A device and method capable of realizing multiple laser shot peening forming under a rigid constraint layer

Abstract

The present invention provides a device and method for realizing multiple laser shot peening forming under a rigid constraint layer, including a motion system, a laser shot peening strengthening system, a laser heating and temperature rising system, a particle flow system and a working tank, wherein a workpiece to be processed is installed in the working tank, and the working tank and the particle flow system are connected to form a closed loop, and the charged black paint particles are adsorbed on the surface of the workpiece to be processed through the particle flow system; the laser heating and temperature rising system is used to make the charged black paint particles form a black paint deposition layer on the surface of the workpiece to be processed; the laser shot peening strengthening system is used to perform laser shot peening on the surface of the workpiece to be processed. The present invention utilizes the characteristic that small charged particles are easily adsorbed on the metal surface, and adopts the method of nanosecond pulse laser heating to melt and deposit tiny black paint particles at designated positions, thereby realizing timely replenishment of the absorption layer and precise control of the thickness of the absorption layer.

Description

Technical Field

[0001] The invention relates to the field of laser shock forming, and in particular to a device and method capable of realizing multiple laser shot peening forming under a rigid constraint layer. Background Art

[0002] Laser shot peening is a new method of flexible precision moldless forming. It uses a high-energy laser beam to impact the sheet material point by point. The impact of the vaporized products produced by laser ablation on the metal material causes the metal material to produce compressive plastic deformation. The plastic ductility deformation characteristics of the metal material are used to accumulate small deformations into macroscopic large deformations. It has been widely used in aerospace, space science, marine ships and other fields.

[0003] Theory and practice have proved that the confinement layer can significantly increase the pressure of the laser shock wave and prolong its duration by hindering the escape of vaporized products, thereby achieving better forming benefits.

[0004] Common constraint layers are divided into liquid constraint layers, flexible constraint layers, and rigid constraint layers. Among them, since the rigid constraint layer does not deform, the initial state of the high-pressure gas mass can be maintained for a long time, and then the vapor diffuses from the gap between the constraint layer and the workpiece.

[0005] Although the rigid constraint layer has the best constraint effect on the gasification, it is usually not used in laser shot peening at present because of the following difficulties that cannot be solved:

[0006] 1. Laser shot peening produces colored vapors that adhere to the surface of the rigid absorption layer. If they are impacted multiple times, it will prevent the laser beam from irradiating the surface of the metal workpiece and cause irreparable damage to the constraint layer.

[0007] 2. Since laser shot peening will produce pits and the center of the workpiece will be concave after forming, the gap between the rigid constraint layer and the absorption layer is too large, which is not conducive to the constraint of the vaporized products and will greatly reduce the impact force and duration.

[0008] 3. If the absorption layer is too thick, it is not conducive to the impact force being transmitted to the surface of the workpiece. If the absorption layer is too thin, the absorption layer needs to be replaced if multiple laser shot peening is performed, and the process is cumbersome. Summary of the invention

[0009] In view of the deficiencies in the prior art, the present invention provides a device and method for realizing multiple laser shot peening forming under a rigid constraint layer, utilizing the characteristic that small charged particles are easily adsorbed on the metal surface, and adopting a nanosecond pulse laser heating method to melt and deposit tiny black paint particles at specified positions, thereby realizing timely replenishment of the absorption layer and precise control of the thickness of the absorption layer, and adopting femtosecond pulse laser multiple shot peening forming with extremely high forming accuracy; the heating and temperature rising system combined with the high-speed flowing airflow can melt the black paint impurities attached to the surface of the optical glass and flexibly remove them, without damaging the optical glass and without affecting the benefit of the next laser shot peening.

[0010] The present invention achieves the above technical objectives through the following technical means.

[0011] A device capable of realizing multiple laser shot peening forming under a rigid constraint layer comprises a motion system, a laser shot peening strengthening system, a laser heating and temperature raising system, a particle flow system and a working tank.

[0012] The workpiece to be processed is installed in the working tank, and the working tank and the particle flow system are connected to form a closed loop, and the charged black paint particles are adsorbed on the surface of the workpiece to be processed through the particle flow system; the laser heating and temperature rising system is used to make the charged black paint particles form a black paint deposition layer on the surface of the workpiece to be processed; the laser shot peening strengthening system is used to perform laser shot peening on the surface of the workpiece to be processed; the motion system is used to move the laser shot peening strengthening system, the laser heating and temperature rising system and the workpiece to be processed.

