Improved axial vibration chip breaking tool holder and vibration control method

Abstract

An improved axial vibration chip breaking handle and vibration control method relate to the technical field of machining equipment, the chip breaking handle comprises a shell, a vibration mechanism and a torque transmission mechanism, the vibration mechanism comprises a vibration execution shaft and a driving device, the torque transmission mechanism comprises a plurality of positioning grooves arranged on the inner wall of the shell and a row of balls arranged in the positioning grooves; the vibration control method comprises determining the type of machining material, the cutting linear velocity and the chip breaking length; the axial vibration frequency of the vibration execution shaft is calculated according to the cutting linear velocity and the chip breaking length; whether the axial vibration frequency is in the design range is judged; the rotating speed of the flow guide disc is calculated according to the axial vibration frequency and the speed reduction ratio of the speed reducer, and then the fluid pressure is adjusted. In the application, the rotating speed of the flow guide disc is more stable, the rotating speed is higher, the output torque is high, the assembly precision between the vibration execution shaft and the shell is higher, and the specific control method of the vibration frequency and amplitude of the vibration execution shaft is given.

Description

Technical Field

[0001] This invention relates to the field of machining equipment technology, and in particular to an improved axial vibration chip breaking tool holder and vibration control method. Background Technology

[0002] In metal reaming, each rotation of the tool spindle produces a continuous chip along the hole wall. This continuous chip elongation is a major cause of chip entanglement, chip buildup, and hole wall scratching, necessitating a solution for controllable chip breaking. Currently, many vibratory chip-breaking toolholders exist, using toolholder vibration to enable chip breaking during machining. The mainstream vibratory chip-breaking methods include hydraulic pulse type (such as Schenk VibroFlex) and piezoelectric ceramic driven type (such as Schenk LiquiFlex). Hydraulic pulse type vibratory chip-breaking toolholders utilize the machine tool's hydraulic system or a separate hydraulic unit, controlled by precise hydraulic valves, to periodically inject and release hydraulic oil into the piston chamber inside the toolholder, thereby driving the toolholder to generate axial pulse vibration. Piezoelectric ceramic driven vibratory chip-breaking toolholders utilize the inverse piezoelectric effect of piezoelectric ceramic materials. When a high-frequency voltage is applied to the piezoelectric ceramic stack, its length undergoes a slight change, thereby driving the connected mechanism to generate high-frequency micro-vibration.

[0003] Patent application CN120680033A discloses a hydraulic axial vibration chip-breaking tool holder and a vibration chip-breaking method. Using the machine tool's own coolant as a power source, it employs a clever and simple mechanical structure to enable the tool to perform axial vibration chip breaking and cutting during hole machining. Its driving device includes a fluid-driven rotating assembly. Fluid enters the working chamber from the side wall of the housing, driving the fluid-driven rotating assembly to rotate, and then flows out from the side wall of the housing. However, in actual use, because the housing itself is also rotating at high speed, the centrifugal force it generates adversely affects the fluid flow process, resulting in unstable rotational speed of the fluid-driven rotating assembly, low speed, low output torque, and the chip-breaking effect not meeting expectations. Furthermore, there is still a problem of low assembly precision between the vibration actuator shaft and the housing, leading to large radial displacement of the vibration actuator shaft, affecting the control of the vibration frequency and the machining accuracy of the tool. Summary of the Invention

[0004] To address the problems of low output torque and low assembly accuracy of fluid-driven rotary components in existing technologies, this invention provides an improved axial vibration chip breaking tool holder and vibration control method.

[0005] This invention provides the following technical solution: an improved axial vibration chip breaker tool holder, comprising: The housing is connected to the machine tool connecting handle via a transmission. A vibration mechanism includes a vibration actuator shaft that cooperates with a housing and a drive device for driving the vibration actuator shaft to reciprocate along the axial direction of the housing. The drive device includes a guide plate rotatably connected inside the housing, a reducer driven by the guide plate, a rolling assembly disposed on the end of the vibration actuator shaft facing the reducer, and a reset assembly for moving the vibration actuator shaft towards the reducer. A liquid inlet pipe is disposed in the center of the guide plate, and a spray port communicating with the liquid inlet pipe is disposed on the side wall of the guide plate. Fluid ejected from the spray port generates a reaction force that drives the guide plate to rotate. The housing also has a drain port. The end face of the reducer output shaft is inclined. The rolling assembly includes a universal ball eccentrically disposed relative to the reducer output shaft, and the universal ball contacts the inclined surface. The reset assembly includes an elastic element disposed between the vibration actuator shaft and the housing. The torque transmission mechanism includes multiple positioning grooves disposed on the inner wall of the housing and a row of balls disposed in the positioning grooves, the positioning grooves extending along the axial direction of the housing.

