One-way multi-stage air curtain purification protection device for laser shock peening

Abstract

A one-way multi-stage air curtain purification protection device for laser shock peening is characterized in that a first-stage high-pressure and high-speed air curtain and a second-stage high-pressure and high-speed air curtain are respectively generated through a semi-open O-shaped protection device and a plurality of three-way air curtain generators which are connected in series, and multi-stage one-way airflow from top to bottom is formed between a lens and an impact target surface; and the water drops and particle dust are prevented from adhering to the surface of the lens. High-pressure airflow of the semi-open O-shaped protection device and the three-way air curtain generator is sucked into the air purification device through the exhaust pipe to be filtered, and the high-pressure airflow is exhausted into air after water drops and particle dust are removed. Meanwhile, adsorption layer particle dust in the air is adsorbed by a one-way adsorption filter screen on the periphery of the main exhaust pipe, enters the air purification device, and is discharged into the air after being filtered. According to the invention, the stability and consistency of laser shock peening are effectively ensured; the convex lens is protected from being polluted by backwash water drops and adsorption layer particle dust, and meanwhile the adsorption layer particle dust generated in the laser shock peening process is purified and treated.

Description

Technical Field

[0001] The invention relates to laser processing, and in particular to a unidirectional multi-stage air curtain purification protection device for laser shock strengthening. Background Art

[0002] Laser shock peening is a surface strengthening method that can improve the mechanical properties of materials by using the shock effect of laser-induced high-power density stress waves to cause plastic deformation and grain refinement on the surface of metal and alloy materials, increase the surface dislocation density, and thus produce residual compressive stress and a hardened layer. When implementing laser shock peening, traditional methods usually require the pre-setting of an absorption protection layer on the surface of the workpiece and covering it with a constraint layer. Among them, the laminar water layer is often used as a constraint layer due to its characteristics.

[0003] When a high-intensity laser beam acts on the absorption layer, the absorption layer vaporizes and ionizes in a very short time to form a large amount of high-temperature (>10 7 K), high-pressure (>1GPa) plasma, which is constrained by the water layer and instantly converted into a high-pressure shock wave (GPa level). During this process, water droplets and dust are often sputtered by the shock wave and propagate rapidly in the opposite direction of the laser transmission direction. The reflective lens or focusing lens closest to the workpiece will be adhered to by water droplets and dust first. Under strong laser irradiation, these optical components are easily damaged, which shortens the life of the focusing lens or reflector, and reduces the laser energy projected to the target surface, which has an adverse effect on the overall quality and effect of laser shock strengthening.

[0004] Patent document CN110275267B adds a compressed gas protection tube under the focusing lens to protect the focusing lens and prevent splashing water droplets and coating vaporized products from adhering and contaminating. However, this method has defects: the air pressure of 1.5 to 2 times the atmospheric pressure in the protection tube will form an airflow blowing toward the water layer on the target surface, which may destroy the thickness and stability of the water flow layer serving as the impact target surface inhibition layer. At the same time, it also fails to promptly remove the coating vaporized products and dust pollution generated during impact strengthening. Summary of the invention

[0005] In view of the above problems, the present invention proposes a unidirectional multi-stage air curtain purification protection device for laser shock peening, which can effectively ensure the stability and consistency of laser shock peening on the one hand; while protecting the convex lens sheet / reflective lens sheet from contamination by back-splash water droplets and adsorption layer particle dust, it purifies the adsorption layer particle dust generated during the laser shock peening process.

[0006] The technical solution of the present invention is as follows:

[0007] A unidirectional multi-stage air curtain purification protection device for laser shock peening, comprising an air purification device, a soundproof cover, and a front variable iris, a rear variable iris, a workpiece and a six-axis robot arm for controlling the movement of the workpiece arranged in sequence along the laser transmission direction in the soundproof cover, characterized in that it also comprises at least two three-way unidirectional air curtain generators and a semi-open O-shaped protection device distributed along the laser transmission direction;

[0008] The three-way one-way air curtain generator generates a high-pressure and high-speed air curtain to block water droplets and particle dust splashed back in the opposite direction of the light beam, including:

[0009] The main body has an optical axis cavity provided inside for light beam transmission;

