Water drop shot peening processing device and processing method

Abstract

The present invention discloses a water drop shot peening device, comprising a multi-degree-of-freedom robot arm, a high-pressure nozzle fixedly connected to the end of the robot arm, a water drop forming device fixedly connected to the outlet end of the high-pressure nozzle, a variable-angle nozzle connected to the water outlet of the water drop forming device, and the function of the water drop forming device is to convert the water from the high-pressure nozzle into a string of water droplets that are sprayed from the variable-angle nozzle; a high-speed camera is provided near the water drop forming device for photographing the water droplets sprayed from the water drop forming device, a workpiece moving platform is provided below the water drop forming device for placing the workpiece to be processed, and the workpiece moving platform is mounted on two parallel slide rails; the high-speed camera and the workpiece moving platform are both connected to a computer. The present invention also discloses a method for shot peening using the above-mentioned device. The method of the present invention utilizes a string of water droplets for shot peening, and has the characteristics of being able to process the inner and outer surfaces of the workpiece, being low in cost and having good processing performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of part surface strengthening and sheet metal forming, and in particular relates to a water drop shot blasting device. The present invention also relates to a method for shot blasting using the device. Background Art

[0002] Shot peening is a process for strengthening the surface of metal parts and shaping sheet metal. Available methods include shot peening, laser peening, ultrasonic peening, cavitation water peening, and water jet peening. Shot peening uses air pressure or the centrifugal force of an impeller to propel projectiles (such as steel, cast iron, or glass shot) into contact with the surface of a part, strengthening or shaping the part. Laser peening uses a high-power pulsed laser beam to induce shock waves to strengthen or shape parts. Ultrasonic peening uses an ultrasonic transducer and horn to drive a striker to impact the part surface at high speed. Alternatively, it uses an ultrasonic transducer and horn to propel a projectile through the opening of the part cavity, causing it to move at high speed to impact the inner surface of the part, strengthening or shaping the part. Cavitation water peening uses the impact force generated by the collapse of cavitation bubbles in a high-speed, high-pressure water jet to strengthen the part surface. Water jet peening uses a high-pressure water jet to directly impact the part surface, or uses abrasive particles mixed in the high-pressure water jet to impact the part surface, strengthening or shaping the part.

[0003] The above-mentioned shot peening processes achieve the purpose of shot peening in different ways, and each has its own advantages and disadvantages in engineering applications. In actual engineering applications, there are problems such as complex projectile collection and filtration systems, difficult inner cavity processing, and high jet pressure requirements. Summary of the Invention

[0004] The purpose of the present invention is to provide a water drop shot peening processing device, which uses a string of water drops for shot peening processing and has the characteristics of being able to process the inner and outer surfaces of a workpiece, low cost and good processing performance.

[0005] Another object of the present invention is to provide a method for water drop shot blasting using the above device.

[0006] The technical solution adopted in the present invention is a water drop shot peening processing device, comprising a multi-degree-of-freedom robot arm, a high-pressure nozzle fixedly connected to the end of the robot arm, a water drop forming device fixedly connected to the outlet end of the high-pressure nozzle, a variable-angle nozzle connected to the water outlet of the water drop forming device, and the function of the water drop forming device is to convert the water from the high-pressure nozzle into a string of water droplets and spray them from the variable-angle nozzle; a high-speed camera is arranged near the water drop forming device for photographing the water droplets sprayed by the water drop forming device, and a workpiece moving platform is arranged below the water drop forming device for placing the workpiece to be processed, and the workpiece moving platform is installed on two parallel slide rails; the high-speed camera and the workpiece moving platform are both connected to a computer, and the computer is used to store and analyze the shape and running speed data of the water droplets photographed by the high-speed camera, and control the movement of the workpiece moving platform.

[0007] The present invention is also characterized in that:

[0008] The water droplet forming device A includes a first valve body and a first valve core. The first valve core extends into the high-pressure fluid flow channel in the first valve body. The other end of the first valve core is connected to a connecting rod, and the other end of the connecting rod is connected to an eccentric wheel. The eccentric wheel is installed on the output shaft of the motor, and the motor is fixed on the motor support plate; the connecting rod, eccentric wheel, motor and motor support plate are all installed in the shell, and the shell is connected to the first valve body through a first flange; the high-pressure nozzle is connected to the first valve body through the flange of the first valve body.

