CN-121973019-A - Supercritical CO for variable working condition processing2Micro-lubrication nozzle selection regulation and control method and device

Abstract

The invention discloses a method and a device for selecting and regulating a supercritical CO 2 micro-lubrication nozzle for variable working condition processing. The method comprises the steps of calculating theoretical gas cooling temperature difference under corresponding machining conditions based on working condition parameters of current cutting machining, calculating average heat flux density required by cooling a cutting area to a target area, calculating total heat required by jet flow to be absorbed from the cutting area, calculating an outlet area or caliber range of a target nozzle, selecting matched nozzles from a preset nozzle library according to the outlet area or caliber range, and selecting a nozzle with caliber closest to the central value of the range if a plurality of nozzles meet the conditions. According to the invention, through continuously reading the cutting machining parameters of the machining equipment and the cooling requirements of the machined metal, the caliber of the optimal cooling and lubricating nozzle in the machining state is predicted, the proper cooling and lubricating nozzle is rapidly selected and switched, the nozzle is accurately positioned to the cutting area, and the dynamic switching of the cooling and spraying mode according to the machining conditions is realized.

Inventors

• ZHU LIBIN
• ZHAO XU
• CHEN GUANYU
• Bi Jiehai

Assignees

• 合肥工业大学

Dates

Publication Date

20260505

Application Date

20260126

Claims (10)

1. 1. A method for selectively regulating and controlling a supercritical CO 2 micro-lubrication nozzle for variable working condition machining is characterized by comprising the following steps: S1, calculating a theoretical gas cooling temperature difference under corresponding machining conditions through a cutting temperature prediction model based on working condition parameters of current cutting machining; S2, calculating the average heat flux density required by cooling the cutting area to a target area based on the cooling temperature difference, the thermophysical parameters of the processed material and the heat source distribution characteristics of the cutting area caused by different cutting parameters; S3, calculating total heat required to be absorbed by jet flow from the cutting area based on the heat flow density and the effective action area of the CO 2 jet flow impinging on the cutting wall surface; S4, calculating the outlet area or caliber range meeting the target nozzle based on the supply pressure and temperature of the CO 2 and combining the total heat and the jet pressure and temperature of the CO 2 supply side; and S5, selecting matched nozzles from a preset nozzle library according to the outlet area or the caliber range, and selecting a nozzle with the caliber closest to the central value of the range if a plurality of nozzles meet the conditions.
2. 2. The method for selectively controlling supercritical CO 2 minimal quantity lubrication nozzles for variable-working-condition processing according to claim 1, wherein in step S1, said working-condition parameters include cutting speed Feed amount of cutter Cutting depth and processed material density Thermal conductivity Tool geometry and ambient temperature during the current machining process The expression of the prediction model is as follows: ; In the formula, Indicating the difference in the cooling temperature of the cooling medium, Indicating the target cooling temperature of the cooling medium, Representing the coefficient of thermal distribution, Representing the main cutting force of the material during the dry cutting process, Representing depth of cut, the tool geometry parameters including tool rake angle Angle of shear Tool principal angle 。
3. 3. The method for selectively controlling the supercritical CO 2 micro-lubrication nozzle for variable-working-condition machining according to claim 2, wherein in step S2, the calculation formula of the average heat flow density is as follows: ; In the formula, Representing the heat flux density of CO 2 at the rake face, Indicating that the CO 2 jet actually covers the tool surface area, Indicating the width of the tool and, 、 Representing the abscissa and ordinate.
4. 4. The method for selectively controlling the supercritical CO 2 micro-lubrication nozzle for variable-working-condition machining according to claim 3, wherein in step S3, the calculation formula of the total heat is: ; In the formula, Which is indicative of the total heat quantity in question, Representing the radius of the jet of CO 2 injected onto the surface of the cutting region, Representing the compensation coefficient.
5. 5. The method for selectively controlling a supercritical CO 2 minimal quantity lubrication nozzle for variable-working-condition machining according to claim 4, wherein in step S4, a caliber is selected and calculated from the caliber range, and a calculation formula is: ; In the formula, The diameter of the pipe is indicated as such, The flow rate is indicated by the flow rate, The flow coefficient is represented by a value representing, The pressure of the standard state is indicated, Represents the specific heat capacity of CO 2 , The gas constant is represented by a value of, Represents the specific heat ratio of CO 2 , The temperature of the atmosphere is indicated, Representing the temperature parameter of the high pressure CO 2 provided by the CO 2 supply, Indicating the specific enthalpy of the CO 2 jet entering the cutting zone.
6. 6. The method for selectively controlling the supercritical CO 2 micro-lubrication nozzle for variable-working-condition machining according to claim 1, wherein the method for controlling the supercritical CO 2 micro-lubrication nozzle further comprises the following steps: S6, monitoring the actual temperature of a cutting area in real time in the cutting process; And S7, if the number of times that the actual temperature exceeds a preset target processing temperature interval reaches a threshold value in a set time period, updating the prediction model and the calculation parameters according to real-time monitoring data, and re-executing the steps S1 to S5 to dynamically correct and select a new target nozzle for switching.
7. 7. The method for selectively controlling the supercritical CO 2 micro-lubrication nozzle for variable working condition processing according to claim 6, wherein the target processing temperature interval is an ideal processing temperature based on a processed material or a temperature interval preset according to a processing technology requirement.
8. 8. A supercritical CO 2 micro-lubrication nozzle selection control device for variable working condition processing, characterized in that it applies the supercritical CO 2 micro-lubrication nozzle selection control method for variable working condition processing according to any one of claims 1 to 7, the device comprising: The data acquisition module is used for acquiring cutting working condition parameters, CO 2 supply pressure and temperature and real-time temperature of a cutting area; the calculation and control module is connected with the data acquisition module and used for executing the calculation step in the method based on the acquired data and generating a nozzle selection and switching instruction; The nozzle execution module is connected with the calculation and control module and comprises a plurality of nozzles with different calibers, a driving mechanism for driving the nozzles to move to a working position or retract, and a valve for controlling the on-off of fluid of each nozzle.
9. 9. The method for selectively regulating and controlling the supercritical CO 2 micro-lubrication nozzle for variable working condition machining according to claim 8, wherein the data acquisition module comprises a thermal infrared imager for monitoring the temperature of a cutting area and a pressure and temperature transmitter for monitoring the pressure and temperature of a CO 2 supply pipeline, the driving mechanism in the nozzle execution module is a cylinder, and the valve is an electric switch valve.
10. 10. The variable regime process supercritical CO 2 trace lubrication nozzle selection conditioning apparatus of claim 8, further comprising a two-dimensional positioning slide for mounting the nozzle execution module and adjusting its position relative to the cutting zone.