[0010] A gas splitter, arranged on the main body, for dividing the airflow input from the air inlet pipe into three paths: a first high-pressure airflow, a low-pressure airflow, and a second high-pressure airflow;

[0011] An air inlet pipe, connected to the gas splitter, for inputting purified compressed air;

[0012] Two inclined inlets, a first inlet and a second inlet, are respectively provided on the main body along the upper and lower axes, and two inclined inlets, a third inlet and a fourth inlet, are respectively provided along the left and right axes; the first high-pressure gas flow is divided into two paths through the first high-pressure branch pipe and the one-to-two gas pipe, and enters the optical axis cavity through the first inlet and the second inlet respectively, and the second high-pressure gas flow is divided into two paths through the second high-pressure branch pipe and the one-to-two gas pipe, and enters the optical axis cavity through the third inlet and the fourth inlet respectively, and the two high-pressure gas flows are respectively transmitted in the optical axis cavity in the same direction and in the opposite direction along the laser transmission direction;

[0013] The narrow slit rectangular airway is connected to the bottom of the low-pressure airflow and is formed by alternating rectangular grooves and groove walls uniformly distributed along the two long side walls, and the rectangular grooves and groove walls are symmetrical along the center line of the narrow slit rectangular airway, so that one low-pressure airflow forms turbulence through the narrow slit rectangular airway and converges with the two high-pressure airflows to form a high-pressure and high-speed air curtain, which penetrates the optical axis cavity, thereby blocking water droplets and particulate dust splashed back in the opposite direction of the light beam, and enters the air purification device along the bottom of the narrow slit rectangular airway through the collection port and the exhaust pipe;

[0014] The semi-open O-shaped protective device includes a first hemispherical isolation cover and a second hemispherical isolation cover respectively located on and below the optical path, and a semi-cylindrical transparent enclosure connecting the first hemispherical isolation cover and the second hemispherical isolation cover. At least two parallel air knives are arranged in the first hemispherical isolation cover. The air knives are connected to the purified compressed air supply device through a compressed air inlet pipe and a pressure valve to form a first-stage high-pressure air curtain, which blocks most of the sputtered water droplets and particulate dust generated during laser shock strengthening in the second hemispherical isolation cover in the semi-open O-shaped protective device, and enters the purification device through the exhaust pipe to protect the cleanliness and stability of the optical path.

[0015] Furthermore, the first-stage high-pressure and high-speed air curtain formed by the purified compressed air sprayed by the air knife works together with the high-pressure and high-speed air curtain generated by the three-way one-way air curtain generator to form a multi-stage air curtain protection, which completely blocks the water droplets and particulate dust splashed back in the opposite direction of the light beam, and protects the convex lens / reflective lens in the optical path from being contaminated by the back-splashed water droplets and the adsorption layer particulate dust.

[0016] Preferably, the ratio of the height of the groove wall to the length of the rectangular groove is 1:2 to 1:4, forming a microstructure that runs through the inlet to the outlet of the narrow slit rectangular airway, making the airflow speed along the narrow slit rectangular airway faster.

[0017] Preferably, the distance between the air outlet of the air knife and the laser beam is adjustable in the range of 5 mm to 50 mm, and the orientation of the air knife and the semi-cylindrical transparent enclosure is adjustable to ensure that the maximum plane of the air knife and the two vertical side planes of the semi-cylindrical transparent enclosure are parallel to the workpiece surface.

[0018] Preferably, the distance between the air outlet of the air knife and the laser beam is 10 mm.

[0019] Preferably, the air intake pipe is externally connected to a purified compressed air supply device, and the air pressure is adjusted by an air pressure valve so that the air pressure in the compressed air intake pipe is maintained between 0.4 MPa and 1.4 MPa.

[0020] Preferably, threaded holes are provided on the outer wall of the body, which are connected in pairs by connecting rods to form a second-stage high-pressure and high-speed air curtain in series.

[0021] Preferably, the air purification device includes a main exhaust duct, an exhaust fan, a multi-layer filter element and an exhaust port. The gas inside the soundproof cover is sucked into the main exhaust duct through a one-way adsorption filter, and is discharged from the exhaust port after being filtered through the multi-layer filter element, so as to suck and purify water droplets and particulate dust in the working space.

