Laser peening processing method and device for generating laser peening restraint layer

Abstract

The invention aims to provide a laser peening processing method and a device for generating a laser peening restraint layer. The device for generating the laser peening restraint layer comprises a water tank, a water inlet pipe and a flow guide part. The water tank is provided with side walls and a bottom wall, one side wall is provided with an opening, and the opening is adjacent to the bottom wall. The water inlet pipe is communicated with the upper portion of the water tank, and the flow guide part is arranged on the outer side of the side wall corresponding to the opening so as to restrain and guide liquid flowing out of the opening. By means of the device for generating the laser peening restraint layer, the stability and the machining quality of laser peening strengthening machining can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of aviation manufacturing surface strengthening, and in particular to a laser shot peening method and a device for generating a laser shot peening constraining layer. Background Art

[0002] Laser shock peening, also known as laser shot peening, is a new laser surface treatment technology that uses a short pulse width (ns level) and high power density (>1GW / cm2) laser beam to act on the absorption layer of the metal target (usually black tape, black paint or aluminum foil is used as the absorption layer) to generate a high-pressure (>1Gpa) plasma shock wave constrained by a constrained layer (usually a flowing water film or K9 glass as a constrained layer), forming an instantaneous shock pressure load, causing local plastic deformation and grain refinement layer on the surface of the material, and obtaining residual compressive stress on the surface of the workpiece, thereby greatly improving the fatigue resistance and stress corrosion resistance of metal materials.

[0003] Laser shot peening is a new surface strengthening process technology that has emerged in recent decades. Compared with the traditional mechanical shot peening process, the laser shot peening area is controllable, a deeper compressive stress layer can be produced on the surface of the workpiece, and the effect on the roughness of the material surface is also small. Laser shot peening can significantly improve the surface properties of parts, such as increasing the surface hardness of parts, refining grains, improving the surface residual stress field, and reducing the extension of microcracks. In view of the above advantages of laser shot peening, laser shot peening can effectively improve the fatigue resistance of metal parts such as titanium alloy blades, and improve the corrosion resistance, foreign impact resistance and fatigue life of the workpiece material. In theory, the laser shot peening process is suitable for all parts made of metal that require fatigue resistance.

[0004] How to improve the stability and quality of laser shot peening processing is an urgent problem that needs to be solved. Summary of the invention

[0005] The object of the present invention is to provide a device for generating a laser shot peening constraining layer, which can improve the stability and processing quality of laser shot peening strengthening processing.

[0006] A device for generating a laser peening constrained layer to achieve the above-mentioned purpose comprises:

[0007] A water tank having side walls and a bottom wall, wherein one of the side walls is provided with an opening, and the opening is adjacent to the bottom wall;

[0008] a water inlet pipe connected to the upper portion of the water tank; and

[0009] The guide portion is arranged on the outer side of the side wall corresponding to the opening to restrict and guide the liquid flowing out of the opening.

[0010] In one or more embodiments, a baffle is provided on the inner wall of the water tank, the baffle is provided at the opening, and is movable from a first position to a second position along the height direction of the water tank;

[0011] When the baffle moves to the first position, the baffle avoids the opening; when the baffle moves to the second position, the baffle covers the opening; when the baffle moves between the first position and the second position, the size of the opening is adjusted.

[0012] In one or more embodiments, the guide portion includes an upper baffle and a lower baffle, the upper baffle and the lower baffle are respectively protruding from the side wall of the water tank, the lower baffle is arranged on the bottom wall of the opening, and the upper baffle is arranged in the opening and connected to the baffle.

[0013] In one or more embodiments, a tooth portion is provided on the side of the baffle facing the interior of the water tank, a gear is provided inside the water tank, the gear is meshed with the tooth portion, and an operating portion is provided outside the water tank, through which the gear can be driven to rotate, thereby driving the baffle to move along the height direction of the water tank.

[0014] In one or more embodiments, a stop portion is provided inside the water tank, and when the baffle moves to the first position, the stop portion abuts against the baffle.

[0015] In one or more embodiments, a frame is further included, on which a track and a slider movable along the track are disposed, and the water tank is connected to the slider.

[0016] In one or more embodiments, the water tank is connected to the slider via a telescopic rod.

