Abrasive particle jet flow polishing method based on simulation path optimization and sound wave control

Abstract

The invention discloses an abrasive particle jet flow polishing method based on simulation path optimization and sound wave control, and relates to the technical field of precision machining, the abrasive particle jet flow polishing method comprises the following steps: S1, placing a workpiece and preparing an abrasive particle-containing liquid medium; s2, machining parameters are set, and a scanning path is planned; and S3, a polishing process. According to the method, the workpiece three-dimensional model is subjected to surface discretization processing and divided into a plurality of point cloud grid areas, then the surface complexity of the workpiece three-dimensional model is calculated, the simulation point positions are dynamically distributed, the optimal focus separation amount curved surface is obtained through calculation based on the multiphase flow method according to the simulation point positions, and then the optimized laser scanning path is obtained according to the optimal focus separation amount curved surface. And then uniform suspension and precise control of the abrasive particles are achieved in combination with a phase-controlled sound wave array, the influence of the laser-induced cavitation polishing technology on the shape of the wall face of the workpiece on the cavitation pulsation process is fully considered, and the polishing quality and efficiency are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of precision machining, and in particular to an abrasive jet polishing method based on simulation path optimization and acoustic wave control. Background Art

[0002] Laser-induced cavitation polishing technology is a non-contact polishing method suitable for processing various high-hardness and complex-shaped workpieces. However, the existing laser-induced cavitation technology has problems such as low polishing efficiency, uneven surface quality, and difficulty in accurately controlling polishing parameters in practical applications. In addition, mechanical stirring still causes uneven distribution of abrasive particles in the liquid medium, thus affecting the processing accuracy and surface quality. One of the important reasons is that the existing laser-induced cavitation polishing technology does not consider the influence of the wall shape on the cavitation pulsation process.

[0003] During the pulsation process, cavitation will be affected by the surrounding fluid and solid boundaries (such as the outer surface of the workpiece). If the surface of the workpiece is complex and uneven, it will cause uneven pressure distribution when the cavitation collapses, thereby affecting the direction and intensity of the microjet. Such unevenness will affect the polishing effect.

[0004] The background description provided herein is for the purpose of generally presenting the context of the present disclosure. Unless otherwise indicated herein, the materials described in this section are not prior art to the claims of this application and are not admitted to be prior art by inclusion in this section. Summary of the invention

[0005] In view of the above technical problems in the related art, the present invention proposes an abrasive jet polishing method based on simulation path optimization and acoustic wave control.

[0006] In the first aspect, the present invention provides an abrasive jet polishing device based on simulation path optimization and acoustic wave control, the device comprising: a three-dimensional motion platform, a laser located on the three-dimensional motion platform, a high-energy pulse laser generated by the laser, a water tank located below the laser, a fixture located at the bottom of the water tank for clamping a workpiece, a phased array acoustic wave array located on both sides of the water tank, a phased array control system for controlling the phased array acoustic wave array, and an optical detection system for monitoring the position of abrasive particles; a computer control system connected to the laser and the three-dimensional motion platform, used for numerical simulation calculations, laser scanning path planning and processing parameter adjustment, and controlling the three-dimensional motion platform to drive the laser to move; the computer control system is also connected to the phased array control system and the optical detection system, and is used to monitor the position of abrasive particles in real time and control acoustic wave parameters.

[0007] In a second aspect, the present invention provides an abrasive jet polishing method based on simulation path optimization and acoustic wave control, based on the abrasive jet polishing device based on simulation path optimization and acoustic wave control in the first aspect, comprising the following steps:

[0008] S1, placing a workpiece and preparing a liquid medium containing abrasive particles: firstly placing the workpiece in the water tank and fixing the workpiece with a fixture, then adding pure water to the water tank, and finally adding abrasive particles to the water tank;

[0009] S2, setting processing parameters and planning scanning path: setting relevant parameters of the laser through the computer control system; obtaining the surface point cloud data of the workpiece through the computer control system to calculate its surface complexity, and then dynamically allocating the workpiece simulation points according to the surface complexity, and finally obtaining the optimized laser scanning path based on the simulation points based on the multiphase flow method;

[0010] S3, polishing process: start the phased array control system, phased acoustic wave array and optical detection system, and after the abrasive particles are evenly suspended, start the laser and polish the workpiece according to the optimized laser scanning path.