[0022] Preferably, in the semi-open O-shaped protective device, purified compressed air enters the compressed air inlet pipe from the purified compressed air supply device, and enters the air knife through the inlet pipe air pressure valve and the air distribution pipe. The high-pressure airflow forms a first-stage high-pressure and high-speed air curtain through the air knife to blow most of the water droplets and particulate dust splashed back during laser impact strengthening toward the second hemispherical isolation cover. Under the combined action of the high-speed and high-pressure airflow and the suction from the exhaust pipe, the water droplets and particulate dust in the second hemispherical isolation cover are brought to the main exhaust pipe, pass through the one-way adsorption filter, and then enter the air purification device for purification.

[0023] Preferably, the air pressures of the two high-pressure airflows are the same, and the air pressure ratio of the two high-pressure airflows to the remaining low-pressure airflow is 1.5:1 to 6:1.

[0024] Preferably, the motion trajectory and control program of the six-axis robot are edited and set according to the position of the workpiece, the position of the water tank, the position of the laminar suppression layer and the position of the laser beam to ensure that the motion frequency of the six-axis robot is synchronized with the repetition rate of the laser beam to achieve precise impact strengthening of the workpiece surface.

[0025] Preferably, a guide plate for regulating air flow is also provided inside the soundproof cover to optimize the air flow path and improve air purification efficiency.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) A double air knife is used to generate a high-pressure and high-speed air curtain in the hemispherical isolation cover, which splashes most of the water droplets and particulate dust in the light path back from the workpiece surface and brings them into the exhaust pipe. As the first-level high-pressure and high-speed air curtain in the light path, it can significantly reduce the water droplets and particulate dust passing through the hemispherical isolation cover, and achieve the technical effect of protecting the light path lenses.

[0028] (2) A three-way one-way air curtain generator is used to divide the purified compressed air into high-pressure and low-pressure airflows. The high-pressure airflows converge toward the center of the optical axis cavity along the horizontal direction, and the low-pressure airflows converge toward the center of the optical axis cavity from top to bottom through the rectangular narrow slit airway along the vertical direction. The three airflows interact with each other at the center of the optical axis cavity to form turbulence, so that the pressure and speed of the air curtain reach the maximum value.

[0029] (3) A method of combining a semi-open O-shaped protection device with a series of multi-stage three-way one-way air curtain generators is used to form multiple high-pressure and high-speed air curtains, which completely absorb the water droplets and particulate dust generated during laser shock intensive processing into the purification protection device, thereby achieving the technical effect of protecting the laser lens without component loss and laser energy loss.

[0030] (4) It has a wide range of applications and can be applied to laser shock strengthening of metal materials with concave and convex surfaces, thickening, corners, special shapes, and large sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of an embodiment of a unidirectional multi-stage air curtain purification and protection device for impact strengthening of the present invention;

[0032] Figure 2 It is a structural schematic diagram of a three-way one-way air curtain generator in the present invention;

[0033] Figure 3 It is a schematic diagram of the structure of the narrow slit rectangular airway in the present invention;

[0034] Figure 4 It is a structural schematic diagram of a semi-open O-shaped protection device in the present invention;

[0035] In the figure:

[0036] 01-Soundproof cover

[0037] 02-Front variable aperture

[0038] 03-Three-way one-way air curtain generator; 30, body; 31, optical axis cavity; 32, air inlet pipe; 33, gas diverter; 34, first high-pressure airflow; 35, low-pressure airflow; 36, second high-pressure airflow; 37, first high-pressure branch pipe; 38, one-to-two air pipes; 39, first inlet; 310, second inlet; 311, exhaust pipe; 312, collecting port; 313, narrow slit rectangular airway; 314, rectangular groove; 315, groove wall; 316, second high-pressure branch pipe; 317, third inlet; 318, fourth inlet;

[0039] 04-semi-open O-shaped protection device; 41. Compressed air intake pipe; 42. Air intake pipe pressure valve; 43. First hemispherical isolation cover; 44. Air distribution pipe; 45. Air knife; 46. High-pressure and high-speed air curtain; 47. Second hemispherical isolation cover; 48. Exhaust pipe; 49. Semi-cylindrical transparent enclosure;

[0040] 05-Rear iris diaphragm

[0041] 06-Workpiece

[0042] 07-Robotic Arm

[0043] 08- Air purification device; 81, one-way adsorption filter; 82, main exhaust pipe; 83, exhaust fan;

[0044] 84. Multi-layer filter element; 85. Exhaust vent; DETAILED DESCRIPTION

[0045] In order to make the present invention more clearly described, the present invention is further described below in conjunction with embodiments and drawings, but the protection scope of the present invention should not be limited thereto.

