Rapid printing method based on self-adaptive honeycomb partition

Abstract

The invention relates to the technical field of metal laser 3D printing manufacturing, in particular to a rapid printing method based on self-adaptive honeycomb zoning, which comprises the following steps: analyzing a printed part finished product through stress simulation software to obtain a stress distribution diagram of a to-be-printed area; honeycomb partitions with the same honeycomb unit size are constructed in the same printing coordinate system to cover the to-be-printed area; based on the stress distribution diagram of the to-be-printed area, honeycomb unit size self-adaptive adjustment is carried out on honeycomb subareas with the same honeycomb unit size of the printing area; and obtaining a printed piece based on the self-adaptive honeycomb partition as a printing track. According to the method, the sizes of the honeycomb units of the honeycomb subareas are adaptively adjusted, so that the stress of a large stress area is reduced, and the stress of each area of a workpiece is relatively average; meanwhile, the number of honeycomb partitions in a low-stress area is reduced, and the defect that the printing speed is low in traditional chessboard scanning or honeycomb scanning is overcome.

Description

Technical Field

[0001] The invention relates to the technical field of metal laser 3D printing manufacturing, and in particular to a rapid printing method based on adaptive honeycomb partitioning. Background Art

[0002] Metal laser 3D printing uses a method of adding metal powder layer by layer. For each layer to be printed, the metal powder is evenly spread on the printing platform. The laser melts the powder point by point along a preset path, so that the powder in adjacent paths is melted and sintered into shape. After completing a single layer, the next layer is printed until the entire metal part is printed.

[0003] In one aspect of the prior art, the laser scanning path uses a strip scanning method, and prints line by line in a parallel strip manner on each layer. The continuous scanning partition is large, which affects the distribution of stress, and the accumulated residual stress after cooling is large, such as Figure 1a-1b In another aspect of the prior art, the laser scanning path can use a chessboard scanning or honeycomb partition scanning method to divide the printing area into several small blocks similar to a chessboard or honeycomb layout, and alternately print adjacent small blocks. The chessboard scanning method is as follows: Figure 2a-2b As shown; however, chessboard scanning or honeycomb layout scanning slows down the laser scanning speed and increases the printing time due to the addition of jump paths; in addition, the prior art uses chessboard scanning or honeycomb partition scanning, and its scanning basic unit / partition unit is often fixed. The prior art honeycomb partition scanning method prints the product such as Figure 3 As shown, there is a large difference in stress between different regions. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a fast printing method based on adaptive honeycomb partitioning to solve at least one of the problems in the prior art, such as large residual stress, slow printing speed, and uneven stress in the printing area.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] The present invention provides a fast printing method based on adaptive honeycomb partitioning, comprising:

[0007] Analyze the printed product through stress simulation software to obtain the stress distribution diagram of the area to be printed;

[0008] Construct honeycomb partitions with the same honeycomb unit size in the same printing coordinate system to cover the area to be printed;

[0009] Based on the stress distribution map of the area to be printed, the honeycomb cell sizes of the honeycomb partitions with the same honeycomb cell size in the printing area are adaptively adjusted to obtain adaptive honeycomb partitions with more balanced stress distribution;

[0010] A printed product is obtained based on the adaptive honeycomb partitions as a printing trajectory.

[0011] Preferably, obtaining an adaptive honeycomb partition with a more balanced stress distribution includes: adjusting the vertex positions of the honeycomb partition according to the stress distribution diagram of the area to be printed, so that the elastic potential energy of the spring system formed by the vertices in any two honeycomb partitions is substantially the same.

[0012] Preferably, obtaining an adaptive honeycomb partition with a more balanced stress distribution includes:

[0013] S301: constructing a double-mass spring system by grouping adjacent vertices in the honeycomb partition into two groups, and calculating the elastic potential energy of the spring system;

[0014] S302: Calculate the resultant force of the three adjacent vertices of the vertex of the honeycomb partition, and obtain the resultant force of the vertices of all honeycomb partitions

[0015] S303: Displace the vertices of all honeycomb partitions in the direction of the resultant force they are subjected to

[0016]

[0017] S304: Yes Numerical judgment of:

[0018] When the displacement of all vertices of the honeycomb partition If the value of is less than e, the honeycomb partition completes the adaptive change, and the connection line of the honeycomb partition vertices can be used as a printing track;

[0019] When the displacement of all vertices of the honeycomb partition If the value of ≥ e, the cell partition has not completed the adaptive change, and S301-S303 are repeated until The value of is less than e.

[0020] Preferably, calculating the elastic potential energy of the spring system in S301 includes:

[0021] The energy density U of all spring systems is obtained from the stress distribution diagram at each position of the honeycomb partition side length;

[0022] The energy density U of all spring systems is integrated at each position of the honeycomb partition side to obtain the elastic potential energy of each spring system.

