A method and circulation system for ultra-precision grinding of complex thin-walled components based on the addition of W3 diamond particles.

Abstract

This invention provides a method and circulation system for ultra-precision grinding of complex thin-walled components based on the addition of W3 diamond particles. It relates to the field of ultra-precision machining technology and addresses the problem that existing machining methods cannot effectively guarantee the accuracy and quality of grinding while reducing wheel wear. The method includes: Step 1: Establishing a grinding fluid circulation system; Step 2: Preparing a water-oil mixed grinding fluid with added diamond particles; Step 3: Adding the prepared grinding fluid to the grinding fluid circulation system and stirring thoroughly for a stirring time T; Step 4: Delivering the thoroughly stirred grinding fluid to the grinding area of ​​the complex thin-walled component to be processed using a drive pump for ultra-precision grinding; Step 5: Recovering the grinding fluid during the grinding process and thoroughly mixing the recovered fluid with the existing grinding fluid. Considering fluid loss during processing, diamond particles and the water-oil mixture are periodically added to the grinding fluid until processing is complete.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultra-precision machining, in particular to a method for ultra-precision grinding of complex thin-walled components based on addition of W3 diamond particles and a circulation system. BACKGROUND

[0002] In recent years, with the increasing attention of the state to the fields of aviation, aerospace, navigation and national defense, various new equipment emerge in an endless stream, and the hemispherical resonator gyro plays an important role among them. As the core device of the hemispherical gyro, the machining quality and precision of the hemispherical resonator directly affect the use performance of the equipment. Ultra-precision machining has become the mainstream process for realizing the machining of hemispherical resonators due to its ultra-high machining efficiency and machining quality and low machining cost. However, in the actual ultra-precision grinding process, the sintered diamond abrasive particles will break or directly fall off when they contact the workpiece, thereby causing the cast iron matrix of the ball head grinding wheel to directly participate in the grinding process, greatly reducing the surface quality of the ground workpiece.

[0003] To solve this problem, replacing the grinding wheel or optimizing the grinding process parameters is the most commonly used way. Although the replacement of the grinding wheel can fundamentally solve the problem of abrasive particle falling off or breaking, it is difficult to grasp the replacement time, and replacing the grinding wheel undoubtedly increases the time cost of grinding. The optimization of grinding process parameters mainly reduces the grinding force by reducing the single cutting depth, thereby avoiding the phenomenon of abrasive particle falling off. This method can effectively ensure the grinding quality on the premise of avoiding the time cost caused by replacing the grinding wheel, but the weak stiffness of the grinding wheel may cause the small cutting depth processing to fail to guarantee the dimensional accuracy of the machined part. Therefore, how to reduce the influence caused by the falling off of the diamond abrasive particles of the grinding wheel on the premise of ensuring the existing grinding process parameters has become the key to realizing high-precision and high-quality ultra-precision grinding. SUMMARY

[0004] The technical problem to be solved by the present application is:

[0005] The existing machining method cannot effectively ensure the precision and quality of the grinding process on the basis of reducing the wear of the grinding wheel.

[0006] The technical scheme adopted by the present application to solve the above technical problem is:

[0007] The present application provides a method for ultra-precision grinding of complex thin-walled components based on addition of W3 diamond particles, comprising the following steps:

[0008] Step 1: build a grinding fluid circulation system;

[0009] Step 2: prepare a water-oil mixed grinding fluid with added diamond particles;

[0010] Step three: add the prepared grinding fluid into the grinding fluid circulation system for fully mixing, and the mixing time is T;

[0011] Step four: deliver the fully mixed grinding fluid into the grinding area of the complex thin-walled component to be processed by driving the pump, and carry out the ultra-precision grinding processing;

[0012] Step five: recycle the water-oil mixed grinding fluid with diamond particles added in the grinding process, fully mix the recycled grinding fluid with the existing grinding fluid, consider the liquid loss in the processing, and regularly supplement the W3 diamond particles and the water-oil mixture into the grinding fluid until the processing is completed.

[0013] Further, the diamond particles in step two are W3 diamond particles.

