Complex Freeform Surface Laser Jet-Assisted Conformal Microfabrication Device and Method

Abstract

The present invention provides a complex free-form surface laser jet-assisted conformal microfabrication device and method, belonging to the technical field of laser processing. It mainly includes a marble platform, a gantry support, an X slide, a Y slide, a Z slide, three groups of variable-line reflectors, a laser processing unit, a water jet unit, and a bus control system. The present invention makes full use of the jet-assisted conformal nozzle to accurately position the workpiece after laser processing and scour it with non-directional water flow, solving problems such as directional heat accumulation and slag accumulation in a single direction.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision special processing, and in particular relates to a device and method for laser jet-assisted conformal micro-processing of complex free-form surfaces. Background Art

[0002] In the field of mechanical processing, ultrashort pulse laser processing technology, while offering high precision and minimal thermal damage, suffers from issues such as low processing efficiency and poor kerf parallelism. Water jet-assisted laser technology can overcome these shortcomings by evenly transmitting laser energy within the water jet, reducing the kerf angle, improving processing accuracy, narrowing the heat-affected zone, and minimizing cracks and debris. However, this process is currently primarily used for small, flat workpieces and is less commonly used for machining complex free-form surfaces.

[0003] The closest prior art to the present invention is application number 201810325364.5, entitled "A Laser-Water Jet Composite Processing System." Existing water jet-assisted laser processing devices utilize the high energy of the laser and the cooling and cleaning effects of the water jet, offering certain advantages in improving processing precision and efficiency. This advantage lies in the ability to effectively integrate the laser and water jet, achieving a more efficient processing process. However, the currently used water jet nozzles limit the application scope of this technology. First, due to the complex and varied shapes of complex free-form surfaces, the curvature and other geometric features at each point vary significantly, making it difficult to ensure that the laser beam and water jet work together at the optimal angle and parameters at each processing position during the processing. Second, a large amount of heat is generated during laser processing, and current nozzles make it difficult to achieve uniform cooling of the workpiece, thus affecting processing quality. Furthermore, current nozzles have limited cleaning effectiveness on the surface of the processed workpiece. Impurities such as residual waste residue may not be completely removed.

[0004] In summary, existing laser processing devices have obvious deficiencies in complex free-form surfaces and other aspects, and there is an urgent need for a complex free-form surface laser jet-assisted conformal micromachining device and method to solve these problems. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a device and method for laser jet-assisted conformal micromachining of complex free-form surfaces. By using a jet-assisted conformal nozzle, the workpiece after laser processing is precisely positioned and flushed with non-directional water flow, thereby solving problems such as directional heat accumulation and slag accumulation in a single direction.

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

[0007] A complex free-form surface laser jet-assisted conformal micro-machining device, including a marble platform, on which a gantry bracket is fixedly arranged, and an X slide is fixedly arranged on the gantry bracket. The slider of the X slide is fixedly connected to a breadboard through an X slide adapter plate. A laser processing unit and a water jet unit are arranged on the breadboard;

[0008] A Y slide is also fixedly arranged on the marble platform below the X slide. The slider of the Y slide is fixedly connected to a Z slide through a Y slide adapter plate, and the slider of the Z slide is fixedly connected to a protective cover through a Z slide adapter plate;

[0009] A loading platform is fixedly arranged inside the protective cover, and a workpiece fixture for fixing the workpiece to be processed is fixedly arranged on the loading platform;

[0010] The laser processing unit includes a laser, a first deformable mirror, a second deformable mirror, a third deformable mirror, and a focusing mirror. The focusing mirror is fixedly connected below the third deformable mirror. Light guide tubes are arranged between the laser and the first deformable mirror, between the first deformable mirror and the second deformable mirror, and between the second deformable mirror and the third deformable mirror;

[0011] The water jet unit includes a nozzle fixing mechanism and a jet-assisted conformal nozzle mechanism. The nozzle fixing mechanism includes a nozzle manual slide and a nozzle two-way manual slide. One end of the nozzle manual slide is bolted to the breadboard, and the other end is fixedly connected to the top of the nozzle two-way manual slide through a connecting plate. The bottom of the nozzle two-way manual slide is bolted to the jet-assisted conformal nozzle mechanism through a manual slide adapter plate. The position of the jet-assisted conformal nozzle mechanism can be adjusted in three mutually perpendicular directions through the nozzle manual slide and the nozzle two-way manual slide;

[0012] It also includes a bus control system, which is communicatively connected to the first deformable mirror, the second deformable mirror, the third deformable mirror, the X slide, the Y slide, the Z slide, and the jet-assisted conformal nozzle mechanism.