[0006] Preferably, the housing includes a flow guide, a partition, and a transmission part. The flow guide and the partition form a working cavity. The flow guide plate is rotatably connected to the flow guide and the partition. The flow guide is provided with a central flow channel communicating with the liquid inlet pipe. The flow guide is provided with a drain port on its side wall. The vibration actuator shaft is clearance-fitted with the transmission part. The partition is bolted to a limit block. The reducer is disposed between the limit block and the partition.

[0007] Preferably, the reducer is a planetary reducer, the drive shaft of the guide disc is connected to the sun gear of the planetary reducer, and the output end of the planetary reducer is detachably connected to a rotating head, the end face of the rotating head facing the vibration actuator shaft is the inclined surface.

[0008] Preferably, the inclination angle of the inclined plane is 1-4°.

[0009] Preferably, the eccentric distance between the omnidirectional ball and the output shaft is 0.5~4 mm.

[0010] Preferably, the multiple positioning grooves are symmetrical about the central axis of the housing.

[0011] A vibration control method for a vibrating tool holder, applied to an improved axial vibration chip breaker tool holder, the vibration control method comprising the following steps: Step 1: Determine the type of material to be processed, the cutting speed, and the chip breaking length; Step 2: Calculate the axial vibration frequency of the vibratory actuator shaft based on the cutting speed and chip breaking length. The formula for calculating the axial vibration frequency is as follows:

[0012] Among them, f v V is the axial vibration frequency. c L is the cutting linear velocity. chip Where k is the chip breaking length and k is the tool tip number adjustment coefficient; Step 3: Determine whether the axial vibration frequency is within the design range. If it is not within the design range, adjust the cutting speed and / or chip breaking length until the axial vibration frequency meets the design range. Step 4: Calculate the rotational speed of the guide plate based on the axial vibration frequency and the reduction ratio of the reducer, and then adjust the fluid pressure.

[0013] Preferably, when the number of cutting edges of the tool is 2, the value range of k is [0.85, 0.9], when the number of cutting edges is 3, the value of k is 1, and when the number of cutting edges is 4, the value range of k is [1.1, 1.2].

[0014] Preferably, the design range includes a reference range, a common range, and a global adaptation range, wherein the reference range is 50~70Hz, the common range is 40~80Hz, and the global adaptation range is 30~108Hz.

[0015] Preferably, the vibration control method further includes amplitude adjustment, wherein the axial vibration amplitude of the tool is less than the actual chip thickness under the current working conditions.

[0016] The beneficial effects of this invention are: the fluid ejected from the injection ports around the flow guide cavity generates a reaction force that drives the flow guide disk to rotate; the centrifugal force generated by the rotation of the shell does not hinder the fluid flow; the speed of the flow guide disk is stable; the fluid work efficiency is improved; and both the speed and output torque are improved. Adding a speed reducer to the guide plate drive shaft reduces the speed and increases the torque, and the vibration frequency of the vibratory actuator shaft can be controlled by adjusting the reduction ratio; The torque transmission mechanism has been improved, assembly accuracy has been enhanced, and the probability of radial displacement of the vibration actuator shaft has been reduced. A specific control method for the vibration frequency and amplitude of the vibratory actuator is presented, which enables controllable chip breaking for different processed materials. It has the versatility to fully adapt to various low-carbon steel, quenched and tempered alloy steel and stainless steel hole expansion conditions, and controls the chip breaking length within a reasonable range. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of one embodiment of a chip-breaking tool holder.

[0018] Figure 2 This is a cross-sectional view of one embodiment of the flow guide plate.

[0019] Figure 3 A cross-sectional view of one embodiment of a vibratory actuator shaft.

