A device and method for ultrasonic turning and milling precision machining of high-performance threads

Abstract

A device and a method for using ultrasonic milling to precisely process high-performance threads. The present invention discloses a device for precisely processing high-performance threads by ultrasonic milling, comprising a tool fixing workbench, a composite pre-tightening layer arranged on one side of the tool fixing workbench, and a pressure plate shell fixedly connected to the composite pre-tightening layer. A connecting member I is provided in the middle of the pressure plate shell, a connecting member II is provided on the upper part, and a floating support plate is provided at the lower part. A fixing member is provided in the middle of connecting member I and connecting member II. The lower side surface of the fixing member is fixedly connected to connecting member I, and the middle side surface is connected to connecting member II. A bottom supporting member is provided at the bottom of the fixing member, a motor is provided on the bottom supporting member, a coupling is provided on the output shaft of the motor, a tool rod is provided on the coupling, a tool disc is provided on the tool rod, and a piezoelectric actuator is provided on the outer surface of the tool rod; the present invention discloses a method for using the device for precisely processing high-performance threads by ultrasonic milling, which can process pipes with performance threads to be processed and improve processing efficiency, workpiece quality and tool life.

Description

Technical Field

[0001] The present invention relates to the field of machining, and in particular to a device and a method for using the ultrasonic turning and milling method for precisely machining high-performance threads. Background Art

[0002] With the continuous development of science and technology, the performance requirements of components are becoming increasingly higher, and materials with higher strength and hardness are constantly being developed. These materials not only have large unit force and heat coefficients and large fluctuation amplitudes during processing, but also have high stress sensitivity coefficients. That is, sudden concentration of stress can significantly reduce their performance. This places higher demands on processing equipment and their use methods. The material for high-performance threads is a new generation of gear steel with a yield strength exceeding 1700MPa and a hardness exceeding 63HRC. Ultrasonic vibration can significantly reduce cutting forces and heat under appropriate working conditions, thereby improving tool life and workpiece quality. The patented invention provides a device and processing method for the combined turning and milling of high-performance threads under ultrasonic vibration, which can be installed and used on ordinary lathes, thereby improving processing efficiency, workpiece quality and tool life. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a device and a method for using ultrasonic turning and milling to precisely process high-performance threads.

[0004] The technical solution adopted by the present invention to solve the technical problem is:

[0005] A device for ultrasonic turning and milling precision machining of high-performance threads, comprising a tool fixing workbench, a composite pre-tightening layer arranged on one side of the tool fixing workbench, and a pressure plate shell fixedly connected to the composite prefabricated layer, wherein a connecting member I is provided in the middle portion of the pressure plate shell, a connecting member II is provided in the upper portion, and a floating support plate is provided in the lower portion, a fixing member is provided in the middle portion of the connecting member I and the connecting member II, a lower side surface of the fixing member is fixedly connected to the connecting member I, and a middle side surface is connected to the connecting member II, a bottom support member is provided at the bottom of the fixing member, a motor is provided on the bottom support member, a coupling is provided on the output shaft of the motor, a tool rod is provided on the coupling, and a cutter disc is provided on the tool rod, wherein a piezoelectric actuator is provided on the outer surface of the tool rod;

[0006] The motor is fixedly connected to the fixing member through fixing member I and fixing member II, wherein the connection between the fixing member I and the motor is the vibration mode of the motor; the connection between the fixing member II and the fixing member is the node of the vibration mode of the fixing member.

[0007] In one embodiment, the inner side of the pressure plate shell is hexagonal, the connector I and the connector II are both hexagonal connectors, and the fixing member is hexagonal.

[0008] In one embodiment, a first connecting member and a second connecting member are provided at the upper and lower ends of the piezoelectric actuator and on the outside of the knife rod, the inner and outer sides of the first connecting member and the second connecting member are both hexagonal, the inner sides of the first connecting member and the second connecting member are connected to the knife rod through rolling bearings, and the outer sides are fixedly connected to the fixing member, wherein the connection between the first connecting member and the second connecting member and the knife rod is the node of the knife rod's excitation vibration mode of the piezoelectric actuator.

