阅读说明：本技术 一种基于水浴加热辅助的小球头磁流变抛光方法 (Water-bath heating-assisted small ball head magnetorheological polishing method ) 是由 刘赫男 田金川 陈明君 程健 吴春亚 于 2021-09-29 设计创作，主要内容包括：一种基于水浴加热辅助的小球头磁流变抛光方法,它属于研抛加工技术领域,具体涉及一种小球头磁流变抛光方法。本发明的目的是要解决现有小球头磁流变抛光技术加工工件时存在抛光效率较低的问题。方法：一、配置磁流变液；二、将磁流变液倒入搅拌器中；三、装卡被加工工件；四、调整抛光工具头的球心位置；五、编写加工轨迹程序,并导入机床控制软件中,调整将抛光头加工轨迹；六、调整抛光头位置；七、组装磁流变液循环回路；八、将硅胶软管放入恒温水浴锅中；九、设定恒温水浴锅的温度；十、调整恒温水浴锅的设定温度；十一、放置磁流变液挡板,开启抛光工具头主轴和工件主轴；十二、对被加工工件进行抛光。本发明主要用于小球头磁流变抛光。(A small ball head magnetorheological polishing method based on water bath heating assistance belongs to the technical field of polishing processing, and particularly relates to a small ball head magnetorheological polishing method. The invention aims to solve the problem of low polishing efficiency when the existing small ball head magnetorheological polishing technology is used for processing workpieces. The method comprises the following steps: firstly, preparing magnetorheological fluid; secondly, pouring the magnetorheological fluid into a stirrer; thirdly, clamping the processed workpiece; fourthly, adjusting the position of the spherical center of the polishing tool head; fifthly, compiling a machining track program, importing the program into machine tool control software, and adjusting the machining track of the polishing head; sixthly, adjusting the position of the polishing head; seventhly, assembling a magnetorheological fluid circulation loop; eighthly, placing the silica gel hose into a constant-temperature water bath kettle; ninth, setting the temperature of the constant-temperature water bath kettle; tenthly, adjusting the set temperature of the constant-temperature water bath kettle; placing a magnetorheological fluid baffle, and opening a main shaft of the polishing tool head and a main shaft of the workpiece; and twelfth, polishing the workpiece to be processed. The invention is mainly used for the magnetorheological polishing of the small ball head.)

1. A small ball head magnetorheological polishing method based on water bath heating assistance is characterized by comprising the following steps:

firstly, preparing magnetorheological fluid: adding cellulose into hot water of 100 ℃ and uniformly stirring, then adding water of 20 ℃ and normal temperature and uniformly stirring again, then adding cerium oxide polishing powder and uniformly stirring, finally adding carbonyl iron powder and uniformly stirring to obtain magnetorheological fluid; the mass ratio of the cellulose to the hot water at 100 ℃ is 3.5 (480-520); the mass ratio of the cellulose to the water at the normal temperature of 20 ℃ is 3.5 (400-420); the mass ratio of the cellulose to the cerium oxide polishing powder is 3.5 (165-200); the mass ratio of the cellulose to the carbonyl iron powder is 3.5 (2050-2150);

secondly, pouring the magnetorheological fluid into a storage tank of a stirrer, and stirring the magnetorheological fluid before use;

thirdly, clamping the machined workpiece on the main shaft, measuring radial circular runout of the workpiece at different positions by using a dial indicator, and if the runout is greater than 5 microns, re-clamping until the runout is maintained within 5 microns;

fourthly, adjusting the position of the spherical center of the polishing tool head by means of a CCD camera and an amplifying lens to enable the spherical center to be superposed with the rotation center line of the C-axis turntable;

fifthly, compiling a machining track program, importing the program into machine tool control software, and deviating the machining track of the polishing head by 0.1mm in the direction away from the workpiece by using a tool length compensation instruction G43 in the machine tool control software;

sixthly, operating the machine tool to adjust the position of the polishing head so that the polishing head is positioned at the processing starting point;