[0020] Reference numerals: 11, guide section; 12, baffle plate; 13, transmission section; 14, central flow channel; 21, guide plate; 211, inlet pipe; 212, drive shaft; 213, guide groove; 214, injection nozzle; 215, L-shaped groove; 22, reducer; 221, limit block; 222, rotating head; 223, inclined plane; 23, vibration actuator shaft; 24, rolling assembly; 31, positioning groove; 32, ball bearing; 40, machine tool connecting handle. Detailed Implementation

[0021] The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings and reference numerals, so that those skilled in the art can implement them after reading this specification. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0022] This invention provides, for example Figure 1-3 An improved axial vibration chip breaker tool holder is shown, comprising a housing, a vibration mechanism, and a torque transmission mechanism.

[0023] Please refer to Figure 1 The housing includes a flow guide 11, a partition 12, and a transmission part 13, all bolted together. The flow guide 11 is connected to the machine tool connecting handle 40 via a key or other means. The machine tool connecting handle 40 drives the housing to rotate. Both the flow guide 11 and the machine tool connecting handle 40 are provided with a central flow channel 14, through which fluid flows into the housing under positive pressure. The machine tool connecting handle 40 is prior art and is not within the scope of this application. The fluid includes the machine tool's coolant, but this invention does not limit the fluid to coolant; those skilled in the art can choose other fluids.

[0024] The flow guide 11 and the partition 12 form a working chamber. The flow guide plate is rotatably connected in the working chamber. The flow guide 11 is also provided with a drain port to discharge the fluid in the working chamber. The transmission part 13 is also provided with a tubular inner cavity.

[0025] The vibration mechanism includes a vibration actuation shaft 23 connected to the cutting tool and a drive device. The vibration actuation shaft 23 is inserted into the inner cavity of the transmission part 13 and is clearance-fitted with the transmission part 13. The drive device drives the vibration actuation shaft 23 to reciprocate along the axial direction of the housing, thereby generating vibration at a certain frequency to achieve chip breaking. The drive device includes a guide plate 21 rotatably connected in the guide cavity, a reducer 22 drivenly connected to the guide plate 21, a rolling assembly 24 disposed on the end of the vibration actuation shaft 23 facing the reducer 22, and a reset assembly.

[0026] The guide plate 21 has a liquid inlet pipe in the center, which is connected to the central flow channel 14. Its side wall has multiple spray nozzles connected to the liquid inlet pipe. Under positive pressure, fluid enters through the central flow channel 14 and the liquid inlet pipe, and then sprays out from the spray nozzles. The resulting reaction force drives the guide plate 21 to rotate.

[0027] Please refer to Figure 1 , 2 In one embodiment, a liquid inlet pipe 211 coaxial with the central flow channel 14 is provided on one side of the flow guide plate 21. The liquid inlet pipe 211 is rotatably connected to the flow guide part 11 through a bearing, and the liquid inlet pipe 211 is inserted into the central flow channel 14 to communicate with the central flow channel 14. A drive shaft 212 is provided on the other side of the disc-shaped structure, and the drive shaft 212 is rotatably connected to the partition plate 12. The interior of the flow guide plate 21 is provided with a flow guide cavity composed of multiple flow guide grooves 213. The multiple flow guide grooves 213 are symmetrical about the central axis of the flow guide plate 21. The outer wall of the flow guide plate 21 is provided with multiple L-shaped grooves 215. The flow guide grooves 213 extend to the side wall of the L-shaped grooves 215 to form a spray nozzle 214. The inner and outer walls of the flow guide grooves 213 extend along curves, and the cross-sectional area of ​​the flow guide grooves 213 gradually decreases from the inside to the outside, increasing the flow velocity of the fluid ejected from the spray nozzle 214, thereby increasing the rotational speed and output torque of the flow guide plate 21.

[0028] Compared with the prior art, in this invention, the fluid flows from the inside to the outside, and the centrifugal force generated when the shell rotates does not hinder the fluid flow. The rotational speed of the guide plate 21 is stable, the work efficiency of the fluid is improved, and the rotational speed and output torque are also increased accordingly. However, this improvement will lead to a higher upper limit of rotational speed, causing the vibration frequency of the vibrating actuator shaft to exceed the vibration frequency range corresponding to the optimal chip breaking length range of some materials. Therefore, this invention also includes a speed reducer 22.

