Longitudinal-torsional ultrasonic vibration milling machining system capable of being monitored on line in real time and process of longitudinal-torsional ultrasonic vibration milling machining system

Abstract

The invention discloses an online real-time monitoring longitudinal-torsional ultrasonic vibration milling system and a process thereof. The system comprises a milling unit for executing a workpiece cutting function, an ultrasonic vibration module for generating a composite vibration field, a cooling module for implementing cooling and lubricating, and an information acquisition module for acquiring information in real time. The ultrasonic vibration module applies longitudinal-torsional mode composite vibration with controllable parameters, so that the cutter generates composite motion of longitudinal displacement and circumferential torsion, and a pulse type cutting mode with an instantaneous separation effect is formed. And the chip removal efficiency is improved through the periodic empty cutting effect, the cutter service cycle is prolonged, the material removal rate is increased, and the workpiece surface integrity is improved. Dynamic cutting force signals and cutting temperature field distribution in the workpiece machining process are synchronously collected; and after machining is completed, a mapping model of technological parameters and surface integrity is established according to the three-dimensional surface topography characteristics and roughness parameters of the workpiece, and heat-force-topography multi-dimensional online collaborative quantitative analysis is achieved based on the model.

Description

Technical Field

[0001] The present invention relates to the technical field of precision machining, and in particular to an online real-time monitoring longitudinal torsional ultrasonic vibration milling system and a process thereof. Background Art

[0002] In recent years, with the rapid development of my country's aviation industry, many high-performance materials have been widely used in the manufacture of aircraft engine-related structural parts, including single-crystal high-temperature alloys, intermetallic compounds, and various composite materials. These materials have excellent properties such as light weight, high strength, high modulus, high toughness, and high temperature resistance, but they also bring huge challenges to material processing.

[0003] When faced with the above-mentioned difficult-to-process materials, traditional milling often encounters problems such as high cutting force, rapid tool wear, and poor surface quality. To solve these problems, ultrasonic vibration-assisted milling technology has emerged. It significantly reduces cutting force and improves processing efficiency and surface quality by applying high-frequency vibration to the cutting tool. However, existing ultrasonic vibration-assisted milling technologies are mostly limited to vibration in a single direction (such as longitudinal vibration or torsional vibration), and there are certain difficulties in efficient and high-quality processing of complex morphologies. In addition, the existing technology has a relatively simple evaluation system for the surface quality of the processed surface, relying on roughness parameters, ignoring the dynamic thermomechanical coupling effect, and lacking a coordinated analysis of the dynamic thermomechanical effect and the micromorphology.

[0004] Therefore, developing a stable longitudinal-torsional ultrasonic vibration milling system and providing a systematic multi-source data fusion method for surface quality evaluation to improve surface quality and efficiency while reducing costs have become urgent technical challenges. The multi-source data fusion system proposed in this paper achieves the first closed-loop correlation evaluation of dynamic signals from the machining process and static surface topography. Summary of the Invention

[0005] Purpose of the invention: In order to overcome the deficiencies in the above-mentioned prior art, the present invention provides an online real-time monitoring longitudinal torsional ultrasonic vibration milling system and process thereof, which improves the machinability of difficult-to-machine materials and greatly improves the machining surface quality and machining efficiency, thereby reducing machining costs.

[0006] Technical solution: To achieve the above objectives, the present invention provides the following technical solutions:

[0007] A longitudinal-torsional ultrasonic vibration milling system comprises a milling module for cutting a workpiece, an ultrasonic vibration module, a cutting fluid module and a heat / force acquisition module;

[0008] The ultrasonic vibration module is connected to the milling module, and applies regular and controllable longitudinal and torsional ultrasonic vibration to the milling module to form longitudinal and torsional composite resonance milling;

[0009] The milling module includes a spindle box, an ultrasonic tool holder mounted on the spindle box, and a PCD milling cutter mounted on the ultrasonic tool holder; the ultrasonic vibration module includes an ultrasonic generator and a wireless energy transmission system, and the ultrasonic generator is connected to the wireless energy transmission system via a signal line; the ultrasonic generator generates ultrasonic vibration, and combines with the ultrasonic tool holder to form longitudinal and torsional composite resonance milling;