[0013] Further, the particle flow system includes a housing, an electronic injector, an electronic storage chamber, a high-speed fan, a cooling rod, a particle crusher, a particle storage box, a pressure sensor probe and an air pressure pump;

[0014] A working groove is provided in the closed flow channel of the shell, and an optical glass is provided on the shell above the working groove. A particle crusher, a particle storage box, a high-speed fan, an electronic storage chamber and a workpiece to be processed are sequentially installed in the closed flow channel according to the flow direction; black paint particles are stored in the particle storage box, and the cooling rod is used to cool the recovered vaporized black paint; the particle crusher is used to crush the cooled black paint into black paint particles; an air pressure pump is provided at the outlet of the particle crusher to maintain pressure in the closed flow channel;

[0015] The upper half of the wall on one side of the particle storage box is a mesh structure, and the lower half of the wall on one side of the particle storage box is a closed boundary; the other side wall of the particle storage box is a double-layer baffle, one layer of the baffle is a mesh baffle, and the other layer is a movable closed baffle; a movable pressure plate mechanism is installed on the particle storage box, which is used to divide the particle storage box into a circulation area and a black paint particle area; the upper and lower sides of the electron storage cavity are mesh structures, and an electronic injector is installed on the electron storage cavity, which is used to generate free electrons inside the electron storage cavity.

[0016] Furthermore, the laser heating and temperature raising system includes a nanosecond laser, a second reflector and a second focusing mirror; the laser beam emitted by the nanosecond laser is reflected by the second reflector and then focused on the surface of the workpiece to be processed by the second focusing mirror, so as to make the charged black paint particles form a black paint deposition layer on the surface of the workpiece to be processed; when the height of the black paint deposition layer increases, the laser beam is focused on the black paint particle adsorption layer on the upper surface of the black paint deposition layer by changing the focal position of the second focusing mirror; the laser shot peening strengthening system includes a femtosecond laser, a first reflector and a first focusing mirror; the laser beam emitted by the femtosecond laser is reflected by the first reflector and then focused on the upper surface of the black paint deposition layer by the first focusing mirror.

[0017] Furthermore, the motion system includes a first slide rail, a first slider, a second slider, a second slide rail, a third slider and a mobile platform, the first slider and the second slider are respectively installed on the first slide rail; the first slider is connected to the first reflector, and the second slider is connected to the second reflector; the third slider is installed on the second slide rail; the third slider is connected to the second focusing mirror, and is used to change the focal position of the second focusing mirror; the workpiece to be processed is placed on the mobile platform.

[0018] Furthermore, it also includes a three-dimensional information collector, a pressure sensor and a displacement sensor. The three-dimensional information collector is aimed at the lower surface of the optical glass to capture whether there is black paint vapor attached to the lower surface of the optical glass; the displacement sensor is used to detect the thickness of the black paint deposition layer and the distance between the black paint deposition layer and the optical glass; the pressure sensor is used to detect the pressure in the closed flow channel.

[0019] A method for realizing a device for multiple laser shot peening forming under a rigid constraint layer, comprising the following steps:

[0020] The closed flow channel is filled with high-pressure gas by a pneumatic pump, and the pneumatic pump is turned off when the pressure sensor reaches a first set value;

[0021] By controlling the high-speed fan to start, the black paint particles in the particle storage box circulate in the closed flow channel; the black paint particles are charged by the electronic injector after passing through the electronic storage cavity; the charged black paint particles are adsorbed on the surface of the workpiece to be processed;

[0022] Control the movement of the second slider so that the light of the nanosecond laser is reflected by the second reflector and reaches the surface of the workpiece to be processed; focus the laser on the black paint particle layer adsorbed on the surface of the workpiece to be processed to form a black paint deposition layer; when the thickness of the black paint deposition layer reaches the designed value as determined by the displacement sensor, turn off the nanosecond laser;

[0023] Control the movement of the first slider so that the light of the femtosecond laser is reflected by the first reflector and reaches the surface of the black paint deposition layer; divide the particle storage box into a circulation area and a black paint particle area by moving the pressure plate mechanism; control the movable closed baffle to connect the circulation area with the closed flow channel; perform laser shot peening on the black paint deposition layer by the laser generated by the femtosecond laser;

[0024] A three-dimensional information collector is used to capture whether there is any black paint vapor attached to the lower surface of the optical glass. When black paint vapor exists, the laser generated by a nanosecond laser is focused on the lower surface of the optical glass for laser cleaning; the wind speed of the high-speed fan is controlled, and the airflow in the closed flow channel is used to blow away the melted or vaporized black paint attachments.

[0025] Further, the method further comprises the following steps:

[0026] During the laser shot peening process, the displacement sensor monitors the thickness of the black paint deposition layer in real time. When the thickness of the black paint deposition layer is less than a second set value, the laser shot peening process is stopped, and the movable closed baffle is controlled to connect the black paint particle area with the closed flow channel. By controlling the high-speed fan to start, the charged black paint particles are adsorbed on the surface of the black paint deposition layer to be deposited; the light of the nanosecond laser is controlled to be reflected by the second reflector to reach the surface of the black paint deposition layer; the laser focus is aimed at the black paint particle layer adsorbed on the surface of the black paint deposition layer to replenish the black paint deposition layer.