[0013] Further, the jet-assisted conformal nozzle mechanism includes a bearing end cover, a rolling bearing, a bushing, a connection key, a turntable, a carrier, a nozzle fixture, a rotating shaft, a motor base, a rotating shaft coupling, a rotating shaft motor, a turntable motor, a turntable coupling, a motor connecting plate, a nozzle connecting rod, and a nozzle. The motor shaft of the turntable motor is connected to the turntable drive shaft through the turntable coupling. The turntable motor is fixed on the motor connecting plate. The turntable and the motor connecting plate are connected to the manual slide adapter plate through mounting holes and bolts. The carrier is fixedly connected to the output rotating shaft of the turntable. The bearing end cover is connected to the carrier by threads and is used to limit the movement of the rolling bearing. The rolling bearing is used to reduce the friction and wear of the rotating shaft. The nozzle fixture is connected to the rotating shaft through the connection key and can rotate with the rotating shaft. The bushing and the shaft shoulder of the rotating shaft jointly limit the nozzle fixture. The nozzle and the nozzle connecting rod are connected together by nuts. The nozzle connecting rod is fixed on the nozzle fixture. The motor base is connected to the carrier by bolts. The rotating shaft motor is connected to the motor base through a long screw. The motor shaft of the rotating shaft motor is connected to the rotating shaft through the rotating shaft coupling. Both the rotating shaft motor and the turntable motor are communicatively connected to the bus control system.

[0014] A complex free-form surface laser jet-assisted conformal micro-machining method uses the aforementioned complex free-form surface laser jet-assisted conformal micro-machining device. This machining method includes the following steps:

[0015] S1. On the PC side, use a coordinate measuring machine to scan the workpiece to be machined with a complex surface, determine the coordinates of each machining point on the machining path, use the differential method to calculate the tangent slope of the surface at each machining point, and calculate the laser incident angle of the laser at each machining point in a way that the laser is perpendicular to the tangent. And send the data of the laser incident angle to the bus control system;

[0016] The bus control system determines the jet incident angle through simulation;

[0017] The simulation steps include:

[0018] (1) Determination of core variables: including the laser incident angle , the jet incident angle , the pressure of the water jet , the flow rate of the water jet , the power of the laser , material hardness, thermal conductivity, absorptivity, surface curvature radius, and normal vector change rate;

[0019] (2) Construct a simulation model of multiple physical fields. Based on the parameters of the water jet, construct a model for simulating the impact distribution of the water jet based on the Navier-Stoke equation, and simulate the impact force distribution of the water jet and the incident angle of the jet on the slag removal efficiency;

[0020] (3) Construct a laser-material thermal coupling model and a material removal rate empirical model according to the parameters of the laser and the material, analyze the energy absorption during laser incidence, and calculate the cooling effect and thermal stress distribution of the water jet at different angles;

[0021] (4) Select the incident angle of the jet , the water jet pressure , the water jet flow rate , the laser power as variables, set them to 3-5 levels, generate a simulation matrix, and output the surface roughness , the material removal rate , the width of the heat affected zone . According to the simulation model of multiple physical fields and the multiple linear regression method, establish the functional relationship of the incident angle of the jet :

[0022] ;

[0023] Establish a quadratic regression equation for the incident angle of the jet :

[0024] ;

[0025] In the formula are all regression coefficients. Through ANOVA analysis, significant terms are screened and the model is retained;

[0026] Among them, is the coefficient of determination, which is used to measure the fitting degree of the regression model to the observed data. Its value ranges from 0 to 1, and the closer it is to 1, the better the fitting effect of the model to the data;

[0027] Optimize and determine the initial incident angle of the jet through the genetic algorithm. Taking a certain processing point on the free-form surface workpiece as the origin O, establish a local rectangular coordinate system O-xyz; among them, the axis coincides with the surface normal of the workpiece at this processing point, and the direction points to the side away from the workpiece; determine the mutually perpendicular x-axis and y-axis on the workpiece surface to form a right-handed coordinate system;

[0028] The laser incident angle is the angle between the laser beam propagation direction and the positive direction of the axis, and the range is ;

