A magnetic refrigeration system for cryogenic cutting tools and a cryogenic cutting method

Abstract

The present invention discloses a magnetic refrigeration system for a cryogenic cutting tool and a cryogenic cutting method; the magnetic refrigeration system for the cryogenic cutting tool includes a tool, a magnetic refrigeration device, and a fluid transmission device. The magnetic refrigeration device includes a magnetic refrigeration container and an electromagnetic coil. A hollow iron core is coaxially sleeved outside the magnetic refrigeration container; the electromagnetic coil is wound outside the hollow iron core. An inner cavity and an outer cavity are provided in the magnetic refrigeration container. A magnetic nanofluid is stored in the inner cavity; a heat transfer medium is stored in the outer cavity. A cooling flow channel is arranged inside the tool. A separable blade is installed on the tool; the cooling flow channel passes through a position close to the separable blade. The present invention utilizes the characteristic that the refrigeration of cryogenic cutting operation is intermittent refrigeration, and when retracting the tool, the temperature of the magnetic nanofluid as the refrigeration working medium is further reduced compared with the heat transfer medium through magnetic refrigeration; thereby overcoming the problem that the direct cooling of the tool by the conventional heat transfer medium cannot meet the requirements of cryogenic cutting operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of tool cooling, and particularly relates to a magnetic refrigeration system for cryogenic cutting tools and a cryogenic cutting method. Background Art

[0002] Cryogenic machining is a new type of special machining process, mainly applied to the cutting of difficult-to-machine metals (such as titanium alloys, superalloys, etc.), fiber-reinforced composites (such as carbon fiber composites, etc.), and high molecular polymers (such as polytetrafluoroethylene, etc.). Due to their own machining characteristics, a large amount of cutting heat is generated during the cutting process of these materials, seriously affecting the service life of the tool and reducing the machining efficiency. Cryogenic machining technology cools the workpiece, tool, and cutting area to a low temperature through a cryogenic medium. This technology can not only reduce tool wear and improve tool life, but also significantly improve machining accuracy and workpiece surface quality. In addition, during the cutting, sawing, and drilling of biological products such as teeth and bones, temperature control is very important. Cryogenic machining helps to maintain cell activity, maintain the integrity of tissue structure, and prevent heat loss.

[0003] According to the cooling temperature, cryogenic cutting is mainly divided into three types: cutting below room temperature (4°C - 6°C), cutting below zero (0°C - -30°C), and ultra-low temperature cutting (less than -50°C). Currently, cryogenic machining technologies mainly include cryogenic air cooling, liquid nitrogen cooling, and electronic refrigeration, etc. However, when machining some materials with high requirements for the cleanliness of the machining environment, cryogenic gases or liquids are often not allowed to be added to the cutting area. In addition, the existing liquid cooling and heat dissipation methods are greatly affected by the environment and are difficult to reduce to a sufficiently low temperature. The general price of cryogenic media is expensive, resulting in a significant increase in machining costs, which is also a reason for the limited application of cryogenic machining technology. Therefore, it is very important to find a tool cooling technology that can efficiently cool and is green and pollution-free.

[0004] Magnetic refrigeration is a new type of refrigeration technology based on the magnetocaloric effect. The magnetocaloric effect refers to that when a magnetic material is in an external magnetic field, it will release heat or absorb heat to the external environment when the magnetic field increases or decreases. By constructing a heat cycle, the refrigeration effect can be achieved. Magnetic refrigeration technology is more efficient, more energy-saving, and noiseless than traditional refrigeration technology. Moreover, non-toxic magnetic materials can be selected, which is an environmentally friendly refrigeration technology. However, during the process of magnetic refrigeration, there are stages of isothermal magnetization by applying a magnetic field and demagnetization for cooling, and refrigeration cannot be carried out during this stage; this makes it difficult for magnetic refrigeration to be used in common heat dissipation conditions. Summary of the Invention

[0005] The purpose of the present invention is to provide a magnetic refrigeration system for cryogenic cutting tools and a cryogenic cutting method.