[0023] Preferably, calculating the elastic potential energy of the spring system in S301 includes:

[0024] S3011: Convert the stress distribution diagram into a two-dimensional plane coordinate system with the distance between the two end points of the spring system as a variable and the stress as a dependent variable;

[0025] S3012: Subdivide the line segment of the distance between the two end points of the spring system into multiple small segments, and the distance between each small segment is δ;

[0026] S3013: According to the center point of each small segment, find the stress of the point on the stress distribution diagram as the average stress σ of the small segment;

[0027] S3014: according to the calculation formula of energy density, based on the average stress σ, calculate and obtain the average value of the energy density U of the small segment;

[0028] S3015: Multiply the average value of the energy density U of the small segment by the length δ of the small segment to obtain the strain energy E of the small segment 1 ;

[0029] S3016: Based on the above steps, the strain energies of all small segments are obtained, and the elastic potential energy of the spring system is obtained by summing up the strain energies of all small segments.

[0030] Preferably, the calculation formula of energy density in S3014 satisfies:

[0031] Where E is the Young's modulus of the material.

[0032] Preferably, S3012 may be 0.0005 to 0.002 of the distance between the two end points of the spring system.

[0033] Preferably, S303 includes: based on the vertex coordinates of the honeycomb partitions, processing the vertices of all honeycomb partitions in sequence from one side to the other side of the area to be printed.

[0034] Preferably, the vertex coordinates based on the honeycomb partitions include: comparing and screening the vertex coordinates, horizontal coordinates and vertical coordinates of all honeycomb partitions, and further determining the processing order of the vertex coordinates of all honeycomb partitions according to the sorting result.

[0035] Preferably, the printed product is prepared by printing by the following method, including: the scanning track adopts honeycomb partitions with fixed honeycomb unit sizes.

[0036] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0037] (1) The present invention adaptively adjusts the size of honeycomb units in honeycomb partitions. On the one hand, for areas with relatively large stress in the stress distribution diagram, stress reduction in large stress areas is achieved, thereby avoiding the problem of large cold-accumulated residual stress in the prior art, which is prone to cause local cracking. On the other hand, in addition to reducing stress in large stress areas, the original honeycomb partition size is appropriately increased and the number of honeycomb partitions is reduced for areas with relatively small stress, so that stress in various areas of the workpiece is relatively even. In addition, for areas with relatively small stress, the number of honeycomb partitions is not increased, and thus the jump path is not increased, thereby ensuring a faster laser scanning speed and printing speed, and overcoming the defect of slow printing speed in traditional chessboard scanning or honeycomb scanning. Compared with traditional chessboard scanning or honeycomb partition scanning with fixed honeycomb unit size, the present invention improves printing efficiency while reducing residual stress differences.

[0038] (2) The present invention constructs a double-mass spring system by grouping adjacent vertices in the vertices of the honeycomb partitions in pairs, calculates the elastic potential energy of all spring systems and the resultant force on the vertices of all honeycomb partitions, displaces the vertices of the core honeycomb partition in the direction of the resultant force, and calculates the elastic potential energy of all spring systems after each displacement. This realizes adaptive adjustment of the vertices of the honeycomb partitions and obtains a honeycomb partitioning scheme with the lowest stress and stress energy (elastic potential energy). Compared with the partitioning scheme of the prior art in which the size of the honeycomb unit remains unchanged, this method overcomes the defect that the residual stress in some areas is large and easily causes local cracks, and also makes the stress in each area of ​​the product more uniform.

[0039] (3) The present invention constructs an elastic potential energy model with the vertices of the honeycomb partition as the center of mass, converts the stress energy of the honeycomb partition in the printing area into the elastic potential energy of the spring system where the vertices of the honeycomb partition are located for analysis and dimensionality reduction, which greatly simplifies the calculation process and improves the calculation rate.

[0040] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the embodiments of the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0042] Figure 1a A schematic diagram of a scanning trajectory of a strip scanning in the prior art;

[0043] Figure 1bIt is a strip scanning workpiece simulation analysis in the prior art;

[0044] Figure 2a A schematic diagram of a scanning trajectory of a chessboard scan in the prior art;

[0045] Figure 2b Simulation analysis of chessboard scanning parts in the prior art;

[0046] Figure 3 Simulation analysis of honeycomb partition printing parts with fixed honeycomb unit size in the prior art;

[0047] Figure 4 It is the elastic vibration model of the honeycomb partition endpoint in the embodiment of the present invention;

[0048] Figure 5 A schematic diagram of calculating the stress energy or elastic potential energy of a spring system according to the present invention;

[0049] Figure 6 Printed products prepared for embodiments of the present invention or subjected to stress analysis;

[0050] Figure 7 This is a schematic diagram of the combined force of the endpoints of the cellular partitions according to the first embodiment of the present invention;

[0051] Figure 8 This is a schematic diagram of the displacement of the endpoints of the honeycomb partitions in the direction of the resultant force according to Embodiment 1 of the present invention;

[0052] Fig. 9 This is a simulation analysis of a printed product prepared after adaptive honeycomb partitioning according to Example 1 of the present invention.