[0011] Specifically, step S2 specifically includes:

[0012] S21, discretizing the three-dimensional model of the workpiece to obtain point cloud data of the workpiece surface;

[0013] S22, dividing the workpiece surface point cloud data into a plurality of point cloud grid areas according to the range of the workpiece surface point cloud data on the X axis and the Y axis;

[0014] S23, calculating the surface complexity of each point cloud grid region by the distance from the discrete points in the point cloud grid region to the reference surface; the surface complexity is the set of complexities of the discrete points in the point cloud grid region;

[0015] S24, adjusting the number of simulation points in each point cloud grid area according to the surface complexity of each point cloud grid area, and then exporting the position coordinate data of the adjusted simulation points as a simulation point data file; the adjustment is specifically: the simulation points allocated in the point cloud grid area are proportional to its surface complexity;

[0016] S25, after setting the simulation conditions, import the simulation point data file, and then perform numerical simulation based on the multiphase flow method and fit to obtain the optimal focus distance surface;

[0017] S26, performing path planning according to the optimal focus distance surface to obtain an optimized laser scanning path;

[0018] Specifically, step S21 specifically includes:

[0019] S211, using the stlread function in MATLAB to read the workpiece 3D model file from the specified path and extract the vertex data of the model;

[0020] S212, using the vertices function to discretize the vertex data according to a preset number of controlled discrete points to obtain workpiece surface point cloud data.

[0021] Specifically, step S22 specifically includes:

[0022] S221, obtaining the maximum value and minimum value of the workpiece surface point cloud data in the X direction, the maximum value and minimum value in the Y direction;

[0023] S222, dividing the workpiece surface point cloud data into two-dimensional point cloud grid areas by using the linspace function according to the maximum value in the X direction, the minimum value in the X direction, the maximum value in the Y direction, and the minimum value in the Y direction.

[0024] Specifically, step S23 specifically includes:

[0025] S231, selecting a plane in the Z-axis direction as a reference plane;

[0026] S232. Traverse all point cloud grid areas. If the number of discrete points in the point cloud grid area is greater than 0, calculate the distance from each discrete point in the point cloud grid area to the reference plane, and calculate the standard deviation of the distance as the complexity of the discrete point, and then obtain the surface complexity of the point cloud grid area; if the number of discrete points in the point cloud grid area is 0, the surface complexity of the point cloud grid area is 0.

[0027] Specifically, the step S24 described in which the number of simulation points in each point cloud grid area is adjusted according to the surface complexity of each point cloud grid area is as follows: traverse the discrete points of each point cloud grid area, and if the complexity of the point is greater than 0, use the round(a*discrete point complexity) function to obtain the number of simulation points corresponding to the point; if the complexity of the discrete point is less than or equal to 0, set the simulation point corresponding to the point to 0; wherein a is the adjustment factor.

[0028] Specifically, step S25 specifically includes:

[0029] S251. Prepare the Fluent simulation environment: Use Ansys Workbench to import the 3D model of the workpiece into the Fluent pre-processor, create the fluid domain and set the boundary conditions, and set the required physical model, material properties, boundary conditions, initial conditions, etc. in Fluent.

[0030] S252. Import simulation points and automatically perform simulation: After the boundary conditions are set, use Fluent to load the simulation point data file, read the location information of the simulation point, and automatically perform numerical simulation based on the multiphase flow method at each simulation point to obtain the optimal defocus value corresponding to each point:

[0031] S253, exporting simulation results and fitting to obtain an optimal defocus surface: after the simulation is completed, the optimal defocus data is exported and then read through MATLAB, and the optimal defocus of each simulation point is fitted through the griddata function to obtain an optimal defocus surface;

[0032] Specifically, step S26 specifically includes: when planning the path, a zigzag strategy is adopted in the X and Y directions, the Z direction is adjusted according to the optimal defocus surface, and interpolation is performed in the Z direction through the interp2 function, and finally an optimized laser scanning path is obtained.

[0033] Specifically, the phased acoustic wave array is composed of a plurality of acoustic wave emitting units, each of which can be controlled individually; the phased array control system is connected to the phased acoustic wave array and is used to adjust the frequency, amplitude and phase of the acoustic waves generated by the acoustic wave emitting units to achieve precise suspension control of the abrasive particles.

[0034] Specifically, the computer control system uses a PID control algorithm to optimize the position of abrasive particle suspension.

[0035] The present invention discretizes the surface of the three-dimensional model of the workpiece and divides it into multiple point cloud grid areas, then calculates its surface complexity and dynamically allocates simulation points, and calculates the optimal focus surface based on the simulation points based on the multiphase flow method, and then obtains the optimized laser scanning path based on the optimal focus surface, and then combines the phased acoustic wave array to achieve uniform suspension and precise control of the abrasive particles, fully considering the influence of the laser-induced cavitation polishing technology on the workpiece wall shape on the cavitation pulsation process, and significantly improving the polishing quality and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A schematic diagram of the structure of abrasive jet polishing based on simulation path optimization and acoustic wave control provided by an embodiment of the present invention;

[0038] Figure 2A schematic diagram of the structure of a clamp provided in an embodiment of the present invention;

[0039] Figure 3 A schematic diagram of the polishing principle of the polishing method provided by an embodiment of the present invention;

[0040] Figure 4 A schematic diagram of an abrasive jet polishing method based on simulation path optimization and acoustic wave control provided by an embodiment of the present invention;