[0006] The present invention provides a magnetic refrigeration system for a cryogenic cutting tool, which includes a tool, a magnetic refrigeration device, and a fluid transmission device. The magnetic refrigeration device includes a magnetic refrigeration container and an electromagnetic coil. A hollow iron core is coaxially sleeved outside the magnetic refrigeration container; the electromagnetic coil is wound outside the hollow iron core. The magnetic refrigeration container is provided with an inner cavity and an outer cavity; the inner cavity is arranged inside the outer cavity, and the inner cavity and the outer cavity are independent of each other. The inner cavity stores magnetic nanofluid; the outer cavity stores a heat transfer medium. A cooling flow channel is arranged inside the tool. A detachable blade is installed on the tool; the cooling flow channel passes through a position close to the detachable blade.

[0007] The fluid transmission device includes a flow regulating valve, a hydraulic pump, a check valve, and an adiabatic flow pipe. The inner cavity of the magnetic refrigeration container, the flow regulating valve, the hydraulic pump, the check valve, and the cooling flow channel in the tool are sequentially connected by the adiabatic flow pipe to form a liquid cooling circulation loop.

[0008] During the working process, when the electromagnetic coil is energized, the magnetic nanofluid releases heat and transfers the heat to the heat transfer medium; when the tool needs to be cooled, the electromagnetic coil is de-energized, and the temperature of the magnetic nanofluid decreases; the fluid transmission device transports the magnetic nanofluid to the cooling flow channel in the tool to cool the detachable blade.

[0009] Preferably, a plurality of magnetic refrigeration units are arranged side by side in the magnetic refrigeration container; branch on-off valves are arranged at the liquid inlet or outlet of the inner cavity of each magnetic refrigeration unit; different temperature heat transfer media are stored in the outer cavities of three magnetic refrigeration units, so that the temperatures of the magnetic nanofluids output from the inner cavities of the three magnetic refrigeration units are different; during the working process, according to the temperature requirement of the cutting process, the branch on-off valve corresponding to one of the magnetic refrigeration units is opened, and the branch on-off valves corresponding to the remaining magnetic refrigeration units are closed.

[0010] Preferably, both the magnetic refrigeration device and the control module are installed on the workbench. A positioning boss is provided at the bottom end of the magnetic refrigeration container; the positioning boss of the magnetic refrigeration container is fixed in the positioning groove on the workbench.

[0011] Preferably, the magnetic refrigeration system for the cryogenic cutting tool further includes a control module; the electromagnetic coil is connected to the control module; the control module changes the magnitude of the current passed through the electromagnetic coil.

[0012] Preferably, both the input port and the output port of the cooling flow channel are located at the tail end of the tool.

[0013] Preferably, a heat conducting rod is embedded inside the head end of the tool. The heat conducting rod is aligned with the detachable blade on the tool. Thermal grease is filled between the detachable blade and the end of the heat conducting rod. The cooling flow channel bypasses the heat conducting rod.

[0014] Preferably, the portion of the heat conduction rod bypassed by the cooling channel is helical and wound around the heat conduction rod.

[0015] Preferably, a temperature sensor is installed on the tool near the detachable blade.

[0016] Preferably, the magnetic nanofluid is a nanofluid made of multiple of ammonium iron alum, potassium chrome alum and cerium magnesium nitrate nanoparticles;

[0017] Preferably, the material of the partition layer between the inner cavity and the outer cavity of the magnetic refrigeration container is copper.

[0018] Preferably, the heat of the heat transfer medium in the outer cavity of the magnetic refrigeration container is released through an external heat exchange system.

[0019] A cryogenic cutting method uses the aforementioned cryogenic cutting tool magnetic refrigeration system; the method includes the following steps:

[0020] Step 1: The electromagnetic coil is energized and the current is gradually increased. The heat released by the magnetic nanofluid is absorbed by the heat transfer medium. The magnetic nanofluid is magnetized and releases heat; the heat released by the magnetic nanofluid is absorbed by the heat transfer medium.

[0021] Step 2: Before the cutting process, the electromagnetic coil is powered off and the magnetic field disappears. The magnetic nanofluid absorbs the magnetization heat, so that the temperature of the magnetic nanofluid is reduced to below the temperature of the heat transfer medium.

