CN114279900A - Testing device and method for real wettability of functional surface of cutter in thermomagnetic environment - Google Patents

Abstract

The invention discloses a device and a method for testing the real wettability of a functional surface of a cutter in a thermomagnetic environment. The testing device comprises a base, and a force-heat-magnetic loading module, a cutter clamping module, a double-liquid-drop automatic dropping module, an analysis module and a CCD recording and analyzing module which are arranged on the base. A frame is arranged on the base; the tool holding module is mounted on top of the frame. The force-heat-magnetism loading module is arranged between the two clamping parts of the tool clamping module and used for applying pressure from bottom to top to a sample to be measured clamped on the tool clamping module, heating the sample to be measured and applying a magnetic field. The invention can carry out stress loading, temperature loading and magnetic force loading on the tested sample, provides a corresponding detection method under various loading conditions, and realizes the detection of various performances of the tested sample.

Description

Testing device and method for real wettability of functional surface of cutter in thermomagnetic environment

Technical Field

The invention relates to the technical field of surface wettability testing, in particular to a device and a method for testing the real wettability of a functional surface of a cutter.

Background

The cutting machining is widely applied to the forming manufacturing machining of key/base parts of high-end intelligent equipment. In order to effectively improve the friction condition between the cutter and the tool bits and reduce the abrasion of the cutter teeth, a surface microstructure with a fine scale is usually formed on the surface of the cutter teeth, so as to adjust and control the lubricating and wetting characteristics of the surface of the cutter. However, in the actual cutting process, the cutter teeth are loaded and deformed, so that the wetting performance of the arranged surface microstructure is unpredictably changed, and the improvement of the cutting quality is not facilitated. Therefore, how to effectively test the wetting performance of the functional surface of the cutter in a loaded state and further optimize the microstructure of the functional surface is very important.

At present, there are some mature testing methods and devices for measuring surface wettability under different requirements in different fields. For example, the invention patent with application number 200610085447.9 discloses an on-site electrochemical contact angle measurement method and device based on a micro-nano interface, wherein a contact angle measurement instrument is used in combination with other measurement or generation devices, and the contact angle of a substrate to be measured under the condition of an external electric field, a magnetic field or illumination can be dynamically measured under the condition of quantitative external application or measurement of external physical signals. For example, the invention patent with the application patent number of 201710823523.X discloses a contact angle measuring method and a device with a novel liquid distribution method, wherein the device has a bidirectional liquid adding function, and can also be used for full-automatic and long-time measurement of liquid surface/interface tension (including dynamic surface tension) by performing dynamic forward/backward contact angle measurement in a liquid drop volume increasing/reducing process and accurately controlling a hanging drop volume, measurement of liquid surface viscoelastic modulus and other applications. For example, the invention patent with the application patent number of 201910696093.9 discloses a measuring device and a method for measuring the contact angle between liquid and solid in a high-temperature environment, wherein an adjusting base, a heating plate, a to-be-measured molten sample and a to-be-measured substrate are directly arranged in a vacuum box. For example, the invention patent with application patent number 2021102707.X discloses a device and a method for measuring a contact angle in a multi-medium environment under high temperature and high pressure, aiming at the defects of the existing device, the device which is simple and convenient to operate, high in measurement precision, good in sealing performance, capable of rapidly reaching the temperature and pressure required by an experiment and strong in temperature and pressure controllability is designed, and the device is combined to provide a set of method for measuring the contact angle in the multi-medium environment under high temperature and high pressure.

However, the testing method and the testing device cannot detect the real surface wettability of the functional surface of the cutter tooth under the loaded condition.

Disclosure of Invention

In order to solve the problems in the prior art, the invention mainly aims to provide a method and a device for detecting and analyzing the real wettability of the functional surface of the cutter by simulating a force-heat complex environment in cutting processing, wherein the device can simulate the working conditions of cutting heat (less than 300 ℃) and cutting force (less than 2000N) and detect and analyze the wettability of the functional surface of the cutter under different working conditions; meanwhile, force-heat-magnetism and different nano-fluids can be applied to detect and analyze the regulation and control effect of the microstructure on the wettability of the surface of the cutter; the device can also be used for realizing the accelerated test of the lubricating film on the surface of the cutter from generation to failure.

The invention relates to a testing device for testing the real wettability of a functional surface of a cutter in a thermomagnetic environment, which comprises a base, and a force-heat-magnetism loading module, a cutter clamping module, a double-liquid-drop automatic dropping module, an analysis module and a CCD recording and analysis module which are arranged on the base. A frame is arranged on the base; the tool holding module is mounted on top of the frame. The force-heat-magnetism loading module is arranged between the two clamping parts of the cutter clamping module and used for applying pressure from bottom to top to a sample to be measured clamped on the cutter clamping module, heating the sample to be measured and applying a magnetic field.

The drip module bracket is arranged at the top of the frame; the backlight lamp is arranged at the side part of the dripping module bracket through the backlight bracket. The automatic double-liquid-drop dropping module is arranged at the top of the dropping module support and is arranged downwards. The double-droplet automatic dropping module is positioned right above the force-heat-magnetic loading module. The backlight and the CCD recording and analyzing module are respectively positioned on the opposite sides of the force-heat-magnetism loading module and are used for recording spreading images of the cutting fluid dripped on the tested sample and analyzing the contact angle change condition of the cutting fluid on the tested sample under different loading conditions.

The force-heat-magnetism loading module comprises a loading plate and a jacking assembly. The loading plate is installed on the jacking assembly. The jacking assembly is used for driving the loading plate to perform lifting movement. The loading plate can be adjusted in position on the jacking assembly along the transverse direction. The loading plate comprises a plate body, an electromagnet, a heat source and a heat insulation plate. The middle position of the top of the plate body is provided with a force applying strip. A pressure sensor is arranged between the force applying strip and the plate body. A magnetizing cavity and a heating cavity are arranged in the plate body. The heating chamber is positioned right below the stressing strip. A heat insulation plate is arranged between the magnetizing cavity and the heating cavity. The heating chamber is positioned on one side of the heat insulation plate close to the stress application part. An electromagnet is arranged in the magnetizing cavity. A heat source is installed in the heating chamber.

Preferably, the jacking assembly comprises a servo motor, a speed reducer, a lead screw, a lifting platform and a guide rail. The guide rail that sets up vertically is fixed on the frame. The lifting platform and the guide rail form a sliding pair. The vertically arranged threaded spindle is supported on the frame. The screw rod and the nut on the lifting platform form a screw pair. And an output shaft of the servo motor is fixed with an input port of the speed reducer. The output shaft of the speed reducer is fixed with the end part of the screw rod.

Preferably, the loading plate is connected to the top of the lifting table in a sliding mode along the horizontal direction, and the transverse position of the loading plate is adjusted through the precision micrometer sliding table.

Preferably, the stress application part at the top of the stress application strip is in a circular arc shape.

Preferably, the double-droplet automatic dripping module comprises a dripping lifting sliding table and two sample injectors. Two sample injectors are arranged on a sliding plate of the liquid dropping lifting sliding table in parallel, and can add cutting liquid to two sides above the force application strip. The piston rod of the sample injector is driven by an electric sliding table.

Preferably, the CCD recording and analyzing module comprises a CCD camera and a three-axis adjusting component. The CCD camera adjusts the height and the horizontal position of the CCD camera through the three-axis adjusting assembly. The triaxial adjusting assembly comprises a scissor fork lifting mechanism for adjusting the height and a micrometer sliding table for horizontally adjusting the two directions.

