Cutting fluid and application, cutting fluid circulation system

Abstract

The application provides a cutting fluid and application and a cutting fluid circulation system. The cutting fluid comprises: an extreme pressure agent, a lubricant, a coolant, a defoaming agent, a corrosion inhibitor and a surfactant; the mass ratio of the extreme pressure agent, the lubricant, the coolant, the defoaming agent, the corrosion inhibitor and the surfactant is 2-15:1-30:1-30:0.01-2:0.1-2:0.1-40; the extreme pressure agent comprises at least one of a sulfurized alkene and a sulfurized fatty acid ester, and is free of chlorine and phosphorus; the lubricant comprises at least one of castor oil triethanolamine and tall oil; the coolant comprises diethyl ethanol; the defoaming agent comprises at least one of a silicone oil emulsifier and a higher alcohol; the corrosion inhibitor comprises triethylene glycol maleate; and the surfactant comprises octylphenyl alcohol. In this way, when a neodymium iron boron magnet is cut by using a diamond wire cutting process, the dissolution of neodymium oxide in the neodymium iron boron magnet cutting waste by the cutting fluid can be avoided, and the recycling rate of the neodymium iron boron magnet cutting waste can be improved.

Description

Cutting fluids and their applications, cutting fluid circulation systems Technical Field

[0001] This application relates to the field of neodymium iron boron magnet cutting technology, and more particularly to a cutting fluid and its application, and a cutting fluid circulation system. Background Technology

[0002] Neodymium iron boron magnet (Nd2Fe) 14 B) Also known as neodymium magnets, they are tetragonal crystals formed from neodymium, iron, and boron, and are one of the most commonly used magnetic materials. Neodymium iron boron magnets are generally sintered into large blocks before being cut for use. However, due to the high hardness and brittleness of neodymium iron boron materials, their processing is quite difficult.

[0003] Currently, the main cutting methods for NdFeB materials include wire electrical discharge machining (EDM), laser cutting, and diamond wire cutting. Among these, EDM and laser cutting are costly, have long processing cycles, low efficiency, and cause significant wear on the NdFeB material. Diamond wire cutting primarily involves bonding diamond abrasive grains to a cutting wire matrix using a bonding process to create bonded abrasive diamond wire. This type of diamond wire exhibits high efficiency and high-quality cutting performance for brittle and hard materials and is widely used in NdFeB material processing. During high-speed diamond wire cutting, cooling fluid is required to reduce the workpiece temperature and improve the cut quality. Currently, oil-based and water-based cutting fluids are available. While oil-based cutting fluids offer good lubrication, they pose a risk of high-temperature flammability, thus limiting cutting speed. Furthermore, as the diameter of the diamond wire decreases, the wetting and cooling effects of oil-based cutting fluids deteriorate due to their higher surface tension. Therefore, water-based cutting fluids are generally preferred for efficient diamond wire cutting of NdFeB materials.

[0004] In the process of developing the existing technology, the inventors discovered that:

[0005] While water-based cutting fluids can match higher cutting speeds, they contain substances that can dissolve neodymium oxide, resulting in a reduction in the mass of the final recycled waste (cutting powder) compared to oil-based cutting fluids. This leads to the loss of the precious metal neodymium during the recycling process and is not conducive to the recycling of neodymium iron boron magnet cutting waste.

[0006] Therefore, there is a need for a cutting fluid that can avoid dissolving neodymium oxide in the cutting waste of neodymium iron boron magnets and meet the requirements of multi-line high-speed cutting. Summary of the Invention

[0007] This application provides a cutting fluid and its application, as well as a cutting fluid circulation system, to solve the technical problem that the recycling rate of NdFeB magnet cutting waste is reduced due to the dissolution of neodymium oxide in water-based cutting fluid.

[0008] Specifically, a cutting fluid is used to prevent the dissolution of neodymium oxide in the cutting waste of neodymium iron boron magnets during the diamond wire cutting process. The cutting fluid includes: extreme pressure agent, lubricant, coolant, defoamer, corrosion inhibitor, and surfactant.

[0009] The mass ratio of each component in the cutting fluid is: extreme pressure agent: lubricant: coolant: defoamer: corrosion inhibitor: surfactant = 2-15: 1-30: 1-30: 0.01-2: 0.1-2: 0.1-40;

[0010] The extreme pressure agent includes at least one of sulfurized olefins and sulfurized fatty acid esters, and is free of chlorine and phosphorus.

[0011] The lubricant includes at least one of castor oil triethanolamine and tall oil;

[0012] The coolant includes diethylethanol;

[0013] The defoamer includes at least one of silicone oil emulsifier and higher alcohol; wherein the higher alcohol includes a plurality of monohydric alcohol molecules containing at least 3 carbon atoms;

[0014] The corrosion inhibitor includes triethylene maleate;

[0015] The surfactant includes octylbenzyl alcohol.

[0016] Furthermore, the cutting fluid also includes silicon carbide particles;

[0017] The mass ratio of each component in the cutting fluid is: extreme pressure agent: lubricant: coolant: defoamer: corrosion inhibitor: surfactant: silicon carbide particles = 2-15: 1-30: 1-30: 0.01-2: 0.1-2: 0.1-40: 0.1-5;

[0018] The silicon carbide particles have a diameter of 20 nanometers to 500 nanometers.

