Method and System for Laser Scanning Path of Additive Manufacturing Based on Finite Element Simulation

Abstract

The present invention relates to a method and system for laser scanning path of additive manufacturing based on finite element simulation. The method includes reading the three-dimensional coordinates of each triangular facet and the normal vector of the triangular facet in the part model file to be printed; screening to obtain the triangular facets intersecting with the imaginary slicing plane; solving the intersection points of the slicing plane and the triangular facets to obtain the contour point matrix of the part on the slicing plane; generating filling lines in the reduced slicing plane, and screening the filling lines intersecting with the part contour according to the contour point matrix; calculating the intersection points of the filling lines and the part contour to obtain the intersection point matrix on the slicing plane; importing the laser scanning path, processing time and laser state into the finite element software to simulate the manufacturing of parts by selective laser melting. The present invention uses MATLAB to realize the reading, slicing and filling of the printing model, and obtains the laser scanning path, which is beneficial to improving the accuracy of simulating the manufacturing of parts by selective laser melting and reducing the simulation difficulty.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a method and system for simulating a laser scanning path of additive manufacturing based on finite element simulation. Background Art

[0002] At present, there are two methods for simulating the laser scanning path in the selective laser melting process through finite element software. One is to directly define the laser scanning path through a subroutine. For example, ANSYS uses the APDL command line to define the movement of the heat source, and ABAQUS uses the DFLUX user subroutine to define the heat source as a function of position and time. Although this method is straightforward, on the one hand, the development and use of these command lines and subroutines usually require a considerable amount of professional knowledge, increasing the learning cost; on the other hand, this method is only suitable for defining relatively simple laser scanning paths. Once the laser scanning path becomes complex, the workload of writing code will increase significantly, thereby increasing the error rate. The other method is to import the printed part model into 3D printing software, and after selecting the scanning strategy, the Gcode code of the laser scanning path can be obtained, and then the Gcode code is imported into the finite element software to simulate the movement of the heat source. The advantage of this method is that it is simple and feasible and the path is visual, but there are also many restrictions: on the one hand, most of the relatively mature 3D printing software available on the market is based on filamentous materials (such as PLA, nylon, etc.). Limited by the properties of the filaments (the diameter is millimeter-level, and the continuity of the filaments is highly emphasized during the printing process), the laser scanning path automatically generated by the software is different from the actual selective laser melting process, especially for thin-walled parts and tubular parts; on the other hand, due to the different basic technical principles of filament 3D printing and selective laser melting, there are significant differences in the scanning strategies of the two, and modifying the Gcode code is a difficult and cumbersome task.

[0003] Therefore, there is an urgent need to provide an innovative method for simulating the laser scanning path of additive manufacturing to overcome the above-mentioned technical defects existing in the prior art. Summary of the Invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the technical defects existing in the prior art, and to propose a method and system for simulating the laser scanning path of additive manufacturing based on finite element simulation, which is committed to using MATLAB to realize the reading, slicing and filling of the printed model, obtain the laser scanning path, and then directly generate the inp file for simulation, which is beneficial to improving the accuracy of simulating the manufacturing of parts by selective laser melting, reducing the simulation difficulty, and providing a feasible solution for simulating a series of changes in the entire printing process.

[0005] To solve the above technical problems, the present invention provides a method for simulating the laser scanning path of additive manufacturing based on finite element simulation, including the following steps:

[0006] S1: Using MATLAB to read the three-dimensional coordinates of each vertex of each triangular face and the normal vector of each triangular face in the part model file to be printed;

[0007] S2: Imagine generating multiple equally spaced and infinitely large slice planes, and based on the slice height position and the three-dimensional coordinates of each vertex of the triangular facet, screen out all the triangular facets that intersect with the slice planes;

[0008] S3: Solve all the intersection points between the slicing plane and the triangular face according to the spatial coordinate system, remove the overlapping intersection points, and obtain the contour points of the part on the single-layer slicing plane;

[0009] S4: Repeat step S3 to obtain the contour points of the part on each slice plane and generate a contour point matrix;

[0010] S5: imagining a printing platform that can accommodate the entire part according to the size of the part to be printed, and reducing the infinitely large slicing plane imagined in step S1 to the size of the printing platform;

[0011] S6: generating a plurality of equally spaced fill lines in the reduced slice plane, and selecting fill lines intersecting with the part contour according to the contour point matrix obtained in step S4;

[0012] S7: Calculate the intersection points of the screened fill lines and the part contour to obtain a matrix of intersection points of the fill lines and the part contour on a slice plane;

[0013] S8: Repeat steps S6 and S7 to obtain the intersection matrix of the fill lines and the part contours on all slice planes, and the lines between the intersections are the laser scanning paths;

[0014] S9: Write the laser scanning path, processing time and laser status into the same matrix and output it as an inp file using MATLAB;

[0015] S10: Import the inp file into the finite element software to simulate the entire process of laser selective melting to manufacture parts.

