Telescopic member lightweight structure and composite manufacturing method

Abstract

The present application belongs to the field of material processing and manufacturing, and relates to the structural design and manufacturing of telescopic members. The present application adopts a "thin-walled panel + micro-truss + thin-walled panel" structure of the topological sandwich configuration of the side wall of a single sleeve, which can effectively improve the rigidity of the member, maximally reduce the weight of the member, and meet the load-carrying capacity and lightweight requirements of the member; the process of laser selective forming of a preform and then laser deposition of a preform to form a final single member can break through the size limitation of the forming equipment, and can maximally ensure the consistency of the overall organizational performance of the member, and realize high-quality manufacturing of large-size members.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of material processing and manufacturing, and relates to a telescopic member lightweight structure and a composite manufacturing method. BACKGROUND

[0002] High load bearing and high mobility have become the development direction of new vehicles, and the contradiction between the lightweight design of the load bearing structure and the high load bearing efficiency is increasingly prominent. Lightweight is the key to the structural design of new vehicles. Telescopic members are widely used in mobile vehicles, and are favored by engineers due to their light weight, high strength and flexible structure. The commonly used telescopic members at present are basically formed by machining and cutting. The side walls of the members formed by this method are generally solid structures. The solid structure has the problem of contradiction between rigidity and lightweight requirement. If rigidity is pursued, the wall thickness needs to be thickened, and the weight will also increase. If lightweight requirement is pursued, the quality is reduced, and the rigidity is also reduced. In recent years, with the increasing maturity of lightweight topological structure, its advantages of less material consumption and good structural stability have gradually emerged, and a large number of application verifications have been carried out in the engineering field, which have achieved good results. Topological optimization is the main design method in the conceptual design stage of the structure. The basic idea is to convert the optimal topology problem of the structure into the best layout problem of the material in the design area, so as to achieve the optimization goal. As a high-quality manufacturing method of new concept structure, additive manufacturing technology improves the designability of the structure of the member, and has considerable adaptability to the manufacturing of topological structure, and has been widely used in the engineering field, and also provides a new technical path for the manufacturing of complex members. However, additive manufacturing needs to be carried out in the box, and the size of the member formed at one time is limited, so the member needs to be mechanically connected after forming to meet the technical indicators of the final member. However, mechanical connection increases the quality of the member, which does not meet the development concept of lightweight. At the same time, the optimization path and method are different for different member structures and applications, therefore, it is important to optimize the means and the final structure form of the telescopic member, and the manufacturing means used for the optimized structure also needs further demonstration and application verification. SUMMARY

[0003] According to the contradiction between the load-bearing capacity of the component and the lightweight demand, the application takes the telescopic component as the object and provides a telescopic component lightweight structure and a composite manufacturing method. In the design end, the lightweight design idea is mainly used to optimize the structure of the telescopic component, and in the manufacturing end, the two-step manufacturing technology based on preforming and reconnection is mainly used to break the bottleneck that the large component is difficult to form due to the size limitation, the laser selective melting forming technology is selected to manufacture the prefabricated component, then the laser deposition forming method is used to connect the prefabricated component, and finally the assembly forming of the final component product is completed. The design and manufacturing technology involved in the application can effectively reduce the weight of the component while ensuring the rigidity of the component, break the contradiction between the load-bearing capacity of the component and the lightweight demand, liberate the design idea, and use the laser deposition forming method to connect the laser selective melting prefabricated component, so that the consistency of the organization and performance of the final component can be effectively ensured.

[0004] The technical means adopted by the application is as follows:

[0005] The telescopic component lightweight structure is a multi-section sleeve type thin-walled structure, the sleeve is positioned through the limiting block inside the side wall during the sleeve assembly forming process, the side wall of the single sleeve component adopts the sandwich structure formed by topology optimization, and the side wall secondary load-bearing area adopts the hollow topology structure, so as to achieve the purpose of reducing the weight of the whole component and realize the cooperation of the lightweight demand and the load-bearing capacity of the component; in the manufacturing process, the laser selective melting forming process is selected to manufacture the prefabricated component for the large single sleeve structure which exceeds the forming capacity of the equipment, and then the laser deposition forming process is used to connect the prefabricated component, so as to realize the final forming of the component.