Description

Supercritical CO 2 micro-lubrication nozzle selection regulation and control method and device for variable working condition machining Technical Field The invention relates to a nozzle selection regulation method in the technical field of machining and manufacturing, in particular to a supercritical CO 2 micro-lubrication nozzle selection regulation method for variable working condition machining, and also relates to a supercritical CO 2 micro-lubrication nozzle selection regulation device for variable working condition machining. Background With the increasing demands for high-performance materials in the high-end manufacturing fields of aerospace, energy equipment and the like, metal cutting processing faces serious challenges such as high cutting temperature, rapid cutter abrasion and the like. The cooling and lubricating technology is important to control the processing quality and improve the efficiency. In particular, supercritical CO 2 micro lubrication technology is attracting attention due to its excellent cooling and environmental protection properties. However, in actual production, a workpiece often needs to undergo a plurality of processing steps continuously, and its cutting parameters (such as speed, feed, cutting depth) dynamically change from process to process, resulting in a change in the thermal load of the cutting zone. The ideal cooling and lubricating effect is highly sensitive to the selection of nozzle caliber and jet flow parameters, and a single cooling scheme is difficult to adapt to the processing requirement of the variable working condition. In the prior art, the selection and switching of the nozzles mainly depend on manual experience. Not only is this inefficient, but it often requires a shut down operation to interrupt the production flow. In the switching process, if the high-pressure residual air in the pipeline cannot be safely released, the potential safety hazard of hurting people due to splashing of the nozzle exists. Furthermore, most processing equipment is equipped with only a single fixed nozzle, which has limited cooling capacity and cannot be adaptively adjusted. To cope with different heat loads, operators tend to simply and inefficiently increase the CO 2 supply pressure, which not only results in little increase in cooling effect after reaching a threshold, resulting in a huge waste of energy and resources, but also easily results in long time high load operation of the equipment. More importantly, the single cooling condition cannot be accurately matched with the changed working condition, and severe temperature fluctuation of a cutting area is extremely easy to cause. Once the temperature exceeds the proper range of material processing, a series of process problems such as accelerated tool wear, reduced processing precision and the like are directly caused. Therefore, there is a need for an intelligent control method and device capable of automatically selecting and switching the optimal nozzles according to the real-time conditions. Disclosure of Invention The invention provides a method and a device for selectively regulating and controlling a supercritical CO 2 micro-lubrication nozzle in variable working condition processing, aiming at solving the technical problems of low efficiency and single cooling effect of the existing intelligent regulating and controlling method and device for the nozzle. The invention adopts the following technical scheme that the method for selectively regulating and controlling the supercritical CO 2 micro-lubrication nozzle in variable working condition processing comprises the following steps: S1, calculating a theoretical gas cooling temperature difference under corresponding machining conditions through a cutting temperature prediction model based on working condition parameters of current cutting machining; S2, calculating the average heat flux density required by cooling the cutting area to a target area based on the cooling temperature difference, the thermophysical parameters of the processed material and the heat source distribution characteristics of the cutting area caused by different cutting parameters; S3, calculating total heat required to be absorbed by jet flow from the cutting area based on the heat flow density and the effective action area of the CO 2 jet flow impinging on the cutting wall surface; S4, calculating the outlet area or caliber range meeting the target nozzle based on the supply pressure and temperature of the CO 2 and combining the total heat and the jet pressure and temperature of the CO 2 supply side; and S5, selecting matched nozzles from a preset nozzle library according to the outlet area or the caliber range, and selecting a nozzle with the caliber closest to the central value of the range if a plurality of nozzles meet the conditions. According to the invention, the cutting parameters of the processing equipment and the cooling requirements of the processed metal are continuously read