[0016] In one embodiment of the present invention, before using MATLAB to read the part model to be printed, the part model is saved as an stl format file.

[0017] In one embodiment of the present invention, in step S2, a method for imaginarily generating a plurality of equally spaced and infinitely large slice planes comprises:

[0018] Generates multiple equally spaced, infinitely large slice planes in the z-direction.

[0019] In one embodiment of the present invention, in step S2, the method of screening all triangular facets intersecting with the slice plane according to the height position of the slice and the three-dimensional coordinates of each vertex of the triangular facet includes:

[0020] Create a triangle list for each slicing plane;

[0021] On each slice plane, all triangular facets intersecting with the slice plane are screened, and all data of the screened triangular facets are recorded in the triangle list of the slice plane.

[0022] In one embodiment of the present invention, a method for screening all triangular facets intersecting with each slice plane on each layer of the slice plane includes:

[0023] When the z coordinate of a vertex of a triangular patch is lower than the z coordinate of a slice plane, and the z coordinate of another vertex of the triangular patch is higher than the z coordinate of the slice plane, the triangular patch intersects the slice plane.

[0024] In one embodiment of the present invention, in step S6, the method of obtaining the fill line intersecting with the part contour according to the contour point matrix includes:

[0025] According to the contour point matrix, the contour points of the part on a slice plane are obtained, and the contour points are connected in sequence to obtain the edge of the part contour on the slice plane. It is determined whether the two vertices on the edge of the part contour are on the same side of the fill line. If so, the fill line does not intersect with the part contour. If not, the fill line intersects with the part contour.

[0026] In addition, the present invention also provides a system for simulating an additive manufacturing laser scanning path based on finite element method, comprising:

[0027] A data reading module is used to read the three-dimensional coordinates of each vertex of each triangular face and the normal vector of the triangular face in the part model file to be printed by using MATLAB;

[0028] The part slicing module is used to generate multiple equally spaced and infinitely large slicing planes. According to the height position of the slices and the three-dimensional coordinates of each vertex of the triangular facets, all the triangular facets intersecting with the slicing planes are screened out; all the intersection points of the slicing planes and the triangular facets are solved according to the spatial coordinate system, and the overlapping intersection points are eliminated to obtain the contour points of the part on each layer of the slicing plane and generate a contour point matrix;

[0029] A part filling module, which is used to imagine a printing platform that can accommodate the entire part according to the size of the part to be printed, and reduce the imaginary infinite slicing plane to the size of the printing platform; generate a plurality of equally spaced filling lines in the reduced slicing plane, and screen out the filling lines that intersect with the part contour according to the contour point matrix; calculate the intersection points of the screened filling lines and the part contour to obtain the intersection point matrix of the filling lines and the part contour on all slicing planes, and the connection between the intersection points is the laser scanning path.

[0030] A laser scanning simulation module, which is used to write the laser scanning path, processing time and laser state into the same matrix, and output it as an inp file using MATLAB; import the inp file into finite element software to simulate the entire process of manufacturing parts by selective laser melting.

[0031] In an embodiment of the present invention, in the part filling module, the method for screening out the filling lines that intersect with the part contour according to the intersection point matrix includes:

[0032] Obtain the contour points of the part on a slicing plane according to the intersection point matrix, connect the contour points in sequence to obtain the edge of the part contour on this slicing plane, and judge whether the two vertices on the edge of the part contour are on the same side of the filling line. If so, the filling line does not intersect with the part contour; if not, the filling line intersects with the part contour.

[0033] Moreover, the present invention also provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of the above method are implemented.

[0034] In addition, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the steps of the above method are implemented.

[0035] The above technical solutions of the present invention have the following advantages compared with the prior art:

[0036] 1. A method and system for simulating a laser scanning path for additive manufacturing based on finite element. It is committed to using MATLAB to read, slice and fill a printing model to obtain a laser scanning path, and then directly generate an inp file for simulation. This is beneficial to improving the accuracy of simulating the manufacturing of parts by selective laser melting, reducing the simulation difficulty, and providing a feasible solution for simulating a series of changes in the entire printing process.