[0019] Furthermore, the extreme pressure agent also includes dimer fatty acids;

[0020] The mass ratio of dimer fatty acid to sulfurized olefin in the extreme pressure agent is: sulfurized olefin: dimer fatty acid = 3-5: 1;

[0021] The sulfurized olefin has a sulfur content of 30%-40%, and the kinematic viscosity of the sulfurized olefin at 40°C is 60-100 centistokes.

[0022] Furthermore, the mass ratio of the castor oil triethanolamine to the tall oil is: castor oil triethanolamine : tall oil = 3-5 : 1.

[0023] This application also provides an application of the cutting fluid described above in avoiding the dissolution of neodymium oxide in the cutting waste of neodymium iron boron magnets during the diamond wire cutting process.

[0024] This application also provides a cutting fluid circulation system.

[0025] Specifically, a cutting fluid circulation system is provided to enable the circulating use of the cutting fluid below 0°C, so as to improve the cutting quality of NdFeB magnets during the diamond wire cutting process. The cutting fluid circulation system is provided with a liquid outlet, a waste liquid treatment device, and a liquid conveying device in sequence along the flow direction of the cutting fluid.

[0026] The liquid outlet section is provided with an inlet and an outlet;

[0027] The waste liquid treatment device includes: a waste liquid collector, a waste liquid purifier, a purified cutting fluid collector, and a cooling component;

[0028] The waste liquid collector is provided with a waste liquid inlet, a first connection part, and a second connection part;

[0029] The waste liquid purifier is provided with a third connection part, a waste liquid inlet to be purified, and a purified waste liquid outlet part; the third connection part is connected to the first connection part.

[0030] The purified cutting fluid collector is provided with a purified waste fluid inlet, a fourth connection part, and a cooled cutting fluid outlet part; the purified waste fluid inlet is connected to the second connection part;

[0031] The cooling component is provided with a fifth connecting part; the fifth connecting part is connected to the fourth connecting part;

[0032] The liquid conveying device is provided with a liquid inlet and a liquid outlet; the liquid inlet is connected to the cooling cutting fluid outlet; and the liquid outlet is connected to the liquid inlet of the liquid outlet section.

[0033] Furthermore, the cooling component cools down through heat exchange via a liquid ammonia heat pipe.

[0034] Furthermore, the waste liquid purifier includes:

[0035] A waste liquid filter layer is connected to the waste liquid collector; the waste liquid filter layer has an inlet for waste liquid to be purified on a first side and an outlet for purified waste liquid on a second side opposite to the first side.

[0036] A neodymium iron boron magnet cutting waste collection assembly connected to the waste liquid collector.

[0037] Furthermore, the neodymium iron boron magnet cutting waste collection assembly includes:

[0038] A magnetic attractor is used to attract neodymium iron boron magnets in the mixture to cut waste materials by magnetic force.

[0039] Furthermore, the waste liquid filter layer is provided with filter holes;

[0040] The diameter of the filter pores is 20 nanometers to 1000 nanometers.

[0041] The technical solution provided in this application has at least the following beneficial effects:

[0042] By using a chlorine-free extreme pressure agent to formulate a water-based cutting fluid, the dissolution of neodymium oxide in the cutting waste of NdFeB magnets can be avoided during diamond wire cutting, thereby improving the recycling rate of NdFeB magnet cutting waste. Furthermore, the water-based cutting fluid provided in this application can be used below 0°C, effectively enhancing the heat dissipation capacity of the cutting fluid and improving the cutting quality of NdFeB magnets. Attached Figure Description

[0043] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0044] Figure 1 is a scanning electron microscope image of the waste material cut by neodymium iron boron magnets in the presence of conventional cutting fluid.

[0045] Figure 2 is a scanning electron microscope image of the neodymium iron boron magnet cutting waste obtained by using the cutting fluid provided in the embodiment of this application at room temperature.

[0046] Figure 3 is a scanning electron microscope image of the neodymium iron boron magnet cutting waste obtained by using the cutting fluid provided in the embodiment of this application at 0°C.

[0047] Figure 4 is a schematic diagram of a cutting fluid circulation system provided in an embodiment of this application.

[0048] Figure 5 is a schematic diagram of another cutting fluid circulation system provided in an embodiment of this application.

[0049] Figure 6 is a schematic diagram of another cutting fluid circulation system provided in an embodiment of this application.

[0050] The reference numerals in the figure are as follows:

[0051] 100 Cutting Fluid Circulation System

[0052] 1 Liquid outlet

[0053] 2 Waste liquid treatment device

[0054] 21 Waste Liquid Collector

[0055] 22 Waste Liquid Purifier

[0056] 221 Waste Liquid Filtration Layer

[0057] 222 NdFeB magnet cutting waste collection assembly

[0058] 23. Purified cutting fluid collector

[0059] 24 Cooling Components

[0060] 3 Liquid conveying device

[0061] 200 NdFeB magnets

[0062] 300 diamond wire. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0064] Understandably, the process of cutting large NdFeB magnets using diamond wire cutting will generate NdFeB magnet cutting waste. Furthermore, due to the high-speed cutting, friction occurs between the diamond wire and the NdFeB magnet surface, causing a rapid increase in the surface temperature of the NdFeB magnet workpiece. Therefore, cutting fluid is needed to clean the cutting waste from the NdFeB magnet surface and to lubricate and cool the cutting area.