[0009] The water droplet forming device B includes a second valve body and a second valve core. The second valve core extends into the high-pressure fluid flow channel in the second valve body. The other end of the second valve core is connected to the ultrasonic transducer a. The second valve body and the ultrasonic transducer a are connected through a second flange. The high-pressure nozzle is connected to the second valve body through the flange of the second valve body. The ultrasonic transducer a is connected to the ultrasonic generator a.

[0010] Ultrasonic transducer a includes a second front end cover, a second piezoelectric ceramic, a second rear end cover and a second amplitude rod connected in sequence. The above four components are connected together by a second bolt; the second amplitude rod is connected to the second valve body through a second flange, and the end of the second amplitude rod is also connected to the second valve core. After connection, the second valve core is radially fixed and axially movable.

[0011] An axial step countersunk hole is provided at the center of the end of the second amplitude-changing rod, with the coarse diameter end of the step countersunk hole on the outside and the fine diameter end on the inside. The diameter of the fine diameter end is equal to the diameter of the second valve core, and the inner wall of the fine diameter end hole is provided with two opposite rectangular grooves, the depth of the grooves is less than the radius difference between the coarse and fine diameter end holes; two rectangular protrusions with the same size and corresponding positions as the rectangular grooves are provided on the outer wall of the end of the second valve core, the second valve core is inserted into the step countersunk hole of the second amplitude-changing rod, it is axially movable and radially fixed, and the second valve core cannot rotate in the second amplitude-changing rod; an annular baffle is provided on the outer sleeve of the second valve core, which is fixed to the coarse diameter end of the step countersunk hole of the second amplitude-changing rod, and the annular baffle protrudes from the step of the step countersunk hole, and a spring is installed between the part of the annular baffle protruding from the step and the rectangular protrusion.

[0012] The water droplet forming device C includes an ultrasonic transducer b, which is connected to an ultrasonic generator b; an axial through hole is provided in the middle of the ultrasonic transducer b, which includes a third front end cover and a third rear end cover connected by bolts, a third piezoelectric ceramic is installed between the two, and a copper pole piece is installed between every two pieces of the third piezoelectric ceramics, and the third rear end cover is fixedly connected to a third amplitude rod; the third front end cover is connected to the high-pressure nozzle.

[0013] Variable angle nozzles are a series of nozzles with different bending angles or nozzles with adjustable angles.

[0014] Another technical solution adopted by the present invention is a water drop shot peening method, which uses the above-mentioned water drop shot peening device and is specifically implemented according to the following steps:

[0015] Step 1: Fix the workpiece on the workpiece moving table and adjust the parameters of the injection system according to the processing requirements of different materials;

[0016] Step 2: Start a high-pressure water pump connected to the high-pressure nozzle, and water flows through the high-pressure nozzle into a water droplet forming device to form a stable and continuous string of water droplets; wherein the frequency range of the water droplet forming device is 50Hz-1000Hz or 20kHz-40kHz;

[0017] Step 3: Control the workpiece moving table to make the workpiece reach the predetermined position. Then, according to the workpiece processing requirements, move the robot arm along the predetermined trajectory to ensure that the water droplets always act on the workpiece surface at the set angle and distance to achieve water drop shot peening. If the inner surface of the workpiece is to be processed, variable angle nozzles with different bending angles can be used to ensure that the water droplets can reach the inner surface of the workpiece.

[0018] Step 4: During the machining process, the spray pressure, time, and frequency of water droplets are monitored in real time to ensure that the water droplets are sprayed onto the workpiece surface at high speed and evenly;

[0019] Step 5: After the processing is completed, upload the water droplet velocity and shape data collected by the high-speed camera, and optimize the injection parameters based on the performance test results of the workpiece after processing.

[0020] Another technical solution of the present invention is also characterized in that:

[0021] In step 3, the spraying distance is 10-50 cm, and the water droplet spraying angle is 30°-90°.