[0037] 2. For the method and system for additive manufacturing laser scanning path based on finite element simulation according to the present invention, users do not need to specifically learn an obscure language (such as Fortran) for subroutine development. They only need to have a certain MATLAB programming ability to obtain the laser scanning path.

[0038] 3. For the method and system for additive manufacturing laser scanning path based on finite element simulation according to the present invention, it can obtain any laser scanning path that is exactly the same as the actual experimental process, thereby improving the accuracy of subsequent finite element simulation.

[0039] 4. For the method and system for additive manufacturing laser scanning path based on finite element simulation according to the present invention, the method of using MATLAB to read stl files and export inp files is very mature. Using MATLAB, the laser scanning path can also be observed in real time by plotting, which is convenient for discovering problems and making modifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to specific embodiments of the present invention in conjunction with the drawings, where

[0041] Figure 1 is a schematic flow chart of a method for additive manufacturing laser scanning path based on finite element simulation proposed in an embodiment of the present invention.

[0042] Figure 2 is a schematic diagram of Exemplary Case 1 proposed in an embodiment of the present invention. Among them, a is a square model, b is a model slice, c is the filling of the second layer slice, and d is the model filling.

[0043] Figure 3 is a schematic diagram of Exemplary Case 2 proposed in an embodiment of the present invention. Among them, a is a cylinder model, b is a model slice, c is the filling of the second layer slice, and d is the model filling.

[0044] Figure 4 is a schematic diagram of Exemplary Case 3 proposed in an embodiment of the present invention. Among them, a is a hollow cylinder model, b is a model slice, c is the filling of the second layer slice, and d is the model filling. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] The following further illustrates the present invention in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the examples given are not intended to limit the present invention.

[0046] Refer to Figure 1 and Figure 2As shown in the figure, an embodiment of the present invention provides a method for simulating a laser scanning path for additive manufacturing based on finite element, including the following steps:

[0047] S1: Save the part model as an stl format file, and use MATLAB to read the three-dimensional coordinates of each vertex of each triangular facet and the normal vector of the triangular facet in the part model file to be printed;

[0048] S2: Hypothetically generate multiple equally spaced and infinitely large slicing planes, and filter out all triangular facets that intersect with the slicing plane according to the height position of the slice and the three-dimensional coordinates of each vertex of the triangular facet;

[0049] S3: Solve all the intersection points of the slicing plane and the triangular facet in the space coordinate system, and eliminate the overlapping intersection points to obtain the contour points of the part on the single-layer slicing plane;

[0050] S4: Repeat step S3 to obtain the contour points of the part on each slicing plane and generate a contour point matrix;

[0051] S5: Hypothetically assume a printing platform that can accommodate the entire part according to the size of the part to be printed, and reduce the infinitely large slicing plane assumed in step S1 to the size of the printing platform;

[0052] S6: Generate multiple equally spaced filling lines in the reduced slicing plane, and filter out the filling lines that intersect with the part contour according to the contour point matrix obtained in step S4;

[0053] S7: Calculate the intersection points of the filtered filling lines and the part contour to obtain an intersection point matrix of the filling lines and the part contour on one slicing plane;

[0054] S8: Repeat steps S6 and S7 to obtain the intersection point matrix of the filling lines and the part contour on all slicing planes, and the connection between the intersection points is the laser scanning path;

[0055] S9: Write the laser scanning path, processing time, and laser state into the same matrix, and use MATLAB to output it as an inp file;

[0056] S10: Import the inp file into finite element software to simulate the entire process of manufacturing the part by selective laser melting.

[0057] A method for simulating a laser scanning path for additive manufacturing based on finite element according to the present invention is dedicated to using MATLAB to realize the reading, slicing, and filling of the printing model, obtain the laser scanning path, and then directly generate an inp file for simulation, which is beneficial to improving the accuracy of simulating the manufacturing of parts by selective laser melting, thereby reducing the simulation difficulty and providing a feasible solution for simulating and studying a series of changes in the entire printing process.

[0058] In step S2, the actual powder layer thickness of the part is used to generate a series of equally spaced and infinitely large slice planes, and the height positions of these slice planes, i.e., the z coordinates of the slice planes, are obtained. For the convenience of observation and description, the preferred powder layer thickness of this embodiment is 1 mm, and the part forming direction is upward along the z axis.