[0065] The microstructure of NdFeB alloys mainly consists of three phases. The main phase is Nd₂Fe, which accounts for more than 90% of the total volume. 14B; the other two phases are neodymium-rich and boron-rich phases, respectively. Furthermore, neodymium in NdFeB magnet cutting waste is oxidized to neodymium oxide in the air. When water-based cutting fluid cleans NdFeB magnets, the components in the cutting fluid react with substances in the NdFeB magnet cutting waste. In particular, when the water-based cutting fluid contains substances that react with neodymium oxide, it dissolves the neodymium oxide. At this point, the final recovered cutting waste is reduced by 3wt.%-5wt.% compared to the cutting waste obtained using oil-based cutting fluid. Therefore, it can be seen that water-based cutting fluid acts as a solvent for neodymium oxide in NdFeB magnet cutting waste, causing neodymium loss. This is not conducive to the recycling of NdFeB magnet cutting waste. Therefore, this application provides a novel water-based cutting fluid to reduce the dissolution of neodymium oxide in NdFeB magnet cutting waste during high-speed diamond wire cutting of NdFeB magnets.

[0066] Specifically, the cutting fluid provided in this application includes: extreme pressure agent, lubricant, coolant, defoamer, corrosion inhibitor, and surfactant;

[0067] The mass ratio of each component in the cutting fluid is: extreme pressure agent: lubricant: coolant: defoamer: corrosion inhibitor: surfactant = 2-15: 1-30: 1-30: 0.01-2: 0.1-2: 0.1-40;

[0068] The extreme pressure agent includes at least one of sulfurized olefins and sulfurized fatty acid esters, and is free of chlorine and phosphorus.

[0069] The lubricant includes at least one of castor oil triethanolamine and tall oil;

[0070] The coolant includes diethylethanol;

[0071] The defoamer includes at least one of silicone oil emulsifier and higher alcohol; wherein the higher alcohol includes a plurality of monohydric alcohol molecules containing at least 3 carbon atoms;

[0072] The corrosion inhibitor includes triethylene maleate;

[0073] The surfactant includes octylbenzyl alcohol.

[0074] It is understandable that extreme pressure agents in cutting fluids can form an extreme pressure lubricating film on the surface of the material being cut during the cutting process, thereby enhancing the extreme pressure properties of the material, preventing sintering on the cut surface, and protecting the diamond wire surface particles from high-temperature abrasion and carbonization. Lubricants in cutting fluids can reduce wear, extend tool life, and improve the cutting quality of the cut surface. Coolants in cutting fluids can lower the cutting temperature of the cutting tool and the surface of the material being cut during the cutting process, thereby reducing thermal deformation and improving machining accuracy. Defoamers in cutting fluids can reduce the surface tension of the fluid, causing stress imbalance in existing bubbles, thus achieving defoaming and foam suppression. Corrosion inhibitors in cutting fluids can reduce the rate at which certain components corrode the material being cut, thereby improving the cutting quality of the cut surface. Surfactants in cutting fluids can reduce the interfacial tension between the components, allowing each component to be uniformly and stably dispersed in the solvent.

[0075] The extreme pressure agent in the cutting fluid of this application includes at least one of sulfurized olefins and sulfurized fatty acid esters, and is free of chlorine and phosphorus. That is, the extreme pressure agent selected in this application is not a phosphorus-based or chlorine-based extreme pressure agent. It is understood that extreme pressure agents are generally classified into sulfur-based, phosphorus-based, and chlorine-based types. Among them, sulfur-based extreme pressure agents have superior load-bearing capacity. Furthermore, sulfur-based extreme pressure agents form a chemical film through direct reaction with the workpiece surface, exhibiting good chemical activity. Phosphorus-based extreme pressure agents have lower load-bearing capacity than sulfur-based extreme pressure agents. Moreover, the reaction between phosphorus-based extreme pressure agents and the workpiece surface is through thermal degradation to form a chemical film, resulting in lower chemical activity than sulfur-based extreme pressure agents. In addition, phosphorus-based extreme pressure agents can cause certain environmental hazards and are not environmentally friendly. Chlorine-based extreme pressure agents can dissolve neodymium oxide in NdFeB magnets to a certain extent. Specifically, chloride ions, as nucleophiles, attack Nd₂O₃ crystals, weakening Nd₂O₃. 3+ With O 2- The electrostatic interaction between them ultimately causes chloride ions to replace O. 2- With Nd 3+ The neodymium oxide in the neodymium iron boron magnet is dissolved by the combination of the complex ions. Therefore, the extreme pressure agent selected in this application is not a phosphorus-based or chloride-based extreme pressure agent, but a sulfur-based extreme pressure agent with high loading capacity and film-forming properties.

[0076] Based on considerations of the viscosity of extreme pressure agents, the extreme pressure agent in this application is at least one of sulfurized olefins and sulfurized fatty acid esters. Specifically, when cutting neodymium iron boron magnets using diamond wire cutting, the diameter of commonly used diamond wires is 100-150 micrometers, and even the finest diamond wires have a diameter of only 35 micrometers. This results in a relatively narrow cutting kerf on the workpiece surface, which in turn places high demands on the fluidity of the extreme pressure agent. Sulfated olefins and sulfurized fatty acid esters have relatively low viscosity and good fluidity; therefore, this application uses at least one of sulfurized olefins and sulfurized fatty acid esters as the extreme pressure agent.

