Polishing device and method based on photo-rheological polishing liquid

Abstract

The invention discloses a polishing device and method based on photo-rheological polishing liquid. The photo-rheological polishing liquid flows into a polishing pool from a constant-temperature water bath device through a flow dividing pipe, a feeding pipeline and a spraying head, enters a main flow channel under the action of a high-viscosity rotor pump and flows back into the constant-temperature water bath device; the control end controls the high-viscosity rotor pump according to the feedback of the liquid level detector, so that the liquid level height in the polishing pool is constant; the control end controls the electric control valve to open and close, so that the viscosity detector quantitatively detects the viscosity of the polishing solution; the control end receives data detected by the viscosity detector, the temperature detector and the dynamic torque sensor and controls the heating temperature of the constant-temperature water bath device, the intensity of the first ultraviolet lamp, refrigeration or heat production of the semiconductor cooling piece, the intensity of the second ultraviolet lamp and the white light lamp and the intensity of laser emitted by the ultraviolet laser emitting head. According to the invention, in-situ, real-time and accurate control of the viscosity of the photo-rheological polishing liquid in the polishing area is realized.

Description

Technical Field

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

[0002] Surface ultra-precision machining technology has a large number of applications in the fields of optical device surface machining, semiconductor surface machining, medical device surface machining, etc. Ultra-precision polishing in ultra-precision machining is often the last step in part machining. The quality of the surface after polishing directly affects the function of the part, especially parts such as optical surfaces. If the surface is damaged or the surface shape changes during the polishing process, it will seriously affect the function of the optical surface. In recent years, rheological polishing technologies such as shear thickening polishing, magnetorheological polishing, electrorheological polishing, and photorheology have been proposed and applied to ultra-precision surface polishing.

[0003] Photorheological polishing is a polishing method that uses photorheological materials to prepare polishing liquid for polishing. Photorheological materials include azobenzene, diarylethenes, phenoxy naphthoquinones, spiropyrans and other substances and their derivatives. A certain amount of photorheological material is added to an organic or inorganic solution, and then an appropriate amount of activator and polishing powder are added to prepare a photorheological polishing liquid. When the light-reversible photorheological polishing liquid is irradiated with ultraviolet light or white light, the structure of the photorheological material will undergo a reversible change, causing the photorheological polishing liquid to show a change in viscosity. A small polishing head is used to approach the workpiece and rotate to drive the nearby photorheological polishing liquid to flow. The flowing photorheological polishing liquid generates dynamic pressure on the workpiece. A sufficiently large pressure will press tiny abrasive particles into the workpiece and move them along the surface of the workpiece to produce material removal, thereby producing material removal on the surface of the workpiece close to the polishing head, and changing the local surface shape of the workpiece. During the polishing process, changes in the viscosity of the polishing liquid will change the flow speed and dynamic pressure of the polishing liquid on the surface of the workpiece, change the polishing effect, and affect the polishing material removal rate.

[0004] The Chinese invention patent (CN202011148254.X) has been authorized. The patent name is: Photorheological polishing method and device with light-shear combined induced thickening effect. Polishing is performed using a polishing liquid with shear thickening effect and photorheological effect. The viscosity of the polishing liquid is controlled and stabilized by light to improve the material removal rate. The polishing method of 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 complex surface polishing correction. It does not take into account the influence of temperature on the viscosity of the polishing liquid, nor does it take into account the influence of the light-viscosity response speed of the polishing liquid on the change of the viscosity of the polishing liquid.

[0005] The Chinese invention patent (CN202211061942.1) has been published. The patent name is: A polishing system with synergistic effects of photorheology, photochemistry and cavitation. The polishing tool can flexibly adapt to the changes in the surface shape of the curved surface, adjust the angle of ultraviolet light irradiation, and use photorheological effect, photochemical effect and cavitation effect to enhance the polishing effect. There is no overall detection of the viscosity effect of the polishing area in real time, and the effect of temperature on viscosity is not considered. At the same time, the effect of the light-viscosity response speed of the polishing liquid on the viscosity change of the polishing liquid is not considered.

