Ultra-light satellite-borne reflector based on metal 3D printing

Abstract

The invention discloses an ultra-light satellite-borne reflector based on metal 3D printing, and relates to the field of metal 3D printing, the ultra-light satellite-borne reflector comprises a reflector surface, a lattice structure, a bottom plate and a flexible joint, the lattice structure is connected with the reflector surface and the bottom plate, and the reflector surface, the lattice structure and the bottom plate form a sandwich structure. One end of the flexible joint is connected with the bottom plate, and the other end of the flexible joint provides an external interface through a threaded hole or a through hole. An existing reflector design thought is broken through, the reflector surface, the dot matrix sandwich, the bottom plate and the flexible joint of the reflector are integrated into one part, integrated design and optimization are achieved, the number of the parts is reduced by 80% or above, the total weight of the reflector is reduced by 20% or above, the assembling link of the flexible joint and other structures is eliminated in the reflector manufacturing process, the reflector is integrally manufactured through 3D printing, and the manufacturing cost is reduced. And the manufacturing cost and time are greatly saved, and important application value is achieved.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing technology, and particularly to an ultra-lightweight spaceborne mirror based on metal 3D printing. Background Art

[0002] The mirror assembly is the core component of the spaceborne optical system for imaging, which determines the imaging performance of the entire spaceborne optical system. The design of the mirror assembly needs to comprehensively consider the weight of the mirror assembly and its surface shape accuracy under static conditions such as gravity loading, temperature change, and assembly error, as well as the structural stiffness and stability under dynamic conditions such as sinusoidal shock and random response during the rocket launch stage, which poses extremely high requirements on the design method. Currently, large spaceborne mirror assemblies usually consist of parts such as a mirror body, a cone sleeve, a flexible joint, and a substrate. The number of parts can be dozens, the types of materials used are many, and various processing technologies are included. Its precision manufacturing and assembly processes are cumbersome, and the R & D and production cycles are extremely long.

[0003] After investigation, the metal 3D printing technology can achieve high-performance design and efficient manufacturing of the mirror, reduce the structural weight, reduce the processing and assembly processes, effectively improve the performance of the mirror, and reduce the R & D and manufacturing cycles. However, the existing design configurations of the mirror body based on metal 3D printing are mainly the composite structure of the mirror surface and the reinforcing ribs, and this configuration still has the following limitations: (1) This mirror body structure does not contain flexible structures such as flexible joints and cannot absorb gravity, heat, and vibration deformation. It is necessary to additionally manufacture flexible structures and assemble them with the mirror body, resulting in a significant increase in structural weight and manufacturing time; (2) This mirror body structure has no bottom plate, and the structural stiffness is insufficient. For example, the stiffness is lower than that of the sandwich structure of the mirror surface - lattice - bottom plate. In addition, currently, the 3D printing direction of the lattice sandwich structure must be along the in-plane direction to ensure successful printing, with a large number of printing layers and a long time consumption.

[0004] Therefore, the technical personnel in this field are committed to developing an ultra-lightweight spaceborne mirror based on metal 3D printing. This new design scheme of 3D printed ultra-lightweight and multi-part integrated mirror reduces the weight of the mirror, improves the surface shape accuracy, reduces the number of parts, reduces the manufacturing and assembly processes, and reduces the manufacturing cost and time. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is the technical problems of a significant increase in structural weight and manufacturing time, insufficient structural stiffness, and long time consumption caused by the fact that the existing design of the mirror body based on metal 3D printing does not contain flexible structures such as flexible joints.

[0006] To achieve the above object, the present invention provides an ultra-lightweight spaceborne mirror based on metal 3D printing, which includes a mirror, a lattice structure, a bottom plate and a flexure joint. Among them, the lattice structure connects the mirror and the bottom plate, and the mirror, the lattice structure and the bottom plate form a sandwich structure, so that the ultra-lightweight spaceborne mirror has high stiffness. One end of the flexure joint is connected to the bottom plate, and the other end provides an external interface through a threaded hole or a through hole.

[0007] Further, the mirror is spherical and has the function of reflecting visible light.

[0008] Further, the lattice structure is a porous structure and has functions of load bearing, weight reduction and shock absorption. The configurations of the lattice structure include truss, minimal surface, and open-cell plate lattice structure. The purpose of opening holes is that after the mirror is manufactured by selective laser melting (SLM), the unfused powder can be discharged through the holes.

[0009] Further, the wall thickness of the lattice structure gradually increases from 3 to 5 mm below the mirror to the mirror. The relative density gradient of this part of the lattice structure changes by 95%. During the SLM manufacturing process, it can effectively support the mirror and prevent the generation of collapse and crack defects.

