A fusion cell structure, a dot matrix structure, a design method and a manufacturing method

Abstract

This application relates to a fusion of unit cell structure, lattice structure, design method, and manufacturing method, applied in the fields of additive manufacturing and structural design. It includes a P-type structural component providing continuous through-holes and a basic spatial frame, and an IWP-type structural component improving stiffness distribution characteristics in the axial direction. The P-type and IWP-type structural components form a fusion matrix through topological complementarity. The technical advantages of this application are: relying on the topological complementarity of the P-type structural component providing continuous through-holes and a basic spatial frame and the IWP-type structural component improving stiffness distribution characteristics in the axial direction, it has advantages such as uniform stress distribution, good isotropy, strong structural integrity, good pore connectivity, and high process controllability. Under relatively low density conditions, it simultaneously achieves lightweight advantages with high load-bearing capacity and high energy absorption performance, meeting the comprehensive requirements of multi-directional load-bearing capacity, high energy absorption, and good isotropy, thus possessing significant economic and social benefits.

Description

Technical Field

[0001] This application relates to the fields of additive manufacturing and structural design technology, and in particular to a method for integrating unit cell structure, lattice structure, design method and manufacturing method. Background Technology

[0002] The synergistic design of lightweight and high performance is one of the core development directions in high-end equipment fields such as aerospace, biomedicine, and rail transportation. Triply Periodic Minimal Surface (TPMS) lattice structures have become a research hotspot in lightweight structural design due to their continuous and smooth surface topology, absence of sharp nodes, three-dimensional fully connected pores, and excellent specific strength, specific stiffness, and energy absorption characteristics.

[0003] Different topological types of TPMS structures exhibit distinctly different mechanical response characteristics. P-type structures possess higher Young's modulus along the diagonal of the cube, while IWP-type structures exhibit higher Young's modulus along the axial direction of the cube. Existing research largely focuses on improving mechanical properties by adjusting the relative density of a single TPMS structure. However, under low-density conditions (relative density <30%), simply increasing the density leads to a significant decrease in lightweighting, while maintaining a low density results in insufficient load-bearing capacity and a tendency for overall instability. A single topological structure cannot simultaneously meet the comprehensive requirements of multi-directional load-bearing capacity, high energy absorption, and good isotropy. Summary of the Invention

[0004] To help solve the problem that a single topology cannot simultaneously meet the comprehensive requirements of multi-directional load-bearing capacity, high energy absorption, and good isotropy, this application provides a fused unit cell structure, which adopts the following technical solution: it includes a P-type structural part for providing continuous through-holes and a basic spatial frame, and an IWP-type structural part for improving the stiffness distribution characteristics in the axial direction. The P-type structural part and the IWP-type structural part form a fused matrix through topological complementarity.

[0005] In one specific implementation, the relative density of the P-type structural portion located in the fusion substrate is a first relative density of 10%, and the relative density of the IWP-type structural portion located in the fusion substrate is a second relative density of 20%.

[0006] In one specific feasible implementation, the level set constant C of the first relative density of the P-type structural portion -P Through the implicit function cosx + cosy + cosz = C -P definition,

[0007] The horizontal set constant C of the second relative density of the IWP-type structural part -IWPThrough the implicit function 2[cosxcosy+cosycosz+coszcosx]-[cos2x+cos2y+cos2z]=C -IWP definition.

[0008] In one specific implementation scheme, a lattice structure includes the aforementioned fused unit cell structure, wherein a plurality of the fused unit cell structures are periodically arranged and connected in three-dimensional space to form a lattice structure.

[0009] In one specific feasible implementation, a design method is provided for designing the above-mentioned lattice structure, characterized in that the method includes: Implicit function models for P-type and IWP-type structural parts are established, and the level set constants are adjusted to make the relative density of the P-type structural part 10% and the relative density of the IWP-type structural part 20%. The P-type structural unit and the IWP-type structural unit are imported into implicit modeling software, arranged in the same spatial domain, and the initial fusion matrix is ​​obtained by Boolean addition. The initial fusion matrix was subjected to inner wall trimming and smoothing transition treatment to obtain a P+IWP type fusion unit cell structure with continuous pores and smooth interface. The P+IWP type fused unit cell structure is periodically arrayed to form a lattice structure model of the target size.