[0010] The workpiece is mounted on a workbench below the PCD milling cutter via a flat-nose pliers;

[0011] A thermocouple probe is inserted into the workpiece, and the thermocouple probe is connected to a data acquisition system via a wire to collect cutting temperature in real time;

[0012] A dynamometer is installed on the workbench, the dynamometer is connected to the flat-nose pliers via bolts, and the dynamometer is connected to the force signal acquisition system to collect cutting force in real time;

[0013] The milling system also includes a cutting fluid module, which includes a nozzle. The nozzle is used to transport cutting fluid between the machining surface and the tool back face to play the role of cooling, lubricating and removing chips.

[0014] An online real-time monitoring longitudinal torsional ultrasonic vibration milling system and process thereof include the following steps:

[0015] Step 1: Install and debug the above-mentioned milling system, clamp the workpiece with a flat-nose vise, and complete the tool setting;

[0016] Step 2: Start the ultrasonic excitation device to form longitudinal-torsional composite ultrasonic vibration milling, adjust the power, frequency and amplitude so that the tool obtains the ultrasonic motion trajectory and put the system on standby until the operation is stable;

[0017] Step 3: Use the PCD milling cutter to perform rough cutting on the workpiece under the preset cutting parameters. During this period, observe whether the cutting temperature and cutting force acquisition system are collecting data normally.

[0018] Step 4: Use the PCD milling cutter to fine-cut the workpiece under the preset cutting parameters, and record the output of the cutting temperature through the cutting temperature acquisition system, and record the output of the cutting force through the cutting force acquisition system;

[0019] Step 5: Close each module, remove the workpiece and clean it with anhydrous ethanol to obtain the finished product;

[0020] Step 6: Use the sensorfar 3D optical measuring instrument to scan the microscopic topography of the processed surface and calculate the surface roughness Sa value to quantify the degree of surface unevenness;

[0021] Step 7: Use electron scanning microscope (SEM) to observe whether there are defects such as cracks and scratches on the processed surface.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) Improve machining efficiency and precision: The ultrasonic vibration module applies a longitudinal-torsional modal composite vibration with controllable parameters, causing the tool to produce a composite motion of longitudinal displacement and circumferential torsion. The periodic air cutting action promotes chip removal efficiency, effectively suppresses the time-averaged value of cutting force / temperature in traditional machining, effectively reduces cutting force, increases material removal rate, reduces tool wear and extends tool service life, while improving machining accuracy and surface quality, and improving workpiece surface integrity.

[0024] (2) Broaden the scope of application: It is suitable for precision processing of a variety of difficult-to-process materials, especially in high-end manufacturing fields such as aerospace, medical equipment, etc.

[0025] (3) Comprehensive evaluation of machining quality: The proposed multi-source data fusion evaluation method comprehensively considers multiple dimensions such as cutting force, cutting temperature, machining surface roughness, and machining surface micromorphology, and dynamically tracks the coupling relationship between cutting force / temperature and surface morphology (Ra value + texture); discovers the process law of "low feed per tooth → low cutting force → sinusoidal texture → low surface roughness", and establishes a mapping model between process parameters and surface integrity; breaks through the limitations of traditional single roughness evaluation and realizes multi-dimensional collaborative quantitative analysis of thermal-mechanical-morphology. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0027] Figure 1 is a schematic diagram of the milling processing system of the present invention;

[0028] Figure 2 This is a schematic diagram of the principle of longitudinal-torsional composite vibration-assisted milling of the present invention;

[0029] Figure 3 is a schematic diagram of a method for evaluating the quality of a machined surface according to the present invention;

[0030] Figure 4 This is a comparison of the texture characteristics of the processed surface of the present invention; (a) conventional milling, (b) longitudinal torsional ultrasonic vibration milling;

[0031] Figure 5 The three-dimensional morphology and roughness comparison of the processed surface of the present invention; (a) is traditional milling, (b) is longitudinal-torsional ultrasonic vibration milling;

[0032] Figure 6 These are comparison diagrams of the microscopic morphology of the processed surfaces of the present invention; (a) is conventional milling, and (b) is longitudinal-torsional ultrasonic vibration milling.

