Water drop shot blasting processing device and processing method

Abstract

The invention discloses a water drop shot blasting device which comprises a multi-degree-of-freedom robot arm, a high-pressure nozzle is fixedly connected to the tail end of the robot arm, a water drop forming device is fixedly connected to the outlet end of the high-pressure nozzle, and a variable-angle nozzle is connected to a water outlet of the water drop forming device. The water drop forming device is used for forming water of the high-pressure nozzle into a water drop string and spraying the water drop string from the variable-angle nozzle; a high-speed camera is arranged near the water drop forming device and used for shooting water drops sprayed by the water drop forming device, a workpiece moving table is arranged below the water drop forming device and used for placing workpieces to be machined, and the workpiece moving table is installed on two parallel sliding rails; and the high-speed camera and the workpiece moving table are connected to a computer. The invention further discloses a method for carrying out shot blasting processing by using the device. The method utilizes the water drop string to perform shot blasting, and has the characteristics of capability of processing the inner and outer surfaces of the workpiece, low cost and good processing performance.

Description

Technical Field

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

[0002] Shot peening is a process for strengthening the surface of metal parts and forming metal sheets. There are different process forms such as shot peening, laser peening, ultrasonic peening, cavitation water peening, and water jet peening. The shot peening process drives the projectiles (such as steel shots, cast iron shots, glass shots, etc.) to impact the surface of the parts through air pressure or impeller centrifugal force to achieve the purpose of strengthening or forming the parts. Laser peening uses high-power pulsed laser beams to induce shock waves to strengthen or form parts. Ultrasonic peening uses ultrasonic transducers and horns to drive the striker to impact the surface of the parts at high speed, or uses ultrasonic transducers and horns to drive the projectiles in the inner cavity of the parts to move at a high speed at the opening position of the inner cavity of the parts to impact the inner surface of the parts, so as to achieve the purpose of strengthening or forming the parts. Cavitation water peening uses the impact force generated by the collapse of cavitation bubbles in high-speed high-pressure water jets to strengthen the surface of parts. Water jet peening uses high-pressure water flow to directly impact the surface of parts, or uses mixed abrasive particles in high-pressure water jets to impact the surface of parts, so as to achieve the purpose of strengthening or forming parts.

[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 shot 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 water drop string to perform 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 peening using the above device.

[0006] The technical solution adopted by the present invention is a water droplet shot peening processing device, comprising a multi-degree-of-freedom robot arm, a high-pressure nozzle is fixedly connected to the end of the robot arm, a water droplet forming device is fixedly connected to the outlet end of the high-pressure nozzle, a variable-angle nozzle is connected to the water outlet of the water droplet forming device, and the function of the water droplet 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 droplet forming device for photographing the water droplets sprayed by the water droplet forming device, a workpiece moving platform is arranged below the water droplet 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: 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. 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, the eccentric wheel, the motor and the motor support plate are all installed in a 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.

[0008] 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 an 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 an ultrasonic generator a.

[0009] Ultrasonic transducer a includes a second front end cover, a second piezoelectric ceramic, a second rear end cover and a second amplitude rod which are connected in sequence, and 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 the connection, the second valve core is radially fixed and axially movable.

[0010] 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 being equal to the diameter of the second valve core, and the inner wall of the fine diameter end hole being provided with two opposite rectangular grooves, the depth of the grooves being less than the radius difference between the coarse diameter and fine diameter end holes; two rectangular protrusions of the same size and corresponding positions as the rectangular grooves are provided on the outer side 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, the annular baffle 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.

[0011] The water droplet forming device C includes an ultrasonic transducer b, which is connected to an ultrasonic generator b; an axial through hole is arranged 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 transformer; the third front end cover is connected to the high-pressure nozzle.

[0012] The variable angle nozzle is a series of nozzles with different bending angles or nozzles with adjustable angles.

[0013] 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: Step 1, fix the workpiece on the workpiece moving table, and adjust various parameters of the injection system according to the processing requirements of different materials; Step 2, starting a high-pressure water pump connected to the high-pressure nozzle, and water flows into a water droplet forming device through the high-pressure nozzle 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; Step 3, control the workpiece moving table to make the workpiece reach the predetermined position, and then according to the workpiece processing requirements, make the robot arm move along the predetermined trajectory to ensure that the water droplet flow always acts on the workpiece surface at the set angle and distance to achieve water droplet shot peening processing; 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 processing, the spray pressure, time and water drop frequency 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, upload the water droplet speed 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.