[0053] Reference numerals:

[0054] Two-mass-spring system 01; Vertex 011 of honeycomb partition; Honeycomb partition 02. DETAILED DESCRIPTION

[0055] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0056] The applicant has found that the residual stress in different locations of metal laser 3D printing is not the same. Depending on the shape of the printed part, the stress in different areas varies greatly, and the edge stress is generally greater than the center area. Fixed-size partitions will cause the distribution of residual stress in different locations of the printed part to vary greatly, making it difficult to eliminate the residual stress in the subsequent annealing process to eliminate the stress. When the uneven stress distribution is serious, the area with particularly large local stress may even warp and crack.

[0057] Although stress can be reduced by shrinking the partitions uniformly, thereby reducing the difference in stress distribution, the printing efficiency will be significantly reduced: because the laser needs to jump between different partitions, the more partitions there are, the lower the printing efficiency will be due to frequent laser jumps.

[0058] Therefore, in the prior art, metal laser 3D printing, whether chessboard scanning or strip scanning, uses a partitioning method with a fixed scanning unit size. Under this partitioning method, the contradiction between "reducing residual stress differences" and "improving printing efficiency" is difficult to reconcile.

[0059] In one aspect, the present invention discloses a fast printing method based on adaptive honeycomb partitioning, comprising:

[0060] S1: Analyze the printed product through stress simulation software to obtain the stress distribution diagram of the area to be printed;

[0061] S2: construct honeycomb partitions with the same honeycomb unit size in the same printing coordinate system to cover the area to be printed;

[0062] S3: Based on the stress distribution map of the area to be printed, the honeycomb partitions with the same honeycomb unit size in the printing area are adaptively adjusted to obtain adaptive honeycomb partitions with more balanced stress distribution;

[0063] S4: Obtain a printed part based on the adaptive honeycomb partition obtained in S3 as a printing trajectory.

[0064] During implementation, on the one hand, for areas with higher stress in the stress distribution diagram, the original honeycomb partition size is reduced and the number of honeycomb partitions is increased to reduce the stress in the corresponding area; on the other hand, for areas with lower stress, the original honeycomb partition size is appropriately increased and the number of honeycomb partitions is reduced to make the stress in each area of ​​the workpiece more evenly distributed; in addition, an adaptive adjustment method based on the stress distribution diagram of the printing area is adopted to realize feedback adjustment from output to input, which helps to obtain the optimal stress output result.

[0065] Compared with the prior art, the present invention adaptively adjusts the size of honeycomb units in honeycomb partitions. On the one hand, for the area with large stress in the stress distribution diagram, stress reduction in the large stress area is achieved, thereby avoiding the problem of large cold-accumulated residual stress in the prior art, which is easy to cause local cracking; on the other hand, in addition to reducing the stress in the large stress area, for the area with small stress, the original honeycomb partition size is appropriately increased and the number of honeycomb partitions is reduced, so that the stress in each area of ​​the workpiece is more even; in addition, for the area with small stress, the number of honeycomb partitions is not increased, and thus the jump path is not increased, thereby ensuring a faster laser scanning speed and printing speed, and overcoming the defect of slow printing speed in traditional chessboard scanning or honeycomb scanning; compared with traditional chessboard scanning or honeycomb partition scanning with fixed honeycomb unit size, the present invention improves printing efficiency while reducing the difference in residual stress.

[0066] Specifically, the stress simulation software in S1 can be any one of ANSYS, Amphyon, and Netfabb.

[0067] During implementation, the shape and material of the area to be printed can be input to output the stress distribution map of the area to be printed; since 3D printing is performed by printing and stacking layers with the surface as the printing unit, it is only necessary to determine the printing trajectory of one surface (printing area).

[0068] As an example, Figure 6 For the part to be printed shown, it is only necessary to determine the printing trajectory of the AA section.

[0069] It should be noted that the present invention aims at the problems of large local stress and uneven stress in different regions in printing in the prior art. Therefore, the printed parts prepared by the prior art can be used as input of the stress simulation software in S1 to obtain the stress distribution map of the area to be printed, and use it as the basis for adaptive adjustment of honeycomb partitions.

[0070] Specifically, the method for obtaining the printed product may be honeycomb partitioning with a fixed honeycomb unit size, strip scanning partitioning, or chessboard scanning partitioning.

[0071] Specifically, the raw material of the printed part can be titanium alloy, aluminum alloy, high-temperature alloy or stainless steel.

[0072] Specifically, the side length of the initial honeycomb partition constructed by S2 is 10 mm to 20 mm.