[0006] The Chinese invention patent (CN201810188063.2) has been authorized. The patent name is: A polishing method and device based on photorheological materials. The patent uses a gauze to fix the photorheological polishing body, and adjusts the stiffness of the polishing body by adjusting the wavelength of light irradiated to the polishing body to achieve program-controlled polishing. The patent does not take into account the influence of illumination time and temperature on the stiffness of the photorheological polishing body. At the same time, the patent does not set a stiffness detection device in the polishing area for stiffness feedback control, and the control accuracy is not high. Summary of the invention

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

[0008] The specific technical solutions are as follows: A polishing device based on photorheological polishing liquid, comprising: a plurality of high-viscosity rotor pumps, a main flow channel, a constant temperature water bath device, an ultraviolet lamp, a stirrer, a feed pipeline, 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 pool, and a control end; The constant temperature water bath device contains photorheological polishing liquid, a stirrer is arranged in the center, an ultraviolet lamp is arranged on the top, a polishing liquid inlet is arranged on the side wall and is connected to the output end of the main channel, and a polishing liquid outlet is arranged on the bottom and is connected to the shunt pipe through a high-viscosity rotor pump; one branch of the shunt pipe is a feed pipe, a spray head is arranged at the end of the feed pipe and is connected to the polishing pool, and a number of temperature detectors are arranged on the feed pipe to measure the internal fluid temperature, annular semiconductor cooling sheets are evenly arranged in the axial direction inside, and ultraviolet lamps and white light lamps with the same influence area are evenly and staggeredly arranged; another branch of the shunt pipe is connected to a viscosity detector through an electric control valve, and the outlet of the viscosity detector is connected to the main channel through a high-viscosity rotor pump; A liquid level detector is installed on the wall of the polishing pool, a workpiece is fixed at the bottom, a port is opened at the bottom edge, and is connected to the main channel input end through a high-viscosity rotor pump; the polishing assembly is installed in the polishing pool through an actuator for polishing, and includes a transparent polishing head, a dynamic torque sensor, a spindle, and an ultraviolet laser emitter head coaxially arranged in sequence along the axial direction; the polishing head is located near the workpiece and never contacts it, and the laser emitted by the ultraviolet laser emitter head 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 transmitter; 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.

[0009] Furthermore, the UV lamp 1, the UV lamp 2, the white light lamp, and the UV laser emitter head all use PWM to adjust the irradiation intensity.

[0010] Furthermore, the feed pipeline includes: two ultraviolet lamps, 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 two ultraviolet lamps and the white light lamps 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 two ultraviolet lamps and the white light lamps at the same axial position are the same, and the effects of the two on the viscosity of the photorheological polishing liquid are opposite; after the two ultraviolet lamps and the white light lamps 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.

[0011] 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 transmitter head that are coaxially arranged 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 transmitter head is fixed by the adjustment frame and the position and posture are adjusted.

[0012] 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 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, the concave lens is fixed at the junction of the metal tube and the transparent end, and the concave surface faces the metal tube, for diverging the ultraviolet laser, and the diverged ultraviolet laser is emitted through the transparent end.

[0013] Furthermore, the material of the transparent end portion is selected from transparent silicon dioxide or transparent polyurethane with a hindered light stabilizer added.