[0010] In a specific feasible implementation, the steps of arranging overlapping components within the same spatial domain and obtaining the initial fusion matrix using Boolean addition include: The initial fused matrix is ​​obtained using Boolean addition based on the symbolic distance field (SDF), and its expression is as follows:

[0011] in, SDF for P-type structural parts; SDF for IWP type structural parts; This represents the value of SDF at point x in three-dimensional space; This represents the SDF value at position x of the union formed by the P-type structural part and the IWP-type structural part through Boolean addition.

[0012] In one specific feasible implementation, in the step of performing inner wall trimming and smoothing transition treatment on the initial fusion substrate to obtain a P+IWP type fusion unit cell structure with continuous channels and smooth interface: the inner wall trimming treatment includes removing the solid located inside the P-type structure in the initial fusion substrate.

[0013] In one specific implementation, the inner wall trimming process includes the step of removing the solid within the P-type structure in the initial fusion matrix, comprising: The SDF of the complementary structure of the P-type structural part to be removed is defined as follows:

[0014] in, For the implicit function of the original P-type structure; This indicates that the solid and porous regions of the P-type structure are interchanged; C is an offset constant used to adjust the inner wall thickness of the channel after trimming.

[0015] In one specific feasible implementation, the step of performing inner wall trimming and smoothing transition treatment on the initial fusion substrate to obtain a P+IWP type fusion unit cell structure with continuous channels and smooth interfaces includes: the smoothing transition treatment includes: The original SDF of the P-type and IWP-type structural parts are offset at equal intervals to reserve space for a smooth transition. The expression is as follows:

[0016] Where r is the offset radius; i represents two structures to be merged, namely the P-type structure part numbered 1 and the IWP-type structure part numbered 2; Represents the implicit function of the i-th structure; This represents the equidistant implicit function value after offset radius r, i.e., the original implicit function. The new function value is obtained by subtracting the offset radius r at the spatial point X.

[0017] In one specific feasible implementation, a manufacturing method for manufacturing the above-mentioned lattice structure is characterized in that the method includes: Based on the design parameters, complete the single-cell modeling of the fused single-cell structure, and form an overall lattice structure in three-dimensional space array; Import the overall lattice structure model of the 3D model into the additive manufacturing equipment, perform slicing, and set the printing process parameters. Using selective laser melting technology, metal powder is used as raw material and melted and printed layer by layer according to preset printing process parameters to obtain an integrated dot matrix structure; The lattice structure after molding is subjected to powder removal, heat treatment, and surface polishing. Mechanical tests were conducted on the prepared lattice structure.

[0018] In summary, this application has the following beneficial technical effects: relying on the topological complementarity of the P-type structural part that provides continuous through-holes and basic spatial frame and the IWP-type structural part that improves the stiffness distribution characteristics in the axial direction, it has the advantages of uniform stress distribution, good isotropy, strong structural integrity, good pore connectivity and high process controllability. Under the condition of low relative density, it simultaneously takes into account the advantages of lightweight and high load-bearing and high energy absorption performance, meets the comprehensive requirements of multi-directional load-bearing, high energy absorption and good isotropy, and has significant economic and social benefits. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a single cell of a P-type structural part.

[0020] Figure 2 This is a schematic diagram of a single cell of an IWP-type structural part.

[0021] Figure 3 This is a schematic diagram of the initial fusion matrix after the 10% P-type structural part and the 20% IWP-type structural part overlap.

[0022] Figure 4 This is a schematic diagram of an internal P-type structure that complements the 10% P-type structure.

[0023] Figure 5 This is a schematic diagram of a P+IWP unit cell.

[0024] Figure 6 This is a schematic diagram of a P+IWP type fused unit cell formed by Boolean addition for inner wall trimming.

[0025] Figure 7 This is a schematic diagram illustrating the principle of smooth transition in the interface.