[0022] Step 3: The tool cuts the workpiece; the hydraulic pump transports the magnetic nanofluid in the magnetic refrigeration container to the cooling channel in the tool to cool the tool. During the cutting feed gap, Steps 1 and 2 are repeatedly executed to reduce the temperature of the magnetic nanofluid in the inner cavity of the magnetic refrigeration container.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention utilizes the characteristic that the refrigeration of cryogenic cutting operation is intermittent refrigeration (retracting the tool is required between two cutting feeds). When retracting the tool, the temperature of the magnetic nanofluid as the refrigeration working medium is further reduced compared to the heat transfer medium through magnetic refrigeration, realizing the application of magnetic refrigeration in tool heat dissipation; thus overcoming the problem that the direct cooling of the tool by conventional heat transfer media cannot meet the requirements of cryogenic cutting operations.

[0025] 2. The present invention realizes the isothermal magnetization of the magnetic nanofluid by setting the inner and outer cavities in the magnetic refrigeration container, maximizing the refrigeration performance of the magnetic nanofluid, and the recycling of the magnetic nanofluid also reduces resource consumption.

[0026] 3. The present invention monitors the temperature of the magnetic nanofluid at the tool tip in real time through a temperature sensor, and adjusts the magnetocaloric effect by changing the magnetic field strength and the flow rate of the magnetic nanofluid, so as to achieve low-latency control of the tool processing temperature and prevent the tool from being excessively worn due to excessive temperature, thereby reducing the service life of the tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0028] Figure 2 It is an internal structure diagram of the magnetocaloric container in the present invention.

[0029] Figure 3 It is a schematic diagram of the structure of the tool in the present invention.

[0030] Figure 4 It is a temperature control flow chart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be further described below with reference to the accompanying drawings.

[0032] As Figure 1 shown, a magnetocaloric refrigeration system for a cryogenic cutting tool includes a tool 1, a workbench 5, a magnetocaloric refrigeration device, a fluid transmission device, and a control module 8. The magnetocaloric refrigeration device and the control module 8 are both installed on the workbench 5. The magnetocaloric refrigeration device includes a magnetocaloric container 2 and an electromagnetic coil 3. The bottom end of the magnetocaloric container 2 is provided with a positioning boss; the positioning boss of the magnetocaloric container 2 is fixed in the positioning groove on the workbench 5. A hollow iron core is coaxially sleeved outside the magnetocaloric container 2; the electromagnetic coil 3 is wound outside the hollow iron core. The electromagnetic coil 3 is connected to the control module 8; the control module 8 adjusts the magnetic field strength generated by the electromagnetic coil 3 by changing the magnitude of the current passing through the electromagnetic coil 3, thereby changing the magnetocaloric effect. The magnetocaloric refrigeration device is used to lower the temperature of the magnetic nanofluid in the magnetocaloric container 2 to obtain a magnetic nanofluid with a temperature lower than the heat transfer medium.

[0033] As Figure 3 shown, a cooling channel 13 is provided inside the tool 1. The input port and the output port of the cooling channel 13 are both located at the tail end of the tool 1. A heat conducting rod 14 is embedded inside the head end of the tool 1. The heat conducting rod 14 is aligned with the separable blade 11 on the tool 1. A heat conducting silicone grease 12 is filled between the separable blade 11 and the end of the heat conducting rod to accelerate the heat conduction and cooling of the tool cutting area. The cooling channel 13 bypasses the heat conducting rod. In some preferred embodiments, the part of the heat conducting rod bypassed by the cooling channel 13 is spiral and wound around the heat conducting rod, so that the magnetic nanofluid with reduced temperature stays at the tool tip for a longer time, fully cools the tool tip area, and improves the heat exchange efficiency.

[0034] The fluid transmission device is installed on the workbench 5 and includes a flow regulating valve 4, a hydraulic pump 6, a check valve 7, and an adiabatic flow pipe. The inner cavity 23 of the magnetic refrigeration container 2, the flow regulating valve 4, the hydraulic pump 6, the check valve 7, and the cooling flow channel 13 in the tool 1 are sequentially connected through the adiabatic flow pipe to form a liquid cooling circulation loop.

[0035] As Figure 2 shown, the magnetic refrigeration container 2 includes three magnetic refrigeration units arranged side by side in an adiabatic container; a heat insulation layer is provided between adjacent magnetic refrigeration units. Each magnetic refrigeration unit includes a branch on-off valve 21, an outer cavity 22, and an inner cavity 23; the inner cavity 23 is arranged inside the outer cavity 22, and the inner cavity 23 and the outer cavity 22 are not connected to each other. Magnetic nanofluids serving as refrigerants are stored in all three inner cavities 23; heat transfer media at different temperatures are respectively stored in the three outer cavities 22; the function of the heat transfer media is to receive the heat conducted by the magnetic nanofluids, so that the temperature of the magnetic nanofluids remains basically unchanged before and after the magnetic field is applied, realizing isothermal magnetization. The branch on-off valve 21 is connected to the liquid inlet of the inner cavity 23.