placing a magnetorheological fluid recovery base below the processed workpiece, sequentially connecting a stirrer, a supply peristaltic pump and a universal bamboo joint pipe spray head by utilizing a silica gel hose according to the flowing direction of the magnetorheological fluid, sequentially connecting the magnetorheological fluid recovery base, the recovery peristaltic pump and the stirrer, and placing the magnetorheological fluid recovery base below the universal bamboo joint pipe spray head to form a closed magnetorheological fluid circulation loop;

eighthly, coiling the middle part of a silica gel hose between a feeding peristaltic pump and a universal bamboo joint pipe spray head, and putting the coiled silica gel hose into a constant-temperature water bath kettle;

adding water into the constant-temperature water bath according to the requirement, setting the temperature of the constant-temperature water bath according to the target temperature of the magnetorheological fluid, and then heating the constant-temperature water bath to the set temperature;

opening an outflow valve of the stirrer after the constant-temperature water bath kettle is heated to a set temperature, starting a peristaltic pump, continuously pumping magnetorheological fluid into a processing area through a silica gel hose, measuring the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head by using a handheld probe type temperature sensor, and if the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head is lower than the target temperature of the magnetorheological fluid, adjusting the set temperature of the constant-temperature water bath kettle to the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head to reach the target temperature of the magnetorheological fluid;

placing magnetorheological fluid baffles around the processed workpiece, starting a main shaft of a polishing tool head to enable a polishing head to rotate at 7000r/min, and starting a main shaft of the workpiece to enable the workpiece to rotate at 90 r/min;

and twelfth, executing the machining track program compiled in the fifth step to polish the machined workpiece.

2. The small ball head magnetorheological finishing method based on the water bath heating assistance as claimed in claim 1, wherein the mass ratio of the cellulose to the hot water at 100 ℃ in the step one is 3.5 (490-510).

3. The small ball head magnetorheological finishing method based on water bath heating assistance as claimed in claim 2, wherein the mass ratio of the cellulose to the hot water at 100 ℃ in the first step is 3.5: 500.

4. The small ball head magnetorheological finishing method based on the water bath heating assistance as claimed in claim 1, wherein the mass ratio of the cellulose to the water at normal temperature of 20 ℃ in the step one is 3.5 (405-415).

5. The small ball head magnetorheological finishing method based on water bath heating assistance as claimed in claim 4, wherein the mass ratio of the cellulose to the water at normal temperature of 20 ℃ in the first step is 3.5: 412.

6. The small ball head magnetorheological polishing method based on water bath heating assistance as claimed in claim 1, wherein the mass ratio of the cellulose to the cerium oxide polishing powder in the step one is 3.5 (166-170).

7. The small ball head magnetorheological polishing method based on water bath heating assistance as claimed in claim 6, wherein the mass ratio of the cellulose to the cerium oxide polishing powder in the first step is 3.5: 168.

8. The small ball head magnetorheological polishing method based on water bath heating assistance as claimed in claim 1, wherein the mass ratio of the cellulose to the carbonyl iron powder in the step one is 3.5 (2080-2120).

9. The small ball head magnetorheological finishing method based on the water bath heating assistance as claimed in claim 9, wherein the mass ratio of the cellulose to the carbonyl iron powder in the first step is 3.5: 2100.

10. The small ball head magnetorheological polishing method based on the water bath heating assistance according to claim 1, wherein the magnetorheological fluid in the second step is stirred for 1 to 1.5 hours at a rotation speed of 550 to 750rpm before use in the first step.

Technical Field

The invention belongs to the technical field of grinding and polishing processing, and particularly relates to a magnetorheological polishing method for a small ball head.

Background

In recent years, with the continuous deepening of scientific research, various new technologies and new theories are continuously applied to the design of new-generation industrial products, small-size complex-structure parts become core devices of some industrial products, the processing quality of the parts directly influences the service performance of the products, generally, the requirements of surface roughness and shape precision of the parts reach the nanometer level and even lower than the submicron level, and the requirements of the precision and the surface quality can be met only by ultra-precise grinding and polishing.