[0022] The beneficial effects of the present invention are:

[0023] (1) The method of the present invention uses water droplets as the processing medium. The high-speed water droplets impact the inner and outer surfaces of the metal material, causing the impacted surface and the underlying metal material to undergo elastic-plastic deformation, thereby forming a strengthening layer and a residual compressive stress layer of a certain thickness to improve the fatigue strength of the part, or to control the residual stress field to produce the desired deformation of the part. Because water droplets have higher kinetic energy and impact pressure than water flow, shot peening has a better effect under the same water pressure;

[0024] (2) The method of the present invention uses water droplets as the processing medium, and no foreign material remains on the processing surface, which can ensure that the processing surface material is pure and pollution-free; water can be recycled, and the recycling cost is low, which reduces the processing cost and makes the processing process green and environmentally friendly; when the inner surface of the part cavity is processed by water droplets, the water can flow out smoothly to avoid clogging the inner cavity; when the part cavity is processed with a variable angle nozzle at different angles, the water droplets can reach all surfaces of the inner cavity, which can ensure the processing quality of the inner surface; the higher impact energy of the water droplets can reduce the water pressure requirement, thereby improving the safety of the equipment and reducing the equipment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of the water drop shot peening processing device of the present invention;

[0026] Figure 2 Schematic diagram of the structure of the water droplet forming device A in the shot peening device of the present invention;

[0027] Figure 3 1 is a front view of a water droplet forming device A in a shot peening device according to the present invention;

[0028] Figure 4 yes Figure 3 Schematic diagram of the cross-sectional structure along the middle BB direction;

[0029] Figure 5 yes Figure 3 Schematic diagram of the cross-sectional structure along the AA direction;

[0030] Figure 6 Schematic diagram of the structure of the water droplet forming device B in the shot peening device of the present invention;

[0031] Figure 7 1 is a front view of a water droplet forming device B in a shot peening device according to the present invention;

[0032] Figure 8 yes Figure 7 Schematic diagram of the local cross-section structure in the A direction;

[0033] Figure 9 yes Figure 8 Enlarged view of point C in the middle;

[0034] Figure 10 yes Figure 7 Schematic diagram of the local cross-section structure along the middle BB direction;

[0035] Figure 11 Schematic diagram of the structure of the water droplet forming device C in the shot peening device of the present invention;

[0036] Figure 12 2 is a cross-sectional view of a water droplet forming device C in a shot peening device according to the present invention;

[0037] Figure 13 It is a schematic structural diagram of various fixed-angle variable-angle nozzles in the shot peening device of the present invention;

[0038] Figure 14 It is a schematic structural diagram of an adjustable angle nozzle in the shot peening device of the present invention;

[0039] Figure 15 This is a comparison of the impact forces generated by a water droplet train and a water jet.

[0040] In the figure, 1. High-pressure nozzle, 2. Water droplet forming device, 3. High-speed camera, 4. Computer, 5. Workpiece moving platform, 6. Robot arm;

[0041] 11. First valve body, 12. First valve core, 13. First flange, 14. Connecting rod, 15. Eccentric wheel, 16. Motor, 17. Motor support plate;

[0042] 21. Second valve body, 22. Second flange, 23. Second valve core, 24. Spring, 25. Second amplitude rod, 26. Second rear end cover, 27. Second piezoelectric ceramic, 28. Second front end cover, 29. Second bolt, 210. Baffle;

[0043] 31. Third front end cover, 32. Copper pole piece, 33. Third bolt, 34. Third piezoelectric ceramic, 35. Third rear end cover, 36. Third amplitude rod. DETAILED DESCRIPTION

[0044] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] Example 1

[0046] The water drop shot blasting processing device of the present invention has a structure as follows Figure 1 As shown, the robot arm 6 includes a multi-degree-of-freedom robot arm 6, the end of which is connected to a high-pressure nozzle 1 via a flange. The outlet of the high-pressure nozzle 1 is also connected to a water droplet forming device 2 via a flange. The outlet of the water droplet forming device 2 is connected to a variable-angle nozzle. The function of the water droplet forming device 2 is to convert the water flow into a continuous stream of water droplets. Water enters the water droplet forming device 2 from the high-pressure nozzle 1, forms water droplets, and is then ejected from the variable-angle nozzle. The robot arm 6 is used to adjust the position and direction of the variable-angle nozzle, thereby adjusting the position and angle of the water droplet ejection, achieving a variety of motion trajectories. A high-speed camera 3 is located near the water droplet forming device 2 to capture the water droplets ejected by the water droplet forming device 2. The computer 4 connected to the camera 3 then analyzes the droplet shape, running speed, and other data. A workpiece moving platform 5 is located below the water droplet forming device 2 to place the workpiece to be processed. The workpiece moving platform 5 is mounted on two parallel slide rails for easy back-and-forth movement. The workpiece moving platform 5 is also connected to the computer 4 for easy control of the workpiece moving platform 5.