[0029] Jet injection angle is the angle between the central axis of the jet and the positive direction of the axis, and the range is ;

[0030] The angle between the laser and the jet is ;

[0031] Laser incident angle By adjusting the first deformable mirror, the second deformable mirror, and the third deformable mirror to make it perpendicular to the tangent line, that is, it always coincides with the normal vector of the tangent plane in the coordinate system, the laser incident angle is always zero, that is ;

[0032] According to the cosine theorem of spherical triangles, the three angles are related, that is , where is the angle between the projections of the laser and the jet on the x-y plane;

[0033] Because , then ;

[0034] Finally, we can get ;

[0035] Because , , in this range the cosine function is monotonic, so at this time the jet injection angle ;

[0036] When the initial jet injection angle is determined to be a fixed value through simulation, the angle between the laser and the jet is also always a fixed value, that is, the best cooperation with the laser beam has been achieved when the jet injection angle is adjusted for the first time. During the processing, as long as the dynamic coordination between the laser beam and the water jet is maintained, that is, the angle of position change of the laser beam relative to the previous state is equal to the angle of position change of the water jet relative to the previous state;

[0037] S2. Clamp the workpiece to be processed stably on the stage through the workpiece fixture to ensure that there is no displacement deviation during the subsequent processing. Then turn on the laser. After the laser beam passes through the first deformable mirror, the second deformable mirror, and the third deformable mirror, it is focused by the focusing mirror to form a laser optical path and irradiate on the surface of the workpiece;

[0038] S3. After initially adjusting the position of the nozzle to the area irradiated by the laser spot by using the nozzle manual slide and the nozzle two-way manual slide, turn on the jet-assisted conformal nozzle mechanism;

[0039] S4. Meanwhile, turn on the bus control system and precisely control the X-axis slide, Y-axis slide, Z-axis slide, the first deformable mirror, the second deformable mirror, the third deformable mirror, the rotation shaft motor, and the turntable motor through the bus control system. According to the simulation results of Step 1, adjust the laser incident angle to the initial angle, and adjust the incident angle of the water jet to the initial angle as well, and then start processing. The bus control ensures that the position change angle of the laser incident angle relative to the previous processing position is equal to the change angle of the incident angle of the water jet relative to the previous processing position, so that the laser processing unit and the water jet unit are in the best cooperative state.

[0040] Furthermore, the liquid medium ejected by the jet-assisted conformal nozzle mechanism is water, which is placed in a water storage tank, and the jet velocity is adjusted by a high-pressure argon gas tank connected to the water storage tank.

[0041] The beneficial effects of the present invention are as follows:

[0042] 1. Compared with a fixed nozzle that can only promote heat conduction in a specific direction, the jet-assisted conformal nozzle can drive heat to spread in multiple directions, effectively avoiding excessive heat accumulation in a certain local area, thus preventing the occurrence of thermal stress concentration, and then improving the processing quality. This is of great significance for the processing of complex free-form surfaces of heat-sensitive materials such as titanium alloys and aluminum alloys, and can effectively avoid material deformation and performance deterioration caused by thermal effects;

[0043] 2. When facing materials with different shapes, structures, and physical properties, the jet-assisted conformal nozzle can conveniently adjust the incident angle of the water flow to ensure that the processing conditions are adapted to the material characteristics. For complex free-form surfaces, by precisely controlling the water jet, it cooperates with the laser at the best angle and parameters at each processing point. From the perspective of mechanical motion control, the accuracy of the processing process is guaranteed, and errors caused by processing angle deviation are effectively avoided. In terms of processing accuracy, the cutting cone angle is significantly reduced, the seam parallelism is greatly improved, and the dimensional accuracy is precisely guaranteed, fully meeting the strict accuracy requirements for complex curved surface parts in high-end manufacturing fields such as aerospace and high-end mold manufacturing;

[0044] 3. Compared with the current nozzles, the water flow ejected by the jet-assisted conformal nozzle can impact the slag generated after processing from multiple directions, effectively avoiding the situation where the slag accumulates in only one direction. And through adjustment, it can be ensured that the laser irradiation area falls within the overlapping area formed by multiple water jet impacts, so as to achieve the complete removal of the slag and ensure the subsequent process treatment of the workpiece;

[0045] 4. The operation difficulty of this device is small, and the degree of automation of the nozzle is high, which can avoid errors caused by manual adjustment of the nozzle and greatly reduce the use cost. Brief Description of the Drawings