[0014] Further, the volume ratio of W3 diamond particles to the water-oil mixture in the water-oil mixed grinding fluid with diamond particles added in step two ranges from 3.8% to 5.5%.

[0015] Further, the calculation method of the mixing time T in step three is as follows:

[0016]

[0017] Further, the rotating speed of the pump in step four is set to 30 rpm.

[0018] Further, the W3 diamond particles and the water-oil mixture are supplemented into the grinding fluid in step five, specifically: W3 diamond particles are supplemented into the grinding fluid at a ratio of 0.45 cm 3 / L every 30 min, and the water-oil mixture is supplemented into the grinding fluid at a ratio of 30 mL / L.

[0019] Further, the determination method of the supplement amount of W3 diamond particles and the water-oil mixture supplemented into the grinding fluid in step five is as follows:

[0020] Step five one: separate the water-oil mixture and the W3 diamond particles in a certain volume of grinding fluid, and dry the separated W3 diamond particles;

[0021] Step five two: measure the volume of the dried and separated W3 diamond particles and the volume of the water-oil mixture;

[0022] Step five three: measure the volume of the diamond particles and the volume of the water-oil mixture under different grinding processing times according to the method of step five one and step five two, construct the relationship curve between the grinding time and the reduction amount of the diamond particles and the water-oil mixture, and obtain the supplement amount of W3 diamond particles and the water-oil mixture supplemented into the grinding fluid.

[0023] A kind of based on the grinding fluid circulation system of adding W3 diamond particles, the system includes: stirring device, drive pump, liquid supplementing device and recovery device;

[0024] The stirring device is used to fully stir the water-oil mixed grinding fluid with added diamond particles;

[0025] The drive pump is used to deliver the fully stirred grinding fluid to the grinding area of the complex thin-walled component to be processed;

[0026] The liquid supplementing device is used to supplement diamond particles and water-oil mixture to the grinding fluid;

[0027] The recovery device includes a liquid recovery tank and a liquid recovery drive pump, which are used to recover the grinding fluid during processing and fully mix the recovered grinding fluid with the existing grinding fluid;

[0028] The stirring device, drive pump and liquid supplementing device are connected by hoses;

[0029] The output end of the drive pump is connected with a hose and a spray tube in sequence, and the spray opening of the spray tube is aligned with the grinding area of the complex thin-walled component to be processed;

[0030] The liquid recovery tank, liquid recovery drive pump and stirring device are connected by hoses.

[0031] Further, the liquid supplementing device includes a diamond particle supplementing device and a water-oil mixture supplementing device, the diamond particle supplementing device includes an automatic feeder for periodically supplementing a volume of diamond particles to the grinding fluid, and the water-oil mixture supplementing device is installed with a liquid titrator for controlling the volume of water-oil mixture added.

[0032] Compared with the prior art, the present application has the following advantages:

[0033] (1) By adding W3 diamond particles to the grinding fluid, the present application can significantly improve the grinding surface quality and roughness of the complex thin-walled component without changing the grinding process parameters, and greatly reduce the polishing processing time, laying a foundation for efficient ultra-precision grinding.

[0034] (2) The water-oil mixed grinding fluid with added diamond particles as the grinding fluid can effectively reduce the wear of the ball head grinding wheel during ultra-precision grinding, reduce the frequency of in-situ dressing or replacement of the ball head grinding wheel, and save the processing cost.

[0035] (3) The method of the present application has certain universality and can be applied to ultra-precision grinding and polishing processes of spherical and aspherical structures. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 A flow chart of the method for processing a complex thin-walled component by super-precision grinding based on adding W3 diamond particles in an embodiment of the present application;

[0037] Figure 2 A schematic diagram of super-precision grinding in an embodiment of the present application;

[0038] Figure 3 A schematic diagram of a grinding fluid circulation system in an embodiment of the present application;

[0039] Figure 4 A roughness curve of the inner support rod corresponding to the volume of different diamond particles in an embodiment of the present application;

[0040] Figure 5 A curve of the stirring time, the volume of diamond abrasive particles and the volume ratio of the test mixed liquid in an embodiment of the present application;

[0041] Figure 6 A roughness curve of the inner support rod corresponding to different rotation speeds of the peristaltic pump in an embodiment of the present application;

[0042] Figure 7 A curve of the volume reduction amount changing with grinding time in an embodiment of the present application;

[0043] Figure 8 A schematic diagram of the liquid supplementing device structure in an embodiment of the present application;

[0044] Figure 9 A hemispherical resonator roundness and coaxiality test position in an embodiment of the present application. DETAILED DESCRIPTION

[0045] In the description of the present application, it should be noted that the terms "first", "second", "third" mentioned in the embodiments of the present application are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second", "third" can explicitly or implicitly include one or more of the features.

