C60 nanofluid minimal quantity lubrication turning method for difficult-to-machine materials

Abstract

The invention discloses a C60 nanofluid minimal quantity lubrication turning method for a difficult-to-machine material, and belongs to a machining method. The cutter is especially suitable for cutting machining of difficult-to-machine materials. The nanofluid is prepared from fullerene C60 carbon nanospheres, trace lubricating oil based on plant components and a high-efficiency dispersing agent through accurate proportioning and a specific preparation process. The fullerene C60 carbon nanospheres can form a stable dispersion system in the cutting fluid due to the unique molecular structure and physicochemical properties, and exert excellent lubrication and antifriction effects in the cutting process. The trace lubricating oil has good biodegradability and environmental friendliness, and also has good lubricating performance and cooling performance. The dispersing agent ensures that the carbon nanospheres are uniformly dispersed in the cutting fluid, and agglomeration and precipitation are avoided. The nanofluid can remarkably improve the lubricating effect and cooling performance of cutting machining, reduce the cutting force and cutting heat, prolong the service life of a cutter and improve the machining quality and efficiency.

Description

Technical Field

[0001] The invention belongs to a mechanical processing method, and in particular relates to a C60 nanofluid micro-lubrication turning method for difficult-to-process materials. Background Art

[0002] When processing difficult-to-process materials, a large amount of cutting fluid is usually required to reduce cutting force and lower cutting temperature, which increases processing costs and poses a huge threat to the environment and human health.

[0003] Minimal Quantity Lubrication (MQL) is a green processing technology that mixes compressed air and a small amount of degradable environmentally friendly cutting fluid to form micron-sized droplets, which are then sprayed at high speed to the cutting area. The amount of cutting fluid used is about one ten-thousandth of traditional pouring lubrication, which greatly reduces processing costs and harm to the environment and health. However, when using MQL to cut difficult-to-cut materials, it is difficult for the cutting fluid droplets to form an effective lubricating film on the friction surface, resulting in a significant difference in cooling and lubrication effect from traditional pouring lubrication.

[0004] The spherical fullerene C60 molecule is an extremely strong and very stable molecule. It is the most symmetrical and round molecule found in three-dimensional space so far (the diameter of the sphere is about 7 nanometers). It has high compressive strength. Experiments have found that it can withstand a friction surface pressure of 7 GPa. It is also resistant to high temperatures and has strong thermal stability, so it has excellent lubrication properties.

[0005] A certain proportion of fullerene C60 nanocarbon balls is added to the MQL cutting fluid to form a C60 nanofluid. Compared with the original cutting fluid, its viscosity is increased, which improves the lubrication performance of the original cutting fluid. The prepared C60 nanofluid is used for micro-lubrication turning of difficult-to-process materials. The role of compressed air effectively improves the permeability of fullerene C60 nanocarbon balls to the cutting deformation zone. The fullerene C60 nanocarbon balls that penetrate into the cutting deformation zone play a "micro-bearing" effect between the contact surfaces, reducing the friction coefficient between the tool and the chips, and between the tool and the workpiece, thereby solving the problem of poor cooling and lubrication effect when MQL processes difficult-to-process materials. It also has the advantages of MQL, greatly reduces the amount of cutting fluid, and is energy-saving and environmentally friendly. Summary of the invention

[0006] The purpose of the present invention is to provide a C60 nanofluid micro-lubrication turning method for difficult-to-process materials, so that when turning various difficult-to-process materials, the cooling and lubrication effects are guaranteed, the life of the tool is extended, the lubrication cost can be reduced, the environmental pollution is reduced, and the health of the processing personnel is protected.

[0007] To achieve the above objectives, the present invention provides the following technical solutions.

[0008] A C60 nanofluid micro-lubrication turning method for difficult-to-machine materials comprises the following steps:

[0009] 1) Preparation of C60 nanofluid: According to the processing material, select the appropriate cutting fluid and then the appropriate dispersant. Mix the selected trace lubricant, dispersant and fullerene C60 nanocarbon balls in a certain proportion, and prepare the C60 nanofluid by mechanical stirring and ultrasonic dispersion;

[0010] 2) C60 nanofluid micro-lubrication turning: The C60 nanofluid and compressed air prepared in step 1) are introduced into their respective pipes, and the two pipes are connected to the same nozzle. The C60 nanofluid and compressed air are mixed and atomized at the nozzle and sprayed out of the nozzle toward the cutting processing area.