[0027] Furthermore, the focus position of the nanosecond laser is controlled according to the monitoring value of the displacement sensor, so that the thickness of the black paint deposition layer is 1 to 100 μm; by controlling the moving platform, the distance between the black paint deposition layer and the optical glass is 5 to 20 μm; the diameter of the particles in the particle storage box is within 1 μm; the black paint crusher crushes the cooled block-shaped black paint into particles with a diameter less than 1 μm.

[0028] Furthermore, the electron flow rate of the electronic injector is much greater than the instantaneous flow rate of particles in the closed flow channel passing through the high-speed fan; when the nanosecond laser heats the black paint particles to form a black paint deposition layer, the flow rate of the high-speed fan is 1 to 10 mm / s, and the movable closed baffle is controlled to move downward to increase the flow cross section;

[0029] When the femtosecond laser performs laser shot peening on the black paint deposit layer, the flow rate of the high-speed fan is 10 to 100 mm / s, and the movable closed baffle is controlled to move upward to reduce the flow cross section;

[0030] When the laser light generated by the nanosecond laser cleans the lower surface of the optical glass, the flow rate of the high-speed fan is 100-1000 mm / s, and the movable closed baffle is controlled to move upward to reduce the flow cross section.

[0031] Furthermore, the nanosecond laser uses a square spot with a side length of 0.1-1 mm, a laser energy of 0.03-5 mJ, and a laser pulse width of 5-10 ns;

[0032] The femtosecond laser uses a circular spot with a spot diameter of 3-5 mm, a laser energy of 3-15 mJ, and a laser pulse width of 300-500 fs.

[0033] The beneficial effects of the present invention are:

[0034] 1. The present invention can realize a device and method for multiple laser shot peening forming under a rigid constraint layer. A particle film can be formed on the surface of the deposition layer by the flowing fine charged black paint particles. Combined with nano-laser heating technology, the pits caused by laser shot peening and the central depression caused by workpiece deformation can be replenished in time, and precise repair can be performed to avoid the attenuation of impact benefit caused by surface morphology changes.

[0035] 2. The present invention can realize a device and method for multiple laser shot peening forming under a rigid constraint layer. The infrared rangefinder can detect the thickness of the black paint deposition layer and the distance between the black paint deposition layer and the rigid constraint layer in real time, effectively ensuring the constraint effect of the constraint layer on the gasification and reducing the attenuation of the impact force along the deposition layer.

[0036] 3. The present invention can realize a device and method for multiple laser shot peening forming under a rigid constraint layer. The three-dimensional information collector can detect the adhesion of vaporized substances on the surface of the rigid constraint layer in real time, and the control system can clean and remove them in time, thereby avoiding the absorption of laser energy by stains, improving the utilization rate of laser energy and reducing the damage to the rigid constraint layer, and ensuring that the effect of laser shot peening remains basically unchanged each time.

[0037] 4. The present invention can realize a device and method for multiple laser shot peening forming under a rigid constraint layer. The black paint particles are vaporized and condensed in a closed space for circulation. The particle crusher can crush the condensed block black paint into particles that meet the requirements for repeated use.

[0038] 5. The present invention can realize a device and method for multiple laser shot peening under a rigid constraint layer. During laser shot peening, the airflow flowing in the pores of the absorption layer and the constraint layer can carry away the black paint vapor, avoiding solidification on the surface of the optical glass and affecting the shot peening effect.

[0039] 6. The present invention can realize an apparatus and method for multiple laser shot peening under a rigid constraint layer. During the laser pulse process, the temperature and pressure of the target surface accumulate to form an unbalanced Knudsen layer. The pressure of the Knudsen layer is rapidly released, resulting in an exponential decay of the overpressure during the evolution of the shock wave. The decay of the overpressure is because the air density is relatively low and the compressibility is relatively high. The laser ablation products continuously compress the air to work, resulting in irreversible energy loss. The air pressure pump ensures that the initial environment of the laser shot peening area is in a high-pressure state, the density increases, and the compressibility decreases. The peak value of the Knudsen layer before the pressure is released can be increased, and the speed at which the vaporized product squeezes the air can be slowed down, thereby reducing the decay rate of the overpressure. This increases the peak value and duration of the impact force, which is beneficial to laser shot peening. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, it is obvious that other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 This is an assembly diagram of the device for realizing multiple laser shot peening forming under a rigid constraint layer according to the present invention.

[0042] Figure 2 This is a process flow chart of the processing method for realizing multiple laser shot peening forming under a rigid constraint layer as described in the present invention.