[0009] In one embodiment, the cutter disc has a diameter of 4-6 mm and is provided with cutting tools, wherein the cutter disc (3) can be equipped with a plurality of cutting tools, and the front and rear surfaces of the cutting tools are provided with a composite coating and form a first layer of TiN, a second layer of TiAlN, and a third layer of TiN.

[0010] In one embodiment, the tool has a front angle ≤5° and a back angle ≥15°; a groove is provided on the back face of the tool, the end of the groove is 4 μm away from the cutting edge, the depth of the groove is 2 μm-8 μm and the width is 1 μm when extended linearly outward from the cutting edge, and the plurality of grooves are arranged like veins in leaves.

[0011] In one embodiment, the front cutting edge of the tool is provided with a restrictive contact groove, which is located at 1um, 4um, and 6um away from the cutting edge, with a width of 1.5um and a depth of 2um; a chip breaker groove with a width of 3mm and parallel to the cutting edge is opened at 10um away from the cutting edge, and the distal face of the chip breaker groove is 1mm higher than the proximal face, and the proximal face refers to the side close to the cutting edge; the front cutting edge angle is 1°-2°; the back angle of the tool is 10°-20°, and vein-shaped grooves are added to the front cutting edge, with a spacing of 8-10um between the partings, a groove width of 1.5-3um, a groove direction of 25° to the cutting edge, and a distance of 2-4um from the cutting edge. When the groove depth extends linearly outward from the cutting edge, its depth gradually changes from 5um at the starting point to 12um at the end, and the groove width is 3um.

[0012] A method for using an ultrasonic turning and milling precision machining high-performance thread device of the present invention comprises the following steps:

[0013] A method for using an ultrasonic turning and milling precision machining high-performance thread device comprises the following steps:

[0014] Step 1: Establish the x, y, z coordinate system, where x is the feed direction, y is the cutting depth direction, and z is the cutting speed direction. First, the laser vibrometer marks the cutting edge point as the test point. Turn on the ultrasonic power supply, and the piezoelectric actuator starts to drive the tool rod to generate bending vibration and axial vibration. The laser vibrometer collects the path of the test point and obtains the maximum displacement of the test point during the test. , that is, the two points with the largest displacement difference; by collecting the path force to the test point, the maximum displacement along the x, y, and z directions can be obtained respectively. , , The time intervals of arrival are , , , then the average time interval , is the maximum displacement in the X direction, is the maximum displacement in the y direction, is the maximum displacement in the z direction, is the time interval in the X direction, is the time interval in the y direction, is the time interval in the z direction;

[0015] Step 2: Based on the discrete method, solve the stable area of the tool bar during high-speed rotation cutting, and determine the limiting cutting speed within the stable area , cutting depth ;

[0016] Step 3: Carry out ultrasonic cutting force test, fit ultrasonic cutting force with feed rate as parameter, and obtain cutting force coefficient: According to the cantilever beam theory, the displacement of the tool bar in the x and z directions is obtained as , The force at , , the maximum feed rate is , Where l is the length of the shank, E is the elastic modulus of the shank material, and I is the polar moment of inertia of the shank;

[0017] Step 4: The radius of the cutter head is , then the relationship between cutting speed and radius ,in is pi, is the rotational speed;

[0018] The number of teeth on the cutter head is N, and the frequency of the teeth cutting in and out during the cutting process is for , then the time interval is for , n is the cutting speed;

[0019] In order to avoid excessive abnormal vibration caused by frequency overlap during cutting, , and the time interval There is no integer multiple relationship with the average time t; the cutting speed n is determined based on this;

[0020] Step 5: Considering the influence of ultrasonic vibration on cutting process and chip fracture, the cutting depth h should be , , , The minimum value in .

