A liquid cleaning process for oil casing machining tools

Abstract

The application relates to the technical field of high-precision liquid cleaning, and discloses a liquid cleaning process for an oil jacket pipe machining cutter. In the process, low-dielectric-constant nonpolar swelling fluid and high-dielectric-constant polar displacement fluid are alternately injected into a flow channel in a pulse mode through multi-flow-path time sequence switching, high-purity nitrogen gas is introduced into a two-phase fluid switching gap, cleaning is carried out in cooperation with a linear sweep megasonic field within a specific frequency conversion range, and finally, isopropyl alcohol steam carrier gas is introduced to carry out condensation drying. The application utilizes polar alternating time sequence switching to construct dynamic chemical potential gradient fluctuation and non-equilibrium reverse osmotic pressure at a contamination phase interface, makes an oil film crosslinked network produce periodic swelling and shrinking deformation to realize fatigue cracking, cooperates with local micro area temperature rise of the linear sweep sound field to in-situ precipitate nanoscale microemulsion droplets to construct a repulsive hydrostatic pressure wedge, effectively eliminates a fluid mechanics boundary layer barrier and destroys capillary binding force, and removes composite contamination bodies in micro-geometric dead angles.

Description

Technical Field

[0001] This invention belongs to the field of high-precision liquid cleaning technology, and in particular relates to a liquid cleaning process for oil casing machining tools. Background Technology

[0002] Cleaning oil stains and impurities from workpiece surfaces typically employs methods such as solvent immersion, cleaning fluid spraying, and acoustic-assisted stripping. These methods utilize the wetting effect of the cleaning fluid on the workpiece surface and the scouring action of the fluid flow to remove contaminants. For workpieces with chip grooves, small pores, and micro-cracks in the coating, existing cleaning processes mainly rely on the penetration and exchange of the cleaning fluid in these areas, as well as the impact of fluid flow or acoustic fields, to remove exposed oil stains and impurities. During high-speed cutting, oil sleeve machining tools generate and accumulate heat, causing the organic components in the cutting fluid to undergo thermal cross-linking and polymerization, which then accumulates in the chip grooves. A high-viscosity solidified oil film layer forms at the bottom and deep within the microcracks of the coating. This solidified oil film layer encapsulates fine alloy debris, causing the oil film and debris to adhere firmly to the tool surface. When the cleaning fluid approaches the chip removal groove and the wall of the small pores, the flow rate is significantly reduced due to the influence of the wall boundary layer, making it difficult to fully contact and exchange with the deep contaminants. This easily leads to mass transfer blind zones and acoustic shadow zones. At the same time, capillary action within the small pores hinders the replacement of the cleaning fluid, and the solidified oil film layer also fixes the debris within the pores or cracks, making it difficult for the cleaning action to reach the deep contact position between the oil film and the tool surface.

[0003] Existing cleaning processes typically enhance cleaning effectiveness by increasing spray pressure, extending soaking time, or using more corrosive cleaning media. However, these methods still fail to fully swell the solidified oil film layer or reduce capillary binding within tiny pores. Simply increasing the rinsing pressure results in localized deposition of fine debris due to the lack of force to detach it from the oil film and tool surface, which can easily lead to stress concentration on the cutting edge. Increasing the corrosiveness of the cleaning media or using strong rinsing can increase the risk of hydrogen embrittlement and surface coating peeling on the tool substrate. It is difficult to simultaneously achieve both deep dirt removal and tool surface protection.

[0004] Therefore, the technical problem to be solved by this invention is to reduce the limitations of the wall boundary layer and capillary action on the penetration and exchange of cleaning fluid, and to enable the deep solidified oil film layer and fine alloy debris to actively detach and be effectively replaced and discharged while maintaining the integrity of the tool substrate and coating. Summary of the Invention

[0005] This invention aims to solve the problem of non-destructive removal of deep composite contamination in complex geometric structures by overcoming the hydrodynamic boundary layer barrier and capillary confinement.

[0006] In this technical solution, a liquid cleaning process for oil casing machining tools includes the following steps:

[0007] Step S101: Inject a low dielectric constant nonpolar swelling fluid at a temperature of 50°C to 55°C into the surface of the oil casing machining tool, followed by injecting a high dielectric constant polar displacing fluid at a temperature of 20°C to 25°C. The fluids alternately penetrate the solidified oil film layer on the surface of the oil casing machining tool, and a transient temperature step of 28°C to 32°C is generated in the solidified oil film layer to weaken the adhesion between the solidified oil film layer and the substrate surface of the oil casing machining tool.

[0008] Step S102: Apply a linear sweep frequency megasonic wave field to the surface of the oil casing machining tool, use continuous frequency conversion acoustic flow to eliminate the acoustic shadow area in the chip removal groove of the oil casing machining tool, and induce local temperature rise in the deep crack of the solidified oil film layer. When the local temperature rise reaches the cloud point threshold of the unsaturated additive, nano-sized microemulsion droplets are precipitated in situ. The nano-sized microemulsion droplets gather towards the fine alloy debris and coating gaps, and the fine alloy debris is desorbed by the micro-jet generated by the rupture of cavitation bubbles.

[0009] In step S103, isopropanol vapor is introduced into the surface of the oil casing machining tool. The isopropanol vapor undergoes local condensation on the inner wall of the oil casing machining tool to form a continuous liquid film. The surface tension difference between the continuous liquid film and the residual moisture is used to construct a Marangoni surface tension gradient in the longitudinal direction of the flow channel of the oil casing machining tool. The Marangoni surface tension gradient generates a longitudinal driving force to pull the residual moisture towards the outlet of the flow channel and discharge it.

[0010] Preferably, step S102 includes the following sub-steps: step S1021, controlling the frequency of the linearly swept megasonic wave field to be linearly swept within 0.8MHz to 1.2MHz, and emitting megasonic waves to the surface of the oil casing machining tool; step S1022, using the linearly swept megasonic wave field to induce a local temperature rise deep in the crack, and when the local temperature rise reaches the cloud point threshold of 45°C to 50°C, nano-sized microemulsion droplets are precipitated from the unsaturated additive.

[0011] Preferably, before step S101, the method further includes the following steps: under the conditions of a coarse cleaning pressure of 2 MPa to 5 MPa and a coarse cleaning temperature of 40°C to 45°C, a coarse cleaning agent composed of oligomeric surfactants and organic solvents is circulatedly sprayed onto the surface of the oil casing machining tool to flush the surface of the oil casing machining tool to expose the cured oil film layer.

[0012] Preferably, the low dielectric constant nonpolar swelling fluid is a mixture of isoalkanes with 10 to 14 carbon atoms and cycloalkanes in a mass ratio of 3:1, and the high dielectric constant polar displacement fluid is a mixture of ethylene glycol monobutyl ether and deionized water in a mass ratio of 1:4.

[0013] Preferably, the fluid management process further includes the following steps: Step S501, during the continuous repetitive liquid cleaning process, a photoelectric sensor installed in the drain pipe collects the real-time absorbance value of the residual liquid discharged by the high dielectric constant polar driving fluid, and establishes an absorbance time series according to the number of cleaning cycles; Step S502, the first derivative of the absorbance time series is calculated to obtain the rate parameter of absorbance change with the number of cleaning cycles; Step S503, when the rate parameter of change exceeds the preset degradation judgment threshold, an automatic liquid replacement command for the high dielectric constant polar driving fluid is output to the external valve control unit.