[0010] Further, the bottom plate is a planar structure and has functions of load bearing and support, and at the same time connects the lattice structure and the flexure joint.

[0011] Further, the flexure joint includes a zigzag flexible structure, which functions to absorb deformations caused by heat, assembly, gravity and vibration, and ensure the surface shape accuracy of the mirror. The number of flexure joints is 3 or 6.

[0012] Further, by optimizing the mirror thickness, bottom plate thickness, lattice structure configuration, relative density, zigzag configuration, number of layers, single-layer thickness, thickness and width parameters of the flexure joint, it is ensured that under thermal, assembly, gravity and vibration deformations, the surface shape accuracy of the mirror and the fundamental frequency of the mirror meet the design requirements, where the mirror thickness is 1 to 5 mm and the bottom plate thickness is 1 to 5 mm.

[0013] Further, the ultra-lightweight spaceborne mirror based on metal 3D printing is an aluminum alloy structural part. The blank of the mirror is manufactured by the SLM process. The 3D printing direction is from the bottom plate to the mirror. The lattice structure and the mirror do not require support during the printing process.

[0014] Further, the lattice structure is one of IWP minimal surface, P-type minimal surface, G-type minimal surface, open-cell plate lattice structure or truss lattice structure. The relative density of the lattice structure increases linearly or along a quadratic function from the bottom plate to the mirror. The average relative density of the lattice structure is 5% to 50%.

[0015] Furthermore, each of the flexible joints contains 1 to 4 sets of "zigzag" structures. The number of layers of the "zigzag" structure is 2 to 6 layers, the thickness of a single layer is 0.9 to 1.2 mm, the total thickness is 5 to 20 mm, and the total width is 10 to 30 mm. The "zigzag" feature of the flexible joint is manufactured by 3D printing and wire cutting.

[0016] In the present invention, an integrated mirror design is proposed. The mirror surface, lattice sandwich core, bottom plate, and flexible joints are integrated into one part, and the mirror is manufactured by 3D printing. Integrating multiple parts into one part, lightweight is achieved through structural optimization, and the surface shape accuracy under gravity, heat, and vibration conditions is ensured. Integrated manufacturing is realized through 3D printing. Through the design of the sandwich structure of the mirror surface - lattice sandwich core - bottom plate of the integrated mirror, the structural stiffness is improved. Under the same weight, the sectional bending and torsional stiffness of the mirror surface - lattice sandwich core - bottom plate sandwich structure is higher than that of the mirror surface - stiffening rib structure. In this design, the wall thickness and relative density of the lattice sandwich core structure gradually increase along the bottom plate - mirror surface direction, enabling the mirror to be 3D printed along the out-of-plane direction. The wall thickness and relative density of the lattice sandwich core structure gradually increase along the bottom plate - mirror surface direction. The lattice structure serves as the support for the mirror surface structure, enabling the mirror to be successfully 3D printed along the out-of-plane direction without defects such as collapse and cracks.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] 1. Through the integrated design, the weight of the mirror is reduced, the surface shape accuracy is improved, the number of parts is reduced, the manufacturing and assembly processes are reduced, and the manufacturing cost and time are reduced.

[0019] 2. Under the condition of the same stiffness, this design can reduce the structural weight. Under the same weight, the stiffness of the mirror surface - lattice sandwich core - bottom plate sandwich structure is higher.

[0020] 3. Compared with the current 3D printing direction of the lattice sandwich core sandwich structure that must be along the in-plane direction, the 3D printing along the out-of-plane direction in the present invention can significantly reduce the printing time.

[0021] The present invention breaks through the existing mirror design concept, integrates the mirror surface, lattice sandwich core, bottom plate, and flexible joints of the mirror into one part, with integrated design and optimization. The number of parts is reduced by more than 80%, the total weight of the mirror is reduced by more than 20%. The assembly link of structures such as flexible joints is eliminated during the manufacturing process of the mirror. The mirror is integrally manufactured by 3D printing, greatly saving manufacturing cost and time, and has important application value.