[0077] Furthermore, in a preferred embodiment provided in this application, the extreme pressure agent further includes dimer fatty acids; the mass ratio of dimer fatty acids to sulfurized olefins in the extreme pressure agent is: sulfurized olefins: dimer fatty acids = 3-5:1; the sulfurized olefins have a sulfur content of 30%-40%, and the kinematic viscosity of the sulfurized olefins at 40°C is 60-100 centistokes.

[0078] It is understandable that dimer fatty acids are good additives for water-based metalworking fluids, as they are miscible with water to form transparent, water-soluble lubricants. Furthermore, the oily groups of dimer fatty acids possess excellent friction-reducing and anti-wear properties. Under extreme pressure conditions, dimer fatty acids can react with the friction surfaces to form a dimer fatty acid metal salt soap film, thus achieving extreme pressure anti-wear effects. Therefore, the extreme pressure agent provided in this application also includes dimer fatty acids to enhance its anti-wear performance. Specifically, considering the impact of the extreme pressure agent on the subsequent diamond wire cutting effect, this application sets the mass ratio of dimer fatty acids to sulfurized olefins in the extreme pressure agent to be: sulfurized olefins : dimer fatty acids = 3-5 : 1. Furthermore, the sulfurized olefins have a sulfur content of 30%-40%, and the kinematic viscosity at 40°C is 60-100 centistokes.

[0079] Furthermore, the lubricant in the cutting fluid of this application includes at least one of castor oil triethanolamine and tall oil. In a preferred embodiment provided in this application, considering the lubricating effect of the lubricant in the cutting fluid, the mass ratio of castor oil triethanolamine to tall oil is: castor oil triethanolamine : tall oil = 3-5 : 1. The coolant in the cutting fluid of this application includes diethylethanol. The diethylethanol can be a mixture of polyethylene glycol and ethylene glycol. The defoamer in the cutting fluid of this application includes at least one of silicone oil emulsifier and higher alcohols; wherein the higher alcohols include a plurality of monohydric alcohol molecules containing at least 3 carbon atoms. The higher alcohols can also be understood as a mixture of monohydric alcohols having more than three carbon atoms. The corrosion inhibitor in the cutting fluid of this application includes triethylene maleate. The surfactant in the cutting fluid of this application includes octylbenzyl alcohol. Octylbenzyl alcohol can be called TX-10. Furthermore, the mass ratio of each component in the cutting fluid of this application is: extreme pressure agent: lubricant: coolant: defoamer: corrosion inhibitor: surfactant = 2-15: 1-30: 1-30: 0.01-2: 0.1-2: 0.1-40.

[0080] Furthermore, in a preferred embodiment provided in this application, the cutting fluid further includes silicon carbide particles;

[0081] The mass ratio of each component in the cutting fluid is: extreme pressure agent: lubricant: coolant: defoamer: corrosion inhibitor: surfactant: silicon carbide particles = 2-15: 1-30: 1-30: 0.01-2: 0.1-2: 0.1-40: 0.1-5; wherein the particle diameter of the silicon carbide particles is 20 nanometers-500 nanometers.

[0082] Silicon carbide, also known as diamond abrasive, is added to cutting fluid. When silicon carbide particles are added, they form a stable nanofluid under the action of the surfactant TX-10, thereby increasing the thermal conductivity of the cutting fluid. In other words, adding silicon carbide particles to the cutting fluid improves its thermal conductivity, better dissipating heat from the neodymium iron boron magnet and diamond wire cutting tool. This makes the cutting fluid provided in this application suitable for high-speed diamond wire cutting applications. Specifically, it increases the cutting speed of the diamond wire, thereby improving the cutting efficiency of the neodymium iron boron magnet.

[0083] Specifically, considering the overall dispersion state of silicon carbide particles in the cutting fluid solution, if the particle diameter is too small, they are prone to agglomeration in the cutting fluid solution, thus affecting the thermal conductivity of the final nanofluid. If the particle diameter is too large, they are prone to sedimentation in the cutting fluid solution, resulting in the inability to form a stable suspension, thus affecting the thermal conductivity of the final nanofluid. Therefore, the silicon carbide particles used in this application have a particle diameter of 20 nm to 500 nm. Furthermore, after adding silicon carbide particles to the cutting fluid, the mass ratio of each component in the cutting fluid is: extreme pressure agent: lubricant: coolant: defoamer: corrosion inhibitor: surfactant: silicon carbide particles = 2-15: 1-30: 1-30: 0.01-2: 0.1-2: 0.1-40: 0.1-5.

[0084] This application also provides an application of the above-mentioned cutting fluid in avoiding the dissolution of neodymium oxide in the cutting waste of neodymium iron boron magnets during the diamond wire cutting process.

[0085] The specific embodiments of the cutting fluid provided in this application in the process of cutting neodymium iron boron magnets using diamond wire cutting technology are as follows.

[0086] Example 1

[0087] (1) Prepare the cutting fluid

[0088] Weigh out 100g of castor oil triethanolamine, 33g of tall oil, 30g of sulfurized olefins, 10g of dimer fatty acids, 10g of octylbenzyl alcohol TX-10, 5g of diethylethanol, 1g of triethylene maleate, and 1g of silicone oil emulsion, add them to water to make the total weight of the mixed solution 500g, and stir magnetically for 1 hour in a heating environment at 60℃.

[0089] Weigh 2g of diamond with a particle size of 20nm-500nm, add it to 498g of aqueous solution containing 20g of TX-10 surfactant, and stir magnetically for 1 hour to obtain a suspension containing diamond.