[0046] See also Figure 1 , Figure 1 It is a structural schematic diagram of an embodiment of a unidirectional multi-stage air curtain purification protection device for impact strengthening of the present invention. As shown in the figure, a unidirectional multi-stage air curtain purification protection device for impact strengthening includes a soundproof cover 01, and a front variable aperture 02 arranged in sequence along the laser transmission direction in the soundproof cover 01, four three-way unidirectional air curtain generators 03 distributed along the laser transmission direction, a semi-open O-shaped protection device 04, a rear variable aperture 05, a workpiece 06, a six-axis robot arm 07 for controlling the movement of the workpiece 06, an air purification device and an external water supply device, a water supply pipe, a water flow regulating valve, a clamp, and a water tank.

[0047] The overall working principle is as follows: the inlet pressure of the purified compressed air is adjusted so that the ends of the two parallel air knives in the semi-open O-shaped protection device form the first-stage high-pressure and high-speed air curtain, which blocks most of the sputtered water droplets and particulate dust generated during laser shock intensive processing in the second hemispherical isolation cover in the semi-open O-shaped protection device and enters the purification device through the exhaust pipe; the second-stage high-pressure and high-speed air curtain is formed by connecting more than two three-way one-way air curtain generators in series; the purified compressed air is split from the top to form the first and second high-pressure airflows and low-pressure airflows, respectively. The two high-pressure airflows pass through the first and second high-pressure branch pipes, and are divided into The optical axis cavity is respectively introduced from inlet 1, inlet 3, inlet 2 and inlet 4; the low-pressure airflow enters the narrow slit rectangular airway with a groove structure, and merges with two high-pressure airflows at the intersection of the optical axis cavity and the airway to form turbulence, generating a high-pressure and high-speed air curtain from top to bottom; the sputtered water droplets and particle dust that enter the optical axis cavity after passing through the first-stage air curtain are quickly taken away and enter the collection port at the lower end of the three-way one-way air curtain generator, and enter the air purification device after passing through the exhaust pipe; by adopting the above two-stage air curtain, the water droplets and particle dust that splash back into the optical path during laser shock intensive processing can be completely isolated, thereby protecting the lenses in the optical path from damage.

[0048] Figure 2 It is a structural schematic diagram of the three-way one-way air curtain generator in the present invention, as shown in the figure,

[0049] The three-way one-way air curtain generator 03 generates a high-pressure and high-speed air curtain to block the water droplets and particle dust splashed back in the opposite direction of the light beam. Its structure includes:

[0050] The body 30 has an optical axis cavity 31 therein for light beam transmission;

[0051] A gas splitter 33 is provided on the body 30 and is used to divide the gas flow input from the gas inlet pipe 32 into three paths: a first high-pressure gas flow 34, a low-pressure gas flow 35 and a second high-pressure gas flow 36;

[0052] An air inlet pipe 32 connected to a gas diverter 33 for inputting purified compressed air;

[0053] Two inclined inlets, the first inlet 39 and the second inlet 310, are provided on the main body 30 along the upper and lower axes, respectively, and two inclined inlets, the third inlet 317 and the fourth inlet 318, are provided along the left and right axes, respectively, and these inlets allow high-pressure airflow to enter the optical axis cavity 31. Among them, the first high-pressure airflow 34 is divided into two paths through the first high-pressure branch pipe 37 and the one-to-two air pipe, respectively, and enters the optical axis cavity 31 through the first inlet 39 and the second inlet 310; the second high-pressure airflow 36 is divided into two paths through the second high-pressure branch pipe 316 and the one-to-two air pipe, respectively, and enters the optical axis cavity 31 through the third inlet 317 and the fourth inlet 318; the two high-pressure airflows are transmitted in the optical axis cavity 31 in the same direction and in the opposite direction along the laser transmission direction;

