Environment-friendly pure tin ultra-precision machining cutting fluid and preparation method thereof

Abstract

The invention relates to the technical field of cutting fluid preparation, and particularly discloses an environment-friendly pure-tin ultra-precision machining cutting fluid and a preparation method thereof.The environment-friendly pure-tin ultra-precision machining cutting fluid is prepared from, by mass, 8-13% of binary composite coolant, 10-15% of ester lubricant, 3-5% of composite antirust agent, 3-5% of lubricant and the balance water. 0.5-1% of a pH stabilizer and the balance of deionized water; the binary composite coolant is prepared from 5 to 8 percent of perfluoropolyether oil and 3 to 5 percent of surface modified nanoparticle dispersion liquid; the ester lubricant is pentaerythritol oleate with the viscosity of 8-12 mm < 2 > / s at 40 DEG C. The prepared cutting fluid can form a stable phase change cooling layer, a microsphere lubricating layer and a passivation protective film, the temperature of a cutting area can be effectively reduced, thermal deformation is reduced, and oxidation and corrosion are prevented. Experiments prove that when the cutting fluid is used in 800 rpm tapping of an M6 hard alloy tap (TiAlN coating), the temperature rise can be controlled to be less than or equal to 8 DEG C, the average torque is less than or equal to 125 Ncm, and the surface roughness Ra is less than or equal to 0.05 mu m.

Description

Technical Field

[0001] The invention relates to the technical field of cutting fluid preparation, and in particular to an environmentally friendly pure tin ultra-precision machining cutting fluid and a preparation method thereof. Background Art

[0002] In the field of ultra-precision machining, especially for materials such as pure tin, the choice of cutting fluid has a crucial impact on machining quality, efficiency and tool life. Due to its low melting point (232°C) and low Vickers hardness, pure tin materials are prone to thermal softening, adhesion and scratching during ultra-precision cutting, resulting in increased surface roughness and rapid tool failure. At the same time, pure tin has a high thermal conductivity. On the one hand, it helps the cutting heat dissipate to the substrate, but on the other hand, it makes the concentrated release of heat in the cutting area difficult to control. If the cooling efficiency of the cutting fluid is insufficient, it will cause local overheating or thermal deformation. Therefore, the development of a cutting fluid suitable for ultra-precision machining of pure tin is of great significance for improving machining efficiency and workpiece quality.

[0003] The cutting fluids commonly used on the market currently mainly include emulsified or semi-synthetic, fully synthetic cutting fluids and cutting oils with extreme pressure additives. However, existing cutting fluids have deficiencies in cooling efficiency, lubrication performance and corrosion inhibition performance, especially when it comes to materials such as pure tin that are very sensitive to temperature changes. These deficiencies are particularly evident. For example, although emulsified or semi-synthetic cutting fluids have large heat capacity and fast heat dissipation, they have poor emulsification stability and are easily contaminated by microorganisms. Long-term use can easily breed bacteria and mold, causing the cutting fluid to deteriorate. Fully synthetic cutting fluids have strong stability and corrosion resistance, but insufficient lubrication ability, and are prone to adhesion and wear on low-hardness tin materials, affecting processing accuracy. Cutting oils containing extreme pressure additives have excellent lubricity, but insufficient heat capacity and thermal conductivity, and poor heat dissipation effect during high-speed cutting, which may cause workpiece deformation and fluctuations in processing accuracy. At the same time, additive residues affect subsequent processes. In summary, ultra-precision processing of pure tin urgently needs a cutting fluid formula that takes into account efficient cooling, controllable lubrication and corrosion inhibition protection to meet the multiple needs of precision processing.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide an environmentally friendly pure tin ultra-precision machining cutting fluid and a preparation method thereof, aiming to solve the problems of insufficient cooling, unbalanced lubrication and limited corrosion inhibition performance of existing cutting fluids.

[0006] The technical solutions of the present invention are as follows:

[0007] An environmentally friendly pure tin ultra-precision machining cutting fluid, which comprises, by mass percentage, 8-13% of a binary composite coolant, 10-15% of an ester lubricant, 3-5% of a composite rust inhibitor, 0.5-1% of a pH stabilizer, and the balance deionized water; the binary composite coolant is composed of 5-8% of a perfluoropolyether oil and 3-5% of a surface-modified nanoparticle dispersion; the ester lubricant has a viscosity of 8-12 mm at 40°C. 2 / s of pentaerythritol oleate.