[0017] In one or more embodiments, the water tank is connected to the end of the telescopic rod through a bearing, so that the water tank is rotatable relative to the telescopic rod with the axial direction of the telescopic rod as the rotation center.

[0018] In one or more embodiments, a filter is provided at the opening.

[0019] On the other hand, according to some embodiments of the present application, a laser shot peening method is also provided, which uses the device for generating a laser shot peening constraining layer as described above to generate a water film constraining layer on the surface of the workpiece during the processing;

[0020] The guide portion includes an upper baffle and a lower baffle, the upper baffle and the lower baffle are respectively protruding from the side wall of the water tank, the lower baffle is arranged on the bottom wall of the opening, and the upper baffle is arranged in the opening;

[0021] When the laser spot size during processing is 2 to 3.5 mm and the laser energy is 6 to 13 joules, in the device for generating a laser shot peening constraint layer, the volume of the water tank is 90 to 150 cubic millimeters, the width of the opening is 10 to 20 mm, the thickness of the water film flowing out of the opening is 1.5 to 3 mm, the upper baffle is arc-shaped, the arc radius of the upper baffle is 25 to 35 mm, the arc length is 8 to 12 mm, and the lower baffle is sloped with a slope of 10° to 15°; the water pressure of the water entering the water tank through the water inlet pipe is 0.08 to 0.15 MPa;

[0022] When the laser spot size during processing is between 3.5 and 8 mm and the laser energy is between 14 and 30 joules, in the device for generating a laser shot peening constraint layer, the volume of the water tank is between 150 cubic millimeters and 200 cubic millimeters, the width of the opening is between 15 and 25 mm, the thickness of the water film flowing out of the opening is between 2.5 and 5 mm, the upper baffle is arc-shaped, the arc radius of the upper baffle is between 35 and 40 mm, the arc length is between 12 and 16 mm, and the lower baffle is sloped with a slope of 10° to 15°; the water pressure of the water entering the water tank through the water inlet pipe is between 0.12 and 0.25 MPa.

[0023] The beneficial effects of the present invention are:

[0024] By using a device having this configuration for generating a laser shot peening constrained layer, the existing tubular constrained layer water flow is optimized by non-contact water discharge method of water pressure jetting into a top-down waterfall-like constrained layer water film covering method formed by a certain gravity. The water flow can flow down naturally from the opening under the action of gravity. Compared with the use of a nozzle and other forms that are prone to water splashing, the interference of water splashing and water mist on the laser optical path is reduced, thereby achieving control over the water film thickness, thereby improving the stability and processing quality of laser shot peening strengthening processing.

[0025] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0027] Figure 1 A schematic diagram showing an existing constrained layer water film generation method;

[0028] Figure 2 Schematic diagrams showing some embodiments of the apparatus for generating a laser peening confinement layer according to the present invention;

[0029] Figure 3 Shows a three-dimensional schematic diagram of some embodiments of the water tank;

[0030] Figure 4 A half-section schematic diagram of some embodiments of the water tank is shown;

[0031] Figure 5 A partial schematic diagram showing some embodiments of the apparatus for generating a laser peening confinement layer according to the present invention;

[0032] Figure 6 A schematic diagram showing the processing process of the device for generating a laser shot peening constraining layer according to the present invention. DETAILED DESCRIPTION

[0033] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0035] When laser shot peening is performed on parts, the factors that affect the shot peening effect of the parts, in addition to the inherent characteristics of the laser shot peening system itself, such as laser type, laser optical path structure, etc., the most important influencing factor is the setting of relevant process parameters during the laser shot peening process, such as laser energy, number of impacts, laser spot diameter, spot overlap rate, laser path planning, and the selection and state characteristics of the constraint layer and absorption layer materials.