[0014] Another technical solution of the present invention is also characterized in that: In step 3, the spraying distance is 10-50 cm, and the water droplet spraying angle is 30°-90°.

[0015] The beneficial effects of the present invention are: (1) The method of the present invention uses water droplets as processing media. 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 parts, or to control the residual stress field to produce the desired deformation of the parts. Since water droplets have higher kinetic energy and impact pressure than water flow, shot peening has a better effect under the same water pressure; (2) The method of the present invention uses water droplets as processing media, and no foreign materials remain 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; using water droplets to process the inner surface of the part cavity, the water can flow out smoothly to avoid clogging the inner cavity; using variable angle nozzles at different angles to process the part cavity, the water droplets can reach all surfaces of the inner cavity, which can ensure the processing quality of the inner surface; using the higher impact energy of the water droplets, the water pressure requirement can be reduced, thereby improving the safety of the equipment and reducing the equipment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the water drop shot peening processing device of the present invention; Figure 2 Schematic diagram of the structure of a water droplet forming device A in the shot peening device of the present invention; Figure 3 It is a front view of a water drop forming device A in the shot peening device of the present invention; Figure 4 yes Figure 3 Schematic diagram of the cross-sectional structure along the BB direction; Figure 5 yes Figure 3 Schematic diagram of the cross-sectional structure along the AA direction; Figure 6 It is a schematic structural diagram of a water droplet forming device B in a shot peening device of the present invention; Figure 7 It is a front view of a water drop forming device B in the shot peening device of the present invention; Figure 8 yes Figure 7 Schematic diagram of the local cross-section structure in the A direction; Fig. 9 yes Figure 8 Enlarged view of point C in the middle; Fig.10 yes Figure 7 Schematic diagram of the local cross-section structure along the BB direction; Fig.11 Schematic diagram of the structure of the water droplet forming device C in the shot peening device of the present invention; Fig.12 is a cross-sectional view of a water droplet forming device C in the shot peening device of the present invention; Fig.13 It is a schematic diagram of the structure of various fixed-angle variable-angle nozzles in the shot peening device of the present invention; Fig.14 It is a schematic structural diagram of an adjustable angle variable angle nozzle in the shot peening device of the present invention; Fig.15 This is a comparison chart of the impact force generated by a water droplet string and a water jet.

[0017] In the figure, 1. high-pressure nozzle, 2. water droplet forming device, 3. high-speed camera, 4. computer, 5. workpiece moving table, 6. robot arm; 11. first valve body, 12. first valve core, 13. first flange, 14. connecting rod, 15. eccentric wheel, 16. motor, 17. motor support plate; 21. second valve body, 22. second flange, 23. second valve core, 24. spring, 25. second amplitude changing rod, 26. second rear end cover, 27. second piezoelectric ceramic, 28. second front end cover, 29. second bolt, 210. baffle; 31. third front end cover, 32. copper pole piece, 33. third bolt, 34. third piezoelectric ceramic, 35. third rear end cover, 36. third amplitude transformer. DETAILED DESCRIPTION

[0018] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Example 1 The water drop shot peening processing device of the present invention has a structure as follows Figure 1 As shown, it includes a multi-degree-of-freedom robot arm 6, the end of the robot arm 6 is connected to a high-pressure nozzle 1 through a flange, the outlet end of the high-pressure nozzle 1 is connected to a water drop forming device 2 through a flange, and the outlet of the water drop forming device 2 is connected to a variable angle nozzle. The function of the water drop forming device 2 is to change the water flow into a continuous string of water droplets. The water enters the water drop forming device 2 from the high-pressure nozzle 1, and is sprayed from the variable angle nozzle after forming water droplets. 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 spraying to achieve a variety of motion trajectories. A high-speed camera 3 is arranged near the water drop forming device 2, which is used to shoot the water droplets sprayed by the water drop forming device 2, and then the shape, running speed and other data of the water droplets are analyzed through the computer 4 connected thereto. A workpiece moving platform 5 is arranged below the water drop forming device 2, which is used to place the workpiece to be processed. The workpiece moving platform 5 is installed on two parallel slide rails for convenient back and forth movement. The workpiece moving platform 5 is also connected to the computer 4 for convenient control of the workpiece moving platform 5.