A test method for the real wettability of the functional surface of a cutter in a thermomagnetic environment uses the test device; the test method comprises a test method under the condition of force loading-unloading, and comprises the following specific steps:

step one, the jacking assembly drives the loading plate to be lowered to a lower limit position, the miniature sample injector is filled with cutting fluid and then placed on the double-liquid-drop automatic dripping module, the sample to be measured is fixed on the clamping module, the backlight plate is opened, and the height of the CCD lens is adjusted, so that the upper plane of the sample to be measured appears in the observation visual field. At this time, the loading force F of the loading plate to the sample to be measured₁And simultaneously, adhering a strain gauge on the upper surface of the sample to be measured, wherein the strain gauge is 0.

And step two, the jacking assembly drives the loading plate to rise, so that the stressing strip on the loading plate is in contact with the lower surface of the sample to be tested, and loading force is generated.

Step three, synchronously dripping 2 microliter drops by two sample injectors of the double-drop automatic dripping module, observing and recording contact angles of the two drops on the surface of the sample to be measured by a CCD camera within 5s after dripping, and obtaining an apparent contact angle theta under the loading after calculating the average value_s，1. Meanwhile, the stress value sigma of the stressed area of the tested sample is obtained through the output signal conversion of the strain gauge₁。

Step four, the jacking assembly drives the loading plate to rise, and the loading force reaches F₂100N; at this point, step three is repeated to obtain the apparent contact angle theta under the loading_s，2(ii) a Meanwhile, the stress value sigma of the stressed area of the tested sample is obtained through the output signal conversion of the strain gauge₂。

Step five, adjusting the loading force of the jacking assembly to F₃＝500N，F₄＝1000N，F₅Stopping at 2000N, and repeatingRepeating the third step to obtain the apparent contact angle theta under each loading_s，3，θ_s，4And theta_s，5And stress value σ of the force-receiving area₃，σ₄And σ₅。

Sixthly, adopting a least square method polynomial fitting method according to (sigma)_k,θ_k) K is 1,2,. 5; fitting contact angle under force loading condition as approximate function relation theta-f₁(σ)＝a₁σⁿ+……+a_n(ii) a Theta is the contact angle of the measured cutting fluid; sigma is the stress value of the tested sample in the stressed area; a is₁～a_nIs a plurality of fitting coefficients.

Step seven, the jacking assembly drives the loading plate to be lowered, and the loading force is adjusted to F₆＝1000N，F₇＝500N，F₈100N and F₉Stopping the operation when the contact angle is 1N, repeating the step three, and obtaining the apparent contact angle theta under the unloading condition₆，θ₇，θ₈And theta₉。

Step eight, similarly adopting a least square fitting method to fit the contact angle under the condition of force unloading into an approximate function relationship, wherein theta is f₂(σ)＝b₁σⁿ+……+b_n；b₁～b_nAre fitting coefficients.

Step nine, transversely adjusting the position of the loading plate to enable one sample injector to drip liquid drops at a specific distance L from the force application point, repeating the step two to the step eight to obtain a contact angle fitting approximate function relation under the condition of force loading and unloading introducing the position relation, wherein theta is f₃(σ,L)＝c₁σⁿ+……+c_nLⁿAnd θ ═ f₄(σ,L)＝d₁σⁿ+……+d_nLⁿ。

And step ten, predicting the real wettability change condition of the cutting fluid to the cutter in the cutting loading-unloading process of the cutter prepared by the tested sample according to the fitting function relation. The method for predicting the actual wettability change is to calculate the cutting force value at the edge according to the processing parameters and the geometrical parameters of the tool and then to determine the actual wettability change by means of the cutting force valueLimiting element simulation is carried out to calculate a stress cloud picture of the surface of the cutter, and the stress value is substituted into a function f₁Or f₃In the method, the change of the wetting angle of the cutting fluid at the blade edge and at different distances from the blade edge is obtained.

Preferably, the test method also comprises a test method under the condition of force-heat loading, and the specific steps are as follows:

step one, the jacking assembly drives the loading plate to rise, so that the stressing strip on the loading plate is in contact with the lower surface of the sample to be measured. At this time, the loading force reaches F₁1N. Starting a heating module to a temperature T₁Keeping the temperature at 50 ℃ for 5min, starting two sample injectors, synchronously dropping 2 microliter drops by the sample injectors, observing and recording the contact angles of the two drops on the surface of the sample piece within 1s after dropping, and obtaining the apparent contact angle under the loading after averaging

And detecting the stress value sigma (T) to which the sample is subjected at the moment₁)。

Step two, controlling the heating module to raise the temperature to T₂＝100℃、T₃150 ℃ and T₄After 200 ℃, repeat step one and record the apparent contact angle at each heat loading condition

And

and detecting the stress value sigma (T) corresponding to each apparent contact angle₂)、σ(T₃)、σ(T₄). The stress value as a function of temperature, σ (T), is fitted.

The contact angle fit under heat loading conditions was constructed as an approximate functional relationship as follows:

wherein the content of the first and second substances,

the contact angle of the measured cutting fluid along with the temperature change; sigma (T) is a stress value borne by a stressed area of the tested sample at the temperature of T under the preset loading force; and x and K are fitting coefficients.

Step three, transversely adjusting the position of the loading plate for multiple times, adjusting the distance L between the dropping position of the liquid drop and the heat source, and repeating the step one and the step two to obtain the apparent contact angle at each position

And fitting to a functional form

α₁And beta₁Are two fitting parameters.

Step four, controlling the heating module to reduce the temperature to T₅＝150℃、T₆100 ℃ and T₇Repeating steps one and three at 50 deg.C, fitting the apparent contact angle under the thermal unloading condition to a functional form

α₂And beta₂Are two fitting parameters.

Step five, adjusting the loading force of the jacking assembly to be F₂＝100N，F₃＝500N，F₄＝1000N，F₅Repeating steps one to four when the number is 2000N, and fitting the apparent contact angle under the loading and unloading conditions of force-heat into a functional form

And

and step six, predicting the real wettability of the prepared cutter surface microstructure in the cutting force-heat coupling loading-unloading process according to the fitting function relation.

Preferably, the test method also comprises a method for analyzing and evaluating the regulation effect of the microstructure on the wettability of the surface of the cutter, and the method comprises the following specific steps:

step one, clamping a tested sample provided with a microstructure identical to that of the cutter on a cutter clamping module.

Step two, starting the single-side sample injector to drop 2 microliters of liquid drops to the edge position of the microstructure, observing, and recording the spreading length W of the liquid drops₁(t) and liquid film thickness H₁(t) and calculating the two-dimensional spreading speed

Wherein t is time.

Thirdly, adjusting the pressure of the loading plate on the sample to be measured for multiple times, so that the pressure on the sample to be measured is gradually increased and is adjusted for multiple times to reach a preset limit pressure value; the force loading point is positioned at the edge of the microstructure of the tested sample; after the pressure of the loading plate on the sample piece to be measured is adjusted each time, the step two is executed again, and the spreading length W of the liquid drop under the load is observed and obtained_k(t) liquid film thickness H_k(t) and calculating the two-dimensional spreading speed

k is the ordinal number of pressure adjustment, and takes a value of 2, 3.

Step four, spreading all the two adjacent two-dimensional spreading speeds V_k(t) comparing every two to calculate the spreading speed judgment coefficient mu when the pressure applied to the sample to be measured increases_kThe following were used:

mu.s of_k>0, under the corresponding loading condition, the spreading speed of the liquid drop on the current surface of the tested sample is greater than the spreading speed of the liquid drop before the pressure load is increased for the last time, and the micro-structure is judged not to reach the pole with improved wettabilityAnd (4) limiting.