[0090] The two liquids prepared above are mixed and magnetically stirred for 1 hour to obtain the cutting fluid.

[0091] (2) Application of cutting fluid in the process of cutting neodymium iron boron magnets using diamond wire cutting technology

[0092] During the cutting process of neodymium iron boron magnets (diamond wire diameter 150μm, feed rate: 0.6mm / min) using diamond wire cutting technology, the temperature of the cutting fluid is controlled at 0℃, and the cutting fluid is sprayed onto the cutting working area of ​​the neodymium iron boron magnet.

[0093] Collect 25ml of cutting waste liquid;

[0094] The neodymium ion content in cutting waste liquid was determined by ICP (Inductively Coupled Plasma Emission Spectrometer).

[0095] Example 2

[0096] (1) Prepare the cutting fluid

[0097] Weigh out 160g of castor oil triethanolamine, 40g of tall oil, 8g of sulfurized olefins, 2g of dimer fatty acids, 10g of octylbenzyl alcohol TX-10, 20g of diethylethanol, 2g of triethylene glycol maleate, and 1g of silicone oil emulsion. Add them to water to make the total weight of the mixed solution 500g. Stir magnetically for 1 hour in a heating environment at 60℃.

[0098] Weigh 5g of diamond with a particle size of 20nm-500nm, add it to 495g of aqueous solution containing 20g of TX-10 surfactant, and stir magnetically for 1 hour to obtain a suspension containing diamond.

[0099] Mix the two liquids prepared above and continue to stir magnetically for 1 hour.

[0100] (2) Application of cutting fluid in the process of cutting neodymium iron boron magnets using diamond wire cutting technology

[0101] During the cutting process of neodymium iron boron magnets (diamond wire diameter 150μm, feed rate: 0.6mm / min) using diamond wire cutting technology, the temperature of the cutting fluid is controlled at 0℃, and the cutting fluid is sprayed onto the cutting working area of ​​the neodymium iron boron magnet.

[0102] Collect 25ml of cutting waste liquid;

[0103] The neodymium ion content in cutting waste liquid was determined by ICP method.

[0104] Example 3

[0105] (1) Prepare the cutting fluid

[0106] Weigh out 50g of castor oil triethanolamine, 10g of tall oil, 50g of sulfurized olefins, 10g of dimer fatty acids, 10g of octylbenzenesilol TX-10, 50g of diethylethanol, 10g of triethylene maleate, and 5g of silicone oil emulsion. Add them to water to make the total weight of the mixed solution 500g. Stir magnetically for 1 hour in a heating environment at 60℃.

[0107] Weigh 20g of diamond with a particle size of 20nm-500nm, add it to 480g of aqueous solution containing 30g of TX-10 surfactant, and stir magnetically for 1 hour to obtain a suspension containing diamond.

[0108] Mix the two liquids prepared above and continue to stir magnetically for 1 hour.

[0109] (2) Application of cutting fluid in the process of cutting neodymium iron boron magnets using diamond wire cutting technology

[0110] During the cutting process of neodymium iron boron magnets (diamond wire diameter 150μm, feed rate: 0.6mm / min) using diamond wire cutting technology, the temperature of the cutting fluid is controlled at 0℃, and the cutting fluid is sprayed onto the cutting working area of ​​the neodymium iron boron magnet.

[0111] Collect 25ml of cutting waste liquid;

[0112] The neodymium ion content in cutting waste liquid was determined by ICP method.

[0113] It should be noted that neodymium is an element that is highly susceptible to oxidation. Directly determining the neodymium oxide content in NdFeB magnet cutting waste inevitably results in oxidation of the neodymium in the waste during sampling and testing, causing fluctuations in the test data. Therefore, this application uses the ICP method to directly determine the neodymium ion content in the cutting waste liquid to demonstrate that the cutting fluid provided in this application can avoid dissolving neodymium oxide in the NdFeB magnet cutting waste.

[0114] Measurements showed that the neodymium ion content in the cutting waste fluid corresponding to Example 1 was 2 mg / L; the neodymium ion content in the cutting waste fluid corresponding to Example 2 was 2.3 mg / L; and the neodymium ion content in the cutting waste fluid corresponding to Example 3 was 2.4 mg / L. Meanwhile, the neodymium ion content in the cutting waste fluid obtained by using a control group of water-based cutting fluid for diamond wire cutting of neodymium iron boron magnets (diamond wire diameter 150 μm, feed rate: 0.6 mm / min) was 43 mg / L. Compared to existing water-based cutting fluids, the neodymium ion content in the cutting waste fluid corresponding to the water-based cutting fluid provided in this application is reduced by more than 90% (95.34% in Example 1, 94.65% in Example 2, and 94.42% in Example 3). Therefore, the cutting fluid provided in this application can significantly reduce the dissolution of neodymium oxide in the cutting waste of neodymium iron boron magnets.

[0115] Furthermore, by comparing the weight of the recycled NdFeB magnet cutting waste corresponding to each square meter of NdFeB magnet cut, it can be proven that the cutting fluid provided in this application can avoid dissolving neodymium oxide in the NdFeB magnet cutting waste. That is, after cutting large NdFeB magnets using the same diamond wire cutting parameters (diamond wire diameter 150μm, feed rate: 0.6mm / min), the NdFeB magnet cutting waste generated from cutting each square meter of NdFeB magnet is recycled and weighed.