[0006] The section sleeve type thin-walled structure refers to several hollow rectangular or square thin-walled components with different side lengths, which are combined into a sleeve assembly structure in the order of decreasing side length from outside to inside, and limiting blocks are installed inside the eight corners of the component except the smallest size sleeve, the limiting blocks are connected with the sleeve wall through bolts, and at the same time, step structures are integrally formed on the four corners outside the top of the sleeve except the largest sleeve, which are used to cooperate with the limiting blocks to control the extension amount of the sleeve;

[0007] The size of the single sleeve component should be at least 0.2mm gap on a single side in the middle section to ensure that the telescopic and retractable process in the middle section range does not produce jamming and interference phenomenon, except that the sleeve is tightly fitted within the range of not less than 50mm up and down;

[0008] The single sleeve component side wall topology sandwich structure is a structure of "thin-walled panel + micro-truss + thin-walled panel", and the middle layer lattice is preferably a body-centered cubic unit cell structure (regular hexagonal cross section);

[0009] The hollow topological structure of the secondary force area is a triangular configuration filled with a reticular grid, three corners of the triangle need to be rounded, which improves the stress concentration caused by sharp corners, can fully utilize the advantage of strong stability of the triangle to improve the rigidity of the component, and the reticular grid can effectively improve the stress behavior of the triangular hollow part and improve the load capacity of the overall component.

[0010] The composite manufacturing method of the telescopic component light-weight structure has the following steps:

[0011] The first step is to process the prefabricated component

[0012] The prefabricated component is segmented and formed according to the size of the production equipment, and the process separation surface is selected at the middle position of the component to leave a clamping space for the subsequent connection process, and the side wall on both sides of the process separation surface is replaced with a solid structure instead of a topological sandwich structure, in order to avoid damaging the integrity of the sleeve structure, and the process separation surface is preferably located at the middle position of the component while avoiding the triangular hollow feature;

[0013] The second step is to perform laser selective melting forming on the prefabricated component

[0014] The laser selective melting forming process of the prefabricated component needs to reserve a 0.5mm removal allowance on the surface of the subsequent matching area, and according to the most prominent feature of large-area hollow thin wall and micro-truss filling, the vertical direction to the substrate should be selected during forming to improve the forming accuracy of the main feature, reduce the support weight, and improve the printing speed;

[0015] The third step is to connect the prefabricated component by laser deposition forming

[0016] The laser deposition forming connection prefabricated component is to connect the prefabricated component completed by the laser selective melting process by designing the bevel specification and optimizing the connection sequence to realize the deformation control of the component connection process, and finally complete the connection of the prefabricated component;

[0017] The fourth step is to machine all internal and external profiles to remove the machining allowance, complete the manufacturing of the prefabricated body, and then perform assembly, and finally complete the manufacturing of the telescopic component.

[0018] The connecting bevel is designed as a V-shaped bevel or an X-shaped bevel, the bevel angle is 60°, and a 1mm blunt edge should be left at the bottom end of the bevel, the V-shaped bevel is opened when the wall thickness is less than 10mm, and the X-shaped bevel is opened when the wall thickness is greater than 10mm, which can inhibit the root unmelted and improve the thermal deformation during connection.

[0019] The connection sequence is opposite edge connection, multi-layer and multi-pass layer-by-layer filling, and finally the connection is completed.

[0020] The beneficial effects of the present application are:

[0021] (1) The single sleeve side wall topology sandwich configuration is "thin-walled panel + micro-truss + thin-walled panel", which can effectively improve the rigidity of the component, maximize the weight reduction of the component, and meet the component load capacity and lightweight requirements;

[0022] (2) The process of connecting the preform formed by laser selective forming to the final single component formed by laser deposition forming can break through the size limitation of the forming equipment, and can maximize the consistency of the overall organization performance of the component, realizing high-quality manufacturing of large-size components. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a schematic diagram of a telescopic lightweight component;

[0024] Figure 2 is a schematic diagram of a sleeve typical component;

[0025] Figure 3 is a schematic diagram of a preform separation surface;

[0026] Figure 4 is a schematic diagram of the preform laser selective forming swing;

[0027] Figure 5 is a schematic diagram of the preform connection groove;

[0028] Figure 6 is a schematic diagram of the connection sequence.

[0029] In the figure: 1 is sleeve A; 2 is sleeve B; 3 is sleeve C; 4 is a triangular hollow configuration; 5 is a limiting block; 6 is a step structure; 7 is a matching surface; 8 is a gradient transition zone; 9 is a preform separation surface; 10 is an inner wall; 11 is an outer wall; 12 is a body-centered cubic cell topology micro-truss structure; 13 is a base plate; 14 is a preform frame; 15 is a preform frame; 16 is a groove; 17 is a blunt edge. DETAILED DESCRIPTION

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0031] The telescopic lightweight component is mainly composed of three sleeves A1, B2 and C3, wherein the sleeve side wall is provided with a triangular hollow structure 4 with an inner built-in topology structure and an acute angle rounded corner, eight corners of the top and bottom of the single sleeve are provided with limiting blocks 5 fixed by bolts, the limiting blocks 5 are installed in the eight corners of the inside of the remaining sleeves except the smallest sleeve C3 by bolts, and the step structure 6 is integrally formed at the four corners of the top of the remaining sleeves except the largest sleeve A1, and the gradient transition zone 8 with a width larger than the size of the matching surface 7 by 0.2mm is made on the sleeve cavity wall, the preform separation surface 9 is selected in the middle of the sleeve component, the sleeve wall is composed of three parts of the inner wall 10, the outer wall 11 and the body-centered cubic unit cell topology micro-truss structure 12 between the two, which is a lightweight structure, and the 100mm range of the separation surface 9 is a solid structure for subsequent groove manufacturing;