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention is through a composite pre-tightening layer arranged on one side of the tool fixing workbench and a pressure plate shell fixedly connected to the composite prefabricated layer, a connecting part I is provided in the middle of the pressure plate shell, a connecting part II is provided on the upper part, and a floating support plate is provided at the lower part, a fixing part is provided in the middle of the connecting part I and the connecting part II, the lower side surface of the fixing part is fixedly connected to the connecting part I, and the middle side surface is connected to the connecting part II, a bottom support part is provided at the bottom of the fixing part, a motor is provided on the bottom support part, a coupling is provided on the output shaft of the motor, a tool rod is provided on the coupling, and a tool disc is provided on the tool rod, wherein the outer surface of the tool rod is provided with a piezoelectric actuator, and the use method is combined so that the device for ultrasonic turning and milling precision machining of high-performance threads of the present invention can process pipes with performance threads to be machined and improve machining efficiency, workpiece quality and tool life. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of pipeline processing of a performance thread to be processed according to Example 1 of the present invention;

[0024] Figure 2 For the present invention Figure 1 Schematic diagram of the structure of the thread turning and milling device;

[0025] Figure 3 For the present invention Figure 1 A schematic structural diagram of the rake face of the tool in the cutter head;

[0026] Figure 4 For the present invention Figure 1 A schematic structural diagram of the back face of the tool in the cutter head;

[0027] Figure 5 For the present invention Figure 1 Vibration shape diagram of the tool holder.

[0028] In the figure: 1. Pipe with performance thread to be processed, 2. Turning and milling thread device, 3. Cutter head, 4. Cutter rod, 5. First connecting member, 6. Second connecting member, 7. Fixing member, 8. Connecting member II, 9. Pressure plate shell, 10. Connecting member I, 11. Spring, 12. Floating support plate, 13. Damper, 14. Composite pre-tightening layer, 15. Tool fixing workbench, 16. Bottom support member, 17. Fixing member I, 18. Fixing member II, 19. Motor, 20. Coupling, 21. Piezoelectric actuator, 40. Restrictive contact groove, 50. Chip breaker groove, 51. Far end of chip breaker groove, 52. Proximal end of chip breaker groove, 60. Groove. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] like Figure 1-5 As shown, this embodiment includes a tool fixing workbench 15, a composite pre-tightening layer 14 arranged on one side of the tool fixing workbench 15, and a pressure plate shell 9 fixedly connected to the composite prefabricated layer 14; wherein, the tool fixing workbench 15 is fixed to the indexable workbench of the lathe by bolts or a pressure plate; the composite pre-tightening layer 14 is fastened to the tool fixing workbench 15 by bolts; the composite pre-tightening layer is composed of glass fiber, rubber, and glass fiber. Considering the high frequency of chip fracture impact load, the two glass fiber layers are 0.2 times the thickness of the total pre-tightening layer, and the composite pre-tightening layer is approximately 0.8 times the length of the pressure plate and 0.125 times the thickness of the pressure plate, and is fixed to the pressure plate shell 9 by bolts.

[0031] The pressure plate shell 9 is composed of four thin plates with a thickness of 5 mm, which are used to support other parts. The thin plates are connected by bolts. Viscous curing glue is added to the bolts and then tightened to further increase the bonding strength and reduce vibration. In this embodiment, the inner side of the pressure plate shell 9 is hexagonal.

[0032] A connecting piece I10 is provided in the middle part of the pressure plate shell 9, a connecting piece II8 is provided in the upper part, and a floating support plate 12 is provided in the lower part, wherein the connecting piece I10 and the connecting piece II8 are both hexagonal connecting pieces, thereby, the connecting piece I10 and the connecting piece II8 can be fixedly connected to the inner side surface of the pressure plate shell 9. In this embodiment, the connecting piece I10 and the connecting piece II8 are both connected to the pressure plate shell 9 by bolts, and the contact points between the bolts and the pressure plate shell 9, the pressure plate shell 9 and the connecting piece I10 and the connecting piece II8 are all provided with washers composed of a retaining spring and rubber. The washers are used to tighten the connection between the pressure plate shell 9 and the connecting piece I10 and the connecting piece II8 and play a vibration absorbing role.