[0014] A polishing method based on photorheological polishing liquid is implemented based on the polishing device based on photorheological polishing liquid, and comprises the following steps: 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-control the viscosity of the photorheological polishing liquid: start the agitator, ultraviolet lamp 1, constant temperature water bath device, and high viscosity rotor pump to make the photorheological polishing liquid circulate in the polishing device, that is, the photorheological polishing liquid flows from the constant temperature water bath device into the shunt pipe and the feed pipe, flows into the polishing pool through the ejection head, enters the main channel under the action of the high viscosity rotor pump, and then flows back to the constant temperature water bath device; the control end controls each high viscosity rotor pump according to the liquid level height in the polishing pool obtained by the liquid level detector, and maintains the liquid level of the photorheological polishing liquid in the polishing pool at a set height; At the same time, the control end controls the electric control valve to open, so that a fixed amount of photorheological polishing fluid flows into the viscosity tester, and then controls the electric control valve to close. After the viscosity test is completed, the fluid is pumped into the main flow 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 electric control valve to open again, and a new round of viscosity test is performed; the control end adjusts the irradiation intensity of the ultraviolet lamp 1 and the temperature of the constant temperature water bath device according to the viscosity result detected by the viscosity tester, so that the overall viscosity of the photorheological polishing fluid in the constant temperature water bath device is maintained within the set range; S3, quasi-precise feedback control of the viscosity of the photorheological polishing liquid: control the actuator to drive the polishing assembly to move, so that the transparent end of the polishing head is immersed in the polishing pool, and the transparent end is away from the workpiece during the first operation; start the spindle, and continuously and in real time detect the torque through the dynamic torque sensor, so as to obtain the viscosity of the photorheological polishing liquid in the polishing area, and the polishing area is the area near the transparent end; the temperature detector detects the temperature of the photorheological polishing liquid in the feed pipe in real time, and the control end receives the temperature and viscosity feedback and performs analysis and processing, controls the irradiation intensity of the ultraviolet lamp 2 and the white light lamp in the feed pipe, and the power of the semiconductor cooling sheet, so that the viscosity of the photorheological polishing liquid output from the feed pipe is stabilized near 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, and the control end obtains the real-time viscosity of the polishing area according to the real-time torque detected by the dynamic torque sensor, thereby controlling the laser intensity emitted by the ultraviolet laser transmitter head and adjusting the viscosity of the photorheological polishing fluid in the polishing area to the target viscosity; S5: Repeat S2-S4 to adjust the viscosity of the photorheological polishing liquid in real time until the polishing of the workpiece is completed.

[0015] 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.

[0016] Furthermore, the wavelength of 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.

[0017] The beneficial effects of the present invention are: The present invention uses a pre-viscosity control strategy of 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 liquid in the polishing area, thereby achieving precise control of the material removal rate during the photorheological polishing process. The method can also greatly reduce the uncertain influence of external factors such as temperature, humidity, and light on the material removal rate during the photorheological polishing process, thereby enhancing the control performance and robustness of the polishing system. On this basis, it is convenient and accurate to perform polishing of any workpiece fixed in the polishing pool with determined material removal, and it is convenient to perform precise, controllable, and reliable processing of the surface profile. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of a polishing device based on photorheological polishing fluid in an embodiment of the present invention.

[0019] Figure 2 Schematic diagram of the structure of the feed pipeline in the embodiment of the present invention.

[0020] Figure 3 Schematic diagram of the structure of the polishing assembly in the embodiment of the present invention.

[0021] Figure 4 Schematic diagram of the structure of the polishing head in the embodiment of the present invention.

[0022] Figure 5 Schematic diagram of the change of the viscosity of the photorheological polishing liquid with different illumination time in an embodiment of the present invention.

[0023] In the figure, photorheological polishing liquid 1, high viscosity rotor pump 2, constant temperature water bath device 3, ultraviolet lamp 1 4, stirrer 5, feed pipe 6, temperature detector 7, spray head 8, polishing assembly 9, workpiece 10, liquid level detector 11, polishing pool 12, viscosity detector 13, electric control valve 14, main channel 15; ultraviolet lamp 2 601, white light lamp 602, semiconductor cooling sheet 603, pipe wall 604; polishing head 901, coupling 902, dynamic torque sensor 903, fixing plate 904, spindle 905, adjustment frame 906, ultraviolet laser emission head 907; transparent end 90101, concave lens 90102, metal tube 90103. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below according to the accompanying drawings and preferred embodiments, and the purpose and effect of the present invention will become more clear. 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 used to explain the present invention and are not intended to limit the present invention.