[0026] Figure 8 This is a schematic diagram of the 4×4×4 dot matrix structure after arraying.

[0027] Figure 9 This is a schematic diagram of the numerical analysis and experimental evaluation process for lattice structures.

[0028] Figure 10 This is a schematic diagram of quasi-static compression deformation of a lattice structure.

[0029] Figure 11 This is a schematic diagram comparing the compressive stress-strain curves and data of the TPMS-integrated lattice structure and the traditional lattice structure.

[0030] Figure 12 A schematic diagram showing the quasi-static compressive stress-strain curves and data comparisons for different SLM forming directions.

[0031] Figure 13 Schematic diagram of quasi-static compressive stress-strain curves and mechanical property parameters for different SLM forming directions. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1-13 This application will be described in further detail.

[0033] Embodiment 1 of this application discloses a fused unit cell structure.

[0034] Example 1 Reference Figure 1 and Figure 2 The fused unit cell structure comprises a P-type structural component providing continuous through-holes and a basic spatial frame, and an IWP-type structural component enhancing stiffness distribution in the axial direction. These two components form a fused matrix through topological complementarity. Therefore, relying on the topological complementarity between the P-type structural component providing continuous through-holes and a basic spatial frame and the IWP-type structural component enhancing stiffness distribution in the axial direction, it offers advantages such as uniform stress distribution, good isotropy, strong structural integrity, excellent pore connectivity, and high process controllability. Under low relative density conditions, it simultaneously achieves lightweight advantages with high load-bearing capacity and high energy absorption performance, meeting the comprehensive requirements of multi-directional load-bearing capacity, high energy absorption, and good isotropy. It can be widely applied in lightweight aerospace components, biomedical implants, buffer energy-absorbing components, and high-efficiency heat exchange devices, demonstrating significant economic and social benefits.

[0035] Reference Figure 3 and Figure 4 In this embodiment, the relative density of the fused unit cell structure is controlled by adjusting the level set constants of the P-type structure and the IWP-type structure. The relative density of the P-type structure located in the fused matrix is ​​the first relative density, which is 10%. The relative density of the IWP-type structure located in the fused matrix is ​​the second relative density, which is 20%. The length, width and height of the P-type structure and the IWP-type structure in space are both 5 mm.

[0036] Specifically, the horizontal set constant C of the first relative density of the P-type structure. -P Through the implicit function cosx + cosy + cosz = C -P Define the level set constant C of the second relative density of the IWP-type structural part. -IWP Through the implicit function 2[cosxcosy+cosycosz+coszcosx]-[cos2x+cos2y+cos2z]=C -IWP definition.

[0037] The implementation principle of Embodiment 1 of this application is as follows: A TPMS unit cell is integrated, using a P-type structural component with a relative density of 10% as the matrix and an IWP-type structural component with a relative density of 20% as the reinforcing phase. Two types of basic units are obtained through level set constant control and are arranged in overlapping configuration within the same spatial domain. The two types are topologically complementary, balancing multi-directional load-bearing capacity. This facilitates solutions to the problems of significant anisotropy in single TPMS structures, discontinuous interfaces in heterogeneous structures, and insufficient means of controlling the comprehensive performance of low-density lattices. With a total relative density of <30%, while maintaining the advantage of lightweight design, the synergy between the matrix and the reinforcing phase significantly improves structural stiffness, plateau stress, and specific energy absorption, balancing lightweight advantages with high load-bearing capacity and high energy absorption performance, thus meeting the comprehensive requirements of multi-directional load-bearing capacity, high energy absorption, and good isotropy.

[0038] Example 2 Embodiment 2 of this application discloses a lattice structure.

[0039] Reference Figure 5 , Figure 6 , Figure 7 and Figure 8 The above-mentioned fused unit cell structure is included. Several fused unit cell structures are periodically arranged and connected in three-dimensional space to form a lattice structure. The lattice structure can be parametrically adjusted in terms of unit cell size, array quantity and spatial arrangement according to the load-bearing requirements. No restrictions are imposed here. In this embodiment, a 4×4×4 lattice structure is used as an example for illustration.