[0046] Figure 1 is a schematic structural diagram of the device of the present invention;

[0047] Figure 2 is Figure 1 an enlarged view of part A in;

[0048] Figure 3 is a schematic structural diagram of the nozzle fixing mechanism of the device of the present invention;

[0049] Figure 4 is a schematic structural diagram of the jet-assisted conformal nozzle mechanism of the device of the present invention;

[0050] Figure 5 is a sectional view of the jet-assisted conformal nozzle mechanism of the device of the present invention;

[0051] Figure 6 is a schematic diagram showing the connection relationship between the spray bar and the nozzle fixture of the device of the present invention;

[0052] Figure 7 is a schematic structural diagram of the nozzle fixture of the device of the present invention;

[0053] Figure 8 is a schematic structural diagram of the motor connecting plate of the device of the present invention;

[0054] Figure 9 is a schematic structural diagram of the motor base of the device of the present invention;

[0055] Figure 10 is a processing principle diagram of the method of the present invention.

[0056] In the figure, 1 - gantry support, 2 - X slide, 3 - X slide adapter plate, 4 - laser, 5 - Z slide adapter plate, 6 - Z slide, 7 - Y slide adapter plate, 8 - Y slide, 9 - marble platform, 10 - breadboard, 11 - first deformable mirror, 12 - second deformable mirror, 13 - third deformable mirror, 14 - focusing mirror, 15 - workpiece fixture, 16 - protective cover, 17 - carrier table, 18 - workpiece to be processed, 19 - nozzle manual slide, 20 - connecting plate, 21 - nozzle two-way manual slide, 22 - manual slide adapter plate, 23 - bearing end cover, 24 - rolling bearing, 25 - bushing, 26 - connection key, 27 - turntable, 28 - carrier, 29 - nozzle fixture, 30 - rotating shaft, 31 - motor base, 32 - rotating shaft coupling, 33 - rotating shaft motor, 34 - turntable motor, 35 - turntable coupling, 36 - motor connecting plate, 37 - nozzle connecting rod, 38 - nozzle. Detailed Description of the Invention

[0057] A complex free-form surface laser jet-assisted conformal micro-machining device, including a marble platform 9, on which a gantry support 1 is fixedly arranged, and on the gantry support 1, an X slide 2 is fixedly arranged. The slider of the X slide 2 is fixedly connected to a breadboard 10 through an X slide adapter plate 3. A laser processing unit and a water jet unit are arranged on the breadboard 10. The X slide 2 can control the positions of the laser processing unit and the water jet unit in the transverse direction;

[0058] On the marble platform 9 below the X slide 2, a Y slide 8 is also fixedly arranged. The slider of the Y slide 8 is fixedly connected to a Z slide 6 through a Y slide adapter plate 7. The slider of the Z slide 6 is fixedly connected to a protective cover 16 through a Z slide adapter plate 5. A carrier table 17 is fixedly arranged inside the protective cover 16, and a workpiece fixture 15 for fixing a workpiece to be machined 18 is fixedly arranged on the carrier table 17. The Z slide 6 and the Y slide 8 can control the position of the workpiece to be machined 18 on the horizontal plane;

[0059] The laser processing unit includes a laser 4, a first deformable mirror 11, a second deformable mirror 12, a third deformable mirror 13, and a focusing mirror 14. The focusing mirror 14 is fixedly connected below the third deformable mirror 13. Light guide tubes are arranged between the laser 4 and the first deformable mirror 11, between the first deformable mirror 11 and the second deformable mirror 12, and between the second deformable mirror 12 and the third deformable mirror 13;

[0060] The first deformable mirror 11, the second deformable mirror 12, and the third deformable mirror 13 themselves have driving mechanisms and can adjust the angle between the incident laser and the mirror surface;

[0061] The water jet unit includes a nozzle fixing mechanism and a jet-assisted conformal nozzle mechanism. The nozzle fixing mechanism includes a nozzle manual slide 19 and a nozzle two-way manual slide 21. One end of the nozzle manual slide 19 is bolted to the breadboard 10, and the other end is fixedly connected to the top of the nozzle two-way manual slide 21 through a connecting plate 20. The bottom of the nozzle two-way manual slide 21 is bolted to the jet-assisted conformal nozzle mechanism through a manual slide adapter plate 22. The positions of the jet-assisted conformal nozzle mechanism can be adjusted in three mutually perpendicular directions through the nozzle manual slide 19 and the nozzle two-way manual slide 21;