[0022] The following will further illustrate the concept, specific structure, and technical effects generated by the present invention in conjunction with the drawings to fully understand the purpose, features, and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of a mirror with an IWP - type minimal surface lattice structure, which is a preferred embodiment of the present invention;

[0024] Figure 2 is a schematic diagram of a mirror with a P - type minimal surface lattice structure, which is a preferred embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of a mirror with an open - hole flat lattice structure, which is a preferred embodiment of the present invention;

[0026] Figure 4 is a schematic diagram of a mirror with a truss lattice structure and an enlarged view of a flexible joint, which is a preferred embodiment of the present invention;

[0027] Figure 5 is a schematic diagram of a mirror with a P - type minimal surface lattice structure and 6 flexible joints, which is a preferred embodiment of the present invention;

[0028] Figure 6 is a schematic diagram of a mirror with a G - type minimal surface lattice structure, which is a preferred embodiment of the present invention;

[0029] Figure 7 is a schematic diagram of a mirror with a G - type minimal surface lattice structure distributed along a circumference, which is a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following introduces multiple preferred embodiments of the present invention with reference to the accompanying drawings of the specification to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0031] In the drawings, components with the same structure are denoted by the same reference numerals, and components with similar structures or functions are denoted by similar reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. To make the illustration clearer, the thickness of some components in the drawings is appropriately exaggerated.

[0032] Embodiment 1

[0033] As Figure 1As shown in the figure, it is a schematic diagram of a mirror with an IWP-type minimal surface lattice structure. The mirror surface, lattice structure, and bottom plate form a sandwich structure, enabling the ultra-lightweight spaceborne mirror to have high stiffness. One end of the flexible joint is connected to the bottom plate, and the other end provides an external interface through threaded holes or through holes. The lattice structure is an IWP minimal surface, the average relative density of the lattice structure is 10%, the relative density of the lattice structure linearly increases from the bottom plate to the mirror surface, the thickness of the mirror surface is 1 mm, and the thickness of the bottom plate is 1 mm. There are 3 flexible joints, each flexible joint contains a set of zigzag structures, the number of layers is 4, the single-layer thickness is 0.9 mm, the total thickness is 7 mm, the total width is 30 mm, and the schematic diagram of the mirror is as shown in Figure 1 . The AlSi10Mg aluminum alloy mirror blank is manufactured by SLM, and the zigzag features of the flexible joints are manufactured by 3D printing and wire cutting.

[0034] Example 2

[0035] As shown in Figure 2 the figure, it is a schematic diagram of a mirror with a P-type minimal surface lattice structure. The average relative density of the lattice structure is 15%, the relative density of the lattice structure linearly increases from the bottom plate to the mirror surface, the thickness of the mirror surface is 5 mm, and the thickness of the bottom plate is 5 mm. There are 3 flexible joints, each flexible joint contains a set of zigzag structures, the number of layers is 4, the single-layer thickness is 0.9 mm, the total thickness is 7 mm, the total width is 24 mm, and the mirror design is as shown in Figure 3 . The AlSi10Mg aluminum alloy mirror blank is manufactured by SLM, and the zigzag features of the flexible joints are manufactured by 3D printing and wire cutting.

[0036] Example 3

[0037] As shown in Figure 3 the figure, it is a schematic diagram of a mirror with an open-cell flat lattice structure. The average relative density of the lattice structure is 5%, the relative density of the lattice structure linearly increases from the bottom plate to the mirror surface, there are 3 flexible joints, each flexible joint contains a set of zigzag structures, the number of layers is 6, the single-layer thickness is 1.0 mm, the total thickness is 15 mm, and the total width is 10 mm.

[0038] Example 4

[0039] As shown in Figure 4 the figure, it is a schematic diagram of a mirror with a truss lattice structure and an enlarged view of the flexible joint part. The average relative density of the lattice structure is 5%, the relative density of the lattice structure linearly increases from the bottom plate to the mirror surface, there are 3 flexible joints, each flexible joint contains four sets of zigzag structures, the number of layers of each set of zigzag structures is 2, the single-layer thickness is 0.9 mm, the thicknesses of the four sets of zigzag structures are the same in pairs, which are 11 mm and 3 mm respectively, and the total width is 10 mm.

[0040] Example 5

[0041] As Figure 5 shown, it is a schematic diagram of a mirror with a dot matrix structure of a P-type minimal surface. The average relative density of the dot matrix structure is 20%, the relative density of the dot matrix structure increases along a square function from the bottom plate to the mirror surface, there are 6 flexible joints, each flexible joint contains a set of zigzag structures, the number of layers is 2, the single-layer thickness is 1.2 mm, the total thickness is 9 mm, and the total width is 30 mm.

[0042] Example 6

[0043] As Figure 6 shown, it is a schematic diagram of a mirror with a dot matrix structure of a G-type minimal surface. The average relative density of the dot matrix structure is 30%, the relative density of the dot matrix structure increases linearly from the bottom plate to the mirror surface, there are 3 flexible joints, each flexible joint contains a set of zigzag structures, the number of layers is 6, the single-layer thickness is 1.0 mm, the total thickness is 7 mm, and the total width is 24 mm.