[0054] The narrow slit rectangular airway 313 is connected to the bottom of the low-pressure airflow 35, and is formed by alternating rectangular grooves 314 and groove walls 315 evenly distributed in the two long side walls; and the rectangular grooves 314 and groove walls 315 are symmetrical along the center line of the narrow slit rectangular airway 313, so that one low-pressure airflow 35 forms turbulence through the narrow slit rectangular airway 313, and converges with the two high-pressure airflows to form a high-pressure and high-speed air curtain, which penetrates the optical axis cavity 31, thereby blocking the water droplets and particulate dust splashed back in the opposite direction of the light beam, and enters the air purification device after passing through the collection port 312 and the exhaust pipe 311 along the bottom of the narrow slit rectangular airway 313, such as Figure 3 shown.

[0055] Figure 4 Schematic diagram of the structure of the semi-open O-shaped protective device in the present invention. As shown in the figure, the semi-open O-shaped protective device 04 includes:

[0056] The first hemispherical isolation cover 43 is located above the light path and plays a role of isolation and protection.

[0057] The second hemispherical isolation cover 47 is located below the optical path and corresponds to the first hemispherical isolation cover 43 , and together they form a semi-open protective space.

[0058] The semi-cylindrical transparent enclosure 49 connects the first hemispherical isolation cover 43 and the second hemispherical isolation cover 47 to form a complete semi-open protection structure. The transparent enclosure ensures that the light path is unobstructed.

[0059] At least two air knives 45 are fixed in parallel in the first hemispherical isolation cover 43 and are connected to the purified compressed air supply device through the compressed air inlet pipe 41 and the pressure valve 42, thereby forming a first-stage high-pressure air curtain 46.

[0060] The purified compressed air supply device provides purified compressed air to the air knife 45 through the compressed air inlet pipe 41 and the pressure valve 42. The air knife 45 sprays the purified compressed air onto the optical path to form a first-stage high-pressure air curtain 46, thereby preventing external impurities, dust, etc. from entering the optical path and protecting the cleanliness and stability of the optical path.

[0061] The workflow is as follows:

[0062] Step 1. Workpiece preparation and six-axis robot arm program setting:

[0063] Fix the workpiece 06 on the fixture; according to the position of the center hole of the rear variable aperture 05, the position and size of the area to be impacted on the surface of the workpiece 06, the height and position of the water tank, and the posture and position of the six-axis robot 07, set and edit the control program of the motion trajectory and origin position of the six-axis robot 07 during the laser shock peening process to ensure that the motion frequency of the six-axis robot 07 and the repetition rate of the laser beam are synchronized.

[0064] Step 2. Adjustment and alignment of the laser beam:

[0065] After the external laser is started, the unidirectional multi-stage air curtain purification protection device is adjusted to ensure that the laser beam 01 can pass through the front variable aperture 02, the three-way unidirectional air curtain generator 03, the circular hole of the semi-open O-shaped protection device 04, and the rear variable aperture 05, and finally projected onto the surface area to be impacted of the workpiece 06; by adjusting the posture and position of the six-axis robot 07, the surface of the workpiece 06 coincides with the focal plane of the laser beam, and the surface of the workpiece 06 is perpendicular to the central axis of the laser beam.

[0066] Step 3. Configuration of water supply system:

[0067] According to the position and size of the area to be impacted on the surface of the workpiece 06, the projection position of the laser beam, the height and position of the water tank, and the posture and position of the six-axis robot 07, the position and posture of the water supply pipe are adjusted; the water supply system is turned on, and the water flow regulating valve is adjusted so that the thickness of the laminar inhibition layer formed in the area to be impacted on the surface of the workpiece 06 is between 0.5 and 2 mm, and the optimal thickness is 1 mm.

[0068] Step 4. Purify the compressed air supply and adjust the air pressure:

[0069] Start the purified compressed air supply device and adjust the air pressure valve of the air intake pipe to maintain the air pressure of the purified compressed air first air intake pipe 41 and the air intake pipe 32 at 0.4 MPa to 1.4 MPa, with the optimum air pressure being 0.8 MPa.