[0033] A fixing part 7 is provided in the middle of the connecting part I10 and the connecting part II8. The fixing part 7 is hexagonal in shape, so as to facilitate the fixed connection between the fixing part 7 and the connecting part I10 and the connecting part II8. In this embodiment, the material of the fixing part 7 is AL7075, which is light in weight, high in strength, and has a certain toughness. It can reduce vibration and reduce the static deformation of the lathe worktable by reducing the mass of the device. The inner and outer sides of the fixing part 7 are both regular hexagons, and the radius difference between the circles formed by the inner and outer hexagons is 5-8 mm.

[0034] The lower side surface of the fixing member 7 is fixedly connected to the connecting member I10, and the middle side surface is fixedly connected to the connecting member II8, and a bottom support member 16 is provided at the bottom of the fixing member (7). In this embodiment, the bottom of the fixing member 7 is connected to the bottom support member 16 by bolts and bolt glue; at the same time, the bottom support member 16 is also connected to the connecting member I10 by bolts and bolt glue, that is, curing glue is added to the surface of the bolts and then tightened.

[0035] A motor 19 is provided on the bottom support member 16, a coupling 20 is provided on the output shaft of the motor 19, a knife bar 4 is provided on the coupling 20, a knife disc 3 is provided on the knife bar 4, and a piezoelectric actuator 21 is provided on the outer surface of the knife bar 4. In this embodiment, the motor 19 is a high-speed motor, connected to the knife bar 4 through the coupling 20, and drives the knife bar 4 to rotate at high speed;

[0036] The piezoelectric actuator 21 drives the tool bar to generate bending vibration and axial vibration, such as Figure 3 As shown, the piezoelectric actuator 21 is installed at the peak of the vibration mode of the driving knife rod, and counting from the vibration mode node closest to the high-speed motor 19, at the odd peak point, under the energy input of the ultrasonic power supply, the knife rod 4 is driven to swing left and right. In this embodiment, the outer ring of the piezoelectric actuator 21 is connected to the bearing and the fixing part 7, and the inner ring is a composite part composed of a double Z-shaped part and a bearing. The fixing part 7 can not interfere with the movement of the piezoelectric actuator when the knife rod 4 rotates at high speed, and transmits the movement of the piezoelectric actuator 21, driving the knife rod 4 to swing at the ultrasonic frequency.

[0037] The motor 19 is fixedly connected to the fixing member 7 via the fixing member I 17 and the fixing member II 18, wherein the connection between the fixing member I 17 and the motor 19 is the vibration mode of the motor 19; the connection between the fixing member II 18 and the fixing member 7 is the node of the vibration mode of the fixing member 7. In this embodiment, the thickness of the fixing member I 17 and the fixing member II 18 are both 10-15 mm. The vibration mode of the motor 19 and the node of the vibration mode of the fixing member 7 can be obtained by setting boundary conditions according to the working conditions of the motor 18 and performing modal calculation using finite element software.

[0038] A first connecting member 5 and a second connecting member 6 are provided at the upper and lower ends of the piezoelectric actuator 21 and on the outside of the knife rod 4. The inner and outer sides of the first connecting member 5 and the second connecting member 6 are both hexagonal. The inner sides of the first connecting member 5 and the second connecting member 6 are connected to the knife rod 4 through rolling bearings, and the outer sides are fixedly connected to the fixing member 7. The connection between the rolling bearing and the first connecting member 5 and the second connecting member 6 is provided with a vibration-damping and wear-resistant layer composed of asbestos, rubber and glass fiber. Among them, the connection between the first connecting member 5 and the second connecting member 6 and the knife rod 4 is the node of the knife rod 4 at the excitation vibration mode of the piezoelectric actuator 21, which can reduce the dissipation of ultrasonic vibration energy and the vibration transmitted to other connecting members.