[0044] Example 7

[0045] As Figure 7 shown, it is a schematic diagram of a mirror with a dot matrix structure of a circumferentially distributed G-type minimal surface. Figure 7 It is a sectional view of a mirror with a dot matrix structure of a G-type minimal surface. The dot matrix structure is circumferentially distributed, the average relative density is 50%, the relative density of the dot matrix structure increases linearly from the bottom plate to the mirror surface, there are 3 flexible joints, each flexible joint contains a set of zigzag structures, the number of layers is 6, the single-layer thickness is 1.0 mm, the total thickness is 7 mm, and the total width is 24 mm.

[0046] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations according to the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. An ultra-lightweight satellite reflector based on metal 3D printing, characterized in that: The reflector comprises a mirror surface, a lattice structure, a base plate and a flexible joint, wherein the lattice structure connects the mirror surface and the base plate, and the mirror surface, the lattice structure and the base plate form a sandwich structure, so that the ultra-lightweight satellite-borne reflector has high rigidity, one end of the flexible joint is connected to the base plate, and the other end provides an external interface through a threaded hole or a through hole.

2. The ultra-lightweight satellite-borne reflector based on metal 3D printing according to claim 1, characterized in that: The mirror surface is a spherical surface and has the function of reflecting visible light.

3. The ultra-lightweight satellite-borne reflector based on metal 3D printing according to claim 1, characterized in that: The lattice structure is a porous structure with load-bearing, weight-reducing and shock-absorbing functions. The configuration of the lattice structure includes a truss, a minimal curved surface, and a perforated flat plate lattice structure. The purpose of the perforations is to allow unmelted powder to be discharged through the perforations after the reflector is manufactured by selective laser melting (SLM).

4. The ultra-lightweight satellite-borne reflector based on metal 3D printing according to claim 3, characterized in that: The wall thickness of the lattice structure gradually increases from 3 to 5 mm below the mirror surface to the mirror surface, and the relative density gradient of the lattice structure in this part changes to 95%, which can effectively support the mirror surface during the SLM manufacturing process to prevent collapse and crack defects.

5. The ultra-lightweight satellite-borne reflector based on metal 3D printing according to claim 1, characterized in that: The bottom plate is a planar structure, has a bearing and supporting function, and simultaneously connects the lattice structure and the flexible joint.

6. The ultra-lightweight satellite reflector based on metal 3D printing according to claim 1, characterized in that: The flexible joint includes a zigzag flexible structure, which is used to absorb deformation caused by heat, assembly, gravity, and vibration to ensure the surface accuracy of the mirror. The number of the flexible joints is 3 or 6.

7. The ultra-lightweight satellite-borne reflector based on metal 3D printing according to claim 1, characterized in that: By optimizing the mirror thickness, base plate thickness, lattice structure configuration, relative density, flexible "Z"-shaped configuration, number of layers, single layer thickness, thickness, and width parameters, it is ensured that the mirror surface accuracy and the fundamental frequency of the mirror meet the design requirements under the conditions of heat, assembly, gravity, and vibration deformation. The mirror thickness is 1 to 5 mm and the base plate thickness is 1 to 5 mm.

8. The ultra-lightweight satellite-borne reflector based on metal 3D printing according to claim 1, characterized in that: The ultra-lightweight satellite-borne reflector based on metal 3D printing is an aluminum alloy structural part. The mirror blank of the mirror is manufactured by SLM process. The direction of 3D printing is from the base plate to the mirror. The lattice structure and the mirror do not need to be supported during the printing process.

9. The ultra-lightweight satellite-borne reflector based on metal 3D printing according to claim 1, characterized in that: The lattice structure is one of an IWP minimal surface, a P-type minimal surface, a G-type minimal surface, an open-hole flat plate lattice structure or a truss lattice structure. The relative density of the lattice structure increases linearly or along a square function from the base plate to the mirror surface, and the average relative density of the lattice structure is 5% to 50%.

10. The ultra-lightweight satellite-borne reflector based on metal 3D printing according to claim 1, characterized in that: Each of the flexible joints contains 1 to 4 groups of zigzag structures, the number of layers of the zigzag structures is 2 to 6, the thickness of a single layer is 0.9 to 1.2 mm, the total thickness is 5 to 20 mm, and the total width is 10 to 30 mm. The zigzag features of the flexible joints are manufactured by 3D printing and wire cutting.

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