[0047] The water droplet forming device 2 of the present invention can have the following three structures: water droplet forming device A, water droplet forming device B, and water droplet forming device C, which respectively use the truncation method, the lateral perturbation method, and the longitudinal perturbation method to generate water droplets. The structures of the three devices are as follows:

[0048] Example 2

[0049] On the basis of Example 1, the water droplet forming device A uses the truncation method to form water droplets, that is, the frequency of the high-pressure fluid outflow is controlled by the truncation device to generate water droplet strings with different frequencies. Its structure is as follows: Figure 2-Figure 5 As shown, the device comprises a first valve body 11, a first valve core 12, a first flange 13, a connecting rod 14, an eccentric 15, a motor 16, and a motor support plate 17. In the structural design of this device, the motor 16 is mounted on the motor support plate 17, while the eccentric 15 is mounted on the output shaft of the motor 16. The eccentric 15 is connected to the connecting rod 14, which is connected to the first valve core 12. The first valve core 12 extends into the high-pressure fluid flow channel in the first valve body 11. The connecting rod 14, eccentric 15, motor 16, and motor support plate 17 are mounted in a housing, which is connected to the first valve body 11 via the first flange 13. The high-pressure nozzle 1 is connected to the first valve body 11 through the flange of the first valve body 11. Water enters the first valve body 11 through the high-pressure nozzle 1. At the same time, the rotation of the motor 16 drives the eccentric wheel 15 to rotate. The rotation of the eccentric wheel 15 drives the connecting rod 14 to move, and then drives the first valve core 12 to move, converting the rotational motion of the motor 16 into the reciprocating motion of the first valve core 12. The reciprocating motion has a cutting effect on the water flow flowing through the flow channel of the first valve body 11, so that the variable-angle nozzle at the outlet of the first valve body 11 sprays a stable string of water droplets.

[0050] Example 3

[0051] On the basis of Example 1, the water droplet forming device B uses the lateral disturbance method to form water droplets, that is, by introducing lateral disturbance into the fluid ejected from the high-pressure nozzle 1, the water ejected from the variable-angle nozzle becomes a fluctuating water droplet string. Its structure is as follows: Figures 6-10 As shown, it includes a second valve body 21, a second flange 22, a second valve core 23, a spring 24, a second horn 25, a second rear end cover 26, a second piezoelectric ceramic 27, a second front end cover 28, a second bolt 29, and a baffle 210. In the structural design of the device, the second front end cover 28, the second piezoelectric ceramic 27, the second rear end cover 26, and the second horn 25 are connected together by the second bolt 29 to form an ultrasonic transducer a.

[0052] The end of the second amplitude-changing rod 25 is connected to the second valve core 23. After the connection, the second valve core 23 is fixed radially and can move axially within a certain range. An axial step countersunk hole is provided at the center of the end of the second amplitude-changing rod 25. The coarse diameter end of the step countersunk hole is on the outside and the fine diameter end is on the inside. The diameter of the fine diameter end is equal to the diameter of the second valve core 23. The inner wall of the fine diameter end hole is provided with two opposite rectangular grooves. The depth of the grooves is less than the radius difference between the coarse and fine diameter end holes, that is, the bottom of the grooves does not reach the inner wall of the coarse diameter end hole. Two rectangular protrusions of the same size and corresponding position as the rectangular grooves are provided on the outer side wall of the end of the second valve core 23. The second valve core 23 is inserted into the step countersunk hole of the second amplitude-changing rod 25. It can move axially and is fixed radially. Due to the existence of the rectangular grooves and the rectangular protrusions, the second valve core 23 cannot rotate in the second amplitude-changing rod 25. Figure 8 、 Figure 9 、 Figure 10 As shown, an annular baffle 210 is provided on the outer sleeve of the second valve core 23, which is fixed to the coarse diameter end of the step countersunk hole of the second horn 25, and the annular baffle 210 protrudes from the step of the step countersunk hole. A spring 24 is installed between the part of the annular baffle 210 protruding from the step and the rectangular protrusion, so that the annular baffle 210 limits the movement of the second valve core 23 within a certain radial range, and the spring 24 has a buffering effect on the vibration of the second valve core 23 caused by the ultrasonic transducer a.