[0041] Figure 5 A schematic diagram of the effect of discretizing the surface of a three-dimensional model into point cloud data provided by an embodiment of the present invention;

[0042] Figure 6 A schematic diagram of the effect of dividing point cloud data into multiple areas provided by an embodiment of the present invention;

[0043] Figure 7 A schematic diagram of the calculation results of the complexity of each region provided by an embodiment of the present invention;

[0044] Figure 8 A schematic diagram of the result of allocating simulation points according to the complexity of each area provided in an embodiment of the present invention;

[0045] Fig. 9 A schematic diagram of a zigzag path provided by an embodiment of the present invention;

[0046] Fig.10 A straight line schematic diagram provided for an embodiment of the present invention;

[0047] Fig.11 A schematic diagram of the structure of the phased acoustic wave array provided in an embodiment of the present invention;

[0048] Fig.12 A schematic diagram of the principle of acoustic levitation provided by an embodiment of the present invention;

[0049] Fig.13 A schematic diagram of a phased acoustic wave array control process provided by an embodiment of the present invention;

[0050] Among them, 1-three-dimensional motion platform; 2-laser; 3-laser; 4-water tank; 5-phased array wave array, 5-1 is the sound wave emitting unit; 6-cavitation; 7-abrasive; 8-workpiece; 9-fixture; 10-phased array wave array; 11-phased array control system; 12-computer control system; 13-optical detection system. DETAILED DESCRIPTION

[0051] The present invention can be explained in detail through the following embodiments. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention. In the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "front", "back", "left", "right", etc. indicating directions or positional relationships, they only correspond to the drawings of the present application for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific direction.

[0052] Embodiment 1

[0053] refer to Figure 1 This embodiment provides an abrasive jet polishing device based on simulation path optimization and acoustic wave control, comprising: a three-dimensional motion platform 1, a laser 2 located on the three-dimensional motion platform 1, a high-energy pulse laser 3 generated by the laser 2, a water tank 4 located below the laser 2, a phased acoustic wave array 5 located on one side of the water tank 4, cavitation 6 induced by the high-energy pulse laser, suspended abrasive particles 7 located in a liquid medium, a workpiece 8 located at the bottom of the water tank 4, a phased acoustic wave array 10 located on the other side of the water tank 4, and an optical detection system 13 for monitoring the position of abrasive particles;

[0054] A phased array control system 11 for controlling the phased acoustic wave arrays 5 and 9, and a computer control system 12 for controlling the three-dimensional motion platform 1 and the laser 2;

[0055] The clamp 9 is fixed to the bottom of the water tank. Since the workpiece is subjected to relatively little force during processing, the clamp 9 is fixed to the bottom of the water tank by gluing.

[0056] The fixture 9 can clamp and fix the workpiece 8 during the processing to prevent the workpiece 8 from being displaced due to force, which leads to a decrease in processing accuracy. Figure 2 shown.

[0057] Specifically, the phased acoustic array 5 and the phased acoustic array 10 are each composed of a plurality of acoustic wave transmitters, each of which can be controlled individually. The phased array control system 11 is connected to the phased acoustic arrays 5 and 9 to adjust the frequency, amplitude and phase of the acoustic waves generated by the acoustic wave transmitting units to achieve precise suspension control of the abrasive particles.

[0058] Specifically, the computer control system 12 is connected to the three-dimensional motion platform 1, the laser 2, the phased array control system 11 and the optical detection system 13 to control the movement of the three-dimensional motion platform 1, the parameters of the high-energy pulse laser 3 generated by the laser 2, the processing of the images taken by the optical detection system 13, and the real-time parameter adjustment of the phased array control system 11.

[0059] The working principle of the abrasive jet polishing device is: the pulsed laser generated by the laser 2 is irradiated into the water tank 4 containing the abrasive liquid medium, and a high-temperature plasma is generated at the laser focus, which triggers the optical breakdown of the liquid and instantly vaporizes to form cavitation. The cavitation releases a strong shock wave and high-speed micro jets in the collapse stage. Figure 3 As shown, these shock waves and microjets propel the abrasive particles to impact the workpiece surface at high speed, thereby achieving efficient material removal and surface polishing.

[0060] Embodiment 2

[0061] refer to Figure 1 , Figure 4 This embodiment provides an abrasive jet polishing method based on simulation path optimization and acoustic wave control based on the abrasive jet polishing device based on simulation path optimization and acoustic wave control described in embodiment 1, comprising the following steps:

[0062] S1, placing a workpiece and preparing a liquid medium containing abrasive particles: firstly placing the workpiece in the water tank and fixing the workpiece with a fixture, then adding pure water to the water tank, and finally adding abrasive particles to the water tank;

[0063] Specifically, after the workpiece is clamped and fixed by a fixture, pure water is added to the water tank until the workpiece is completely submerged, and the liquid level is preferably 10 mm from the top of the workpiece. Finally, abrasive particles are added to the water tank, and the abrasive particles preferably have a particle size of 90 mesh and a concentration of 1 g / L.