The traditional contact polishing method is difficult to effectively polish the surfaces of parts with complex structures, and the contact polishing can apply pressure to the surfaces of the parts, so that the parts are easy to deform and even break. Therefore, the small-ball head magnetorheological polishing method can be used for carrying out ultra-precise polishing on the small-size complex-structure part. In the magnetorheological polishing process, the polishing tool head made of the permanent magnetic material is not in direct contact with the surface of a workpiece, and a certain gap is reserved between the polishing tool head and the workpiece, so that the magnetorheological fluid can flow through the gap, and the pressure on the surface of the part during polishing can be greatly reduced; by means of the small-size polishing tool head, effective polishing of the surface type position with the small curvature radius in the part with the complex structure can be achieved. The core of the polishing method is magnetorheological fluid which is prepared by raw materials such as non-magnetic base fluid, micron-sized magnetic particles, micron-sized polishing powder, a stabilizing agent and the like according to a specific sequence, and the polishing method is characterized in that the polishing method shows completely different rheological properties under the action of no magnetic field: when no magnetic field acts, the magnetorheological fluid has the characteristics of low-viscosity Newtonian fluid; in the presence of a magnetic field, the magnetorheological fluid is in a high-viscosity solid-like state. The polishing tool head is formed by bonding a head end made of sintered neodymium iron boron made of permanent magnetic materials and a stainless steel rod, when magnetorheological fluid flows through a gap between the polishing tool head and a workpiece, under the action of an external magnetic field from the tool head, magnetic particles in the magnetorheological fluid are coated on the surface of the polishing head within millisecond-level time and form a convergence gap with the surface of the workpiece. In the polishing process, magnetorheological fluid containing abrasive particles flows in the convergence gap to form a layer of liquid film, and the abrasive particles in the liquid film interact with the surface of the workpiece, so that the surface material of the workpiece is removed, and the polishing effect is achieved; after the magnetorheological fluid flows out of the gap, the magnetic field effect disappears, and the magnetorheological fluid is immediately restored to be low-viscosity liquid to normally flow.

In the process of magnetorheological polishing, because the viscosity of magnetorheological fluid is higher, the mobility of the magnetorheological fluid in a polishing gap is lower, the flow rate of a liquid film is lower, the speed and the frequency of the interaction between abrasive particles and the surface of a workpiece are lower, and the improvement of the polishing efficiency is limited.

Disclosure of Invention

The invention aims to solve the problem that the polishing efficiency is low due to the fact that the magnetorheological fluid has high viscosity when a workpiece is processed by using the existing small ball head magnetorheological polishing technology, and the mobility of the magnetorheological fluid in a polishing gap is low, and provides a small ball head magnetorheological polishing method based on water bath heating assistance.

A small ball head magnetorheological polishing method based on water bath heating assistance is specifically completed according to the following steps:

firstly, preparing magnetorheological fluid: adding cellulose into hot water of 100 ℃ and uniformly stirring, then adding water of 20 ℃ and normal temperature and uniformly stirring again, then adding cerium oxide polishing powder and uniformly stirring, finally adding carbonyl iron powder and uniformly stirring to obtain magnetorheological fluid; the mass ratio of the cellulose to the hot water at 100 ℃ is 3.5 (480-520); the mass ratio of the cellulose to the water at the normal temperature of 20 ℃ is 3.5 (400-420); the mass ratio of the cellulose to the cerium oxide polishing powder is 3.5 (165-200); the mass ratio of the cellulose to the carbonyl iron powder is 3.5 (2050-2150);

secondly, pouring the magnetorheological fluid into a storage tank of a stirrer, and stirring the magnetorheological fluid before use;

thirdly, clamping the machined workpiece on the main shaft, measuring radial circular runout of the workpiece at different positions by using a dial indicator, and if the runout is greater than 5 microns, re-clamping until the runout is maintained within 5 microns;

fourthly, adjusting the position of the spherical center of the polishing tool head by means of a CCD camera and an amplifying lens to enable the spherical center to be superposed with the rotation center line of the C-axis turntable;

fifthly, compiling a machining track program, importing the program into machine tool control software, and deviating the machining track of the polishing head by 0.1mm in the direction away from the workpiece by using a tool length compensation instruction G43 in the machine tool control software;