[0040] The implementation principle of Embodiment 2 of this application is as follows: The unit cell surface of the lattice structure in this embodiment is a continuous curved surface without sharp edges, and the internal pores are interconnected, making it suitable for the discharge of unmelted powder and integrated forming by additive manufacturing. The lattice structure can be used as an independent lattice sample, or for the partial reconstruction and partition filling of complex load-bearing components. It is especially suitable for parts that have common requirements for structural continuity, lightweighting, and manufacturability. It can be used as the lattice core material for aero-engine brackets, lightweight load-bearing shells, or locally filled areas to achieve a coordinated design of weight reduction and load-bearing capacity while ensuring structural continuity.

[0041] Example 3 Embodiment 3 of this application discloses a design method.

[0042] Reference Figure 5 , Figure 6 , Figure 7 and Figure 8 A design method for designing the above-mentioned lattice structure, characterized in that the method includes: Step 1: Establish implicit function models for the P-type and IWP-type structural parts, and adjust the level set constants to make the relative density of the P-type structural part 10% and the relative density of the IWP-type structural part 20% respectively; Step 2: Import the P-type structural part and the IWP-type structural part into the implicit modeling software, arrange them in the same spatial domain, and use Boolean addition to obtain the initial fusion matrix; Step 21: Boolean addition, through implicit modeling and signed distance field (SDF) operations, obtains the initial fused matrix using Boolean addition based on the signed distance field (SDF), the expression of which is:

[0043] Where d represents the Signed Distance Field (SDF), which is a function describing the shortest distance from a point to the cell surface. A positive value indicates that the point is outside the cell, and a negative value indicates that the point is inside the cell; P represents a P-type structural unit cell, which is the P-type geometry of the structural unit; IWP represents an IWP-type structural unit cell, which is the IWP geometry of the structural unit; x represents the position vector in space or the coordinates of the mesh node, which is the value of the SDF at a point x in three-dimensional space; union(x) represents the SDF value at position x of the union formed by Boolean summation of two structural unit cells. SDF for P-type structural parts; SDF for IWP type structural parts; This represents the value of SDF at point x in three-dimensional space; This represents the SDF value at position x of the union formed by the P-type structural part and the IWP-type structural part through Boolean addition.

[0044] However, directly using the minimum value of the above expression leads to sharp transition edges in the fused unit cell structure. Therefore, a smoothing function for the mixed transition region needs to be introduced. This invention employs a Rounded smoothing function, which is based on an implicit field offset and smoothing mixing method for generating fused surfaces to achieve a continuous transition between heterogeneous lattice structures. This method is based on a signed distance field and introduces a smooth transition within the fused region through equidistant surface calculation and a rounded corner mixing strategy, thereby ensuring tangential continuity at the geometric connection.

[0045] Step 3: Perform inner wall trimming and smoothing treatment on the initial fusion matrix to obtain a P+IWP type fusion unit cell structure with continuous pores and smooth interface. Step 31, the inner wall trimming process includes removing the solid within the P-type structure in the initial fused matrix. Let the implicit function of the original P-type structure cell be... Its zero isosurface =0 indicates the unit cell boundary. <0 indicates the interior of the unit cell. >0 indicates the outside of the unit cell. To obtain the complementary region inside the unit cell of the P-type structure, the SDF of the complementary structure of the P-type structure to be removed is defined, and its expression is:

[0046] in, For the implicit function of the original P-type structure; This indicates that the solid and porous regions of the P-type structure are interchanged, making the original interior of the unit cell the exterior and the exterior the interior; C is an offset constant used to adjust the thickness of the inner wall of the channel after modification. C is an offset value used to adjust the thickness or gap of the complementary structure to ensure that the generated structure matches the unit cell of the original P-type structure.