[0008] The environmentally friendly pure tin ultra-precision machining cutting fluid, wherein the perfluoropolyether oil is selected to have a linear structure with a molecular weight of 2000-3000 g / mol, a viscosity of 8-12 cSt at 40° C., and a surface tension of less than 20 mN / m.

[0009] The environmentally friendly pure tin ultra-precision machining cutting fluid, wherein the surface-modified nanoparticle dispersion is a nanoparticle dispersion surface-modified by a silane coupling agent, wherein the nanoparticles are one or more of α-phase Al2O3 particles, MoS2 particles, CuO particles and ZnO particles.

[0010] The environmentally friendly pure tin ultra-precision machining cutting fluid, wherein the particle size of the nanoparticles is 50-100 nm.

[0011] The environmentally friendly pure tin ultra-precision machining cutting fluid, wherein the composite rust inhibitor is composed of 2-3% of benzotriazole derivatives and 1-2% of triethanolamine borate.

[0012] The environmentally friendly pure tin ultra-precision machining cutting fluid, wherein the pH stabilizer is ammonium borate.

[0013] The environmentally friendly pure tin ultra-precision machining cutting fluid further comprises a corrosion inhibitor, which is one of nitrosobenzotriazole, phosphate and imidazole corrosion inhibitors.

[0014] A method for preparing an environmentally friendly pure tin ultra-precision machining cutting fluid, comprising the steps of:

[0015] Weighing by mass percentage 5-8% of perfluoropolyether oil, 3-5% of surface-modified nanoparticle dispersion, 10-15% of ester lubricant, 2-3% of benzotriazole derivative, 1-2% of triethanolamine borate, 0.5-1% of pH stabilizer, and the balance deionized water;

[0016] Adding the perfluoropolyether oil and the surface-modified nanoparticle dispersion into an ultrasonic reactor for ultrasonic treatment to prepare a binary composite coolant;

[0017] Heat the ester lubricant to 50-80°C, start the stirring device, slowly add the benzotriazole derivative, and continue the reaction for 10-30 minutes until the system becomes transparent to prepare the ester lubricant premix;

[0018] Deionized water, binary composite coolant, and ester-based lubricant premix are sequentially added to the reactor, the temperature is controlled at 50-55°C, and triethanolamine borate and boric acid amine salt are added after stirring for 30-50 minutes. Finally, stirring and shearing emulsification are performed for 10-20 minutes to obtain a mixed solution.

[0019] The mixed liquid is passed through a 5 μm precision filter to remove impurities, thereby preparing the environmentally friendly pure tin ultra-precision machining cutting fluid.

[0020] In the method for preparing the environmentally friendly pure tin ultra-precision machining cutting fluid, ultrasonic treatment refers to ultrasonic dispersion at 40-45° C. for 20-40 minutes.

[0021] The method for preparing the environmentally friendly pure tin ultraprecision machining cutting fluid comprises the following steps: after adding triethanolamine borate and boric acid amine salt, adjusting the pH of the system to 8.5-9.2.

[0022] Beneficial effects: The environmentally friendly pure tin ultra-precision machining cutting fluid provided by the present invention is composed of a specific proportion of a binary composite coolant, an ester lubricant, a composite rust inhibitor, a pH stabilizer and deionized water as the remainder, and is prepared by ultrasonic dispersion, high-speed shearing and precision filtration processes. The prepared cutting fluid can form a stable phase change cooling layer, a micro-ball lubrication layer and a passivation protective film, which can effectively reduce the temperature of the cutting area, reduce thermal deformation, and prevent oxidation and corrosion. Experiments have shown that the cutting fluid can control the temperature rise to ≤8°C, the average torque to ≤125Ncm, and the surface roughness to Ra≤0.05μm during 800rpm tapping of an M6 carbide tap (TiAlN coating); the cutting fluid takes into account efficient cooling, dynamic lubrication, long-lasting corrosion inhibition and environmental safety, significantly improving the quality, efficiency and economy of pure tin ultra-precision machining, and is particularly suitable for high-end electronics and precision connectors and other fields, providing an innovative technical solution for the field of pure tin alloy processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of a method for preparing an environmentally friendly pure tin ultra-precision machining cutting fluid. DETAILED DESCRIPTION