[0033] Figure 7 2 is a comparison diagram of the cutting force signals of the present invention; (a) is the cutting force Fx of traditional milling, and (b) is the cutting force Fx of longitudinal-torsional ultrasonic vibration milling;

[0034] Figure 8 This is a graph showing the cutting force changing with feed per tooth according to the present invention;

[0035] Figure 9 This is a graph showing the change in cutting temperature with feed per tooth according to the present invention;

[0036] Figure 10 This is a graph showing the variation of the machined surface roughness with the feed per tooth of the present invention;

[0037] Numbers in the figure: 1. Spindle box; 2. Wireless energy transmission device; 3. Ultrasonic generator; 4. Ultrasonic tool holder; 5. PCD milling cutter; 6. Dynamometer; 7. Workbench; 8. Nozzle; 9. Workpiece; 10. Flat-nose pliers; 11. Temperature acquisition card; 12. Data acquisition device; 13. Signal amplifier; 14. Computer; 15. Axial vibration direction; 17. Torsional vibration direction; 18. Tool feed direction. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0039] Example 1:

[0040] like Figure 1 As shown, an online real-time monitored longitudinal-torsional ultrasonic vibration milling system includes a milling module, a cooling module, an information acquisition module, and an ultrasonic vibration module for cutting a workpiece 9. The ultrasonic vibration module is connected to the milling module, which includes a spindle box 1, an ultrasonic tool holder 4 mounted on the spindle box 1, and a PCD milling cutter 5 mounted on the ultrasonic tool holder 4. The ultrasonic vibration module includes a wireless energy transmission device 2 and an ultrasonic generator 3. The wireless energy transmission system 2 is mounted on the ultrasonic tool holder 4 and connected to the ultrasonic generator 3 via a signal line. The ultrasonic generator 3 generates ultrasonic waves, and the wireless energy transmission system 2 transmits ultrasonic energy to the ultrasonic tool holder. The ultrasonic tool holder 4 drives the tool to perform longitudinal-torsional composite resonance milling on the workpiece, so that the tool-chip contact area is always in a high stress state, promoting the formation of continuous chips, greatly improving chip breaking and discharge, and thus reducing the friction effect between the tool, the chips, and the workpiece 9. This reduces the cutting force of the milling cutter, lowers the cutting temperature, and greatly improves the cutting effect.

[0041] A workpiece 9 is mounted on a workbench 7 below a PCD milling cutter 5 using a flat-nose pliers 10. A thermocouple probe is inserted into the workpiece 9 and connected via a wire to a temperature acquisition card 11. This temperature acquisition card is connected to a computer 14 to collect real-time cutting temperature data. A dynamometer 6 is mounted on the workbench 7 and connected to the flat-nose pliers 10 via bolts. The dynamometer 6 is then connected to a signal amplifier 12, a data acquisition device 13, and a computer 14 to collect real-time cutting force data.

[0042] In this embodiment, the force signal acquisition system comprises a Kistler 5070 charge amplifier and a Kistler 5697A piezoelectric dynamometer. The machine tool used is a VDL-850A three-axis vertical machining center manufactured by Dalian Machine Tool Co., Ltd. of General Technology Group. The laboratory in which the machine tool is located is controlled at a temperature of 20±0.1°C, a humidity of 35±5%, and a cleanliness level of Class 1000 or higher. Workpiece 9 is a GH4169 test block measuring 40mm×20mm×6mm, with a base material of Ni and reinforcements such as Cr, Mo, and Nb. The tool is a PCD end mill with a length of 38mm, a diameter of 6mm, a rake angle of 5°, a clearance angle of 10°, and a helix angle of 38°.

[0043] The cutting fluid is transported to the workpiece processing surface through the nozzle 8, that is, between the workpiece processed surface and the tool back face, to play the role of cooling, lubricating and removing chips.

[0044] refer to Figure 3 As shown, an online real-time monitored longitudinal torsional ultrasonic vibration milling process includes the following steps:

[0045] Step 1: Ensure that the working characteristics of each axis system of the processing machine tool are normal, start the machine tool to preheat and achieve thermal stability so that it can operate stably, and adjust and maintain the humidity and air cleanliness of the laboratory where the machine tool is located.