[0039] In this embodiment, modal calculation is performed using finite element software to obtain vibration modes, thereby determining that the connection between the first connecting member 5 and the second connecting member 6 and the tool rod 4 is the node of the tool rod 4 at the excitation vibration mode of the piezoelectric actuator 21.

[0040] The cutter disc 3 has a diameter of 4-6 mm and is provided with a cutter. Multiple cutters can be mounted on the cutter disc 3, wherein the cutter rake angle is ≤5° and the clearance angle is ≥15°. A groove is provided on the flank of the cutter, wherein the end of the groove is 4 μm away from the cutting edge. The groove depth is 2 μm-8 μm and the width is 1 μm when extending linearly outward from the cutting edge. The grooves are arranged like veins in a leaf.

[0041] A restrictive contact groove 40 is provided on the front cutting edge of the tool, and the restrictive contact groove 40 is respectively located at 1um, 4um, and 6um away from the cutting edge, with a width of 1.5um and a depth of 2um; a chip breaker groove 50 with a width of 3mm and parallel to the cutting edge is opened at 10um away from the cutting edge, the distal end 51 of the chip breaker groove is 1mm higher than the proximal end, and the proximal end 52 of the chip breaker groove refers to the side close to the cutting edge; the front cutting edge angle is 1°-2°; the back angle of the tool is 10°-20°, and vein-shaped grooves 60 are added to the front cutting edge, with a spacing between the partings of 8-10um, a width of the groove 60 of 1.5-3um, and the direction of the groove 60 is 25° to the cutting edge, maintaining a distance of 2-4um from the cutting edge. When the groove depth extends linearly outward from the cutting edge, its depth gradually changes from 5um at the starting point to 12um at the end, and the groove width is 3um.

[0042] Cutterhead 3 is a micro-cutterhead that drives its attached blade at high speed. Even during normal wear, the blade's flank surface will contact and rub against the machined surface, affecting the machining quality of the threaded contact surface. Considering that during high-speed cutting of high-strength gear materials, the blade is subjected to high cutting forces and thermal loads caused by periodic chip breakage. Under these conditions, both the front and rear flanks of the tool will wear, undergoing plastic deformation, notching wear, and thermal cracking. To improve the tool's wear resistance, high-temperature resistance, and thermal insulation, chipbreaker grooves, specifically micro-grooves, are added to the front and rear flanks of the tool to reduce the contact area and friction between the tool and the chip, as well as the flank surface. The micro-grooves also reduce the length of the tool-chip contact and adhesion zone. Ultrasonic vibration drives the tool back and forth, creating a vacuum effect. The air pressure near the cutting micro-grooves is lower than elsewhere in the micro-grooves, creating a siphon effect that draws the cutting fluid closer to the cutting edge, reducing the cutting edge temperature. A composite coating is then applied to the front and rear flanks of the tool, forming a first layer of TiN, a second layer of TiAlN, and a third layer of TiN. The first coating, TiN, offers high hardness and strength, as well as significant thermal insulation, reducing heat transfer to the tool, lowering tool temperature and minimizing the likelihood of thermal cracking on the cutting edge. The second coating, TiAlN, offers excellent high-temperature resistance and toughness, reducing the effects of thermal shock on the tool and extending tool life. The third coating, TiN, further reduces heat transfer to the tool, supports the second coating, and reduces deformation from impact. The first layer is a physical coating process, creating a significant thermal insulation and strength layer. The second and third layers utilize a chemical coating process, creating layers with significant heat resistance, a certain degree of thermal insulation, and strength, resulting in high bond strength.