[0046] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0047] Specific implementation scheme one: as shown in the present application provides a method for processing a complex thin-walled component by super-precision grinding based on adding W3 diamond particles, comprising the following steps: Figure 1

[0048] Step one: build a grinding fluid circulation system;

[0049] ​Step two: prepare the water-oil mixed grinding fluid with diamond particles;

[0050] Step three: add the prepared grinding fluid into the grinding fluid circulation system and fully stir for T time;

[0051] Step four: deliver the fully stirred grinding fluid to the grinding area of the complex thin-walled component to be processed by driving the pump and carry out the ultra-precision grinding processing;

[0052] Step five: recycle the water-oil mixed grinding fluid with diamond particles during the grinding processing, fully mix the recycled grinding fluid with the existing grinding fluid, consider the liquid loss during the processing, regularly supplement the diamond particles and the water-oil mixture into the grinding fluid, and complete the processing.

[0053] As shown in Figure 2 , the tool moves along the cross profile line of the hemispherical resonator and the neutral surface, the nozzle sprays the water-oil mixed grinding fluid with diamond particles at a certain flow rate, the diamond particles fill the space between the hemispherical resonator and the tool, and the tool rotation drives the diamond particles to remove the material. This method can ensure that the tool maintains good precision and avoids the deterioration of the processing precision caused by the tool wear, and at the same time realizes the high quality and high precision of the ultra-precision grinding processing.

[0054] In this embodiment, the water-oil mixture is composed of multipurpose mineral water-soluble cutting oil and water, and Mobilcut 102-water-soluble cutting fluid is used, and the volume ratio of cutting oil: water is 1:50.

[0055] Specific implementation scheme two: the diamond particles in step two are W3 diamond particles. Other aspects of this embodiment are the same as those of specific implementation scheme one.

[0056] Specific implementation scheme three: the volume ratio of W3 diamond particles to the water-oil mixture in the water-oil mixed grinding fluid with diamond particles in step two is in the range of 3.8% to 5.5%. Other aspects of this embodiment are the same as those of specific implementation scheme two.

[0057] When the volume of the water-oil mixture is 1L, the surface roughness of the processed part is analyzed under the same grinding process parameters when the volume of the added W3 diamond particles is 5cm 3 , 10cm 3 , 15cm 3 , 20cm 3 , …, 50cm 3 , 55cm 3 , 60cm 3 , respectively. The result is shown in Table 1, and the peristaltic pump speed during processing is 25rpm.

[0058] Table 1

[0059] Diamond volume 5 cm 3 ]] 10 cm 3 ]] 15 cm 3 ]] 20 cm 3 ]] 25 cm 3 ]] 30 cm 3 ]] Surface roughness 105.22 nm 80.32 nm 66.58 nm 48.25 nm 40.29 nm 38.25 nm Diamond volume 35 cm 3 ]] 40 cm 3 ]] 45 cm 3 ]] 50 cm 3 ]] 55 cm 3 ]] 60 cm 3 ]] Surface roughness 34.85 nm 32.75 nm 32.62 nm 32.83 nm 33.18 nm 32.99 nm

[0060] According to the table results and the curve shown in Figure 4 When the volume of added diamond particles exceeds 40cm 3 , the roughness results obtained by processing are basically stable.

[0061] In addition, the optimal volume of W3 diamond particles when the water-oil mixture is 200mL, 400mL, 600mL, 800mL, and 1200mL is explored according to the above analysis method, and the results show that the grinding effect is best when the volume ratio of W3 diamond particles to water-oil mixture is 3.8% to 5.5%.