[0046] Step 2: Install the wireless energy transmission device 2 on the spindle of the machine tool spindle box 1 and connect it to the ultrasonic generator 3 via a signal cable. After installing the PCD milling cutter 5 on the ultrasonic tool holder 4, install the entire device on the machine tool spindle 1. Install the dynamometer 6 and secure it to the workbench 7 with fastening bolts. Install the workpiece 9 with the clamp 10 and secure the clamp 10 to the dynamometer 6 with bolts. Install the workpiece 9 and tighten it with the clamp 10 to complete the tool setting. Connect the thermocouple wire on the workpiece 9 to the temperature acquisition card 11, and connect the temperature acquisition card 11 to the computer 14. Install and debug the cutting fluid module.

[0047] Step 3: Turn on the power of ultrasonic generator 3, and ultrasonic tool holder 4 outputs ultrasonic waves to form longitudinal torsional composite resonance milling. Figure 2As shown, the composite resonance milling includes an axial vibration direction 15, a torsional vibration direction 17 and a tool feed direction 18. The frequency, power and other parameters of the ultrasonic generator are adjusted so that the tool obtains the desired ultrasonic amplitude and ultrasonic motion trajectory and the system is put into standby mode until the operation is stable.

[0048] The frequency and amplitude of the longitudinal-torsional ultrasonic vibration cutting device can be adjusted by adjusting the ultrasonic power excitation device and the spiral groove of the ultrasonic tool handle (transducer and amplitude transformer); the simple harmonic frequency of the composite ultrasonic vibration cutting is controlled at around 25kHz; the output longitudinal amplitude is 4μm and the torsional amplitude is 2μm.

[0049] Step 4: Use the PCD milling cutter 5 to perform rough cutting on the workpiece 9 under the preset cutting parameters, and observe whether the cutting temperature and cutting force acquisition system are collecting data normally during this period; use the PCD milling cutter 5 to perform fine cutting on the workpiece 9 under the preset cutting parameters, and record the output of the cutting temperature through the cutting temperature acquisition system, and record the output of the cutting force through the cutting force acquisition system.

[0050] In this embodiment, the rough cutting parameters are ap = 10 mm, ae = 0.5 mm, f = 0.1 mm / z, and n = 3714 rpm. The fine cutting parameters are ap = 6 mm, ae = 0.2 mm, f = 0.01-0.05 mm / z, and n = 1592 rpm, where ap is the cutting depth, ae is the cutting width, f is the feed per tooth, and n is the spindle speed.

[0051] Step 5: Shut down all devices and components, remove the test workpiece 9 and clean it with anhydrous ethanol, evaluate the surface quality, and perform digital reconstruction of the three-dimensional morphology.

[0052] (1) Using the sensorfar three-dimensional optical measuring instrument, the microscopic topography of the machined surface is scanned and the surface roughness Ra value is calculated to quantify the degree of surface unevenness; the results are referenced to Figure 4 、 Figure 5 shown. Figure 4 In the figure, (a) is traditional milling, and (b) is longitudinal-torsional ultrasonic vibration milling. It can be seen from the figure that the surface texture of the traditional milling process appears fish scale-like, and the surface texture of the longitudinal-torsional ultrasonic vibration milling process appears sinusoidal texture. Figure 5 (a) is traditional milling, and (b) is longitudinal-torsional ultrasonic vibration milling. It can be seen from the figure that the surface roughness Ra of longitudinal-torsional ultrasonic vibration milling is significantly lower than that of traditional milling.

[0053] (2) Use electron scanning microscope (SEM) to observe whether there are defects such as cracks and scratches on the processed surface. Figure 6As shown in the figure, (a) is traditional milling, and (b) is longitudinal torsional ultrasonic vibration milling. It can be observed from the figure that there are grooves, scratches, voids and material adhesion on the surface processed by traditional milling, and there are uniform sinusoidal textures and fragments on the surface processed by longitudinal torsional ultrasonic vibration milling. The surface processed by longitudinal torsional ultrasonic vibration milling is obviously better than conventional milling.