[0020] The water droplet forming device 2 of the present invention can be of the following three structures. The three devices are respectively a water droplet forming device A, a water droplet forming device B and a water droplet forming device C, which respectively use a truncation method, a lateral disturbance method and a longitudinal disturbance method to generate water droplets. The structures of the three devices are specifically as follows: Example 2 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 5As shown, it includes a first valve body 11, a first valve core 12, a first flange 13, a connecting rod 14, an eccentric wheel 15, a motor 16 and a motor support plate 17. In the structural design of the device, the motor 16 is mounted on the motor support plate 17, and the eccentric wheel 15 is mounted on the output shaft of the motor 16. The eccentric wheel 15 is connected to the connecting rod 14, and the connecting rod 14 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, the eccentric wheel 15, the motor 16 and the motor support plate 17 are installed in the housing, and the housing is connected to the first valve body 11 through 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, and 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, and the rotation of the eccentric wheel 15 drives the connecting rod 14 to move, and then drives the first valve core 12 to move, and converts 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.

[0021] Example 3 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 sprayed from the high-pressure nozzle 1, the water sprayed from the variable-angle nozzle becomes a fluctuating water droplet string. Its structure is as follows: Figure 6-Figure 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.

[0022] 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 groove is less than the radius difference between the coarse diameter and fine diameter end holes, that is, the bottom of the groove 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 , Fig. 9 , Fig.10As shown, an annular baffle plate 210 is provided on the outer sleeve of the second valve core 23, and the annular baffle plate 210 is fixed to the coarse diameter end of the step countersunk hole of the second amplitude changing rod 25, and the annular baffle plate 210 protrudes from the step of the step countersunk hole, and a spring 24 is installed between the protruding step portion of the annular baffle plate 210 and the rectangular protrusion, so that the annular baffle plate 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.

[0023] The second horn 25 is connected to the second valve body 21 through the second flange 22. When in use, the high-pressure nozzle 1 is connected to the second valve body 21 through the flange of the second valve body 21, and water enters the second valve body 21 through the high-pressure nozzle 1. In addition, the ultrasonic transducer a in the device is connected to the ultrasonic generator a, and a high-frequency electrical signal is generated by the ultrasonic generator a. The ultrasonic transducer a converts the electrical frequency signal into a mechanical vibration of a specific amplitude. At this vibration frequency, the ultrasonic transducer a resonates with the second valve core 23, and then the second valve core 23 generates a disturbance of a specific frequency on the water flow in the flow channel, so that the water sprayed from the variable angle nozzle becomes a fluctuating string of water droplets.

[0024] Example 4 On the basis of Example 1, the water droplet forming device C uses the longitudinal disturbance method to generate water droplets, that is, by introducing longitudinal disturbance into the fluid sprayed from the high-pressure nozzle 1, the water sprayed from the variable-angle nozzle is formed into a string of water droplets. The longitudinal disturbance device is mainly an ultrasonic vibration device with a through hole in the middle, including an ultrasonic generator b and an ultrasonic transducer b, and its structure is as follows: Fig.11 , Fig.12 As shown, it includes a third front end cover 31, a copper pole piece 32, a third bolt 33, a third piezoelectric ceramic 34, a third rear end cover 35 and a third horn 36. In the structural design of the device, a third piezoelectric ceramic 34 is installed between the third front end cover 31 and the third rear end cover 35, and a copper pole piece 32 is installed between every two third piezoelectric ceramics, and they are compressed by the third bolt 33, and the third rear end cover 35 and the third horn 36 are connected by screws to form an ultrasonic transducer b. The ultrasonic transducer b is connected to the ultrasonic generator b, and a high-frequency electrical signal is generated by the ultrasonic generator b. The ultrasonic transducer b converts the electrical frequency signal into a mechanical vibration of a specific amplitude. The third front end cover 31 of the ultrasonic transducer b is connected to the high-pressure nozzle 1, and the water flowing out of the high-pressure nozzle 1 enters the through hole in the middle of the ultrasonic transducer b. The mechanical vibration of the ultrasonic transducer b causes the water flow in the high-pressure nozzle 1 to generate additional pressure fluctuations (standing waves), so that the water sprayed from the variable angle nozzle forms a fluctuating water droplet string.