[0073] It should be noted that sharing a coordinate system for the honeycomb partition and the stress distribution diagram is helpful for subsequent honeycomb adaptive adjustment and calculation; the honeycomb sizes matched with different source materials are different, and the scanning power change will also affect the honeycomb size. The present invention sets the initial honeycomb partition side length to 10mm to 20mm, which has good applicability for different types of alloys.

[0074] Specifically, in S3, the honeycomb unit sizes of the honeycomb partitions with the same honeycomb unit size in the printing area are adaptively adjusted, including: adjusting the vertex positions of the honeycomb partitions according to the stress distribution diagram of the area to be printed, so that the elastic potential energy of the spring system composed of the vertices in any two honeycomb partitions is basically the same.

[0075] It should be noted that if Figure 3 As shown, the stress distribution diagram of the area to be printed is the stress distribution diagram at different positions. When the stress is not 0, it is considered that stress energy exists.

[0076] During implementation, the present invention constructs an elastic potential energy model with the vertices of the honeycomb partitions as the center of mass, converts the stress energy of the honeycomb partitions in the printing area into the elastic potential energy of the spring system where the vertices of the honeycomb partitions are located for analysis and dimensionality reduction, which greatly simplifies the calculation process and improves the calculation rate.

[0077] Specifically, S3 includes:

[0078] S301: constructing a double-mass spring system by grouping adjacent vertices in the honeycomb partition into two groups, and calculating the elastic potential energy of the spring system;

[0079] S302: Calculate the resultant force of the three adjacent vertices of the vertex of the honeycomb partition, and obtain the resultant force of the vertices of all honeycomb partitions

[0080] S303: Displace the vertices of all honeycomb partitions in the direction of the resultant force they are subjected to

[0081] S304: Yes Numerical judgment of:

[0082] When the displacement of all vertices of the honeycomb partition If the value of is less than e, the honeycomb partition completes the adaptive change, and the connection line of the honeycomb partition vertices can be used as a printing track;

[0083] When the displacement of all vertices of the honeycomb partition If the value of ≥ e, the cell partition has not completed the adaptive change, and S301-S303 are repeated until The value of is less than e or the number of iterations reaches the upper limit.

[0084] It should be noted that the upper limit of the number of iterations is set to avoid The value of is to satisfy <e infinite iterations wasting time and material costs; when the upper limit of the number of iterations is reached, If the value ≥ e, it means that the e value is set improperly and exceeds the system capability.

[0085] Specifically, k satisfies: k and the resultant force of each stress The product of the maximum values ​​of takes 0.2‰~0.5‰ of the side length of the honeycomb partition. e takes 0.05‰~0.2‰ of the side length of the honeycomb partition.

[0086] Specifically, Figure 4 As shown, S301 constructs a dual-mass spring system including: two elastically connected vertices of honeycomb partitions; the vertex of each honeycomb partition and the vertices of three adjacent honeycomb partitions form a spring oscillator model, and the vertex of each honeycomb partition is simultaneously subjected to the tension / pressure of the vertices of the three adjacent honeycomb partitions. The vertex of the honeycomb partition and the three adjacent honeycomb partitions form three spring systems, and the tension / pressure in the spring system is stored in the form of elastic potential energy.

[0087] It should be noted that the vertex of the honeycomb partition calculated in S302-S303 is subject to the combined force of its three adjacent vertices. Displace the vertices of all honeycomb partitions in the direction of the resultant force they receive Because in the joint efforts displacement in the direction, so that the resultant force Work is done, thereby reducing the total stress and total elastic potential energy of the three spring systems with the vertex of a certain honeycomb partition as the core; thus, after each iteration and the adjustment of the vertex position of the honeycomb partition, the total stress and total elastic potential energy of the honeycomb partition are reduced; at the same time, due to the displacement of the area with large stress A larger value makes the vertex position of the honeycomb partition in the area with high stress more adjusted, which helps to increase the iteration speed, make the stress difference in each area disappear quickly, and achieve stress balance in each area; at the same time, due to the resultant force on the vertex of the vector parameter honeycomb partition With the introduction of the above method, the stress in various directions can be processed simultaneously, including tension, pressure, outward tension, etc.

[0088] Compared with the prior art, the present invention constructs a double-mass spring system by grouping adjacent vertices in the vertices of the honeycomb partitions in pairs, calculates the elastic potential energy of all spring systems and the resultant force on the vertices of all honeycomb partitions, displaces the vertices of the core honeycomb partitions in the direction of the resultant force, and calculates the elastic potential energy of all spring systems after each displacement, thereby realizing adaptive adjustment of the vertices of the honeycomb partitions and obtaining a honeycomb partition scheme with the lowest stress and stress energy (elastic potential energy). Compared with the partition scheme of the prior art in which the size of the honeycomb unit remains unchanged, the present invention overcomes the defect that the residual stress in some areas is large and easily causes local cracks, and also makes the stress in each area of ​​the product more uniform.