[0059] Among them, in step S2, the method of screening all triangular patches intersecting with the slice plane according to the height position of the slice and the three-dimensional coordinates of each vertex of the triangular patch includes: creating a triangle list for each slice plane; screening all triangular patches intersecting with the slice plane on each layer of the slice plane, and recording all data of the screened triangular patches in the triangle list of the slice plane.

[0060] Furthermore, the method of screening all triangular facets intersecting with the slicing plane on each layer of the slicing plane includes: when the z coordinate of a vertex of a triangular facet is lower than the z coordinate of a slicing plane, and the z coordinate of another vertex of the triangular facet is higher than the z coordinate of the slicing plane, the triangular facet intersects with the slicing plane.

[0061] Among them, in step S6, the method of obtaining a fill line that intersects with the part contour by screening according to the contour point matrix includes: obtaining contour points of the part on a slicing plane according to the contour point matrix, connecting the contour points in sequence to obtain the edge of the part contour on the slicing plane, and judging whether two vertices on the edge of the part contour are on the same side of the fill line, if so, the fill line does not intersect with the part contour, if not, the fill line intersects with the part contour.

[0062] The above steps S2-S4 are to slice the printed part model to obtain the contour points of the part (including the external contour and the internal contour). Many scholars have conducted in-depth research on slicing algorithms, which greatly improved the computing efficiency. The present invention adopts the algorithm proposed by scholar Sunil Bhandari in the article "A graph-based algorithm for slicing unstructured mesh files" in the step of slicing the printed part model.

[0063] The method of simulating the laser scanning path of additive manufacturing based on finite element method described in the present invention does not require the user to specially learn a relatively obscure language (such as Fortran) for subroutine development, and only needs to have a certain MATLAB programming ability to obtain the laser scanning path.

[0064] A method for finite element simulation-based additive manufacturing laser scanning path according to the present invention can obtain arbitrary laser scanning paths that are exactly the same as the actual experimental process, thereby improving the accuracy of subsequent finite element simulations.

[0065] A method for finite element simulation-based additive manufacturing laser scanning path according to the present invention has a mature method of using MATLAB to read stl files and export inp files. Using MATLAB, the laser scanning path can also be observed in real time through plotting, which is convenient for discovering problems and making modifications.

[0066] The following elaborates in detail a method for finite element simulation-based additive manufacturing laser scanning path proposed by the present invention through three exemplary cases.

[0067] The filling lines (i.e., laser scanning paths) of all the following exemplary cases are designed according to the existing research results of current selective laser melting manufacturing of nickel-titanium alloy parts: between each layer of sliced planes, the filling lines are at an angle of 67° to each other.

[0068] Exemplary Case 1: A cube of 10 x 10 x 10 mm 3 cube

[0069] (1) Save the cube model as an stl format file, as shown in Figure 2 a.

[0070] (2) Use MATLAB to read the three-dimensional coordinates of each vertex of each triangular patch and the normal vector of the triangular patch in the stl file.

[0071] (3) Assume the powder spreading layer thickness is 1 mm, and generate a series of sliced planes with a spacing of 1 mm in the z-axis direction, as shown in Figure 2 b.

[0072] (4) Taking the first layer of sliced plane (z = 1 mm) as an example, traverse all triangular patches. When the minimum z coordinate in a certain triangular patch is less than 1 mm and the maximum z coordinate is greater than 1 mm, it means that this triangular patch intersects with this layer of sliced plane, and it is put into the triangular list matrix of this layer; loop through each layer of sliced plane in this way to obtain the triangular list matrix of each layer of sliced plane;

[0073] (5) For a single-layer slice plane, sequentially extract the triangular facets intersecting with it obtained in step (4), and calculate the intersection points between the slice plane and the triangular facets. The method for finding the intersection points is as follows: Assume the slice plane is z = c (c is a constant), and the three vertex coordinates of a triangular facet with an intersection are V1(x1, y1, z1), V2(x2, y2, z2), V3(x3, y3, z3), and the intersection coordinates are P1(x4, y4, z4), P2(x5, y5, z5). Then x4 = x1 + t * (x2 - x1), y4 = y1 + t * (y2 - y1), z4 = c, where t = (c - z1) / (z2 - z1).

[0074] (6) Repeat step (5) to obtain the intersection points between each layer of slice plane and the triangular facets, which are the external contour points of the cube, and generate a contour point matrix.

[0075] (7) Imagine a 20 x 20mm 2 printing platform, that is, the size of each slice plane is also 20 x 20mm. 2 .