[0062] Specific implementation scheme four: the calculation method of the stirring time T is:

[0063]

[0064] Unit: hour.

[0065] The other aspects of this embodiment are the same as those of specific implementation scheme one.

[0066] W3 diamond particles are added to the grinding fluid respectively, so that the concentration of diamond particles in the grinding fluid is 10cm 3 / L, 15cm 3 / L, 20cm 3 / L, 25cm 3 / L, and 30cm 3 / L respectively, and 200mL of the mixture is taken out every 5min for heating and evaporation operation, and the remaining volume of diamond particles is measured, and the results are shown in Table 1.

[0067] Table 2

[0068]

[0069] From the data in Table 2, it can be seen that the mixture of W3 diamond particles with a concentration of 10cm 3 / L, 15cm 3 / L, 20cm 3 / L, 25cm 3 / L, and 30cm 3 / L is stable at 10min, 15min, 20min, 25min, and 30min respectively. At the same time, Figure 5 The relationship curve between the horizontal coordinate W3 diamond particle volume when the diamond particle volume is stable and the ratio of the test mixture volume (200mL) and the vertical coordinate of the stirring time is described.

[0070] Through Figure 5The linear fitting curve finally determines the parameter in this embodiment as 16.6. Wherein, the unit of stirring time T is h.

[0071] Specific embodiment five: the rotating speed of the driving pump in step four is set as 30 rpm. Other parts of this embodiment are the same as specific embodiment one.

[0072] Because the distance between the stirrer and the grinding area is relatively far, if only relying on the free flow of the mixed liquid in the stirring tank, on one hand, it cannot guarantee the outlet flow rate, and on the other hand, the uniformly stirred mixed liquid will also appear the phenomenon of diamond particle precipitation due to the too slow flow rate. Therefore, a driving pump (optional peristaltic pump) needs to be configured to realize the accelerated flow of the mixed liquid during the flow of the mixed liquid, and the rotating speed of the driving pump also becomes one of the key parameters affecting the grinding quality. As shown in Table 3, the volume ratio of diamond particles to water-oil mixture is 40 cm 3 / L, and the stirring time is sufficient, and the roughness of the complex thin-walled inner support rod under different rotating speeds of the driving pump.

[0073] Table 3

[0074]

[0075]

[0076] According to the curve change rule shown in Figure 6 , with the gradual increase of the rotating speed of the driving pump, the roughness of the complex thin-walled inner rod presents the trend of first rapidly decreasing and then slowly decreasing, but the overall change range is small. If a higher rotating speed of the driving pump is adopted, although the grinding quality can be relatively high, too fast rotation will reduce the service life of the hose and accelerate the loss of the W3 diamond particles and the water-oil mixture, and the grinding quality will not be qualitatively improved. Based on this, the rotating speed of the peristaltic pump in this embodiment is set as 30 rpm.

[0077] Specific embodiment six: the W3 diamond particles and the water-oil mixture are supplemented into the grinding fluid in step five, specifically: W3 diamond particles are supplemented into the grinding fluid at a proportion of 0.45 cm 3 / L every 30 min, and the water-oil mixture is supplemented into the grinding fluid at a proportion of 30 mL / L every 30 min. Other parts of this embodiment are the same as specific embodiment one.

[0078] Because of the volatilization of water during the processing and the accumulation of the mixed liquid in the storage tank, the volume ratio of the diamond particles to the water-oil mixture in the stirring tank cannot reach the best grinding effect after a period of processing, so it is necessary to regularly supplement the water-oil mixture and the diamond particles into the stirring tank.

[0079] Specific embodiment seven: the determination method of the supplement amount of the W3 diamond particles and the water-oil mixture supplemented into the grinding fluid in step five is:

[0080] Step five one: separate the water-oil mixture and W3 diamond particles in a certain volume of grinding fluid, and dry the separated W3 diamond particles;

[0081] Step five two: measure the volume of the dried separated W3 diamond particles and the volume of the water-oil mixture;

[0082] Step five three: according to the method of step five one and step five two, measure the volume of diamond particles and the volume of water-oil mixture under different grinding processing times respectively, construct the relationship curve of grinding time and the reduction amount of diamond particles and water-oil mixture, and obtain the replenishment amount of W3 diamond particles and water-oil mixture to the grinding fluid. The other parts of this embodiment are the same as embodiment six.