[0043] In the figure:

[0044] 1-first slide rail; 2-first slider; 3-second slider; 4-femtosecond laser; 5-first reflector; 6-second reflector; 7-nanosecond laser; 8-computer; 9-three-dimensional information collector; 10-first focusing mirror; 11-second focusing mirror; 12-second slide rail; 13-third slider; 14-optical glass; 15-displacement sensor; 16-housing; 17-black paint particles; 18-motion controller; 19-black paint deposition layer; 20-workpiece to be processed; 21-moving platform; 22-electronic injector; 23-electronic storage chamber; 24-free electrons; 25-high-speed fan; 26-refrigeration rod; 27-particle crusher; 28-particle storage box; 29-wind speed controller; 30-movable pressure plate mechanism; 31-pressure sensor; 32-baffle controller; 33-air pressure pump. DETAILED DESCRIPTION

[0045] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0046] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0048] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] like Figure 1As shown, the device for realizing multiple laser shot peening forming under a rigid constraint layer described in the present invention comprises a motion system, a laser shot peening strengthening system, a laser heating and temperature rising system, a particle flow system and a working groove, in which a workpiece 20 to be processed is installed, and the working groove and the particle flow system are connected to form a closed loop, and the charged black paint particles 17 are adsorbed on the surface of the workpiece 20 to be processed through the particle flow system; the laser shot peening strengthening system and the laser heating and temperature rising system are respectively located above the workpiece 20 to be processed, and the laser heating and temperature rising system is used to make the charged black paint particles 17 form a black paint deposition layer 19 on the surface of the workpiece 20 to be processed; the laser shot peening strengthening system is used to perform laser shot peening on the surface of the workpiece 20 to be processed; and the motion system is used to move the laser shot peening strengthening system, the laser heating and temperature rising system and the workpiece 20 to be processed. The present invention utilizes the characteristic that small charged particles are easily adsorbed on the metal surface, and adopts the method of nanosecond pulse laser heating to melt and deposit tiny black paint particles at designated positions, thereby realizing timely replenishment of the absorption layer and precise control of the thickness of the absorption layer. It adopts femtosecond pulse laser for multiple shot peening and has extremely high forming accuracy. The heating and temperature rising system combined with high-speed airflow can melt the black paint impurities attached to the surface of the optical glass and flexibly remove them without damaging the optical glass and affecting the benefits of the next laser shot peening.

[0050] The particle flow system includes a shell 16, an electronic injector 22, an electronic storage chamber 23, a high-speed fan 25, a cooling rod 26, a particle crusher 27, a particle storage box 28, a pressure sensor probe 31 and an air pressure pump 33; a working groove is provided in the closed flow channel of the shell 16, an optical glass 14 is provided on the shell above the working groove, and a particle crusher 27, a particle storage box 28, a high-speed fan 25, an electronic storage chamber 23 and a workpiece to be processed 20 are installed in the closed flow channel in sequence according to the flow direction; black paint particles are stored in the particle storage box 28, and the cooling rod 26 is used to cool the recovered vaporized black paint; the particle crusher 27 is used to break the cooled black paint into black paint particles particles; an air pressure pump 33 is provided at the outlet of the particle crusher 27 for maintaining pressure in the closed flow channel; the upper half of the wall on one side of the particle storage box 28 is a mesh structure, and the lower half of the wall on one side of the particle storage box 28 is a closed boundary; the other side wall of the particle storage box 28 is a double-layer baffle, one layer of the baffle is a mesh baffle, and the other layer is a movable closed baffle; a movable movable pressure plate mechanism 30 is installed on the particle storage box 28, for dividing the particle storage box 28 into a circulation area and a black paint particle area; the upper and lower sides of the electron storage cavity 23 are mesh structures, and an electron injector 22 is installed on the electron storage cavity 23, for generating free electrons 24 inside the electron storage cavity 23.

[0051] The laser heating and temperature raising system comprises a nanosecond laser 7, a second reflecting mirror 6 and a second focusing mirror 11; the laser beam emitted by the nanosecond laser 7 is reflected by the second reflecting mirror 6 and then focused on the surface of the workpiece 20 to be processed by the second focusing mirror 11, so as to make the charged black paint particles 17 form a black paint deposition layer 19 on the surface of the workpiece 20 to be processed; when the height of the black paint deposition layer 19 increases, the focal position of the second focusing mirror 11 is changed so that the laser beam is always focused on the adsorption layer of the black paint particles 17 on the upper surface of the black paint deposition layer 19; the laser shot peening strengthening system comprises a femtosecond laser 4, a first reflecting mirror 5 and a first focusing mirror 10; the laser beam emitted by the femtosecond laser 4 is reflected by the first reflecting mirror 5 and then focused on the upper surface of the black paint deposition layer 19 by the first focusing mirror 10.

[0052] The motion system includes a first slide rail 1, a first slider 2, a second slider 3, a second slide rail 12, a third slider 13 and a mobile platform 21, wherein the first slider 2 and the second slider 3 are respectively mounted on the first slide rail 1; the first slider 2 is connected to the first reflector 5, and the second slider 3 is connected to the second reflector 6; the third slider 13 is mounted on the second slide rail 12; the third slider 13 is connected to the second focusing mirror 11, and drives the second focusing mirror 11 to move up and down so as to change the position of the focus relative to the black paint deposition layer 19 and the optical glass 14 in real time, so as to change the focus position of the second focusing mirror 11; a workpiece 20 to be processed is placed on the mobile platform 21, and the mobile platform 21 is connected to the motion controller 18, and the maximum distance between the optical glass 14 and the mobile platform 21 can reach 10 mm.