Mu.s of_kWhen the spreading speed of the liquid drop on the current surface of the tested sample is less than or equal to the spreading speed of the liquid drop before the increase of the pressure load is recently exceeded under the corresponding loaded condition, judging that the microstructure reaches or exceeds the limit of wettability improvement; at this time, the pressure on the sample to be tested is not further increased, and the test is ended.

Taking the spreading speed to determine the coefficient mu_kAnd when the condition of being less than or equal to 0 occurs for the first time, the stress value of the loading position of the tested sample is used as the critical stress for regulating and controlling the wetting and spreading speed of the surface of the microstructure, and the step seven is directly carried out.

If the pressure of the loading plate on the tested sample reaches a preset limit pressure value, the spreading speed judgment coefficient mu_kIf still greater than 0, go to step five.

Step five, enabling the thicknesses H of all adjacent two liquid films_k(t) comparing every two to calculate the judgment coefficient eta of the thickness of the liquid spreading film when the pressure on the sample to be measured increases every time_kThe following were used:

taking the thickness determination coefficient eta of the liquid spreading film in the process that the pressure value of the tested sample is increased from small to small_kAnd when the condition of being less than or equal to 0 occurs for the first time, the stress value of the loading position of the measured sample is used as the critical stress for regulating and controlling the surface liquid storage property of the microstructure, and the process directly enters the step seven.

If the pressure of the loading plate on the tested sample reaches a preset limit pressure value, the determination coefficient eta of the thickness of the liquid spreading film_kIf still greater than 0, go to step six.

Step six, after increasing the limit pressure value set in the step three, repeatedly executing the step four and the step five until the mu appears_kLess than or equal to 0 or eta_kAnd if the temperature is less than or equal to 0, entering the step seven.

Step seven, obtaining the spreading speed V of the liquid drop under the standing condition through testing₀And the thickness H of the spreading liquid film₀And calculating the spreading speed normalization index lambda under different loading conditions_xNormalized index lambda of liquid film thickness_yThe following were used:

wherein, V₀The spreading speed under the standing condition is taken as a reference value of the spreading speed; h₀The thickness of the liquid film under the standing condition is taken as a reference value of the thickness of the spreading liquid film; when V is_k(t) is much larger than the reference value, λ_x-1; when V is_kλ when (t) is equal to the reference value _x0; when V is_k(t) is much greater than the reference value, λ_x＝1；λ_yThe same can be obtained.

Normalization of the index lambda with the spreading speed under the respective different loading conditions_xAs abscissa, normalized index lambda of liquid film thickness_yAnd constructing a distribution cloud picture as a longitudinal coordinate.

And step eight, respectively corresponding each discrete point in the distribution cloud chart to the wettability and the liquid storage performance of the tested sample under different stress conditions. When the discrete point is positioned at the third quadrant, the microstructure is shown to completely inhibit the wettability of the surface of the cutter under the corresponding stress condition; when the discrete point is positioned at the second quadrant, the microstructure inhibits the spreading speed of the liquid drop under the corresponding stress condition, and the liquid storage property is improved; when the discrete point is positioned in the fourth quadrant, the microstructure is shown to improve the spreading speed of the liquid drop under the corresponding stress condition, and the liquid storage property is inhibited; when the values are in the first quadrant, the microstructure is shown to increase both the droplet spreading speed and the liquid retention.

Preferably, the test method also comprises a tool surface lubricating film acceleration test method, and the specific steps are as follows:

step one, filling magnetic nanometer fluid into a sample injector.

Step two, starting the two sample injectors and the magnetism adding module to enable the liquid drops to synchronously drip 2 microlitre of liquid drops, and adjusting the magnetic field intensity to B within 5s after dripping₁And recording the spreading of the magnetic nanofluid dropletLength W, spreading speed V and liquid film thickness H at the final spreading position.

Step three, adjusting the magnetic field intensity to be B in sequence₂，B₃，B₄，……，B_nAnd repeating the second step to obtain the spreading parameters of the magnetic nano fluid under various magnetic field strengths.

And step four, replacing the pressure load change with the magnetic field strength load change by adopting a method recorded in the method of regulating and controlling the tool surface wettability by the microstructure and evaluating the regulating and controlling effect of the coupling effect of the microstructure and the magnetic field on the wettability of the magnetic nano fluid.

Preferably, the test method also comprises a tool surface lubricating film acceleration test method, and the specific steps are as follows:

step one, clamping a sample to be tested provided with a microstructure on a cutter clamping module.

Step two, keeping the room temperature T_s1Starting two sample injectors at 20 ℃ to synchronously drip 2 microlitre of liquid drops on the edge of the microtexture, recording transient images and recording t₁0s, measuring the height h of 5 groups of liquid films by taking 5 mu m as step length from the highest point of the liquid films of the two liquid drops to two sides₁,h₂,h₃,……,h₂₀Obtaining effective value H of the thickness of the whole liquid film at room temperature_rms。

Step three, recording the liquid film spreading image every 3S through a CCD, and recording the time t₂,t₃,t₄,……,t_nAnd calculating the effective value H of the whole liquid film thickness at the time t by using the method of the step two_rms1(t) fitting the time variation along with the thickness of the whole liquid film under the normal temperature condition into an approximate functional relation H by adopting a least square fitting method_rms1(t)＝p₁tⁿ+……+p_nAnd t is considered to be HT₁， H_rms1(t)<H_pIn the meantime, it is considered that a liquid film having a thickness of less than this cannot completely coverA contact surface.

Step four, removing the liquid film on the sample to be tested; dropping double liquid drops at the edge of the microtexture again, repeating the third step, and recording and fitting the time function H of the effective value of the liquid film thickness_rms2(t) and obtaining a liquid film failure value H_pTime of flight HT₂。

Step five, repeating the step four, and obtaining the liquid film failure time HT at different temperatures_kAccording to an Arrhenius acceleration model, the fitting relation between the liquid film service life HT and the temperature T is obtained

ln HT＝A+B/T

Wherein A and B are fitting coefficients.

Step six, based on the life model fitted in the step five, calculating an acceleration coefficient of T_kTo the cutting temperature, T₀At room temperature.

And step six, comparing the acceleration coefficients under different microstructures, wherein the smaller the acceleration coefficient is, the better the thermal stability of the liquid film is.

The invention has the beneficial effects that:

the invention can carry out stress loading, temperature loading and magnetic force loading on the tested sample, provides a corresponding detection method under various loading conditions, and realizes the detection of various performances of the tested sample.

Drawings

Fig. 1 is a perspective view of the overall structure of the present invention.

Fig. 2 is a schematic structural diagram of a "force-heat-magnetic" loading module in the present invention.

Fig. 3 is a schematic view of a loading plate according to the present invention.

Fig. 4 is a schematic structural diagram of a CCD recording and analyzing module according to the present invention.

Detailed Description

As shown in figure 1, the testing device for testing the real wettability of the functional surface of the cutter in the 'force-heat-magnetism' environment comprises a base 10, and a 'force-heat-magnetism' loading module, a cutter clamping module 7, a double-liquid-drop automatic dropping module, an analysis module and a CCD recording and analysis module which are arranged on the base 10. The base 10 is provided with a frame 1; the tool holding module is mounted on top of the frame 1. The force-heat-magnetism loading module is arranged between the two clamping parts of the tool clamping module and used for applying pressure from bottom to top to a sample to be measured clamped on the tool clamping module, heating the sample to be measured and applying a magnetic field.

The drip module support 2 is mounted on the top of the frame 1; the backlight 3 is mounted on the side of the drip module holder 2 via a backlight holder 4. The automatic double-droplet dripping module is arranged at the top of the dripping module bracket 2 and is arranged downwards. The double-liquid-drop automatic dropping module is positioned right above the force-heat-magnetic loading module. The backlight 3 and the CCD recording and analyzing module are respectively positioned at two sides of the force-heat-magnetism loading module and are used for recording spreading images of the cutting fluid dripped on the tested sample and analyzing the contact angle change condition of the cutting fluid on the tested sample under different loading conditions.