[0014] Preferably, step S103 specifically includes the following sub-steps: step S1031, controlling the flow rate of isopropanol vapor introduced into the oil casing to the surface of the machining tool to be 15L / min to 20L / min, and controlling the temperature of the isopropanol vapor to be 82°C to 85°C; step S1032, maintaining the temperature of the inner wall surface to be 25°C to 30°C, so that the temperature difference between the isopropanol vapor and the inner wall surface is maintained at 52°C to 60°C, forming a continuous liquid film with a thickness of 5μm to 10μm on the inner wall surface.

[0015] Preferably, the oil casing machining tool includes a tool base made of tungsten cobalt cemented carbide, and the surface of the oil casing machining tool is covered with a hard coating; the hard coating is made of aluminum titanium nitride or chromium aluminum nitride, and the thickness of the hard coating is 2μm to 5μm.

[0016] Preferably, the unsaturated additive is a compound composed of fatty alcohol polyoxyethylene ether and unsaturated fatty acids, and the mass percentage concentration of the unsaturated additive in the cleaning solution is 0.5% to 1.2%; the cloud point threshold is 45°C to 48°C, and the average particle size of the nano-sized microemulsion droplets is 50nm to 150nm.

[0017] Preferably, after step S103, the following quality inspection step is also included: using an optical microscopic imaging sensor located above the chip removal groove of the oil casing machining tool to acquire a real-time residual image of the surface of the oil casing machining tool, and comparing the real-time residual image with the calibrated clean surface reference image, and outputting a cleaning completion signal when the image overlap is not less than 98%.

[0018] Compared with existing technologies, the liquid cleaning process for oil casing machining tools of the present invention has the following advantages:

[0019] 1. In the liquid cleaning process of oil casing machining tools, by alternating the action of low dielectric constant nonpolar swelling fluid and high dielectric constant polar driving fluid, and by using high-purity nitrogen gas flow to reduce the influence of residual liquid film when switching between the two fluids, the solidified oil film layer can be repeatedly swollen and contracted, gradually reducing its structural strength and adhesion stability. This can cause the high viscosity solidified oil film layer to crack and peel off from the tool surface, reduce the restriction of the wall boundary layer on the penetration and exchange of cleaning fluid, and improve the removal effect of deep oil stains in chip removal grooves and small pores.

[0020] 2. By utilizing the temperature difference between the low dielectric constant nonpolar swelling fluid and the high dielectric constant polar driving fluid, the cured oil film layer undergoes an instantaneous temperature change. The difference in the degree of thermal deformation of the cured oil film layer, hard coating, and tool substrate weakens the adhesion between the cured oil film layer and the tool surface. This method helps to remove the fixing effect of the cured oil film layer on chips deep in the chip groove and in the coating microcracks, while reducing the damage to the tool substrate and hard coating caused by simply increasing the flushing pressure or the corrosiveness of the medium.

[0021] 3. The linear sweep frequency megaacoustic field can reduce the acoustic shadow zone formed by uneven sound field distribution in chip removal grooves and complex gaps, making it easier for acoustic energy to act on the deep cracks of the solidified oil film layer. After the local temperature rise causes the unsaturated additive to precipitate nano-sized microemulsion droplets, the nano-sized microemulsion droplets can enter between the fine alloy debris and the gaps in the coating. Combined with the micro-jet generated by the rupture of cavitation bubbles, the capillary binding and fixing effect of the solidified oil film layer on the debris is weakened, thereby improving the ability of fine alloy debris to detach and be discharged from chip removal grooves, micro-cracks and other narrow parts. Attached Figure Description

[0022] Figure 1 This is a flowchart of the fluid cleaning control process of the present invention;

[0023] Figure 2 This is a process diagram for cleaning composite contaminants according to the present invention. Detailed Implementation

[0024] The technical solutions in the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0025] A liquid cleaning process for oil casing machining tools includes the following steps:

[0026] Step S101: Inject a low dielectric constant nonpolar swelling fluid at a temperature of 50°C to 55°C into the surface of the oil casing machining tool, followed by injecting a high dielectric constant polar displacing fluid at a temperature of 20°C to 25°C. The fluids alternately penetrate the solidified oil film layer on the surface of the oil casing machining tool, and a transient temperature step of 28°C to 32°C is generated in the solidified oil film layer to weaken the adhesion between the solidified oil film layer and the substrate surface of the oil casing machining tool.

[0027] Step S102: Apply a linear sweep frequency megasonic wave field to the surface of the oil casing machining tool, use continuous frequency conversion acoustic flow to eliminate the acoustic shadow area in the chip removal groove of the oil casing machining tool, and induce local temperature rise in the deep crack of the solidified oil film layer. When the local temperature rise reaches the cloud point threshold of the unsaturated additive, nano-sized microemulsion droplets are precipitated in situ. The nano-sized microemulsion droplets gather towards the fine alloy debris and coating gaps, and the fine alloy debris is desorbed by the micro-jet generated by the rupture of cavitation bubbles.

[0028] In step S103, isopropanol vapor is introduced into the surface of the oil casing machining tool. The isopropanol vapor undergoes local condensation on the inner wall of the oil casing machining tool to form a continuous liquid film. The surface tension difference between the continuous liquid film and the residual moisture is used to construct a Marangoni surface tension gradient in the longitudinal direction of the flow channel of the oil casing machining tool. The Marangoni surface tension gradient generates a longitudinal driving force to pull the residual moisture towards the outlet of the flow channel and discharge it.

[0029] Preferably, step S102 includes the following sub-steps: step S1021, controlling the frequency of the linearly swept megasonic wave field to be linearly swept within 0.8MHz to 1.2MHz, and emitting megasonic waves to the surface of the oil casing machining tool; step S1022, using the linearly swept megasonic wave field to induce a local temperature rise deep in the crack, and when the local temperature rise reaches the cloud point threshold of 45°C to 50°C, nano-sized microemulsion droplets are precipitated from the unsaturated additive.

[0030] Preferably, before step S101, the method further includes the following steps: under the conditions of a coarse cleaning pressure of 2 MPa to 5 MPa and a coarse cleaning temperature of 40°C to 45°C, a coarse cleaning agent composed of oligomeric surfactants and organic solvents is circulatedly sprayed onto the surface of the oil casing machining tool to flush the surface of the oil casing machining tool to expose the cured oil film layer.

[0031] Preferably, the low dielectric constant nonpolar swelling fluid is a mixture of isoalkanes with 10 to 14 carbon atoms and cycloalkanes in a mass ratio of 3:1, and the high dielectric constant polar displacement fluid is a mixture of ethylene glycol monobutyl ether and deionized water in a mass ratio of 1:4.

[0032] Preferably, the fluid management process further includes the following steps: Step S501, during the continuous repetitive liquid cleaning process, a photoelectric sensor installed in the drain pipe collects the real-time absorbance value of the residual liquid discharged by the high dielectric constant polar driving fluid, and establishes an absorbance time series according to the number of cleaning cycles; Step S502, the first derivative of the absorbance time series is calculated to obtain the rate parameter of absorbance change with the number of cleaning cycles; Step S503, when the rate parameter of change exceeds the preset degradation judgment threshold, an automatic liquid replacement command for the high dielectric constant polar driving fluid is output to the external valve control unit.