[0047] Step 32, the smooth transition processing includes: assuming the two P-type and IWP-type structures to be merged are described by implicit functions, their zero isosurfaces are defined as the boundaries of the corresponding structures. The smooth transition processing is implemented using a mixing function based on a signed distance field, and the fusion interface adopts a rounded continuous transition method, enabling tangential continuous connection between different topologies at the interface. The original SDFs of the P-type and IWP-type structures are equidistantly offset to reserve space for the smooth transition; the expression is as follows:

[0048] Where r is the offset radius, this operation is geometrically equivalent to a sphere of radius r rolling on the original surface, which can effectively eliminate sharp geometric features and provide transition space for subsequent fusion; i represents two structures to be fused, namely the P-type structure part numbered 1 and the IWP-type structure part numbered 2. Let the implicit function of the i-th structure have its zero isosurface. =0 defines the structural boundary; This represents the equidistant implicit function value after offset radius r, i.e., the original implicit function. The new function value is obtained by subtracting the offset radius r at the spatial point X.

[0049] Step 4: Periodically array the P+IWP type fused unit cell structure to form a lattice structure model of the target size.

[0050] Reference Figures 9-13 To further demonstrate that the lattice structure in the embodiments of this application has high load-bearing capacity and high energy absorption capacity, the sample was subjected to a uniaxial quasi-static compression test with a loading rate of 1 mm / min. Figure 10 The study demonstrates a comparison of deformation between TPMS lattice structure simulation (FE) and experimental (EXP) data.

[0051] Figure 11This paper presents a comparison of the compressive performance of the TPMS lattice structure and the traditional lattice structure in the embodiments of this application. All three structures exhibit a rapid increase in elastic deformation during the initial stage of compression, followed by plateau deformation or gradual strengthening. It can be seen that the stress level of the P+IWP fused lattice structure is consistently higher than that of the single IWP lattice and the single P lattice. When the strain reaches 50%, the compressive stress of the P+IWP structure is approximately 270 MPa, significantly higher than that of the IWP and P structures. This indicates that the P+IWP fused unit cell structure has higher load-bearing capacity and stronger resistance to compressive deformation. In contrast, the stress level of the IWP lattice structure is moderate, while that of the P lattice structure is the lowest, indicating that the mechanical properties of a single topology structure are relatively limited. The advantage of the P+IWP fused unit cell structure lies in combining the geometric features of two TPMS structures to form a more complex, continuous, and stable load transfer path. This structure can improve overall stiffness and compressive strength, while maintaining continuous load-bearing capacity during large deformation stages, demonstrating its good energy absorption capacity and resistance to instability.

[0052] Figure 12 This diagram illustrates the quasi-static compressive stress-strain curves and data comparisons for different SLM forming directions, showcasing the deformation morphology evolution of the P+IWP lattice structure under varying SLM forming directions with increasing compressive strain. The top row represents specimens parallel to the forming direction (" / / "), and the bottom row represents specimens perpendicular to the forming direction ("⊥"). As the compressive strain increases from 0% to 60%, both types of specimens undergo initial structural integrity, local buckling, pore collapse, interlaminar crushing, and final densification. At ε=10%, slight compressive deformation begins to occur, but the overall pore morphology remains relatively intact. At ε=30% and 40%, significant bending and local collapse of the lattice units occur, and the pores gradually shrink. At ε=60%, the structure enters the densification stage, and the pores are essentially compacted. Comparing the top and bottom rows reveals differences in the collapse pattern and deformation uniformity of the structure under different forming directions, indicating that the SLM forming direction affects the compressive failure behavior of the lattice structure. Figure 12 This diagram not only illustrates the final failure result but also the continuous deformation process at different strain stages, providing a clear understanding of the failure evolution mechanism of the P+IWP lattice structure during compression. Compared to a simple stress-strain curve, this diagram more clearly demonstrates how the structure gradually evolves from elastic deformation to local collapse and overall densification. Furthermore, by comparing the parallel and perpendicular directions, the diagram visually reflects the influence of the SLM forming direction on structural stability, collapse mode, and load-bearing deformation behavior.

