KR101730378B1 - Oil film forming process and device using coupled magnetic nanoparticle jet stream and magnetic force workbench - Google Patents

Abstract

1. An oil film forming apparatus using a magnetic nanoparticle jet and a magnetic force workbench coupling, the apparatus comprising a magnetic force workbench (1), the workpiece (2) being attached to the upper part by a magnetic force, The nozzle 8 is placed at a position where the grinder cover 3 and the workpiece 2 match with each other and the nozzle 8 is placed at the position where the magnetic nanofluid transportation tube (5), connected to the air compressor by a compressed air delivery pipe (6), and the magnetic nanofluid and compressed air are mixed and accelerated in a nozzle (8) The three-phase fluid spray is introduced into the grinding section between the workpiece 2 and the grinder 4, and the magnetic force workbench and the three- Coupling As, the oil film is formed on the workpiece (2) surface. By transporting the magnetic nanoparticle fluid to the nozzle 8 and forming a lubricating oil film on the workpiece surface with the magnetic workbench 1, maximum cooling and lubrication effects are achieved in the grinding zone.

Description

TECHNICAL FIELD [0001] The present invention relates to an oil film forming process and apparatus using a magnetic nanoparticle jet and a magnetic force workbench coupling,

The present invention relates to an oil film forming process and apparatus using magnetic nanoparticle jets and magnetic workbench couplings.

Minimal Quantity Lubrication (MQL) is the process of mixing and atomizing a minimum amount of lubricant with compressed air at a constant pressure and spraying it to the grinding zone to form a contact between the grinder and the abrasive particles, the grinder and the workpiece This is a technology that promotes effective lubrication. The technology uses a minimum amount of grinding fluid (only about 0.001% of the capacity used in the conventional lubrication method) that ensures effective lubrication and cooling, thereby reducing costs and reducing environmental and human health hazards .

The nano-jet minimum lubrication is based on the theory of heat transfer strengthening. According to the theory of heat transfer enhancement, the heat transfer ability of solids is superior to that of liquids and gases. The thermal conductivity of a solid material at room temperature is much greater than that of a fluid material. The addition of solid particles to the minimum amount of lubricant medium can significantly compensate for the lack of minimum lubrication cooling capacity because the thermal conductivity of the fluid medium is significantly increased and the heat transfer capability to the fluid is improved. In addition, nanoparticles (ultrafine solid particles having a size of 1 to 100 nm) have frictional properties such as specific wear inhibiting ability and bearing capacity in terms of lubrication and friction. The minimum amount of nano-jet lubrication is to add nano-sized solid particles to a minimal amount of lubrication fluid to produce nanofluids, ie, mix and spray nanoparticles and lubricants (oil or oil and water mixture) and high- Spray in the area.

The inventors systematically conducted in-depth theoretical analysis and experiment verification of the minimum amount of lubricant grinding, and filed a patent application for the research results. The patent 201210153801.2 relates to a nanoparticle jet minimum amount lubricating grinding lubricant supply system, wherein nanosized solid particles are added to a decomposable grinding fluid to produce a lubricant of minimal amount of lubricating grinding, The droplet diameter is switched to the unchanging pulse droplet and the jet is jetted into the grinding zone in the jet type under the action of the air quenching layer produced by the high pressure gas. The present invention has all the advantages of a minimum amount of lubrication technology, and has more powerful cooling performance and excellent frictional characteristics, thereby improving workpiece surface quality. In addition, it has a high work efficiency, low energy consumption, At the same time, it is meaningful because it is possible to produce environmentally friendly low carbon green clean production.

The patent 201210490401.0 relates to a method and apparatus for predicting the roughness of a grinding surface under a minimum amount of lubricating conditions of a nanoparticle jet. The stylus is in contact with the grinder surface, the right end of the sensor lever is connected to the inductive displacement sensor, and the sensor lever is supported by the supporting portion of the sensor lever. The sensor lever includes a sensor lever, a stylus is attached to the left end of the sensor lever, The inductive displacement sensor is connected to an AC power source, the inductive displacement sensor data output is connected to a filter amplifier, the filter amplifier is connected to a computer and an oscilloscope, and the computer is connected to a memory Lt; / RTI > Since the present invention uses a grinder type of matrix characteristic and generates a mechanism according to the surface shape of the grinding workpiece again, the accuracy of the prediction model is high and it is easy to measure, as well as the facility density and the utilization rate are both high. In addition, the measurement precision is high and the reliability is high, which has a substantial meaning.

The patent 201110221543.2 relates to a nanoparticle jet minimum flow lubricating grinding three-phase fluid supply system in which the nanofluid is transported to the nozzle point via the liquid path while at the same time the high pressure gas enters the nozzle via the gas path, And the nanofluid is sufficiently mixed and atomized in the nozzle mixing chamber, accelerated through the acceleration chamber, and then enters the swirl chamber. At the same time, the compressed gas enters the vent hole through the swirl chamber, and the three- Afterwards, the three-phase fluid is ejected to the grinding zone through the nozzle exit in droplet atomization format.

