A Bouligand spiral stacking structure and preparation method thereof

Abstract

The present invention discloses a Bouligand spiral stacking structure and a preparation method thereof, which relates to the field of additive manufacturing. First, a three-dimensional simulation model of the Bouligand spiral stacking structure is established; the three-dimensional simulation model is two-dimensionalized to obtain two-dimensional slice data; the two-dimensional slice data is input into a laser selective melting device for calculation processing to obtain a motion trajectory of the printer; printing preparation is performed in the laser selective melting device; the three-dimensional simulation model is printed according to the motion trajectory to obtain the Bouligand spiral stacking structure. The present invention utilizes the characteristics of the laser selective melting process, which is fast, less constrained, and high-precision rapid prototyping of complex structures, to prepare a Bouligand structure with a complex structure that is difficult to form with traditional material processing technology but has excellent innate comprehensive mechanical properties, thereby improving the preparation accuracy and preparation efficiency.

Description

Technical Field

[0001] The present invention relates to the field of additive manufacturing, and in particular to a Bouligand spiral stacking structure and a preparation method thereof. Background Art

[0002] The survival of the fittest in the process of billions of years of evolution in nature has directly provided humans with a variety of biological structures with excellent performance. Honeycomb and Bouligand are two famous natural biological structures. As a typical porous structural material, the former has extremely excellent structural properties due to its higher porosity and lower mass density compared to its matrix material. For example, it has a high stiffness-to-weight ratio and strength-to-weight ratio, and also has good energy absorption characteristics and excellent impact protection capabilities. Driven by the ever-increasing engineering requirements, a single honeycomb structure can no longer meet the needs of production and life, thus giving rise to many honeycomb designs for improving its mechanical properties. Studies have shown that compared with traditional uniform honeycombs, honeycomb structures that match functional gradient performance have stronger mechanical properties, lower mass density, and higher stiffness, strength, energy absorption and impact resistance. That is, gradient honeycombs have better mechanical properties than uniform honeycombs. At the same time, the discovery and extraction of Bouligand structures in biology also provides reference ideas for the engineering field. It was first discovered in the exoskeleton of crustaceans. It is a natural material formed by twisted plywood arrangement and spirally stacked unidirectional nanofiber thin layers, showing excellent mechanical functions. Bouligand's structure, with tightly arranged fibers, periodic fiber stacking, and continuous rotation of adjacent layers at a certain angle, shows extraordinary toughness and damage resistance, and also has broad application prospects in various advanced engineering structural materials in the future. Although the two biological structures provide ready-made and potentially excellent material structure design ideas, they are limited by the accuracy and efficiency of traditional material processing and molding. The rapid and precise, target structure integrated molding technology of additive manufacturing provides corresponding operability for the preparation of the above complex structures.

[0003] Selective laser melting (SLM) is one of the additive manufacturing processes, which uses a laser beam to melt and fuse metal powder together. The process can be briefly described as follows: a thin layer of powder is deposited on a substrate or a previously deposited layer, and the laser beam selectively melts the metal powder layer by layer according to the contour data, melts and fuses the powder particles, and finally prints out the solid parts by selectively melting layer by layer from bottom to top. This process can produce parts with complex structures and high precision without the help of traditional molds, tools, fixtures and multiple processing steps. On the one hand, it can achieve "net shaping" of materials, greatly improving material utilization; at the same time, the forming process can be controlled by information technology without subsequent processing, which can meet some special requirements and greatly shorten the processing cycle. Most of the metal parts manufactured by SLM technology have high dimensional accuracy, high surface quality and density close to 100%. For example, compared with traditional casting, alloys formed by SLM technology have better mechanical properties, and only simple heat treatment can obtain better ductility. As the most promising additive manufacturing technology, SLM is used in the fields of aerospace, biomedicine, automobile manufacturing and various manufacturing links. Summary of the invention

[0004] The object of the present invention is to provide a Bouligand spiral stacking structure and a preparation method thereof, so as to improve the precision and efficiency of the preparation of the Bouligand structure.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A Bouligand spiral stacking structure, comprising a Bouligand spiral stacking matrix structure and a honeycomb structure with gradient changes;

[0007] The Bouligand spiral stacking matrix structure comprises a plurality of elementary structures which are stacked in sequence and rotated in the same direction at a preset angle; the elementary structure comprises a plurality of hollow cylindrical tubes which are closely arranged in the same direction;

[0008] The honeycomb structure with gradient changes is filled in each of the hollow cylindrical tubes.