[0062] It further includes a bus control system, which is communicatively connected to the first deformable mirror 11, the second deformable mirror 12, the third deformable mirror 13, the X stage 2, the Y stage 8, the Z stage 6, and the jet-assisted conformal nozzle mechanism. The bus control system can adjust the angles of the first deformable mirror 11, the second deformable mirror 12, and the third deformable mirror 13, and can also adjust the displacements of the X stage 2, the Y stage 8, and the Z stage 6;

[0063] Further, the jet-assisted conformal nozzle mechanism includes a bearing end cover 23, a rolling bearing 24, a bushing 25, a connection key 26, a turntable 27, a carrier 28, a nozzle fixture 29, a rotating shaft 30, a motor base 31, a rotating shaft coupling 32, a rotating shaft motor 33, a turntable motor 34, a turntable coupling 35, a motor connecting plate 36, a nozzle connecting rod 37, and a nozzle 38. The motor shaft of the turntable motor 34 is connected to the turntable drive shaft through the turntable coupling 35. The turntable motor 34 is fixed on the motor connecting plate 36. The turntable 27 and the motor connecting plate 36 are connected to the manual stage adapter plate 22 through mounting holes and bolts. The carrier 28 is fixedly connected to the output rotating shaft of the turntable 27. The bearing end cover 23 is connected to the carrier 28 by threads and is used to limit the movement of the rolling bearing 24. The rolling bearing 24 is used to reduce the friction and wear of the rotating shaft 30. The nozzle fixture 29 is connected to the rotating shaft 30 through the connection key 26 and can rotate with the rotating shaft 30. The bushing 25 and the shoulder of the rotating shaft 30 jointly limit the nozzle fixture 29. The nozzle 38 and the nozzle connecting rod 37 are connected together by nuts. The nozzle connecting rod 37 is fixed on the nozzle fixture 29. The motor base 31 is connected to the carrier 28 by bolts. The rotating shaft motor 33 is connected to the motor base 31 through a long screw. The motor shaft of the rotating shaft motor 33 is connected to the rotating shaft 30 through the rotating shaft coupling 32. Both the rotating shaft motor 33 and the turntable motor 34 are communicatively connected to the bus control system.

[0064] A complex free-form surface laser jet-assisted conformal micro-machining method uses the aforementioned complex free-form surface laser jet-assisted conformal micro-machining device. The machining method includes the following steps:

[0065] S1. Scan the workpiece 18 with a complex surface on the PC side through a coordinate measuring machine to determine the coordinates of each machining point on the machining path. For each machining point, use the difference method to calculate the tangent slope of the surface at this machining point, and calculate the laser incident angle of the laser at each machining point in a way that the laser is perpendicular to the tangent. and send the data of the laser incident angle

[0066] to the bus control system; The bus control system determines the jet incident angle​

[0067] The simulation steps include:

[0068] (1) Determination of core variables: including the laser incident angle , the injection incident angle , the pressure of the water jet , the flow rate of the water jet , the power of the laser , material hardness, thermal conductivity, absorptivity, surface curvature radius, and normal vector change rate;

[0069] (2) Construct a simulation model of multiple physical fields. Based on the parameters of the water jet, construct a model to simulate the impact distribution of the water jet based on the Navier-Stoke equation, and simulate the impact force distribution of the water jet and the influence of the injection incident angle on the slag removal efficiency;

[0070] (3) Construct a laser-material thermal-mechanical coupling model and a material removal rate empirical model according to the parameters of the laser and the material, analyze the energy absorption during laser incidence, and calculate the cooling effect and thermal stress distribution of the water jet at different angles;

[0071] (4) Select the injection incident angle , the water jet pressure , the water jet flow rate , and the laser power as variables, set them to 3-5 levels, generate a simulation matrix, and output the surface roughness , material removal rate , heat affected zone width . According to the simulation model of multiple physical fields and the multiple linear regression method, establish the functional relationship of the injection incident angle :

[0072] ;

[0073] Establish the quadratic regression equation of the injection incident angle :

[0074] ;

[0075] In the formula are all regression coefficients. Screen the significant terms through ANOVA analysis and retain the model;

[0076] Among them, is the coefficient of determination, which is used to measure the fitting degree of the regression model to the observed data. Its value ranges from 0 to 1, and the closer it is to 1, the better the fitting effect of the model to the data;