[0076] (8) To facilitate observation and reduce the operation time, assume the filling line spacing (laser scanning spacing) is 1mm. If the filling lines of the first layer slice plane are parallel to the x-axis, then the filling lines of the second layer slice plane form an angle of 67° with the x-axis. Taking the second layer as an example, generate a series of filling lines with an angle of 67° with the x-axis and a spacing of 1mm to fill the entire slice plane imagined in step (7). According to the contour point matrix obtained in step (6), find the contour points on the second layer slice plane, and filter and retain the filling lines intersecting with the part contour according to the contour points.

[0077] (9) Calculate the intersection points between the filling lines and the cylinder contour, and save them as an intersection point matrix. The connection lines between these intersection points are the laser scanning paths. The laser scanning path on the second layer slice plane is as Figure 2 shown in c.

[0078] (10) Repeat steps (8) and (9) to obtain the intersection point matrices of the filling lines and the cylinder contour on all slice planes. The overall filling effect of the part is as Figure 2 shown in d.

[0079] (11) According to the actual manufacturing process, write the processing time, laser scanning path, and laser state into the same matrix, and then output it as an inp file by MATLAB.

[0080] (12) Import the inp file into the AM Modeler plug-in of the finite element software ABAQUS to simulate the entire process of manufacturing a cylinder part by selective laser melting.

[0081] Exemplary Case 2: A cylinder with a bottom diameter of 10 mm and a height of 10 mm

[0082] The specific steps of this embodiment are exactly the same as those of Embodiment 1. The reason for choosing the cylinder model is that the external contour of the cylinder model is more complex than that of the cube. When finding the intersection points of the filling line and the external contour, it is easier to have special situations where the filling line is parallel or coincides with the local external contour, which is very suitable for testing whether there are defects in the MATLAB program. The specific steps are as follows:

[0083] (1) Save the cylinder model as an stl format file, as shown in Figure 3 Figure a.

[0084] (2) Use MATLAB to read the three-dimensional coordinates of each vertex of each triangular facet and the normal vector of the triangular facet in the stl file.

[0085] (3) Assume that the powder spreading layer thickness is 1 mm, and generate a series of slicing planes with a spacing of 1 mm in the z-axis direction, as shown in Figure 3 Figure b.

[0086] (4) Taking the first layer of slicing plane as an example (z = 1 mm), traverse all triangular facets. When the minimum z coordinate in a certain triangular facet is less than 1 mm and the maximum z coordinate is greater than 1 mm, it means that this triangular facet intersects with this layer of slicing plane, and it is put into the triangular list matrix of this layer. Loop through each layer of slicing plane in this way to obtain the triangular list matrix of each layer of slicing.

[0087] (5) For a single layer of slicing plane, sequentially take out the triangular facets that intersect with it obtained in step (4), and calculate the intersection points of the slicing plane and the triangular facets. The method for finding the intersection points is as follows: Assume that the slicing plane is z = c (c is a constant), and the three vertex coordinates of a triangular facet with an intersection point are V1(x1, y1, z1), V2(x2, y2, z2), V3(x3, y3, z3), and the intersection coordinates are P1(x4, y4, z4), P2(x5, y5, z5). Then x4 = x1 + t * (x2 - x1), y4 = y1 + t * (y2 - y1), z4 = c, where t = (c - z1) / (z2 - z1).

[0088] (6) Repeat step (5) to obtain the intersection points of each layer of slicing plane and the triangular facets, that is, the external contour points of the cylinder, and generate a contour point matrix.

[0089] (7) Imagine a 20 x 20 mm 2 printing platform, that is, the size of each slicing plane is also 20 x 20 mm 2 .

[0090] (8) For the convenience of observation and to reduce the operation time, assume that the filling line spacing (laser scanning spacing) is 1 mm. If the filling lines of the first layer of the sliced plane are parallel to the x-axis, then the filling lines of the second layer of the sliced plane form an angle of 67° with the x-axis. Taking the second layer as an example, generate a series of filling lines that form an angle of 67° with the x-axis and have a spacing of 1 mm to fill the entire sliced plane imagined in step (7). According to the contour point matrix obtained in step (6), find the contour points on the sliced plane of the second layer, and screen the filling lines that intersect with the part contour according to the contour points and retain them.

[0091] (9) Calculate the intersection points of the filling lines and the cylinder contour and save them as an intersection point matrix. The connection lines between these intersection points are the laser scanning paths. The laser scanning paths on the sliced plane of the second layer are as Figure 3 shown in c.