[0033] Preferably, step S103 specifically includes the following sub-steps: step S1031, controlling the flow rate of isopropanol vapor introduced into the oil casing to the surface of the machining tool to be 15L / min to 20L / min, and controlling the temperature of the isopropanol vapor to be 82°C to 85°C; step S1032, maintaining the temperature of the inner wall surface to be 25°C to 30°C, so that the temperature difference between the isopropanol vapor and the inner wall surface is maintained at 52°C to 60°C, forming a continuous liquid film with a thickness of 5μm to 10μm on the inner wall surface.

[0034] Preferably, the oil casing machining tool includes a tool base made of tungsten cobalt cemented carbide, and the surface of the oil casing machining tool is covered with a hard coating; the hard coating is made of aluminum titanium nitride or chromium aluminum nitride, and the thickness of the hard coating is 2μm to 5μm.

[0035] Preferably, the unsaturated additive is a compound composed of fatty alcohol polyoxyethylene ether and unsaturated fatty acids, and the mass percentage concentration of the unsaturated additive in the cleaning solution is 0.5% to 1.2%; the cloud point threshold is 45°C to 48°C, and the average particle size of the nano-sized microemulsion droplets is 50nm to 150nm.

[0036] Preferably, after step S103, the following quality inspection step is also included: using an optical microscopic imaging sensor located above the chip removal groove of the oil casing machining tool to acquire a real-time residual image of the surface of the oil casing machining tool, and comparing the real-time residual image with the calibrated clean surface reference image, and outputting a cleaning completion signal when the image overlap is not less than 98%.

[0037] Example 1: In continuous cutting operations of oil sleeve machining tools with a tungsten-cobalt cemented carbide base and a 2μm to 5μm thick aluminum titanium nitride or chromium aluminum nitride hard coating, localized heat accumulation in the chip flute area triggers a high-temperature cross-linking polymerization reaction of organic components in the cutting fluid. This results in the formation of a high-viscosity solidified oil film layer deep within the fine cracks and pores of the chip flute base and the hard coating. This solidified oil film layer encapsulates fine alloy chips, forming a composite contaminant with strong adhesion. Removing residual contaminants from such geometric surfaces and internal porous pores faces mass transfer resistance. Spraying or solvent immersion processes are limited by the hydrodynamic boundary layer barrier effect of the solid surface, and the cleaning medium is close to the chip flute. The flow velocity at the depth of the groove and the wall of the fine crack attenuates to near zero, forming a mass transfer blind zone. The capillary binding force inside the micropores causes the solidified oil film to mechanically pin the alloy debris. If the external physical flushing pressure is increased or the chemical corrosiveness of the medium is increased, the complex contaminants in the mass transfer blind zone cannot be removed due to the lack of active desorption force between the phase interfaces. Instead, it will cause physical damage risks such as hydrogen embrittlement of the tool substrate and peeling of the hard coating. This leads to a trade-off between maintaining the integrity of the tool substrate and removing deep contaminants. The liquid cleaning process for oil casing machining tools adopts the phase interface peeling and hydrodynamic replacement method of solidified residues inside the porous medium. It removes the mass transfer blind zone by changing the chemical potential and thermal stress state of the phase interface.

[0038] After clamping and limiting the oil casing machining tool to be cleaned at the center of the flow channel, the cleaning system, under the conditions of a rough cleaning pressure of 2MPa to 5MPa and a rough cleaning temperature of 40℃ to 45℃, circulates and sprays a rough cleaning agent composed of oligomeric surfactants and organic solvents onto the surface of the oil casing machining tool. When preparing the rough cleaning agent, the oligomeric surfactants are added to the organic solvent and mixed evenly. After confirming that the mixture does not separate or precipitate at the rough cleaning temperature, it is used for circulation spraying, allowing the rough cleaning agent to continuously wet the tool surface and remove loose oil stains until the oil hardens. After the film layer is exposed, the control unit for multi-flow-path timing switching regulates the flow-path switching valves to inject a low-dielectric-constant non-polar swelling fluid at a temperature of 50°C to 55°C onto the surface of the oil casing machining tool. This low-dielectric-constant non-polar swelling fluid is a mixture of isoalkanes and cycloalkanes with 10 to 14 carbon atoms in a 3:1 mass ratio. The non-polar, lipophilic long-chain molecules in this fluid penetrate into the cross-linked polymer backbone of the solidified oil film layer, increasing the free volume of polymer segments and reducing the cohesive energy density between molecular chains. The first flow path is then closed and the gas phase flow path is opened, introducing pressure. A high-purity nitrogen gas flow of 0.4 MPa is continuously maintained over the surface of the oil casing machining tool for 1.5 seconds to purge and thin the residual adhering liquid film inside the flow channel, establishing a non-equilibrium reverse osmotic pressure and dynamic chemical potential gradient fluctuation at the phase interface of the solidified oil film layer. The gas phase flow path is closed and the third flow path is opened, injecting a high dielectric constant polar displacement fluid at a temperature of 20℃ to 25℃ in a pulse manner. The high dielectric constant polar displacement fluid is a mixture of ethylene glycol monobutyl ether and deionized water in a mass ratio of 1:4. The oleophobic repulsion effect of the polar molecules dissipates the residual non-polar... The medium undergoes local self-condensation and is squeezed into the porous pores. The temperature difference between the high dielectric constant polar driving fluid and the low dielectric constant nonpolar swelling fluid generates a transient temperature step of 28°C to 32°C in the solidified oil film layer. Due to the difference in the intrinsic thermal expansion coefficients between the solidified oil film layer, the underlying hard coating, and the tool substrate, a non-uniform thermal stress shear field is generated. The thermal stress shear force directly weakens and cuts off the weak van der Waals interaction between the solidified oil film layer and the surface of the oil casing machining tool, thereby weakening the adhesion between the solidified oil film layer and the surface of the oil casing machining tool substrate.

[0039] On the surface of a tool used in oil casing machining, a transient temperature jump of 28°C to 32°C can form and be maintained in a short time. The heat transfer resistance and thermal equilibrium mechanism are as follows: Although the tool substrate made of tungsten-cobalt cemented carbide itself has extremely high thermal conductivity, the solidified oil film layer attached to its surface is formed by thermal cross-linking and polymerization of the organic components of the cutting fluid. Its intrinsic thermal conductivity is lower than that of the metal substrate, forming a natural thermal resistance boundary layer. When the low dielectric constant nonpolar swelling fluid at a temperature of 50°C to 55°C is pulsedly switched to the high dielectric constant polar driving fluid at a temperature of 20°C to 25°C, the alternating intrusion of the fluids brings about intense surface convection heat transfer. Since the solidified oil film layer is only micrometer thick and has an internal heat transfer delay effect, within the millisecond window period of the instantaneous replacement of the two-phase fluids, the outer surface temperature of the oil film drops rapidly following the high dielectric constant polar driving fluid. However, the bottom layer of the oil film, due to its close contact with the tool substrate which has a huge heat sink effect, remains stable for a very short time. Maintaining a high temperature state close to that of the preceding low-dielectric-constant nonpolar swelling fluid, a transient temperature step of 28°C to 32°C is formed and maintained for a short time along the normal direction within a very small thickness span of the oil film layer. This transient temperature step serves as a transient control window on the process time axis, which is bound to the characteristic input parameter of the fluid switching step response time collected by the thermocouple sensor in the feed pipe. Through the time-sharing control valve group of the main circulation pump, the process action of blocking the low-dielectric-constant nonpolar swelling fluid and seamlessly injecting the high-dielectric-constant polar displacement fluid within 0.005s to 0.015s causes a convective transient response with a cooling rate of 2000°C per second to occur on the outer surface of the oil film. A non-equilibrium temperature difference state with a duration of 0.01s to 0.03s and a constant amplitude of 28°C to 32°C is output on the normal of the oil film spatial cross-section. The non-uniform thermal stress caused by this is used to directly shear the weak interaction force between the oil film and the tool substrate.