[0036] Because the physical process of laser shot peening is very complicated, in addition to conventional process parameters such as laser energy, number of laser impacts, and spot overlap rate, the selection and state characteristics of the constraint layer material will also have a great impact on the stability and reliability of the laser shock strengthening process. When the workpiece is laser shot peened, the pulsed laser acts on the opaque absorption layer through the constraint layer, causing it to partially evaporate. The steam absorbs the remaining laser and produces a rapidly expanding plasma flow. The expanded plasma is confined between the surface of the part and the constraint layer, and a rapidly increasing high-pressure shock wave is generated. The laser-induced plasma shock wave has an impact effect on the surface of the target material. When the peak intensity of the shock wave is higher than the impact yield strength of the metal, the metal surface undergoes plastic deformation and yields, and a residual compressive stress layer of a certain depth is formed on the surface of the peened target material. The residual stress layer enhances the material surface's ability to resist fatigue and stress corrosion.

[0037] The types of constrained layers used in the laser shock peening process include flowing liquid water film, K9 optical glass or transparent materials such as silicone gel. Since the solid constrained layer using glass and other media is easily broken due to impact explosion, it is impossible to carry out continuous multiple impacts, and it is not convenient to clean and replace, which has many disadvantages in actual engineering applications. Compared with solid materials such as glass, liquid medium water (distilled water or deionized water) has the advantages of high breakdown threshold, automatic recovery, strong controllability and low cost. Therefore, flowing water film has developed into the most commonly used constrained layer material in the field of laser shock peening and laser shock forming. In the process of laser shock peening, the water film constrained layer will explode violently under the action of high-energy laser-induced plasma shock waves, and the explosion splash will also produce a large amount of water mist. In the study of the dynamic response of the constrained layer under the action of laser shock, it was found that the state and thickness of the constrained layer have a significant impact on the stability of the laser shock peening process and the shock peening effect.

[0038] Therefore, the uniformity and stability of the water film in the constrained layer are very important for ensuring the process quality of laser shock peening of the workpiece. The state of the constrained layer covering the surface of the laser shock peening part is also one of the important process parameters affecting the laser shot peening effect.

[0039] Figure 1A schematic diagram of the existing constrained layer water film generation method is shown. As shown in the figure, in the laser shock peening device using liquid water film as the constrained layer, a circular water pipe 91 is usually used as the constrained layer transmission carrier during laser shock peening. Water flows from the cylindrical water pipe in the form of a water jet to the surface of the workpiece to be strengthened 93, forming a layer of approximately elliptical water film 92 of a certain thickness. In the actual laser shock peening process, the water film sprayed from the nozzle to the surface of the workpiece is affected by factors such as nozzle shape, water pressure, spray distance, and workpiece angle. The shape and thickness of the water film constrained layer are not clearly defined and effectively controlled during the laser shock peening process.

[0040] Therefore, in view of the problems such as uneven thickness of the water film in the constrained layer formed by a single-tube nozzle, unstable flow rate, and weak controllability of the water film state during laser shock peening, on the one hand, according to some embodiments of the present application, a device for generating a laser shot peening constrained layer is provided. Figure 2 The schematic diagram of some embodiments of the device for generating a laser shot peening constrained layer according to the present invention is shown, which includes a water tank 1, a water inlet pipe 2 and a guide part 3. The water tank 1 has a side wall 11 and a bottom wall 12, wherein an opening 10 is provided on one of the side walls 11, and the opening 10 is adjacent to the bottom wall 12, so that the liquid flowing into the water tank 1 can flow out from the opening 10, and the water inlet pipe 2 is connected to the upper part of the water tank 1 to pass the liquid into the water tank 1 through the water inlet pipe 2, wherein, in the embodiment shown in the figure, the water inlet pipe 2 is connected to the side wall of the water tank 1, and the side wall where the water inlet pipe 2 is located is arranged opposite to the side wall where the opening 10 is located. In some other suitable embodiments, the water inlet pipe 2 can also be connected to the top wall of the water tank 1, for example. The guide part 3 is arranged on the outside of the side wall 11 corresponding to the opening 10, so as to constrain and guide the liquid flowing out of the opening 10, so as to avoid splashing of the liquid flowing out of the opening 10.

[0041] In the existing water film generation method, when the parts are subjected to laser shock strengthening, the thickness of the water film in the columnar constraint layer cannot be adjusted and the water film thickness cannot be accurately controlled. When the tubular water flow is sprayed onto the surface of the workpiece, splashing and turbulence are prone to occur.