[0025] 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 electric control valve 14, and a main channel 15.

[0026] 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 recorded as a stirring pool; the outer cavity is used to hold the heating liquid, generally hot water, and the outer cavity is recorded as a water bath cavity. The water bath cavity surrounds and covers the stirring pool, and a sealed and fluid-circulating space is formed between the two, so that the hot water in the water bath cavity heats the photorheological polishing liquid 1 in the stirring pool by heat conduction without direct contact with it. A stirrer 5 is also provided in the center of the stirring pool, which is used 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 pool, and pulse width modulation (PWM) is used to control the irradiation intensity. The reason why only ultraviolet lamps but not white light lamps are arranged in the stirring tank is: under normal circumstances, ultraviolet lamps increase the viscosity of the photorheological polishing liquid 1, and 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 preparation, 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.

[0027] The polishing liquid inlet is provided at the upper end of the side wall of the constant temperature water bath device 3, and the stirring pool is connected to the output end of the main channel 15; the main channel 15 can be set up in multiple sections, and the 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 in the system. The polishing liquid outlet is provided at the bottom of the constant temperature water bath device 3, and the stirring pool is connected to the inlet of a high viscosity rotor pump 2 through a pipeline; the high viscosity rotor pump 2 is recorded as a polishing liquid discharge pump, and its outlet is connected to the shunt pipe. One branch of the shunt pipe is used as a feed pipe 6. According to the liquid flow direction, the end close to the bifurcation is the head end of the feed pipe 6, and the other end is the end of the feed pipe 6. The feed pipe 6 is installed with temperature detectors 7 at both ends and the middle section for measuring the temperature of the liquid in the pipe; the end is installed with a spray head 8, and the spray head 8 is located above the polishing pool 12. Another branch of the shunt pipe is connected to the inlet of the viscosity detector 13, and an electric control valve 14 is arranged on the branch. The outlet of the rotation viscosity detector 13 is connected to the main channel 15 through a pipeline. A high-viscosity rotor pump 2 is arranged on the pipeline to drive the photorheological polishing liquid 1 to flow into the main channel 15 and finally flow into the stirring tank.

[0028] The workpiece 10 to be processed is fixed at the bottom of the polishing pool 12; the liquid level detector 11 is installed on the wall of the polishing pool 12, and is used to detect the height of the photorheological polishing liquid 1 in the polishing pool 12; the polishing assembly 9 can be installed at the end of an actuator such as a robot arm or a machine tool, and is used to polish the workpiece 10 to be processed. A port is provided at the bottom edge of the polishing pool 12, and the polishing pool 12 is connected to the input end of the main channel 15. A high-viscosity rotor pump 2 is provided near the input end of the main channel 15, and for the convenience of distinction, it is recorded as a polishing liquid discharge pump.

[0029] like Figure 2 As shown, the feed pipe 6 includes: a second ultraviolet lamp 601, a white light lamp 602, a semiconductor cooling sheet 603, and a tube wall 604. The semiconductor cooling sheet 603 is an annular structure, which is evenly fixed in the tube wall 604 at a certain axial interval, 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 tube wall 604, and the two lamps are arranged in an array. The areas affected by the second ultraviolet lamp 601 and the white light lamp 602 at the same axial position are the same, and 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, and 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, the surfaces of both 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.