[0040] During the alternating injection of low-dielectric-constant nonpolar swelling fluid and high-dielectric-constant polar displacing fluid, the emitting end of the acoustic energy sweeping radiation source is directed towards the opening of the chip removal groove, allowing megasonic waves to cover the chip removal groove and the cracked area of ​​the hard coating. The frequency of the linearly swept megasonic wave field is controlled to continuously and reciprocally sweep linearly within the range of 0.8MHz to 1.2MHz. The sweeping period and output power are adjusted according to the structure of the chip removal groove, causing the low sound pressure regions corresponding to different frequencies to move sequentially within the chip removal groove. The continuous frequency-converting acoustic flow eliminates the acoustic shadows fixed within the chip removal groove. The continuous frequency-converting acoustic flow is a discrete secondary acoustic flow generated by the ultrasonic transducer radiating plate receiving high-frequency alternating current. It relies on the transducer's output power of 150W to 250W and a linear sweep frequency period of 0.05s to 0.15s as its characteristic input parameters. Through a process where high and low sound pressure nodes continuously displace along the axial flow channel of the chip removal groove at a speed of 3.5 meters per second within the sweep frequency period, it disrupts the fixed nodes of the standing waves in the narrow geometric space of the sound field. This results in a closed-loop output fluid dynamic boundary layer thickness ranging from 1... The discrete thinning shear state, reducing the thickness from 5μm to below 2μm, was used to collect local temperatures at locations corresponding to the cracked areas of the hard coating. Based on the collected data, the output power or duration of the linear sweep frequency megasonic field was adjusted to bring the local temperature deep within the crack to 45℃ to 50℃. When the local temperature reached the cloud point threshold of the unsaturated additive (45℃ to 48℃), nano-sized microemulsion droplets precipitated in situ from the unsaturated additive, which was a compound composed of fatty alcohol polyoxyethylene ether and unsaturated fatty acids, in the cleaning solution. The mass percentage concentration in the cleaning solution is 0.5% to 1.2%, and the average particle size of the precipitated nano-sized microemulsion droplets is 50 nm to 150 nm. The nano-sized microemulsion droplets gather towards the gaps between the fine alloy debris and the coating, and penetrate into the mechanical pinning angle between the alloy debris and the coating gaps to gather. A hydrostatic wedge is formed inside the gap to overcome the capillary binding force of the solidified oil film on the debris. The micro-jet generated by the rupture of cavitation bubbles drives the desorption of fine alloy debris, causing the deeply embedded metal particles to desorb and be discharged outward with the mainstream fluid.

[0041] After alternating injection of low-dielectric-constant nonpolar swelling fluid and high-dielectric-constant polar displacing fluid, and cleaning with a linear sweep frequency megasonic field, for oil casing machining tools with flow channels, the drying system introduces isopropanol vapor into its surface and flow channels, controlling the flow rate of isopropanol vapor at 15 L / min to 20 L / min and the temperature of isopropanol vapor at 82°C to 85°C; maintaining the temperature of the inner wall surface of the flow channels of the oil casing machining tool at 25°C to 30°C, so that the isopropanol vapor reacts with the inner wall surface. Maintaining a temperature difference of 52°C to 60°C, a continuous liquid film with a thickness of 5μm to 10μm is formed on the inner wall of the flow channel. Isopropanol vapor undergoes local condensation on the inner wall of the flow channel of the oil casing machining tool to form a continuous liquid film. Utilizing the surface tension difference between the continuous liquid film and the residual moisture, a Marangoni surface tension gradient is constructed in the longitudinal direction of the flow channel. The Marangoni surface tension gradient generates a longitudinal driving force, which pulls the residual moisture to converge and be discharged towards the outlet of the flow channel, thus completing the dehydration and drying without residual water film.

[0042] When comparing the real-time residual image with the calibrated clean surface reference image, the digital signal processor (DSP) performs the following data processing steps: The optical microscopic imaging sensor inputs the acquired real-time residual image into the DSP in the form of a two-dimensional pixel matrix. The DSP extracts the grayscale value of each pixel in the real-time residual image and compares it point by point with the grayscale value of the corresponding coordinate pixel in the pre-stored calibrated clean surface reference image. The processor calculates the proportion of pixels with completely identical grayscale values ​​in the two images to the total number of pixels, and converts the multi-dimensional image matrix into a percentage value representing the image overlap. When the percentage value reaches or exceeds 98%, the logic judgment unit inside the processor triggers and outputs a high-level signal as a cleaning completion signal to terminate the subsequent cleaning process, remove residual water film and composite contaminants in the chip removal groove and geometric dead corners, eliminate the source of local stress concentration caused by metal chip deposition on the tool cutting edge, inhibit the expansion of microcracks in the hard coating under subsequent heavy-load cutting conditions, maintain the integrity of the tool's geometric characteristics, and extend the regeneration service life of the machining tool under harsh heavy-load conditions.

[0043] In the continuous liquid cleaning process, a photoelectric sensor installed in the drain pipe collects the real-time absorbance value of the residual liquid discharged by the high dielectric constant polar driving fluid. The control system uses the absorbance value as input data and stores it sequentially according to the cleaning cycle number, thus establishing an absorbance time sequence in the memory. The digital signal processor in the control system reads the sequence periodically and performs subtraction difference operation on the absorbance values ​​of two adjacent cycles in the sequence to complete the first-order differential calculation, thereby obtaining the parameter of the rate of change of absorbance with the number of cleaning cycles. When the rate of change parameter exceeds the preset degradation judgment threshold, this degradation judgment threshold is configured in the internal comparison register of the main control microprocessor. It is bound to the characteristic input parameter of transmittance attenuation coefficient collected by the photoelectric sensor at a wavelength of 650nm. Its underlying data flow topology is based on the first-order differential... The differential calculation register directly outputs the current rate of change parameter stream, which is imported into the first input terminal of the hardware comparator module via the internal data bus. The hardware comparator module executes a control flow action that compares the current rate of change parameter stream with the discrete value of absorbance increasing by 0.05 per cycle pre-stored in the comparison register to determine the size of the conditional branch. When the jump condition of greater than the discrete value is met, the state machine transition is triggered, and the closed-loop output automatic liquid replacement flag register flips from zero to one, indicating that the turbidity of cross-linked polymer products and suspended metal particles in the residual liquid has reached the replacement boundary. The digital signal processor generates a high-level control signal as an automatic liquid replacement command for high dielectric constant polarity driving fluid, and outputs the signal to the external valve control unit. The external valve control unit switches the pipeline valve state to execute automatic liquid replacement, completing the closed-loop control of fluid management.