[0009] Optionally, the preset angle range is 8 ° ≤α≤15 ° .

[0010] A method for preparing a Bouligand spiral stacking structure, comprising:

[0011] Establishing a three-dimensional simulation model of the Bouligand spiral stacking structure;

[0012] Performing two-dimensional processing on the three-dimensional simulation model to obtain two-dimensional slice data;

[0013] The two-dimensional slice data is input into a laser selective melting device for calculation processing to obtain a motion trajectory of the printer;

[0014] Performing printing preparation work in the laser selective melting device;

[0015] The three-dimensional simulation model is printed according to the motion trajectory to obtain a Bouligand spiral stacking structure.

[0016] Optionally, the printing preparation work in the laser selective melting device specifically includes:

[0017] Light alloy powder is filled into the laser selective melting device, laser process parameters are set, and inert gas is filled in.

[0018] Optionally, the three-dimensional simulation model is printed according to the motion trajectory to obtain a Bouligand spiral stacking structure, and then the method further includes:

[0019] The Bouligand spiral stacking structure is subjected to wire cutting, stress relief annealing, cleaning and sandblasting.

[0020] Optionally, the step of establishing the three-dimensional simulation model of the Bouligand spiral stacking structure specifically includes:

[0021] A plurality of hollow cylindrical tubes are closely arranged in the same direction to form a single-layer primitive structure, thereby obtaining a multi-layer primitive structure simulation model;

[0022] The plurality of primitive structure simulation models are sequentially spirally stacked in a vertical direction at a preset angle to obtain a Bouligand spiral stacking matrix structure simulation model;

[0023] Filling the Bouligand spiral stacking matrix structure simulation model with a honeycomb structure having a gradient change to obtain an initial simulation model of the Bouligand spiral stacking structure;

[0024] The initial simulation model is repaired so that each vertex of the outermost honeycomb structure is inscribed in the hollow cylindrical tube, thereby obtaining a three-dimensional simulation model of the Bouligand spiral stacking structure.

[0025] Optionally, the light alloy powder is titanium alloy powder or aluminum alloy powder.

[0026] Optionally, the particle size of the light alloy powder is in the range of 10-55 μm.

[0027] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0028] The present invention provides a Bouligand spiral stacking structure and a preparation method thereof, firstly establishing a three-dimensional simulation model of the Bouligand spiral stacking structure; performing two-dimensional processing on the three-dimensional simulation model to obtain two-dimensional slice data; inputting the two-dimensional slice data into a laser selective melting device for calculation processing to obtain a motion trajectory of a printer; performing printing preparation work in the laser selective melting device; printing the three-dimensional simulation model according to the motion trajectory to obtain a Bouligand spiral stacking structure. The present invention utilizes the characteristics of the laser selective melting process, which is fast, less constrained, and high-precision rapid prototyping of complex structures, to prepare a Bouligand structure with a complex structure that is difficult to form with traditional material processing technology but has excellent innate comprehensive mechanical properties, thereby improving the preparation accuracy and preparation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0030] Figure 1 A schematic diagram of the Bouligand spiral stacking structure provided by the present invention;

[0031] Figure 2 A partial enlarged view of the Bouligand spiral stacking structure provided by the present invention;

[0032] Figure 3 Schematic diagram of a Bouligand spiral stacking structure whose basic structure is a rectangle; wherein (a) is a front view of the Bouligand spiral stacking structure whose basic structure is a rectangle; (b) is a top view of the Bouligand spiral stacking structure whose basic structure is a rectangle; (c) is a side view of the Bouligand spiral stacking structure whose basic structure is a rectangle;