[0053] The device for realizing multiple laser shot peening under a rigid constraint layer described in the present invention also includes a three-dimensional information collector 9, a pressure sensor 31 and a displacement sensor 15. The three-dimensional information collector 9 is aimed at the lower surface of the optical glass to capture whether there is black paint vapor attached to the lower surface of the optical glass 14; the displacement sensor 15 is used to detect the thickness of the black paint deposition layer 19 and the distance between the black paint deposition layer 19 and the optical glass 14; the pressure sensor 31 is used to detect the pressure in the closed flow channel.

[0054] The computer 8 controls the first slider 2, the second slider 3, the femtosecond laser 4, the nanosecond laser 7, the three-dimensional information collector 9, the third slider 13, the displacement sensor 15, the motion controller 18, the electronic injector 22, the wind speed controller 29, the pressure sensor 30, the baffle controller 32, and the air pressure pump 33. The wind speed controller 29 is used to control the wind speed of the high-speed fan 25. The baffle controller 32 is used to control the movable closed baffle on the particle storage box 28. The motion controller 18 is used to control the movement of the mobile platform 21.

[0055] like Figure 2As shown, the processing method of the device capable of realizing multiple laser shot peening forming under the rigid constraint layer according to the present invention comprises the following steps:

[0056] The closed flow channel is filled with high-pressure gas through the air pressure pump 33, and the air pressure pump 33 is turned off when the pressure sensor 31 reaches a first set value;

[0057] By controlling the high-speed fan 25 to start, the black paint particles 17 in the particle storage box 28 circulate in the closed flow channel; the black paint particles 17 are charged by the electronic injector 22 after passing through the electronic storage chamber 23; the charged black paint particles 17 are adsorbed on the surface of the workpiece 20 to be processed;

[0058] The second slider 3 is controlled to move so that the light of the nanosecond laser 7 is reflected by the second reflector 6 to reach the surface of the workpiece 20 to be processed; the laser focus is aligned with the black paint particle layer adsorbed on the surface of the workpiece 20 to be processed to form a black paint deposition layer 19; when the thickness of the black paint deposition layer 19 reaches the designed value as determined by the displacement sensor 15, the nanosecond laser 7 is turned off;

[0059] The first slider 2 is controlled to move so that the light of the femtosecond laser 4 is reflected by the first reflector 5 to reach the surface of the black paint deposition layer 19; the particle storage box 28 is divided into a circulation area and a black paint particle area by moving the pressure plate mechanism 30; the movable closed baffle is controlled to connect the circulation area with the closed flow channel; the black paint deposition layer 19 is laser peened by the laser generated by the femtosecond laser 4;

[0060] The three-dimensional information collector 9 is used to capture whether there is any black paint vapor attached to the lower surface of the optical glass 14. When black paint vapor exists, the laser generated by the nanosecond laser 7 is focused on the lower surface of the optical glass 14 for laser cleaning; the wind speed of the high-speed fan 25 is controlled, and the airflow in the closed flow channel is used to blow away the melted or vaporized black paint attachments.

[0061] During the laser shot peening process, the displacement sensor 15 monitors the thickness of the black paint deposition layer 19 in real time. When the thickness of the black paint deposition layer 19 is less than the second set value, the laser shot peening process is stopped, and the movable closed baffle is controlled to connect the black paint particle area with the closed flow channel. By controlling the high-speed fan 25 to start, the charged black paint particles 17 are adsorbed on the surface of the black paint deposition layer 19 to be deposited; the light of the nanosecond laser 7 is controlled to be reflected by the second reflector 6 to reach the surface of the black paint deposition layer 19; the laser focus is aligned with the black paint particle layer adsorbed on the surface of the black paint deposition layer 19 to replenish the black paint deposition layer 19.

[0062] The focus position of the nanosecond laser 7 is controlled according to the monitoring value of the displacement sensor 15, so that the thickness of the black paint deposition layer 19 is 1-100 μm; by controlling the mobile platform 21, the distance between the black paint deposition layer 19 and the optical glass 14 is 5-20 μm, which ensures that the optical glass 14 has a restraining effect on the laser shot peening and is not easy to break the optical glass; the maximum distance between the mobile platform 21 and the optical glass 14 is 10 mm, which is convenient for the flow of black paint particles 17 and the deposition of the black paint deposition layer 19. The particle diameter in the particle storage box 28 is within 1 μm; the black paint crusher 27 crushes the blocky black paint after cooling into particles with a diameter of less than 1 μm.