[0025] Example 5 Based on Example 1, the structure of the variable angle nozzle in the water drop shot peening processing device of the present invention is as follows: Fig.13 , Fig.14As shown, it can be a fixed angle nozzle or an adjustable angle nozzle. Fig.13 As shown in the figure, 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. Fig.14 As shown, the angle of the adjustable angle nozzle is adjustable, and the nozzle angle can be adjusted by a ball valve. The high-pressure nozzle 1 is fixed on the robot arm 6, and the water droplet forming device 2 and the variable angle nozzle are fixedly connected to the high-pressure nozzle 1. The robot arm 6 is used to move the variable angle nozzle along a predetermined trajectory to ensure the position and initial spray direction of the variable angle nozzle; and then the spray angle is controlled by the bending angle of the variable angle nozzle to make the water droplets reach the processing position.

[0026] Example 6 The water drop shot peening method of the present invention is specifically implemented according to the following steps: Step 1, fix the workpiece on the workpiece moving table 5 to ensure that it remains stable during the processing, and adjust various parameters of the injection system, such as injection pressure, time, injection angle, etc., according to the processing requirements of different materials.

[0027] Step 2, start the high-pressure water pump, and water flows into the water droplet forming device 2 through the high-pressure nozzle 1 to form stable and continuous water droplets. The water droplet frequency is controlled by the water droplet forming device 2, and the frequency range of the water droplet forming device 2 is 50Hz-1000Hz or 20kHz-40kHz. The low frequency can be achieved by the cutoff device in the water droplet forming device A, and the high frequency can be achieved by the other two water droplet forming devices to perform high-frequency disturbance on the water sprayed from the variable angle nozzle.

[0028] Step 3, control the workpiece moving platform 5 to make the workpiece reach the predetermined position, and then according to the workpiece processing requirements, make the robot arm 6 move along the predetermined trajectory to ensure that the water droplet flow always acts on the workpiece surface at the set angle and distance to achieve water droplet shot peening. 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.

[0029] The spray distance is 10-50cm. The spray distance for small precision parts can be set to 10-20cm, and the larger workpiece can be set to 20-50cm. The water droplet spray angle is 30°-90°, which can be adjusted by the robot arm 6 and the variable angle nozzle. When spraying vertically, the impact force of the water droplet string is the largest, which can better achieve surface strengthening. For some workpieces with complex shapes, the angle can be adjusted to ensure full coverage.

[0030] Step 4: During the processing, the injection pressure, time and water drop frequency 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.

[0031] Step 5: After the processing is completed, upload the data such as the water droplet velocity and shape collected by the high-speed camera 3. According to the test results such as 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.

[0032] 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: (1) The flow shapes of water droplets and water jets are different The water droplets used in the method of the present invention are approximately spherical or elliptical water droplet strings, while the water jet is a slender tubular or conical water flow. In comparison, the water droplets can provide higher kinetic energy during a short impact process, that is, the impact power is higher, and it is easier to cause elastic-plastic deformation of the material. In addition, the discrete characteristics of the water droplets make it easier to control the processing position of the water droplet shot peening process, avoiding the impact of the non-processing area in the middle during the movement of the nozzle.

[0033] (2) The peak impact force generated by water jets and water droplets is different: For water jet: Based on the conservation of momentum and the control volume method, the expression of the jet impact force F is obtained:

[0034] Where: ρ is the liquid density, v0 is the jet velocity relative to the nozzle, and d0 is the jet diameter.

[0035] 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.

[0036] 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:

[0037] Where: is the dimensionless time, is the dimensionless force, v is the droplet velocity, and D is the droplet diameter.

[0038] The total impact force is the sum of all individual drop impact forces and can be expressed as:

[0039] Where: is the impact force of a single water drop, is the impact time of the nth drop, and f is the frequency.