However, all of the conventional techniques have changed the viscosity of the nanofluids and the adhesion of the nanoparticles and the workpiece surface under the coupling action of the magnetic nanoparticles and the magnetic workbench, allowing the nanoparticles to participate in the heat transfer enhancement within a larger limit The lubrication between the grinder and the workpiece surface is reduced to reduce the oil film friction and effectively reduce the drift loss of the nanofluid droplet, thereby failing to realize a low-carbon clean, high-efficiency, minimum amount of lubrication grinding.

Although many scholars have already conducted theoretical analysis and experimental verification of nano-minimum lubrication, they have not been able to organically link the magnetic nanoparticle jet minimum lubrication with the grinding machine magnetic workbench. In addition, because of the inability to establish the intrinsic relationship between the formation of the lubricating oil film and the magnetic nanoparticles and magnetic force workbenches, and the mechanism between the magnetic nanoparticles and the oil films on the magnetic workbench workpiece surface, the magnetic nano- And to cause lubrication and heat dissipation at the workpiece interface.

In order to solve the above problems, the present invention proposes an oil film forming process and apparatus using a magnetic nanoparticle jet and a magnetic workbench coupling. The present invention utilizes magnetic nanoparticle jet minimum lubrication and magnetic force workbench coupling action in the field of grinding to transport the magnetic nanoparticle fluid to the nozzle and the magnetic nanoparticle fluid is compressed at a relatively high rate into the grinding zone By forming a lubricating oil film on the surface of the workpiece with the magnetic workbench being sprayed, maximum cooling and lubrication effects are achieved in the grinding zone.

To achieve the above object, the present invention adopts the following technical solution.

CLAIMS 1. An oil film forming apparatus using a magnetic nanoparticle jet and a magnetic force workbench coupling, the apparatus comprising a magnetic force workbench, wherein the workpiece is attached to the top of the magnetic force work bench by a magnetic force, Wherein the nozzle is mounted at a machining position of the workpiece, the nozzle being seated at a position where the grinder cover and the workpiece match, the nozzle being connected to the magnetic nanofluid liquid supply device by a magnetic nanofluid transportation pipe, The magnetic nanofluids and the compressed air are mixed and accelerated in the nozzle, and then the three-phase fluid is sprayed, and the compressed air, the magnetic nanoparticles and the grinding fluid base particles are mixed and sprayed, and the three- Into the grinding section between the piece and the grinder, and the magnetic force workbench and the three- By a magnetic coupling, the oil film on the workpiece surface is formed.

Wherein the magnetic force workbench is an electromagnetic work bench including a lower attracting plate body and an upper lid plate, wherein a core is disposed in the attracting plate body, a coil is wound around the core body, the coil is connected to a power control circuit, Wherein a plurality of magnetic layers are provided on the cover plate and the cover plate is divided into a plurality of small blocks to form a distribution pattern separated from the N pole and the S pole, To return to the adsorbent, not the cover plate, thereby constituting a complete magnetic circuit.

The anti-magnetic layer is made of a non-magnetic material of babbitt metal and has a width c of 2.0 to 4.5 mm.

의 관계가 성립한다.And the N-pole blocks and the S pole block total number is an odd number, each of the N-pole blocks, were the width of the S pole blocks are the same, the N-pole single-plate width h _1, the N pole block width h ₃ and the S pole width h ₂ Between

.

Wherein the power control circuit comprises a single chip computer management unit, wherein the single chip computer management unit is coupled to an optoelectronic connection silicon controlled rectifier (SCR) zero crossing control AC switch unit, Wherein the crossing control AC switch unit is connected to a rectification filter unit, the rectification filter unit is connected to an overload automatic prevention unit, the overload automatic prevention unit is connected to an arcless voltage polarity switching control unit, The polarity switching control unit outputs an operating voltage to the coil, the optoelectronic connection SCR zero crossing control AC switch unit is connected to an AC power transformer, the AC power transformer is connected to a commercial frequency power circuit input, The unit is also connected to a continuous variable voltage input control unit, Group continuously variable input voltage control unit is connected to the opto-electronic connection SCR zero crossing control switch AC unit, the single-chip computer management unit is connected to the non-arc voltage polarity switching unit is an element (demagnetization) circuit.

The nozzle and the workpiece distance d are 10 to 25 cm, and the narrow angle a of the nozzle and the workpiece is 15 to 45 degrees.

In a film forming process of an oil film forming apparatus using a magnetic nanoparticle jet and a magnetic force workbench coupling,

The magnetic force workbench comprises the steps of: 1) adsorbing and fixing a workpiece on a surface, and placing the grinder at a processing position on the workpiece;

Spraying a three-phase fluid spray formed by the magnetic nanofluid and compressed air to the grinding zone between the workpiece and the grinder when the grinding is started;

The magnetic field of the workpiece surface causes the magnetic nanoparticles to move along a line of magnetic force, the magnetic nanoparticles enhance the adsorption capability of the workpiece surface, and when the friction between the grinder and the work surface occurs, Step 3 being formed;

And a step 4 of waiting for the machining to be completed and proceeding with the elements of the magnetic force workbench.