[0042] By using the device for generating a laser shot peening constrained layer with this configuration, the existing tubular constrained layer water flow is optimized by non-contact water discharge method of water pressure jet to a top-down waterfall-like constrained layer water film covering method formed by a certain gravity. The water flow can flow down naturally from the opening 10 under the action of gravity. Compared with the use of a nozzle and other forms that are prone to water splashing, the interference of water splashing and water mist on the laser optical path is reduced, thereby achieving control over the water film thickness, thereby improving the stability and processing quality of laser shot peening strengthening processing.

[0043] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0044] Figure 3 shows a three-dimensional schematic diagram of some embodiments of the water tank, Figure 4 A half-section schematic diagram of some embodiments of the water tank is shown. In some embodiments of the device for generating a laser shot peening constraining layer, a baffle 4 is provided on the inner wall of the water tank 1. The baffle 4 is provided at the opening 10 and is movable from the first position to the second position along the height direction h of the water tank 1. When the baffle 4 moves to the first position, the baffle avoids the opening 10, that is, there is no obstruction at the opening 10 at this time. When the baffle 4 moves to the second position, the baffle 4 shields the opening 10 to prevent the liquid from flowing out of the opening 10. When the baffle 4 moves between the first position and the second position, the size of the opening 10 is adjusted. It can be understood that in some optional embodiments, the baffle 4 can be movably arranged in the water tank 1 by, for example, a slide rail. In the above manner, the size of the opening 10 is adjustable, which is more flexible than the traditional method of obtaining a water film by nozzle spraying, and the thickness of the water film constraining layer can be adjusted during the processing, further improving the processing efficiency and processing quality.

[0045] In some embodiments of the device for generating a laser shot peening constrained layer, the guide portion 3 includes an upper baffle 31 and a lower baffle 32, and the upper baffle 31 and the lower baffle 32 are respectively protruded from the side wall of the water tank 1 to guide and constrain the liquid. The lower baffle 32 is arranged on the bottom wall of the opening 10, that is, connected to the bottom wall of the water tank 1, and the upper baffle 32 is arranged in the opening 10 and connected to the baffle 4, so that when the baffle 4 moves along the height direction h of the water tank 1, the baffle 4 can also be driven to move synchronously along the height direction h. In a specific embodiment, the upper baffle 31 is an arc plate, the arc direction is upward, and the arc radius is R25~R40mm, and the lower baffle is a slope plate with an inclined upper surface and a slope of 10°~12°, so as to better guide and constrain the liquid. In a specific embodiment, the upper baffle 31 is connected to the bottom of the movable baffle 4, which has a certain restraining effect on the water flow. The lower baffle 32 is connected to the bottom of the water outlet of the water tank 1, which has a certain guiding effect on the water flow, so that the water flow falls heavily on the surface of the workpiece at a certain angle.

[0046] In a specific embodiment, the upper baffle 31 is longer than the lower baffle.

[0047] By having the opening 10 of the aforementioned guide portion 3, the water volume and water film thickness of the constrained layer can be effectively adjusted to form a constrained layer water film with a thickness range of 0 to 10 mm. When the workpiece is laser shot peening, the thickness of the water film can be adjusted and matched according to the intensity requirements of the shot peening, so that the water film thickness is more matched with the laser energy during the shot peening process, so that the workpiece can obtain a better shot peening effect, and the constrained layer process parameters that affect the shot peening effect are more operable and controllable.

[0048] In some embodiments of the device for generating a laser shot peening constrained layer, a tooth portion 41 is provided on the side of the baffle 4 facing the inside of the water tank, a gear 42 is provided inside the water tank, the gear 42 is meshed with the tooth portion 41, and an operating portion 13 is provided outside the water tank 1, and the gear 42 can be driven to rotate by the operating portion 13 to drive the baffle 4 to move along the height direction h of the water tank. In some specific embodiments, the operating portion 13 is a hand wheel, which is connected to the gear 42 through a transmission shaft.

[0049] In some embodiments of the device for generating a laser shot peening constraining layer, a stopper 43 is provided inside the water tank. When the baffle 4 moves to the first position, the stopper 43 abuts against the baffle 4 to limit it, so as to prevent the baffle 4 from excessive movement.