sixthly, operating the machine tool to adjust the position of the polishing head so that the polishing head is positioned at the processing starting point;

placing a magnetorheological fluid recovery base below the processed workpiece, sequentially connecting a stirrer, a supply peristaltic pump and a universal bamboo joint pipe spray head by utilizing a silica gel hose according to the flowing direction of the magnetorheological fluid, sequentially connecting the magnetorheological fluid recovery base, the recovery peristaltic pump and the stirrer, and placing the magnetorheological fluid recovery base below the universal bamboo joint pipe spray head to form a closed magnetorheological fluid circulation loop;

eighthly, coiling the middle part of a silica gel hose between a feeding peristaltic pump and a universal bamboo joint pipe spray head, and putting the coiled silica gel hose into a constant-temperature water bath kettle;

adding water into the constant-temperature water bath according to the requirement, setting the temperature of the constant-temperature water bath according to the target temperature of the magnetorheological fluid, and then heating the constant-temperature water bath to the set temperature;

opening an outflow valve of the stirrer after the constant-temperature water bath kettle is heated to a set temperature, starting a peristaltic pump, continuously pumping magnetorheological fluid into a processing area through a silica gel hose, measuring the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head by using a handheld probe type temperature sensor, and if the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head is lower than the target temperature of the magnetorheological fluid, adjusting the set temperature of the constant-temperature water bath kettle to the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head to reach the target temperature of the magnetorheological fluid;

placing magnetorheological fluid baffles around the processed workpiece, starting a main shaft of a polishing tool head to enable a polishing head to rotate at 7000r/min, and starting a main shaft of the workpiece to enable the workpiece to rotate at 90 r/min;

and twelfth, executing the machining track program compiled in the fifth step to polish the machined workpiece.

The invention has the advantages that:

firstly, the viscosity of the magnetorheological fluid is closely related to the temperature, the higher the temperature is, the lower the viscosity is, the viscosity of the magnetorheological fluid is reduced through water bath heating, the flowing speed of a liquid film is improved, the speed and frequency of interaction of abrasive particles and the surface of a workpiece are increased, and the polishing efficiency is improved.

Secondly, a constant-temperature water bath is adopted, the temperature of the magnetorheological fluid can be adjusted within the temperature range of 20-80 ℃, the viscosity of the magnetorheological fluid is reduced to 1/3-1/10 when the temperature is reduced to room temperature, the fluidity of the magnetorheological fluid can be improved, the magnetorheological fluid replacement in a polishing area is promoted, and the removal rate of the polishing material can be maximally over 0.02mm³And/min, compared with the material removal rate when the magnetorheological fluid is not heated, the polishing efficiency can be improved by more than 120%.

The polishing surface roughness Ra is 5 nm-8 nm when the magnetorheological fluid is not heated, and can reach 3 nm-5 nm by heating the magnetorheological fluid, so that the water bath heating assisted magnetorheological polishing can improve the polishing removal efficiency and further reduce the surface roughness;

the method has no negative influence on the characteristics of the magnetorheological fluid such as stability, sedimentation resistance and the like, and can be used for continuous polishing of workpieces;

the method has certain universality, can be popularized and used for reducing the viscosity of the magnetorheological fluid, improving the fluidity and improving the polishing removal efficiency in the magnetorheological polishing of the small ball head.

Drawings

FIG. 1 is a schematic structural diagram of a four-axis triple-linkage ultra-precise small ball magnetorheological polishing machine tool in embodiment 1;

FIG. 2 is a schematic view showing the structure of a constant temperature water bath in example 1;

FIG. 3 is a schematic flow chart of a magnetorheological fluid cycle in step seven of example 1;

in the figure, a 1-C shaft rotary table, a 2-U shaft connecting frame, a 3-tool main shaft fixing frame, a 4-tool main shaft, a 5-polishing tool, a 6-magnetorheological fluid recovery base, a 7-horizontal workbench, an 8-workpiece main shaft protecting cover, a 9-processed workpiece, a 10-workpiece main shaft, an 11-silica gel hose, a 12-U shaft protecting cover, a 13-U shaft, a 14-constant temperature water bath kettle, a 15-universal bamboo joint pipe nozzle, a 16-recovery peristaltic pump, a 17-stirrer and an 18-supply peristaltic pump are arranged.