[0083] In this embodiment, for 1L grinding fluid, the volume of diamond particles and the volume of water-oil mixture are measured respectively at 30min, 60min, …, 270min, and 300min of grinding processing. The results are shown in Table 4;

[0084] Table 4

[0085]

[0086]

[0087] As can be seen from Table 4, the volume of water-oil mixture and diamond particles gradually decreases over time, which is consistent with the above analysis results.

[0088] According to the curve of Figure 7 , the volume of water-oil mixture decreases by 24mL-45mL every 30min, and the volume of diamond particles decreases by 0.35cm 3 -0.6cm 3 every 30min. Therefore, 30mL of water-oil mixture and 0.45cm 3 of diamond particles are added to each liter of grinding fluid every 30min during processing.

[0089] Embodiment eight: as shown in Figure 3 , a grinding fluid circulation system based on the addition of W3 diamond particles, the system comprising: a stirring device, a driving pump, a liquid supplementing device and a recovery device;

[0090] The stirring device is used for fully stirring the water-oil mixed grinding fluid with added diamond particles;

[0091] The driving pump is used for conveying the fully stirred grinding fluid to the grinding area of the complex thin-walled component to be processed;

[0092] The fluid replenishment device is used to replenish diamond particles and a water-oil mixture into the grinding fluid;

[0093] The recovery device includes a return tank and a return drive pump, which are used to recover the grinding fluid during the processing and to fully mix the recovered grinding fluid with the existing grinding fluid.

[0094] The stirring device, the drive pump, and the liquid replenishment device are connected by a hose;

[0095] The output end of the drive pump is connected in sequence to a hose and a nozzle, and the nozzle is aligned with the grinding area of ​​the complex thin-walled component to be processed.

[0096] The return tank, the return drive pump, and the stirring device are connected by a flexible hose.

[0097] Baffles are installed in the machine tool processing area to ensure that the mixture does not flow or splash during ultra-precision grinding.

[0098] Specific Implementation Plan Nine: (e.g.) Figure 8 As shown, the fluid replenishment device includes a diamond particle replenishment device and a water-oil mixture replenishment device;

[0099] The fluid replenishment device includes a diamond particle replenishment device and a water-oil mixture replenishment device. The diamond particle replenishment device includes an automatic feeder for periodically replenishing a certain volume of diamond particles to the grinding fluid. The water-oil mixture replenishment device is equipped with a liquid titrator to control the volume of water-oil mixture added. Other aspects of this embodiment are the same as in specific embodiment eight.

[0100] The automatic replenishing machine in this embodiment uses an Evalles timed replenishing device. The water-oil mixture replenishing device includes a reservoir, a liquid titrator, and a hose. The reservoir holds the water-oil mixture, and the output end of the reservoir is connected to the hose, the other end of which extends into the mixing device. The liquid titrator is mounted on the hose and is used to control the volume of water-oil mixture added. This replenishing device enables automatic replenishment of the water-oil grinding fluid containing W3 diamond particles.

[0101] Example 1

[0102] To verify the advantages of the method of the present invention, specific embodiments are used to illustrate the present invention below.

[0103] With a feed rate f of 0.03 mm / min and a single cutting depth a p 0.005mm, grinding wheel spindle speed v sUnder the premise of consistent grinding process parameters such as 71000 rpm, hemispherical harmonic oscillators were ground for 10, 20, 30, and 40 cycles respectively. The effects of a water-oil mixed grinding fluid with a water-to-oil volume ratio of 50:1 and the addition of 40 cm³ of grinding fluid were investigated. 3 The analysis of the surface roughness, roundness, coaxiality, and grinding wheel wear of the hemispherical harmonic oscillator processed with W3 diamond particles in a water-oil mixed grinding fluid of / L is shown in Tables 4 to 7.