As shown in fig. 2, the "force-thermal-magnetic" loading module 800 includes a load plate and a jacking assembly. The jacking assembly comprises a servo motor 805, a reducer 809, a lead screw, a lifting platform 806 and a guide rail 808. A vertically arranged guide rail 808 is fixed to the frame 1. The lift platform 806 and the guide rail 808 form a sliding pair. A vertically arranged spindle is supported on the frame 1. The screw rod and the nut on the lifting platform 806 form a screw pair. The output shaft of the servo motor 805 is fixed to the input port of the reducer 809. The output shaft of the reducer 809 is connected with the bottom end of the screw rod through a coupling.

As shown in fig. 3, the loading plate is slidably attached to the top of the lifting table 806 in the horizontal direction, and the lateral position is adjusted by a precision micrometer sliding table 807. The loading plate comprises a plate body, an electromagnet 801, a heat source 802 and a heat insulation plate 803. The middle position of the top of the plate body is provided with a stress application strip. A pressure sensor is arranged between the stress application strip and the plate body. The stress application part at the top of the stress application strip is arc-shaped. The force applying strip is used for extruding the tested sample, so that the tested sample is bent and deformed. A magnetizing cavity and a heating cavity are arranged in the plate body. The heating chamber is positioned right below the force application strip. An insulating plate 803 is disposed between the one or more magnetizing chambers and the heating chamber. The heating chamber is located on the side of the heat shield 803 near the force application location. An electromagnet 801 is installed in the magnetizing chamber. A heat source 802 is mounted within the heating chamber. The heat source 802 is an electric heating element in a strip shape and is arranged in the heating chamber.

The tested sample needs to be uniformly manufactured into a rectangular plate with the length of 120mm, the width of 30mm and the thickness of 10 mm. The tool clamping module 7 adopts a quick clamping mechanism and is used for fixing a sample to be measured.

The double-liquid-drop automatic dripping module 5 comprises a liquid dropping lifting sliding table and two sample injectors. Two sample injectors are arranged on a sliding plate of the dropping liquid lifting sliding table side by side and can add cutting liquid to two sides above the stress application strip. The piston rod of the sample injector is driven by the electric sliding table.

The CCD recording and analyzing module comprises a CCD camera and a three-axis adjusting component. The CCD camera adjusts the height and the horizontal position of the CCD camera through the three-axis adjusting assembly. The three-axis adjusting assembly comprises a shear fork lifting mechanism used for adjusting the height and a thousand-minute ruler sliding table used for the horizontal two directions.

The testing device for testing the real wettability of the functional surface of the cutter in the force-heat-magnetic environment comprises the following specific steps: method for testing under 'force loading-unloading' condition, method for testing under 'force-heat loading' condition, method for analyzing and evaluating regulating and controlling effect of microstructure on wettability of surface of cutter and method for testing acceleration of lubricating film on surface of cutter

(1) The testing method under the condition of 'force loading-unloading' is used for detecting and analyzing the real wettability of the functional surface of the cutter under the condition of 'force loading-unloading', and comprises the following specific steps:

step one, the jacking assembly drives the loading plate to be lowered to a lower limit position, the miniature sample injector is filled with cutting fluid and then placed on the double-liquid-drop automatic dripping module, the sample to be measured is fixed on the clamping module, the backlight plate is opened, and the height of the CCD lens is adjusted, so that the upper plane of the sample to be measured appears in the observation visual field. At this time, the loading force F of the loading plate to the sample to be measured₁And (5) simultaneously pasting a strain gauge on the upper surface of the sample to be detected, and constructing a bridge type detection circuit.

And step two, the jacking assembly drives the loading plate to rise, so that the stressing strip on the loading plate is in contact with the lower surface of the sample to be measured. At this time, the loading force reaches F₁1N. At this time, the position of the load plate is recorded and set as a base point for lifting.

Step three, synchronously dripping 2 microliter liquid drops by two sample injectors of the double-liquid-drop automatic dripping module, observing and recording contact angles of the two liquid drops on the surface of the tested sample by a CCD camera within 5s after dripping (each liquid drop is measured 10 times by adopting a five-point fitting method), and obtaining an apparent contact angle theta under the loading after calculating the average value_s，1。

Wherein, theta_iThe contact angle measured for the ith time of the first droplet; theta'_jThe contact angle measured for the jth drop of the second drop.

Step four, the jacking assembly drives the loading plate to rise, and the loading force reaches F₂100N; at this point, step three is repeated to obtain the apparent contact angle theta under the loading_s，2(ii) a Meanwhile, the stress value sigma of the stressed area of the tested sample is obtained through the output signal conversion of the strain gauge₂。

Step five, adjusting the loading force of the jacking assembly to F₃＝500N，F₄＝1000N，F₅Stopping at 2000N and repeating step three to obtain apparent contact angle theta_s，3，θ_s，4And theta_s，5And stress value σ of the force-receiving area₃，σ₄And σ₅。

Sixthly, adopting a least square method polynomial fitting method according to (sigma)_k,θ_k) K is 1,2,. 5; fitting contact angle under force loading condition as approximate function relation theta-f₁(σ)＝a₁σⁿ+……+a_n(ii) a Theta is measured cutting fluidContact angle of (a); sigma is the stress value of the tested sample in the stressed area; a is₁～a_nIs a plurality of fitting coefficients.

Step seven, the jacking assembly drives the loading plate to be lowered, and the loading force is adjusted to F₆＝1000N，F₇＝500N，F₈100N and F₉Stopping the operation when the contact angle is 1N, repeating the step three, and obtaining the apparent contact angle theta under the unloading condition₆，θ₇，θ₈And theta₉。

Step eight, similarly adopting a least square fitting method to fit the contact angle under the condition of force unloading into an approximate function relationship, wherein theta is f₂(σ)＝b₁σⁿ+……+b_n；b₁～b_nAre fitting coefficients. If only the wetting characteristic at the loading point is concerned, ending the experiment and entering the step ten; if the influence of the gradient effect caused by the force loading-unloading on the wetting characteristic needs to be concerned, the step nine is continued.

Step nine, transversely adjusting the position of the loading plate through a sliding table 807 of a precision micrometer to enable one of the sample injectors to drip liquid drops at a position which is a specific distance L away from a force application point, repeating the step two to the step eight to obtain a contact angle fitting approximate function relationship under the condition of force loading and unloading introducing the position relationship, wherein theta is f₃(σ,L)＝c₁σⁿ+……+c_nLⁿAnd θ ═ f₄(σ,L)＝d₁σⁿ+……+d_nLⁿ。

Step ten, according to the fitting function relationship, the real wettability change condition of the cutting fluid to the cutter in the cutting loading-unloading process of the prepared cutter surface microstructure can be predicted, and simultaneously, the geometric parameters of the microstructure can be optimized according to the prediction result. The method for predicting the real wettability change comprises the steps of calculating the cutting force value at the position of a blade according to the processing parameters and the geometric parameters of the cutter, calculating a stress cloud chart of the surface of the cutter through finite element simulation, and substituting the stress value into a function f₁Or f₃In the method, the change condition of the wetting angle of the cutting fluid at the blade and at a certain distance from the blade can be obtained; preferably microThe structural geometry is based on the fact that the closer to the cutting edge, the smaller the wetting angle, i.e. the microstructure with higher solid-liquid affinity, is more suitable for the cutting conditions, so that the function f of the microstructure with different geometrical parameters is fitted₃Comparing to obtain a more optimal geometric parameter corresponding to the microstructure with the wetting angles at different positions showing obvious gradient characteristics; while also being able to compare the function f₂Or f₄The function fitted by the microstructures with different geometric parameters has a faster hysteresis characteristic, and the corresponding geometric parameters are better.