[0063] When the nanosecond laser 7 heats the black paint particles 17 to form a black paint deposition layer 19, the flow rate of the high-speed fan 25 is 1 to 10 mm / s, and the movable closed baffle is controlled to move downward to increase the flow cross-section; when the femtosecond laser 4 performs laser shot peening on the black paint deposition layer 19, the flow rate of the high-speed fan 25 is 10 to 100 mm / s, and the movable closed baffle is controlled to move upward to reduce the flow cross-section; when the laser generated by the nanosecond laser 7 cleans the lower surface of the optical glass 14, the flow rate of the high-speed fan 25 is 100 to 1000 mm / s, and the movable closed baffle is controlled to move upward to reduce the flow cross-section.

[0064] The nanosecond laser 7 uses a square spot with a side length of 0.1-1 mm, a laser energy of 0.03-5 mJ, and a laser pulse width of 5-10 ns; the femtosecond laser 4 uses a circular spot with a spot diameter of 3-5 mm, a laser energy of 3-15 mJ, and a laser pulse width of 300-500 fs.

[0065] The electron flow rate of the electronic injector 22 is much greater than the instantaneous flow rate of the particles in the closed flow channel passing through the high-speed fan 25, ensuring that more than 95% of the attached electrons of the black paint particles 17 are negatively charged and can be adsorbed on the surface of the metal workpiece to form a thin layer of black paint particles for a short time of 1 to 3 seconds. This is because when the particles are charged, like charges repel each other; when the particle electrons are plundered by the metal workpiece and become uncharged, the black paint particles 17 will be blown away by the high-speed high-pressure fluid due to the lack of adsorption force, which not only prevents the black paint particles 17 from sticking to each other, but also facilitates the high-precision point-by-point and surface-by-surface repair and layer-by-layer rapid deposition of the black paint deposition layer 19. When the black paint particles 17 are heated and melted to become the black paint deposition layer 19, the contact between the black paint deposition layer 19 and the metal workpiece for more than 3 seconds will become electrically neutral, and the black paint deposition layer 19 can briefly adsorb the black paint particles 17 for 1 to 3 seconds.

[0066] The method for realizing multiple laser shot peening forming under a rigid constraint layer in Example 1 comprises the following steps:

[0067] S1: The workpiece 20 to be processed is installed in the working tank. The workpiece 20 to be processed is a metal workpiece. Generally, it is a micron / nano-level mechanical electronic and MEMS product. The air pressure pump 33 is turned on to fill the closed flow channel with high-pressure gas. When the pressure sensor 30 reaches 2-5atm, the air pressure pump 33 is turned off;

[0068] S2: The computer 8 controls the electronic injector 22, the wind speed controller 29, the cooling rod 26, and the particle crusher 27 to start, so that the black paint particles 17 in the particle storage box 28 circulate in the closed flow channel. The black paint particles 17 are negatively charged after passing through the electronic storage chamber 23, and the charged black paint particles 17 have a short adsorption effect when passing through the surface of the metal workpiece;

[0069] S3: The computer 8 controls the movement of the second slider 3 so that the light of the nanosecond laser 7 is reflected by the second reflector 6 to reach the coordinate origin of the processing area. At this time, the nanosecond laser 7, the motion controller 18, the third slider 13 and the non-contact infrared rangefinder are started. The motion controller 18 controls the three-dimensional movement of the mobile platform 21. The laser focus is aimed at the black paint particle layer temporarily adsorbed on the surface of the metal workpiece 20, so that it melts and gradually accumulates to form a black paint deposition layer 19. The thickness of the black paint deposition layer 19 is observed by the non-contact infrared rangefinder. After reaching a suitable thickness, the nanosecond laser 7, the third slider 13 and the wind speed controller 29 are turned off, and the second slider 3 is started to control the second reflector 6 to move away from the top of the workbench. The motion controller 18 controls the mobile platform 21 to return to its original position and rise a certain distance so that the distance between the black paint deposition layer and the optical glass 14 is appropriate.

[0070] S4: The computer 8 controls the movement of the first slider 2 so that the light of the femtosecond laser 4 is reflected by the first reflector 5 to reach the coordinate origin of the processing area, and the movable pressure plate mechanism 30 is started to divide the particle storage box 28 into a circulation area and a black paint particle area, and the movable closed baffle is controlled to connect the circulation area with the closed flow channel; and the wind speed controller 29 is controlled to make the gas reach a suitable flow rate. At this time, the femtosecond laser 4, the motion controller 18, and the three-dimensional information collector 9 are started to realize multiple laser shot peening of the black paint deposition layer 19;

[0071] S5: The non-contact infrared rangefinder monitors the thickness of different sections of the entire plane of the black paint deposition layer 19 at any time. When the thickness of a certain section is lower than a certain range, the S3 operation is repeated to replenish the black paint deposition layer 19 in a directional manner;

[0072] S6: The three-dimensional information collector 9 captures at any time whether there is black paint vapor attached to the lower surface of the optical glass 14. If there is, the second slider 3, the nanosecond laser 7, the motion controller 18, the third slider 13, the wind speed controller 29, and the baffle controller 32 are started, and appropriate laser parameters are selected to focus the laser on the black area to melt or vaporize the black paint attachment. The baffle controller 32 controls the baffle to be higher than the particle storage height in the particle storage box 28, and the wind speed controller 29 controls the wind speed of the high-speed fan 25, so that the pure high-pressure airflow in the pipeline flows at a high speed to blow away the melted or vaporized black paint attachment;

[0073] S7: Cycle S4-S6, complete the laser shot peening of the workpiece, and turn off all equipment.