[0030] like Figure 3As shown, the polishing assembly 9 includes: a fixed plate 904 and an adjustment frame 906, as well as a polishing head 901, a coupling 902, a dynamic torque sensor 903, another coupling 902, a spindle 905, and an ultraviolet laser emitting head 907 coaxially arranged in sequence along the axial direction. Among them, a through hole is opened at the inner center of the polishing head 901, the coupling 902 and the spindle 905; the polishing head 901 is close to the workpiece 10 to be processed 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 the spindle 905 respectively through the coupling 902, and is used to detect the torque of the spindle 905. The dynamic torque sensor 903 and the adjustment frame 906 are directly fixed on the fixed plate 904, and the spindle 905 is installed on the fixed plate 904 through a bearing seat; the polishing assembly 9 is directly connected to the end of the actuator such as a robot arm and a machine tool through 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 to reach the polishing head 901; the ultraviolet laser emitting head 907 uses PWM modulation technology to control the laser irradiation intensity, and specifically adjusts the laser intensity by adjusting the ultraviolet laser PWM duty cycle.

[0031] like Figure 4 As shown, the polishing head 901 includes: a transparent end 90101, a concave lens 90102, and a metal tube 90103 arranged in sequence along the axial direction. The metal tube 90103 is hollow inside, one end of which is fixedly connected to the transparent end 90101, and the other end is connected to the coupling 902; the concave lens 90102 is fixed at the junction of the metal tube 90103 and the transparent end 90101, and the concave surface is facing the metal tube 90103, and is used to diverge ultraviolet lasers, which are emitted through the transparent end 90101. In this embodiment, the material of the transparent end 90101 can be transparent silica, transparent polyurethane with hindered light stabilizer added, and other transparent materials that absorb less ultraviolet light and are stable.

[0032] The polishing device based on the photorheological polishing liquid also includes a control end, which receives data detected by the viscosity detector 13, three sets of temperature detectors 7, and the dynamic torque sensor 903, and after analyzing and processing the data, controls the heating temperature of the constant temperature water bath device 3, the intensity of the ultraviolet lamp 1 4, the cooling or heat generation of the semiconductor cooling sheet 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. In addition, the control end also receives the data detected by the liquid level detector 11, adjusts the power of each high viscosity rotor pump 2, and keeps the liquid level in the polishing pool 12 stable.

[0033] 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 loss of control over the material removal rate during polishing.

[0034] In view of the above problems, the present invention proposes a polishing method based on photorheological polishing liquid. The method is implemented based on the above polishing device, and performs three-level control of the viscosity of the photorheological polishing liquid 1, namely, pre-control, quasi-precise feedback control, and precise feedback control. The method specifically includes the following steps: 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 a polishing powder. The photosensitive substance can be azobenzene and its derivatives, spiropyran and its derivatives, phenoxy naphthoquinone compounds, etc., which can undergo reversible microstructural changes under visible light or ultraviolet light, thereby changing the overall viscosity of the solution. Depending on the different photosensitive substances, 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.

[0035] S2: Start the agitator 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.

[0036] Specifically, the photorheological polishing liquid 1 flows to the shunt pipe under the action of the high viscosity rotor pump 2, and the control end controls the electric control valve 14 to open, and a certain amount of the photorheological polishing liquid 1 flows into the viscosity detector 13 through a branch of the shunt pipe. At this time, the control end controls the closing of the electric control valve 14, and the viscosity detector 13 detects the viscosity of the photorheological polishing liquid 1 flowing in and returns to the control end. After the detection is completed, the photorheological polishing liquid 1 is pumped into the main channel 15 through the directly connected high viscosity rotor pump 2, and the control end controls the opening of the electric control valve 14 again to repeat the detection. The control end adjusts the irradiation intensity of the ultraviolet lamp 4 and the temperature of the constant temperature water bath device 3 according to the viscosity result detected by the viscosity detector 13, so that the overall viscosity of the photorheological polishing liquid 1 in the constant temperature water bath device 3 is within the set range, and a rough pre-control is achieved.