[0011] In step 1), the concentration ratio of the C60 nanofluid cutting fluid, dispersant and fullerene C60 nanocarbon spheres can be optimized by turning tests based on the actual material being processed, the selected cutting tool and other conditions.

[0012] The cutting fluid is a cutting fluid used for micro-lubrication and is harmless to humans and the environment. The cutting fluid can be CCF-40F micro-lubricating oil, the dispersant can be sodium dodecylbenzene sulfonate, and the fullerene C60 nano-carbon sphere can be commercially available fullerene C60.

[0013] Furthermore, the fullerene C60 nano-carbon spheres are selected from commercially available high-quality fullerene C60 nano-carbon spheres to ensure that their purity is higher than 99%, the particle size distribution is uniform, and the average particle size is between 10-50 nanometers;

[0014] The micro-lubricant uses CCF-40F micro-lubricant based on plant ingredients as the base fluid. This cutting fluid has good biodegradability and environmental friendliness, and also has good lubrication and cooling properties.

[0015] A high-efficiency micro-coupling agent is selected as a dispersant to ensure that the fullerene C60 nano-carbon spheres are evenly dispersed in the cutting fluid to avoid agglomeration and precipitation.

[0016] The concentration ratio of the fullerene C60 nano-carbon spheres, trace lubricating oil and dispersant is preferably obtained through turning experiments and is adjusted according to factors such as the actual processed material, the selected tool and cutting parameters.

[0017] In step 1), the mechanical stirring is controlled at a stirring speed of 500 to 1000 r / min, and the stirring time is not less than 30 min;

[0018] In step 1), the ultrasonic dispersion has an ultrasonic power controlled at 100 to 200 watts and a dispersion time of not less than 60 minutes.

[0019] In step 2), the nozzles are each connected with two pipes, one of which is connected with an oil tank filled with C60 nanofluid, and the other is connected with a compressed air cylinder.

[0020] A C60 nanofluid micro-lubrication turning method for difficult-to-process materials uses the fullerene C60 nanofluid as a micro-lubrication cutting fluid. During the cutting process, the C60 nanofluid and compressed air are simultaneously ejected through a nozzle. The C60 nanofluid is atomized to form micron-sized droplets under the action of the compressed air, and is sprayed toward the cutting process area at a high speed driven by the compressed air to cool and lubricate the processing process.

[0021] The cutting material is a difficult-to-cut material, such as a nickel-based alloy, the tool is a cemented carbide tool, and the cutting parameters include cutting speed, feed rate and cutting depth, which are adjusted according to specific processing requirements.

[0022] The C60 nanofluid can effectively reduce cutting force and cutting heat during cutting, extend tool life, and improve processing quality and efficiency, while having good environmental performance and human safety.

[0023] The present invention aims at the problems existing in the current micro-lubrication technology for processing difficult-to-process materials, and provides a nanofluid micro-lubrication turning method. The method adds fullerene C60 nano-carbon balls as additives into micro-lubrication cutting fluid to form C60 nano-fluid, and the viscosity of the formed C60 nano-fluid is improved compared with the original cutting fluid, so the C60 nano-fluid has better cutting lubricity, and compressed air is used to atomize the C60 nano-fluid, and the C60 nano-fluid droplets are sprayed at a high speed to the cutting processing area under the drive of the compressed air, thereby improving the permeability of the fullerene C60 nano-carbon balls to the cutting processing area, and using the rolling "micro-bearing" effect of the fullerene C60 nano-carbon balls between the contact surfaces of the tool and the workpiece, and the tool and the chips, the original friction effect form is changed by "rolling instead of sliding" (sliding friction is replaced by ball rolling friction), and the cutting force and cutting heat are effectively reduced; the cutting fluid used is harmless and environmentally friendly, and meets the green processing standards; the nano-fluid is atomized by compressed air and sprayed into the cutting processing area, while the cooling and lubrication are improved, the amount of cutting fluid is also reduced, and the processing cost of difficult-to-process materials is reduced.

[0024] Compared with the prior art, the present invention has the following outstanding advantages:

[0025] 1. Compared with other nanomaterials, the fullerene C60 nano-carbon spheres of the present invention can more effectively improve the viscosity of the MQL cutting fluid. The viscosity of the MQL cutting fluid is relatively low (dynamic viscosity is about 20 mPa·s), so that the lubricating film formed in the cutting process area is relatively thin, which leads to direct contact between the tool and the workpiece, and between the tool and the chips, aggravating the wear of the tool and affecting the quality of the processed surface. The C60 nanofluid formed by mixing the MQL cutting fluid and the fullerene C60 nano-carbon spheres in a specific ratio has a higher viscosity and can form a thicker lubricating film in the cutting process area, which helps to avoid direct contact between the tool and the workpiece, and between the tool and the chips, and reduce wear.