[0089] Specifically, calculating the elastic potential energy of the spring system in S301 includes:

[0090] The energy density U of all spring systems is obtained from the stress distribution diagram at each position of the honeycomb partition side length;

[0091] The energy density U of all spring systems is integrated at each position of the honeycomb partition side to obtain the elastic potential energy of each spring system.

[0092] Specifically, calculating the elastic potential energy of the spring system in S301 includes:

[0093] S3011: convert the stress distribution diagram into a two-dimensional plane coordinate system with the honeycomb partition side length (the distance between the two end points of the spring system) as a variable and stress as a dependent variable;

[0094] S3012: Subdivide the line segment of the distance between the two end points of the spring system into multiple small segments, and the distance between each small segment is δ;

[0095] S3013: According to the center point of each small segment, find the stress of the point on the stress distribution diagram as the average stress σ of the small segment;

[0096] S3014: according to the calculation formula of energy density, based on the average stress σ, calculate and obtain the average value of the energy density U of the small segment;

[0097] S3015: Multiply the average value of the energy density U of the small segment by the length δ of the small segment to obtain the strain energy E of the small segment 1 ;

[0098] S3016: Based on the above steps, the strain energies of all small segments are obtained, and the elastic potential energy of the spring system is obtained by summing up the strain energies of all small segments.

[0099] Specifically, regarding the coordinate system transformation in S3011, Figure 5 For example: Figure 5 The left side provides a stress distribution diagram of stress in the plane coordinate system, and the color depth indicates the stress magnitude; Figure 5 The right side provides a stress distribution diagram of a two-dimensional plane coordinate system in the left enlarged area, with the side length of the honeycomb partition (the distance between the two end points of the spring system) as a variable and stress as a dependent variable; Figure 5 The right side can be Figure 5 The stress distribution diagram on the left is obtained from the source data.

[0100] Specifically, in order to facilitate calculation and take into account accuracy, δ in S3012 can be 0.0005 to 0.002 of the distance between the two end points of the spring system.

[0101] Specifically, the calculation formula of energy density in S3014 satisfies:

[0102] Where E is the Young's modulus of the material.

[0103] Preferably, in S303, the vertices of all honeycomb partitions are displaced in the direction of the resultant force to which they are subjected. The method comprises: based on the vertex coordinates of the honeycomb partitions, processing the vertices of all honeycomb partitions in sequence from one side to the other side of the area to be printed.

[0104] Specifically, the vertex coordinates, horizontal coordinates and vertical coordinates of all honeycomb partitions are compared and screened, and the processing order of the vertex coordinates of all honeycomb partitions is further determined according to the sorting result.

[0105] As an example, set the rules to process from the left side of the area to be printed to the right side in sequence:

[0106] S3031: compare the horizontal coordinates of the vertices of all honeycomb partitions and sort them from small to large;

[0107] S3032: Sort the horizontal coordinates of the vertices of all the honeycomb partitions as the processing order of the vertices of all the honeycomb partitions.

[0108] It should be noted that the first iterative adjustment of the vertex position of the honeycomb partition in S3 causes a large change, and the change will inevitably affect the vertices of adjacent honeycomb partitions. Therefore, it is particularly important to determine the processing order of the honeycomb partition vertices; according to the above S3031~S3032, the processing order of the vertices of the honeycomb partitions is determined, which can reduce the impact of the vertex position change of the honeycomb partition on the vertices of the adjacent honeycomb partitions to a certain extent.

[0109] In order to better illustrate the present invention, the following embodiments are provided:

[0110] Example 1

[0111] This embodiment discloses a fast printing method based on adaptive cellular partitioning, including:

[0112] S1: Through ANSYS stress simulation software, Figure 6 The AA section stress analysis of the printed part is obtained Figure 3 Stress distribution diagram of the area to be printed; wherein the workpiece to be printed is a rectangular base with a rectangular boss structure fixedly connected to the center, and the boss width a 1 =82mm, boss height h 1 =86mm; Distance a between the boss and the base 2 =36mm; base height h 2 =26mm; printing material is TA15 titanium alloy.

[0113] Figure 6 The middle product is a honeycomb partition printed product with the same honeycomb unit size in the prior art, the side length of the honeycomb partition is 10 mm, the laser scanning rate is 1000 mm / s, and the laser power is 300 w, which is the same as S4 in this embodiment;

[0114] S2: Construct honeycomb partitions with the same honeycomb unit size in the same printing coordinate system to cover the area to be printed; the side length of the initial honeycomb partition constructed by S2 is 10 mm.