[0053] The second horn 25 is connected to the second valve body 21 via the second flange 22. During operation, the high-pressure nozzle 1 is connected to the second valve body 21 via the flange of the second valve body 21, and water enters the second valve body 21 through the high-pressure nozzle 1. Furthermore, the ultrasonic transducer a in the device is connected to the ultrasonic generator a, which generates a high-frequency electrical signal. The ultrasonic transducer a converts the electrical frequency signal into mechanical vibrations of a specific amplitude. At this vibration frequency, the ultrasonic transducer a resonates with the second valve core 23, causing the second valve core 23 to generate a specific frequency disturbance in the water flow within the flow channel, causing the water ejected from the variable-angle nozzle to form a fluctuating string of water droplets.

[0054] Example 4

[0055] Based on Example 1, the water droplet forming device C uses the longitudinal perturbation method to generate water droplets. That is, by introducing longitudinal perturbations into the fluid ejected from the high-pressure nozzle 1, the water ejected from the variable-angle nozzle is formed into a string of water droplets. The longitudinal perturbation device is mainly an ultrasonic vibration device with a through hole in the middle, including an ultrasonic generator b and an ultrasonic transducer b. Its structure is as follows: Figure 11 、 Figure 12As shown, the ultrasonic transducer b comprises a third front cover 31, a copper pole piece 32, a third bolt 33, a third piezoelectric ceramic 34, a third rear cover 35, and a third horn 36. In the structural design of this device, the third piezoelectric ceramic 34 is installed between the third front cover 31 and the third rear cover 35. A copper pole piece 32 is installed between every two third piezoelectric ceramics, and they are compressed by third bolts 33. The third rear cover 35 and the third horn 36 are connected by screws, forming an ultrasonic transducer b. This ultrasonic transducer b is connected to an ultrasonic generator b, which generates a high-frequency electrical signal. The ultrasonic transducer b converts the electrical frequency signal into mechanical vibrations of a specific amplitude. The third front cover 31 of the ultrasonic transducer b is connected to the high-pressure nozzle 1. Water flowing out of the high-pressure nozzle 1 enters the through-hole in the center of the ultrasonic transducer b. The mechanical vibration of the ultrasonic transducer b causes additional pressure fluctuations (standing waves) in the water flow of the high-pressure nozzle 1, causing the water ejected from the variable-angle nozzle to form a fluctuating train of droplets.

[0056] Example 5

[0057] On the basis of Example 1, the structure of the variable angle nozzle in the water drop shot blasting device of the present invention is as follows Figure 13 、 Figure 14 As shown, it can be a fixed angle nozzle or an adjustable angle nozzle. Figure 13 As shown in FIG, the bending angle of the fixed angle nozzle is fixed, but it can be a series of nozzles with different bending angles, so that the water flow or water droplets sprayed from the nozzle move in a specific direction. Figure 14 As shown, the adjustable angle nozzle is adjustable and can be adjusted using a ball valve. The high-pressure nozzle 1 is fixed to a robotic arm 6. The droplet-forming device 2 and the variable-angle nozzle are fixedly connected to the high-pressure nozzle 1. The robotic arm 6 moves the variable-angle nozzle along a predetermined trajectory, ensuring the nozzle's position and initial spray direction. The nozzle's bend angle controls the spray angle, ensuring that the water droplets reach the processing location.

[0058] Example 6

[0059] The water drop shot blasting method of the present invention is specifically implemented according to the following steps:

[0060] Step 1: Fix the workpiece on the workpiece moving table 5 to ensure that it remains stable during the processing. According to the processing requirements of different materials, adjust various parameters of the injection system, such as injection pressure, time, injection angle, etc.