[0024] The present invention provides an environmentally friendly pure tin ultraprecision machining cutting fluid and a preparation method thereof. To make the objectives, technical solutions, and effects of the present invention more clear and explicit, the present invention is further described below in detail. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0025] Cutting fluids have the following disadvantages in ultra-precision machining of pure tin: ① Insufficient cooling performance: Pure tin is very sensitive to temperature changes, and the cutting fluid must have excellent cooling capabilities to quickly absorb and conduct the heat generated in the machining area. However, existing cutting fluids may be insufficient in cooling efficiency and cannot meet the demand for rapid heat dissipation during pure tin machining. This lack of cooling performance may lead to inaccurate temperature control during machining, which in turn affects machining accuracy and tool life. ② Insufficient lubricity: The low hardness of pure tin requires the cutting fluid to have excellent lubricity to reduce tool wear and improve the quality of the machined surface. The lubricity of existing cutting fluids is insufficient, especially in high-speed machining. ③ Limited corrosion inhibition performance: The surface of pure tin is easily oxidized after machining, and the anti-rust performance of existing cutting fluids may not be sufficient to protect the pure tin surface, resulting in rapid oxidation of the workpiece after machining.

[0026] Based on this, the present invention provides an environmentally friendly pure tin ultra-precision machining cutting fluid, which comprises, by mass percentage: 8-13% of a binary composite coolant, 10-15% of an ester lubricant, 3-5% of a composite rust inhibitor, 0.5-1% of a pH stabilizer, and the balance deionized water; the binary composite coolant is composed of 5-8% of a perfluoropolyether oil and 3-5% of a surface-modified nanoparticle dispersion; the ester lubricant has a viscosity of 8-12 mm at 40°C. 2 / s of pentaerythritol oleate.

[0027] Specifically, the present invention uses 5-8% perfluoropolyether oil (PEPE) and 3-5% surface-modified nanoparticle dispersion to form a binary composite coolant, which breaks through the single cooling mechanism of traditional cutting fluids and effectively solves the problem of processing heat softening caused by the low melting point of pure tin. The perfluoropolyether oil of the present invention has a molecular weight of 2000-3000g / mol and a viscosity of 8-12mm at 40°C. 2 / s, a linear structure with a surface tension of less than 20mN / m, and its low surface tension and high boiling point characteristics can achieve rapid penetration into the cutting micro-area, and reduce the local temperature by absorbing heat through volatile phase change; the surface-modified nanoparticle dispersion described in the present invention is a nanoparticle dispersion surface-modified by a silane coupling agent, wherein the nanoparticles are one or more of α-phase Al2O3 particles, MoS2 particles, CuO particles and ZnO particles with a particle size of 50-100nm, and the nanoparticles are surface-modified by the silane coupling agent KH-550 to significantly improve the dispersion stability of the particles in the system; the synergistic effect of the two is manifested as: perfluoropolyether oil forms a non-polar low-friction isolation layer on the tool surface to inhibit material adhesion, while the nanoparticles reduce the friction coefficient, reduce frictional heat generation and improve thermal conductivity through the interface micro-ball effect, forming a dual regulation mechanism of physical cooling and dynamic lubrication.

[0028] The ester-based lubricant selected in the present invention has a viscosity of 8-12 mm at 40°C.2 / s pentaerythritol oleate, with a highly branched tetraol ester molecular structure, forms a dynamic viscosity gradient with PEPE through its low viscosity, enabling adaptive lubrication-cooling switching during high-speed machining. The lubricating film and cooling isolation layer simultaneously inhibit oxidation and thermal softening of the machined surface. Specifically, as a core lubricant, pentaerythritol oleate effectively resolves the conflict between excessive lubrication and insufficient cooling in cutting fluids. During low-speed machining, pentaerythritol oleate preferentially adsorbs on the tool surface to form a lubricating film. During high-speed machining, perfluoropolyether oil dominates cooling, while nanoparticles assist in lubrication.