[0092] (10) Repeat steps (8) and (9) in a loop to obtain the intersection point matrix of the filling lines and the cylinder contour on all sliced planes. The overall filling effect of the part is as Figure 3 shown in d.

[0093] (11) According to the actual manufacturing process, write the processing time, laser scanning path, and laser state into the same matrix, and then output it as an inp file by MATLAB.

[0094] (12) Import the inp file into the AM Modeler plug-in of the finite element software ABAQUS to simulate the entire process of manufacturing the cylinder part by selective laser melting.

[0095] Exemplary Case 3: A hollow cylinder with an outer bottom diameter of 10 mm, an inner diameter of 6 mm, and a height of 10 mm

[0096] The specific steps of this exemplary case only have some differences from those of Exemplary Case 1 in steps (5) and (9). Since the hollow cylinder has not only an external contour but also an internal contour, the specific differences are as follows:

[0097] (1) Save the hollow cylinder model as an stl format file, as Figure 4 shown in a.

[0098] (2) Use MATLAB to read the three-dimensional coordinates of each vertex of each triangular facet and the normal vector of the triangular facet in the stl file.

[0099] (3) Assume that the powder spreading layer thickness is 1 mm, and generate a series of sliced planes with a spacing of 1 mm in the z-axis direction, as Figure 4 shown in b.

[0100] (4) Taking the first layer of slice plane as an example (z = 1mm), traverse all triangular facets. When the minimum z - coordinate in a certain triangular facet is less than 1mm and the maximum z - coordinate is greater than 1mm, it indicates that this triangular facet intersects with this layer of slice, and it is put into the triangular list matrix of this layer. By cycling through each layer of slice plane in this way, the triangular list matrix of each layer of slice is obtained.

[0101] (5) For a single - layer slice plane, successively take out the triangular facets that intersect with it obtained in step (4) and calculate the intersection points of the slice plane and the triangular facets. The method for finding the intersection points is as follows: Assume the slice plane is z = c (c is a constant), and the three vertex coordinates of a triangular facet with intersection points are V1(x1, y1, z1), V2(x2, y2, z2), V3(x3, y3, z3), and the intersection coordinates are P1(x4, y4, z4), P2(x5, y5, z5). Then x4 = x1 + t * (x2 - x1), y4 = y1 + t * (y2 - y1), z4 = c, where t = (c - z1) / (z2 - z1). The intersection points obtained at this time include the external contour points and internal contour points of the part of this layer.

[0102] (6) Repeat step (5) in a loop to obtain the intersection points of each layer of slice plane and the triangular facets, that is, the external contour points of the hollow cylinder, and generate a contour point matrix.

[0103] (7) Imagine a printing platform of 20 x 20mm 2 That is, the size of each slice plane is also 20 x 20mm. 2 .

[0104] (8) For the convenience of observation and to reduce the operation time, assume that the filling line spacing (laser scanning spacing) is 1mm. If the filling lines of the first - layer slice plane are parallel to the x - axis, then the filling lines of the second - layer slice plane form an angle of 67° with the x - axis. Taking the second layer as an example, generate a series of filling lines that form an angle of 67° with the x - axis and have a spacing of 1mm to fill the entire slice plane imagined in step (7). According to the contour point matrix obtained in step (6), find the contour points on the second - layer slice plane, and filter the filling lines that intersect with the part contour according to the contour points and retain them.

[0105] (9) Calculate the intersection points of the filling lines and the hollow cylinder contour. Since there are both external and internal contours in the hollow cylinder, the number of intersection points of the filling lines and the contour is either two or four. When there are four intersection points, the order of the intersection points needs to be arranged to prevent the hollow inner circle from being filled. The laser scanning path on the second - layer slice plane is as Figure 4 shown in c.

[0106] (10) Repeat steps (8) and (9) to obtain the intersection matrix of the filling lines and the hollow cylinder contour on all slice planes. The overall filling effect of the part is as follows: Figure 4 As shown in d.

[0107] (11) According to the actual manufacturing process, the processing time, laser scanning path and laser state are written into the same matrix and then output as an inp file by MATLAB.

[0108] (12) Import the inp file into the AM Modeler plug-in of the finite element software ABAQUS to simulate the entire process of laser selective melting to manufacture hollow cylindrical parts.

[0109] Corresponding to the embodiment of the above method, the embodiment of the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the steps of the above method are implemented when the processor executes the program.