The injection flow rate of the nozzle is 2.5 to 5.5 ml / min, and the pressure of the compressed air is 4.0 to 10 bar.

In the magnetic nanofluid, the particle size of nanoparticles is equal to or smaller than 100 nm, and the content of the nanoparticles is 1 to 30 vol%.

The present invention has the following advantages. The present invention prevents the environment and the human body from being damaged due to the drift of fine particles during spraying, because the magnetic nanofluids sprayed on the surface of the workpiece are attracted to the magnetic nanoparticles using the adsorption action of the magnetic field. , The nanoparticle adsorption force on the surface of the workpiece is strengthened, so that an oil film can be formed more easily to cause lubrication and heat dissipation. The present invention has all the advantages of a minimal amount of lubrication machining technology and has a strong cooling performance and excellent frictional properties when the magnetic nanoparticles are adsorbed on the workpiece surface above the magnetic workbench, It is possible to improve the quality of the workpiece surface and to achieve low-carbon green production such as high efficiency, low energy consumption, environment friendliness and resource saving.

1 is a final assembly shaft side view of an embodiment;
2 is a system circuit diagram of a liquid path and a gas path of an embodiment;
3 is an explanatory view of a magnetic force work bench operating principle of the embodiment;
Fig. 4 is a valve body structure diagram of the embodiment; Fig.
5 is a structural view of a cover plate of an embodiment;
FIG. 5A is an AA sectional view in FIG. 5; FIG.
FIG. 5B is a cross-sectional view taken along line BB in FIG. 5;
5c is a CC sectional view in Fig. 5; Fig.
FIG. 5D is a DD sectional view in FIG. 5; FIG.
6 is a block diagram of a power supply control principle block of the embodiment;
7 is an explanatory diagram of a relative position between a nozzle and a workpiece in the embodiment;
FIG. 8 is an explanatory view of an oil film formed by general nano particle lubrication in the embodiment; FIG.
Fig. 9 is an oil film explanatory view formed by magnetic nanoparticle lubrication in an external magnetic field in the embodiment; Fig.
10 is a graph showing a relationship between different lubrication conditions and friction coefficients in the experiments of the embodiment;
11 is a graph showing the relationship between the different lubrication conditions and the diameter of the friction mark in the experiment of the embodiment;
12 is a graph showing a relationship between different lubrication conditions and a grinding zone peak temperature in the experiment of the embodiment.

Hereinafter, the present invention will be described in detail with reference to the drawings.

As shown in the entire assembling shaft side view of the embodiment in Fig. 1, the above-described embodiment describes the process during grinding. As can be seen from the drawing, the fitting device is not mounted on the magnetic force workbench 1, and the workpiece 2 is fixed to the magnetic force workbench 1 by the electromagnetic force. In the magnetic nanofluid minimum lubrication system adopted in the lubrication system, the magnetic nanofluid and the compressed air enter the nozzle 8 by the magnetic nanofluid transportation pipe 5 and the compressed air transportation pipe 6, respectively, 8) to form a three-phase fluid spray (compressed air, a mixed spray of solid magnetic nanoparticles and grinding fluid base particles). The Samsung fluid spray injected from the nozzle 8 can enter the grinding zone between the workpiece 2 and the grinder 4. Here, the magnetic nanofluid transportation pipe 5 and the compressed air transportation pipe 6 are fixed to the grinder cover 3 by using the magnetic force attraction plate 7.

Figure 2 shows a liquid and gas supply system in an embodiment. As can be seen in the figure, the gas path comprises an air compressor 14, a filter I 16, a gas storage tank 19, a pressure regulating valve I 22, a throttle valve I 23 and a turbine flow meter I (25), and finally connected to the nozzle (8). Here, the pressure gauge III 20 is used to monitor the pressure in the gas storage tank 19 and the pressure gauge I 28 is used to monitor the gas path outlet pressure to ensure the required air pressure. The liquid path consists of a main liquid path and a protection circuit wherein the main liquid path is the magnetic nanofluid liquid storage tank 15, the filter II 17, the hydraulic pump 18, the pressure regulating valve II 21, The valve II 24 and the turbine flowmeter II 26 are connected in order and finally connected to the nozzle 8. Where the pressure gauge II 27 is used to monitor the liquid path outlet pressure. The protection circuit comprises a relief valve (29) and a magnetic nanofluid recovery box (30).