[0064] S2, setting processing parameters and planning scanning path: setting relevant parameters of the laser through the computer control system; obtaining the surface point cloud data of the workpiece through the computer control system to calculate its surface complexity, and then dynamically allocating the workpiece simulation points according to the surface complexity, and finally obtaining the optimized laser scanning path based on the simulation points based on the multiphase flow method;

[0065] The processing parameters refer to the relevant parameters of the laser, including laser energy and trigger frequency.

[0066] The computer control system is used to set the relevant parameters of the laser, including the laser energy and the trigger frequency, and the three-dimensional model of the workpiece is obtained through the computer control system. The surface is discretized and divided into a plurality of point cloud grid areas, and then the surface complexity is calculated to dynamically allocate simulation points, and the optimal focus distance surface is calculated based on the simulation points based on the multiphase flow method, and then the optimized laser scanning path is obtained according to the optimal focus distance surface;

[0067] The specific steps are as follows:

[0068] S21, discretizing the three-dimensional model of the workpiece to obtain point cloud data of the workpiece surface;

[0069] Read the 3D model and discretize the surface: Through the computer control system, the 3D model of the workpiece is first read, the information of each face and vertex in the model is extracted, and the surface of the model is discretized.

[0070] First, through the computer control system, use the stlread function of MATLAB to import the workpiece 3D model file. The workpiece 3D model is usually stored in STL format. Extract the vertex and surface data of the model. On this basis, select a reasonable preset control discrete point number to discretize the model surface. The discretization effect is as follows Figure 5 As shown; the discretized workpiece surface point cloud data represents the workpiece surface and will be used for subsequent simulation.

[0071] Specifically, this embodiment provides a possible specific implementation method, as follows:

[0072] S211, using the stlread function in MATLAB to read the workpiece 3D model file from the specified path, and extract the vertex data and surface data of the model;

[0073] The vertex data includes coordinate information (x, y, z) of the vertex;

[0074] After reading the 3D model file of the workpiece through the stlread function, the vertex data and face data are extracted to obtain the coordinate information (x, y, z) of the vertices on the model surface. These vertex data are the basic geometric data of the 3D model. This step ensures that the original geometric shape of the model can completely retain the vertex coordinates after reading, which is convenient for subsequent discretization processing.

[0075] S212, using the vertices function to discretize the vertex data according to a preset number of controlled discrete points to obtain discretized point cloud data, thereby obtaining workpiece surface point cloud data;

[0076] The point cloud data includes the coordinate information (x, y, z) of the points;

[0077] Specifically, the vertices function is used to process the point cloud data of the 3D model. Its core function is to discretize the surface of the 3D model according to the input control parameters to generate point cloud data suitable for numerical simulation. These discretized point cloud data contain the coordinate information (x, y, z) of each point, providing an accurate surface reference for subsequent simulations based on multiphase flow methods. Through the discretization processing of the vertices function, the point cloud density can be flexibly controlled, so that the simulation can obtain higher accuracy in the area of ​​interest.

[0078] The number of preset control discrete points can be adjusted according to the complexity of the workpiece surface shape. In this embodiment, the number of preset control discrete points is 10,000;

[0079] S22, dividing the workpiece surface point cloud data into a plurality of point cloud grid areas according to the range of the workpiece surface point cloud data on the X axis and the Y axis;

[0080] After the discretized point cloud data is generated, the model surface is divided into multiple point cloud mesh areas according to the range of the discretized point cloud data X-axis and Y-axis. The complexity of each small area of ​​the discrete point data (point cloud mesh area) will be analyzed separately.

[0081] It is understandable that the divided point cloud grid area may contain a large number of discrete point cloud data or may not contain discrete point cloud data;

[0082] S221, obtaining the maximum value and minimum value of the workpiece surface point cloud data in the X direction, the maximum value and minimum value in the Y direction;

[0083] It is understandable that how to obtain the maximum and minimum values ​​of the workpiece surface point cloud data in the X direction and the Y direction is a prior art and will not be described in detail here.

[0084] S222, dividing the workpiece surface point cloud data into two-dimensional point cloud grid areas by using the linspace function according to the maximum value in the X direction, the minimum value in the X direction, the maximum value in the Y direction, and the minimum value in the Y direction;

[0085] The linspace function is used to generate the grid divisions in the X and Y directions. The number of grid divisions is adjustable, which is used to flexibly control the number of division areas. The plan view of the division result is as follows: Figure 6 shown.