[0104] Table 5 shows the roughness comparison results when machining the inner support rod, the root of the outer spherical surface, the root of the inner spherical surface, and the end face of the hemispherical resonator component using different grinding fluids.

[0105] Table 5

[0106]

[0107] Table 6 shows the maximum wear of ball end grinding wheels under the same grinding process parameters for the two grinding fluids.

[0108] Table 6

[0109]

[0110] Based on such Figure 9 The test positions for the hemispherical harmonic oscillator are shown in Table 7. Table 7 shows the roundness values ​​of the four same positions on the outer spherical surface of the hemispherical harmonic oscillator when measured using two different grinding fluids under the aforementioned grinding process parameters.

[0111] Table 7

[0112]

[0113] Based on such Figure 9 The coaxiality test positions of the hemispherical harmonic oscillator are shown in Table 8. Table 8 shows the coaxiality values ​​when the same four positions on the outer spherical surface of the hemispherical harmonic oscillator are measured using two different grinding fluids under the aforementioned grinding process parameters.

[0114] Table 8

[0115]

[0116] From the results of Table 5, it can be seen that, compared with the water-oil mixed grinding fluid, the water-oil mixed grinding fluid added with W3 diamond particles can effectively improve the surface roughness of the ultra-precision grinding of the complex thin-walled component, and the improvement rate is more than 151.17%; according to the results of Table 6, it can be seen that the water-oil mixed grinding fluid added with W3 diamond particles can slow down the wear of the ball head grinding wheel, and the wear amount is reduced by 66.46% in the grinding period; from the results of Table 7, it can be seen that, compared with the water-oil mixed grinding fluid, the water-oil mixed grinding fluid added with W3 diamond particles can effectively improve the roundness of the ultra-precision grinding of the complex thin-walled component, and the improvement rate is more than 95.95%; from the results of Table 8, it can be seen that, compared with the water-oil mixed grinding fluid, the water-oil mixed grinding fluid added with W3 diamond particles can effectively improve the coaxiality of the ultra-precision grinding of the complex thin-walled component, and the improvement rate is more than 33.83%; in addition to the above analysis, it is found that the quality factor of the hemispherical resonator obtained by using the water-oil mixed grinding fluid is about 880W, and the frequency splitting is 0.2Hz, while the quality factor of the hemispherical resonator obtained by using the water-oil mixed grinding fluid added with W3 diamond particles is about 1200W, and the frequency splitting is 0.03Hz. It can be seen that the water-oil mixed grinding fluid added with W3 diamond particles has greater potential in grinding.

[0117] Although the present application discloses as above, the protection scope of the present application is not limited to this. The person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and these changes and modifications will fall within the protection scope of the present application.

Claims

1. A method for ultra-precision grinding of complex thin-walled components based on the addition of W3 diamond particles, characterized in that, The method comprises the following steps: Step 1: build a grinding fluid circulation system; Step 2: prepare water-oil mixed grinding fluid with diamond particles; Step 3: add the prepared grinding fluid into the grinding fluid circulation system for fully stirring, and the stirring time is T; Step 4: deliver the fully stirred grinding fluid to the grinding area of the complex thin-walled component to be processed through a driving pump, and carry out ultra-precision grinding processing; Step 5: recycle the water-oil mixed grinding fluid with diamond particles in the grinding processing, fully mix the recycled grinding fluid with the existing grinding fluid, regularly supplement diamond particles and water-oil mixture into the grinding fluid considering the liquid loss in the processing, and complete the processing; The diamond particles in Step 2 are W3 diamond particles; The volume ratio of W3 diamond particles to water-oil mixture in the water-oil mixed grinding fluid with diamond particles in Step 2 ranges from 3.8% to 5.5%; The calculation method of the stirring time T in Step 3 is as follows: The unit of T is hour; The rotating speed of the driving pump in Step 4 is set to 30 rpm; The W3 diamond particles and the water-oil mixture are supplemented into the grinding fluid in Step five, specifically: W3 diamond particles are supplemented into the grinding fluid at a ratio of 0.45 cm 3 / L every 30 min, and the water-oil mixture is supplemented into the grinding fluid at a ratio of 30 mL / L every 30 min.

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