FIG. 3 shows the principle of operation of the magnetic force workbench and is based on the electromagnetic effect principle. The core 11 formed by superimposing the silicon steel sheet is wrapped with the coil 12 and electromagnetism is formed according to the principle of electromagnetic effect when electricity is passed through the coil 12, Stimulation is distributed. The magnetic force lines pass through the core 11 and pass through the N pole magnetic block and the work piece 2 of the cover plate 9 and again through the bipolar magnetic block of the cover plate 9, the attracting plate 10, And is absorbed by the workpiece 2. In this case, The width c of the magnetic layer 13 is generally 2.0 to 4.5 mm and the magnetic layer 13 separates the cover plate 9 into a part of a small block, And the S pole are spaced apart. The magnetic layer 13 constitutes a complete magnetic circuit because most of the magnetic force causes the workpiece 2 to return to the adsorption plate 10 instead of the cover plate 9. [ When the current of the coil is increased, the magnetic field strength becomes strong, and the magnetic line of force is closed by the workpiece, so that the workpiece becomes magnetized.

Fig. 4 relates to the plate structure of the above embodiment, in which the workbench is used as a single-coil electromagnetic workbench, in which the position of the coil can be known. The size of the core 11 is d ₁ xb _1, d ₁ is the core length, b ₁ is the core width. When viewed in conjunction with Figure 3, after completion of the dip coating of the coil was placed in the coil groove coil groove size it is d ₂ xb _2, d ₂ it can be seen that the coil groove length, the groove width b ₂ is a coil. The peripheral gap distance is 3 to 8 cm as shown in Figs. 3 (a) and 3 (b), and is prepared for asphalt injection, and there is also a fine gap between the coil 12 and the core 11. The size of the adsorption plate is d ₃ xb ₃ , d ₃ is the adsorption plate length, and b ₃ is the adsorption plate width. The size of the coil groove can be determined according to the number of turns of the designed coil and the conductor diameter. The distribution of internal threads connected to the cover plate 9 is as shown in the figure.

와 같은 관계가 성립한다.FIG. 5 is a view for explaining the structure of the cover plate of the embodiment. As shown in the figure, the N pole piece 31 and the S pole piece 32 are interphase distributed, Lt; / RTI > Diagram BB is a cross-sectional view of the N pole piece 31, AA is a cross section of the S pole piece 32, DD is a cross section of the N pole plate 33, . As shown in each sectional view, the N pole piece 31 is connected only to the attracting plate 10, the S pole piece 32 is connected only to the core 11, and the middle is isolated by the anti-magnetic layer 13 The N pole piece 34 is hingedly connected to the N pole piece 34 in order so that the N pole piece S, the N pole piece piece 33, the N pole piece piece 31, the S pole piece piece 32 and the anti- This shows the distribution of stimuli between polar phases. The widths of the N pole piece 31 and the S pole piece 32 can be determined by calculation according to the size of the machine tool when designing the machine tool and the N pole piece 31 and the S pole piece 32 The width of each of the N pole piece 31 and the S pole piece 32 is the same and the width of the N pole plate 33 is h ₁ and the width of the N pole piece 31 is h ₃ And the width h ₂ of the S pole piece 32

And so on.

FIG. 6 is a block diagram of a power supply control principle block of the embodiment, and is characterized by microcontroller management, photoelectric connection, pulse width modulation, SCR AC zero crossing switch automatic short circuit prevention, and arc free spark voltage polarity switching do.

The power supply control circuit includes a single-chip computer management unit 40, the single-chip computer management unit 40 is connected to an optoelectronic connection SCR zero crossing control AC switch unit 41, an optoelectronic connection SCR zero crossing control AC switch unit Arc voltage polarity switching control unit 44 is connected to the rectification filter unit 42. The rectification filter unit 42 is connected to the overload automatic prevention unit 43 and the overload automatic prevention unit 43 is connected to the non- Arc voltage polarity switching control unit 44 outputs the operating voltage to the coil, the optoelectronic connection SCR zero crossing control AC switch unit 41 is connected to the AC power transformer 36, and the AC power transformer 36 are connected to a commercial frequency power supply circuit input 35 and the single chip computer management unit 40 is also connected to a continuous variable voltage input control unit and the continuous variable voltage input control unit is connected to a photoelectric connection SCR zero Rosing is connected to the control exchange switch unit 41, a single-chip computer management unit 40 is connected to the non-arc voltage polarity switching unit 44 to samneunda element (demagnetization) circuit.

The circuit is provided with a continuous variable voltage input control unit module 46 to realize continuous variable DC voltage output and is capable of performing external operation of the single chip computer managing unit 40 based on the mode of the single chip computer managing unit 40 You can enter the required DC voltage value on the panel. Changes in DC voltage can affect the film forming and cooling characteristics of the magnetic nano-jet because it can change the current together and eventually change the magnetic field strength of the magnetic force workbench. After the machining is finished and the power supply is interrupted, the element switch 39 can be connected and the rectifying filter unit 42 can be converted into the converted direct current polarity through the arcless spark voltage polarity switching unit 44. [ Therefore, the object of the device can be achieved by supplying the counter voltage to the workbench, and the specific procedure is as follows.

The specific working process of the present invention is as follows.