Detailed Description

The first embodiment is as follows: the embodiment is a small ball head magnetorheological polishing method based on water bath heating assistance, which is specifically completed according to the following steps:

firstly, preparing magnetorheological fluid: adding cellulose into hot water of 100 ℃ and uniformly stirring, then adding water of 20 ℃ and normal temperature and uniformly stirring again, then adding cerium oxide polishing powder and uniformly stirring, finally adding carbonyl iron powder and uniformly stirring to obtain magnetorheological fluid; the mass ratio of the cellulose to the hot water at 100 ℃ is 3.5 (480-520); the mass ratio of the cellulose to the water at the normal temperature of 20 ℃ is 3.5 (400-420); the mass ratio of the cellulose to the cerium oxide polishing powder is 3.5 (165-200); the mass ratio of the cellulose to the carbonyl iron powder is 3.5 (2050-2150);

secondly, pouring the magnetorheological fluid into a storage tank of a stirrer, and stirring the magnetorheological fluid before use;

thirdly, clamping the machined workpiece on the main shaft, measuring radial circular runout of the workpiece at different positions by using a dial indicator, and if the runout is greater than 5 microns, re-clamping until the runout is maintained within 5 microns;

fourthly, adjusting the position of the spherical center of the polishing tool head by means of a CCD camera and an amplifying lens to enable the spherical center to be superposed with the rotation center line of the C-axis turntable;

fifthly, compiling a machining track program, importing the program into machine tool control software, and deviating the machining track of the polishing head by 0.1mm in the direction away from the workpiece by using a tool length compensation instruction G43 in the machine tool control software;

sixthly, operating the machine tool to adjust the position of the polishing head so that the polishing head is positioned at the processing starting point;

placing a magnetorheological fluid recovery base below the processed workpiece, sequentially connecting a stirrer, a supply peristaltic pump and a universal bamboo joint pipe spray head by utilizing a silica gel hose according to the flowing direction of the magnetorheological fluid, sequentially connecting the magnetorheological fluid recovery base, the recovery peristaltic pump and the stirrer, and placing the magnetorheological fluid recovery base below the universal bamboo joint pipe spray head to form a closed magnetorheological fluid circulation loop;

eighthly, coiling the middle part of a silica gel hose between a feeding peristaltic pump and a universal bamboo joint pipe spray head, and putting the coiled silica gel hose into a constant-temperature water bath kettle;

adding water into the constant-temperature water bath according to the requirement, setting the temperature of the constant-temperature water bath according to the target temperature of the magnetorheological fluid, and then heating the constant-temperature water bath to the set temperature;

opening an outflow valve of the stirrer after the constant-temperature water bath kettle is heated to a set temperature, starting a peristaltic pump, continuously pumping magnetorheological fluid into a processing area through a silica gel hose, measuring the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head by using a handheld probe type temperature sensor, and if the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head is lower than the target temperature of the magnetorheological fluid, adjusting the set temperature of the constant-temperature water bath kettle to the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head to reach the target temperature of the magnetorheological fluid;

placing magnetorheological fluid baffles around the processed workpiece, starting a main shaft of a polishing tool head to enable a polishing head to rotate at 7000r/min, and starting a main shaft of the workpiece to enable the workpiece to rotate at 90 r/min;

and twelfth, executing the machining track program compiled in the fifth step to polish the machined workpiece.

The second embodiment is as follows: the present embodiment differs from the first embodiment in that: in the first step, the mass ratio of the cellulose to the hot water at 100 ℃ is 3.5 (490-510). The rest is the same as the first embodiment.

The third concrete implementation mode: the present embodiment differs from the first or second embodiment in that: the mass ratio of the cellulose to the hot water at 100 ℃ in the first step is 3.5: 500. The rest is the same as the first embodiment.