[0029] In some embodiments, the composite rust inhibitor is composed of 2-3% of a benzotriazole derivative and 1-2% of triethanolamine borate. The combination of the two can form a dense passivation film on the surface of pure tin, blocking oxygen and moisture corrosion, thereby effectively inhibiting the oxidation discoloration and electrochemical corrosion of pure tin in a hot and humid environment.

[0030] In some embodiments, the pH stabilizer is an ammonium borate salt. The ammonium borate salt can maintain the pH value of the cutting fluid in a stable range of 8.5-9.2 through the complexation of the weakly basic amine group with boric acid, inhibiting the oxidation and hydrogen embrittlement tendency of pure tin under acidic conditions, preventing chemical corrosion, and ensuring the chemical stability of the cutting fluid under high temperature and high shear conditions.

[0031] In some embodiments, the environmentally friendly pure tin ultraprecision machining cutting fluid further includes a corrosion inhibitor, wherein the corrosion inhibitor is one of nitrosobenzotriazole, phosphate ester, and imidazole corrosion inhibitors. The addition of the corrosion inhibitor further improves the corrosion protection performance of the cutting fluid.

[0032] In some embodiments, the environmentally friendly pure tin ultraprecision machining cutting fluid can also improve the low-temperature fluidity of the cutting fluid by adding organic substances such as triol esters and polyether esters; or enhance the heavy-load anti-wear performance of the cutting fluid by adding sulfur-containing and phosphorus-containing extreme pressure additives.

[0033] In some embodiments, a method for preparing an environmentally friendly pure tin ultra-precision machining cutting fluid is also provided, such as Figure 1 As shown, it includes the steps of:

[0034] S10, weighing by mass percentage 5-8% of perfluoropolyether oil, 3-5% of surface-modified nanoparticle dispersion, 10-15% of ester lubricant, 2-3% of benzotriazole derivative, 1-2% of triethanolamine borate, 0.5-1% of pH stabilizer, and the balance deionized water;

[0035] S20, adding the perfluoropolyether oil and the surface-modified nanoparticle dispersion into an ultrasonic reactor for ultrasonic treatment to prepare a binary composite coolant;

[0036] S30, heating the ester lubricant to 50-80° C., turning on the stirring device, slowly adding the benzotriazole derivative, and continuing the reaction for 10-30 minutes until the system becomes transparent, thereby preparing an ester-based lubricant premix;

[0037] S40, deionized water, binary composite coolant and ester-based lubricant premix are sequentially added to the reactor, the temperature is controlled at 50-55° C., triethanolamine borate and boric acid amine salt are added after stirring for 30-50 minutes, the pH of the system is adjusted to 8.5-9.2, and finally stirring and shearing emulsification is performed for 10-20 minutes to obtain a mixed solution;

[0038] S50, removing impurities from the mixed liquid through a 5 μm precision filter to obtain the environmentally friendly pure tin ultra-precision machining cutting fluid.

[0039] Specifically, this embodiment produces a cutting fluid having a stable phase change cooling layer, a micro-ball lubrication layer and a passivation protective film through ultrasonic treatment, high-speed shearing and precision filtration processes. The cutting fluid can effectively reduce the temperature of the cutting area, reduce thermal deformation, and prevent oxidation and corrosion; wherein the ultrasonic treatment refers to ultrasonic dispersion at 40-45°C for 20-40 minutes.

[0040] The present invention will be further explained below by means of specific embodiments:

[0041] In order to verify that the cutting fluid of the present invention has a significant effect on improving the precision machining quality of pure tin materials, low tapping torque and temperature rise control at high speed are achieved by adjusting the ratio of the binary composite coolant (taking PEPE + nano-Al2O3 particles surface-modified with a silane coupling agent as an example) and the ester-based lubricant (pentaerythritol oleate).