Minimal lubrication is a lubrication processing technique that has become increasingly known to people since it was developed several years ago. The minimum amount of lubrication grinding is a cooling lubrication method in which compressed air and a minimum amount of grinding liquid are mixed, atomized and then injected into the grinding section through a nozzle. The minimum amount of lubrication can reduce the use of grinding fluid as much as possible, thus effectively reducing the effects of grinding fluid on the environment and human health, as well as being environmentally friendly green manufacturing technology. However, the minimum amount of lubrication often degrades the quality of the machined surface and may even lead to abrasive wear and tear. Some scholars have added nanoparticles to the grinding fluid based on the theory of heat transfer enhancement, which is what appears to be the nano-minimum amount of lubrication. The lubrication system effectively solves the problems of the prior art. However, in the grinding process, the amount of energy required to remove a single material volume was much larger than in other cutting methods, resulting in a large amount of heat in the grinding zone. Excessive grinding temperatures affect the quality of the machined surface and the service life of the grinder, as well as reduce the performance of the lubricant.

As the temperature rises, the viscosity of the grinding fluid drops, which affects the ability of the grinding fluid to form on the machined surface, which in turn reduces the thickness and supportability of the lubricating oil film. Since the viscosity of the grinding liquid is lowered and the fluidity is increased, the oil film can be easily damaged when the grinder and the workpiece come in contact with each other. When the oil film is damaged, friction occurs on the grinder and the surface of the workpiece, and the temperature of the grinding zone rises sharply, which not only has considerable adverse effects on the grinding process but also causes a vicious circle .

In order to solve the above-mentioned problem of the minimum amount of nano-lubrication, in the present invention, magnetic nanoparticles (inducing magnetism and expressing magnetic nanoparticles in an external magnetic field action) are added to a grinding liquid to form a micro magnetic fluid And proposed a technique to form an oil film with excellent lubricating heat dissipation performance on the machined surface by conducting a coupling with a magnetic force workbench.

As the nanomaterial develops, the types of magnetic nanoparticles currently studied include -Fe ₂ O ₃ nanoparticles, Fe ₃ O ₄ nanoparticles, Fe ₃ N ₄ nanoparticles, Fe-Co nanoparticles, Ni-Fe nanoparticles, MnZnFe ₂ O ₄ and so on.

The magnetic nanofluids (the solution of the magnetic nanoparticles mixed with the grinding base oil according to a certain mixing ratio) enter the nozzle 8 through the liquid path while the compressed gas enters the nozzle 8 through the gas path. The magnetic nanofluid and the compressed air are mixed and accelerated in the nozzle 8 and then injected. The distance d between the nozzle 8 and the workpiece 2 is 10 to 25 cm and the nozzle angle a is 15 to 45. The relative positions of the nozzle 8 and the workpiece 2 are shown in Fig. Same as. The injection flow rate of the nozzle 5 is 2.5 to 5.5 ml / min and the pressure of the compressed air is 4.0 to 10 bar. The particle size of the nanoparticles is smaller than or equal to 100 nm, and the content of the nanoparticles is 1 to 30 vol%.

In this embodiment, the average attracting force F of the magnetic force workbench is 10 kg / cm ² , the minimum attraction force is 7 kg / cm ² , the maximum attraction force is 13 kg / cm ² , the number of turns of the coil is 2700, 1.56 mm, and a diameter of 1.67 mm after patent leather processing. The workbench material is quenched Q235 steel and the antimagnetic layer material is bibit metal. Further, the magnetic force intensity of the workbench varies with the voltage, specifically, the following.

According to Ohm's law,

I _W = H∫

이며, 즉 전류 I와 자기유도 B는 정비례한다. 여기에서 알 수 있듯이, 자기회로의 전류 크기를 바꾸면 자기유도 강도를 변화시킬 수 있기 때문에, 필요한 자기장 강도와 자성 나노 입자 커플링을 보장할 수 있다.Where I _W is the product of the current I and the number of turns, I _W = I × w, H is the magnetic field strength (ampere count / cm ² ), and ∫ is the magnetic circuit length. Also, there is the formula B = μH × 10 ⁸ , where B is the magnetic induction (Gauss) and μ is the magnetic induction coefficient (H / cm). therefore

That is, the current I and the magnetic induction B are in direct proportion. As can be seen, changing the magnitude of the current in the magnetic circuit can change the magnetic induction intensity, thus ensuring the required magnetic field strength and magnetic nanoparticle coupling.

According to Maxwell's law,

이다.Where F is the electromagnetic force (J / cm), B is the magnetic induction (Wb / cm ² ), S is the total surface area of the stimulating surface (cm ² ), μ ₀ is the air induction coefficient (1.25 x 10 ^-2 H / , B is Gauss when F is the gravity of kg, and S = 1 is substituted

to be.

가 도출되고, 상기 식에서 전류와 워크벤치 흡인력의 관계를 알 수 있다. 즉, 전류가 커지면 워크벤치 흡인력도 커진다.Taken together,

And the relationship between the current and the work bench suction force can be known. That is, as the current increases, the attractiveness of the work bench increases.