[0050] In some embodiments of the device for generating a laser shot peening constraining layer, a frame 5 is further included. The frame 5 is provided with a track 51 and a slider 50 movable along the track. The water tank 1 is connected to the slider 50, so that when the slider 50 moves along the track 51, the water tank 1 can be driven to move synchronously. In a specific embodiment, the slider 50 is a pulley. In a specific embodiment, the frame 5 is a bracket on the ceiling of the laser shot peening room.

[0051] In some embodiments of the device for generating a laser shot peening constraining layer, the water tank 1 is connected to the slider via a telescopic rod 52. By extending and retracting the telescopic rod 52, the height position of the water tank 1 can be changed to adapt to different processing scenarios. In a specific embodiment, a first locking portion 53 is provided on the telescopic rod 52, and the first locking portion 53 can be, for example, a bolt, through which the telescopic rod 52 can be restricted from being extended and retracted, thereby limiting the water tank 1 at a specified position.

[0052] Because the pulse laser light path of the laser shot peening equipment is fixed, the shot peening process of the parts is completed by the robot holding the workpiece and completing the shot peening process through relative movement with the fixed pulse laser focus. Through the above-mentioned method, the distance between the water tank 1 and the workpiece can be adjusted by moving the position of the slider 50, and the telescopic rod 52 can adjust the height of the water tank 1, and cooperate with the slider 50 to keep the water outlet of the water constraint layer at a suitable position.

[0053] Figure 5 A partial schematic diagram of some embodiments of the device for generating a laser shot peening constraining layer according to the present invention is shown. In some embodiments of the device for generating a laser shot peening constraining layer, the water tank 1 is connected to the end of the telescopic rod 52 through a bearing 54, so that the water tank 1 can rotate relative to the telescopic rod 52 with the axial direction of the telescopic rod 52 as the rotation center, thereby being able to change the orientation of the opening 10 to adapt to different processing scenarios. In a specific embodiment, the water tank 1 is connected to the bearing 54 through an adapter 14, the inner ring of the bearing 54 is fixed to the end of the telescopic rod 52, and the adapter 14 is fixed to the outer circumference of the outer ring of the bearing 54. In some specific embodiments, the water tank 1 and the adapter 14 are connected by threads. In a specific embodiment, an angular limiting flange 6 is also provided between the adapter 14 and the telescopic rod 52, the angular limiting flange 6 is sleeved on the telescopic rod 52, and the lower end of the angular limiting flange 6 is connected to the adapter 14, which is used to fix the angular position of the constraining layer water tank 14. When the angular position of the constraining layer outlet is adjusted appropriately, the angular position can be adjusted and fixed by the angular second locking portion 61 on the angular limiting flange 6, wherein the second locking portion can also be a locking bolt.

[0054] In a specific embodiment, the water tank 1 is a rectangular parallelepiped structure, and a vent plug 15 is arranged on the top. The vent plug 15 is opened when filling with water and closed after being filled with water.

[0055] In a specific embodiment, the operating portion 13 may be provided with a scale to display the adjusted height position of the baffle 4 .

[0056] In a specific embodiment, a scale 16 is provided on the side wall of the water tank 1 to display the height position of the upper baffle 31 and the baffle plate 4 connected thereto in the water tank.

[0057] In some embodiments of the device for generating a laser shot peening constrained layer, a filter is provided at the opening 10. Specifically, the filter is an 80-mesh or 120-mesh filter, which plays a role in making the water flow at the outlet smooth and stable, and makes the water flow form a laminar flow effect, effectively reducing the damage to the water film caused by the splashing and impact of the water flow when the water flow is sprayed onto the surface of the workpiece, making the water film covering the shot peening strengthening area more stable and more uniform in thickness.

[0058] In some embodiments of the apparatus for generating a laser shot peening constraining layer, the water tank is formed by processing materials such as polyethylene plastic or aluminum alloy metal.

[0059] In some embodiments of the device for generating a laser shot peening constrained layer, the length, width and height ratio of the water tank 1 (the water outlet is located at the wide side of the water tank) is set at about 1.5:1:3 or 1.2:1:3, ensuring that the water tank has sufficient height so that the water flow at the outlet of the constrained layer has a certain deadweight, forming a "waterfall" type water flow. The width of the water tank outlet can be determined according to the laser shot peening spot diameter and the workpiece size. In a specific embodiment, when the processed spot diameter is 1.5mm to 3.5mm, the width of the outlet can be designed to be between 10mm and 20mm, preferably 15mm. When the laser spot diameter is larger, the width of the outlet and the water flow rate can also be appropriately increased.