[0033] Figure 4 A schematic diagram of the structure of a single hollow cylindrical tube with a Bouligand spiral stacking structure filled with a gradient honeycomb provided by the present invention;

[0034] Figure 5 It is a schematic diagram of a honeycomb structure with the center of the circle as the center and the thickness increasing from the inside to the outside;

[0035] Figure 6 It is a schematic diagram of a honeycomb structure with a circle as the center and a decreasing thickness from the inside to the outside;

[0036] Figure 7It is a flow chart of the Bouligand spiral stacking structure preparation method of the present invention in practical application;

[0037] Figure 8 A flow chart of the method for preparing the Bouligand spiral stacking structure provided by the present invention;

[0038] Fig. 9 Schematic diagram of repairing the "anisotropy" defect for 3D printing structure-aided design software. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The object of the present invention is to provide a Bouligand spiral stacking structure and a preparation method thereof, so as to improve the precision and efficiency of the preparation of the Bouligand structure.

[0041] In order to overcome the problem of insufficient precision and efficiency in the traditional material processing and forming of natural bionic structures, the present invention provides a method for forming a bionic gradient honeycomb filled Bouligand spiral stacking structure by laser selective melting 3D printing technology. The present invention can accurately parameterize and control the change of the honeycomb wall thickness gradient change morphology, Bouligand spiral angle, printing material components, etc. The obtained 3D printed bionic structure not only has good comprehensive mechanical properties, high titanium alloy strength and light weight, but also combines with the bionic functionality of the honeycomb filled Bouligand structure to meet potential industrial needs.

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Embodiment 1

[0044] like Figure 1 As shown in FIG. 1 , the Bouligand spiral stacking structure of the present invention comprises a Bouligand spiral stacking matrix structure and a honeycomb structure with gradient changes. In this embodiment, the basic structure of the Bouligand spiral stacking structure is circular. A partial enlarged view of the Bouligand spiral stacking structure is shown in FIG. Figure 2 shown.

[0045] The Bouligand spiral stacking matrix structure includes a plurality of elementary structures which are stacked in the same direction and rotated in sequence at a preset angle; the elementary structure includes a plurality of hollow cylindrical tubes which are closely arranged in the same direction. In practical applications, the elementary structure can be in any shape such as a circle, a rectangle, a triangle, etc. The elementary structure is a rectangular Bouligand spiral stacking structure, such as Figure 3 In addition, the Bouligand spiral stacking matrix structure can be formed by stacking a plurality of elementary structures by rotating them in the same direction at a preset angle in sequence, or can be formed by stacking a plurality of elementary structures by rotating them in the same direction linearly or nonlinearly in sequence. In this embodiment, the Bouligand spiral stacking matrix structure is formed by stacking a plurality of elementary structures by rotating them in the same direction at a preset angle in sequence. Specifically, the preset angle range is 8 ° ≤α≤15 ° .

[0046] The honeycomb structure with gradient changes is filled in each of the hollow cylindrical tubes. Figure 4 There are two cases of gradient changes in the honeycomb structure with gradient changes. One is as follows Figure 5 As shown in the figure, with the center of the circle as the center, the thickness of the honeycomb structure increases from the inside to the outside; the other is as follows Figure 6 As shown, with the center of the circle as the center, the thickness of the honeycomb structure decreases from the inside to the outside.

[0047] Embodiment 2

[0048] The present invention provides a method for preparing the Bouligand spiral stacking structure of Example 1, such as Figure 8 As shown, including:

[0049] Step 801: Establishing a three-dimensional simulation model of the Bouligand spiral stacking structure.

[0050] Furthermore, the step 801 specifically includes:

[0051] Step 8011: Arrange multiple hollow cylindrical tubes closely in the same direction to form a single-layer primitive structure, and obtain a multi-layer primitive structure simulation model.

[0052] Step 8012: spirally stacking the multiple layers of the primitive structure simulation models in the vertical direction at a preset angle to obtain a Bouligand spiral stacking matrix structure simulation model.