[0040] The droplet impact force normalized by the above spray parameters , the expression is:

[0041] From the above expressions, the changes in the impact force of the water jet and the water droplet string can be plotted as follows: Fig.15 As shown, the solid line is the impact force of the water droplet string, 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 string when it vertically impacts the surface is about 3 times that of the water jet. Therefore, the water droplet string can more effectively cause elastic-plastic deformation of the target material to improve the shot peening performance, or better clean and process the surface of the part.

Claims

1. A water drop shot peening device, characterized in that: The invention comprises a multi-degree-of-freedom robot arm (6), the end of the robot arm (6) is fixedly connected to a high-pressure nozzle (1), the outlet end of the high-pressure nozzle (1) is fixedly connected to a water droplet forming device (2), the outlet of the water droplet forming device (2) is connected to a variable-angle nozzle, and the function of the water droplet forming device (2) is to convert water from the high-pressure nozzle (1) into a string of water droplets and spray them out from the variable-angle nozzle; a high-speed camera (3) is arranged near the water droplet forming device (2) for photographing water droplets sprayed by the water droplet forming device (2); a workpiece moving platform (5) is arranged below the water droplet 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).

2. The water drop shot peening device according to claim 1, characterized in that: The water droplet forming device (2) comprises a first valve body (11) and a first valve core (12), wherein the first valve core (12) extends into a high-pressure fluid flow passage in the first valve body (11), the other end of the first valve core (12) is connected to a connecting rod (14), the other end of the connecting rod (14) is connected to an eccentric wheel (15), the eccentric wheel (15) is mounted on an output shaft of a motor (16), and the motor (16) is fixed on a motor support plate (17); the connecting rod (14), the eccentric wheel (15), the motor (16) and the motor support plate (17) are all mounted in a housing, and the housing is connected to the first valve body (11) via a first flange (13); the high-pressure nozzle (1) is connected to the first valve body (11) via a flange of the first valve body (11).

3. The water drop shot peening device according to claim 1, characterized in that: 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; 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); and the ultrasonic transducer a is connected to an ultrasonic generator a.

4. The water drop shot peening device according to claim 3, characterized in that: 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) via 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 radially fixed and axially movable.

5. The water drop shot peening device according to claim 4, characterized in that: An axial step counterbore is provided at the center of the end of the second horn (25), the large diameter end of the step counterbore 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 is less than the radius difference between the large diameter end hole and the small diameter end hole; two rectangular protrusions of the same size and corresponding position as the rectangular grooves 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 counterbore of the second horn (25), is movable in the axial direction and fixed in the radial direction, and the second valve core (23) cannot rotate in the second horn (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 counterbore of the second horn (25), and the annular baffle (210) protrudes from the step of the step counterbore, and a spring (24) is installed between the portion of the annular baffle (210) protruding from the step and the rectangular protrusion.

6. The water drop shot peening device according to claim 1, characterized in that: The water droplet forming device comprises 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 comprises a third front end cover (31) and a third rear end cover (35) connected by bolts, a third piezoelectric ceramic (34) is installed between the two, and a copper pole piece (32) is installed between every two third piezoelectric ceramics, and the third rear end cover (35) is fixedly connected to a third amplitude rod (36); the third front end cover (31) is connected to the high-pressure nozzle (1).

7. The water drop shot peening 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.

8. A water drop shot peening method, characterized in that: Using the water drop shot peening processing device as described in any one of claims 1 to 7, the method is implemented in the following steps: Step 1, fix the workpiece on the workpiece moving table (5), and adjust various parameters of the injection system 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 into the water droplet forming device (2) through the high-pressure nozzle (1) to form a stable and continuous string of water droplets; wherein the frequency range of the water droplet forming device (2) is 50 Hz-1000 Hz or 20 kHz-40 kHz; Step 3, controlling the workpiece moving table (5) to make the workpiece reach a predetermined position, and then moving the robot arm (6) along a predetermined trajectory according to the workpiece processing requirements, ensuring that the water droplet flow always acts on the workpiece surface at a set angle and distance, so as to achieve water droplet shot peening processing; 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 processing, the spray pressure, time and water drop frequency 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.

9. The water drop shot peening method according to claim 8, 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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