[0032] When the laser selective melting forming of the preform of the telescopic lightweight component is manufactured, the forming substrate 13 is needed as the basis, and the preform frames 14 and 15 should be perpendicular to the surface of the substrate;

[0033] The laser selective melting forming process of the preform of AlSi10Mg material is that the laser power is 450W, the scanning speed is 1600mm / s, and the lap width is 0.15mm;

[0034] The completed preform is opened to the required groove 16 with the separation surface 9 as the reference, the groove angle is 60°, the blunt edge 17 with a height of 1mm is made at the bottom of the groove, the connection forming is divided into bottoming connection and filling connection, and the sequence of each process is as shown in Figure 6 ①→②→③→④→①→…, until the space of the straight surface groove is filled, the sleeve blank component is formed, the laser deposition forming connection process is that the laser power is 3000-3500W, the scanning speed is 10-15mm / s, the powder feeding speed is 5-15g / min, and the laser defocusing amount is 15mm;

[0035] Finally, the sleeve blank component is removed by mechanical machining method to complete the manufacture of the sleeve component.

Claims

1. A composite manufacturing method for a lightweight structure of a telescopic component, characterized in that, The lightweight structure of the telescopic component has an overall structure of a multi-sleeve thin-walled structure. During the assembly and forming of the sleeve, it is positioned by the limiting block on the inner side of the side wall. The side wall of the single sleeve component adopts topology optimization to form a sandwich structure, and the secondary load-bearing area of ​​the side wall adopts a hollow topology structure. The multi-sleeve thin-walled structure consists of several hollow rectangular or square thin-walled components with varying side lengths. These components are assembled into a set structure by combining the sleeves in descending order of side length from the outside to the inside. Except for the smallest sleeve, all other sleeves have limit blocks installed on the inner side of the eight apex corners of the component. The limit blocks are connected to the sleeve wall by bolts. Additionally, except for the largest sleeve, all other sleeves have stepped structures integrally formed on the outer side of the four apex corners of the top, which are used to cooperate with the limit blocks to control the extension amount of the sleeve. The single-sleeve component has a sidewall topological sandwich structure of "thin-walled panel + micro-truss + thin-walled panel", and the intermediate layer lattice is a body-centered cubic unit cell structure. The hollow topology of the secondary load-bearing area is a triangular configuration filled with a mesh grid, and the three corners of the triangle need to be rounded. The composite manufacturing method comprises the following steps: Step 1: Precast component processing The prefabricated components are formed in sections according to the size of the production equipment. Components that exceed the forming capacity of the laser selective forming equipment need to be formed in sections first. The process separation surface should be selected in the middle of the component, and the topological sandwich structure should be replaced with a solid structure on the side walls on both sides of the process separation surface to avoid the triangular hollow features. Step 2: Laser selective melting and shaping of precast components The laser selective melting forming process of the prefabricated component requires a 0.5 mm removal allowance to be reserved on the surface of the subsequent mating area. Furthermore, based on its most prominent feature of being a large-area hollow thin-walled structure filled with micro-trusses, it should be perpendicular to the substrate during forming. Step 3: Laser deposition forming and connecting prefabricated components The laser deposition forming connection prefabricated component is formed by designing the bevel specifications and optimizing the connection sequence of the prefabricated component after the laser selective melting process, thereby controlling the deformation during the component connection process and finally completing the connection of the prefabricated component; Step 4: Machining is performed on all internal and external surfaces to remove machining allowances, completing the manufacturing of the prefabricated body. Then, the parts are assembled to finally complete the manufacturing of the telescopic components.

2. The composite manufacturing method for the lightweight structure of the telescopic component according to claim 1, characterized in that, The dimensions of the single sleeve component should be such that, in addition to ensuring a tight fit within a range of no less than 50 mm at the upper and lower ends of the sleeve, a gap of at least 0.2 mm on each side is provided in the middle section.

3. The composite manufacturing method for the lightweight structure of the telescopic component according to claim 1, characterized in that, In the third step, the connecting bevel is designed as a V-shaped bevel or an X-shaped bevel with a bevel angle of 60°. A 1 mm blunt edge should be left at the bottom of the bevel. When the wall thickness is less than 10 mm, a V-shaped bevel is opened, and when the wall thickness is greater than 10 mm, an X-shaped bevel is opened.

4. The composite manufacturing method for the lightweight structure of the telescopic component according to claim 1, characterized in that, In the third step, the connection sequence is to connect opposite edges, fill multiple layers and channels one by one, and complete the final connection.

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