[0037] At the same time, most of the photorheological polishing liquid 1 flows from the discharge head 8 into the polishing pool 12 through another branch of the shunt pipe, namely the feed pipe 6. The control end controls the power of each high-viscosity rotor pump 2 according to the polishing liquid level data obtained by the liquid level detector 11, and maintains the liquid level of the photorheological polishing liquid 1 in the polishing pool 12 at a set height. In the polishing liquid circulation system, if the initial injection speed of the polishing liquid is too high, it will affect the flow characteristics of the polishing area (i.e., the area near the transparent end 90101), and thus affect the polishing effect. When the initial injection speed of the polishing liquid is too low, insufficient feeding will occur, causing the polishing head 901 to idle, and there will be too little polishing liquid in the polishing area. In response to this problem, by adjusting the power of the polishing liquid discharge pump and adjusting the depth of the polishing liquid in the polishing area, the polishing liquid is temporarily stored, so that the workpiece 10 to be processed is polished while being immersed in the polishing liquid. This method further enhances the stability of the polishing liquid in the polishing area and greatly reduces the problem that the flow of the polishing liquid in the polishing area is affected by the polishing liquid circulation setting.

[0038] 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.

[0039] The spindle 905 is started, and the torque of the polishing head 901 is obtained continuously, in real time, and in situ through the dynamic torque sensor 903. The control end further obtains the viscosity of the photorheological polishing liquid 1 in the polishing area according to the real-time torque. Since the temperature of the photorheological polishing liquid 1 is easily affected by the ambient temperature, the temperature of the pump, and the trace friction heat generated by polishing, the temperature of the photorheological polishing liquid 1 in the feed pipe 6 needs to be detected in real time through the temperature detector 7. After receiving the temperature and viscosity feedback, the control end analyzes and processes the two, and controls the PWM duty cycle of the ultraviolet lamp 2 601 and the white light lamp 602 in the feed pipe 6 to adjust the luminous intensity of the two, as well as the power of the semiconductor cooling sheet 603, so as to adjust the temperature of the photorheological polishing liquid 1 in the feed pipe 6 and the irradiation intensity of the ultraviolet light and white light in real time, so that the viscosity of the photorheological polishing liquid 1 is stabilized near the target viscosity (i.e., within the set range), and quasi-precise feedback control is achieved.

[0040] S4: When the viscosity of the photorheological polishing fluid 1 output from the feed pipe 6 is stabilized 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 harmful effects on the surface quality of the workpiece, and improving polishing accuracy.

[0041] S5: Repeat S2-S4 to adjust 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 needs of polishing until the target value is reached. This pre-viscosity control strategy solves the problem of difficulty in timely control of the viscosity of the polishing area caused by the contradiction between the response time of the photorheological polishing fluid and the rapid circulation and replacement of the photorheological polishing fluid during the polishing process.

[0042] In the present invention, the polishing liquid solvent may evaporate to varying degrees due to changes in 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 the polishing method is much larger than the viscosity increase caused by solvent evaporation during the polishing process. Therefore, it is possible to reduce the uncertain influence of humidity on the viscosity of the polishing area and achieve precise material removal rate control.

[0043] 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 in the range of 200-400 nm, and the specific wavelength selected is based on the spectral absorption characteristics of the photorheological material.

[0044] 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.