If the influence of the cutting temperature is neglected, the process can meet the requirement of detecting and analyzing the real wettability of the surface of the cutter, and the following steps are required by further considering the force-heat coupling effect.

(2) The method for detecting and analyzing the real wettability of the functional surface of the cutter under the condition of force-heat loading comprises the following specific steps:

step one, the jacking assembly drives the loading plate to rise, so that the stressing strip on the loading plate is in contact with the lower surface of the sample to be measured. At this time, the loading force reaches F₁1N. Starting a heating module to a temperature T₁Keeping the temperature at 50 ℃ for 5min, starting two sample injectors, synchronously dropping 2 microliter drops by the sample injectors, observing and recording the contact angles of the two drops on the surface of the sample piece within 1s after dropping through a CCD (each drop is measured 10 times by adopting a five-point fitting method), and obtaining the apparent contact angle under the loading after averaging

And detecting the stress value sigma (T) to which the sample is subjected at the moment₁)。

Step two, controlling the heating module to raise the temperature to T₂＝100℃、T₃150 ℃ and T₄After 200 ℃, repeat step one and record the apparent contact angle at each heat loading condition

And

and detecting the stress value sigma (T) corresponding to each apparent contact angle₂)、σ(T₃)、σ(T₄). The stress value as a function of temperature, σ (T), is fitted.

The construction fits the contact angle under heat loading conditions as an approximate functional relationship as follows:

wherein the content of the first and second substances,

the contact angle of the measured cutting fluid along with the temperature change; sigma (T) is a stress value borne by a stressed area of the tested sample at the temperature of T under the preset loading force; and x and K are fitting coefficients.

Step three, transversely adjusting the position of the loading plate for multiple times through a precision micrometer sliding table 807, adjusting the distance L between the dropping position of the liquid drop and a heat source, and repeating the step one and the step two to obtain apparent contact angles at all positions

And fitting to a functional form

α₁And beta₁Are two fitting parameters.

Step four, controlling the heating module to reduce the temperature to T₅＝150℃、T₆100 ℃ and T₇Repeating steps one and three at 50 deg.C, fitting the apparent contact angle under the thermal unloading condition to a functional form

α₂And beta₂Are two fitting parameters.

Step five, adjusting the loading force of the jacking assembly to be F₂＝100N，F₃＝500N，F₄＝1000N，F₅Repeating steps one to four, loading and unloading the force-heat conditions when the number is 2000NApparent contact angle of

And

and step six, according to the fitting function relationship, the real wettability of the prepared tool surface microstructure in the cutting force-heat coupling loading-unloading process can be predicted, and meanwhile, the geometric parameters of the microstructure can be optimized according to the prediction result.

The prediction and evaluation method is consistent with the method, and mainly substitutes the stress value and the temperature value which are calculated by simulation into a function

Obtaining the change condition of the wetting angle of the cutting fluid at the position of the lower blade and at a certain distance from the blade by force-heat coupling; by fitting functions of microstructure of different geometric parameters

The geometric parameters corresponding to the microstructures with obvious gradient characteristics of wetting angle distribution obtained by comparison are better; at the same time, the function can be compared

And

under the same stress value, temperature value and position, if the hysteresis characteristic is more rapid, the corresponding geometric parameters are more optimal.

If the spreading and wetting of the cutting fluid in the cutting process is simplified into a static process, the process can meet the requirements of detection and analysis of the real wetting of the surface of the cutter, and the following steps are required in further consideration of the dynamic spreading characteristic of the cutting fluid.

(3) The method for analyzing and evaluating the regulation and control effect of the microstructure on the surface wettability of the cutter comprises the following specific steps:

and step one, returning the testing device to the initial setting, and clamping the tested sample provided with the microstructure same as that of the cutter.

Step two, starting the single-side sample injector to drop 2 microliters of liquid drops to the edge position of the microstructure, observing, and recording the spreading length W of the liquid drops₁(t) and liquid film thickness H₁(t) and calculating the two-dimensional spreading speed

Wherein t is time.

Thirdly, adjusting the pressure of the loading plate on the sample to be measured for multiple times, so that the pressure on the sample to be measured is gradually increased and is adjusted for multiple times to reach a preset limit pressure value; the force loading point is positioned at the edge of the microstructure of the tested sample; after the pressure of the loading plate on the sample piece to be measured is adjusted each time, the step two is executed again, and the spreading length W of the liquid drop under the load is observed and obtained_k(t) liquid film thickness H_k(t) and calculating the two-dimensional spreading speed

k is the ordinal number of pressure adjustment, and takes a value of 2, 3.

Step four, spreading all the two adjacent two-dimensional spreading speeds V_k(t) comparing every two to calculate the spreading speed judgment coefficient mu when the pressure applied to the sample to be measured increases_kThe following were used:

mu.s of_k>When the pressure of the liquid drop is 0, under the corresponding loaded condition, the spreading speed of the liquid drop on the current surface of the tested sample is greater than the spreading speed of the liquid drop before the pressure load is increased for the last time, so that the micro structure on the tested sample can continuously improve the wettability of the surface of the cutter along with the increase of the load under the stress corresponding to the current pressure, represent the micro structure and realize the effect of improving the wettability of the surface of the cutter along with the increase of the loadThe limit of wettability improvement was not reached.

Mu.s of_kWhen the pressure of the liquid drop on the current surface of the tested sample is less than or equal to 0, the spreading speed of the liquid drop on the current surface of the tested sample is less than or equal to the spreading speed of the liquid drop before the last pressure load is increased under the corresponding loading condition, so that the micro structure on the tested sample can not further improve the wettability of the surface of the cutter along with the increase of the load under the stress corresponding to the current pressure, and the micro structure reaches or exceeds the wettability improvement limit; at this time, the pressure on the sample to be tested is not further increased, and the test is ended.

Taking the spreading speed to determine the coefficient mu_kAnd when the condition of being less than or equal to 0 occurs for the first time, the stress value of the loading position of the tested sample is used as the critical stress for regulating and controlling the wetting and spreading speed of the surface of the microstructure, and the step seven is directly carried out.

If the pressure of the loading plate on the tested sample reaches a preset limit pressure value, the spreading speed judgment coefficient mu_kIf still greater than 0, go to step five.

Step five, enabling the thicknesses H of all adjacent two liquid films_k(t) comparing every two to calculate the judgment coefficient eta of the thickness of the liquid spreading film when the pressure on the sample to be measured increases every time_kThe following were used:

taking the thickness determination coefficient eta of the liquid spreading film in the process that the pressure value of the tested sample is increased from small to small_kAnd when the condition of being less than or equal to 0 occurs for the first time, the stress value of the loading position of the measured sample is used as the critical stress for regulating and controlling the surface liquid storage property of the microstructure, and the process directly enters the step seven.

If the pressure of the loading plate on the tested sample reaches a preset limit pressure value, the determination coefficient eta of the thickness of the liquid spreading film_kIf still greater than 0, go to step six.

Step six, after increasing the limit pressure value set in the step three, repeatedly executing the step four and the step five until the mu appears_kLess than or equal to 0 or eta_kCase of ≦ 0And E, entering the step seven. Mu.s_kLess than or equal to 0 or eta_kAnd the stress value corresponding to the condition less than or equal to 0 is taken as the upper limit of the application load of the microstructure on the cutter.