[0042] Example 1

[0043] An environmentally friendly pure tin ultra-precision machining cutting fluid, which comprises, by mass percentage, 8% of a binary composite coolant, 12% of an ester lubricant, 3% of a composite rust inhibitor, 1% of a pH stabilizer, and the balance deionized water; the binary composite coolant is composed of 5% of perfluoropolyether oil and 3% of a nano-Al2O3 particle dispersion modified with a silane coupling agent KH-550; the ester lubricant has a viscosity of 8-12 mm at 40°C. 2 / s of pentaerythritol oleate; the composite rust inhibitor consists of 2% of benzotriazole derivatives and 1% of triethanolamine borate; the pH stabilizer is ammonium borate.

[0044] Example 2

[0045] An environmentally friendly pure tin ultra-precision machining cutting fluid, which comprises, by mass percentage, 10% of a binary composite coolant, 12% of an ester lubricant, 3% of a composite rust inhibitor, 1% of a pH stabilizer, and the balance deionized water; the binary composite coolant is composed of 6% of perfluoropolyether oil and 4% of a nano-Al2O3 particle dispersion modified with a silane coupling agent KH-550; the ester lubricant has a viscosity of 8-12 mm at 40°C. 2 / s of pentaerythritol oleate; the composite rust inhibitor consists of 2% of benzotriazole derivatives and 1% of triethanolamine borate; the pH stabilizer is ammonium borate.

[0046] Comparative Example 1

[0047] A cutting fluid comprises, by mass percentage, 3% of a composite rust inhibitor, 1% of a pH stabilizer, and the balance deionized water; the composite rust inhibitor is composed of 2% of a benzotriazole derivative and 1% of triethanolamine borate; and the pH stabilizer is ammonium borate.

[0048] Comparative Example 2

[0049] A cutting fluid comprises, by mass percentage, 8% of a binary composite coolant, 3% of a composite rust inhibitor, 1% of a pH stabilizer, and the balance deionized water; the binary composite coolant is composed of 5% of perfluoropolyether oil and 3% of a dispersion of nano-Al2O3 particles surface-modified with a silane coupling agent KH-550; the composite rust inhibitor is composed of 2% of a benzotriazole derivative and 1% of triethanolamine borate; and the pH stabilizer is ammonium borate.

[0050] Comparative Example 3

[0051] A cutting fluid, wherein the composition comprises, by mass percentage, 12% of an ester lubricant, 3% of a composite rust preventive, 1% of a pH stabilizer, and the balance of deionized water; the ester lubricant has a viscosity of 8-12 mm at 40°C. 2 / s of pentaerythritol oleate; the composite rust inhibitor consists of 2% of benzotriazole derivatives and 1% of triethanolamine borate; the pH stabilizer is ammonium borate.

[0052] Comparative Example 4

[0053] A cutting fluid, wherein the composition comprises, by mass percentage, 8% of a binary composite coolant, 12% of an ester lubricant, 3% of a composite rust preventive, 1% of a pH stabilizer, and the balance deionized water; the binary composite coolant is composed of 6% of a perfluoropolyether oil and 2% of a nano-Al2O3 particle dispersion modified with a silane coupling agent KH-550; the ester lubricant has a viscosity of 8-12 mm at 40°C. 2 / s of pentaerythritol oleate; the composite rust inhibitor consists of 2% of benzotriazole derivatives and 1% of triethanolamine borate; the pH stabilizer is ammonium borate.

[0054] Comparative Example 5

[0055] A cutting fluid, wherein the composition comprises, by mass percentage, 8% of a binary composite coolant, 12% of an ester lubricant, 3% of a composite rust preventive, 1% of a pH stabilizer, and the balance deionized water; the binary composite coolant is composed of 4% of a perfluoropolyether oil and 4% of a nano-Al2O3 particle dispersion modified with a silane coupling agent KH-550; the ester lubricant has a viscosity of 8-12 mm at 40°C. 2 / s of pentaerythritol oleate; the composite rust inhibitor consists of 2% of benzotriazole derivatives and 1% of triethanolamine borate; the pH stabilizer is ammonium borate.

[0056] The specific composition of the cutting fluid formula is shown in Table 1.