[0061] Step 2: Start the high-pressure water pump, and water flows through high-pressure nozzle 1 into droplet-forming device 2, forming stable, continuous droplets. The droplet frequency is controlled by droplet-forming device 2, which has a frequency range of 50Hz-1000Hz or 20kHz-40kHz. Low frequencies can be achieved by the cutoff device in droplet-forming device A, while high frequencies can be achieved by high-frequency perturbations of the water ejected from the variable-angle nozzle using the other two droplet-forming devices.

[0062] In step 3, the workpiece moving platform 5 is controlled to move the workpiece to the predetermined position. The robot arm 6 then moves along a predetermined trajectory based on the workpiece processing requirements, ensuring that the water droplets always strike the workpiece surface at the set angle and distance, thereby achieving water droplet shot peening. If the inner surface of the workpiece is to be processed, a variable angle nozzle with different bend angles can be used to ensure that the water droplets reach the inner surface of the workpiece.

[0063] The spray distance is 10-50cm, with a range of 10-20cm for small precision parts and 20-50cm for larger workpieces. The spray angle ranges from 30° to 90°, adjustable using the robot arm 6 and the variable-angle nozzle. Vertical spraying maximizes the impact of the droplet stream, achieving optimal surface enhancement. For complex workpieces, the angle can be adjusted to ensure complete coverage.

[0064] Step 4: During the processing, the injection pressure, time and frequency of water droplets are monitored in real time to ensure that the water droplets are sprayed onto the workpiece surface at high speed and evenly to achieve the ideal processing effect.

[0065] Step 5: After processing is completed, upload the data such as water droplet velocity and shape collected by the high-speed camera 3. Based on the test results of the workpiece surface morphology, residual stress and hardness, the injection parameters are optimized to ensure the stability and reliability of the next round of processing.

[0066] The shot peening method of the present invention uses water droplets for shot peening. Compared with the existing commonly used water jet shot peening method, the water droplets of the method of the present invention have the following advantages:

[0067] (1) The flow shapes of water droplets and water jets are different

[0068] The water droplets used in the present method are approximately spherical or elliptical droplet strings, while water jets are elongated, tubular, or conical streams. In comparison, water droplets can provide higher kinetic energy during the brief impact, resulting in higher impact power and greater elastoplastic deformation of the material. Furthermore, the discrete nature of water droplets makes it easier to control the processing position during water droplet shot peening, avoiding impact on non-processing areas during nozzle movement.

[0069] (2) The peak impact force generated by water jets and water droplets is different:

[0070] For water jets: Based on the conservation of momentum and the control volume method, the expression for the jet impact force F is obtained:

[0071]

[0072] Where: ρ is the liquid density, v0 is the jet velocity relative to the nozzle, and d0 is the jet diameter.

[0073] For a string of water drops: the impact force of a single water drop is extended to the entire string of water drops, and the total impact force is calculated by accumulating the impact force of each water drop.

[0074] The impact force of a single water droplet describes the change of force over time when the droplet impacts. The calculation equation is as follows:

[0075]

[0076] Where: is dimensionless time, is the dimensionless force, v is the droplet velocity, and D is the droplet diameter.

[0077] The total impact force is the sum of all individual drop impact forces and can be expressed as:

[0078]

[0079] Where: is the impact force of a single water drop, is the impact time of the nth drop, and f is the frequency.

[0080] The droplet impact force normalized by the above spray parameters , the expression is:

[0081]

[0082] From the above expression, the change of the impact force of the water jet and the water droplet string can be plotted as follows: Figure 15 As shown in the figure, the solid line is the impact force of the water droplet train, and the dotted line is the impact force of the water jet. It can be seen that under the same water pressure and nozzle size conditions, due to the conservation of momentum, the normal peak impact force of the water droplet train when perpendicular to the surface is about three times that of the water jet. Therefore, the water droplet train can more effectively cause elastic-plastic deformation of the target material to improve shot peening performance, or better clean and treat the surface of the part.