[0036] The heat transfer media are used to absorb the heat in the magnetic nanofluids; three heat transfer media with different temperatures are respectively stored in the three outer cavities 22 to obtain magnetic nanofluids at different temperatures, so as to facilitate low-temperature cutting with different temperature requirements. By controlling the opening and closing of the three branch on-off valves 21, the inner cavity 23 in any one of the magnetic refrigeration units can be selected to be connected to the liquid cooling circulation loop, thereby taking advantage of the different basic temperatures provided by different heat transfer media to output magnetic nanofluids at different temperatures.

[0037] An input port and an output port are provided on the magnetic refrigeration container 2. The input port of the magnetic refrigeration container 2 is connected to the branch on-off valve 21 in the three magnetic refrigeration units through a bifurcated flow channel. The liquid outlets of the inner cavities 23 in the three magnetic refrigeration units are connected to the output port of the magnetic refrigeration container 2 through a converging flow channel.

[0038] In some embodiments, the temperature of the heat transfer media is maintained within a certain range by regularly or irregularly replacing and supplementing the heat transfer media. Ice-water mixture (0 °C), liquid carbon dioxide (-37 °C), and liquid nitrogen (-196 °C) are respectively stored in the three outer cavities; for heat transfer media that absorb heat and gasify (such as liquid carbon dioxide and liquid nitrogen), exhaust valves are provided at the tops of the corresponding outer cavities to facilitate pressure relief.

[0039] In some embodiments, each outer cavity is arranged in an annular container; the annular container can be disassembled and replaced from the magnetic refrigeration container 2, and thus the heat transfer media can be quickly replaced or supplemented by replacing the annular container.

[0040] In some embodiments, the heat conducted to the heat transfer medium is released through an external heat exchange system. Based on this, the three outer cavities 22 are respectively connected to heat exchange systems of three different heat transfer media, so as to release the heat of the heat transfer medium to the outside world, and keep the temperature of the heat transfer medium in each outer cavity constant. Freon, ammonia, and propane are stored in the three outer cavities respectively.

[0041] During the cutting process, under the action of the hydraulic pump, the magnetic nanofluid is unidirectionally input into the internal cooling channel 13 of the cutting tool 1 to realize tool refrigeration. The magnetic nanofluid output from the internal cooling channel 13 of the tool will flow back to the magnetic refrigeration container and wait for a new round of refrigeration process.

[0042] The temperature sensor 9 is installed on the cutting tool 1 near the tool tip, and the detection part of the temperature sensor 9 extends into the cooling channel 13. The temperature sensor 9 is used to monitor the temperature of the magnetic nanofluid in the tool tip area in real time. The temperature signal transmission line is connected to the control module 8, and the real-time temperature is displayed on the display of the control module. If the temperature exceeds the preset range, the operator adjusts the flow rate or pauses the machining and performs magnetic refrigeration again to enhance the magnetic refrigeration effect and prevent excessive tool wear.

[0043] The process of magnetic refrigeration is as follows: after an electric current is passed through the electromagnetic coil, a directional magnetic field will be generated inside the coil. The magnetic nanofluid in the inner cavity of the magnetic refrigeration container will undergo a magnetocaloric effect under the action of the magnetic field, and the magnetic nanofluid will generate magnetization heat. The heat is transferred to the heat transfer medium, so that the temperature of the magnetic nanofluid continues to be close to the temperature of the heat transfer medium, realizing isothermal magnetization. When tool cooling is required, the electromagnetic coil is powered off and the external magnetic field disappears. Under adiabatic conditions, the magnetic nanofluid needs to absorb a large amount of magnetization heat, so that the temperature of the magnetic nanofluid is reduced to be lower than the temperature of the heat transfer medium; at this time, using the magnetic nanofluid helps to improve the cooling effect of the tool. The heat conducted to the heat transfer medium is released through an external heat exchange system, or the temperature of the heat transfer medium is maintained within a certain range by replacing the heat transfer medium.