[0060] On the other hand, according to some embodiments of the present application, a laser shot peening method is also provided, which uses the device for generating a laser shot peening constraining layer as described in one or more embodiments described above to generate a water film constraining layer on the surface of the workpiece during the processing;

[0061] The guide part 3 includes an upper baffle 31 and a lower baffle 32, the upper baffle 31 and the lower baffle 32 are respectively protruded from the side wall of the water tank, the lower baffle 32 is arranged on the bottom wall of the opening 10, and the upper baffle 31 is arranged in the opening;

[0062] When the laser spot size during processing is between 2 and 3.5 mm and the laser energy is between 6 and 13 joules, in the device for generating a laser shot peening constrained layer, the volume of the water tank 1 is between 90 cubic millimeters and 150 cubic millimeters, the width of the opening 10 is between 10 and 20 mm, the height of the opening 10 is between 1.5 and 3 mm, the upper baffle 31 is arc-shaped, the arc radius of the upper baffle 31 is between 25 and 35 mm, the arc length is between 8 and 12 mm, and the lower baffle 32 is sloped with a slope of 10° to 15°; the water pressure of the water entering the water tank through the water inlet pipe is between 0.08 and 0.15 MPa; in this embodiment, specifically, the aspect ratio of the water tank 1 is 1.5:1:2.8.

[0063] When the laser spot size during processing is 3.5 to 8 mm and the laser energy is 14 to 30 joules, in the device for generating the laser shot peening constrained layer, the volume of the water tank 1 is 150 to 200 cubic millimeters, the width of the opening 10 is 15 to 25 mm, the height of the opening 10 is 2.5 to 5 mm, the upper baffle 31 is arc-shaped, the arc radius of the upper baffle 31 is 35 to 40 mm, the arc length is 12 to 16 mm, and the lower baffle 32 is sloped with a slope of 10° to 15°; the water pressure of the water entering the water tank 1 through the water inlet pipe 2 is 0.12 to 0.25 MPa. In this embodiment, specifically, the aspect ratio of the water tank 1 is 1.2:1:3.

[0064] Specifically, in the embodiment described herein, the width of the opening 10 is the dimension along the bottom wall 12 , and the thickness of the water film flowing out of the opening 10 can be limited by changing the height of the opening 10 or changing the height of the baffle 4 at the opening 10 .

[0065] Through the device for generating a laser shot peening constraint layer described in one or more of the aforementioned embodiments, the water film constraint layer is changed from the previous single-tube injection method to a constraint layer providing system composed of a slide rail, an adapter, a water tank and other components. The new constraint layer device can conveniently and efficiently adjust the position of the water film of the constraint layer in a larger spatial range. The front and rear distance of the constraint layer outlet can be quickly adjusted through the top slide rail, and the angular position of the constraint layer outlet can be adjusted through the water tank connection plate, which greatly improves the flexibility and freedom of adjusting the position of the constraint layer outlet during laser shot peening.

[0066] Compared with the single-tube constraint layer nozzle, the device for generating laser shot peening constraint layer can effectively control the water volume and water film thickness of the constraint layer, and transform the uncontrollable influencing factor of laser shot peening constraint layer into a process parameter with certain operability and controllability. The water film thickness can be adjusted and matched according to the requirements of shot peening, giving full play to the role of the constraint layer water film during laser shot peening, and at the same time, it is beneficial to control the deformation degree of the workpiece during shot peening and improve the laser shot peening effect.

[0067] Compared with the water film of the constrained layer formed by a single-tube nozzle jet impacting the area to be strengthened, the water film formed by the device for generating the laser shot peening constrained layer has a larger coverage range and an adjustable water film thickness. The water film covers the area to be shot peened in a tangential manner in the form of a "waterfall", and the impact splashes and splashes are small. The constrained layer water film is more uniform and stable, and has little interference with the laser light path and scattering effect, which is more conducive to the laser shot peening process.