[0086] S23, calculating the surface complexity of each point cloud grid region by the distance from the discrete points in the point cloud grid region to the reference surface; the surface complexity is the set of complexities of the discrete points in the point cloud grid region;

[0087] The distance between each discrete point in the point cloud mesh area and the reference surface is used to calculate the standard deviation to measure the surface complexity. The more undulating the surface, the greater the complexity and the higher the standard deviation.

[0088] S231, selecting a plane in the Z-axis direction as a reference plane;

[0089] First, a reference plane Z=0 is selected, that is, the distance between the Z-axis values ​​of all points and this plane will be used as the calculation basis: the value of Z can be adjusted according to specific needs. Preferably, this embodiment selects the plane where Z=0 is located as the reference plane;

[0090] S232, traversing all point cloud grid areas, if the number of discrete points in the point cloud grid area is greater than 0, calculating the distance from each discrete point in the point cloud grid area to the reference plane, and calculating the standard deviation of the distance as the complexity of the discrete point, and then obtaining the surface complexity of the point cloud grid area; if the number of discrete points in the point cloud grid area is 0, the surface complexity of the point cloud grid area is 0;

[0091] The main function of this step is to quantify the complexity of the area by calculating the standard deviation of the distance from discrete points to the reference plane in each point cloud mesh area. The larger the standard deviation, the greater the surface undulation.

[0092] In this embodiment, the standard deviation is a measure of the degree of discreteness of the distance from each discrete point in the point cloud to the reference plane, which can reflect the complexity or unevenness of the surface of the area. When the distances from each discrete point in a point cloud grid area to the reference plane differ greatly, the distribution of these points in space will be more dispersed, indicating that the surface is more undulating; and the standard deviation calculates the degree of discreteness of these distances, so the larger the standard deviation, the greater the difference between these points and the reference plane, and the more obvious the surface undulations. On the contrary, if the standard deviation is small, it means that the distances from each point to the reference plane are relatively consistent, indicating that the surface of the area is relatively flat.

[0093] Specifically, the standard deviation of the input data can be calculated using the built-in MATLAB function std. Figure 7 As shown;

[0094] S24, adjusting the number of simulation points in each point cloud grid area according to the surface complexity of each point cloud grid area, and then exporting the position coordinate data of the adjusted simulation points as a simulation point data file; the adjustment is based on: the number of simulation points allocated in the point cloud grid area is proportional to its surface complexity;

[0095] The number of simulation points is dynamically adjusted according to the surface complexity (i.e. standard deviation) of each point cloud mesh area. More simulation points are allocated to areas with higher complexity to improve simulation accuracy; conversely, fewer points are allocated to areas with lower complexity.

[0096] Traverse the discrete points in each point cloud grid area. If the complexity of the point is greater than 0, use the round(a*discrete point complexity) function to get the number of simulation points corresponding to the point; if the complexity of the discrete point is less than or equal to 0, set the simulation point corresponding to the point to 0;

[0097] Wherein a is an adjustment factor, and the value of a is selected between (0, 1) according to actual needs. The smaller the value of a is, the larger the number of simulation points obtained is. Preferably, the value of a in this embodiment is 0.1. The round function is used to round the number of simulation points.

[0098] In this example, (a*standard deviation) is used as the proportional factor to determine the number of simulation points. The higher the complexity, the more simulation points are allocated. Figure 8 shown.

[0099] The simulation point data file is a CSV file.

[0100] S25, after setting the simulation conditions, import the simulation point data file, and then perform numerical simulation based on the multiphase flow method and fit to obtain the optimal focus distance surface;

[0101] S251. Prepare the Fluent simulation environment: Use Ansys Workbench to import the 3D model of the workpiece into the pre-processor of the Fluent software, create the fluid domain and set the boundary conditions, and set the required physical model, material properties, boundary conditions, initial conditions, etc. in Fluent.

[0102] S252. Import simulation points and automatically perform simulation: After the boundary conditions are set, use the Fluent text user interface command to load the CSV file, read the location information of the simulation points, and automatically perform numerical simulation based on the multiphase flow method at each simulation point to obtain the optimal defocus value corresponding to each point:

[0103] The multiphase flow method is a numerical simulation technology used to simulate the distribution and movement of abrasive particles in liquid media.

[0104] Multiphase flow technology is an existing technology, and reference may be made to the literature: Prosperetti A. Computational Methods for Multiphase Flow [M]. Cambridge university press, 2009.

[0105] The "Ansys Fluent" simulation software described in the embodiment can directly call the multiphase flow method to perform relevant numerical simulation of the fluid.

[0106] S253, exporting simulation results and fitting to obtain an optimal defocus surface;

[0107] After the simulation is completed, the optimal defocus data for each simulation point is exported, and then these points are processed in MATLAB, and a "optimal defocus surface" covering the workpiece surface is generated through a fitting algorithm. This surface represents the optimized simulation path along the Z direction.