Claims

1. Water drop shot blasting device, characterized in that, The invention comprises a multi-degree-of-freedom robot arm (6), wherein a high-pressure nozzle (1) is fixedly connected to the end of the robot arm (6), a water drop forming device (2) is fixedly connected to the outlet end of the high-pressure nozzle (1), a variable-angle nozzle is connected to the outlet of the water drop forming device (2), and the function of the water drop forming device (2) is to convert water from the high-pressure nozzle (1) into a string of water droplets and spray them from the variable-angle nozzle; a high-speed camera (3) is arranged near the water drop forming device (2) for photographing water droplets sprayed by the water drop forming device (2), a workpiece moving platform (5) is arranged below the water drop forming device (2) for placing a workpiece to be processed, and the workpiece moving platform (5) is installed on two parallel slide rails; the high-speed camera (3) and the workpiece moving platform (5) are both connected to a computer (4), and the computer (4) is used to store and analyze the shape and running speed data of the water droplets photographed by the high-speed camera (3), and to control the movement of the workpiece moving platform (5); The water droplet forming device (2) comprises a second valve body (21) and a second valve core (23), the second valve core (23) extends into a high-pressure fluid flow channel in the second valve body (21), the other end of the second valve core (23) is connected to an ultrasonic transducer a, and the second valve body (21) and the ultrasonic transducer a are connected via a second flange (22); the high-pressure nozzle (1) is connected to the second valve body (21) via the flange of the second valve body (21); the ultrasonic transducer a is connected to an ultrasonic generator a; The ultrasonic transducer a comprises a second front end cover (28), a second piezoelectric ceramic (27), a second rear end cover (26) and a second amplitude rod (25) which are connected in sequence, and the above four components are connected together by a second bolt (29); the second amplitude rod (25) is connected to the second valve body (21) through a second flange (22), and the end of the second amplitude rod (25) is also connected to the second valve core (23); after the connection, the second valve core (23) is fixed in the radial direction and movable in the axial direction; An axial step countersunk hole is provided at the center of the end of the second amplitude-changing rod (25), wherein the large diameter end of the step countersunk hole is on the outside and the small diameter end is on the inside, the diameter of the small diameter end is equal to the diameter of the second valve core (23), and the inner wall of the small diameter end hole is provided with two opposite rectangular grooves, the depth of the grooves being less than the radius difference between the large diameter end hole and the small diameter end hole; two rectangular protrusions having the same size as the rectangular grooves and corresponding positions are provided on the outer wall of the end of the second valve core (23); the second valve core (23) is inserted into the step countersunk hole of the second amplitude-changing rod (25), is movable in the axial direction and fixed in the radial direction, and the second valve core (23) cannot rotate in the second amplitude-changing rod (25); an annular baffle (210) is provided on the outer sleeve of the second valve core (23), the annular baffle (210) is fixed to the large diameter end of the step countersunk hole of the second amplitude-changing rod (25), and the annular baffle (210) protrudes from the step of the step countersunk hole, and a spring (24) is installed between the portion of the annular baffle (210) protruding from the step and the rectangular protrusion.

2. The water drop shot blasting device according to claim 1, characterized in that: The variable angle nozzle is a series of nozzles with different bending angles or a nozzle with adjustable angle.

3. The water drop shot peening method is characterized in that: The water drop shot blasting device according to any one of claims 1-2 is used, and is specifically implemented according to the following steps: Step 1, fix the workpiece on the workpiece moving table (5), and adjust various parameters of the injection device according to the processing requirements of different materials; Step 2, starting a high-pressure water pump connected to the high-pressure nozzle (1), so that water flows through the high-pressure nozzle (1) into the water droplet forming device (2), forming a stable and continuous string of water droplets; wherein the frequency range of the water droplet forming device (2) is 50Hz-1000Hz or 20kHz-40kHz; Step 3, controlling the workpiece moving platform (5) to make the workpiece reach the predetermined position, and then moving the robot arm (6) along the predetermined trajectory according to the workpiece processing requirements, ensuring that the water droplet flow always acts on the workpiece surface at the set angle and distance, so as to realize the water drop shot peening process; if the inner surface of the workpiece is to be processed, a variable angle nozzle with different bending angles can be used so that the water droplets can reach the inner surface of the workpiece; Step 4: During the machining process, the spray pressure, time, and frequency of water droplets are monitored in real time to ensure that the water droplets are sprayed onto the workpiece surface at high speed and evenly; Step 5: After the processing is completed, the water droplet velocity and shape data collected by the high-speed camera (3) are uploaded, and the injection parameters are optimized based on the performance test results of the workpiece after processing.

4. The water drop shot peening method according to claim 3, characterized in that: In step 3, the spraying distance is 10-50 cm, and the water droplet spraying angle is 30°-90°.

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