[0044] Example 2: In the sealed cleaning chamber of the flow system test bench, the time control window parameters of the oil casing machining tool coated with high-temperature cross-linked polymer products and hard coating were calibrated. The flow controller adjustment resolution was set to 0.01 L / min, the pressure transmitter measurement accuracy was 0.005 MPa, and the frequency control resolution of the acoustic energy sweep radiation source was 1 kHz to collect fluid flow state parameters during the alternating cleaning process of multiphase flow. When the valve group state machine controls the alternating injection of low dielectric constant nonpolar swelling fluid and high dielectric constant polar displacing fluid, the time control window parameters are mainly determined based on the slope of the boundary velocity change within a single pulse cycle and the mass transfer diffusion rate of the polymer network phase interface. When the pulse duration is too long, the shear force of the cleaning medium near the deep wall of the chip removal groove gradually decreases, and the static mass transfer boundary layer reforms. When the pulse duration is too short, the fluid has not fully wetted and entered the deep pore layer. Therefore, the time control window takes into account both the dynamic destruction frequency of the fluid dynamic boundary layer and the displacement process of the two-phase liquid in the confined pore.

[0045] During the frequency switching process, the shear stress on the tool surface is characterized by the total pressure drop of the closed flow channel. When the surface shear stress is greater than the initial phase boundary adhesion resistance of the solidified oil film, the pulse injection duration of the low dielectric constant nonpolar swelling fluid and the high dielectric constant polar displacement fluid is adjusted to the lower limit of the parameter range to maintain the dynamic chemical potential gradient fluctuation in the closed cleaning chamber. When the total flow rate of the closed flow channel is 3.0 L / min to 3.5 L / min and the pressure pulsation disturbance with the mainstream superposition amplitude of the cleaning fluid is 0.03 MPa, the pulse injection duration of the low dielectric constant nonpolar swelling fluid is set to 5 s, the pulse injection duration of the high dielectric constant polar displacement fluid is set to 5 s, and the duration of the gas phase fluid isolation medium introduced into the two-phase switching gap is set to 1.5 s.

[0046] During continuous alternating pulse injection and gas phase isolation, the control unit switches each flow path in a time-sharing sequence, using the total pressure drop and flow rate signals collected in real time by the pressure transmitter and flow meter located at the flow channel inlet as the state switching criteria. When the pulse injection of the low dielectric constant non-polar swelling fluid reaches 5s and the total pressure drop fluctuation of the flow channel enters the preset steady-state range, the control unit closes the first flow path valve. During the transition phase from the closure of the first flow path valve to the full opening of the gas phase flow path valve, the main pump maintains constant pressure closed-loop operation to reduce pipeline liquid hammer and instantaneous system pressure loss caused by flow interruption. When the continuous injection of gas phase fluid reaches 1.5s, the control unit closes the gas phase valve and releases the residual gas phase pressure in the flow channel through the venting circuit. Then, the third flow path valve is opened to inject the high dielectric constant polar drive fluid in a pulse manner. The above time-sharing switching and pressure transition process is used to prevent gas from entering the liquid phase pump body and to prevent system overload and detection failure caused by the mixing of the two liquid phases.

[0047] Under the same environmental conditions, test groups 1, 2, and 3 of this method, a continuous spray control group, a control group without temperature difference step, a control group without additives, a group exceeding the lower limit boundary, and a group exceeding the upper limit boundary were set up respectively. A center frequency offset noise of 50 kHz was superimposed in a linear sweep frequency megasonic field to examine the cleaning state of each group under the applied frequency disturbance. The oil casing processing tools used in the experiment were all made of tungsten cobalt cemented carbide tool base, and their surfaces were covered with aluminum titanium nitride hard coating with a thickness of 2 μm to 5 μm. The initial cured oil film thickness on the chip removal groove surface of the test groups of this method was set to 5 μm, 15 μm, and 35 μm respectively, and the process was cycled 20 times according to the above process.

[0048] The continuous spray control group continuously sprayed the liquid cleaning medium under a constant pressure of 2 MPa; the temperature-step-free control group maintained its temperature at 25°C when a high dielectric constant polar displacement fluid was introduced to eliminate the 30°C temperature step; the additive-free control group removed unsaturated additives with a mass percentage concentration of 0.5% to 1.2% from the cleaning liquid; the lower limit boundary group shortened the pulse injection duration of both the low dielectric constant nonpolar swelling fluid and the high dielectric constant polar displacement fluid to 1 s, and shortened the duration of the gas phase fluid isolation medium to 0.2 s; the upper limit boundary group extended the pulse injection duration of both phase fluids to 30 s, and extended the duration of the gas phase fluid isolation medium to 10 s.

[0049] After each group's operation, real-time residual images of the tool surface during oil casing machining were acquired using an optical microscopic imaging sensor located above the chip removal groove. The real-time residual images were then compared point-by-point with a calibrated clean surface reference image within a digital signal processor to calculate the image overlap. Simultaneously, the desorption rate of alloy debris encased within the cured oil film was determined using a mass difference weighing method. Recorded parameters included the initial cured oil film thickness on the oil casing machining tool surface. The transient thermal stress shear force generated at the interface between the solidified oil film and the underlying hard coating during the transition between the two fluids. The residual oil film thickness measured in the mass transfer blind zone of the chip removal groove after the fluid displacement procedure is completed. Image overlap between real-time residual images and calibrated clean surface reference images and alloy debris desorption rate .

[0050] This method was tested in test group one. The interface is 15 μm thick. After alternating between the two fluids, the interface... The pressure is 2.15 MPa; after the fluid displacement procedure is completed, the mass transfer blind zone of the chip removal tank is... The residue level was reduced to 1.12 μm. Based on this, the real-time residual image was compared with the calibrated clean surface reference image. The result was 99.2%, obtained through the mass difference weighing method. It is 98.4%.

[0051] This method was tested in test group two. The thickness is 5μm, and after the same process, the interface... The pressure is 2.08 MPa, within the mass transfer blind zone of the chip conveyor. It is 0.35μm; the corresponding It is 99.7%. It is 99.5%.

[0052] This method was tested in test group three. The thickness is 35 μm, generated by switching between the two fluids. The pressure was 2.21 MPa after fluid displacement. It is 2.54 μm; the corresponding It is 98.1%. The overlap rate was 96.2%. As the initial cured oil film layer thickened, the mass transfer resistance of the deep porous structure increased, and the residual oil film thickness increased accordingly. The image overlap of the three test groups using this method remained above 98%.

[0053] Each control group Both were 15 μm. The continuous spray control group did not switch the temperature difference between the two fluids. At the interface... 0 MPa, after fluid displacement It is 13.84 μm. It is 41.5%. At 12.3%, the group relied solely on continuous liquid flow scouring, and the hydrodynamic boundary layer on the solid surface still limited the transmission of the cleaning medium to the depths of the chip removal groove.

[0054] The control group without temperature step maintained the high dielectric constant polar displacement fluid at 25°C. After eliminating the 30°C temperature step, the interface... It is 0.12 MPa. It is 9.42 μm. It was 62.3%. The percentage was 54.1%, indicating that the transient thermal stress shear effect was weakened in this control group, and the adhesion between the solidified oil film layer and the tool substrate was not sufficiently weakened.

[0055] The additive-free control group maintained the alternation of the two fluids at the interface. The pressure was 2.11 MPa; because no unsaturated additives were added to the cleaning fluid, a hydrostatic wedge formed by the aggregation of nano-sized microemulsion droplets did not form deep within the crack, and the pressure was reduced after fluid replacement. It is 7.15μm. It was 74.6%. It is 68.2%.