[0044] In some embodiments, the magnetic refrigeration container is obtained by modifying a Dewar flask to ensure that it is always in an adiabatic environment during the magnetic refrigeration cycle.

[0045] In some embodiments, the magnetic nanofluid is a nanofluid made of nanoparticles of multiple paramagnetic materials; the paramagnetic materials include ferric ammonium alum, potassium chrome alum, and cerium magnesium nitrate, so that the magnetic phase transition temperature range of the magnetic nanofluid is as large as possible.

[0046] In some embodiments, the partition layer between the inner cavity and the outer cavity of the magnetic refrigeration container is made of copper metal to improve the heat exchange ability between the magnetic nanofluid and the heat transfer medium.

[0047] In some embodiments, the magnetic nanofluid is prepared by a two-step method using magnetic nanoparticles, a base liquid, and a surfactant. During the preparation process, water bath heating and ultrasonic vibration are used to increase the dispersion of the nanoparticles in the liquid and improve its stability.

[0048] In some embodiments, the material of the adiabatic flow tube is polyurethane foam.

[0049] As Figure 4 shown, the working process of the magnetic refrigeration system for the cryogenic cutting tool is as follows:

[0050] Step 1: Load the magnetic nanofluid into the inner cavity of the magnetic refrigeration container 2. After a period of time, make the temperature of the magnetic nanofluid the same as the temperature of the heat transfer medium in the outer cavity of the magnetic refrigeration container 2.

[0051] Step 2: The control module 8 controls the electromagnetic coil 3 to be energized and gradually increases the current. The heat released by the magnetic nanofluid is absorbed by the heat transfer medium, causing the magnetic nanofluid to undergo an isothermal magnetization process (i.e., the temperature of the magnetic nanofluid remains basically constant during the magnetization process). After a period of time, the control module 8 controls the electromagnetic coil 3 to be de-energized, and the magnetic field disappears. The magnetic nanofluid absorbs a large amount of magnetization heat, causing the temperature of the magnetic nanofluid to further decrease compared to the temperature of the heat transfer medium.

[0052]

[0053]

[0054]

[0055] where ΔT represents the temperature decrease, T is the initial temperature, ΔS is the magnetic entropy change, Cp is the specific heat capacity of the substance. μ 0 is the magnetic permeability constant in vacuum, H is the magnetic field strength, M is the magnetic polarization intensity, and C is the Curie constant.

[0056] Step 3: The tool 1 cuts the workpiece, generating a large amount of cutting heat and increasing the tool temperature. The control module 8 controls the hydraulic pump 6 to start, and conveys the magnetic nanofluid whose temperature has been reduced in Step 2 to the cooling flow channel 13 in the tool 1 to cool the tool, realizing cryogenic cutting processing. The magnetic nanofluid is adjusted according to the temperature measured by the temperature sensor. During the interval between two cutting feeds, Step 2 is repeated to reduce the temperature of the magnetic nanofluid in the inner cavity of the magnetic refrigeration container 2 to ensure the cooling effect during tool cutting. The temperature of the heat transfer medium is maintained within a preset range through an external heat exchange system or by replacing it irregularly.