The fourth concrete implementation mode: the difference between this embodiment and one of the first to third embodiments is as follows: in the first step, the mass ratio of the cellulose to the water at the normal temperature of 20 ℃ is 3.5 (405-415). The others are the same as the first to third embodiments.

The fifth concrete implementation mode: the difference between this embodiment and one of the first to fourth embodiments is: the mass ratio of the cellulose to the water at the normal temperature of 20 ℃ in the step one is 3.5: 412. The rest is the same as the first to fourth embodiments.

The sixth specific implementation mode: the difference between this embodiment and one of the first to fifth embodiments is as follows: in the first step, the mass ratio of the cellulose to the cerium oxide polishing powder is 3.5 (166-170). The rest is the same as the first to fifth embodiments.

The seventh embodiment: the difference between this embodiment and one of the first to sixth embodiments is: in the first step, the mass ratio of the cellulose to the cerium oxide polishing powder is 3.5: 168. The rest is the same as the first to sixth embodiments.

The specific implementation mode is eight: the difference between this embodiment and one of the first to seventh embodiments is: in the first step, the mass ratio of the cellulose to the carbonyl iron powder is 3.5 (2080-2120). The rest is the same as the first to seventh embodiments.

The specific implementation method nine: the difference between this embodiment and the first to eighth embodiments is: the mass ratio of the cellulose to the carbonyl iron powder in the first step is 3.5: 2100. The others are the same as the first to eighth embodiments.

The detailed implementation mode is ten: the difference between this embodiment and one of the first to ninth embodiments is as follows: and stirring the magnetorheological fluid in the step two in the step one for 1 to 1.5 hours at the rotating speed of 550 to 750rpm before use. The rest is the same as the first to ninth embodiments.

The invention is not limited to the above embodiments, and one or a combination of several embodiments may also achieve the object of the invention.

The following tests are adopted to verify the effect of the invention:

example 1: a small ball head magnetorheological polishing method based on water bath heating assistance adopts a four-axis triple-linkage ultra-precise small ball head magnetorheological polishing machine tool and is provided with a constant-temperature water bath kettle, and the method is specifically completed according to the following steps:

firstly, preparing magnetorheological fluid: adding 3.5g of cellulose into 500g of hot water at 100 ℃, uniformly stirring, then adding 412g of water at 20 ℃ and uniformly stirring again, then adding 168g of cerium oxide polishing powder, uniformly stirring, finally adding 2100g of carbonyl iron powder, and uniformly stirring to obtain magnetorheological fluid;

secondly, pouring the magnetorheological fluid into a storage tank of a stirrer, and stirring the magnetorheological fluid for 1.2 hours at the rotating speed of 650rpm before use;

thirdly, clamping the machined workpiece on the main shaft, measuring radial circular runout of the workpiece at different positions by using a dial indicator, and if the runout is greater than 5 microns, re-clamping until the runout is maintained within 5 microns;

fourthly, adjusting the position of the spherical center of the polishing tool head by means of a CCD camera and an amplifying lens to enable the spherical center to be superposed with the rotation center line of the C-axis turntable;

fifthly, compiling a machining track program, importing the program into machine tool control software, and deviating the machining track of the polishing head by 0.1mm in the direction away from the workpiece by using a tool length compensation instruction G43 in the machine tool control software;

sixthly, operating the machine tool to adjust the position of the polishing head so that the polishing head is positioned at the processing starting point;

placing a magnetorheological fluid recovery base below the processed workpiece, sequentially connecting a stirrer, a supply peristaltic pump and a universal bamboo joint pipe spray head by utilizing a silica gel hose according to the flowing direction of the magnetorheological fluid, sequentially connecting the magnetorheological fluid recovery base, the recovery peristaltic pump and the stirrer, and placing the magnetorheological fluid recovery base below the universal bamboo joint pipe spray head to form a closed magnetorheological fluid circulation loop;

eighthly, coiling the middle part of a silica gel hose between a feeding peristaltic pump and a universal bamboo joint pipe spray head, and putting the coiled silica gel hose into a constant-temperature water bath kettle;