When considering the air gap of the magnetic circuit, the calculation using the correction formula is as follows.

을 얻을 수 있고, 환산계수에 따라 1717.55640mT와 같음을 알 수 있다. 상기 수치는 워크벤치 표면의 평균 자기유도이다. 워크벤치 표면에 워크피스를 안착한 후, 워크 피스 표면의 자기유도가 급격히 하락하여 워크피스 재료와 크기가 다양해지고, 워크피스 표면 자기유도를 쉽게 계산할 수 없기 때문에 가우스 곡선을 이용하여 표면을 측정하면 상기 범위는 대략 0.15 내지 140mT이다. 상기 내용을 종합해 보면, 우리는 전력공급 전압을 조절함으로써 전류를 변화시키고 더 나아가 워크피스 표면 자기장 강도를 변화시킴으로써 필요한 흡착력을 얻어 윤활 냉각 성능을 향상시킬 수 있다. δ is the air gap length (㎝), a is the correction factor and (about 3 to 5), assuming a work piece and the work bench air gap δ as _a = 0.15㎝, _and δ = 01.15㎝, the total air gap length and δ = _a + 2δ = 2δ _and 0.06㎝, when calculated as a = 3

And it can be seen that it is equal to 1717.55640mT according to the conversion coefficient. This figure is the mean magnetic induction of the workbench surface. Since the magnetic induction on the surface of the workpiece suddenly drops after the workpiece is seated on the surface of the workbench, the workpiece material and the size thereof are varied and the magnetic induction of the workpiece surface can not be easily calculated. The range is approximately 0.15 to 140 mT. Taking all of the above into consideration, we can improve the lubrication cooling performance by changing the electric current by changing the electric power supply voltage and further changing the magnetic field intensity of the workpiece surface to obtain the necessary attraction force.

When the nozzle injects the three-phase fluid spray onto the grinding zone workpiece surface, the magnetic nanoparticles move along the lines of magnetic force due to the presence of the magnetic field on the surface of the workpiece, and this motion increases the flow resistance of the suspended particles The viscosity of the surface increases and exhibits non-Newtonian flow characteristics. The reason why the phenomenon that the viscosity becomes large as described above is due to the friction between the solid phase particle and the base fluid. In the external magnetic field, the magnetic particles are subjected to magnetic torque and viscous torque. According to the results of the study, when the external magnetic field strength is increased, the viscosity of the magnetic lubricating film is increased, and when the mass fraction of the magnetic nanoparticles is increased, the viscosity of the magnetic lubricating film can be increased.

The increase in the viscosity of the grinding liquid can greatly affect the film forming ability of the grinding liquid, the film forming shape, the oil film thickness and the supporting ability of the oil film. Also, the adsorption ability of nanoparticles on the workpiece surface is increased, and the floating phenomenon of nanoparticles and base oil particles due to compressed air action can be reduced.

In conventional nanoparticle minimum lubrication, we are not sufficiently uniform because the nano-spray can be sprayed and adsorbed on the workpiece surface, and then the compressed gas can blow to form a wavy surface, and even some nanoparticles and base- Is blown into the working surface and forms suspended particles in the surrounding air. This has a bad influence on the formation of the oil film, the environment and the health of the workers. However, since the magnetic nanoparticles have a strong adsorption capability under the action of the magnetic field of the workpiece, the nanoparticles are uniformly distributed and the film is molded, thereby significantly reducing the amount of suspended particles and improving the performance of the oil film.

The distribution of the nanoparticles in the lubricating film formed using the general nano minimum amount lubrication is as shown in FIG. 8, and the oil film formed by the magnetic nanoparticle lubrication under the external magnetic field is as shown in FIG. 9 and 8, the oil film formed by the magnetic nanoparticle lubrication under the external magnetic field is thicker than a conventional nano-minimum amount lubricating oil film and the magnetic nanoparticles are more easily concentrated on the processed surface (higher magnetic nanoparticle content Forming a flux on the workpiece surface). Therefore, the amount of nanoparticles adsorbed on the working surface is significantly higher than that of the conventional nanoparticles of the minimum amount of lubrication. The magnetic nanoparticles are also adsorbed directly on the workpiece surface and make the adsorption considerably robust under the action of an external magnetic field. Thus, when the grinder and the machined surface are in friction, the magnetic nanoparticle lubrication under the external magnetic field produces better robust physically adsorbed film, and because the nanoparticle content of the adsorbed film in the layer is relatively high, the strength and heat dissipation capability Is further improved.

As can be seen from the above, the magnetic nanoparticle minimum magnetic lubrication with external magnetic field not only has all advantages of general nanoparticle minimum lubrication, but also strengthens the thickness and hardness of the oil film and the heat dissipation ability. Also, in the external magnetic field action, since the magnetic grinding fluid is fixed between the grinder and the working surface, there is no serious loss in tangential force action, so that the lubricating oil can be prevented from being lost in the friction system. In addition, it is possible to significantly reduce the suspended particle content in the working environment by effectively controlling the magnetic spray to drift and disperse, which plays a significant role in protecting the health and the environment of the operator.