[0110] Furthermore, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method when the program is executed by a processor.

[0111] The following is an introduction to a system for finite element simulation of additive manufacturing laser scanning paths disclosed in an embodiment of the present invention. The system for finite element simulation of additive manufacturing laser scanning paths described below and the method for finite element simulation of additive manufacturing laser scanning paths described above can refer to each other.

[0112] The present invention also provides a system for simulating an additive manufacturing laser scanning path based on finite element method, comprising:

[0113] A data reading module is used to read the three-dimensional coordinates of each vertex of each triangular face and the normal vector of the triangular face in the part model file to be printed by using MATLAB;

[0114] The part slicing module is used to generate multiple equally spaced and infinitely large slicing planes. According to the height position of the slices and the three-dimensional coordinates of each vertex of the triangular facets, all the triangular facets intersecting with the slicing planes are screened out; all the intersection points of the slicing planes and the triangular facets are solved according to the spatial coordinate system, and the overlapping intersection points are eliminated to obtain the contour points of the part on each layer of the slicing plane and generate the intersection matrix;

[0115] The part filling module is used to imagine a printing platform that can accommodate the entire part according to the size of the part to be printed, and reduce the imaginary infinitely large slicing plane to the size of the printing platform; generate multiple equally spaced filling lines in the reduced slicing plane, and screen out the filling lines that intersect with the part contour according to the intersection point matrix; calculate the intersection points of the screened filling lines and the part contour to obtain the intersection point matrix of the filling lines and the part contour on all slicing planes, and the connection between the intersection points is the laser scanning path.

[0116] The laser scanning simulation module is used to write the laser scanning path, processing time, and laser state into the same matrix, and output it as an inp file using MATLAB; import the inp file into the AM Modeler plug-in of the finite element software ABAQUS to simulate the entire process of manufacturing parts by selective laser melting.

[0117] In an embodiment of the present invention, in the part filling module, the method for screening out the filling lines that intersect with the part contour according to the intersection point matrix includes:

[0118] Obtain the contour points of the part on a slicing plane according to the intersection point matrix, connect the contour points in sequence to obtain the edges of the part contour on this slicing plane, and judge whether the two vertices on the edge of the part contour are on the same side of the filling line. If so, the filling line does not intersect with the part contour; if not, the filling line intersects with the part contour.

[0119] The system for simulating the laser scanning path of additive manufacturing based on finite element in this embodiment is used to implement the foregoing method for simulating the laser scanning path of additive manufacturing based on finite element. Therefore, the specific implementation of this system can be seen in the embodiment part of the method for simulating the laser scanning path of additive manufacturing based on finite element in the foregoing text. Therefore, its specific implementation can refer to the descriptions of the corresponding individual part embodiments and will not be elaborated here.

[0120] In addition, since the system for simulating the laser scanning path of additive manufacturing based on finite element in this embodiment is used to implement the foregoing method for simulating the laser scanning path of additive manufacturing based on finite element, its function corresponds to the function of the above method and will not be elaborated here.

[0121] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0122] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to produce a machine, such that the instructions executed by the processors of the computer or other programmable data processing devices generate means for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or means for implementing the functions specified in multiple blocks.

[0123] These computer program instructions can 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, such that the instructions stored in the computer-readable memory produce a manufactured article including instruction means that implement the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or means for implementing the functions specified in multiple blocks.

[0124] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or means for implementing the functions specified in multiple blocks.

[0125] Obviously, the above embodiments are merely examples for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to exhaustively list all implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for simulating the laser scanning path of additive manufacturing based on finite element, characterized in that: It includes the following steps: S1: Use MATLAB to read the three-dimensional coordinates of each vertex of each triangular facet in the part model file to be printed and the normal vector of the triangular facet; S2: Imagine multiple equally spaced and infinitely large slicing planes. According to the height position of the slice and the three-dimensional coordinates of each vertex of the triangular facet, screen out all the triangular facets that intersect the slicing plane; S3: Solve all the intersection points of the slicing plane and the triangular facet according to the space coordinate system, eliminate the overlapping intersection points, and obtain the contour points of the part on a single-layer slicing plane; S4: Repeat step S3 to obtain the contour points of the part on each slicing plane and generate a contour point matrix; S5: Imagine a printing platform that can accommodate the entire part according to the size of the part to be printed, and reduce the infinitely large slicing plane imagined in step S1 to the size of the printing platform; S6: Generate multiple equally spaced filling lines in the reduced slicing plane, and screen out the filling lines that intersect the part contour according to the contour point matrix obtained in step S4; S7: Calculate the intersection points of the screened filling lines and the part contour to obtain an intersection point matrix of the filling lines and the part contour on a slicing plane; S8: Repeat steps S6 and S7 to obtain the intersection point matrix of the filling lines and the part contour on all slicing planes. The connection between the intersection points is the laser scanning path; S9: Write the laser scanning path, processing time, and laser status into the same matrix, and use MATLAB to output it as an inp file; S10: Import the inp file into finite element software to simulate the entire process of manufacturing the part by selective laser melting.