[0053] In practical applications, the preparation process of the Bouligand spiral stacking structure of the present invention is as follows: Figure 7 As shown, it involves two parts: "additive manufacturing" and "structural design modeling", as follows:

[0054] Step 1: Design of the Bouligand spiral stacking matrix structure. The Bouligand spiral stacking matrix structure is designed using Rhino modeling software and Grasshopper parameter modular plug-in. Multiple hollow cylindrical tubes are closely arranged in the same direction to form a single-layer primitive structure. The primitive structure is spirally stacked in the vertical axis direction, and adjacent layers are rotated and displayed in sequence at the same angle or different angles.

[0055] Preferably, the Bouligand spiral stacking matrix structure is designed. In the step 1, each layer of the Bouligand structure is composed of a plurality of hollow cylindrical tubes arranged in the same direction, and the rotation angles between adjacent layers are fixed (generally a small rotation angle of 8°≤α≤15° is fixed, which makes it easier to obtain better comprehensive mechanical properties) or non-fixed (such as linear, nonlinear) and the like. After a certain number of layers are superimposed, it is regarded as a periodic change.

[0056] Step 8013: Filling the Bouligand spiral stacking matrix structure simulation model with a honeycomb structure having a gradient change to obtain an initial simulation model of the Bouligand spiral stacking structure.

[0057] Step 2: Design a gradient honeycomb filling structure design (gradient honeycomb filling circular tube) through Rhino modeling software and Grasshopper parameter modular plug-in, and fill each hollow cylindrical tube obtained in the structure of the above step 1 with a honeycomb structure with gradient changes in sequence. Among them, the gradient honeycomb filling structure design (gradient honeycomb filling hollow cylindrical tube), the honeycomb structure includes a hollow structure of multiple monomer honeycombs, and is filled and arranged along the axial direction of the hollow cylindrical tube. In particular, in the radial direction of the filled hollow cylindrical tube, the thickness change of each honeycomb monomer can be divided into a thin area of ​​equal thickness, a thick area of ​​equal thickness, and a gradient change area according to the form of change. The center of the gradient change is the center of the bottom surface of the hollow cylindrical tube, and the hexagonal honeycombs at the same radius distance from the center have the same gradient rate, and their honeycomb wall thickness is consistent, so they can be regarded as equal thickness areas. In particular, in the gradient change area, the thickness of a certain point x can be obtained by the power-law function given below:

[0058]

[0059] Where n is the gradient rate; ρ min is the thickness of the thin area of ​​equal thickness, that is, the minimum wall thickness of the honeycomb; ρ max is the thickness value of the uniform thickness zone, that is, the maximum wall thickness of the honeycomb; L is the length of the gradient change interval.

[0060] Steps one and two are the basic steps of “structural design modeling”. After the sub-gradient honeycomb structure in step two is filled, the comprehensive mechanical and mechanical properties are optimized based on the bouligand spiral stacking matrix structure in step one.

[0061] Step 8014: Repair the initial simulation model so that each vertex of the outermost honeycomb structure is inscribed in the hollow cylindrical tube, thereby obtaining a three-dimensional simulation model of the Bouligand spiral stacking structure.

[0062] Step 3: To avoid the anisotropy of the geometric structure of the hexagonal honeycomb structure and the outer cylinder contact part automatically generated by the "array function" when designing with Rhino and its Grasshopper plug-in, such as the outermost hexagonal honeycomb wall and the edge not being able to regularly inscribe the outer cylinder. Further use the Netfabb software "automatic repair", "default repair", "zero void", "zero boundary", "zero reverse normal" and other functional interfaces to improve the target structure, so that the shape of the connection between the honeycomb and the outer cylinder is consistent, such as Fig. 9 After repair, the model will show complete flow and regularity. Each vertex of the outermost hexagonal honeycomb is regularly inscribed in the cylinder, and the honeycomb walls are given structural integrity, which avoids the outer honeycomb wall being cut into two parts by the cylindrical surface, thereby improving the fault tolerance, structural accuracy and comprehensive mechanical properties during printing operations.