Since the particle size of the magnetic nanoparticles is very small, there is no magnetic domain wall, the saturation magnetization is high, the magnetism is zero and superparamagnetism is present. An oil film is formed on the surface of the workpiece immediately when there is an external magnetic field when machining. When the workpiece is grinded by the grinder, it is adsorbed on the workbench and does not drift. However, once machining is finished and the workbench is demagnetized, the magnetism disappears immediately, which is very helpful in organizing workpieces and workbenches.

Experimental verification and results of the above embodiment are as follows.

In the experiment, the surface grinding was performed on the 45th steel. The grinding speed was 30m / s, the workpiece feed rate was 0.05m / s, the grinding depth was 30m and the minimum lubrication nozzle flow rate was 2.6ml / min, the compressed air pressure is 6 bar. In the experiment, a diamond grinder is used, and the average particle size of the abrasive grains is 508 탆. The base oil used in the experiment was soybean oil (vegetable oil). 45 steel hardness is HBS 10/3000 wherein each element content is from 0.42 to 0.50% carbon, 0.17 to 0.37% Si, 0.50 to 0.80% Mn, less than or equal to 0.25% Cr, 0.30% Ni Or less, and Cu is less than or equal to 0.25%.

In each of the four lubrication conditions, the minimum amount of lubrication of carbon nanotubes with a mass fraction of 3% is used in Condition 1, the minimum amount of lubrication of MnZnFe ₂ O ₄ nanoparticles with a mass fraction of 3% is used in Condition 2, The surface magnetic induction is 12 mT. In Condition 3, MnZnFe ₂ O ₄ nanoparticles with a mass fraction of 6% are used for the minimum amount of lubrication. The workpiece surface magnetic induction is 12 mT. In condition 4, the MnZnFe ₂ O ₄ nanometer Particle minimum lubrication is used and the workpiece surface magnetic induction is 26mT. The friction coefficient, the diameter of the friction mark and the maximum temperature of the grinding zone were calculated under the four different lubrication conditions.

As shown in Fig. 10, the friction coefficients at the above four conditions were 0.41, 0.35, 0.29, and 0.24, respectively. As shown in Fig. 11, the diameters of the rubbing traces were 1.25 mm, 0.85 mm, 0.71 mm, and 0.54 mm, respectively. As shown in Fig. 12, the maximum grinding zone temperatures were 158 占 폚, 139 占 폚, 128 占 폚 and 117 占 폚, respectively.

Comparing the data of Condition 1 and Condition 2, the minimum amount of magnetic nanoparticle lubrication under the external magnetic field, as described in the above description, was found to be more excellent in friction resistance and heat dissipation ability than general nanoparticle minimum lubrication. This is because the magnetic nanoparticles are more rapidly and firmly adsorbed on the machined surface under magnetic force, and the adsorbed water quantity is also large, so that a relatively thick and robust lubricating film can be formed.

Comparing the data of Condition 2 and Condition 3, it was found that the effect of the minimum amount of magnetic nanoparticle lubrication having a relatively large mass fraction is better when the workpiece surface magnetic induction is the same. This is because relatively relatively large amounts of magnetic nanoparticles adsorb to the working surface more sufficiently to form a relatively thick and rigid oil film. However, if the mass fraction continues to rise above 18%, the quality of the finished surface appears to be rather poor (generally less than 10%). This is because an excessively large number of magnetic nanoparticles have a narrow gap between particles. When the particles are cohered, relatively large granules are formed, which can be ground in the grinding process and damage the working surface.

Comparing the data of Condition 3 and Condition 4, it was found that the oil film formed as the magnetic induction of the workpiece surface becomes stronger and the heat dissipation performance becomes better when the mass fraction of the magnetic nanoparticles is the same. This indicates that when the external magnetic field is strong, the magnetic nanoparticles are more firmly adsorbed on the working surface, and an oil film having excellent performance is formed. However, when the magnetic field strength becomes stronger (generally exceeding 68 mT), magnetic nanoparticles aggregate under magnetic force, which may result in lower workpiece surface quality.