[0070] Step 5. Adjustment of the semi-open O-ring protector:

[0071] The heights of the first hemispherical isolation cover 43, the second hemispherical isolation cover 47 and the air knife 45 in the semi-open O-shaped protection device 04 are adjusted to control the distance between the air outlet of the air knife 45 and the laser beam to be 5 mm to 50 mm, with the optimal distance being 10 mm. At the same time, the orientation of the air knife 45 and the semi-cylindrical transparent enclosure 49 is adjusted to ensure that the maximum plane of the air knife 45 and the two vertical side planes of the semi-cylindrical transparent enclosure 49 are parallel to the surface of the workpiece 06.

[0072] Step 6. Start-up of laser shock peening and air purification device:

[0073] The motion control program of the six-axis robot 07 is started to synchronize its motion rhythm with the light emission frequency of the laser beam, thereby performing laser shock strengthening on the surface of the workpiece 06.

[0074] The air purification device is started synchronously, and the exhaust fan 83 draws the airflow in the exhaust pipe 311 of the multi-stage three-way one-way air curtain system and the exhaust pipe 48 of the second hemispherical isolation cover 47, as well as the gas inside the sealed sound insulation cover 28 into the main exhaust pipe 82, and filters them through the one-way adsorption filter 81 and the multi-layer filter element 84, and finally discharges them from the exhaust port 85.

[0075] During the laser shock peening process, this embodiment can effectively protect the lens in the optical path from the adhesion of water droplets and particle dust sputtered by the laser-induced shock wave, thereby avoiding damage to the lens. The laser energy projected onto the target surface has almost no loss, ensuring the consistency and stability of the laser energy, thereby improving the processing effect and quality of the laser shock peening of the workpiece, increasing the working efficiency of the device, extending the service life of the system, reducing the laser shock peening cost of the workpiece, and protecting the processing environment and the safety of the operator.

[0076] The above description only illustrates one embodiment of the present invention, which is relatively specific and detailed, but cannot be understood as limiting the scope of the present invention. It should be noted that, for ordinary technicians in this field, any form of modification can be made without departing from the concept of the present invention. Therefore, the protection scope of the present invention should be based on the attached claims.

Claims

1. A unidirectional multi-stage air curtain purification protection device for laser shock peening, comprising an air purification device, a soundproof cover (01), and a front variable aperture (02), a rear variable aperture (05), a workpiece (06) and a six-axis robot arm (07) for controlling the movement of the workpiece (06) arranged in sequence in the soundproof cover (01) along the laser transmission direction, characterized in that: It also includes at least two three-way one-way air curtain generators (03) distributed along the laser transmission direction and a semi-open O-shaped protection device (04); The three-way one-way air curtain generator (03) generates a high-pressure and high-speed air curtain to block water droplets and particle dust splashed back in the opposite direction of the light beam, and comprises: A body (30) having an optical axis cavity (31) therein for light beam transmission; A gas flow divider (33) is arranged on the body (30) and is used to divide the air flow input from the air inlet pipe (32) into three paths: a first high-pressure air flow (34), a low-pressure air flow (35) and a second high-pressure air flow (36); An air inlet pipe (32) connected to the gas diverter (33) for inputting purified compressed air; Two inclined inlets, a first inlet (39) and a second inlet (310), are respectively provided on the body (30) along the upper and lower axes, and two inclined inlets, a third inlet (317) and a fourth inlet (318), are respectively provided along the left and right axes; the first high-pressure airflow (34) is divided into two paths through the first high-pressure branch pipe (37) and the one-to-two air pipe, and enters the optical axis cavity (31) through the first inlet (39) and the second inlet (310); the second high-pressure airflow (36) is divided into two paths through the second high-pressure branch pipe (316) and the one-to-two air pipe, and enters the optical axis cavity (31) through the third inlet (317) and the fourth inlet (318); the two paths of high-pressure airflow are respectively transmitted in the optical axis cavity (31) in the same direction and in the opposite direction along the laser transmission direction; The narrow slit rectangular airway (313) is connected to the bottom of the low-pressure airflow (35), and is formed by alternating two rectangular grooves (314) and groove walls (315) uniformly distributed along the long side wall, and the rectangular grooves (314) and groove walls (315) are symmetrical along the center line of the narrow slit rectangular airway (313), so that one low-pressure airflow (35) forms turbulence through the narrow slit rectangular airway (313), and converges with the two high-pressure airflows to form a high-pressure and high-speed air curtain, which penetrates the optical axis cavity (31), thereby blocking water droplets and particle dust splashed back in the opposite direction of the light beam, and enters the air purification device after passing through the collection port (312) and the exhaust pipe (311) along the bottom of the narrow slit rectangular airway (313). The semi-open O-shaped protective device (04) comprises a first hemispherical isolation cover (43) and a second hemispherical isolation cover (47) respectively located on and below the optical path, and a semi-cylindrical transparent enclosure (49) connecting the first hemispherical isolation cover (43) and the second hemispherical isolation cover (47). At least two parallel air knives (45) are arranged in the first hemispherical isolation cover (43). The air knives (45) are connected to the purified compressed air supply device through a compressed air inlet pipe (41) and a pressure valve (42) to form a first-stage high-pressure and high-speed air curtain (46).