[0057] Table 1 Cutting fluid formula experimental group design

[0058]

[0059] The cutting fluids prepared in Examples 1-2 and Comparative Examples 1-5 above were used for ultraprecision machining of pure tin. The experimental conditions are as follows: workpiece material: pure tin test block (Sn>99.9%, hardness HB 10-15); tool: carbide tap (M6, TiAlN coating); machining parameters: cutting test, speed 800 rpm, hole depth 10 mm, continuous machining of 2 holes / group (test repeated three times); experimental equipment: tapping torque tester, infrared thermometer, white light interferometer, SEM; the measured results are shown in Tables 2 and 3.

[0060] Table 2 Average torque and temperature rise test results

[0061]

[0062]

[0063] Table 3 Tapping torque test results

[0064]

[0065] As can be seen from the results in Table 2, Comparative Example 1, which does not contain the composite coolant and lubricant, achieves an average torque of 210 Ncm and a temperature rise of 18°C, comparable to the lubrication and cooling performance of traditional tin alloy cutting fluids. In Comparative Examples 2 and 3, the addition of the composite coolant and lubricant alone only slightly reduces the average torque and temperature rise. However, in Example 1 (5% PEPE + 3% Al2O3), after the composite coolant and lubricant were added simultaneously, the average torque was reduced by 40% (125 Ncm) and the temperature rise decreased by 56% (8°C) relative to Comparative Example 1. In Comparative Example 4 (6% PEPE + 2% Al2O3), the excessively high PEPE ratio resulted in insufficient nanoparticles, and the temperature rise was slightly higher (9°C) than in Example 1. In Comparative Example 5 (4% ​​PEPE + 4% Al2O3), the excessively high Al2O3 ratio caused slight particle agglomeration and a slight increase in torque (130 Ncm). By comparison, it was found that the optimal ratio of composite coolant PEPE: Al2O3 is 5%:3%, which can achieve a balance between phase change heat absorption and micro-ball effect, and has relatively better lubrication and cooling properties. In Example 2, after increasing the composite coolant to 10%, the performance is optimal (average torque 115Ncm, temperature rise 7°C), but the cost increases by 20%, and it is recommended for ultra-high precision scenarios. The 8% composite coolant in Example 1 has the highest cost-effectiveness and can meet the needs of conventional precision machining.

[0066] From the results in Table 3, it can be seen that in Comparative Example 1 (no cooling / lubrication): Ra=0.25 μm, there are obvious furrows and adhesion nodules on the surface (SEM observation), due to the lack of lubrication and cooling, the pure tin material undergoes severe plastic flow.

[0067] In Comparative Example 2 (coolant only): Ra = 0.15 μm, the temperature rise is well controlled (12° C.), but insufficient lubrication leads to local micro-area adhesion, and intermittent scratches are visible on the surface.

[0068] In Comparative Example 3 (lubricant only): Ra=0.18 μm, lubrication reduces adhesion, but a temperature rise of 15° C. causes thermal softening of the material, and the surface exhibits corrugated plastic deformation.

[0069] In comparative example 4 (PFPE ratio is too high), Ra=0.06 μm, PFPE accounts for 6%, resulting in only 2% nano-Al2O3, insufficient particle density, and discontinuous lubricating film in local areas.

[0070] In Comparative Example 5 (the proportion of Al2O3 is too high), Ra=0.06μm, and Al2O3 accounts for 4%, which causes particle agglomeration (DLS detection particle size>200nm), leaving micron-level scratches on the surface.

[0071] In Example 1 (8% coolant + 12% lubricant), Ra = 0.05 μm, achieving mirror-grade finish, due to: the PFPE isolation layer: blocks direct contact between the tool and the workpiece, inhibiting adhesion; the nano-Al2O3 micro-ball effect: reduces friction scratches; and the ester-based lubricating film: evenly covers the surface, inhibiting plastic deformation.

[0072] In Example 2 (10% coolant + 12% lubricant), Ra = 0.04 μm. The increase in the total amount of coolant enhances heat dissipation, but the cost-effectiveness ratio decreases, and it is only suitable for ultra-precision scenarios.

