052] S4: When the viscosity of the photorheological polishing fluid 1 output from the feed pipe 6 is stable within the set range, the control actuator moves the polishing assembly 9 to the area to be processed, and by controlling the laser intensity emitted by the ultraviolet laser emitter 907, the viscosity of the photorheological polishing fluid 1 in the polishing area is quickly adjusted to the target viscosity, thereby achieving precise feedback control, ensuring that the material removal is highly controllable, uniform and stable, reducing the impact of viscosity control errors on material removal, reducing the harmful effects on the surface quality of the workpiece, and improving the polishing accuracy.

[0053] S5: Repeat steps S2-S4, adjusting the viscosity of the photorheological polishing fluid in real time until the workpiece is polished. During the polishing process, the viscosity can be adjusted in real time according to the polishing needs until the target value is reached. This pre-viscosity control strategy solves the problem of difficult to timely control viscosity in the polishing area, which arises from the conflict between the response time of the photorheological polishing fluid and the rapid circulation and replacement of the photorheological polishing fluid during the polishing process.

[0054] In the present invention, the polishing liquid solvent may evaporate to varying degrees due to changes in the air humidity at the processing site, causing the polishing liquid to become thicker and the basic viscosity to increase. However, the viscosity control range of this polishing method is much larger than the viscosity increase caused by solvent evaporation during the polishing process, thereby reducing the uncertain influence of humidity on the viscosity of the polishing area and achieving precise material removal rate control.

[0055] Furthermore, in this embodiment, the wavelength of ultraviolet light emitted by all ultraviolet light sources (i.e., ultraviolet lamp 1 4, ultraviolet lamp 2 601, and ultraviolet laser emission head 907) is within the range of 200-400 nm, and the specific wavelength selected is based on the spectral absorption characteristics of the photorheological material.

[0056] Furthermore, in this embodiment, during the actual polishing process, the material removal rate can be controlled by real-time adjustment of variables such as the viscosity around the polishing area, the rotation speed of the polishing head, and the distance between the polishing head and the workpiece being processed. By changing the above parameters, feed speed, polishing trajectory, etc., the surface shape of the workpiece being processed can be further precisely controlled.

[0057] Those skilled in the art will understand that the foregoing descriptions are merely preferred embodiments of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art will still be able to modify the technical solutions described in the foregoing examples or substitute equivalents for some of the technical features therein. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the invention shall be included within the scope of protection of the invention.

Claims

1. A polishing device based on photorheological polishing fluid, characterized in that: include: Multiple high-viscosity rotor pumps, main flow channels, constant temperature water bath devices, UV lamps, agitators, feed pipes, viscosity testers, electronically controlled valves, temperature detectors, spray heads, polishing components, workpieces, liquid level detectors, polishing tanks, and control terminals; The constant temperature water bath device contains photorheological polishing liquid, has an agitator at the center, an ultraviolet lamp at the top, a polishing liquid inlet at the side wall connected to the output end of the main channel, and a polishing liquid outlet at the bottom connected to the shunt pipe via a high-viscosity rotor pump; one branch of the shunt pipe is a feed pipe, a spray head is provided at the end of the feed pipe to connect to the polishing tank, and a number of temperature detectors are provided on the feed pipe to measure the internal fluid temperature, annular semiconductor cooling plates are uniformly arranged axially inside, and ultraviolet lamps and white light lamps with the same impact area are uniformly and staggered; another branch of the shunt pipe is connected to a viscosity tester via an electrically controlled valve, and the outlet of the viscosity tester is connected to the main channel via a high-viscosity rotor pump; A liquid level detector is installed on the wall of the polishing tank, and a workpiece is fixed to the bottom. A port is opened on the bottom edge and connected to the main channel input end via a high-viscosity rotor pump. The polishing assembly is installed in the polishing tank through an actuator for polishing. It includes a transparent polishing head, a dynamic torque sensor, a spindle, and an ultraviolet laser emitter arranged coaxially in sequence along the axial direction. The polishing head is located near the workpiece and never contacts it. The laser emitted by the ultraviolet laser emitter passes through the dynamic torque sensor and the cavity in the spindle and is emitted from the polishing head. The control end is used to receive data detected by the viscosity detector, and control the heating temperature of the constant temperature water bath device and the intensity of the ultraviolet lamp 1; receive data detected by the temperature detector and the dynamic torque sensor, and control the cooling or heat generation of the semiconductor cooling plate, the intensity of the ultraviolet lamp 2 and the white light lamp, and the intensity of the laser emitted by the ultraviolet laser emitter; receive data detected by the liquid level detector, and adjust the power of each high-viscosity rotor pump to keep the liquid level in the polishing pool stable.

2. The polishing device based on photorheological polishing liquid according to claim 1, characterized in that: The UV lamp 1, UV lamp 2, white light lamp and UV laser emission head all use PWM to adjust the irradiation intensity.

3. The polishing device based on photorheological polishing liquid according to claim 1, characterized in that: The feed pipe includes: a second ultraviolet lamp, a white light lamp, a semiconductor cooling sheet, and a pipe wall; the semiconductor cooling sheet is a ring structure, which is evenly fixed axially in the pipe wall, and its power, cooling or heat generation can be independently controlled; the second ultraviolet lamp and the white light lamp are evenly staggered on the inner wall of the pipe wall, and the two lamps are arranged in an array, and the ultraviolet lamp and the white light lamp at the same axial position affect the same area, and the two have opposite effects on the viscosity of the photorheological polishing liquid; after the second ultraviolet lamp and the white light lamp are fixed on the inner wall of the pipe wall, the surface is covered with transparent glue to prevent them from direct contact with the photorheological polishing liquid.