[0029] The speed reducer 22 can be a planetary speed reducer. Please refer to [reference needed]. Figure 1 The partition 12 is bolted to a limit block 221, and the reducer 22 is disposed between the limit block 221 and the partition 12. The sun gear of the planetary reducer is connected to the drive shaft 212, and the output shaft of the planetary reducer is detachably connected to a rotating head 222. The end face of the rotating head 222 facing the vibrating actuation shaft 23 is an inclined surface 223.

[0030] The rolling assembly 24 can be a omnidirectional ball, which is disposed at the end of the vibration actuation shaft 23 facing the reducer 22, and the omnidirectional ball is eccentrically disposed relative to the output shaft of the reducer 22. The reset assembly includes an elastic element disposed between the vibration actuation shaft 23 and the transmission part 13. The elastic element can be a spring, bellows, etc., which can move the vibration actuation shaft 23 toward the reducer 22, ensuring that the omnidirectional ball is always in contact with the inclined surface 223, and that the omnidirectional ball rolls relative to the inclined surface.

[0031] Please refer to Figure 1 Due to the eccentric design of the omnidirectional ball joint, the higher and lower parts of the inclined plane 223 will periodically contact the omnidirectional ball joint as it rotates, creating an axial distance difference at the contact positions. When the higher part of the inclined plane 223 contacts the omnidirectional ball joint, such as... Figure 1 As shown, the vibration actuator 23 moves upward to its highest point under the action of the elastic element; the inclined plane 223 rotates, and its lower part gradually rotates to the universal ball, pressing the vibration actuator 23 downward to its lowest point; the inclined plane continues to rotate, and its higher part gradually rotates to the universal ball, and the vibration actuator 23 returns to its highest point under the action of the elastic element. The vibration actuator 23 drives the tool to vibrate according to the above process, and the reducer output shaft completes one vibration per revolution.

[0032] Preferably, the inclination angle of the inclined plane is 1~4°, and the eccentric distance between the universal ball and the output shaft of the reducer is 0.5~4 mm. The inclination angle and eccentric distance can be adjusted to adjust the vibration amplitude of the vibration actuator shaft 23.

[0033] A torque transmission mechanism is also provided between the housing and the vibration actuation shaft 23, causing the vibration actuation shaft 23 to rotate together with the housing, thereby causing the tool connected to the vibration actuation shaft 23 to rotate. Please refer to... Figure 1 , 3 The torque transmission mechanism includes a plurality of positioning grooves 31 disposed on the inner wall of the transmission part 13 and a row of balls 32 disposed within the positioning grooves 31, wherein the positioning grooves 31 extend along the axial direction of the housing. Preferably, the plurality of positioning grooves 31 are symmetrical about the central axis of the housing.

[0034] The manufacturing process for ball bearings is mature, and under current technological conditions, the control of geometric precision such as diameter deviation, roundness, and diameter variation of the ball bearings has reached a high level, resulting in good reliability. Compared with existing technologies, the torque transmission mechanism used in this invention has a simpler structure and less error accumulation. Combining these factors, the assembly precision between the vibration actuator shaft 23 and the transmission unit 13 is improved to the micrometer level, reducing the probability of radial displacement of the vibration actuator shaft 23.

[0035] This invention also provides a vibration control method for a vibrating tool holder, applied to the improved axial vibration chip-breaking tool holder for metal reaming. The vibration control method does not set a fixed axial vibration frequency, but rather derives the axial vibration frequency based on the cutting speed of different workpiece materials and a reasonable chip breaking length through a physical cutting model. Finally, the vibration frequency is controlled by adjusting the pressure of the feed fluid. This method covers reaming conditions for carbon steel, alloy steel, stainless steel, and other metal materials, achieving universal, controllable, and high-precision hydraulic vibration chip-breaking machining.

[0036] The vibration control method includes the following steps: Step 1: Determine the type of material to be processed, the cutting speed, and the chip breaking length. Specifically, first determine the type of material to be processed, and then determine the optimal cutting speed and chip breaking length for reaming based on historical data. This avoids excessively long chips that entangle the tool, and also avoids excessively short chips that break off and cause powdery debris to wear the cutting edge and scratch the hole wall, thus balancing processing stability and hole accuracy.