[0074] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0075] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device capable of realizing multiple laser shot peening forming under a rigid constraint layer, characterized in that: It includes motion system, laser shot peening system, laser heating system, particle flow system and working tank. The workpiece to be processed (20) is installed in the working tank, and the working tank and the particle flow system are connected to form a closed loop, and the charged black paint particles (17) are adsorbed on the surface of the workpiece to be processed (20) through the particle flow system; the laser heating and temperature rising system is used to make the charged black paint particles (17) form a black paint deposition layer (19) on the surface of the workpiece to be processed (20); the laser shot peening system is used to perform laser shot peening on the surface of the workpiece to be processed (20); and the motion system is used to move the laser shot peening system, the laser heating and temperature rising system, and the workpiece to be processed (20); The particle flow system comprises a housing (16), an electronic injector (22), an electronic storage chamber (23), a high-speed fan (25), a cooling rod (26), a particle crusher (27), a particle storage box (28), a pressure sensor (31) and an air pressure pump (33); A working groove is provided in the closed flow channel of the shell (16); an optical glass (14) is provided on the shell above the working groove; a particle crusher (27), a particle storage box (28), a high-speed fan (25), an electronic storage chamber (23) and a workpiece to be processed (20) are installed in sequence in the closed flow channel according to the flow direction; black paint particles are stored in the particle storage box (28); the cooling rod (26) is used to cool the recovered vaporized black paint; the particle crusher (27) is used to crush the cooled black paint into black paint particles; an air pressure pump (33) is provided at the outlet of the particle crusher (27) to maintain pressure in the closed flow channel; The upper half of one side wall of the particle storage box (28) is a mesh structure, and the lower half of one side wall of the particle storage box (28) is a closed boundary; the other side wall of the particle storage box (28) is a double-layer baffle, one layer of the baffle is a mesh baffle, and the other layer is a movable closed baffle; a movable movable plate mechanism (30) is installed on the particle storage box (28) for dividing the particle storage box (28) into a circulation area and a black paint particle area; the upper and lower sides of the electron storage cavity (23) are mesh structures, and an electron injector (22) is installed on the electron storage cavity (23) for generating free electrons (24) inside the electron storage cavity (23); The laser heating and temperature raising system comprises a nanosecond laser (7), a second reflecting mirror (6) and a second focusing mirror (11); the laser beam emitted by the nanosecond laser (7) is reflected by the second reflecting mirror (6) and then focused on the surface of the workpiece (20) to be processed by the second focusing mirror (11), so as to form a black paint deposition layer (19) on the surface of the workpiece (20) to be processed by the charged black paint particles (17); when the height of the black paint deposition layer (19) increases, the laser beam is focused on the adsorption layer of the black paint particles (17) on the upper surface of the black paint deposition layer (19) by changing the focal position of the second focusing mirror (11); the laser shot peening strengthening system comprises a femtosecond laser (4), a first reflecting mirror (5) and a first focusing mirror (10); the laser beam emitted by the femtosecond laser (4) is reflected by the first reflecting mirror (5) and then focused on the upper surface of the black paint deposition layer (19) by the first focusing mirror (10).

2. The device for realizing multiple laser shot peening under a rigid constraint layer according to claim 1, characterized in that: The motion system comprises a first slide rail (1), a first slider (2), a second slider (3), a second slide rail (12), a third slider (13) and a moving platform (21); the first slider (2) and the second slider (3) are respectively mounted on the first slide rail (1); the first slider (2) is connected to a first reflector (5), and the second slider (3) is connected to a second reflector (6); the third slider (13) is mounted on the second slide rail (12); the third slider (13) is connected to a second focusing mirror (11) and is used to change the focal position of the second focusing mirror (11); and a workpiece (20) to be processed is placed on the moving platform (21).

3. The device for realizing multiple laser shot peening under a rigid constraint layer according to claim 1, characterized in that: It also includes a three-dimensional information collector (9), a pressure sensor (31) and a displacement sensor (15); the three-dimensional information collector (9) is aimed at the lower surface of the optical glass to capture whether black paint vapor is attached to the lower surface of the optical glass (14); the displacement sensor (15) is used to detect the thickness of the black paint deposition layer (19) and the distance between the black paint deposition layer (19) and the optical glass (14); and the pressure sensor (31) is used to detect the pressure in the closed flow channel.