[0068] The device for generating a laser shot peening constraint layer, under the action of gravity and the water outlet filter, makes the water flow smoother and produces a certain laminar flow, so that the water film becomes more uniform and stable, meets the requirements for the spreading morphology of the water film during laser shock strengthening, and helps to improve the process quality of laser shot peening strengthening.

[0069] Compared with a single-tube nozzle, the device for generating a laser shot peening constraint layer has a convenient adjustment process. The outlet position of the constraint layer water film is adjusted by a slide rail and a water tank connecting plate to achieve the distance and angle adjustment with respect to the workpiece. This not only provides a larger size adjustment space, but also enables the outlet position to be adjusted with multiple degrees of freedom, such as up and down, front and back, left and right, and angular directions. The positional relationship with the workpiece is more accurate, and the measurability and repeatability are better, which can better meet the laser shot peening strengthening needs of parts in different states.

[0070] Figure 6 A schematic diagram showing the processing of the device for generating a laser peening constrained layer according to the present invention is shown in FIG. Figures 4 to 6 The processing of the device for generating the laser shot peening constrained layer is further described as follows:

[0071] Step 1: Before laser shot peening the workpiece 81, first clamp the workpiece 81 on the robot arm 82 and move the workpiece to the initial position for shot peening.

[0072] Step 2: Adjust the movable slider 50 to keep a suitable distance between the water tank 1 and the workpiece in the horizontal direction. The horizontal distance from the water tank 1 to the shot peening area of ​​the workpiece is usually determined based on the water pressure, water flow, water tank volume and the size characteristics of the water outlet of the water tank.

[0073] Step 3: Adjust the telescopic rod 52 to roughly adjust the water tank 1 to a suitable height range. Subsequently, the vertical distance between the water outlet position of the water tank 1 and the workpiece can be precisely adjusted according to the actual situation of the water flow covering the workpiece. Steps 2 and 3 can be interchanged.

[0074] Step 4: According to the characteristics of the area to be shot peened, the angular relationship between the water tank outlet and the workpiece 81 can be adjusted by rotating the water tank adapter 14 as needed. After the angular position is determined, the universal angular fastening screws can be used to fix it.

[0075] Step 5: Turn the operating part 13 , close the movable baffle 4 , open the air release plug 15 , and fill the water tank 1 with water.

[0076] Step 6: When the water tank 1 is filled with water, open the movable baffle 4 and screw on the vent plug 15.

[0077] Step 7: Select a suitable water film thickness according to the laser energy and process parameter characteristics during laser shot peening. The water film thickness can be adjusted by rotating the operating part 13. The device can provide a water film thickness of 0 to 10 mm.

[0078] Step 8: According to the water flow state at the water tank outlet, fine-tune the movable slider 50 again, adjust the telescopic rod 52 and the adapter 14 according to the actual situation, so that the water flow covers the surface of the workpiece to be shot peened in the best form.

[0079] Step 9: After the water flow state and position are adjusted, adjust the fastening of each component and start the formal laser peening process.

[0080] According to the different characteristics of laser shot peening equipment such as laser energy and spot size, water tanks 1 of different sizes can be designed and used, and appropriate water pressure can be selected to form an ideal "waterfall" type water confinement layer water film. The wall thickness of the water tank 1 is 0.8 to 1.5 mm.

[0081] Before laser shot peening is performed on the workpiece, the water tank is moved to the top of the area to be strengthened and kept at a distance of 100mm to 150mm from the area to be strengthened of the workpiece in the horizontal direction. The water film thickness adjustment operation unit 13 of the water tank is used to adjust the water film thickness at the water tank outlet to 3mm, and then the water tank distance is fine-tuned to make the water flow at the water tank outlet form a waterfall, so that the water flow contacts the area to be strengthened of the workpiece, and forms a stable and uniform constrained layer water film.

[0082] In order to obtain better laser shock peening effect. When a larger laser energy (greater than 13J) is used for laser shock peening, the water film thickness and water pressure can be set slightly larger, and the water film thickness can be set to 3mm~5mm. On the contrary, when the selected laser energy capacity is smaller, a thinner water film thickness can be selected. In this way, it can fully ensure that the water film stably and continuously covers the shot peening area, and at the same time, the water film can play a more sufficient and effective role in restraining the laser shock wave, which is conducive to improving the process quality of shot peening.