[0056] The lower limit boundary group shortens the pulse injection duration of the two-phase fluid to 1 s and the duration of the gas-phase fluid isolation medium to 0.2 s. The interface of this group... The pressure is 0.84 MPa after fluid displacement. It is 10.23 μm. It was 58.1%. The rate was 47.6%, and the alternation period was shorter than the time required for the fluid to enter the chip removal groove along the flow channel and penetrate into the coating gaps, resulting in insufficient displacement of the two-phase liquid in the confined pores.

[0057] The upper limit boundary group extends the pulse injection duration of the two-phase fluid to 30 s and the duration of the gas-phase fluid isolation medium to 10 s. The interface of this group... The pressure is 2.13 MPa after fluid displacement. It is 6.84μm. It was 76.2%. At 71.3%, as the pulse duration is extended, the multiphase fluid in the mass transfer blind zone gradually approaches quasi-static equilibrium, the chemical potential gradient fluctuation at the phase interface weakens, and the cleaning efficiency decreases as the control cycle continues to increase.

[0058] The above data indicate that when alternating injections of low-dielectric-constant nonpolar swelling fluid and high-dielectric-constant polar displacing fluid, transient temperature steps between the two-phase fluids, a linear sweep frequency megasonic field, and nanoscale microemulsion droplets precipitated in situ from unsaturated additives work together, the fluid can enter the chip removal groove and coating gaps, weakening the adhesion and capillary binding of the solidified oil film layer, and displacing and discharging the composite contaminants with the fluid. When the pulse duration is too short, the two-phase liquids cannot complete deep displacement; when the pulse duration is too long, the dynamic chemical potential gradient fluctuation at the phase interface weakens.

[0059] Example 3: In this example, a tubing machining tool with a tungsten-cobalt cemented carbide substrate and a surface coating of aluminum titanium nitride with a thickness of 2μm to 5μm was selected. The mass percentage concentration of unsaturated additives in the main stream of the cleaning fluid was tested in a gradient manner to determine the value boundary from 0.5% to 1.2%. An infrared spectrophotometer with a concentration resolution of 0.01% and a dynamic viscometer with a measurement range of 0.5 mPa·s to 50 Pa·s and a resolution of 0.05 mPa·s were integrated into the sealed cleaning chamber of the flow system test bench. The control unit for multi-flow-path timing switching drives the valve group through a timing state machine to gradually increase the mass percentage concentration of unsaturated additives from 0.4% to 1.3% in 0.1% increments, thus preparing independent liquid cleaning medium sample groups.

[0060] During the test, the total flow rate of the fluid system channel was maintained at 3.15 L / min, the coarse washing pressure was maintained at 3.5 MPa, the injection temperature was maintained at 52℃, and the frequency of the linear sweep frequency megasonic field was linearly swept within the range of 0.8 MHz to 1.2 MHz. Each group of liquid cleaning medium samples flowed into the fluid system channel holding the oil casing machining tool in the center of the axis. The temperature sensor collected the local temperature rise data deep in the crack of the hard coating at a sampling frequency of 10 Hz. The piezoelectric thin film sensor measured the hydrostatic wedge stress generated in the mechanical pinning dead angle when the nano-sized microemulsion droplets were in situ precipitated.

[0061] When the mass percentage concentration of unsaturated additives is less than 0.5%, even if the local temperature deep within the cracks of the hard coating reaches the cloud point threshold of 45°C, sufficient nano-sized microemulsion droplets cannot be precipitated in situ due to insufficient density of active molecular groups. At this time, the hydrostatic wedge stress formed in the coating gaps is less than 0.05 MPa, which cannot break the capillary binding force of the cured oil film layer on the fine alloy debris, and the residual oil film thickness in the mass transfer blind zone is insufficient. When the flow path is kept above 8.5 μm, the mass transfer path inside the flow channel is blocked.

[0062] When the mass percentage concentration of unsaturated additives exceeds 1.2%, excessive polymer segments aggregate and gel in the cleaning solution, causing the bulk dynamic viscosity of the cleaning medium to transiently rise to over 55 mPa·s. As the cleaning solution approaches the deep wall of the chip removal tank, the mass transfer resistance increases accordingly. The hydrodynamic displacement rate between the low dielectric constant nonpolar swelling fluid and the high dielectric constant polar driving fluid decreases, and the composite contaminants in the mass transfer blind zone deep in the chip removal tank remain in their original positions, causing the cleaning process to tend to saturate.

[0063] When the mass percentage concentration of the unsaturated additive is 0.8%, the initial cured oil film thickness is... When the particle size is 15 μm, the average particle size of the in-situ precipitated nano-sized microemulsion droplets is 95 nm. The hydrostatic wedge stress generated within the mechanical pinning dead zone reaches 0.38 MPa. This, combined with the anisotropic microjets generated by cavitation bubble rupture, allows for the acquisition of real-time residual images of the tool surface during oil casing machining using an optical microscopic imaging sensor. These real-time residual images are then compared with a calibrated clean surface reference image within a digital signal processor to measure the image overlap. The desorption rate was 99.3%; the alloy debris desorption rate was determined by the mass difference weighing method. With a success rate of 98.2%, after cleaning, the propagation of fine cracks inside the hard coating under cutting conditions was suppressed, and the source of stress concentration caused by metal chip deposition in the chip groove cutting edge area was removed.

[0064] When the local temperature rise caused by the linear sweep frequency megasonic field reaches the cloud point threshold, the unsaturated additive undergoes phase inversion in the mainstream cleaning fluid, spontaneously condensing and precipitating high-density nanoscale microemulsion droplets in situ. The space deep within the chip removal groove and within the coating gaps is restricted. Under capillary force, the precipitated nanoscale microemulsion droplets enter the contact dead angle between the fine alloy debris and the coating gaps, accumulating there. The pressure pulsation disturbance superimposed in the mainstream cleaning fluid and the anisotropic microjets generated by cavitation bubble rupture propel the accumulated nanoscale microemulsion droplets towards the confined slit. The surrounding hard solid wall forms a boundary constraint on the droplets, transforming the repulsive accumulation effect between droplets into momentum transfer and energy accumulation within the contact angle. The hydrostatic wedge formed by volume repulsion and compressive resistance... Force is applied to the surface of fine alloy debris. The nanoscale microemulsion droplets, acting as the physical extrusion carrier, adhere to the characteristic input parameters of an average droplet size of 50nm to 150nm and an unsaturated additive mass percentage concentration of 0.5% to 1.2% in the mainstream cleaning solution. Through the anisotropic microjets generated by the cavitation bubble rupture, the droplet group densely packed in the dead corner of the slit is subjected to high-frequency periodic collision and pushing action. This causes the droplet group within the geometric boundary of the confined slit to undergo volume compression deformation and accumulate volume repulsive force. As a result, a macroscopic normal stress state that loosens the physical constraints is output in a closed loop on the surface of the fine alloy debris, reaching 0.38MPa within the dead corner of mechanical pinning. This cuts off the capillary binding force of the solidified oil film layer on the fine alloy debris, driving the fine alloy debris to detach.

[0065] Example 4: This example combines Figures 1 to 2 A description of the liquid cleaning process for a type of oil casing machining tool, such as... Figure 1 As shown, a cyclic spray coarse wash is first performed to expose the solidified oil film layer. Then, fluid alternating injection is performed to weaken the adhesion through transient temperature difference. During this fluid alternating injection process, the absorbance of the residual liquid is collected by a photoelectric sensor by monitoring the residual liquid. When an abnormal command is output, the external valve control unit performs automatic liquid replacement. After the fluid alternating injection, a swept frequency megasonic wave is applied to drive the debris desorption using micro-jet. Then, isopropanol vapor is introduced to use tension to pull the residual water out. During image acquisition, a real-time residual image is acquired by an optical microscopic imaging sensor. Finally, when the overlap meets the standard, a cleaning completion signal is output to terminate the cleaning process.