[0116] The waste materials from the cutting of NdFeB magnets were recovered and weighed: Example 1 yielded 1100g of waste material; Example 2 yielded 1095g; and Example 3 yielded 1089g. Meanwhile, the control group, using water-based cutting fluid, yielded 1054g of waste material. Compared to existing water-based cutting fluids, the water-based cutting fluid provided in this application yields significantly higher weights of waste material from NdFeB magnet cutting. Therefore, the cutting fluid provided in this application can significantly reduce the dissolution of NdFeB magnet cutting waste.

[0117] In summary, both ICP determination of neodymium ion content in neodymium iron boron magnet cutting waste liquid and recycling and weighing of neodymium iron boron magnet cutting waste demonstrate that the cutting fluid provided in this application can significantly reduce the dissolution of neodymium oxide in neodymium iron boron magnet cutting waste.

[0118] It should also be noted that neodymium iron boron magnets are brittle materials. During the diamond wire cutting process of neodymium iron boron magnets, the lower the cutting temperature, the shorter the transverse and longitudinal cracks on the surface of the magnet caused by the cutting. That is, as the cutting temperature decreases, the size of the debris in the neodymium iron boron magnet cutting waste will decrease, thereby improving the yield of the cut products and reducing the scrap rate. Therefore, to improve the heat dissipation capacity of the water-based cutting fluid, the cutting fluid provided in this application is for use at temperatures below 0°C rather than at room temperature. This further enhances the thermal conductivity of the cutting fluid, thereby contributing to improved cutting quality.

[0119] Specifically, please refer to Figure 1, which shows the electron microscope (EM) scan of the cutting waste obtained from NdFeB magnet cutting using conventional water-based cutting fluid. According to the EEM scan in Figure 1 (EM scanning parameters: accelerating voltage 15KV, working distance 12.5mm, magnification 1.5K, scanning mode BSE backscattered electron scanning mode, scale bar 30.0μm), the morphology of the NdFeB magnet cutting waste obtained using conventional cutting fluid is agglomerated and elongated. The size of the agglomerated debris is mostly distributed in the range of 5-8 micrometers, while the length of the elongated debris ranges from 10-20 micrometers.

[0120] Please refer to Figure 2, which shows an electron microscope (EM) image of the NdFeB magnet cutting waste obtained when the cutting fluid corresponding to Example 1 was used at room temperature. According to the EEM image in Figure 2 (EM scanning parameters: accelerating voltage 15KV, working distance 12.7mm, magnification 1.5K, scanning mode BSE backscattered electron scanning mode, scale bar 30.0μm), the morphology of the NdFeB magnet cutting waste obtained using the cutting fluid provided in this application at room temperature is agglomerated and elongated. However, the size of the agglomerated debris is mostly distributed in the range of 3-6 micrometers, and the length of the elongated debris ranges from 7-15 micrometers.

[0121] Please refer to Figure 3, which shows the electron microscope (EM) image of the NdFeB magnet cutting waste obtained when the cutting fluid corresponding to Example 1 was used below 0°C. According to the EEM image in Figure 3 (EM scanning parameters: accelerating voltage 15KV, working distance 12.8mm, magnification 1.5K, scanning mode BSE backscattered electron scanning mode, scale bar 30.0μm), the morphology of the NdFeB magnet cutting waste obtained using the cutting fluid provided in this application below 0°C is agglomerated and elongated. However, the size of the agglomerated debris is mostly distributed in the range of 2-4 micrometers, and the length of the elongated debris is within 5 micrometers.

[0122] Therefore, it can be seen that the cutting fluid provided in this application can reduce the size of the cutting powder when used below 0°C, thereby improving the yield of the base material and the surface cutting quality.

[0123] To enable the cutting fluid to be circulated below 0°C, please refer to Figure 3. This application also provides a cutting fluid circulation system 100.

[0124] The cutting fluid circulation system 100 is used in the cutting process of cutting neodymium iron boron magnets 200 with diamond wire 300, and the cutting fluid circulation system 100 can realize the circulation of the cutting fluid below 0°C.

[0125] Specifically, please refer to Figures 3 to 5. The cutting fluid circulation system 100 provided in this application is provided with a liquid outlet 1, a waste liquid treatment device 2, and a liquid conveying device 3 in sequence along the flow direction of the cutting fluid.

[0126] The liquid outlet section 1 is provided with an inlet and an outlet;

[0127] Waste liquid treatment device 2 includes: waste liquid collector 21, waste liquid purifier 22, purified cutting fluid collector 23, and cooling component 24;

[0128] Waste liquid collector 21 is provided with waste liquid inlet, first connection part and second connection part;

[0129] Waste liquid purifier 22 is provided with a third connection part, a waste liquid inlet to be purified, and a purified waste liquid outlet part; the third connection part is connected to the first connection part;

[0130] The purified cutting fluid collector 23 is provided with a purified waste fluid inlet, a fourth connection part, and a cooled cutting fluid outlet part; the purified waste fluid inlet is connected to the second connection part;

[0131] The cooling component 24 is provided with a fifth connecting part; the fifth connecting part is connected to the fourth connecting part;

[0132] The liquid conveying device 3 is provided with a liquid inlet and a liquid outlet; the liquid inlet is connected to the cooling cutting fluid outlet; and the liquid outlet is connected to the liquid inlet of the liquid outlet section 1.