[0108] a. After the simulation is completed, the optimal defocus data is exported from the Fluent software:

[0109] b. Read the optimal defocus data through MATLAB software, and fit the optimal defocus data of each simulation point to the optimal defocus surface through the griddata function;

[0110] The griddata function can fit discrete lattice data into a continuous surface, which represents the optimal defocus value for each point on the workpiece surface.

[0111] S26, performing path planning according to the optimal focus distance surface to obtain an optimized laser scanning path;

[0112] After the optimized surface is generated, the path planning adopts the following strategies: for the path planning in the X and Y directions, traditional strategies such as zigzag and straight can be used;

[0113] Zigzag path such as Fig. 9 As shown, start from one side, gradually move to the other side, and then return, forming a zigzag movement trajectory.

[0114] A straight path such as Fig.10 As shown, the laser moves forward and backward along a straight line, the starting point and the end point of the path are fixed.

[0115] However, in the Z direction, the optimal defocus surface obtained by fitting is used to ensure that the path height is dynamically adjusted according to the complexity of the workpiece surface, thereby achieving accurate laser processing path optimization.

[0116] Preferably, during path planning, a zigzag strategy is adopted in the X and Y directions, the Z direction is adjusted according to the optimal defocus surface, and interpolation is performed in the Z direction through the interp2 function, and finally an optimized laser scanning path is obtained.

[0117] The interp2 function is a function used for two-dimensional interpolation in MATLAB. Its main function is to generate a smooth continuous function in two-dimensional space based on known discrete data points.

[0118] In this embodiment, the optimal defocus surface is generated by interpolating the defocus data of each simulation point. The interp2 function can interpolate a continuous optimal defocus surface in the Z direction based on known discrete points, thereby filling in the data gaps.

[0119] Through the above steps, the present invention realizes a complete process from simulation point planning, automated simulation to path optimization. The simulation software Fluent automatically calculates the optimal defocus value at each specified position, and then MATLAB fits the optimal defocus value surface according to the simulation results of these points, and finally optimizes the scanning path through the path planning algorithm to improve the polishing accuracy and efficiency.

[0120] Traditional path planning strategies in the X and Y directions can effectively cover the workpiece surface and ensure uniform polishing. For example, a zigzag path covers the entire area with a back-and-forth movement, while a straight path is used for fine processing of specific areas.

[0121] In this implementation, path optimization is mainly reflected in the Z direction, that is, the adjustment of the laser defocus. As mentioned above, first, the point cloud data of the workpiece surface is obtained by discretizing the three-dimensional model of the workpiece, calculating the surface complexity, and dynamically allocating simulation points according to the complexity. Subsequently, the Fluent simulation environment is used to perform numerical simulation based on the multiphase flow method on the set simulation points. By calculating the optimal defocus of each simulation point, the optimal defocus data corresponding to each point is obtained, and these discrete data are fitted into a continuous optimal defocus surface. This surface represents the optimal defocus of each point on the workpiece surface. According to the obtained optimal defocus surface, the focal position of the laser can be dynamically adjusted in the Z direction during path planning to ensure that the laser always remains at the optimal defocus position during the processing process, thereby achieving precise polishing effect.

[0122] This embodiment obtains point cloud data of the workpiece surface and analyzes the surface complexity, and processes the workpiece surface in regions according to the complexity. This method optimizes the simulation points and laser scanning paths to ensure that different regions obtain appropriate focal length surfaces, thereby enhancing the uniformity of cavitation and significantly improving the polishing quality and efficiency.

[0123] S3, polishing process: start the phased array control system, phased acoustic wave array and optical detection system, and after the abrasive particles are evenly suspended, start the laser and polish the workpiece according to the optimized scanning path.

[0124] At the same time, the present invention also uses a phased array acoustic suspension system to accurately control the position of the abrasive particles in the liquid medium, so that it can move synchronously with the laser focus, ensuring high precision and consistency during the polishing process. Fig.11 As shown, the phased acoustic wave arrays 5 and 9 are composed of a plurality of acoustic wave emitting units 5 - 1 , and each acoustic wave emitting unit 5 - 1 can be controlled individually.

[0125] The phased array control system 11 is connected to the phased acoustic wave arrays 5 and 9 and is used to adjust the frequency, amplitude and phase of the acoustic waves generated by the acoustic wave emitting unit to achieve precise suspension control of the abrasive particles.

[0126] Specifically, the computer control system 12 is connected to the three-dimensional motion platform 1, the laser 2, the phased array control system 11 and the optical detection system 13 to control the movement of the three-dimensional motion platform, the parameters of the high-energy pulse laser 3 generated by the laser 2, the processing of the images taken by the optical detection system 13, and the real-time parameter adjustment of the phased array control system 11.

[0127] like Fig.12 As shown in the figure, the principle of acoustic suspension is to use the radiation pressure of sound waves to form a standing wave field in the liquid, in which the peaks and troughs of the sound waves appear alternately. In the liquid medium, the abrasive particles are guided to the node position of the sound wave in the sound field, that is, the area where the pressure of the sound wave and the gravity of the liquid reach a balance, so that the abrasive particles are suspended in the liquid.