[0115] S3: Based on the stress distribution map of the area to be printed, the honeycomb partitions with the same honeycomb unit size in the printing area are adaptively adjusted to obtain adaptive honeycomb partitions with more balanced stress distribution;

[0116] S301: constructing a double-mass spring system by grouping adjacent vertices in the honeycomb partition into two groups, and calculating the elastic potential energy of the spring system;

[0117] like Figure 4 As shown, S301 constructs a dual-mass spring system 01 including: two elastically connected vertices 011 of honeycomb partitions, and at the same time, the vertex 011 of each honeycomb partition and the vertices 011 of the three adjacent honeycomb partitions form a more complex spring system, and the vertex of each honeycomb partition is simultaneously subjected to the tension / pressure of the vertices of the three adjacent honeycomb partitions. The vertex of the honeycomb partition and the three adjacent honeycomb partitions form three spring systems, and the tension / pressure in the spring system is stored in the form of elastic potential energy.

[0118] S3011: convert the stress distribution diagram into a two-dimensional plane coordinate system with the honeycomb partition side length (the distance between the two end points of the spring system) as a variable and stress as a dependent variable;

[0119] S3012: The line segment of the distance between the two end points of the spring system is subdivided into multiple small segments, and the distance of each small segment is δ; δ is 0.001 of the distance between the two end points of the spring system.

[0120] S3013: According to the center point of each small segment, find the stress of the point on the stress distribution diagram as the average stress σ of the small segment;

[0121] S3014: According to the calculation formula of energy density, the average value of the energy density U of the small segment is calculated based on the average stress σ; the calculation formula of energy density satisfies:

[0122] Wherein, E is the Young's modulus of the material, which is 110 GPa.

[0123] S3015: Multiply the average value of the energy density U of the small segment by the length δ of the small segment to obtain the strain energy E of the small segment 1 ;

[0124] S3016: Based on the above steps, the strain energies of all small segments are obtained, and the elastic potential energy of the spring system is obtained by summing up the strain energies of all small segments.

[0125] S302: Calculate the resultant force of the three adjacent vertices of the vertex of the honeycomb partition, and obtain the resultant force of the vertices of all honeycomb partitions

[0126] like Figure 7 As shown, in Figure 7 The resultant force on the vertices of a honeycomb partition is given in Three examples: In example A, the resultant force on the vertices of the honeycomb partition is As shown by the red arrow, the vertices of the honeycomb partition and the vertices of the adjacent honeycomb partition are connected in the direction of the side length of the honeycomb partition; the resultant force on the vertices of the honeycomb partition in area B of the example is As shown by the red arrows, the resultant force on the two vertices of the honeycomb partition in area C of the example As indicated by the red arrow.

[0127] S303: Displace the vertices of all honeycomb partitions in the direction of the resultant force they are subjected to

[0128]

[0129] S304: Yes Numerical judgment of:

[0130] When the displacement of all vertices of the honeycomb partition If the value of is less than e, the honeycomb partition completes the adaptive change, and the connection line of the honeycomb partition vertices can be used as a printing track;

[0131] When the displacement of all vertices of the honeycomb partition If the value of ≥ e, the cell partition has not completed the adaptive change, and S301-S303 are repeated until The value is less than e or the number of iterations reaches the upper limit of 1000. e is 0.1‰ of the side length of the honeycomb partition; k satisfies: k and the resultant force of each stress The product of the maximum values ​​is taken as 0.5‰ of the side length of the honeycomb partition.

[0132] Set the rules to process from the left side of the area to be printed to the right side in sequence:

[0133] S3031: compare the horizontal coordinates of the vertices of all honeycomb partitions and sort them from small to large;

[0134] S3032: Sort the horizontal coordinates of the vertices of all the honeycomb partitions as the processing order of the vertices of all the honeycomb partitions.

[0135] like Figure 8 As shown, in Figure 8 The resultant force on the vertices of a honeycomb partition is given in Three examples of directional displacement: In example A, the resultant force on the vertices of the honeycomb partition in area A is As shown by the red arrow, the green position is the position of the honeycomb partition vertex after the first iterative displacement; the resultant force on the vertex of the honeycomb partition in area B of the example As shown by the red arrow, the green position is the position of the honeycomb partition vertex after the first iterative displacement; the resultant force on the two vertices of the honeycomb partition in area C of the example As shown by the red arrow, the green position is the position of the honeycomb partition vertex after the first iterative displacement.

[0136] S4: Based on the adaptive honeycomb partition obtained in S3 as the printing trajectory, the printed product is obtained. Fig. 9 As shown, the adaptive cell partition 02 is irregularly distributed and is completely different from the initial state of the S2 cell partition; and Figure 3 Compared with the parts prepared by honeycomb partitions with the same size of traditional honeycomb units, the stress in the large stress area is reduced, and the stress in each area is less than 20ksi, which avoids the problem of large cold accumulated residual stress in the prior art, which is easy to cause local cracking; in addition to reducing the stress in the large stress area, for the area with smaller stress, the original honeycomb partition size is appropriately increased, and the number of honeycomb partitions is reduced, so that the stress in each area of ​​the part is more average, and the stress unevenness between the areas is reduced; in addition, since the number of honeycomb partitions is not increased, the jump path is not increased, which ensures a faster laser scanning speed and printing speed, and overcomes the defect of slow printing speed in traditional chessboard scanning or honeycomb scanning; compared with traditional chessboard scanning or honeycomb partition scanning with fixed honeycomb unit size, the present invention improves printing efficiency while reducing the difference in residual stress.