[0043] A method for using an ultrasonic turning and milling device for precision machining high-performance threads, comprising the following steps:

[0044] Step 1: Establish an x, y, z coordinate system, where x is the feed direction, y is the cutting depth direction, and z is the cutting speed direction. First, the laser vibrometer marks the cutting edge point as the test point, turns on the ultrasonic power supply, and the piezoelectric actuator 21 starts to drive the tool rod 4 to generate bending vibration and axial vibration. The laser vibrometer collects the path of the test point and obtains the maximum displacement of the test point during the test. , that is, the two points with the largest displacement difference; by collecting the path force to the test point, the maximum displacement along the x, y, and z directions can be obtained respectively. , , The time intervals of arrival are , , , then the average time interval , is the maximum displacement in the X direction, is the maximum displacement in the y direction, is the maximum displacement in the z direction, is the time interval in the X direction, is the time interval in the y direction, is the time interval in the z direction;

[0045] Step 2: According to the discrete method, solve the stable area of the tool bar 4 when it rotates at high speed, and determine the limiting cutting speed in the stable area , cutting depth ;

[0046] Step 3: Carry out ultrasonic cutting force test, fit ultrasonic cutting force with feed rate as parameter, and obtain cutting force coefficient: According to the cantilever beam theory, the displacement of the tool bar 4 in the x and z directions is obtained as , The force at , , the maximum feed rate is , Where l is the length of the shank, E is the elastic modulus of the shank material, and I is the polar moment of inertia of the shank;

[0047] Step 4: The radius of the cutter head is , then the relationship between cutting speed and radius ,in is pi, is the rotational speed;

[0048] The number of teeth on the cutter head is N, and the frequency of the teeth cutting in and out during the cutting process is for , then the time interval is for , n is the cutting speed;

[0049] In order to avoid excessive abnormal vibration caused by frequency overlap during cutting, , and the time interval There is no integer multiple relationship with the average time t; the cutting speed n is determined based on this

[0050] Step 5: Considering the influence of ultrasonic vibration on cutting process and chip fracture, the cutting depth h should be , , , The minimum value in .

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the technical solutions of the present invention have been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A device for ultrasonic turning and milling precision machining of high-performance threads, characterized by: It comprises a tool fixing workbench (15), a composite pre-tightening layer (14) arranged on one side of the tool fixing workbench (15), and a pressure plate shell (9) fixedly connected to the composite pre-tightening layer (14); a connecting member I (10) is provided in the middle of the pressure plate shell (9), a connecting member II (8) is provided in the upper part, and a floating support plate (12) is provided in the lower part; a fixing member (7) is provided in the middle of the connecting member I (10) and the connecting member II (8); the lower side surface of the fixing member (7) is fixedly connected to the connecting member I (10), and the middle side surface is connected to the connecting member II (8); a bottom support member (16) is provided at the bottom of the fixing member (7); a motor (19) is provided on the bottom support member (16); a coupling (20) is provided on the output shaft of the motor (19); a tool rod (4) is provided on the coupling (20); a tool disc (3) is provided on the tool rod (4); wherein a piezoelectric actuator (21) is provided on the outer surface of the tool rod (4); The motor (19) is fixedly connected to the fixing member (7) via the fixing member I (17) and the fixing member II (18), wherein the connection point between the fixing member I (17) and the motor (19) is the vibration mode of the motor (19); and the connection point between the fixing member II (18) and the fixing member (7) is the node of the vibration mode of the fixing member (7).

2. The device for ultrasonic milling and precision machining of high-performance threads according to claim 1, characterized in that: The inner side of the pressure plate shell (9) is hexagonal, the connecting member I (10) and the connecting member II (8) are both hexagonal connecting members, and the fixing member (7) is hexagonal.

3. The device for ultrasonic milling and precision machining of high-performance threads according to claim 2, characterized in that: A first connecting member (5) and a second connecting member (6) are provided at the upper and lower ends of the piezoelectric actuator (21) and on the outer side of the knife rod (4); the inner and outer sides of the first connecting member (5) and the second connecting member (6) are both hexagonal; the inner sides of the first connecting member (5) and the second connecting member (6) are connected to the knife rod (4) through rolling bearings, and the outer sides are fixedly connected to the fixing member (7); wherein the connection between the first connecting member (5) and the second connecting member (6) and the knife rod (4) is the node of the knife rod (4) excitation vibration mode of the piezoelectric actuator (21).