[0045] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. A polishing device based on photorheological polishing liquid, characterized in that: include: Multiple high-viscosity rotor pumps, main flow channel, constant temperature water bath device, ultraviolet lamp, agitator, feed pipeline, viscosity tester, electronically controlled valve, temperature detector, spray head, polishing assembly, workpiece to be processed, liquid level detector, polishing pool, control end; The constant temperature water bath device contains photorheological polishing liquid, a stirrer is arranged in the center, an ultraviolet lamp is arranged on the top, a polishing liquid inlet is arranged on the side wall and is connected to the output end of the main channel, and a polishing liquid outlet is arranged on the bottom and is connected to the shunt pipe through a high-viscosity rotor pump; one branch of the shunt pipe is a feed pipe, a spray head is arranged at the end of the feed pipe and is connected to the polishing pool, and a number of temperature detectors are arranged on the feed pipe to measure the internal fluid temperature, annular semiconductor cooling sheets are evenly arranged in the axial direction inside, and ultraviolet lamps and white light lamps with the same influence area are evenly and staggeredly arranged; another branch of the shunt pipe is connected to a viscosity detector through an electric control valve, and the outlet of the viscosity detector is connected to the main channel through a high-viscosity rotor pump; A liquid level detector is installed on the wall of the polishing pool, a workpiece is fixed at the bottom, a port is opened at the bottom edge, and is connected to the main channel input end through a high-viscosity rotor pump; the polishing assembly is installed in the polishing pool through an actuator for polishing, and includes a transparent polishing head, a dynamic torque sensor, a spindle, and an ultraviolet laser emitter head coaxially arranged in sequence along the axial direction; the polishing head is located near the workpiece and never contacts it, and the laser emitted by the ultraviolet laser emitter head 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 transmitter; 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 is characterized in that: The UV lamp 1, UV lamp 2, white light lamp and UV laser emitter 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 pipeline includes: two ultraviolet lamps, 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 two ultraviolet lamps and the white light lamps are evenly staggered on the inner wall of the pipe wall, and the two lamps are arranged in arrays, and the areas affected by the two ultraviolet lamps and the white light lamps at the same axial position are the same, and the effects of the two on the viscosity of the photorheological polishing liquid are opposite; after the two ultraviolet lamps and the white light lamps 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 transmitter head that are coaxially arranged in sequence along the axial direction; a through hole is opened at the inner center of the polishing head, the coupling, and the 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 transmitter 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 for passing the ultraviolet laser emitted by the ultraviolet laser emitting head; the transparent end is fixedly connected to one end of the metal tube, the concave lens is fixed at the junction of the metal tube and the transparent end, and the concave surface faces the metal tube, 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 photorheological polishing liquid, implemented based on the polishing device based on photorheological polishing liquid 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-control the viscosity of the photorheological polishing liquid: start the agitator, ultraviolet lamp 1, constant temperature water bath device, and high viscosity rotor pump to make the photorheological polishing liquid circulate in the polishing device, that is, the photorheological polishing liquid flows from the constant temperature water bath device into the shunt pipe and the feed pipe, flows into the polishing pool through the ejection head, enters the main channel under the action of the high viscosity rotor pump, and then flows back to the constant temperature water bath device; the control end controls each high viscosity rotor pump according to the liquid level height in the polishing pool obtained by the liquid level detector, and maintains the liquid level of the photorheological polishing liquid in the polishing pool 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 liquid flows into the viscosity tester, and then controls the electronically controlled valve to close. After the viscosity test is completed, the liquid is pumped into the main flow channel under the action of a high viscosity rotor pump, and then flows back to the constant temperature water bath device; At this time, the control end controls the electric control 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 device according to the viscosity results tested by the viscosity tester, so that the overall viscosity of the photorheological polishing liquid in the constant temperature water bath device is maintained within the set range; S3. Perform quasi-precise feedback control on the viscosity of the photorheological polishing liquid: control the actuator to drive the polishing assembly to move so that the transparent end of the polishing head is immersed in the polishing pool, and the transparent end is away from the workpiece during the first operation; The spindle is started, and the torque is continuously and real-time detected by a dynamic torque sensor, thereby obtaining the viscosity of the photorheological polishing liquid 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 liquid 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 ultraviolet lamp 2 and the white light lamp in the feed pipe, and the power of the semiconductor cooling sheet, so that the viscosity of the photorheological polishing liquid output from the feed pipe is stabilized near 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, and the control end obtains the real-time viscosity of the polishing area according to the real-time torque detected by the dynamic torque sensor, thereby controlling the laser intensity emitted by the ultraviolet laser transmitter head and adjusting the viscosity of the photorheological polishing fluid in the polishing area to the target viscosity; S5: Repeat S2-S4 to adjust the viscosity of the photorheological polishing liquid in real time until the polishing of the workpiece is completed.

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

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