[0073] In summary, the surface roughness Ra of a pure tin workpiece machined using the cutting fluid of the present invention (Example 1) reached 0.05 μm, an 80% reduction compared to 0.25 μm in Comparative Example 1, with no adhesion or scratches. This effect stems from the synergistic effect of the composite coolant and the ester-based lubricant: PFPE inhibits interfacial adhesion, nano-Al₂O₃ reduces friction scratches, and the ester molecules form a continuous lubricating film. Furthermore, after immersing a tin alloy specimen (polished with P800 and P1200 sandpaper, respectively) in a 5% diluted solution of the present cutting fluid for 24 hours, the surface oxidation grade was Class A, demonstrating excellent corrosion inhibition.

[0074] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. An environmentally friendly pure tin ultra-precision machining cutting fluid, characterized in that: The invention comprises, by mass percentage, 8-13% of a binary composite coolant, 10-15% of an ester lubricant, 3-5% of a composite rust preventive, 0.5-1% of a pH stabilizer, and the balance of deionized water; the binary composite coolant is composed of 5-8% of a perfluoropolyether oil and 3-5% of a surface-modified nanoparticle dispersion; the ester lubricant has a viscosity of 8-12 mm at 40°C. 2 / s of pentaerythritol oleate.

2. The environmentally friendly pure tin ultra-precision machining cutting fluid according to claim 1, characterized in that: The perfluoropolyether oil is a linear structure with a molecular weight of 2000-3000 g / mol, a viscosity of 8-12 cSt at 40° C., and a surface tension of less than 20 mN / m.

3. The environmentally friendly pure tin ultra-precision machining cutting fluid according to claim 1, characterized in that: The surface-modified nanoparticle dispersion is a nanoparticle dispersion whose surface has been modified by a silane coupling agent, wherein the nanoparticles are one or more of α-phase Al2O3 particles, MoS2 particles, CuO particles and ZnO particles.

4. The environmentally friendly pure tin ultra-precision machining cutting fluid according to claim 3, characterized in that: The particle size of the nanoparticles is 50-100 nm.

5. The environmentally friendly pure tin ultra-precision machining cutting fluid according to claim 1, characterized in that: The composite rust preventive consists of 2-3% of benzotriazole derivatives and 1-2% of triethanolamine borate.

6. The environmentally friendly pure tin ultra-precision machining cutting fluid according to claim 1, characterized in that: The pH stabilizer is ammonium borate.

7. The environmentally friendly pure tin ultra-precision machining cutting fluid according to claim 1, characterized in that: The invention also comprises a corrosion inhibitor, which is one of nitrosobenzotriazole, phosphate and imidazole corrosion inhibitors.

8. A method for preparing an environmentally friendly pure tin ultra-precision machining cutting fluid, characterized in that: Including steps: Weighing by mass percentage 5-8% of perfluoropolyether oil, 3-5% of surface-modified nanoparticle dispersion, 10-15% of ester lubricant, 2-3% of benzotriazole derivative, 1-2% of triethanolamine borate, 0.5-1% of pH stabilizer, and the balance deionized water; Adding the perfluoropolyether oil and the surface-modified nanoparticle dispersion into an ultrasonic reactor for ultrasonic treatment to prepare a binary composite coolant; Heat the ester lubricant to 50-80°C, start the stirring device, slowly add the benzotriazole derivative, and continue the reaction for 10-30 minutes until the system becomes transparent to prepare the ester lubricant premix; Deionized water, binary composite coolant, and ester-based lubricant premix are sequentially added to the reactor, the temperature is controlled at 50-55°C, and triethanolamine borate and boric acid amine salt are added after stirring for 30-50 minutes. Finally, stirring and shearing emulsification are performed for 10-20 minutes to obtain a mixed solution. The mixed liquid is passed through a 5 μm precision filter to remove impurities, thereby preparing the environmentally friendly pure tin ultra-precision machining cutting fluid.

9. The method for preparing the environmentally friendly pure tin ultra-precision machining cutting fluid according to claim 8, characterized in that: Ultrasonic treatment refers to ultrasonic dispersion at 40-45°C for 20-40 minutes.

10. The method for preparing the environmentally friendly pure tin ultra-precision machining cutting fluid according to claim 8, characterized in that: After adding triethanolamine borate and boric acid amine salt, the pH of the system is adjusted to 8.5-9.2.

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