2. The method for simulating the laser scanning path of additive manufacturing based on finite element according to claim 1, characterized in that: Before using MATLAB to read the part model to be printed, save the part model as an stl format file.

3. The method for simulating the laser scanning path of additive manufacturing based on finite element according to claim 1, characterized in that: In step S2, the method of imagining and generating multiple equally spaced and infinitely large slicing planes includes: Generate multiple equally spaced and infinitely large slicing planes in the z-axis direction.

4. The method for simulating the laser scanning path of additive manufacturing based on finite element according to claim 1 or 3, characterized in that: In step S2, the method of screening out all the triangular facets that intersect the slicing plane according to the height position of the slice and the three-dimensional coordinates of each vertex of the triangular facet includes: Create a triangle list for each slicing plane; On each slicing plane, screen out all the triangular facets that intersect the slicing plane, and record all the data of the screened triangular facets in the triangle list of the slicing plane.

5. The method for simulating the laser scanning path of additive manufacturing based on finite element according to claim 4, characterized in that: In the method of screening out all the triangular facets that intersect a slicing plane on each slicing plane, it includes: When the z coordinate of a vertex of a triangular facet is lower than the z coordinate of a slicing plane, and the z coordinate of another vertex of the triangular facet is higher than the z coordinate of the slicing plane, then the triangular facet intersects the slicing plane.

6. The method for simulating the laser scanning path of additive manufacturing based on finite element according to claim 5, characterized in that: In step S6, the method of screening out the filling lines that intersect the part contour according to the intersection point matrix includes: Obtain the contour points of the part on a slicing plane according to the contour point matrix, connect the contour points in sequence to obtain the edges of the part contour on the slicing plane, and judge whether the two vertices on the edge of the part contour are on the same side of the filling line. If so, the filling line does not intersect the part contour; if not, the filling line intersects the part contour.

7. A system for simulating the laser scanning path of additive manufacturing based on finite element, characterized in that: It includes: A data reading module is used to read the three-dimensional coordinates of each vertex of each triangular face and the normal vector of the triangular face in the part model file to be printed by using MATLAB; The part slicing module is used to generate multiple equally spaced and infinitely large slicing planes. According to the height position of the slices and the three-dimensional coordinates of each vertex of the triangular facets, all the triangular facets intersecting with the slicing planes are screened out; all the intersection points of the slicing planes and the triangular facets are solved according to the spatial coordinate system, and the overlapping intersection points are eliminated to obtain the contour points of the part on each layer of the slicing plane and generate a contour point matrix; A part filling module is used to imagine a printing platform that can accommodate the entire part according to the size of the part to be printed, and reduce the imaginary infinite slicing plane to the size of the printing platform; Generate multiple equally spaced fill lines in the reduced slice plane, and select the fill lines that intersect the part contour according to the contour point matrix; Calculate the intersection points of the selected fill lines and the part contours to obtain the intersection matrix of the fill lines and the part contours on all slice planes. The lines between the intersection points are the laser scanning paths. The laser scanning simulation module is used to write the laser scanning path, processing time and laser state into the same matrix and output them as inp files using MATLAB; the inp files are imported into the finite element software to simulate the entire process of laser selective melting to manufacture parts.

8. The system for laser scanning path of additive manufacturing based on finite element simulation according to claim 7, wherein: In the part filling module, a method for obtaining a filling line intersecting with a part contour by screening according to a contour point matrix includes: According to the intersection matrix, the contour points of the part on a slice plane are obtained, and the contour points are connected in sequence to obtain the edge of the part contour on the slice plane. It is determined whether the two vertices on the edge of the part contour are on the same side of the fill line. If so, the fill line does not intersect with the part contour. If not, the fill line intersects with the part contour.

9. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein: When the processor executes the program, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium, on which a computer program is stored, wherein: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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