Step seven, obtaining the spreading speed V of the liquid drop under the standing condition through testing₀And the thickness H of the spreading liquid film₀And calculating the spreading speed normalization index lambda under different loading conditions_xNormalized index lambda of liquid film thickness_yThe following were used:

wherein, V₀The spreading speed under the standing condition is taken as a reference value of the spreading speed; h₀The thickness of the liquid film under the standing condition is taken as a reference value of the thickness of the spreading liquid film; when V is_k(t) is much larger than the reference value, λ_x-1; when V is_kλ when (t) is equal to the reference value _x0; when V is_k(t) is much greater than the reference value, λ_x＝1；λ_yThe same can be obtained.

Normalization of the index lambda with the spreading speed under the respective different loading conditions_xAs abscissa, normalized index lambda of liquid film thickness_yAnd constructing a distribution cloud picture as a longitudinal coordinate.

Step eight, each discrete point in the distribution cloud picture respectively corresponds to the wettability and the liquid storage property of the tested sample under different stress conditions, and whether the microstructure has a remarkable regulation and control effect on the wettability of the surface of the cutter under different force loads can be evaluated. When the discrete point is positioned at the third quadrant, the microstructure is shown to completely inhibit the wettability of the surface of the cutter under the corresponding stress condition; when the discrete point is positioned at the second quadrant, the microstructure inhibits the spreading speed of the liquid drop under the corresponding stress condition, and the liquid storage property of a specific position is improved; when the discrete point is positioned in the fourth quadrant, the spreading speed of the liquid drop is improved under the corresponding stress condition by the microstructure, and the liquid storage property of a specific position is inhibited; when the values are in the first quadrant, the microstructure is shown to increase both the droplet spreading speed and the liquid retention.

If the conventional cutting fluid is tested, the real wettability detection and analysis of the surface of the cutter can be met through the process, and the following steps are further required by considering the novel green cutting fluid added with the magnetic nanoparticles.

(4) Aiming at the magnetic nano fluid, the steps of increasing the wettability detection and analysis under the action of magnetism are as follows:

and step one, returning the testing device to the initial setting, and filling the magnetic nano fluid into the dropping liquid pipe.

Step two, starting the two sample injectors and the magnetism adding module to enable the liquid drops to synchronously drip 2 microlitre of liquid drops, and adjusting the magnetic field intensity to B within 5s after dripping₁And recording the spreading length W, the spreading speed V and the thickness H of the liquid film at the final spreading position of the magnetic nano-fluid droplet.

Step three, adjusting the magnetic field intensity to be B in sequence₂，B₃，B₄，……，B_nAnd repeating the second step to obtain the spreading parameters (spreading length, spreading speed and liquid film thickness) of the magnetic nanofluid under each magnetic field strength.

And step four, replacing the pressure load change with the magnetic field strength load change by adopting a method recorded in the method of regulating and controlling the tool surface wettability by the microstructure and evaluating the regulating and controlling effect of the coupling effect of the microstructure and the magnetic field on the wettability of the magnetic nano fluid.

Further considering the full cycle test from the spreading of the cutting fluid from dripping to the formation of a liquid film to the failure of the liquid film, the following steps are required.

(5) Tool surface lubricating film acceleration test method

And step one, returning the testing device to the initial setting, and clamping the tested sample provided with the microstructure.

Step two, keeping the room temperature T_s1Starting two sample injectors at 20 ℃ to synchronously drip 2 microlitre of liquid drops on the edge of the microtexture, recording transient images and recording t₁0s, measuring the height h of the liquid film in 5 groups by extending to two sides at the highest point of the liquid film in units of 5 μm₁,h₂,h₃,……,h₂₀In the roomObtaining effective value H of the thickness of the whole liquid film at the temperature_rms。

Step three, recording the liquid film spreading image every 3S through a CCD, and recording the time t₂,t₃,t₄,……,t_nAnd calculating the effective value H of the whole liquid film thickness at the time t by using the method of the step two_rms1(t) fitting the time variation along with the thickness of the whole liquid film under the normal temperature condition into an approximate functional relation H by adopting a least square fitting method_rms1(t)＝p₁tⁿ+……+p_nAnd t is considered to be HT₁， H_rms1(t)<H_pIn time, the liquid film fails, i.e., the liquid film below this thickness does not completely cover the contact surface. Wherein H_pIt can be self-setting and is usually estimated based on the drop volume-liquid film thickness x liquid film area.

Step four, returning the testing device to the initial setting, and starting the heating module to dynamically heat (T)_s1To a set value T_s2) Starting two sample injectors to synchronously drip 2 microlitre of liquid drops on the edge of the microtexture by the double-liquid-drop method, repeating the third step, and recording and fitting the time function H of the effective value of the thickness of the liquid film_rms2(t) and obtaining a liquid film failure value H_pTime of flight HT₂。

Step five, repeating the step four, and obtaining the liquid film failure time HT at different temperatures_kObtaining a fitting relation between the liquid film life HT and the temperature T according to an Arrhenius acceleration model, wherein A and B are fitting coefficients

ln HT＝A+B/T

Step six, based on the life model fitted in the step five, calculating an acceleration coefficient of T_kTo the cutting temperature, T₀At room temperature.

And step six, comparing the acceleration coefficients of different microstructures, wherein if the acceleration coefficient is smaller, the thermal stability of the liquid film is better, and the geometric parameters corresponding to the microstructures are better.

Claims (10)

1. The utility model provides a testing arrangement of real wettability of cutter functional surface under power thermomagnetic environment which characterized in that: the device comprises a base (10), and a force-heat-magnetism loading module, a cutter clamping module, a double-liquid-drop automatic dropping module, an analysis module and a CCD recording and analyzing module which are arranged on the base (10); the base (10) is provided with a frame (1); the cutter clamping module is arranged at the top of the frame (1); the force-heat-magnetism loading module is arranged between two clamping parts of the tool clamping module and is used for applying pressure from bottom to top to a sample to be measured clamped on the tool clamping module, heating the sample to be measured and applying a magnetic field;

the dripping module bracket (2) is arranged at the top of the frame (1); the backlight lamp (3) is arranged on the side part of the dripping module bracket (2) through a backlight lamp bracket (4); the double-liquid-drop automatic dropping module is arranged at the top of the dropping module bracket (2) and is arranged downwards; the double-liquid-drop automatic dropping module is positioned right above the force-heat-magnetic loading module; the backlight lamp (3) and the CCD recording and analyzing module are respectively positioned on the opposite sides of the force-heat-magnetism loading module and are used for recording spreading images of the cutting fluid dripped on the tested sample and analyzing the contact angle change condition of the cutting fluid on the tested sample under different loading conditions;

the force-heat-magnetism loading module (800) comprises a loading plate and a jacking assembly; the loading plate is arranged on the jacking assembly; the jacking assembly is used for driving the loading plate to perform lifting movement; the loading plate can be transversely adjusted in position on the jacking assembly; the loading plate comprises a plate body, an electromagnet (801), a heat source (802) and a heat insulation plate (803); a force applying strip is arranged at the middle position of the top of the plate body; a pressure sensor is arranged between the stress application strip and the plate body; a magnetizing chamber and a heating chamber are arranged in the plate body; the heating chamber is positioned right below the stressing strip; a heat insulation plate (803) is arranged between the magnetizing chamber and the heating chamber; the heating chamber is positioned on one side of the heat insulation plate (803) close to the stress application part; an electromagnet (801) is arranged in the magnetizing cavity; a heat source (802) is mounted within the heating chamber.