[0128] The phased array control system adjusts the acoustic wave parameters of the phased acoustic wave array, including frequency, amplitude and phase, according to real-time data to ensure uniform suspension of the abrasive particles in the liquid. The phased array control system adjusts the acoustic wave parameters in real time through feedback signals to compensate for possible uneven suspension of the abrasive particles.

[0129] In order to achieve precise control of the abrasive particle suspension position and enable the abrasive particles to always follow the movement of the laser focus, a proportional-integral-differential (PID) control algorithm is introduced into the phased array control system 11 .

[0130] The PID control algorithm ensures that the abrasive particles can be stably suspended in the sound field and accurately follow the changes in the laser focus by adjusting the output parameters (including frequency, phase and amplitude) of each acoustic wave emitting unit. This is existing technology and will not be described in detail here.

[0131] Specifically, Fig.13 As shown, the specific process of the PID control algorithm in this embodiment to control the abrasive particle suspension position is as follows:

[0132] Initialization and input: When the system starts, the initial desired position of the laser focus is first input according to the optimized scanning plan. The acoustic wave emission unit is initialized to the reference state, and the acoustic wave parameters are set to the initial values.

[0133] Real-time error calculation: The image of the abrasive particles in the liquid is captured by a high-speed camera, and the actual suspension position of the abrasive particles is detected in real time by combining image processing technology. The error between the abrasive particles and the expected position of the laser focus is calculated using image processing algorithms.

[0134] PID adjustment: Use the PID control formula to calculate the control input at the current moment and adjust the frequency, phase and amplitude of the acoustic wave transmitting unit to minimize the position error.

[0135] Output and adjustment: The calculated control input is used to adjust the output of each acoustic wave emission unit in real time, so that the abrasive particle suspension position gradually approaches the laser focus.

[0136] Feedback and iteration: The system continuously monitors the position of the abrasive particles and continuously adjusts the acoustic wave parameters through the PID control loop to ensure the stability and followability of the abrasive particle position.

[0137] The computer control system uses a proportional-integral-differential (PID) control algorithm to optimize the position of the abrasive particle suspension. The PID control algorithm calculates the control error by monitoring the distance between the position of the abrasive particle and the laser focus in real time, and adjusts the output of the phased acoustic array to ensure that the abrasive particle is accurately suspended near the laser focus. The PID controller continuously adjusts the frequency, phase and amplitude of the acoustic wave based on the real-time position data of the abrasive particle to achieve precise control of the abrasive particle position and ensure the stability and consistency of the abrasive particle during the polishing process.

[0138] This embodiment provides an abrasive jet polishing method based on simulation path optimization and acoustic wave control, which is efficient, accurate and highly adaptable. The present invention optimizes the path through numerical simulation, combines the phased acoustic wave array to achieve uniform suspension of abrasive particles, fully considers the influence of the workpiece wall shape on the cavitation pulsation process by laser-induced cavitation polishing technology, and significantly improves the polishing quality and efficiency.

[0139] This specification is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of this specification. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 Processes Multiple processes and / or boxes Figure 1 A device that has the functions specified in one or more boxes.

[0140] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0141] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0142] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and it is intended that all changes that fall within the meaning and scope of equivalent elements are included in the present invention.

Claims

1. An abrasive jet polishing method based on simulation path optimization and acoustic wave control, characterized in that: The method is based on an abrasive jet polishing device based on simulation path optimization and acoustic wave control, the device comprising: a three-dimensional motion platform, a laser located on the three-dimensional motion platform, a high-energy pulse laser generated by the laser, a water tank located below the laser, a fixture located at the bottom of the water tank for clamping a workpiece, a phased acoustic wave array located on both sides of the water tank, a phased array control system for controlling the phased acoustic wave array and an optical detection system for monitoring the position of abrasive particles; a computer control system connected to the laser and the three-dimensional motion platform, used for numerical simulation calculation, laser scanning path planning and processing parameter adjustment, and controlling the three-dimensional motion platform to drive the laser to move; the computer control system is also connected to the phased array control system and the optical detection system, used for real-time monitoring of the position of abrasive particles and controlling acoustic wave parameters; comprising the following steps: S1, placing a workpiece and preparing a liquid medium containing abrasive particles: firstly placing the workpiece in the water tank and fixing the workpiece with a fixture, then adding pure water to the water tank, and finally adding abrasive particles to the water tank; S2, setting processing parameters and planning scanning path: setting relevant parameters of the laser through the computer control system; obtaining the surface point cloud data of the workpiece through the computer control system to calculate its surface complexity, and then dynamically allocating the workpiece simulation points according to the surface complexity, and finally obtaining the optimized laser scanning path based on the simulation points based on the multiphase flow method; S3, polishing process: start the phased array control system, phased acoustic wave array and optical detection system, and after the abrasive particles are evenly suspended, start the laser and polish the workpiece according to the optimized laser scanning path.