4. The polishing device based on photorheological polishing liquid according to claim 1, characterized in that: The polishing assembly includes: a fixed plate and an adjustment frame, as well as a polishing head, a coupling, a dynamic torque sensor, another coupling, a spindle, and an ultraviolet laser emitter head arranged coaxially in sequence along the axial direction; a through hole is opened at the inner center of the polishing head, coupling and spindle, and the dynamic torque sensor is used to detect the torque of the spindle; the dynamic torque sensor and the adjustment frame are directly fixed on the fixed plate, and the spindle is installed on the fixed plate through a bearing seat; the fixed plate is fixedly connected to the actuator; the ultraviolet laser emitter head is fixed by the adjustment frame and its position and posture are adjusted.

5. The polishing device based on photorheological polishing liquid according to claim 1, characterized in that: The polishing head includes: a transparent end, a concave lens, and a metal tube arranged in sequence along the axial direction; the interior of the metal tube is hollow, used for allowing the ultraviolet laser emitted by the ultraviolet laser emitter to pass through; the transparent end is fixedly connected to one end of the metal tube, and the concave lens is fixed at the junction of the metal tube and the transparent end, with the concave surface facing the metal tube, used for diverging the ultraviolet laser, and the diverged ultraviolet laser is emitted through the transparent end.

6. The polishing device based on photorheological polishing liquid according to claim 5, characterized in that: The material of the transparent end portion is selected from transparent silicon dioxide or transparent polyurethane with hindered light stabilizer added.

7. A polishing method based on a photorheological polishing fluid, implemented based on the polishing device based on a photorheological polishing fluid according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: Pour the prepared photorheological polishing liquid into a constant temperature water bath device, and fix the workpiece to be processed in the polishing pool; S2. Pre-controlling the viscosity of the photorheological polishing fluid: starting the agitator, ultraviolet lamp, constant temperature water bath, and high-viscosity rotor pump to circulate the photorheological polishing fluid in the polishing device. Specifically, the photorheological polishing fluid flows from the constant temperature water bath into the diverter pipe and feed pipe, flows through the ejector head into the polishing tank, enters the main flow channel under the action of the high-viscosity rotor pump, and then flows back into the constant temperature water bath. The control end controls each high-viscosity rotor pump based on the liquid level in the polishing tank obtained by the liquid level detector to maintain the liquid level of the photorheological polishing fluid in the polishing tank at a set height. At the same time, the control end controls the electronically controlled valve to open, so that a fixed amount of photorheological polishing fluid flows into the viscosity tester, and then controls the electronically controlled valve to close. After the viscosity test is completed, the fluid is pumped into the main channel under the action of the high-viscosity rotor pump, and then flows back to the constant temperature water bath device; At this time, the control end controls the electronically controlled valve to open again and conducts a new round of viscosity testing. The control end adjusts the irradiation intensity of the UV lamp and the temperature of the constant temperature water bath according to the viscosity tester, so that the overall viscosity of the photorheological polishing liquid in the constant temperature water bath remains within the set range. S3. Perform quasi-precise feedback control on the viscosity of the photorheological polishing fluid: Control the actuator to drive the polishing assembly to move so that the transparent end of the polishing head is immersed in the polishing tank. During the first operation, the transparent end is away from the workpiece; The spindle is started, and the torque is continuously and in real time detected by a dynamic torque sensor to obtain the viscosity of the photorheological polishing fluid in the polishing area, which is the area near the transparent end. The temperature detector detects the temperature of the photorheological polishing fluid in the feed pipe in real time. The control end receives and analyzes the temperature and viscosity feedback, controls the irradiation intensity of the ultraviolet lamp and the white light lamp in the feed pipe, and controls the power of the semiconductor cooling plate to stabilize the viscosity of the photorheological polishing fluid output from the feed pipe at a level close to the target viscosity. S4. Precise feedback control of the viscosity of the photorheological polishing fluid: The control actuator drives the polishing assembly to move to the area to be processed. The control end obtains the real-time viscosity of the polishing area based on the real-time torque detected by the dynamic torque sensor, thereby controlling the laser intensity emitted by the UV laser emitter and adjusting the viscosity of the photorheological polishing fluid in the polishing area to the target viscosity; S5: Repeat S2-S4 and adjust the viscosity of the photorheological polishing fluid in real time until the polishing of the workpiece is completed.

8. The polishing method based on photorheological polishing fluid according to claim 7, characterized in that: The photorheological polishing liquid includes: a photosensitive substance, a solvent, and polishing powder; the photosensitive substance is selected to be a substance that can undergo reversible microstructural changes under visible light or ultraviolet light, and the solvent is selected to be an organic solvent or an inorganic solvent according to the photosensitive substance; the polishing powder is selected from any one of aluminum oxide, silicon carbide, and silicon dioxide.

9. The polishing method based on photorheological polishing fluid according to claim 7, characterized in that: The wavelength of the ultraviolet light emitted by the ultraviolet lamp 1, the ultraviolet lamp 2 and the ultraviolet laser emitter is in the range of 200-400 nm, and the specific wavelength is based on the spectral absorption characteristics of the photorheological material.

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