[0077] Optimize and determine the initial jet injection angle through genetic algorithm Taking a machining point on the free-form surface workpiece as the origin O, establish a local rectangular coordinate system O-xyz; where the z-axis coincides with the surface normal of the workpiece at this machining point, and the direction points to the side away from the workpiece; determine the mutually perpendicular x-axis and y-axis on the workpiece surface to form a right-handed coordinate system;

[0078] Laser incident angle is the angle between the laser beam propagation direction and the positive direction of the z-axis, and the range is ;

[0079] Jet injection angle is the angle between the jet central axis and the positive direction of the z-axis, and the range is ;

[0080] The angle between the laser and the jet is ;

[0081] Laser incident angle By adjusting the first deformable mirror 11, the second deformable mirror 12, and the third deformable mirror 13 to make it perpendicular to the tangent line, that is, always coincide with the normal vector of the tangent plane in the coordinate system, then the laser incident angle is always zero, that is ;

[0082] Connect the three angles according to the cosine theorem of spherical triangle, that is , where is the angle between the projections of the laser and the jet on the x-y plane;

[0083] Because , then ;

[0084] Finally, we can get ;

[0085] Because , , in this range the cosine function is monotonic, so at this time the jet injection angle ;

[0086] When the initial jet injection angle is determined to be a fixed value through simulation, the angle between the laser and the jet is also always a fixed value, that is, the best cooperation with the laser beam has been achieved when adjusting the jet injection angle for the first time. During the machining process, as long as the dynamic coordination between the laser beam and the water jet is maintained, that is, the angle of the laser beam relative to the previous state's position change is equal to the angle of the water jet relative to the previous state's position change;

[0087] S2. Steadily clamp the workpiece 18 to be processed on the stage 17 through the workpiece fixture 15 to ensure that there is no displacement deviation during the subsequent processing. Then, turn on the laser 4. After the laser beam passes through the first deformable mirror 11, the second deformable mirror 12, and the third deformable mirror 13, it is focused by the focusing mirror 14 to form a laser optical path and irradiate on the surface of the workpiece.

[0088] S3. After initially adjusting the position of the nozzle to the area irradiated by the laser spot using the nozzle manual slide 19 and the nozzle two-way manual slide 21, turn on the jet-assisted conformal nozzle mechanism.

[0089] S4. At the same time, turn on the bus control system, and precisely control the X slide 2, Y slide 8, Z slide 6, the first deformable mirror 11, the second deformable mirror 12, the third deformable mirror 13, the rotating shaft motor 33, and the turntable motor 34 through the bus control system. According to the simulation results of step one, adjust the laser incident angle to the initial angle, adjust the jet incident angle to the initial angle as well, and start the processing. The bus control ensures that the position change angle of the laser incident angle relative to the previous processing position is equal to the change angle of the jet incident angle relative to the previous processing position, so that the laser processing unit and the water jet unit are in the best cooperative state.

[0090] During the process of the nozzle 38 being adjusted with the change of the laser incident angle, the left and right swing of the nozzle 38 will increase the width of the jet area, and the up and down swing of the nozzle 38 will increase the length of the jet area after the swing, thus forming a larger water jet area. During this process, the position of the laser spot is always in the overlapping area of each water jet spray. These water flows generate multi-directional impact forces in the processing area, and its main purpose is to completely remove the slag generated during the processing from the surface of the workpiece to ensure that the processing area is always kept clean, and finally achieve high-quality processing results output. Finally, the waste liquid during the processing will be discharged through the drain pipe into the container for storing the waste liquid.

[0091] Further, the liquid medium sprayed by the jet-assisted conformal nozzle mechanism is water, which is placed in the water storage tank, and the jet velocity is adjusted by the high-pressure argon gas tank connected to the water storage tank.

[0092] The above is only the preferred specific implementation manner of the present invention, and it is not a limitation to the present invention. Any equivalent replacement and modification made by any person skilled in the art without departing from the guidance of the present invention shall be regarded as falling within the protection scope of the present invention.