[0037] In one embodiment, for low-carbon steel with a hardness between HB200 and HB260, the preferred cutting speed is 85 to 110 m / min and the chip length is 18 to 35 mm; for quenched and tempered alloy steel with a hardness between HB260 and HRC30, the preferred cutting speed is 65 to 85 m / min and the chip length is 15 to 30 mm; for 304 / 316 austenitic stainless steel, the preferred cutting speed is 45 to 65 m / min and the chip length is 10 to 25 mm.

[0038] Step 2: Calculate the axial vibration frequency of the vibratory actuator shaft based on the cutting speed and chip breaking length. The formula for calculating the axial vibration frequency is as follows:

[0039] Among them, f v V is the axial vibration frequency. c L is the cutting linear velocity. chip Where is the chip breaking length, and k is the adjustment coefficient for the number of cutting edges.

[0040] The above calculation formula is a general calculation formula derived from the physical cutting model established by the relationship between the cutting trajectory unfolding length and the chip growth rate. It can be seen that the theoretical vibration frequency is determined by the cutting linear velocity and the target chip length. The number of cutting edges of the tool changes the smoothness of continuous chip formation. When using tools with different cutting edge types, a small adaptive correction of the vibration frequency is required.

[0041] In one embodiment, when the number of cutting edges is 2, the value of k ranges from [0.85, 0.9]. The cutting process exhibits noticeable intervals, resulting in longer chip stretching time and longer chips at the same frequency, necessitating a reduction in the theoretical calculation frequency. When the number of cutting edges is 3, k is 1, leading to uniform cutting continuity, stable impact, and stable chip formation, perfectly matching the theoretical vibration frequency, making it the optimal cutting edge type for this invention. When the number of cutting edges is 4, k ranges from [1.1, 1.2]. This results in continuous, uninterrupted cutting, the strongest chip elongation, and the greatest likelihood of tool entanglement, requiring an increase in the theoretical calculation frequency.

[0042] Step 3: Determine whether the axial vibration frequency calculated in Step 2 is within the design range. If it is not within the design range, adjust the cutting speed and / or chip breaking length until the axial vibration frequency meets the design range. The design range refers to the allowable working range of the chip breaker. The design range of the chip breaker can be determined and graded based on factors such as the frequency of use in actual working conditions, the load-bearing capacity of the torque transmission mechanism, and the service life of the components.

[0043] The design range includes a baseline range, a commonly used range, and a fully adaptable range. The baseline range serves as the design benchmark for the chip breaker, ensuring the entire system operates within the range of optimal torque and highest efficiency. The commonly used range covers over 90% of mass production conditions for steel, guaranteeing stable chip breaking performance while adapting to the power output characteristics of the chip breaker, providing sufficient torque and smooth operation. The fully adaptable range further covers all extreme machining conditions, such as low-speed finishing of stainless steel and high-speed roughing of carbon steel, providing full-scenario adaptability. In one embodiment, the baseline range is 50~70Hz, the commonly used range is 40~80Hz, and the fully adaptable range is 30~108Hz. In actual operating conditions, the appropriate design range is selected based on the needs.

[0044] Step 4: The output shaft of the reducer completes one vibration per revolution. By designing a suitable reduction ratio, the rotational speed of the guide plate required to achieve the axial vibration frequency determined in Step 3 can be calculated. In a specific working condition of the chip breaker, the correspondence between the rotational speed of the guide plate and the fluid pressure fed into the chip breaker is determined. From this, the fluid pressure required to achieve the required rotational speed can be obtained.

[0045] Furthermore, the vibration control method also includes amplitude adjustment. The axial vibration amplitude of the tool is less than the actual chip thickness under the current working conditions to ensure that the vibration is only used for periodic chip breaking and does not increase the cutting allowance. While achieving chip breaking, it also ensures the dimensional accuracy and surface roughness of the workpiece hole wall, balancing chip breaking effect and machining quality. Specifically, the amplitude of the vibration actuator shaft can be adjusted by adjusting the tilt angle of the inclined plane and the eccentric distance between the universal ball and the reducer output shaft.

[0046] The technical solution provided by this invention can be used for metal hole expansion processing. Those skilled in the art can also use the above technical solution to achieve processing of other methods or other materials.