Claims

1. A magnetic refrigeration system for a cryogenic cutting tool, Characterized in that: It includes a cutting tool (1), a magnetic refrigeration device, a fluid transmission device, and a control module (8); the magnetic refrigeration device includes a magnetic refrigeration container (2) and an electromagnetic coil (3); a hollow iron core is coaxially sleeved outside the magnetic refrigeration container (2); the electromagnetic coil (3) is wound outside the hollow iron core; a plurality of magnetic refrigeration units are provided in the magnetic refrigeration container (2); the magnetic refrigeration unit includes an inner cavity (23) and an outer cavity (22); the inner cavity (23) is arranged inside the outer cavity (22), and the inner cavity (23) is independent of the outer cavity (22); a magnetic nanofluid is stored in the inner cavity (23); a heat transfer medium is stored in the outer cavity (22); a cooling flow channel (13) is arranged inside the cutting tool (1); a detachable blade (11) is installed on the cutting tool (1); the cooling flow channel (13) passes through a position close to the detachable blade (11). The fluid transmission device includes a flow regulating valve (4), a hydraulic pump (6), a check valve (7), and an adiabatic flow pipe; the inner cavity (23) of the magnetic refrigeration container (2), the flow regulating valve (4), the hydraulic pump (6), the check valve (7), and the cooling flow channel (13) inside the cutting tool (1) are sequentially connected through the adiabatic flow pipe to form a liquid cooling circulation loop. During the working process, when the electromagnetic coil is energized, the magnetic nanofluid releases heat and transfers the heat to the heat transfer medium; when the cutting tool needs to be cooled, the electromagnetic coil is de-energized, and the temperature of the magnetic nanofluid decreases; the fluid transmission device transports the magnetic nanofluid to the cooling flow channel (13) inside the cutting tool (1) to cool the detachable blade (11). A plurality of magnetic refrigeration units are arranged side by side in the magnetic refrigeration container (2); a branch on-off valve (21) is arranged at the liquid inlet or outlet of the inner cavity (23) of each magnetic refrigeration unit; heat transfer media with different temperatures are stored in the outer cavities (22) of three magnetic refrigeration units, so that the temperatures of the magnetic nanofluids output from the inner cavities of the three magnetic refrigeration units are different; during the working process, according to the temperature requirements of the cutting process, the branch on-off valve (21) corresponding to one of the magnetic refrigeration units is opened, and the branch on-off valves (21) corresponding to the remaining magnetic refrigeration units are closed. The electromagnetic coil (3) is connected to the control module (8); the control module (8) adjusts the magnetic field strength generated by the electromagnetic coil (3) by changing the magnitude of the current passing through the electromagnetic coil (3), thereby changing the magnetic refrigeration effect.

2. A magnetic refrigeration system for a cryogenic cutting tool according to claim 1, Characterized in that: The magnetic refrigeration device and the control module (8) are both installed on the workbench (5); a positioning boss is provided at the bottom end of the magnetic refrigeration container (2); the positioning boss of the magnetic refrigeration container (2) is fixed in the positioning groove on the workbench (5).

3. A magnetic refrigeration system for a cryogenic cutting tool according to claim 1, Characterized in that: The input port and the output port of the cooling channel (13) are both located at the tail end of the cutting tool (1); a heat conducting rod (14) is embedded inside the head end of the cutting tool (1); the heat conducting rod (14) is aligned with the separable blade (11) on the cutting tool (1); a heat conducting silicone grease (12) is filled between the separable blade (11) and the end of the heat conducting rod; the cooling channel (13) bypasses the heat conducting rod; the part of the heat conducting rod bypassed by the cooling channel (13) is spiral and wound around the heat conducting rod.

4. A magnetic refrigeration system for a cryogenic cutting tool according to claim 1, characterized in that: a temperature sensor (9) is installed at a position on the cutting tool (1) close to the separable blade (11).

5. A magnetic refrigeration system for a cryogenic cutting tool according to claim 1, characterized in that: the magnetic nanofluid is a nanofluid made of multiple of ammonium iron alum, potassium chrome alum and cerium magnesium nitrate nanoparticles.

6. A magnetic refrigeration system for a cryogenic cutting tool according to claim 1, characterized in that: the material of the partition layer between the inner cavity and the outer cavity of the magnetic refrigeration container is copper.

7. A magnetic refrigeration system for a cryogenic cutting tool according to claim 1, characterized in that: the heat of the heat transfer medium in the outer cavity of the magnetic refrigeration container is released through an external heat exchange system.

8. A cryogenic cutting method, characterized in that: using a magnetic refrigeration system for a cryogenic cutting tool as described in claim 1; the method includes the following steps: Step 1: The electromagnetic coil (3) is energized and the current is gradually increased. The heat released by the magnetic nanofluid is absorbed by the heat transfer medium, and the magnetic nanofluid is magnetized and releases heat; the heat released by the magnetic nanofluid is absorbed by the heat transfer medium; Step 2: Before the cutting process, the electromagnetic coil (3) is de-energized, the magnetic field disappears, and the magnetic nanofluid absorbs the magnetization heat, so that the temperature of the magnetic nanofluid is reduced to be lower than the temperature of the heat transfer medium; Step 3: The cutting tool (1) cuts the workpiece; the hydraulic pump (6) transports the magnetic nanofluid in the magnetic refrigeration container (2) into the cooling channel (13) inside the cutting tool (1) to cool the cutting tool; during the gap of the cutting feed, steps 1 and 2 are repeatedly executed to reduce the temperature of the magnetic nanofluid in the inner cavity of the magnetic refrigeration container (2).

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