Claims

1. A complex free-form surface laser jet-assisted conformal micro-machining method, which uses a complex free-form surface laser jet-assisted conformal micro-machining device, is characterized in that The complex free-form surface laser jet-assisted conformal micro-machining device includes a marble platform (9). A gantry bracket (1) is fixedly arranged on the marble platform (9). An X slide table (2) is fixedly arranged on the gantry bracket (1). The slider of the X slide table (2) is fixedly connected to a breadboard (10) through an X slide table adapter plate (3). A laser processing unit and a water jet unit are arranged on the breadboard (10). A Y slide table (8) is also fixedly arranged on the marble platform (9) below the X slide table (2). The slider of the Y slide table (8) is fixedly connected to a Z slide table (6) through a Y slide table adapter plate (7). The slider of the Z slide table (6) is fixedly connected to a protective cover (16) through a Z slide table adapter plate (5). A carrier table (17) is fixedly arranged inside the protective cover (16). A workpiece fixture (15) for fixing a workpiece to be machined (18) is fixedly arranged on the carrier table (17). The laser processing unit includes a laser (4), a first deformable mirror (11), a second deformable mirror (12), a third deformable mirror (13), and a focusing mirror (14). The focusing mirror (14) is fixedly connected below the third deformable mirror (13). Light guide tubes are arranged between the laser (4) and the first deformable mirror (11), between the first deformable mirror (11) and the second deformable mirror (12), and between the second deformable mirror (12) and the third deformable mirror (13). The water jet unit includes a nozzle fixing mechanism and a jet-assisted conformal nozzle mechanism. The nozzle fixing mechanism includes a nozzle manual slide table (19) and a nozzle two-way manual slide table (21). One end of the nozzle manual slide table (19) is bolted to the breadboard (10), and the other end is fixedly connected to the top of the nozzle two-way manual slide table (21) through a connecting plate (20). The bottom of the nozzle two-way manual slide table (21) is bolted to the jet-assisted conformal nozzle mechanism through a manual slide table adapter plate (22). The position of the jet-assisted conformal nozzle mechanism can be adjusted in three mutually perpendicular directions through the nozzle manual slide table (19) and the nozzle two-way manual slide table (21). It also includes a bus control system. The bus control system is communicatively connected to the first deformable mirror (11), the second deformable mirror (12), the third deformable mirror (13), the X slide table (2), the Y slide table (8), the Z slide table (6), and the jet-assisted conformal nozzle mechanism. The jet-assisted conformal nozzle mechanism includes a bearing end cover (23), a rolling bearing (24), a bushing (25), a connection key (26), a turntable (27), a carrier (28), a nozzle fixture (29), a rotating shaft (30), a motor base (31), a rotating shaft coupling (32), a rotating shaft motor (33), a turntable motor (34), a turntable coupling (35), a motor connecting plate (36), a nozzle connecting rod (37), and a nozzle (38). The motor shaft of the turntable motor (34) is connected to the turntable drive shaft through the turntable coupling (35). The turntable motor (34) is fixed on the motor connecting plate (36). The turntable (27) and the motor connecting plate (36) are connected to the manual slide table adapter plate (22) through mounting holes and bolts. The carrier (28) is fixedly connected to the output rotating shaft of the turntable (27). The bearing end cover (23) is connected to the carrier (28) by threads and is used to limit the movement of the rolling bearing (24). The rolling bearing (24) is used to reduce the friction and wear of the rotating shaft (30). The nozzle fixture (29) is connected to the rotating shaft (30) through the connection key (26) and can rotate with the rotating shaft (30). The bushing (25) and the shaft shoulder of the rotating shaft (30) jointly limit the nozzle fixture (29). The nozzle (38) and the nozzle connecting rod (37) are connected together by nuts. The nozzle connecting rod (37) is fixed on the nozzle fixture (29). The motor base (31) is connected to the carrier (28) by bolts. The rotating shaft motor (33) is connected to the motor base (31) through a long screw. The motor shaft of the rotating shaft motor (33) is connected to the rotating shaft (30) through the rotating shaft coupling (32). Both the rotating shaft motor (33) and the turntable motor (34) are communicatively connected to the bus control system; The complex free-form surface laser jet-assisted conformal micro-machining method includes the following steps: S1. On the PC side, use a coordinate measuring machine to scan the workpiece (18) with a complex surface to be machined, determine the coordinates of each machining point on the machining path, calculate the tangent slope of the surface at each machining point using the difference method for each machining point, and calculate the laser incident angle of the laser at each machining point by the way that the laser is perpendicular to the tangent , and send the data of the laser incident angle to the bus control system; The bus control system determines the incident angle of the jet through simulation for determination; The simulation step includes: (1) Determination of core variables: including laser incident angle , jet incidence angle , the pressure of the water jet , the flow