[0063] Step 802: convert the three-dimensional simulation model into two-dimensional slice data.

[0064] Step 803: Input the two-dimensional slice data into the laser selective melting device for calculation and processing to obtain the motion trajectory of the printer.

[0065] Step 4: Use additive manufacturing technology to prepare the gradient honeycomb-filled Bouligand spiral stacking structure involved in the present invention, build a three-dimensional model of the required part structure and input it into the additive manufacturing editing software, perform two-dimensional processing after editing, obtain two-dimensional slice data and import it into the auxiliary computer system and software built into the laser selective melting equipment, perform calculation processing, and obtain the motion trajectory of the printer. Finally, the motion trajectory instructions of each layer are sent to the printer power system through the computer.

[0066] Step 804: Perform printing preparation work in the selective laser melting device.

[0067] Furthermore, the step 804 specifically includes:

[0068] Fill the laser selective melting device with light alloy powder, set laser process parameters, and fill with inert gas. Specifically, the light alloy powder is titanium alloy powder (such as Ti 6Al4V) or aluminum alloy powder (such as Al-12Si). The particle size range of the light alloy powder is 10μm-55μm.

[0069] Step 5: Prepare the raw material lightweight alloy powder for printing.

[0070] Step 6: Fill the laser selective melting equipment with light alloy powder and set the corresponding laser process parameters. The laser process parameters include a power range of 100W-500W, a laser scanning speed range of 500mm / s-2000mm / s, a powder layer thickness of 20μm-50μm; a scanning interval of 70μm-120μm; an inert protective gas is introduced into the forming chamber, and the oxygen content is maintained at 100ppm-1000ppm during the laser selective melting process.

[0071] The laser selective melting process is a process in which the laser high-energy heat source and the metal material powder react rapidly. The rapid heating and cooling causes the powder material to melt and solidify rapidly in a short time, which will cause large thermal stress between the material forming area and the formed area. If the laser processing parameters of the part are not selected properly, it will cause surface cracks on the part. Once macro cracks occur, the practicality of the part will be greatly limited. Therefore, in the laser selective melting forming process of the part, the laser process parameters must be strictly selected to obtain a molded part with fewer defects and high comprehensive mechanical properties.

[0072] Step 7: Adjust the substrate to be parallel to the bottom powder slot and determine the best starting position to ensure a good curing effect for the first layer. After confirming that the first layer printing effect is good, start normal printing.

[0073] Step 805: Print the three-dimensional simulation model according to the motion trajectory to obtain a Bouligand spiral stacking structure.

[0074] Furthermore, the step 805 further includes:

[0075] The Bouligand spiral stacking structure is subjected to wire cutting, stress relief annealing, cleaning and sandblasting.

[0076] Step 8: After the laser additive manufacturing is completed, the formed component (Bouligand spiral stacking structure) is subjected to post-processing processes such as wire cutting, stress relief annealing, cleaning, and sandblasting to finally obtain a Bouligand spiral stacking structure with a high-precision and complex structure.

[0077] Preferably, in step eight, the temperature range of the stress annealing treatment for the SLM-formed titanium alloy is 450°C-650°C, and the temperature range of the stress annealing treatment for the SLM-formed aluminum alloy is 240°C-260°C.

[0078] The present invention provides a Bouligand spiral stacking structure and a preparation method thereof, which belong to the field of metal additive manufacturing and bionic structure design. First, a spiral stacking structure is realized using three-dimensional design software, and then a gradient honeycomb is used to fill the spiral stacking microstructure to realize the model design of a multi-level bionic structure; the exported model is repaired, optimized and supported by using special software for additive manufacturing, and imported into the additive manufacturing equipment system in STL format, and titanium alloy powder is configured according to a specific ratio, spread on the laser melting system, and the initial position of the substrate is adjusted and an inert protective gas is introduced before printing layer by layer, and cleaning and polishing are performed after printing. The present invention can accurately parameterize and control the change of honeycomb wall thickness, Bouligand spiral angle, printing material components, etc., and the obtained 3D printed bionic structure has good comprehensive mechanical properties, not only has the characteristics of high strength and light weight of titanium alloy, but also is combined with the functionality of the honeycomb-filled Bouligand structure to meet potential industrial needs.