2. The abrasive jet polishing method according to claim 1, characterized in that: Step S2 specifically includes: S21, discretizing the three-dimensional model of the workpiece to obtain point cloud data of the workpiece surface; S22, dividing the workpiece surface point cloud data into a plurality of point cloud grid areas according to the range of the workpiece surface point cloud data on the X axis and the Y axis; S23, calculating the surface complexity of each point cloud grid region by the distance from the discrete points in the point cloud grid region to the reference surface; the surface complexity is the set of complexities of the discrete points in the point cloud grid region; S24, adjusting the number of simulation points in each point cloud grid area according to the surface complexity of each point cloud grid area, and then exporting the position coordinate data of the adjusted simulation points as a simulation point data file; the adjustment is specifically: the simulation points allocated in the point cloud grid area are proportional to its surface complexity; S25, after setting the simulation conditions, import the simulation point data file, and then perform numerical simulation based on the multiphase flow method and fit to obtain the optimal focus distance surface; S26. Perform path planning based on the optimal focal length surface to obtain an optimized laser scanning path.

3. The abrasive jet polishing method according to claim 2, characterized in that: Step S21 specifically includes: S211, using the stlread function in MATLAB to read the workpiece 3D model file from the specified path and extract the vertex data of the model; S212, using the vertices function to discretize the vertex data according to a preset number of controlled discrete points to obtain workpiece surface point cloud data.

4. The abrasive jet polishing method according to claim 2, characterized in that: Step S22 specifically includes: S221, obtaining the maximum value and minimum value of the workpiece surface point cloud data in the X direction, the maximum value and minimum value in the Y direction; S222, dividing the workpiece surface point cloud data into two-dimensional point cloud grid areas by using the linspace function according to the maximum value in the X direction, the minimum value in the X direction, the maximum value in the Y direction, and the minimum value in the Y direction.

5. The abrasive jet polishing method according to claim 2, characterized in that: Step S23 specifically includes: S231, selecting a plane in the Z-axis direction as a reference plane; S232. Traverse all point cloud grid areas. If the number of discrete points in the point cloud grid area is greater than 0, calculate the distance from each discrete point in the point cloud grid area to the reference plane, and calculate the standard deviation of the distance as the complexity of the discrete point, and then obtain the surface complexity of the point cloud grid area; if the number of discrete points in the point cloud grid area is 0, the surface complexity of the point cloud grid area is 0.

6. The abrasive jet polishing method according to claim 2, characterized in that: The method of adjusting the number of simulation points in each point cloud grid area according to the surface complexity of each point cloud grid area in step S24 is specifically as follows: traverse the discrete points of each point cloud grid area, and if the complexity of the point is greater than 0, use the round(a*discrete point complexity) function to obtain the number of simulation points corresponding to the point; if the complexity of the discrete point is less than or equal to 0, set the simulation point corresponding to the point to 0; wherein a is the adjustment factor.

7. The abrasive jet polishing method according to claim 2, characterized in that: Step S25 specifically includes: S251. Prepare Fluent simulation environment: Use Ansys Workbench to import the workpiece 3D model into Fluent preprocessor, create fluid domain and set boundary conditions, and set the required physical model, material properties, boundary conditions, initial conditions, etc. in Fluent; S252, import simulation points and automatically perform simulation: after the boundary conditions are set, use Fluent to load the simulation point data file, read the position information of the simulation point, and automatically perform numerical simulation based on the multiphase flow method at each simulation point, so as to obtain the optimal defocus value corresponding to each point; S253, exporting simulation results and fitting to obtain an optimal defocus surface: after the simulation is completed, the optimal defocus data is exported and then read through MATLAB, and the optimal defocus of each simulation point is fitted through the griddata function to obtain an optimal defocus surface.

8. The abrasive jet polishing method according to claim 2, characterized in that: Step S26 specifically includes: when planning the path, a zigzag strategy is adopted in the X and Y directions, the Z direction is adjusted according to the optimal defocus surface, and interpolation is performed in the Z direction through the interp2 function, and finally an optimized laser scanning path is obtained.

9. The abrasive jet polishing method according to claim 1, characterized in that: The phased-control acoustic wave array is composed of a plurality of acoustic wave emitting units, each of which can be controlled individually; the phased-control array control system is connected to the phased-control acoustic wave array and is used to adjust the frequency, amplitude and phase of the acoustic waves generated by the acoustic wave emitting units to achieve precise suspension control of the abrasive particles.

10. The abrasive jet polishing method according to claim 1, characterized in that: The computer control system utilizes a PID control algorithm to optimize the position of the abrasive particle suspension.

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