[0026] 2. Compared with other nanomaterials, the fullerene C60 nano-carbon spheres proposed in the present invention are football-shaped molecules composed of 60 carbon atoms with aesthetic symmetry, and have better thermal stability and compressive strength. Under the pushing and squeezing of the tool and the workpiece, the tool and the chips, the fullerene C60 nano-carbon spheres roll in a "micro-bearing" effect, converting the sliding friction between the tool and the workpiece, the tool and the chips into rolling friction between the tool, the workpiece, the chips and the C60 nano-carbon balls, thereby reducing the cutting force and cutting heat.

[0027] 3. Compared with traditional pouring lubrication, the C60 nanofluid micro-lubrication of the present invention is atomized under the action of compressed air and sprayed into the cutting deformation zone at high speed, which enhances the permeability of fullerene C60 nano-carbon balls to the cutting deformation zone, is more conducive to the formation of C60 nano-carbon ball lubrication film, and ensures the cooling and lubrication effect of the processing process. At the same time, the amount of C60 nanofluid used in the present invention is about one ten-thousandth of that in traditional pouring lubrication, which greatly reduces the processing cost. The cutting fluid used in the present invention is a plant-based cutting fluid specially used for micro-lubrication, which is more environmentally friendly and harmless to the human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the application of fullerene nanofluid minimal lubrication in the turning process of difficult-to-machine materials.

[0029] Figure 2 This is a schematic diagram showing the effect of fullerene nanofluid minimum quantity lubrication on three deformation zones during metal cutting.

[0030] Figure 3 This is a comparison chart of the effect of the concentration of fullerene C60 nanocarbon balls on the viscosity of C60 nanofluids.

[0031] Figure 4 This is a comparison chart showing the effect of particle size on the viscosity of alumina and titanium dioxide nanofluids with a nanoparticle mass fraction of 3%.

[0032] Figure 5 This is a comparison chart of the turning forces of nickel-based alloys under the conditions of minimal lubrication of the C60 nanofluid provided by the present invention, dry cutting, pouring lubrication without fullerene C60 additives, and minimal lubrication without fullerene C60 additives. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0034] The embodiment of the present invention first provides a fullerene C60 nanofluid, which is composed of fullerene C60 nanocarbon balls, a cutting fluid for micro-lubrication and a dispersant. When preparing the C60 nanofluid, it is necessary to mix the fullerene C60 nanocarbon balls, the cutting fluid for micro-lubrication and the dispersant in a certain proportion under normal temperature conditions, and then perform mechanical stirring and ultrasonic dispersion in succession. Among them, the concentration ratio of the fullerene C60 nanocarbon balls, the cutting fluid for micro-lubrication and the dispersant is preferably obtained by turning tests based on the actual processed materials, the selected cutting tools, etc.; the time required for mechanical stirring and ultrasonic dispersion is preferably obtained by performing C60 nanofluid preparation tests based on the selected cutting fluid and dispersant, and the concentration ratio of the components.

[0035] The C60 nanofluid cutting fluid is a plant-based lubricant specially used for minimal lubrication. Compared with traditional cutting fluids, it is more environmentally friendly and harmless to the human body and the environment.

[0036] The raw materials for preparing the C60 nanofluid are readily available and can be commercially available products. Among them, the cutting fluid used for micro-lubrication can be CCF-40F micro-lubricating oil, and the fullerene C60 nano-carbon spheres can be commercially available fullerene C60.

[0037] Compared with the original cutting fluid, the C60 nanofluid has a higher viscosity, which is more conducive to forming a lubricating oil film in the cutting area, avoiding direct contact between the tool and the workpiece and chips, thereby reducing cutting force, slowing down tool wear and ensuring the quality of the processed surface.

[0038] In this embodiment, the concentration of fullerene C60 nano-carbon balls is 300 ppm, and trace amounts of lubricating oil and dispersant are mixed in a certain proportion to ensure that the final C60 nanofluid has good lubrication performance and stability.

[0039] The present invention also provides a C60 nanofluid micro-lubrication turning method for difficult-to-machine materials, which is characterized in that the prepared C60 nanofluid is used as a micro-lubrication cutting fluid in the turning process of difficult-to-machine materials.