[0054] (3) Figure 7 The comparison diagram of cutting force signal amplification is shown in Figure 1, where (a) is the cutting force Fx of traditional milling and (b) is the cutting force Fx of longitudinal-torsional ultrasonic vibration milling. Figure 7 It can be seen that the output peak value of the cutting force Fx of longitudinal-torsional ultrasonic vibration milling is significantly lower than the peak value of the cutting force Fx of traditional milling.

[0055] (4) Comparison of the effect of feed per tooth on the cutting force of longitudinal-torsional ultrasonic vibration milling. Figure 8 It can be seen that with the increase of feed per tooth, the cutting forces Fx and Fy of longitudinal-torsional ultrasonic vibration milling and conventional milling both increase, but the cutting forces Fx and Fy of longitudinal-torsional ultrasonic vibration milling are always lower than those of conventional milling.

[0056] (5) Comparison of the effect of feed per tooth on cutting temperature in longitudinal-torsional ultrasonic vibration milling. Figure 9 It can be seen that with the increase of feed per tooth, the cutting temperature of both longitudinal and torsional ultrasonic vibration milling and conventional milling increases, but the cutting temperature of longitudinal and torsional ultrasonic vibration milling is always lower than that of conventional milling.

[0057] (6) The effects of feed per tooth parameters on the surface roughness of the machined surface were compared. The results are as follows: Figure 10 , it can be obtained that the surface roughness increases with the increase of feed per tooth, and the surface roughness of longitudinal-torsional ultrasonic vibration milling is lower than that of conventional milling under the same parameters.

[0058] Step 6: Based on the information obtained in step 5 and the data acquired in real time in step 4, a three-dimensional correlation model is established, which specifically includes the construction and derivation of the following models: longitudinal and torsional vibration kinematic model, cutting force model, cutting temperature model, surface roughness model, and derivation of the three-parameter mapping relationship.

[0059] (1) Longitudinal-torsional vibration kinematic model

[0060] z(t)=A l sin(2πft) (1)

[0061]

[0062] Among them, z(t) is the longitudinal displacement, θ(t) is the torsional displacement, and A l is the longitudinal amplitude, A tis the torsional amplitude, f is the vibration frequency, v is the tangential velocity, ω c is the spindle angular velocity, ω t is the torsion angular velocity, R is the tool radius, is the phase difference, and t is the time.

[0063] (2) Cutting force model

[0064] dF t =[K tc (T)·h(t)+K te ]db (4)

[0065] K tc (T) = K tc0 ·e -βT (5)

[0066] h(t)=max(f z sinθ+z(t)+R·θ(t),0) (6)

[0067] Among them, dF t is the microelement tangential cutting force, T is the temperature, h(t) is the instantaneous undeformed chip thickness (modulated by vibration, tool-workpiece separation occurs when h(t) = 0), db is the microelement cutting width, K te is the cutting edge coefficient, K tc0 is the temperature coefficient, β is the material temperature softening coefficient, f z is the feed per tooth.

[0068] (3) Cutting temperature model

[0069] The temperature field is dominated by plastic deformation work and friction work. Vibration changes the temporal and spatial distribution of the heat source. The heat source intensity model is shown in Equation (7), where is the heat generation rate per unit volume, η is the heat distribution coefficient, τ is the shear stress, is the shear strain rate, μ is the friction coefficient, p is the contact pressure, v r is the relative sliding speed.

[0070]

[0071] The effects of vibration on heat sources include separation effect: the tool cools down when it is separated, reducing the average temperature, and concentration effect: high-speed impact increases the instantaneous heat flux density. The transient temperature control equations are shown in Equations (8) and (9), where ρ is the material density, c p is the specific heat capacity at constant pressure, k is the thermal conductivity, and δ(t) characterizes the indirect heating caused by vibration.

[0072]

[0073] The average temperature approximate solution is as shown in equation (10), where T0 is room temperature, v c is the cutting speed, is the average cutting power α is the thermal diffusion coefficient, a e is the cutting width, a p is the axial cutting depth.

