Additive manufacturing method of composite structure

Abstract

The invention discloses an additive manufacturing method of a composite structure, and belongs to the field of friction stir additive manufacturing, and the method comprises the following steps: moving a welding tool head of friction stir additive manufacturing equipment to a position where a base material needs to be subjected to additive manufacturing; the welding tool head is driven to rotate to drive the additive material in the welding tool head to rotate, and the surface of the welding tool head and / or the surface of the additive material and the additive surface of the base material are / is subjected to stirring friction; when the temperature of the additive part of the additive material reaches 50%-90% of the melting point of the additive material, the welding tool head is moved, so that a gap is formed between the welding tool head and the base material; pressure is continuously applied to the additive material in the direction close to the base material, so that the additive part of the additive material is deposited and attached to the base material, according to the method, the surface of the welding tool head and the surface of the additive material can be jointly subjected to stirring friction with the surface of the base material, the temperature rising speed is higher, the preheating time is shortened, and the welding efficiency is improved. And then the plasticized additive material is deposited and attached to the base material by continuously applying pressure to the additive material in the direction close to the base material, and additive manufacturing is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to an additive manufacturing method for a composite structure. Background Art

[0002] With the development of new energy vehicles, the requirements for on-board power systems are constantly increasing. The extensive use of copper alloys in the power system will cause new energy vehicles to be too heavy and costly. In order to achieve weight reduction and cost reduction, aluminum-copper composite structures are often used to ensure conductivity while reducing the amount of copper used, thereby reducing overall weight and cost.

[0003] Normally, aluminum-copper composite structures are processed by explosion welding, friction welding, rolling, etc. However, the above processing methods all have certain limitations, so they need to be improved. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an object of the present invention is to propose an additive manufacturing method for a composite structure, moving the welding head of a stir friction additive manufacturing equipment to a position where the substrate needs additives; driving the welding head to rotate to drive the additive material in the welding head to rotate, and stirring and rubbing the surface of the welding head and / or the surface of the additive material with the additive surface of the substrate; when the temperature of the additive part of the additive material reaches 50%-90% of the melting point of the additive material, moving the welding head so that there is a gap between the welding head and the substrate; and continuously applying pressure to the additive material in a direction close to the substrate to deposit the additive part of the additive material on the substrate.

[0006] According to the above technical means, the present invention can stir and rub the surface of the welding tool head and the surface of the additive material with the additive surface of the substrate, which will heat up faster and reduce the preheating time. Then, by continuously applying pressure to the additive material in the direction close to the substrate, the plasticized additive material is deposited and adhered to the substrate to achieve additive manufacturing.

[0007] Optionally, in one embodiment of the present invention, the additive material is in the shape of a rod.

[0008] Optionally, in one embodiment of the present invention, the shape of the additive material is rod-shaped; the gap in step S3 is H, satisfying: 0.05 mm ≤ H ≤ 10 mm.

[0009] Optionally, in one embodiment of the present invention, before step S2, step S10 is further included: performing surface roughening treatment on the additive surface.

[0010] Optionally, in one embodiment of the present invention, the surface of the additive material is roughened by a laser ablation process and / or an etching process.

[0011] Optionally, in one embodiment of the present invention, after the surface of the additive material is roughened, its surface roughness Ra is 0.05 μm≤Ra≤10 μm.

[0012] Optionally, in one embodiment of the present invention, the surface of the additive material is roughened to form a spiral groove structure.

[0013] Optionally, in one embodiment of the present invention, a stirring needle is provided on the welding tool head, and step S4 further comprises that the stirring needle penetrates into the substrate while the additive part of the additive material is deposited and adhered to the substrate.

[0014] Optionally, in one embodiment of the present invention, the material of the substrate is any one of aluminum, magnesium, copper, or any one of aluminum alloy, magnesium alloy, and copper alloy, and the material of the additive material is any one of aluminum, magnesium, copper, or any one of aluminum alloy, magnesium alloy, and copper alloy.

[0015] Beneficial effects of the embodiments of the present invention: The additive manufacturing method of the composite structure of the embodiments of the present invention, for the rod-shaped additive material, stirs and rubs the additive material and the welding head with the substrate together, so as to plasticize the additive part of the additive material more quickly, and then continuously applies pressure to the additive material in the direction close to the substrate to deposit the additive part on the surface of the substrate. Furthermore, the surface roughening treatment is performed on the additive surface of the substrate to enhance the roughness of the additive surface, thereby improving the bonding ability of the composite structure. Furthermore, a stirring needle can be provided, so that while enhancing the bonding ability of the composite structure, the bonding area of ​​the additive material and the substrate material can also be increased to reduce resistance and improve conductivity.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0018] Figure 1 A schematic diagram of the structure of a friction stir additive manufacturing device according to an embodiment of the present invention;

[0019] Figure 2 is a flow chart of an additive manufacturing method for a composite structure according to an embodiment of the present invention;

[0020] Figure 3 Schematic diagram of the substrate structure after texturing treatment according to a specific embodiment of the present invention.