[0133] After the cutting fluid flows out from the outlet 1, it acts on the cutting area of ​​the NdFeB magnet. Subsequently, the NdFeB magnet cutting waste generated during the cutting process is collected together with the cutting fluid and sent to the waste liquid treatment device 2 under the flushing action of the cutting fluid. This application considers the mixture formed by the NdFeB magnet cutting waste and the cutting fluid as waste liquid. The waste liquid treatment device 2 provided in this application purifies the waste liquid and cools the purified cutting fluid. Finally, the cooled and purified cutting fluid is transported to the outlet 1 through the liquid conveying device 3 and flows out from the outlet of the outlet 1.

[0134] Specifically, the waste liquid treatment device 2, which purifies the waste liquid and cools the purified cutting fluid, includes: a waste liquid collector 21, a waste liquid purifier 22, a purified cutting fluid collector 23, and a cooling component 24. The waste liquid collector 21 has a waste liquid inlet. Waste liquid enters the waste liquid collector 21 through the waste liquid inlet. In one specific embodiment provided in this application, the waste liquid inlet and the outlet of the outlet section 1 are respectively located directly above and below the diamond wire cutting area of ​​the neodymium iron boron magnet. This facilitates the full utilization and recycling of the cutting fluid. The waste liquid inlet can be designed as a regular shape such as a circle or square, depending on the actual situation. Furthermore, the waste liquid collector 21 also has a first connecting part for connecting to the waste liquid purifier 22 and a second connecting part for connecting to the purified cutting fluid collector 23. The first connecting part can be flexibly designed according to the shape and distribution of the waste liquid inlet to be purified and the purified waste liquid outlet in the waste liquid purifier 22. The second connecting part can also be understood as the purified waste liquid outlet of the waste liquid collector 21. The second connection can be located on the side of the waste liquid collector 21 near the bottom, or at the bottom of the waste liquid collector 21. The purified waste liquid will flow out of the waste liquid collector 21 through the second connection.

[0135] Correspondingly, the waste liquid purifier 22 is provided with a third connecting part for connecting to the waste liquid collector 21, and the third connecting part is connected to the first connecting part, thereby realizing the connection between the waste liquid purifier 22 and the waste liquid collector 21. Furthermore, the waste liquid purifier 22 is provided with an inlet for waste liquid to be purified and an outlet for purified waste liquid. After being purified by the waste liquid purifier 22, the cutting fluid and NdFeB magnet cutting waste in the waste liquid can be separated. The purified waste liquid outlet can also be understood as the outlet for the cutting fluid obtained after removing the NdFeB magnet cutting waste from the waste liquid.

[0136] Similarly, to connect the purified cutting fluid collector 23 to the waste fluid collector 21, the purified cutting fluid collector 23 is provided with a waste fluid collector 21 connection portion for connecting to the waste fluid collector 21. This waste fluid collector 21 connection portion can also be understood as a purified waste fluid inlet. By connecting the purified waste fluid inlet to the second connection portion, the cutting fluid purified by the waste fluid purifier 22 can enter the purified cutting fluid collector 23. Furthermore, to achieve cooling treatment of the purified cutting fluid, the purified cutting fluid collector 23 is also provided with a fourth connection portion for connecting to the cooling assembly 24.

[0137] Correspondingly, the cooling assembly 24 is provided with a fifth connecting part that connects to the fourth connecting part. By connecting the fifth connecting part to the fourth connecting part, the cooling assembly 24 can be connected to the purified cutting fluid collector 23. Under the action of the cooling assembly 24, the purified cutting fluid in the purified cutting fluid collector 23 will be cooled to below 0°C.

[0138] In addition, the purified cutting fluid collector 23 is also provided with a cooled cutting fluid outlet for the cooled purified cutting fluid to flow out. The cooled purified cutting fluid will flow out through the cooled cutting fluid outlet to the liquid conveying device 3, and then be conveyed by the liquid conveying device 3 to the liquid outlet 1.

[0139] Correspondingly, the liquid delivery device 3 is provided with a liquid inlet for the cooled and purified cutting fluid to flow in, and a liquid outlet for the cooled and purified cutting fluid to flow out. Connecting the liquid inlet to the cooled cutting fluid outlet connects the liquid delivery device 3 to the purified cutting fluid collector 23. Furthermore, connecting the liquid outlet to the inlet of the outlet section 1 connects the liquid delivery device 3 to the outlet section 1. The cooled and purified cutting fluid will eventually flow out from the liquid outlet, then through the inlet into the outlet section 1, and finally out through the outlet to act on the diamond wire cutting area of ​​the neodymium iron boron magnet.

[0140] Furthermore, in a preferred embodiment provided in this application, the cooling component 24 cools down by heat exchange through a liquid ammonia heat pipe.

[0141] Understandably, depending on the cooling principle of heat pipes and the different working media, liquid ammonia, liquid nitrogen, Freon, or distilled water can generally be used for heat exchange and cooling. However, considering the properties of the cutting fluid being cooled and the requirements for cooling rate and temperature control, this application prefers to use liquid ammonia for cooling. Specifically, a liquid ammonia heat pipe can be used to cool the purified cutting fluid.

[0142] Furthermore, in a preferred embodiment provided in this application, the waste liquid purifier 22 includes:

[0143] A waste liquid filter layer 221 is connected to the waste liquid collector 21; the waste liquid filter layer 221 is provided with a waste liquid inlet to be purified on a first side and a purified waste liquid outlet on a second side opposite to the first side.

[0144] Neodymium iron boron magnet cutting waste collection assembly 222 connected to waste liquid collector 21.