[0079] Embodiment 3

[0080] In this embodiment, based on step 1 in embodiment 2, the preset angle α of rotation between any two layers of elementary structures of the Bouligand spiral stacking structure is 12 ° , is a fixed value.

[0081] In this embodiment, based on step 2 in embodiment 2, n is the gradient rate, and in particular, n=e≈2.71828 is taken here, where e is a natural constant.

[0082] In this embodiment, based on step 4 in embodiment 2, the additive manufacturing technology used is selective laser melting (SLM).

[0083] In this embodiment, based on step five in embodiment two, the light alloy powder is a titanium alloy (such as Ti6Al4V), and the powder particle size range is 10-55 μm.

[0084] In this embodiment, based on step six in embodiment two, the laser process parameters of the laser selection melting equipment are set, the power is specifically 250W, the laser scanning speed is 1000mm / s, the thickness of a single powder layer is 30μm; and the scanning interval is 100μm.

[0085] In this embodiment, based on step six in embodiment two, when inert gas protection is introduced, the oxygen content is maintained at 100 ppm-1000 ppm during the laser selective melting process.

[0086] In this embodiment, based on step eight in embodiment two, the temperature range of the stress annealing treatment of the SLM formed titanium alloy is 450°C-650°C.

[0087] Embodiment 4

[0088] In this embodiment, based on step 1 in embodiment 2, the Bouligand spiral stacking structure is from bottom to top, and the rotation angle α between the nth layer of the elementary structure and the n+1th layer and the number of layers n satisfy the relationship: α n+1 =α n +β, where β is a customizable angle value. In this example, β=5° is taken so that the rotation angles between adjacent layers satisfy a linear increasing relationship.

[0089] In this embodiment, based on step 2 in embodiment 2, n is the gradient rate. In particular, here we take is the golden ratio number.

[0090] In this embodiment, based on step 4 in embodiment 2, the additive manufacturing technology used is selective laser melting (SLM).

[0091] In this embodiment, based on step five in embodiment two, the light alloy powder is an aluminum alloy (such as Al-12Si), and the particle size range of the powder used is 10 μm-55 μm.

[0092] In this embodiment, based on step six in embodiment two, the laser process parameters of the laser selection melting equipment are set, and the power is specifically 200W, the laser scanning speed is 750mm / s, the powder layer thickness is 50μm; and the scanning interval is 120μm.

[0093] In this embodiment, based on step six in embodiment two, when inert gas protection is introduced, the oxygen content is maintained at 100 ppm-1000 ppm during the laser selective melting process.

[0094] In this embodiment, based on step eight described in embodiment two, the temperature range of the stress annealing treatment of the SLM formed aluminum alloy is 240°C-260°C.

[0095] Compared with the prior art, the present invention has the following advantages:

[0096] The present invention utilizes the characteristics of laser selective melting process, which is fast, has little constraints, and can quickly form complex structures with high precision, to prepare bionic structures with complex structures that are difficult to form with traditional material processing techniques but have excellent innate comprehensive mechanical properties. It spans the two fields of additive manufacturing and bionics, drawing on the strengths of each to achieve the forming of components, thereby meeting potential industrial needs.

[0097] The metal components formed from titanium alloy in this invention solve the problems of spheroidization, cracking, deformation, warping, delamination, etc. existing in traditional material processing.

[0098] Titanium alloy powder has the characteristics of relatively cheap raw material price, high strength, light texture, good corrosion resistance, etc., and has good industrial application value.

[0099] By optimizing the laser process parameters of the laser selective melting equipment, the forming accuracy can reach ±50μm, the surface roughness is less than 50μm, and the density is not less than 99.9%. Thus, a bionic metal structure with dense organization, few defects and high comprehensive mechanical properties can be obtained; through subsequent wire cutting, cleaning, sandblasting and other treatments, the surface roughness can be reduced to less than 10μm, and a bionic structure with good surface quality can be obtained.