[0066] like Figure 2As shown, the coarse cleaning agent is a compound of oligomeric surfactants and organic solvents; the high dielectric constant polar driving fluid is a compound of ethylene glycol monobutyl ether and deionized water; isopropanol vapor generates a continuous liquid film and constructs the Marangoni surface tension gradient during the process; the low dielectric constant nonpolar swelling fluid is a compound of cycloalkanes and isoalkanes; and the linear sweep frequency megasonic field introduces microjets and precipitates nanoscale microemulsion droplets in situ during the process. All the above components and process elements work together to remove the complex contaminants.

[0067] Example 5: The oil casing machining tool is clamped and confined within the sealed cleaning chamber. The gas flow path is connected and a high-purity nitrogen gas flow with adjustable pressure is introduced. The pressure transmitter measures the pressure difference between the inlet and outlet ends of the flow path and records the pressure difference as the initial gas pressure drop difference. The unit is MPa. The control unit drives the flow regulating valve to adjust the injection flow rate of high-purity nitrogen gas, so that it varies within the range of 10L / min to 20L / min. The digital signal processor receives the initial gas pressure drop difference under different injection flow rates, and determines the geometric flow shear coefficient of the deep layer of the chip groove of the oil casing machining tool based on the monotonic response slope of the initial gas pressure drop difference as a function of the injection flow rate.

[0068] As the injection flow rate of high-purity nitrogen gas changes from 10 L / min to 20 L / min, the pressure transmitter continuously collects the initial gas pressure drop difference corresponding to each injection flow rate. The digital signal processor performs linear fitting on the flow rate data and the initial gas pressure drop difference, extracts the monotonic response slope of the initial gas pressure drop difference as a function of the injection flow rate, and presets a dimensionless geometric normalization constant inside the processor. The constant is calibrated based on the known theoretical geometric resistance of the standard flow channel. Multiplying the monotonic response slope by the geometric normalization constant yields the geometric flow shear coefficient, which characterizes the degree of confinement in the deep space of the chip removal groove.

[0069] After determining the geometric flow shear coefficient, the control system fills the sealed cleaning chamber with a medium used to regulate the interfacial viscosity. An acoustic energy sweep radiation source emits an acoustic pulse signal with a frequency of 1 MHz. A high-precision impedance transmitter measures the initial resonant impedance spectrum inside the flow channel. The digital signal processor calculates the initial phase boundary adhesion resistance characteristic value of the solidified oil film layer based on the peak shift of the initial resonant impedance spectrum. The calculation process completely reverses and reverts to a benchmark engineering verification action based on measurable high-frequency piezoelectric resonant frequency scanning. It is bound to the characteristic input parameter of the absolute value of the electrical admittance output by the impedance transmitter under discrete step-frequency scanning from 0.5MHz to 1.5MHz. Its data processing topology directly extracts the discrete frequency deviation of the impedance spectrum peak center frequency shifted from 1.0MHz to 1.1MHz by the resonant frequency acquisition unit. The microprocessor directly uses this frequency deviation as a one-dimensional index pointer to perform addressing and reading operations on 100 sets of one-dimensional lookup tables containing physical calibration pressures pre-stored in non-volatile memory. This directly obtains the equivalent discrete pressure value of shear stress that is monotonically linearly corresponding to the frequency offset depth. A definite physical characteristic pressure state is output in closed loop in digital space, with the unit being MPa.

[0070] Before the solidified oil film is peeled off, the initial resonant impedance spectrum forms an impedance peak at a specific frequency. As low-dielectric-constant nonpolar swelling fluid and high-dielectric-constant polar displacing fluid are alternately injected, the adhesion between the solidified oil film and the tool surface gradually weakens, and the charge distribution of the double layer at the contact interface changes. Consequently, the frequency corresponding to the impedance peak undergoes a monotonically shift. The digital signal processor uses the peak shift as an index to retrieve adjacent calibration data from a pre-stored correspondence matrix. Through linear interpolation, it obtains the value corresponding to the interface micromechanical failure energy, and then calculates the initial phase boundary adhesion resistance characteristic value, which characterizes the minimum normal shear stress required for the desorption of the solidified oil film. .

[0071] The peak shift of the initial resonant impedance spectrum, expressed in Hz, characterizes the changes in the dielectric state and interfacial charge relaxation frequency within the flow channel. The digital signal processor first converts the peak shift into the variation rate of the interfacial dielectric constant using a pre-built dimensionless normalization algorithm. Then, it multiplies the variation rate of the interfacial dielectric constant by the aforementioned geometric flow shear coefficient to obtain a mechanical quantity characterizing the shear failure strength of the weak intermolecular interactions at the contact surface. The processor then multiplies this by a preset mechanical unit conversion constant to convert the calculation result into an initial phase boundary adhesion resistance characteristic value in MPa. .

[0072] When the initial phase boundary adhesion resistance characteristic value When the set limit is exceeded, the control unit increases the heat tracing temperature control setting value during the alternating injection of low dielectric constant non-polar swelling fluid and high dielectric constant polar discharging fluid, so that the injection temperature of low dielectric constant non-polar swelling fluid increases linearly from 50°C to 55°C, thereby reducing the elongation at break of the solidified oil film layer and keeping the cleaning chamber in the set safe working state.

[0073] Example 6: Before the processing begins, isopropanol vapor is introduced into the flow system channel test bench to circulate and flush the inner wall of the test bench, the support fixture, and the inner wall of the test channel, forming a standard clean physical surface. The flow system channel test bench is started and the gas phase flow path is opened. The flow rate of high-purity nitrogen gas is adjusted to 15 L / min. When the initial gas pressure drop difference output by the pressure transmitter is... When the fluctuation amplitude drops below 0.001MPa and remains below 0.001MPa for 300s, the current test flow channel state is determined as the standard reference condition.

[0074] Under standard reference conditions, at least 50 sets of grayscale feature matrices were collected from the surface of the oil casing machining tool in a standard clean state using an optical microscopic imaging sensor. The mean value of gray values ​​at the same coordinate position in each gray feature matrix is ​​calculated, and the resulting mean matrix is ​​used as the reference input data for the calibrated clean surface reference image. This completes the initial pressure reference calibration and optical imaging reference construction of the fluid mass transfer path inside the cleaning chamber, providing a unified comparison reference for the subsequent contamination detection of oil casing processing tools.

[0075] After completing the initial pressure benchmark calibration and optical imaging benchmark construction, the offline trigger sensitivity calibration of the unsaturated additive precipitation process was performed, and the cloud point threshold was determined based on the local temperature rise response of the mainstream cleaning fluid in the closed cleaning chamber. The unit is °C. The temperature control system gradually increases the cleaning fluid temperature from 40 °C to 50 °C in increments of 0.1 °C, and records the hydrostatic wedge stress value measured by the piezoelectric thin film sensor every 10 seconds. The temperature rise rate was obtained based on the temperature changes and hydrostatic wedge stress changes at adjacent recording times. and stress increment And establish a real-time relationship between the two.