From here,
1: magnetic force workbench 2: workpiece
3: Grinder cover 4: Grinder
5: Magnetic nanofluid transport tube 6: Compressed air transport tube
7: magnetically fixed attracting plate 8: nozzle
9: cover plate 10: suction plate body
11: core 12: coil
13: Antimagnetic layer 14: Air compressor
15: magnetic nanofluid liquid storage tank 16: filter I
17: Filter II 18: Hydraulic pump
19: Gas storage tank 20: Manometer III
21: Pressure regulating valve Ⅱ 22: Pressure regulating valve I
23: throttle valve I 24: throttle valve II
25: Turbine flowmeter I 26: Turbine flowmeter II
27: Pressure gauge Ⅱ 28: Pressure gauge I
29: Relief valve 30: Magnetic nanofluid recovery box
31: N pole pole piece 32: S pole pole piece
33: N pole head plate 34: N pole bar
35: commercial frequency power input terminal 36: ac power transformer
37: DC power supply 38: Operation status indicator
39: demagnetization switch 40: single chip computer management unit
41: Photoelectric connection Silicon control rectifier (SCR) Zero crossing control AC switch unit
42: rectification filter unit 43: automatic overload protection unit
44: areless voltage polarity switching unit
45: DC operation voltage output stage 46: Continuous variable voltage input control unit

Claims (9)

Wherein the workpiece is attached to the top of the magnetic force workbench by a magnetic force, a grinder is installed at the working position of the workpiece, the nozzle is matched with the grinder cover and the workpiece, Wherein the nozzle is connected to the magnetic nanofluid liquid supply device by a magnetic nanofluid transportation pipe and is connected to the air compressor by a compressed air transportation pipe and the magnetic nanofluid and compressed air are mixed in the nozzle The three-phase fluid spray is accelerated, followed by three-phase fluid spraying, the compressed air, the magnetic nanoparticles and the grinding fluid base oil being mixed and sprayed, the three-phase fluid spray entering the grinding section between the workpiece and the grinder, An oil film is formed on the surface of the workpiece;
Wherein the magnetic force workbench is an electromagnetic work bench including a lower attracting plate body and an upper lid plate, wherein a core is disposed in the attracting plate body, a coil is wound around the core body, the coil is connected to a power control circuit, Wherein a plurality of magnetic layers are provided on the cover plate and the cover plate is divided into a plurality of small blocks to form a distribution pattern separated from the N pole and the S pole, Wherein the magnetic nanoparticle jet and the magnetic force workbench coupling form a complete magnetic circuit. delete The method according to claim 1,
Wherein the magnetic layer is made of a non-magnetic material of babbitt metal and has a width c of 2.0 to 4.5 mm. The apparatus for forming an oil film using a magnetic nanoparticle jet and a magnetic force workbench coupling. The method according to claim 1,
And the N-pole blocks and the S pole block total number is an odd number, each of the N-pole blocks, were the width of the S pole blocks are the same, the N-pole single-plate width h _1, the N pole block width h ₃ and the S pole width h ₂ Between

Wherein the magnetic nanoparticle jet and the magnetic force workbench coupling are used. The method according to claim 1,
Wherein the power control circuit comprises a single chip computer management unit, wherein the single chip computer management unit is coupled to an optoelectronic connection silicon controlled rectifier (SCR) zero crossing control AC switch unit, Wherein the crossing control AC switch unit is connected to a rectification filter unit, the rectification filter unit is connected to an overload automatic prevention unit, the overload automatic prevention unit is connected to an arcless voltage polarity switching control unit, The polarity switching control unit outputs an operating voltage to the coil, the optoelectronic connection SCR zero crossing control AC switch unit is connected to an AC power transformer, the AC power transformer is connected to a commercial frequency power circuit input, The unit is also connected to a continuous variable voltage input control unit, Wherein the continuously variable voltage input control unit is connected to the optoelectronic connection SCR zero crossing control AC switch unit and the single chip computer management unit is connected to the arcless voltage polarity switching unit to become a demagnetization circuit An apparatus for forming an oil film using a magnetic nanoparticle jet and a magnetic workbench coupling. The method according to claim 1,
Wherein the nozzles and the workpiece distance d are between 10 and 25 cm and the narrowing angle a of the nozzles and the workpiece is between 15 and 45. The oil film forming apparatus of claim 1, The magnetic force workbench comprises the steps of: 1) adsorbing and fixing a workpiece on a surface, and placing the grinder at a processing position on the workpiece;
Spraying a three-phase fluid spray formed by the magnetic nanofluid and compressed air to the grinding zone between the workpiece and the grinder when the grinding is started;
The magnetic field of the workpiece surface causes the magnetic nanoparticles to move along a line of magnetic force, the magnetic nanoparticles enhance the adsorption capability of the workpiece surface, and when the friction between the grinder and the work surface occurs, Step 3 being formed;
And a step (4) of waiting for the completion of the machining to proceed with the device of the magnetic force workbench. The process for forming a film of an oil film forming apparatus using a magnetic nanoparticle jet and a magnetic workbench coupling. 8. The method of claim 7,
Wherein the injection flow rate of the nozzle is 2.5 to 5.5 ml / min, and the pressure of the compressed air is 4.0 to 10 bar. The process for forming a film of an oil film forming apparatus using a magnetic nanoparticle jet and a magnetic work bench coupling. 8. The method of claim 7,
Wherein the nano particle size of the magnetic nanofluids is less than or equal to 100 nm and the content of the nanoparticles is in the range of 1% to 30 vol%. The magnetic nanoparticle jet and the oil film formation using the magnetic force work bench coupling Film forming process of the device.

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