rate of the water jet , the power of the laser , material hardness, thermal conductivity, absorptivity, surface curvature radius, and normal vector change rate; (2) Build a simulation model of multi-physical fields. Based on the parameters of the water jet, construct a model to simulate the impact distribution of the water jet based on the Navier-Stoke equation, and simulate the distribution of the water jet impact force and the incident angle of the water jet Influence on the slag removal efficiency; (3)Construct a laser-material thermo-mechanical coupling model and a material removal rate empirical model based on the parameters of the laser and the material, analyze the energy absorption during laser incidence, and calculate the cooling effect and thermal stress distribution of the water jet at different angles; (4) Select the jet incident angle , water jet pressure , water jet velocity , laser power is a variable, set to 3~5 levels, generate a simulation matrix, and output the surface roughness , material removal rate , Heat affected zone width , based on the multi-physics simulation model and multiple linear regression method, the jet incident angle is established Functional relationship: ； Establish the quadratic regression equation of the jet injection angle : ； where are all regression coefficients. Significant terms are selected through ANOVA analysis, and the model with is retained. in, It is the coefficient of determination, which is used to measure the degree of fit of the regression model to the observed data. Its value ranges from 0 to 1. The closer it is to 1, the better the model fits the data. Optimizing and determining the initial jet injection angle through a genetic algorithm , taking a machining point on the free-form surface workpiece as the origin O, a local rectangular coordinate system O-xyz is established; among them, the z-axis coincides with the surface normal of the workpiece at this machining point, and the direction points to the side away from the workpiece; on the workpiece surface, mutually perpendicular x-axis and y-axis are determined to form a right-handed coordinate system; Laser incident angle is the angle between the laser beam propagation direction and the positive direction of the z-axis, and the range is ; Jet incident angle is the angle between the jet center axis and the positive direction of the z axis, and the range is ; The angle between the laser and the jet is ; Laser incident angle By regulating the first deformable reflector (11), the second deformable reflector (12), and the third deformable reflector (13) so that they are perpendicular to the tangent line, that is, they always coincide with the normal vector of the tangent plane in the coordinate system, the laser incident angle is always zero, that is, ; Relate the three angles according to the cosine theorem of spherical triangles, that is , where is the angle between the laser and the projection of the jet in the x-y plane; because ,but ; Finally you can get ; Because , , in this range the cosine function is monotonic, so at this time the injection angle of the jet ; When the initial jet incident angle After being determined as a constant value through simulation, the angle between the laser and the jet It is always a constant value, that is, when the jet incident angle is adjusted for the first time The best cooperation with the laser beam has been achieved. During the processing, it is only necessary to maintain the dynamic coordination between the laser beam and the water jet, that is, the angle of change of the position of the laser beam relative to the previous state is equal to the angle of change of the position of the water jet relative to the previous state. S2. The workpiece to be machined (18) is stably clamped on the stage (17) by the workpiece fixture (15) to ensure that there is no displacement deviation during the subsequent machining process. Then, the laser (4) is turned on. After the laser beam passes through the first deformable mirror (11), the second deformable mirror (12), and the third deformable mirror (13), it is focused by the focusing mirror (14) to form a laser light path and irradiate on the workpiece surface; S3. After the position of the nozzle is initially adjusted to the area irradiated by the laser spot by using the nozzle manual slide (19) and the nozzle two-way manual slide (21), the jet-assisted conformal nozzle mechanism is turned on; S4. Simultaneously open the bus control system and precisely control the X slide (2), Y slide (8), Z slide (6), first deformable reflector (11), second deformable reflector (12), third deformable reflector (13), shaft motor (33) and turntable motor (34) through the bus control system. According to the simulation results of step 1, the laser incident angle is adjusted. Adjust to the initial angle and change the jet incident angle Also adjust to the initial angle and start processing, bus control to ensure the laser incident angle The angle of position change relative to the last processing position is equal to the jet incidence angle The changed angle relative to the previous processing position puts the laser processing unit and the water jet unit in the best coordinated state.

2. The method for laser jet-assisted conformal micromachining of complex free-form surfaces according to claim 1, characterized in that: The liquid medium ejected by the jet-assisted conformal nozzle mechanism is water. The water is placed in a water storage tank, and the jet velocity is adjusted by a high-pressure argon gas tank connected to the water storage tank.

Images