2. The device for testing the real wettability of the functional surface of the cutter in the thermomagnetic environment according to claim 1, wherein: the jacking assembly comprises a servo motor (805), a speed reducer (809), a lead screw, a lifting platform (806) and a guide rail (808); a guide rail (808) which is vertically arranged is fixed on the frame (1); the lifting platform (806) and the guide rail (808) form a sliding pair; a vertically arranged lead screw is supported on the frame (1); the screw rod and a nut on the lifting platform (806) form a screw pair; the output shaft of the servo motor (805) is fixed with the input port of the reducer (809); the output shaft of the reducer (809) is fixed with the end part of the screw rod.

3. The device for testing the real wettability of the functional surface of the cutter in the thermomagnetic environment according to claim 1, wherein: the loading plate is connected to the top of the lifting platform (806) in a sliding mode along the horizontal direction, and the transverse position of the loading plate is adjusted through a precision micrometer sliding table (807); the stress application part at the top of the stress application strip is arc-shaped.

4. The device for testing the real wettability of the functional surface of the cutter in the thermomagnetic environment according to claim 1, wherein: the double-liquid-drop automatic dropping module (5) comprises a liquid drop lifting sliding table and two sample injectors; the two sample injectors are arranged on the sliding plate of the liquid dropping lifting sliding table side by side and can add cutting liquid to two sides above the stress application bar; the piston rod of the sample injector is driven by the electric sliding table.

5. The device for testing the real wettability of the functional surface of the cutter in the thermomagnetic environment according to claim 1, wherein: the CCD recording and analyzing module comprises a CCD camera and a three-axis adjusting component; the CCD camera adjusts the height and the horizontal position of the CCD camera through a three-axis adjusting assembly; the three-axis adjusting assembly comprises a scissor fork lifting mechanism used for adjusting the height and a micrometer sliding table used for the horizontal two directions.

6. A method for testing the real wettability of a functional surface of a cutter in a thermomagnetic environment is characterized by comprising the following steps: using a test device according to any one of claims 1-5; the test method comprises a test method under the condition of force loading-unloading, and comprises the following specific steps:

step one, the jacking assembly drives the loading plate to be lowered to a lower limit position, the miniature sample injector is filled with cutting fluid and then placed on the double-droplet automatic dripping module, a sample to be measured is fixed on the clamping module, the backlight plate is opened, and the height of the CCD lens is adjusted, so that the upper plane of the sample to be measured appears in an observation visual field; at this time, the loading force F of the loading plate to the sample to be measured₁When the sample is equal to 0, sticking a strain gauge on the upper surface of the sample to be measured;

step two, the jacking assembly drives the loading plate to rise, so that a stress application strip on the loading plate is in contact with the lower surface of the sample to be tested, and loading force is generated;

step three, synchronously dripping 2 microliter drops by two sample injectors of the double-drop automatic dripping module, observing and recording contact angles of the two drops on the surface of the sample to be measured by a CCD camera within 5s after dripping, and obtaining an apparent contact angle theta under the loading after calculating the average value_s，1(ii) a Meanwhile, the stress value sigma of the stressed area of the tested sample is obtained through the output signal conversion of the strain gauge₁；

Step four, the jacking assembly drives the loading plate to rise, and the loading force reaches F₂100N; at this point, step three is repeated to obtain the apparent contact angle theta under the loading_s，2(ii) a Meanwhile, the stress value sigma of the stressed area of the tested sample is obtained through the output signal conversion of the strain gauge₂；

Step five, adjusting the loading force of the jacking assembly to F₃＝500N，F₄＝1000N，F₅Stopping at 2000N, repeating step three to obtain apparent contact angle theta_s，3，θ_s，4And theta_s，5And stress value σ of the force-receiving area₃，σ₄And σ₅；

Sixthly, adopting a least square method polynomial fitting method according to (sigma)_k,θ_k) K is 1,2,. 5; fitting the contact angle under force loading conditions to an approximate functional relationship θ ═ f₁(σ)＝a₁σⁿ+……+a_n(ii) a Theta is the contact angle of the measured cutting fluid; sigma is the stress value of the tested sample in the stress area; a is₁～a_nA plurality of fitting coefficients;

step seven, the jacking assembly drives the loading plate to be lowered, and the loading force is adjusted to F₆＝1000N，F₇＝500N，F₈100N and F₉Stopping the operation when the contact angle is 1N, repeating the step three, and obtaining the apparent contact angle theta under the unloading condition₆，θ₇，θ₈And theta₉；

Step eight, similarly adopting a least square fitting method to fit the contact angle under the condition of force unloading into an approximate function relationship, wherein theta is f₂(σ)＝b₁σⁿ+……+b_n；b₁～b_nIs a fitting coefficient;

step nine, transversely adjusting the position of the loading plate to enable one sample injector to drip liquid drops at a specific distance L from a force application point, repeating the step two to the step eight to obtain a contact angle fitting approximate function relationship under the condition of force loading and unloading introducing the position relationship, wherein theta is f₃(σ,L)＝c₁σⁿ+……+c_nLⁿAnd θ ═ f₄(σ,L)＝d₁σⁿ+……+d_nLⁿ；

Step ten, predicting the real wettability change condition of the cutter to the cutter prepared by the tested sample in the cutting loading-unloading process according to the fitting function relation; the method for predicting the real wettability change includes calculating the cutting force value of the cutting edge according to the machining parameters and the geometric parameters of the cutter, calculating the stress cloud chart of the cutter surface through finite element simulation, and substituting the stress value into the function f₁Or f₃In the method, the change of the wetting angle of the cutting fluid at the blade edge and at different distances from the blade edge is obtained.

7. The test method of claim 6, wherein: the method also comprises a testing method under the condition of force-heat loading, and comprises the following specific steps:

step one, the jacking assembly drives the loading plate to rise, so that a stress application strip on the loading plate is in contact with the lower surface of the sample to be measured; at this time, the loading force reaches F₁1N; starting a heating module to a temperature T₁Keeping the temperature at 50 ℃ for 5min, starting two sample injectors, synchronously dropping 2 microliter drops by the sample injectors, observing and recording contact angles of the two drops on the surface of the sample piece within 1s after dropping, and obtaining an apparent contact angle under the loading after averaging

And detecting the stress value sigma (T) to which the sample is subjected at the moment₁)；

Step two, controlling the heating module to raise the temperature to T₂＝100℃、T₃150 ℃ and T₄After 200 ℃, repeat step one and record the apparent contact angle at each heat loading condition

And

and detecting the stress value sigma (T) corresponding to each apparent contact angle₂)、σ(T₃)、σ(T₄) (ii) a Fitting a functional relation sigma (T) of the stress value and the temperature;

the construction fits the contact angle under heat loading conditions as an approximate functional relationship as follows:

wherein the content of the first and second substances,

for the measured cutting fluid to change with temperatureAn antenna; sigma (T) is a stress value borne by a stressed area of the tested sample at the temperature of T under the preset loading force; x and K are fitting coefficients;

step three, transversely adjusting the position of the loading plate for multiple times, adjusting the distance L between the dropping position of the liquid drop and the heat source, and repeating the step one and the step two to obtain the apparent contact angle at each position

And fitting to a functional form

α₁And beta₁Two fitting parameters;

step four, controlling the heating module to reduce the temperature to T₅＝150℃、T₆100 ℃ and T₇Repeating steps one and three at 50 deg.C, fitting the apparent contact angle under the thermal unloading condition to a functional form

α₂And beta₂Two fitting parameters;

step five, adjusting the loading force of the jacking assembly to be F₂＝100N，F₃＝500N，F₄＝1000N，F₅Repeating steps one to four when the number is 2000N, and fitting the apparent contact angle under the loading and unloading conditions of force-heat into a functional form

And

and step six, predicting the real wettability of the prepared cutter surface microstructure in the cutting force-heat coupling loading-unloading process according to the fitting function relation.