[0074]

[0075] (4) Surface roughness model:

[0076] The surface morphology is affected by the geometric motion trajectory, thermal deformation and vibration response. Equations (11) and (12) are the surface roughness corrected by the geometric residual height, where λ is the tool-workpiece contact length. Equation (13) is the surface roughness caused by lateral plastic flow due to high temperature softening of the material, where k m is the material flow coefficient, T max is the maximum temperature, T g is the softening transition temperature of the material.

[0077]

[0078] (5) Derivation of three-parameter mapping relationship

[0079] The mapping relationship between cutting force and cutting temperature is shown in formula (14).

[0080]

[0081] The mapping relationship between cutting temperature and surface roughness is shown in formula (15).

[0082]

[0083] Combining the geometric, mechanical, and thermal contributions, the complete mapping equation is obtained as shown in Equation (16).

[0084]

[0085] where K g is the geometric residual coefficient, K v is the vibration trajectory amplitude coefficient, K f is the cutting force-separation effect coefficient, K T is the thermoplastic coefficient and can be calibrated through experiments.

[0086] In this embodiment, combined Figure 8 、 Figure 9 and Figure 10 , bring the data into the three-dimensional correlation model and obtain K g is 5.043, K v is 16166.5, Kf is 0.0645, K T =-1.114×10 -9 , it can be obtained that when the cutting force Fx decreases by 10N, the surface roughness Ra value decreases by 15%-18%.

[0087] Step 7: Based on the quantitative law established in step 6, during the longitudinal-torsional ultrasonic vibration cutting process, the surface quality indicators of the workpiece during the processing are monitored online through real-time monitoring of the cutting force.

[0088] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An online real-time monitoring longitudinal and torsional ultrasonic vibration milling system, characterized in that: It includes a milling module, an ultrasonic vibration module, a cooling module and an information acquisition module for milling a workpiece; the ultrasonic vibration module is connected to the milling module, and a longitudinal-torsional modal composite vibration with controllable parameters is applied by the ultrasonic vibration unit to cause the tool to produce a composite motion of longitudinal displacement and circumferential torsion, forming a pulsed cutting mode with an instantaneous separation effect, so that the contact area of ​​the tool and the chip is always in a high stress state; the information acquisition module is set on the workpiece and the workbench, collects the cutting temperature and cutting force in real time, and transmits the information to the data acquisition system; the coolant nozzle of the cooling module delivers cutting fluid to the workpiece processing surface to continuously cool it down.

2. The online real-time monitoring longitudinal and torsional ultrasonic vibration milling system according to claim 1 is characterized in that: The ultrasonic vibration module is connected to the milling module. The milling module includes a spindle box, an ultrasonic tool holder is installed on the spindle box, and a milling cutter is installed on the ultrasonic tool holder. A thermocouple probe is inserted into the workpiece, and the thermocouple probe is connected to a temperature acquisition card through a wire. The temperature acquisition card is connected to a computer to collect cutting temperature in real time. A dynamometer is installed on the workbench, and the dynamometer is connected to a flat-nose pliers through a bolt. The dynamometer is connected to a signal amplifier, a data acquisition instrument and a computer to collect cutting force in real time.

3. The online real-time monitoring longitudinal and torsional ultrasonic vibration milling system according to claim 1 is characterized in that: The ultrasonic vibration module includes an ultrasonic generator and a wireless energy transmission system. The wireless energy transmission system is installed in the ultrasonic tool handle, and the ultrasonic generator is connected to the wireless energy transmission system through a signal line. The ultrasonic generator generates ultrasonic vibration and combines with the ultrasonic tool handle to form longitudinal and torsional ultrasonic vibration milling.

4. An online real-time monitored longitudinal torsional ultrasonic vibration milling process based on the online real-time monitored longitudinal torsional ultrasonic vibration milling system according to claim 1, characterized in that: Here are the steps: (1) The ultrasonic vibration module applies a longitudinal-torsional composite vibration with controllable parameters to the workpiece on the workbench, and the tool generates a composite motion of longitudinal displacement and circumferential torsion, forming a pulsed cutting mode with an instantaneous separation effect, so that the tool-chip contact area is always in a high stress state; (2) The coolant nozzle of the cooling module continuously delivers cutting fluid to the workpiece processing surface to continuously reduce the temperature; (3) The thermocouple probe on the workpiece collects the cutting temperature in real time; the dynamometer installed on the workbench collects the cutting force in real time. The information collected by both is transmitted to the data acquisition system and integrated and processed; (4) Scan the microscopic topography of the finished workpiece surface, calculate the surface roughness Ra value, and quantify the degree of surface unevenness; Observe defects such as cracks and scratches on the processed surface; (6) establishing a mapping model between process parameters and surface integrity based on the data collected in real time in step (3) and the morphological features collected in step (4); (7) Based on the three-dimensional correlation model of cutting force, cutting temperature and roughness Ra value established in step (6), a multi-dimensional collaborative online quantitative analysis of heat, force and morphology is realized, and online real-time monitoring is achieved.