[0137] Example 2

[0138] This embodiment discloses a fast printing method based on adaptive cellular partitioning, including:

[0139] S1: Through Netfabb stress simulation software, Figure 6 The stress distribution diagram of the to-be-printed area is obtained by stress analysis of the AA section of the to-be-printed part; wherein the to-be-printed part is a rectangular parallelepiped base with a rectangular boss structure fixedly connected to the center, and the boss width a 1 =82mm, boss height h 1 =86mm; Distance a between the boss and the base 2 =36mm; base height h 2 =26mm; printing material is AlSi10Mg aluminum alloy.

[0140] Figure 6The middle product is a honeycomb partition printed product with the same honeycomb unit size in the prior art, the side length of the honeycomb partition is 10 mm, the laser scanning rate is 800 mm / s, and the laser power is 400 w, which is the same as S4 in this embodiment;

[0141] S2: Construct honeycomb partitions with the same honeycomb unit size in the same printing coordinate system to cover the area to be printed; the side length of the initial honeycomb partition constructed by S2 is 10 mm.

[0142] S3: Based on the stress distribution map of the area to be printed, the honeycomb partitions with the same honeycomb unit size in the printing area are adaptively adjusted to obtain adaptive honeycomb partitions with more balanced stress distribution;

[0143] S301: constructing a double-mass spring system by grouping adjacent vertices in the honeycomb partition into two groups, and calculating the elastic potential energy of the spring system;

[0144] like Figure 4 As shown, S301 constructs a dual-mass spring system 01 including: two elastically connected vertices 011 of honeycomb partitions, and at the same time, the vertex 011 of each honeycomb partition and the vertices 011 of the three adjacent honeycomb partitions form a more complex spring system, and the vertex of each honeycomb partition is simultaneously subjected to the tension / pressure of the vertices of the three adjacent honeycomb partitions. The vertex of the honeycomb partition and the three adjacent honeycomb partitions form three spring systems, and the tension / pressure in the spring system is stored in the form of elastic potential energy.

[0145] S3011: convert the stress distribution diagram into a two-dimensional plane coordinate system with the honeycomb partition side length (the distance between the two end points of the spring system) as a variable and stress as a dependent variable;

[0146] S3012: The line segment of the distance between the two end points of the spring system is subdivided into multiple small segments, and the distance of each small segment is δ; δ is 0.001 of the distance between the two end points of the spring system.

[0147] S3013: According to the center point of each small segment, find the stress of the point on the stress distribution diagram as the average stress σ of the small segment;

[0148] S3014: According to the calculation formula of energy density, the average value of the energy density U of the small segment is calculated based on the average stress σ; the calculation formula of energy density satisfies:

[0149] Wherein, E is the Young's modulus of the material, which is 75 GPa.

[0150] S3015: Multiply the average value of the energy density U of the small segment by the length δ of the small segment to obtain the strain energy E of the small segment 1 ;

[0151] S3016: Based on the above steps, the strain energies of all small segments are obtained, and the elastic potential energy of the spring system is obtained by summing up the strain energies of all small segments.

[0152] S302: Calculate the resultant force of the three adjacent vertices of the vertex of the honeycomb partition, and obtain the resultant force of the vertices of all honeycomb partitions

[0153] S303: Displace the vertices of all honeycomb partitions in the direction of the resultant force they are subjected to

[0154]

[0155] S304: Yes Numerical judgment of:

[0156] When the displacement of all vertices of the honeycomb partition If the value of is less than e, the honeycomb partition completes the adaptive change, and the connection line of the honeycomb partition vertices can be used as a printing track;

[0157] When the displacement of all vertices of the honeycomb partition If the value of ≥ e, the cell partition has not completed the adaptive change, and S301-S303 are repeated until The value of is less than e or the number of iterations reaches the upper limit of 1000. e is 0.1‰ of the side length of the honeycomb partition.

[0158] Set the rules to process from the left side of the area to be printed to the right side in sequence:

[0159] S3031: compare the horizontal coordinates of the vertices of all honeycomb partitions and sort them from small to large;

[0160] S3032: Sort the horizontal coordinates of the vertices of all the honeycomb partitions as the processing order of the vertices of all the honeycomb partitions.