[0040] like Figure 1As shown, the compressed air cylinder and the machine tool oil tank filled with C60 nanofluid are connected to the air pipe and the oil pipe respectively, and finally connected to the same nozzle. The C60 nanofluid and compressed air pass through their respective pipes to the nozzle. The C60 nanofluid is atomized to form C60 nanofluid droplets under the action of compressed air, and is sprayed to the cutting processing area at a high speed driven by the compressed air to cool and lubricate the processing process.

[0041] The C60 nanofluid can effectively play a rolling "micro-bearing" effect between the turning tool and the chips, and between the turning tool and the workpiece, and has good friction reduction and anti-wear effects. Figure 1 As shown, the micron-sized droplets of C60 nanofluid atomized by compressed air penetrate into the turning processing area, and the C60 nanocarbon balls act as rolling bearings between the contact surfaces between the tool and the workpiece, and between the tool and the chips, converting the sliding friction between the tool and the workpiece, and between the tool and the chips into rolling friction between the tool, the workpiece, the chips and the C60 nanocarbon balls, thereby reducing the cutting force and cutting heat.

[0042] The C60 nanofluid is atomized under the action of compressed air and sprayed into the cutting deformation zone at high speed, which can effectively enhance the permeability of the fullerene C60 nanocarbon balls to the cutting deformation zone, is more conducive to the formation of the C60 nanocarbon ball lubrication film, and enhances the cooling and lubrication effect of the machining process.

[0043] The following embodiments will describe the present invention in detail by taking nickel-based alloy turning as an example in conjunction with the accompanying drawings. The examples of the embodiments are intended to explain the present invention and should not be construed as limiting the present invention.

[0044] Fullerene C60 nano carbon spheres, CCF-40F trace lubricant and trace coupling agent are mixed in a certain proportion, and mechanical stirring and ultrasonic dispersion are performed successively to prepare C60 nano fluid.

[0045] Figure 2 This is a schematic diagram showing the effect of fullerene nanofluid minimum quantity lubrication on three deformation zones during metal cutting.

[0046] The working principle of the present invention is as follows: the mixing of fullerene C60 nano carbon balls with MQL cutting fluid to prepare C60 nano fluid will increase the viscosity of the original cutting fluid, and it is easy to form a C60 nano fluid lubricating film on the cutting area. Fullerene C60 nano carbon balls are football-shaped hollow symmetrical molecules with 30 carbon-carbon double bonds (C=C) formed by 60 carbon atoms connected by 20 six-membered rings and 12 five-membered rings. They have high compressive strength and can withstand a friction surface pressure of several hundred GPa after a static pressure friction test; and fullerene C60 nano carbon balls are resistant to high temperatures, and their carbon cage structure molecules have high thermal stability, with a melting point of more than 3000°C. Under the extrusion of the workpiece and the tool, and the tool and the chips, the C60 nano carbon balls will roll, thereby converting the original sliding friction in the cutting deformation zone into rolling friction, effectively reducing the friction. Based on this, C60 nanofluid is used as cutting fluid for minimal lubrication turning. Under the action of compressed air, the C60 nanofluid is atomized and sprayed into the cutting area at high speed, which enhances the permeability of fullerene C60 nanocarbon balls into the cutting deformation zone, is beneficial to the formation of C60 nanofluid lubrication film, improves the cooling and lubrication effect of the machining process, and also reduces the amount of fullerene C60 nanofluid.

[0047] like Figure 3 As shown in the figure, with the increase of the concentration of fullerene C60 nanocarbon balls, the viscosity of C60 nanofluid increases. From 0ppm to 200ppm, the viscosity increases by about 5mPa·s for every 100ppm increase. From 200ppm to 400ppm, the viscosity increases by about 10mPa·s for every 100ppm increase. Figure 4 As shown in the figure, when the nanoparticle size of alumina and titanium dioxide nanofluids is 50nm, the viscosity of the nanofluid is the largest, but the effect of alumina and titanium dioxide nanoparticles on the viscosity of the cutting fluid is very small. When the nanoparticle size is 50nm and the mass fraction is 3%, the viscosity of the alumina nanofluid is about 4mPa·s higher than that of the original cutting fluid, and the viscosity of the titanium dioxide nanofluid is about 7mPa·s higher than that of the original cutting fluid. It can be seen that fullerene C60 nanocarbon spheres have a greater effect on the viscosity of the cutting fluid than nanomaterials such as alumina and titanium dioxide.