[0053] Figure 13This diagram illustrates the quasi-static compressive stress-strain curves and mechanical property parameters for different SLM forming directions. The black curve represents the specimen in the P+IWP ⊥ direction, and the red curve represents the specimen in the P+IWP / / direction. Both curves rise rapidly in the initial stage of compression, indicating that the specimens in both directions have high initial load-bearing capacity. Subsequently, the curves show stress decrease and fluctuation, which indicates local buckling, fracture, or lamellar collapse of the lattice elements. The curve changes show that the stress rise is more significant in the P+IWP " / / " direction specimen as the strain increases in the later stages, with the final compressive stress reaching approximately 770 MPa, indicating stronger load-bearing capacity during large deformation and densification stages. The curve of the P+IWP "⊥" direction specimen shows relatively smaller fluctuations and a more stable plateau stage, indicating a relatively stable compression deformation process. The differences between the two directions indicate that the SLM forming direction affects the yield behavior, collapse mode, plateau stress, and load-bearing capacity during the densification stage of the structure. The red curve shows that the specimen in the / / direction has a higher final load-bearing capacity during the high strain stage, while the black curve shows that the specimen in the ⊥ direction has a smoother compression plateau and better deformation stability. This is of reference value for subsequent selection of SLM printing direction and optimization of lattice structure service performance.

[0054] according to Figure 12 and Figure 13 It can be seen that the fused unit cell structure exhibits minimal performance fluctuations under different SLM printing orientations, with uniform stress distribution and strong overall integrity. The specific energy absorption (SEA) and plateau stress of the fused TPMS lattice structure are 7.98 J / g and 272.69 MPa, respectively, indicating that the fused TPMS lattice structure is significantly superior to the traditional structure in terms of both plateau stress and specific energy absorption.

[0055] The implementation principle of Embodiment 3 of this application is as follows: In the unit cell construction stage, after forming the external fusion skeleton using Boolean addition, the internal redundant areas are then trimmed to maintain the continuity of the original P-type channels. Subsequently, a smoothing mixing function based on the signed distance field SDF is used to perform rounded corner continuous transition processing on the interface, reducing the risk of stress concentration in the boundary area. Relying on the topological complementarity between the P-type structural part and the IWP-type structural part, a clear implementation route is provided for the design of low-density fusion unit cell structure; through implicit function modeling and smoothing fusion processing, the resulting structure has continuous curved surfaces and connected channels, which facilitates additive manufacturing and subsequent powder removal processes.

[0056] Example 4 Embodiment 4 of this application discloses a manufacturing method.

[0057] A manufacturing method for manufacturing the above-mentioned lattice structure, characterized in that the method includes: Step 1: Complete the single-cell modeling of the fused single-cell structure according to the design parameters, and form an overall lattice structure in a three-dimensional spatial array.

[0058] Step 2: Import the overall lattice structure model of the 3D model into the additive manufacturing equipment, perform slicing, and set the printing process parameters.

[0059] Step 3 involves using selective laser melting (SLM) with metal powder as the raw material. The powder is melted and printed layer by layer according to preset printing process parameters to obtain an integrated dot matrix structure. Specifically, in this embodiment, TA15 titanium alloy powder is used. A checkerboard scanning strategy is employed, with the laser beam rotating 67° layer by layer. The process parameters include a laser power of 300 W, a scanning speed of 1200 mm / s, a scanning spacing of 120 μm, and a powder layer thickness of 30 μm.

[0060] Step 4: Remove powder, heat treat and polish the surface of the formed lattice structure.

[0061] Step 5: Conduct mechanical tests on the prepared lattice structure. Specifically, the mechanical tests can employ relevant techniques to evaluate the equivalent stiffness, load-bearing response, and forming quality of the structure, such as numerical homogenization analysis, quasi-static compression tests, and finite element simulations of the TPMS lattice structure.

[0062] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A fused unit cell structure, characterized in that: It includes a P-type structural component for providing continuous through-holes and a basic spatial frame, and an IWP-type structural component for improving the stiffness distribution characteristics in the axial direction. The P-type structural component and the IWP-type structural component form a fused matrix through topological complementarity.