[0161] S4: The printed product is obtained based on the adaptive honeycomb partition obtained in S3 as the printing trajectory, and the adaptive honeycomb partition 02 is irregularly distributed and is completely different from the initial state of the honeycomb partition in S2; compared with the products prepared by the traditional honeycomb partitions of the same area, the stress in the large stress area is reduced, and the stress in each area is less than 20ksi, which avoids the problem of large cold accumulated residual stress in the prior art, which is easy to cause local cracking; in addition to reducing the stress in the large stress area, for the area with smaller stress, the size of the original honeycomb partition is appropriately increased, and the number of honeycomb partitions is reduced, so that the stress in each area of ​​the product is more average, and the stress unevenness between the areas is reduced; in addition, since the number of honeycomb partitions is not increased, the jump path is not increased, which ensures a faster laser scanning speed and printing speed, and overcomes the defect of slow printing speed in traditional chessboard scanning or honeycomb scanning; compared with traditional chessboard scanning or honeycomb partition scanning with fixed honeycomb unit size, the present invention improves printing efficiency while reducing the difference in residual stress.

[0162] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A fast printing method based on adaptive honeycomb partitioning, characterized in that: include: Analyze the printed product through stress simulation software to obtain the stress distribution diagram of the area to be printed; Construct honeycomb partitions with the same honeycomb unit size in the same printing coordinate system to cover the area to be printed; Based on the stress distribution map of the area to be printed, the honeycomb cell sizes of the honeycomb partitions with the same honeycomb cell size in the printing area are adaptively adjusted to obtain adaptive honeycomb partitions with more balanced stress distribution; A printed product is obtained based on the adaptive honeycomb partitions as a printing trajectory.

2. The method according to claim 1, characterized in that: Based on the stress distribution map of the area to be printed, the honeycomb partitions with the same honeycomb unit size in the printing area are adaptively adjusted to obtain adaptive honeycomb partitions with more balanced stress distribution, including: adjusting the vertex positions of the honeycomb partitions according to the stress distribution map of the area to be printed, so that the elastic potential energy of the spring system composed of the vertices in any two honeycomb partitions is basically the same.

3. The method according to claim 2, characterized in that Adaptive honeycomb partitioning to achieve more balanced stress distribution includes: S301: constructing a double-mass spring system by grouping adjacent vertices in the honeycomb partition into two groups, and calculating the elastic potential energy of the spring system; S302: Calculate the resultant force of the three adjacent vertices of the vertex of the honeycomb partition, and obtain the resultant force of the vertices of all honeycomb partitions S303: Displace the vertices of all honeycomb partitions in the direction of the resultant force they are subjected to S304: Yes Numerical judgment of: When the displacement of all vertices of the honeycomb partition If the value of is less than e, the honeycomb partition completes the adaptive change, and the connection line of the honeycomb partition vertices can be used as a printing track; When the displacement of all vertices of the honeycomb partition If the value of ≥ e, the cell partition has not completed the adaptive change, and S301-S303 are repeated until The value of is less than e.

4. The method according to claim 3, characterized in that The calculation of the elastic potential energy of the spring system in S301 includes: The energy density U of all spring systems is obtained from the stress distribution diagram at each position of the honeycomb partition side length; The energy density U of all spring systems is integrated at each position of the honeycomb partition side to obtain the elastic potential energy of each spring system.

5. The method according to claim 4, characterized in that The calculation of the elastic potential energy of the spring system in S301 includes: S3011: Convert the stress distribution diagram into a two-dimensional plane coordinate system with the distance between the two end points of the spring system as a variable and the stress as a dependent variable; S3012: Subdivide the line segment of the distance between the two end points of the spring system into multiple small segments, and the distance between each small segment is δ; S3013: According to the center point of each small segment, find the stress of the point on the stress distribution diagram as the average stress σ of the small segment; S3014: according to the calculation formula of energy density, based on the average stress σ, calculate and obtain the average value of the energy density U of the small segment; S3015: multiplying the average value of the energy density U of the small segment by the length δ of the small segment to obtain the strain energy E1 of the small segment; S3016: Based on the above steps, the strain energies of all small segments are obtained, and the elastic potential energy of the spring system is obtained by summing up the strain energies of all small segments.

6. The method according to claim 5, characterized in that The calculation formula of energy density in S3014 satisfies: Where E is the Young's modulus of the material.

7. The method according to claim 5, characterized in that S3012 can be 0.0005 to 0.002 of the distance between the two end points of the spring system.

8. The method according to claim 3, characterized in that S303 includes: based on the vertex coordinates of the honeycomb partitions, processing the vertices of all honeycomb partitions in sequence from one side to the other side of the area to be printed.

9. The method according to claim 8, characterized in that The vertex coordinates based on the honeycomb partitions include: comparing and screening the vertex coordinates, horizontal coordinates and vertical coordinates of all honeycomb partitions, and further determining the processing order of the vertex coordinates of all honeycomb partitions according to the sorting results.

10. The method according to any one of claims 1 to 9, characterized in that: The printed product is prepared by printing using the following method, including: a scanning track adopts a honeycomb partition with a fixed honeycomb unit size.

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