8. The test method of claim 7, wherein: the method also comprises a method for analyzing and evaluating the regulation and control effect of the microstructure on the wettability of the surface of the cutter, and the method comprises the following specific steps:

clamping a tested sample provided with a microstructure same as that of a cutter on a cutter clamping module;

step two, starting the single-side sample injector to enable the liquid drop to drop 2 microliters of liquid drop to the edge position of the microstructure, observing and recording the spreading length W of the liquid drop₁(t) and liquid film thickness H₁(t) and calculating the two-dimensional spreading speed

Wherein t is time;

thirdly, adjusting the pressure of the loading plate on the sample to be measured for multiple times, so that the pressure on the sample to be measured reaches a preset limit pressure value after being adjusted for multiple times in a gradually increasing mode; the force loading point is positioned at the edge of the microstructure of the tested sample; after the pressure of the loading plate on the sample piece to be measured is adjusted each time, the step two is executed again, and the spreading length W of the liquid drop under the load is observed and obtained_k(t) liquid film thickness H_k(t) and calculating the two-dimensional spreading speed

k is the ordinal number of pressure adjustment, and the value is 2, 3.;

step four, spreading all the two adjacent two-dimensional spreading speeds V_k(t) comparing every two to calculate the spreading speed judgment coefficient mu when the pressure applied to the sample to be measured increases_kThe following were used:

mu.s of_k>0, the spreading speed of the liquid drop on the current surface of the tested sample is higher than that before the last increase of the pressure load under the corresponding loaded conditionJudging that the microstructure does not reach the limit of wettability improvement;

mu.s of_kWhen the spreading speed of the liquid drop on the current surface of the tested sample is less than or equal to the spreading speed of the liquid drop before the pressure load is increased recently under the corresponding loading condition, judging that the microstructure reaches or exceeds the limit of wettability improvement; at this time, the pressure on the sample piece to be tested is not further increased, and the test is finished;

taking the spreading speed to determine the coefficient mu_kWhen the condition of being less than or equal to 0 occurs for the first time, the stress value of the loading position of the tested sample is used as the critical stress for regulating and controlling the wetting and spreading speed of the surface of the microstructure, and the step seven is directly carried out;

if the pressure of the loading plate on the tested sample reaches a preset limit pressure value, the spreading speed judgment coefficient mu_kIf the value is still larger than 0, entering the step five;

step five, enabling the thicknesses H of all adjacent two liquid films_k(t) comparing every two to calculate the judgment coefficient eta of the thickness of the liquid spreading film when the pressure on the sample to be measured increases every time_kThe following were used:

taking the thickness determination coefficient eta of the liquid spreading film in the process that the pressure value of the tested sample is increased from small to small_kWhen the condition of being less than or equal to 0 occurs for the first time, the stress value of the loading position of the measured sample is used as the critical stress for regulating and controlling the surface liquid storage property of the microstructure, and the step seven is directly carried out;

if the pressure of the loading plate on the tested sample reaches a preset limit pressure value, the liquid film thickness judgment coefficient eta_kIf the value is still larger than 0, entering a sixth step;

step six, after increasing the limit pressure value set in the step three, repeatedly executing the step four and the step five until the mu appears_kLess than or equal to 0 or eta_kIf the condition is less than or equal to 0, entering the step seven;

step seven, obtaining the liquid drop through the test under the standing conditionSpreading speed V of₀And the thickness H of the spreading liquid film₀And calculating the spreading speed normalization index lambda under different loading conditions_xNormalized index lambda of liquid film thickness_yThe following were used:

wherein, V₀The spreading speed under the standing condition is taken as a reference value of the spreading speed; h₀The thickness of the liquid film under the standing condition is taken as a reference value of the thickness of the spreading liquid film; when V is_k(t) is much larger than the reference value, λ_x-1; when V is_kλ when (t) is equal to the reference value_x0; when V is_k(t) is much greater than the reference value, λ_x＝1；λ_yThe same can be obtained;

normalization of the index lambda with the spreading speed under the respective different loading conditions_xAs abscissa, normalized index lambda of liquid film thickness_yConstructing a distribution cloud picture as a vertical coordinate;

step eight, respectively corresponding each discrete point in the distribution cloud chart to the wettability and the liquid storage property of the tested sample under different stress conditions; when the discrete point is positioned at the third quadrant, the microstructure is shown to completely inhibit the wettability of the surface of the cutter under the corresponding stress condition; when the discrete point is positioned at the second quadrant, the microstructure inhibits the spreading speed of the liquid drop under the corresponding stress condition, and the liquid storage property is improved; when the discrete point is positioned at the fourth quadrant, the microstructure is shown to improve the spreading speed of the liquid drop under the corresponding stress condition, and the liquid storage property is inhibited; when the values are in the first quadrant, the microstructure is shown to increase both the droplet spreading speed and the liquid retention.

9. The test method of claim 8, wherein: the method also comprises a tool surface lubricating film acceleration test method, which comprises the following steps:

step one, filling magnetic nano fluid into a sample injector;

step two, starting two sample injectors and magnetizingThe module synchronously drops 2 microlitre drops and adjusts the magnetic field intensity to B within 5s after dropping₁Recording the spreading length W, the spreading speed V and the liquid film thickness H of the final spreading position of the magnetic nano fluid drop;

step three, adjusting the magnetic field intensity to be B in sequence₂，B₃，B₄，……，B_nRepeating the second step to obtain the spreading parameters of the magnetic nanofluid under the intensity of each magnetic field;

and step four, replacing the pressure load change with the magnetic field strength load change by adopting a method recorded in the method of regulating and controlling the tool surface wettability by the microstructure and evaluating the regulating and controlling effect of the coupling effect of the microstructure and the magnetic field on the wettability of the magnetic nano fluid.

10. The test method of claim 9, wherein: the method also comprises a tool surface lubricating film acceleration test method, which comprises the following steps:

clamping a sample to be tested provided with a microstructure on a cutter clamping module;

step two, keeping the room temperature T_s1Starting two sample injectors at 20 ℃ to synchronously drip 2 microlitre of liquid drops on the edge of the microtexture, recording transient images and recording t₁0s, measuring the height h of 5 groups of liquid films by taking 5 mu m as step length from the highest point of the liquid films of the two liquid drops to two sides₁,h₂,h₃,……,h₂₀Obtaining effective value H of the thickness of the whole liquid film at room temperature_rms；

Step three, recording the liquid film spreading image every 3S through a CCD, and recording the time t₂,t₃,t₄,……,t_nAnd calculating the effective value H of the whole liquid film thickness at the time t by using the method of the step two_rms1(t) similarly using least square fitting method to vary the time with the thickness of the whole liquid film under normal temperatureFitting into an approximate functional relationship, H_rms1(t)＝p₁tⁿ+……+p_nAnd t is considered to be HT₁，H_rms1(t)<H_pIn the case of the liquid film having a thickness of less than this, it is considered that the contact surface cannot be completely covered;

step four, removing the liquid film on the sample to be tested; dropping double liquid drops at the edge of the microtexture again, repeating the third step, and recording and fitting the time function H of the effective value of the liquid film thickness_rms2(t) and obtaining a liquid film failure value H_pTime of flight HT₂；

Step five, repeating the step four, and obtaining the liquid film failure time HT at different temperatures_kAccording to an Arrhenius acceleration model, the fitting relation between the liquid film service life HT and the temperature T is obtained

ln HT＝A+B/T

Wherein A and B are fitting coefficients;

step six, based on the life model fitted in the step five, calculating an acceleration coefficient of T_kTo the cutting temperature, T₀Is at room temperature;

and step six, comparing the acceleration coefficients under different microstructures, wherein the smaller the acceleration coefficient is, the better the thermal stability of the liquid film is.

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