[0145] The waste liquid filter layer 221 here can be understood as a filter plate with several through holes. The opening on the side of the through hole closest to the waste liquid to be purified can be understood as the inlet of the waste liquid to be purified. Correspondingly, the opening on the side of the through hole furthest from the waste liquid to be purified can be understood as the outlet of the purified waste liquid. By controlling the size of the through holes, the waste liquid can be filtered and separated, thereby obtaining purified cutting fluid.

[0146] In addition, this application also includes a NdFeB magnet cutting waste collection assembly 222 for collecting NdFeB magnet cutting waste from waste liquid. The NdFeB magnet cutting waste collection assembly 222 can be located at the bottom of the waste liquid collector 21, close to the inlet of the waste liquid to be purified. In this way, the NdFeB magnet cutting waste filtered by the waste liquid filter layer 221 can settle into the NdFeB magnet cutting waste collection assembly 222, and then be recycled.

[0147] Furthermore, in a preferred embodiment provided in this application, the NdFeB magnet cutting waste collection assembly 222 includes: a magnetic adsorption element for magnetically adsorbing NdFeB magnet cutting waste in the waste liquid collected by the waste liquid collector 21.

[0148] It is understandable that neodymium iron boron magnets possess a certain degree of magnetism. Therefore, neodymium iron boron magnet cutting waste also possesses a certain degree of magnetism. In order to accelerate the settling speed of neodymium iron boron magnet cutting waste in the waste liquid, the neodymium iron boron magnet cutting waste collection assembly 222 of this application is also provided with a magnetic attraction element to accelerate the settling of neodymium iron boron magnet cutting waste in the waste liquid through magnetic force.

[0149] In one specific embodiment provided in this application, the magnetic attractor can be an electromagnet. In this case, the electromagnet can be placed outside the waste liquid collector 21, near the bottom of the waste liquid collector 21. When the electromagnet is energized, the NdFeB magnet cutting waste in the waste liquid will be attracted to the bottom of the waste liquid collector 21. To facilitate the removal of the settled NdFeB magnet cutting waste, a waste collection carrier for collecting the NdFeB magnet cutting waste can also be provided in the magnetic attractor. Furthermore, the bottom of the carrier can be provided with a through hole with a diameter smaller than the diameter of the NdFeB magnet cutting waste particles, so that liquid can drain out from the carrier.

[0150] Furthermore, in a preferred embodiment provided in this application, the waste liquid filter layer 221 is provided with filter holes; the diameter of the filter holes is 20 nanometers to 1000 nanometers.

[0151] Considering that the size of NdFeB magnet cutting waste generated when cutting NdFeB magnets using diamond wire cutting technology is generally in the range of 2-10 micrometers, and the size of individual NdFeB magnet cutting waste can reach 1 micrometer, in order to prevent NdFeB magnet cutting waste from passing through the through-holes of the waste liquid filter layer 221, this application sets the maximum pore size of the filter pores of the waste liquid filter layer 221 to 1 micrometer. Furthermore, considering that the silicon carbide particle diameter in the silicon carbide nanofluid in the cutting fluid provided in this application is 20 nanometers-500 nanometers, in order to allow silicon carbide particles to pass through the filter pores, this application sets the minimum pore size of the filter pores of the waste liquid filter layer 221 to 20 nanometers. That is, the diameter of the filter pores in the filter layer provided in this application is 20 nanometers-1000 nanometers.

[0152] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0153] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A cutting fluid used to prevent the dissolution of neodymium oxide in neodymium iron boron magnet cutting waste during the diamond wire cutting process, characterized in that, The cutting fluid comprises: extreme pressure agent, lubricant, coolant, defoamer, corrosion inhibitor, surfactant, and silicon carbide particles; the mass ratio of each component in the cutting fluid is: extreme pressure agent: lubricant: coolant: defoamer: corrosion inhibitor: surfactant: silicon carbide particles = 2-15: 1-30: 1-30: 0.01-2: 0.1-2: 0.1-40: 0.1-5; wherein the silicon carbide particles have a particle diameter of 20 nm to 500 nm; the extreme pressure agent comprises at least one of sulfurized olefins and sulfurized fatty acid esters, and is chlorine-free and phosphorus-free; the lubricant comprises at least one of castor oil triethanolamine and tall oil; the coolant is a mixture of polyethylene glycol and ethylene glycol; the defoamer comprises at least one of silicone oil emulsifier and higher alcohols; wherein the higher alcohol is a mixture of monohydric alcohols having three or more carbon atoms; the corrosion inhibitor comprises triethylene maleate; and the surfactant comprises octylbenzeneol.

2. The cutting fluid as described in claim 1, characterized in that, The extreme pressure agent also includes dimer fatty acids; the mass ratio of dimer fatty acids to sulfurized olefins in the extreme pressure agent is: sulfurized olefins: dimer fatty acids = 3-5:1; the sulfurized olefins have a sulfur content of 30%-40%, and the kinematic viscosity of the sulfurized olefins at 40°C is 60-100 centistokes.

3. The cutting fluid as described in claim 1, characterized in that, The mass ratio of castor oil triethanolamine to tall oil is: castor oil triethanolamine : tall oil = 3-5 :

1.

4. The application of the cutting fluid as described in claim 1 in the process of cutting NdFeB magnets using diamond wire cutting technology to avoid dissolving NdFeB magnet cutting waste.

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