[0083] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "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 an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A device for generating a laser peening confinement layer, It is characterized in that include: A water tank having side walls and a bottom wall, wherein one of the side walls is provided with an opening, and the opening is adjacent to the bottom wall; a water inlet pipe connected to the upper portion of the water tank; as well as The guide portion is arranged on the outer side of the side wall corresponding to the opening to restrict and guide the liquid flowing out of the opening.

2. The device for generating a laser peening confinement layer according to claim 1, It is characterized in that The inner wall of the water tank is provided with a baffle, which is arranged at the opening and can move from a first position to a second position along the height direction of the water tank; When the baffle moves to the first position, the baffle avoids the opening; when the baffle moves to the second position, the baffle covers the opening; when the baffle moves between the first position and the second position, the size of the opening is adjusted.

3. The device for generating a laser peening confinement layer according to claim 2, It is characterized in that The guide portion includes an upper baffle and a lower baffle, the upper baffle and the lower baffle are respectively protruding from the side wall of the water tank, the lower baffle is arranged on the bottom wall of the opening, and the upper baffle is arranged in the opening and connected to the baffle.

4. The device for generating a laser peening confinement layer according to claim 2, It is characterized in that A tooth portion is provided on one side of the baffle plate facing the inside of the water tank, a gear is provided inside the water tank, the gear meshes with the tooth portion, and an operating portion is provided outside the water tank, through which the gear can be driven to rotate, so as to drive the baffle plate to move along the height direction of the water tank.

5. The device for generating a laser peening confinement layer according to claim 4, It is characterized in that A stopper is provided inside the water tank, and when the baffle moves to the first position, the stopper abuts against the baffle.

6. The device for generating a laser peening confinement layer according to claim 1, It is characterized in that The utility model also comprises a frame body, on which a track and a sliding block movable along the track are arranged, and the water tank is connected to the sliding block.

7. The device for generating a laser peening confinement layer according to claim 6, It is characterized in that The water tank is connected to the sliding block via a telescopic rod.

8. The device for generating a laser peening confinement layer according to claim 7, It is characterized in that The water tank is connected to the end of the telescopic rod through a bearing, so that the water tank can rotate relative to the telescopic rod with the axial direction of the telescopic rod as the rotation center.

9. The apparatus for generating a laser peening confinement layer according to claim 1, It is characterized in that A filter screen is arranged at the opening.

10. A laser shot peening method, It is characterized in that Using the device for generating a laser shot peening constraining layer as claimed in any one of claims 1 to 9 to generate a water film constraining layer on the surface of a workpiece during processing; The guide portion includes an upper baffle and a lower baffle, the upper baffle and the lower baffle are respectively protruding from the side wall of the water tank, the lower baffle is arranged on the bottom wall of the opening, and the upper baffle is arranged in the opening; When the laser spot size during processing is 2 to 3.5 mm and the laser energy is 6 to 13 joules, in the device for generating a laser shot peening constraint layer, the volume of the water tank is 90 to 150 cubic millimeters, the width of the opening is 10 to 20 mm, the thickness of the water film flowing out of the opening is 1.5 to 3 mm, the upper baffle is arc-shaped, the arc radius of the upper baffle is 25 to 35 mm, the arc length is 8 to 12 mm, and the lower baffle is sloped with a slope of 10° to 15°; the water pressure of the water entering the water tank through the water inlet pipe is 0.08 to 0.15 MPa; When the laser spot size during processing is 3.5 to 8 mm and the laser energy is 14 to 30 joules, in the device for generating a laser shot peening constraining layer, the volume of the water tank is 150 to 200 cubic millimeters, the width of the opening is 15 to 25 mm, the thickness of the water film flowing out of the opening is 2.5 to 5 mm, the upper baffle is arc-shaped, the arc radius of the upper baffle is 35 to 40 mm, the arc length is 12 to 16 mm, and the lower baffle is sloped with a slope of 10° to 15°; The water pressure of the water entering the water tank through the water inlet pipe is 0.12 to 0.25 MPa.

Images