4. A processing method for the device capable of realizing multiple laser shot peening forming under a rigid constraint layer according to claim 1, characterized in that: The following steps are involved: The closed flow channel is filled with high-pressure gas by means of an air pressure pump (33), and the air pressure pump (33) is turned off when the pressure sensor (31) reaches a first set value; By controlling the high-speed fan (25) to start, the black paint particles (17) in the particle storage box (28) circulate in the closed flow channel; the black paint particles (17) are charged by the electronic injector (22) after passing through the electronic storage chamber (23); the charged black paint particles (17) are adsorbed on the surface of the workpiece (20) to be processed; Controlling the movement of the second slider (3) so that the light of the nanosecond laser (7) is reflected by the second reflector (6) and reaches the surface of the workpiece (20) to be processed; aligning the laser focus with the black paint particle layer adsorbed on the surface of the workpiece (20) to form a black paint deposition layer (19); when the displacement sensor (15) determines that the thickness of the black paint deposition layer (19) reaches the designed value, turning off the nanosecond laser (7); Controlling the movement of the first slider (2) so that the light of the femtosecond laser (4) is reflected by the first reflector (5) and reaches the surface of the black paint deposition layer (19); dividing the particle storage box (28) into a circulation area and a black paint particle area by moving the pressure plate mechanism (30); controlling the movable closed baffle to connect the circulation area with the closed flow channel; and performing laser shot peening on the black paint deposition layer (19) by using the laser light generated by the femtosecond laser (4); A three-dimensional information collector (9) is used to detect whether there is any black paint vapor attached to the lower surface of the optical glass (14). When there is any black paint vapor, laser light generated by a nanosecond laser (7) is focused onto the lower surface of the optical glass (14) for laser cleaning. The wind speed of the high-speed fan (25) is controlled to use the airflow in the closed flow channel to blow away the melted or vaporized black paint attachments.

5. The processing method of the device capable of realizing multiple laser shot peening forming under a rigid constraint layer according to claim 4, characterized in that: The following steps are also included: During the laser shot peening process, the displacement sensor (15) monitors the thickness of the black paint deposition layer (19) in real time. When the thickness of the black paint deposition layer (19) is less than a second set value, the laser shot peening process is stopped, the movable closed baffle is controlled to connect the black paint particle area with the closed flow channel, and the high-speed fan (25) is controlled to start so that the charged black paint particles (17) are adsorbed on the surface of the black paint deposition layer (19) to be deposited; the light of the nanosecond laser (7) is controlled to be reflected by the second reflector (6) to reach the surface of the black paint deposition layer (19); and the laser focus is aligned with the black paint particle layer adsorbed on the surface of the black paint deposition layer (19) to replenish the black paint deposition layer (19).

6. The processing method of the device capable of realizing multiple laser shot peening forming under a rigid constraint layer according to claim 4, characterized in that: The focus point position of the nanosecond laser (7) is controlled according to the monitoring value of the displacement sensor (15), so that the thickness of the black paint deposition layer (19) is 1 to 100 μm; the distance between the black paint deposition layer (19) and the optical glass (14) is 5 to 20 μm by controlling the moving platform (21); the diameter of the particles in the particle storage box (28) is within 1 μm; and the particle crusher (27) crushes the cooled block-shaped black paint into particles with a diameter less than 1 μm.

7. The processing method of the device capable of realizing multiple laser shot peening forming under a rigid constraint layer according to claim 4, characterized in that: The electron flow rate of the electronic injector (22) is much greater than the instantaneous flow rate of particles in the closed flow channel passing through the high-speed fan (25); when the nanosecond laser (7) heats the black paint particles (17) to form a black paint deposition layer (19), the flow rate of the high-speed fan (25) is 1-10 mm / s, and the movable closed baffle is controlled to move downward to increase the flow cross section; when the femtosecond laser (4) performs laser shot peening on the black paint deposition layer (19), the flow rate of the high-speed fan (25) is 10-100 mm / s, and the movable closed baffle is controlled to move upward to reduce the flow cross section; when the laser light generated by the nanosecond laser (7) cleans the lower surface of the optical glass (14), the flow rate of the high-speed fan (25) is 100-1000 mm / s, and the movable closed baffle is controlled to move upward to reduce the flow cross section.

8. The processing method of the device capable of realizing multiple laser shot peening forming under a rigid constraint layer according to claim 4, characterized in that: The nanosecond laser (7) uses a square spot with a spot side length of 0.1-1 mm, a laser energy of 0.03-5 mJ, and a laser pulse width of 5-10 ns; the femtosecond laser (4) uses a circular spot with a spot diameter of 3-5 mm, a laser energy of 3-15 mJ, and a laser pulse width of 300-500 fs.

Images