[0076] As the temperature gradually increases, the digital signal processor continuously calculates the stress increment. With the rate of temperature rise The slope of the change is recorded, and when the slope reaches a preset abrupt change slope, the corresponding temperature value is recorded and determined as the cloud point threshold. Simultaneously, as a boundary trigger condition for adjusting the energy consumption density of the linear sweep frequency megasonic wave field during subsequent cleaning processes, the calibration process is used to correct the influence of ambient temperature changes on the in-situ precipitation process of nanoscale microemulsion droplets, so that the cleaning control process can adapt to different ambient temperature and humidity conditions.

[0077] The upper limit of the degradation judgment threshold is determined based on the optical response when suspended particles in the discharged residual liquid cause light scattering saturation. When the threshold is higher than the upper limit, the photoelectric sensor’s ability to resolve changes in transmittance decreases. The lower limit is determined based on the inherent optical noise fluctuations generated by fluid flow in the system pipeline. When the threshold is lower than the lower limit, normal optical noise fluctuations will trigger an automatic liquid replacement command.

[0078] Initial phase boundary adhesion resistance eigenvalue The set limit is determined by the maximum non-destructive shear force that the hard coating on the surface of the oil casing machining tool can withstand; when the initial phase boundary adhesion resistance characteristic value When the upper limit is exceeded, further increasing the peeling force will increase the risk of hard coating peeling off. The lower limit of the limit is determined based on the adhesion of the cured oil film layer that can be overcome by convection cleaning without heat tracing.

[0079] The preset abrupt change slope is determined based on the volume expansion rate when the unsaturated additive reaches the cloud point threshold and undergoes phase inversion. When the actual stress increment rate is lower than the abrupt change slope, the density of the in-situ precipitated nano-scale microemulsion droplets is insufficient, and the resulting hydrostatic wedge stress cannot loosen the capillary binding force of the solidified oil film layer on the fine alloy debris.

[0080] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit of this application and the scope of protection of this invention, and all of these forms are within the protection scope of this application.

Claims

1. A liquid cleaning process for oil casing machining tools, characterized in that, Includes the following steps: Step S101: Inject a low dielectric constant nonpolar swelling fluid at a temperature of 50°C to 55°C into the surface of the oil casing machining tool, followed by injecting a high dielectric constant polar displacing fluid at a temperature of 20°C to 25°C. The fluids alternately penetrate the solidified oil film layer on the surface of the oil casing machining tool, and a transient temperature step of 28°C to 32°C is generated in the solidified oil film layer to weaken the adhesion between the solidified oil film layer and the substrate surface of the oil casing machining tool. Step S102: Apply a linear sweep frequency megasonic wave field to the surface of the oil casing machining tool, use continuous frequency conversion acoustic flow to eliminate the acoustic shadow area in the chip removal groove of the oil casing machining tool, and induce local temperature rise in the deep crack of the solidified oil film layer. When the local temperature rise reaches the cloud point threshold of the unsaturated additive, nano-sized microemulsion droplets are precipitated in situ. The nano-sized microemulsion droplets gather towards the fine alloy debris and coating gaps, and the fine alloy debris is desorbed by the micro-jet generated by the rupture of cavitation bubbles. In step S103, isopropanol vapor is introduced into the surface of the oil casing machining tool. The isopropanol vapor undergoes local condensation on the inner wall of the oil casing machining tool to form a continuous liquid film. The surface tension difference between the continuous liquid film and the residual moisture is used to construct a Marangoni surface tension gradient in the longitudinal direction of the flow channel of the oil casing machining tool. The Marangoni surface tension gradient generates a longitudinal driving force to pull the residual moisture towards the outlet of the flow channel and discharge it.

2. The liquid cleaning process for oil casing machining tools according to claim 1, characterized in that, Step S102 includes the following sub-steps: Step S1021, controlling the frequency of the linearly swept megasonic wave field to be linearly swept within the range of 0.8MHz to 1.2MHz, and emitting megasonic waves to the surface of the oil casing machining tool; Step S1022, using the linearly swept megasonic wave field to induce a local temperature rise deep in the crack, and when the local temperature rise reaches the cloud point threshold of 45°C to 50°C, nano-sized microemulsion droplets are precipitated from the unsaturated additive.

3. The liquid cleaning process for oil casing machining tools according to claim 1, characterized in that, Before step S101, the following steps are also included: under the conditions of a coarse cleaning pressure of 2MPa to 5MPa and a coarse cleaning temperature of 40°C to 45°C, a coarse cleaning agent composed of oligomeric surfactants and organic solvents is sprayed cyclically onto the surface of the oil casing machining tool to flush the surface of the oil casing machining tool to expose the cured oil film layer.

4. The liquid cleaning process for oil casing machining tools according to claim 1, characterized in that, The low dielectric constant nonpolar swelling fluid is a mixture of isoalkanes with 10 to 14 carbon atoms and cycloalkanes in a mass ratio of 3:

1. The high dielectric constant polar displacement fluid is a mixture of ethylene glycol monobutyl ether and deionized water in a mass ratio of 1:

4.

5. The liquid cleaning process for oil casing machining tools according to claim 1, characterized in that, The following fluid management steps are also included: Step S501, during the continuous repeated liquid cleaning process, the real-time absorbance value of the residual liquid discharged by the high dielectric constant polar driving fluid is collected by a photoelectric sensor installed in the drain pipe, and an absorbance time series is established according to the number of cleaning cycles; Step S502, the first derivative of the absorbance time series is calculated to obtain the rate parameter of absorbance change with the number of cleaning cycles; Step S503, when the rate parameter of change exceeds the preset deterioration judgment threshold, an automatic liquid replacement command for the high dielectric constant polar driving fluid is output to the external valve control unit.

6. The liquid cleaning process for oil casing machining tools according to claim 1, characterized in that, Step S103 specifically includes the following sub-steps: Step S1031, controlling the flow rate of isopropanol vapor introduced into the oil casing to the surface of the machining tool to be 15L / min to 20L / min, and controlling the temperature of isopropanol vapor to be 82℃ to 85℃; Step S1032, maintaining the temperature of the inner wall surface to be 25℃ to 30℃, so that the temperature difference between the isopropanol vapor and the inner wall surface is maintained at 52℃ to 60℃, forming a continuous liquid film with a thickness of 5μm to 10μm on the inner wall surface.

7. The liquid cleaning process for oil casing machining tools according to claim 1, characterized in that, The oil casing machining tool includes a tool base made of tungsten cobalt cemented carbide, and the surface of the oil casing machining tool is covered with a hard coating; the hard coating material is aluminum titanium nitride or chromium aluminum nitride, and the thickness of the hard coating is 2μm to 5μm.

8. The liquid cleaning process for oil casing machining tools according to claim 1, characterized in that, The unsaturated additive is a compound composed of fatty alcohol polyoxyethylene ether and unsaturated fatty acids. The mass percentage concentration of the unsaturated additive in the cleaning solution is 0.5% to 1.2%. The cloud point threshold is 45℃ to 48℃, and the average particle size of the nano-sized microemulsion droplets is 50nm to 150nm.

9. A liquid cleaning process for oil casing machining tools according to claim 1, characterized in that, After step S103, the following quality inspection steps are also included: using an optical microscopic imaging sensor located above the chip removal groove of the oil casing machining tool to acquire a real-time residual image of the surface of the oil casing machining tool, and comparing the real-time residual image with the calibrated clean surface reference image, and outputting a cleaning completion signal when the image overlap is not less than 98%.

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