[0100] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0101] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A Bouligand spiral stacking structure, characterized in that: Including Bouligand spiral stacking matrix structure and honeycomb structure with gradient change; The Bouligand spiral stacking matrix structure comprises a plurality of single-layer elementary structures which are stacked in the same direction and rotated in the vertical direction at a preset angle in sequence; the single-layer elementary structure comprises a plurality of hollow cylindrical tubes which are closely arranged in the same direction; the preset angle range is 8 ∘ ⩽α⩽15 ∘ ; The honeycomb structure with gradient change is filled in each of the hollow cylindrical tubes; the honeycomb structure comprises a plurality of hollow structures of single honeycombs, and is filled and arranged along the axial direction of the hollow cylindrical tube; the center of the gradient change is the center of the bottom surface of the hollow cylindrical tube, and the hexagonal honeycombs with the same radius distance from the center have the same gradient rate and the same honeycomb wall thickness; each vertex of the outermost honeycomb structure is inscribed in the hollow cylindrical tube; The method of preparing the Bouligand spiral stacking structure by using a laser selective melting device includes: Light alloy powder is filled into the laser selective melting equipment and the laser process parameters are set; the laser process parameters include a power range of 100W-500W, a laser scanning speed range of 500mm / s-2000mm / s, a powder layer thickness of 20μm-50μm; a scanning interval of 70μm-120μm; an inert protective gas is introduced into the forming chamber, and the oxygen content is maintained at 100ppm-1000ppm during the laser selective melting process.

2. A method for preparing a Bouligand spiral stacking structure, characterized in that: include: Establishing a three-dimensional simulation model of the Bouligand spiral stacking structure according to claim 1; Performing two-dimensional processing on the three-dimensional simulation model to obtain two-dimensional slice data; The two-dimensional slice data is input into a laser selective melting device for calculation processing to obtain a motion trajectory of the printer; Performing printing preparation work in the laser selective melting device; The three-dimensional simulation model is printed according to the motion trajectory to obtain a Bouligand spiral stacking structure.

3. The method for preparing the Bouligand spiral stacking structure according to claim 2, characterized in that: The printing preparation work in the laser selective melting device specifically includes: Light alloy powder is filled into the laser selective melting device, laser process parameters are set, and inert gas is filled in.

4. The method for preparing the Bouligand spiral stacking structure according to claim 2, characterized in that: The three-dimensional simulation model is printed according to the motion trajectory to obtain a Bouligand spiral stacking structure, and then the method further includes: The Bouligand spiral stacking structure is subjected to wire cutting, stress relief annealing, cleaning and sandblasting.

5. The method for preparing the Bouligand spiral stacking structure according to claim 2, characterized in that: The three-dimensional simulation model of the Bouligand spiral stacking structure according to claim 1 is established, specifically comprising: A plurality of hollow cylindrical tubes are closely arranged in the same direction to form a single-layer elementary structure, and a simulation model of the single-layer elementary structure is obtained; The plurality of single-layer primitive structure simulation models are sequentially spirally stacked in a vertical direction at a preset angle to obtain a Bouligand spiral stacking matrix structure simulation model; Filling the Bouligand spiral stacking matrix structure simulation model with a honeycomb structure having a gradient change to obtain an initial simulation model of the Bouligand spiral stacking structure; The initial simulation model is repaired so that each vertex of the outermost honeycomb structure is inscribed in the hollow cylindrical tube, thereby obtaining a three-dimensional simulation model of the Bouligand spiral stacking structure.

6. The method for preparing the Bouligand spiral stacking structure according to claim 3, characterized in that: The light alloy powder is titanium alloy powder or aluminum alloy powder.

7. The method for preparing the Bouligand spiral stacking structure according to claim 3, characterized in that: The particle size of the light alloy powder is in the range of 10-55 μm.

Images