2. The one-way multi-stage air curtain purification protection device according to claim 1 is characterized in that: The ratio of the height of the groove wall (315) to the length of the rectangular groove (314) is 1:2 to 1:4, forming a microstructure that runs through the entrance to the exit of the narrow slit rectangular airway (313), thereby increasing the speed of the airflow flowing along the narrow slit rectangular airway (313).

3. The one-way multi-stage air curtain purification protection device according to claim 1 is characterized in that: The distance between the air outlet of the air knife (45) and the laser beam is adjustable within a range of 5 mm to 50 mm, and the orientation of the air knife (45) and the semi-cylindrical transparent enclosure (49) is adjustable to ensure that the maximum plane of the air knife (45) and the two vertical side planes of the semi-cylindrical transparent enclosure (49) are parallel to the surface of the workpiece (06).

4. The one-way multi-stage air curtain purification protection device according to claim 3 is characterized in that: The distance between the air outlet of the air knife (45) and the laser beam is 10 mm.

5. The one-way multi-stage air curtain purification protection device according to any one of claims 1 to 4, characterized in that: The air intake pipe (32) is externally connected to a purified compressed air supply device, and the air pressure is adjusted by an air pressure valve so that the air pressure in the compressed air intake pipe (41) is maintained between 0.4 MPa and 1.4 MPa.

6. The one-way multi-stage air curtain purification protection device according to any one of claims 1 to 4, characterized in that: The outer wall of the body (30) is provided with threaded holes, which are connected in pairs through connecting rods to form a second-stage high-pressure air curtain.

7. The one-way multi-stage air curtain purification protection device according to any one of claims 1 to 4, characterized in that: The air purification device comprises a main exhaust pipe (82), an exhaust fan (83), a multi-layer filter element (84) and an exhaust port (85), and the gas inside the soundproof cover (01) is sucked into the main exhaust pipe (82) through a one-way adsorption filter (81), and is filtered through the multi-layer filter element (84) and then discharged from the exhaust port (85), so as to suck and purify water droplets and particulate dust in the working space.

8. The one-way multi-stage air curtain purification protection device according to claim 1 is characterized in that: The purified compressed air in the semi-open O-shaped protective device (04) enters the compressed air intake pipe (41) from the purified compressed air supply device, and enters the air knife (45) through the intake pipe air pressure valve (42) and the air distribution pipe (44). The high-pressure airflow passes through the air knife (45) to form a first-level high-pressure and high-speed air curtain (46) to blow most of the water droplets and particulate dust splashed back during laser impact strengthening to the second hemispherical isolation cover (47). Under the combined action of the high-speed and high-pressure airflow and the suction from the exhaust pipe, the water droplets and particulate dust in the second hemispherical isolation cover (47) are brought to the main exhaust pipe (82), passed through the one-way adsorption filter, and then enter the air purification device for purification.

9. The one-way multi-stage air curtain purification protection device according to claim 1, characterized in that: The air pressures of the two high-pressure air flows are the same, and the air pressure ratio between the two high-pressure air flows and the remaining low-pressure air flow (35) is 1.5:1 to 6:

1.

10. The device according to any one of claims 1 to 9, characterized in that: The motion trajectory and control program of the six-axis robot arm are edited and set according to the position of the workpiece (06), the position of the water tank, the position of the laminar flow suppression layer and the position of the laser beam, so as to ensure that the motion frequency of the six-axis robot arm is synchronized with the repetition frequency of the laser beam, thereby achieving precise impact strengthening of the surface of the workpiece (06).

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