2. The fused unit cell structure according to claim 1, characterized in that: The relative density of the P-type structural portion located in the fusion substrate is the first relative density, which is 10%, and the relative density of the IWP-type structural portion located in the fusion substrate is the second relative density, which is 20%.

3. The fused unit cell structure according to claim 2, characterized in that: The horizontal set constant C of the first relative density of the P-type structural part -P Through the implicit function cosx + cosy + cosz = C -P Define the level set constant C of the second relative density of the IWP-type structural part. -IWP Through the implicit function 2[cosxcosy+cosycosz+coszcosx]-[cos2x+cos2y+cos2z]=C -IWP definition.

4. A lattice structure, characterized in that: It includes the fusion unit cell structure as described in any one of claims 1 to 3, wherein a plurality of the fusion unit cell structures are periodically arranged and connected in three-dimensional space to form a lattice structure.

5. A design method for designing the lattice structure of claim 4, characterized in that: The methods include: Implicit function models for P-type and IWP-type structural parts are established, and the level set constants are adjusted to make the relative density of the P-type structural part 10% and the relative density of the IWP-type structural part 20%. The P-type structural unit and the IWP-type structural unit are imported into implicit modeling software, arranged in the same spatial domain, and the initial fusion matrix is ​​obtained by Boolean addition. The initial fusion matrix was subjected to inner wall trimming and smoothing transition treatment to obtain a P+IWP type fusion unit cell structure with continuous channels and smooth interface. The P+IWP type fused unit cell structure is periodically arrayed to form a lattice structure model of the target size.

6. The design method according to claim 5, characterized in that: The steps for arranging overlapping components within the same spatial domain and obtaining the initial fusion matrix using Boolean addition include: The initial fused matrix is ​​obtained using Boolean addition based on the symbolic distance field (SDF), and its expression is as follows: in, SDF for P-type structural parts; SDF for IWP type structural parts; This represents the value of SDF at point x in three-dimensional space; This represents the SDF value at position x of the union formed by the P-type structural part and the IWP-type structural part through Boolean addition.

7. The design method according to claim 5, characterized in that: In the step of performing inner wall trimming and smoothing transition treatment on the initial fusion substrate to obtain a P+IWP type fusion unit cell structure with continuous channels and smooth interface: the inner wall trimming treatment includes removing the solid inside the P-type structure in the initial fusion substrate.

8. The design method according to claim 6, characterized in that: The internal wall finishing process, which includes the step of removing solids located inside the P-type structural portion of the initial fusion matrix, includes: The SDF of the complementary structure of the P-type structural part to be removed is defined as follows: in, For the implicit function of the original P-type structure; This indicates that the solid and porous regions of the P-type structure are interchanged; C is an offset constant used to adjust the inner wall thickness of the channel after trimming.

9. The design method according to claim 5, characterized in that: In the step of performing inner wall trimming and smoothing treatment on the initial fused matrix to obtain a P+IWP type fused unit cell structure with continuous channels and smooth interfaces, the smoothing treatment includes: The original SDF of the P-type and IWP-type structural parts are offset at equal intervals to reserve space for a smooth transition. The expression is as follows: Where r is the offset radius; i represents two structures to be merged, namely the P-type structure part numbered 1 and the IWP-type structure part numbered 2; Represents the implicit function of the i-th structure; This represents the equidistant implicit function value after offset radius r, i.e., the original implicit function. The new function value is obtained by subtracting the offset radius r at the spatial point X.

10. A manufacturing method for manufacturing the lattice structure of claim 4, characterized in that: The methods include: Based on the design parameters, complete the single-cell modeling of the fused single-cell structure, and form an overall lattice structure in a three-dimensional spatial array. Import the overall lattice structure model of the 3D model into the additive manufacturing equipment, perform slicing, and set the printing process parameters. Using selective laser melting technology, metal powder is used as raw material and melted and printed layer by layer according to preset printing process parameters to obtain an integrated dot matrix structure; The shaped lattice structure is then subjected to powder removal, heat treatment, and surface polishing. Mechanical tests were conducted on the prepared lattice structure.

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