5. The online real-time monitored longitudinal-torsional ultrasonic vibration milling process according to claim 4 is characterized in that: In step (3), the cutting force and cutting temperature are correlated with the feed per tooth to obtain the influence of the single factor of feed per tooth on the cutting force and temperature of longitudinal-torsional ultrasonic vibration milling.

6. The online real-time monitored longitudinal-torsional ultrasonic vibration milling process according to claim 4 is characterized in that: Step (6) establishes a three-dimensional correlation model by correlating and analyzing the cutting force, cutting temperature, and roughness Ra value. The modeling process is as follows: (1) Longitudinal-torsional vibration kinematic model z(t)=A l sin(2πft) (1) Among them, z(t) is the longitudinal displacement, θ(t) is the torsional displacement, and A l is the longitudinal amplitude, A t is the torsional amplitude, f is the vibration frequency, v is the tangential velocity, ω c is the spindle angular velocity, ω t is the torsion angular velocity, R is the tool radius, is the phase difference, t is the time; (2) Cutting force model dF t =[K tc (T)·h(t)+K te ]db (4) K tc (T)=K tc0 ·e -βT (5) h(t)=max(f z sinθ+z(t)+R·θ(t),0) (6) Among them, dF t is the microelement tangential cutting force, T is the temperature, h(t) is the instantaneous undeformed chip thickness (modulated by vibration, tool-workpiece separation occurs when h(t) = 0), db is the microelement cutting width, K te is the cutting edge coefficient, K tc0 is the temperature coefficient, β is the material temperature softening coefficient, f z is the feed per tooth; (3) Cutting temperature model The temperature field is dominated by plastic deformation work and friction work. Vibration changes the temporal and spatial distribution of the heat source. The heat source intensity model is shown in Equation (7), where is the heat generation rate per unit volume, η is the heat distribution coefficient, τ is the shear stress, is the shear strain rate, μ is the friction coefficient, p is the contact pressure, v r is the relative sliding velocity; The influence of vibration on heat source includes separation effect: the tool cools down when it is separated, reducing the average temperature, and concentration effect: high-speed impact increases the instantaneous heat flux density. The transient temperature control equations are shown in Equations (8) and (9), where ρ is the material density, c p is the specific heat capacity at constant pressure, k is the thermal conductivity, and δ(t) characterizes the indirect heating caused by vibration; The approximate solution of the average temperature is as shown in Equation (10), where T0 is room temperature, v c is the cutting speed, is the average cutting power d is the thermal diffusion coefficient, a e is the cutting width, a p is the axial cutting depth; (4) Surface roughness model: The surface morphology is affected by the geometric motion trajectory, thermal deformation and vibration response. Equations (11) and (12) are the surface roughness corrected by the geometric residual height, where λ is the tool-workpiece contact length; Equation (13) is the surface roughness caused by the lateral plastic flow caused by the high temperature softening of the material, where k m is the material flow coefficient, T max is the maximum temperature, T g is the softening transition temperature of the material; (5) Derivation of three-parameter mapping relationship The mapping relationship between cutting force and cutting temperature is shown in formula (14); The mapping relationship between cutting temperature and surface roughness is shown in formula (15); Combining the geometric, mechanical, and thermal contributions, the complete mapping equation is obtained as shown in Equation (16); where K g is the geometric residual coefficient, K v is the vibration trajectory amplitude coefficient, K f is the cutting force-separation effect coefficient, K T is the thermoplastic coefficient and can be calibrated through experiments.

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