adding water into the constant-temperature water bath according to the requirement, setting the temperature of the constant-temperature water bath according to the target temperature of the magnetorheological fluid, and then heating the constant-temperature water bath to the set temperature;

opening an outflow valve of the stirrer after the constant-temperature water bath kettle is heated to a set temperature, starting a peristaltic pump, continuously pumping magnetorheological fluid into a processing area through a silica gel hose, measuring the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head by using a handheld probe type temperature sensor, and if the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head is lower than the target temperature of the magnetorheological fluid, adjusting the set temperature of the constant-temperature water bath kettle to the temperature of the magnetorheological fluid at the outlet position of the universal bamboo joint pipe spray head to reach the target temperature of the magnetorheological fluid;

placing magnetorheological fluid baffles around the processed workpiece, starting a main shaft of a polishing tool head to enable a polishing head to rotate at 7000r/min, and starting a main shaft of the workpiece to enable the workpiece to rotate at 90 r/min;

and twelfth, executing the machining track program compiled in the fifth step to polish the machined workpiece.

Comparative example 1: comparison without constant temperature water bath:

firstly, preparing magnetorheological fluid: adding 3.5g of cellulose into 500g of hot water at 100 ℃, uniformly stirring, then adding 412g of water at 20 ℃ and uniformly stirring again, then adding 168g of cerium oxide polishing powder, uniformly stirring, finally adding 2100g of carbonyl iron powder, and uniformly stirring to obtain magnetorheological fluid;

secondly, pouring the magnetorheological fluid into a storage tank of a stirrer, and stirring the magnetorheological fluid for 1.2 hours at the rotating speed of 650rpm before use;

thirdly, clamping the machined workpiece on the main shaft, measuring radial circular runout of the workpiece at different positions by using a dial indicator, and if the runout is greater than 5 microns, re-clamping until the runout is maintained within 5 microns;

fourthly, adjusting the position of the spherical center of the polishing tool head by means of a CCD camera and an amplifying lens to enable the spherical center to be superposed with the rotation center line of the C-axis turntable;

fifthly, compiling a machining track program, importing the program into machine tool control software, and deviating the machining track of the polishing head by 0.1mm in the direction away from the workpiece by using a tool length compensation instruction G43 in the machine tool control software;

sixthly, operating the machine tool to adjust the position of the polishing head so that the polishing head is positioned at the processing starting point;

placing a magnetorheological fluid recovery base below the processed workpiece, sequentially connecting a stirrer, a supply peristaltic pump and a universal bamboo joint pipe spray head by utilizing a silica gel hose according to the flowing direction of the magnetorheological fluid, sequentially connecting the magnetorheological fluid recovery base, the recovery peristaltic pump and the stirrer, and placing the magnetorheological fluid recovery base below the universal bamboo joint pipe spray head to form a closed magnetorheological fluid circulation loop;

eighthly, placing magnetorheological fluid baffles around the processed workpiece, starting a main shaft of a polishing tool head to enable a polishing head to rotate at 7000r/min, and starting a main shaft of the workpiece to enable the workpiece to rotate at 90 r/min;

and ninthly, executing the machining track program compiled in the step five to polish the machined workpiece.

The removal rates of the polishing materials of example 1 and comparative example 1 were statistically calculated, respectively, and the roughness of the polished surface of the machined workpiece after polishing of example 1 and comparative example 1 was examined, as shown in table 1.

TABLE 1

	Removal rate of polishing material (mm)3/min)	Polishing surface roughness Ra (nm)
			Example 1	0.02	4.1
Comparative example 1	0.01	6.1

As can be seen from Table 1, the removal rate of the polishing material reaches 0.02mm at most by using the small ball head magnetorheological polishing technology assisted by water bath heating³Min, the roughness Ra of the polished surface can reach 4.1nm, and the removal rate of the polishing material is only 0.01mm in the existing common small ball head magnetorheological polishing technology (comparative example 1)³Min, polished surface roughness Ra 6.1 nm. And the polishing efficiency of the polishing method of example 1 is improved by more than 120% compared with that of comparative example 1 by calculation of the polishing efficiency.