[0021] Reference numerals:

[0022] A substrate 10;

[0023] Additive materials 20;

[0024] Welding tool head 30;

[0025] The groove structure 40. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0027] like Figure 1-Figure 3 As shown, the composite structure includes a substrate 10 and an additive material 20 attached to the substrate 10, wherein the substrate 10 material may be any one of aluminum, magnesium, copper, or any one of aluminum alloy, magnesium alloy, and copper alloy. The additive material 20 may be any one of aluminum, magnesium, copper, or any one of aluminum alloy, magnesium alloy, and copper alloy. Taking the case where the substrate 10 material is copper or copper alloy, and the additive material 20 is aluminum or aluminum alloy as an example, the aluminum-copper composite structure can reduce the amount of copper used while ensuring conductivity, thereby reducing the overall weight and overall cost.

[0028] In one embodiment of the present invention, for example, copper can be stamped into a copper sheet / copper plate, and then additive material 20 can be aluminum. This aluminum-copper composite structure can be manufactured by stir friction additive manufacturing, and the specific additive manufacturing method steps are as follows:

[0029] S1: moving the welding head 30 of the friction stir additive manufacturing equipment to the position where the substrate 10 needs to be added;

[0030] S2: driving the welding head 30 to rotate to drive the additive material 20 in the welding head 30 to rotate, stirring and rubbing the surface of the welding head 30 and / or the surface of the additive material 20 with the additive surface of the substrate 10;

[0031] S3: when the temperature of the additive portion of the additive material 20 reaches 50%-90% of the melting point of the additive material 20 , the welding head 30 is moved so that a gap exists between the welding head 30 and the substrate 10 ;

[0032] S4: continuously applying pressure to the additive material 20 in a direction close to the substrate 10 , so as to deposit the additive portion of the additive material 20 onto the substrate 10 .

[0033] Specifically, the welding tool head 30 has a containing space, and the containing space can contain the additive material 20. The melting point of the welding tool head 30 is higher than the melting point of the additive material 20. The additive material 20 is a rod-shaped structure, and the cross section of the rod is circular or other shapes. The welding tool head 30 can rotate, and the rotating welding tool head 30 can drive the additive material 20 to rotate at the same time. When adding material, the welding tool head 30 moves to the position where the substrate 10 needs to add material. Further, the welding tool head 30 rotates to drive the additive material 20 in the welding tool head 30 to rotate; then the surface of the welding tool head 30 and / or the surface of the additive material 20 are stirred and rubbed with the additive surface of the substrate 10. Whether the surface of the welding tool head 30 and the additive surface of the substrate 10 are stirred and rubbed, or the surface of the welding tool head 30 and the surface of the additive material 20 are stirred and rubbed together with the additive surface of the substrate 10, or the surface of the additive material 20 and the additive surface of the substrate 10 are stirred and rubbed, the temperature of the additive material 20 will rise after the friction heat is generated. The temperature of the portion of the rod-shaped additive material 20 close to the substrate 10, i.e., the additive portion, continues to rise. When it reaches 50%-90% of the melting point of the additive material 20, the welding head 30 is moved so that there is a certain gap between the welding head 30 and the substrate 10. The gap can be the thickness of each layer of additive. Specifically, the range H of the gap can be 0.05mm≤H≤10mm. It is worth noting that during the stirring and friction process of the above-mentioned additive material 20 and the substrate 10, the additive material 20 is subjected to continuous downward pressure, and heat can be generated only by the rotating stirring and friction of the rod-shaped additive material 20 and the substrate 10. When the surface of the welding head 30 and the surface of the additive material 20 are stirred and rubbed together with the additive surface of the substrate 10, the heating speed will be faster. Experiments show that the preheating time can be reduced from the original 5-10s to 0.5-3s.

[0034] Furthermore, in step S4, pressure is continuously applied to the additive material 20 in a direction close to the substrate 10. It can be understood that after pressure is continuously applied to the additive material 20 in a direction close to the substrate 10, the additive material 20 is extruded from the welding head 30, and the direction in which the additive material 20 moves is toward the substrate 10, so that the plasticized additive part of the additive material 20 can be deposited and adhered to the surface of the substrate 10.