4. The device for ultrasonic milling and precision machining of high-performance threads according to claim 1 or 3, characterized in that: The cutter disc (3) has a diameter of 4-6 mm, and a cutter is provided on the cutter disc (3), wherein a plurality of cutters can be installed on the cutter disc (3).

5. The device for ultrasonic milling and precision machining of high-performance threads according to claim 4, characterized in that: The tool has a front angle of ≤5° and a back angle of ≥15°; a groove is provided on the back face of the tool, the end of the groove is 4um away from the cutting edge, the depth of the groove is 2um-8um and the width is 1um when extended linearly outward from the cutting edge, and the plurality of grooves are arranged like veins in leaves.

6. The device for ultrasonic milling and precision machining of high-performance threads according to claim 5, characterized in that: The tool rake face is provided with a restrictive contact groove, which is located 1um, 4um, and 6um away from the cutting edge, with a width of 1.5um and a depth of 2um; a chip breaker groove with a width of 3mm and parallel to the cutting edge is opened 10um away from the cutting edge, and the distal end face of the chip breaker groove is 1mm higher than the proximal end face, and the proximal end face refers to the side close to the cutting edge; the rake face angle is 1°-2°; the back angle of the tool is 10°-20°, and grooves arranged in a vein-like manner are added to the rake face. The spacing between the partings is 8-10um, the groove width is 1.5-3um, the groove direction is 25° with the cutting edge, and a distance of 2-4um is maintained from the cutting edge. When the groove depth extends linearly outward from the cutting edge, its depth gradually changes from 5um at the starting point to 12um at the end, and the groove width is 3um.

7. A method for using an ultrasonic turning and milling device for precision machining high-performance threads, characterized by: The following steps are included: Step 1: Establish an x, y, z coordinate system, where x is the feed direction, y is the cutting depth direction, and z is the cutting speed direction. First, the laser vibrometer marks the cutting edge point as the test point, turns on the ultrasonic power supply, and the piezoelectric actuator (21) starts to drive the tool rod (4) to generate bending vibration and axial vibration. The laser vibrometer collects the path of the test point and obtains the maximum displacement of the test point during the test. , that is, the two points with the largest displacement difference; by collecting the path force to the test point, the maximum displacement along the x, y, and z directions can be obtained respectively. , , The time intervals of arrival are , , , then the average time interval , is the maximum displacement in the X direction, is the maximum displacement in the y direction, is the maximum displacement in the z direction, is the time interval in the X direction, is the time interval in the y direction, is the time interval in the z direction; Step 2: Based on the discrete method, solve the stable area of the tool bar (4) during high-speed rotation cutting, and determine the limiting cutting speed within the stable area , cutting depth ; Step 3: Carry out ultrasonic cutting force test, fit ultrasonic cutting force with feed rate as parameter, and obtain cutting force coefficient: According to the cantilever beam theory, the displacement of the tool bar (4) in the x, z direction is obtained as , The force at , , the maximum feed rate is , The minimum value in; where l is the length of the arbor, E is the elastic modulus of the arbor material, I is the polar moment of inertia of the arbor; Step 4; The radius of the cutter head is , then the relationship between cutting speed and radius ,in, is pi, is the rotational speed; The number of teeth on the cutter head is N, and the frequency of the teeth cutting in and out during the cutting process is for , then the time interval is for , n is the cutting speed; In order to avoid excessive abnormal vibration caused by frequency overlap during cutting, , and the time interval There is no integer multiple relationship with the average time t; the cutting speed n is determined based on this; Step 5: Considering the influence of ultrasonic vibration on cutting process and chip fracture, the cutting depth h should be , , , The minimum value in .

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