[0048] The prepared C60 nanofluid is added into the lathe oil tank. The workpiece material is a nickel-based alloy with low thermal conductivity, high hardness and high toughness. Figure 1 and 2 As shown in the figure, during the turning process of nickel-based alloy, C60 nanofluid droplets are driven by compressed air to spray at high speed between the tool and the chips, and between the tool and the workpiece, enhancing the permeability of C60 nanocarbon balls to the deformation zones II and III, thereby forming a C60 nanofluid lubrication film. The C60 nanocarbon balls play a "micro-bearing" effect and convert the sliding friction between the workpiece, chips and turning tool into rolling friction, thereby reducing the cutting force and cutting heat.

[0049] The turning process parameters of nickel-based alloy are shown in Table 1:

[0050] Table 1 Ni-based alloy turning process parameters

[0051]

[0052] The turning force comparison chart under dry cutting, pouring lubrication without fullerene C60 additive, minimum lubrication without fullerene C60 additive, and C60 nanofluid minimum lubrication conditions is shown in the figure. Figure 5 As shown. It can be seen that the use of fullerene C60 nanofluid for minimal lubrication can effectively reduce cutting force, not only reduce tool wear to prolong its service life and improve workpiece processing accuracy, but also reduce the amount of fullerene C60 nanocarbon balls and cutting fluid, reduce processing costs, reduce environmental pollution, and ensure the health of processing personnel.

[0053] The above is only a preferred specific implementation of the present invention, but the design concept of the present invention is not limited to this. Any technician familiar with the technical field who uses this concept to make non-substantial changes to the present invention within the technical scope disclosed by the present invention shall be deemed to infringe the protection scope of the present invention.

Claims

1. A fullerene C60 nanofluid, characterized in that: It consists of fullerene C60 nano-carbon balls, trace lubricating oil and dispersant; the purity of the fullerene C60 nano-carbon balls is higher than 99%, and the average particle size is 10-50nm; the trace lubricating oil uses CCF-40F trace lubricating oil based on plant ingredients as the base liquid; the dispersant uses a high-efficiency trace coupling agent as the dispersant to ensure that the fullerene C60 nano-carbon balls are evenly dispersed in the cutting fluid to avoid agglomeration and precipitation.

2. A fullerene C60 nanofluid according to claim 1, characterized in that: The concentration ratio of the fullerene C60 nano-carbon spheres, trace lubricating oil and dispersant is preferably obtained through turning tests and is adjusted according to the actual processed material, selected cutting tools and cutting parameters.

3. The fullerene C60 nanofluid according to claim 1, characterized in that: The dispersant is sodium dodecylbenzene sulfonate.

4. The method for preparing a fullerene C60 nanofluid according to claim 1, characterized in that: The specific steps are: mixing fullerene C60 nano carbon balls, a trace amount of lubricating oil and a dispersant according to required proportions; performing mechanical stirring and then performing ultrasonic dispersion to obtain the fullerene C60 nano fluid.

5. The method for preparing a fullerene C60 nanofluid according to claim 4, characterized in that The stirring speed of the mechanical stirring is controlled at 500-1000 r / min, and the stirring time is not less than 30 min.

6. The method for preparing a fullerene C60 nanofluid according to claim 4, characterized in that The ultrasonic power of the ultrasonic dispersion is controlled at 100 to 200 watts, and the ultrasonic dispersion time is not less than 60 minutes.

7. A C60 nanofluid micro-lubrication turning method for difficult-to-machine materials, characterized in that: The fullerene C60 nanofluid described in claim 1 is used as a micro-lubricating cutting fluid. During the cutting process, the fullerene C60 nanofluid and compressed air are simultaneously ejected through a nozzle. The fullerene C60 nanofluid is atomized to form micron-sized droplets under the action of compressed air, and is sprayed toward the cutting process area at a high speed driven by the compressed air to cool and lubricate the processing process. The fullerene C60 nanofluid can effectively reduce cutting force and cutting heat during the cutting process, extend tool life, and improve processing quality and efficiency.

8. The C60 nanofluid micro-lubrication turning method for difficult-to-machine materials according to claim 7, characterized in that: The material to be cut is a difficult-to-cut material and can be selected from nickel-based alloys. The tool is a cemented carbide tool. The cutting parameters include cutting speed, feed rate and cutting depth, which are adjusted according to specific processing requirements.

9. The C60 nanofluid micro-lubrication turning method for difficult-to-machine materials according to claim 7, characterized in that: The nozzles are each connected with two pipes, one of which is communicated with an oil tank filled with C60 nanofluid, and the other is communicated with a compressed air cylinder.

Images