[0035] Furthermore, the welding head 30 also moves relative to the substrate 10, for example, only the welding head 30 moves horizontally and the substrate 10 does not move, or only the substrate 10 moves horizontally and the welding head 30 does not move, so that the additive material 20 squeezed out of the welding head 30 is rotated and stirred and rubbed on the additive surface of the substrate 10 under continuous pressure, and the additive material 20 continues to be plasticized during the friction process, thereby achieving continuous deposition and adhesion of the plasticized additive part on the surface of the substrate 10.

[0036] In one embodiment of the present invention, before step S2, step S10 is further included: performing surface roughening treatment on the surface of the additive material.

[0037] That is, before the surface of the welding head 30 and / or the surface of the additive material 20 are stir-fried with the additive surface of the substrate 10, the additive surface of the substrate 10 is also roughened to improve the roughness of the additive surface. After the roughening treatment, the surface roughness Ra of the additive surface is 0.05μm≤Ra≤10μm. In one embodiment, the additive surface can be treated by laser ablation, etching, etc. to increase the bonding ability between the additive material 20 and the substrate 10, that is, the bonding ability of the composite structure can be enhanced. Experiments show that when the surface of the substrate 10 is not treated, its tensile strength is 5000N. After the surface of the substrate 10 is treated to increase the surface roughness, it can reach 12000N.

[0038] In one embodiment of the present invention, the surface of the additive material can be roughened into a spiral structure, for example, laser ablated or etched into a spiral groove structure 40. Such a groove structure 40 can further increase the bonding ability between the additive material 20 and the substrate 10.

[0039] In one embodiment of the present invention, a stirring needle may be provided on the welding head 30, and the stirring needle is arranged on the bottom surface of the welding head 30. The stirring needle may be inserted into the substrate 10, and during the rotation of the welding head 30 and the stirring friction between the stirring needle and the substrate 10, at least a part of the substrate 10 material may be lifted up and then mixed with the additive material 20, thereby increasing the bonding area between the additive material 20 and the substrate 10 material. Taking the aluminum-copper composite structure as an example, during the rotation of the welding head 30, the stirring needle inserted into the substrate 10 lifts the copper of the substrate 10, and then a part of the copper will be mixed with the aluminum of the additive material 20 to increase the bonding area, thereby improving the conductivity and the bonding performance of the two. Experiments show that the resistance of the composite structure formed by the above process steps can be reduced from 0.0175 ohms to 0.008 ohms, and the resistance is reduced by half, and the conductivity will also be increased accordingly.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0041] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0042] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for additive manufacturing of a composite structure, characterized in that: Includes steps: S1: Move the welding head of the friction stir additive manufacturing equipment to the position where the substrate needs to be added; S2: driving the welding tool head to rotate and driving the additive material in the welding tool head to rotate, so as to stir and rub the surface of the welding tool head and / or the surface of the additive material with the additive surface of the substrate; S3: When the temperature of the additive portion of the additive material reaches 50%-90% of the melting point of the additive material, the welding tool head is moved so that there is a gap between the welding tool head and the substrate; S4: Continuously applying pressure to the additive material in a direction close to the substrate to deposit the additive portion of the additive material onto the substrate.

2. The additive manufacturing method according to claim 1, characterized in that: The additive material is in the shape of a rod.

3. The additive manufacturing method according to claim 1, characterized in that the gap H in step S3 satisfies: 0.05mm≤H≤10mm.

4. The additive manufacturing method according to claim 1, characterized in that: Before step S2, the method further includes step S10: performing surface roughening treatment on the surface of the additive material.

5. The additive manufacturing method according to claim 4, characterized in that: The surface of the additive material is roughened by laser ablation and / or etching.

6. The additive manufacturing method according to claim 4, characterized in that: After the additive manufacturing surface is roughened, its surface roughness Ra is 0.05μm≤Ra≤10μm.

7. The additive manufacturing method according to claim 4, characterized in that: After the surface of the additive is roughened, a spiral groove structure is formed.

8. The additive manufacturing method according to claim 1, characterized in that: A stirring needle is provided on the welding tool head, and step S4 also includes that the stirring needle penetrates into the substrate while the additive material additive part is deposited and adhered to the substrate.

9. The additive manufacturing method according to any one of claims 1 to 8, characterized in that: The material of the substrate is any one of aluminum, magnesium, and copper, or any one of an aluminum alloy, a magnesium alloy, and a copper alloy.

10. The additive manufacturing method according to any one of claims 1 to 8, characterized in that: The material of the additive material is any one of aluminum, magnesium, copper, or any one of aluminum alloy, magnesium alloy, and copper alloy.

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