[0047] The above describes one or more embodiments of the present invention in a relatively specific and detailed manner, but it should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. An improved axial vibration chip breaker tool holder, characterized in that, include: The housing is connected to the machine tool connecting handle via a transmission. A vibration mechanism includes a vibration actuator shaft that cooperates with a housing and a drive device for driving the vibration actuator shaft to reciprocate along the axial direction of the housing. The drive device includes a guide plate rotatably connected inside the housing, a reducer driven by the guide plate, a rolling assembly disposed on the end of the vibration actuator shaft facing the reducer, and a reset assembly for moving the vibration actuator shaft towards the reducer. A liquid inlet pipe is disposed in the center of the guide plate, and a spray port communicating with the liquid inlet pipe is disposed on the side wall of the guide plate. Fluid ejected from the spray port generates a reaction force that drives the guide plate to rotate. The housing also has a drain port. The end face of the reducer output shaft is inclined. The rolling assembly includes a universal ball eccentrically disposed relative to the reducer output shaft, and the universal ball contacts the inclined surface. The reset assembly includes an elastic element disposed between the vibration actuator shaft and the housing. The torque transmission mechanism includes multiple positioning grooves disposed on the inner wall of the housing and a row of balls disposed in the positioning grooves, the positioning grooves extending along the axial direction of the housing.

2. The improved axial vibration chip breaker tool holder according to claim 1, characterized in that, The housing includes a flow guide, a partition, and a transmission part. The flow guide and the partition form a working cavity. The flow guide plate is rotatably connected to the flow guide and the partition. The flow guide is provided with a central flow channel communicating with the liquid inlet pipe. The flow guide is provided with a drain port on its side wall. The vibration actuator shaft is clearance-fitted with the transmission part. The partition is bolted to a limit block. The reducer is disposed between the limit block and the partition.

3. The improved axial vibration chip breaker tool holder according to claim 1, characterized in that, The reducer is a planetary reducer. The drive shaft of the guide plate is connected to the sun gear of the planetary reducer. The output end of the planetary reducer is detachably connected to a rotating head. The end face of the rotating head facing the vibration actuation shaft is the inclined surface.

4. The improved axial vibration chip breaker tool holder according to claim 1, characterized in that, The inclination angle of the inclined plane is 1-4°.

5. An improved axial vibration chip breaker tool holder according to claim 1, characterized in that, The eccentric distance between the omnidirectional ball and the output shaft is 0.5~4 mm.

6. An improved axial vibration chip breaker tool holder according to claim 1, characterized in that, Multiple positioning grooves are symmetrical about the central axis of the housing.

7. A vibration control method for a vibrating tool holder, characterized in that, The vibration control method, applied to the improved axial vibration chip breaker tool holder as described in any one of claims 1 to 6, comprises the following steps: Step 1: Determine the type of material to be processed, the cutting speed, and the chip breaking length; Step 2: Calculate the axial vibration frequency of the vibratory actuator shaft based on the cutting speed and chip breaking length. The formula for calculating the axial vibration frequency is as follows: ； Among them, f v V is the axial vibration frequency. c L is the cutting linear velocity. chip Where k is the chip breaking length and k is the tool tip number adjustment coefficient; Step 3: Determine whether the axial vibration frequency is within the design range. If it is not within the design range, adjust the cutting speed and / or chip breaking length until the axial vibration frequency meets the design range. Step 4: Calculate the rotational speed of the guide plate based on the axial vibration frequency and the reduction ratio of the reducer, and then adjust the fluid pressure.

8. The vibration control method according to claim 7, characterized in that, When the number of cutting edges of the tool is 2, the value of k is in the range of [0.85, 0.9]. When the number of cutting edges is 3, the value of k is 1. When the number of cutting edges is 4, the value of k is in the range of [1.1, 1.2].

9. The vibration control method according to claim 7, characterized in that, The design range includes a reference range, a common range, and a global adaptation range. The reference range is 50~70Hz, the common range is 40~80Hz, and the global adaptation range is 30~108Hz.

10. The vibration control method according to claim 7, characterized in that, The vibration control method also includes amplitude adjustment, where the axial vibration amplitude of the tool is less than the actual chip thickness under the current working conditions.

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