Self-supporting friction stir additive manufacturing device and manufacturing method

Abstract

The present invention relates to the field of stir friction additive technology, and specifically to a self-supporting stir friction additive manufacturing device and manufacturing method, comprising: a stirring head, the stirring head is used to thermally plasticize deposition materials; a stationary shoulder, the interior of the stationary shoulder is provided with a accommodating space for constraining deposition materials, the end of the stirring end of the stirring head is flush with the end of the stationary shoulder; a support body, the support body is connected to the stirring head, the support body is arranged at the end of the stirring end of the stirring head, the support body is provided with a support surface for providing support for the deposition material on the side close to the stirring head, and the opening of the end of the stationary shoulder is opposite to the support surface. The advantage of the device over the existing technology is that the device can be carried out without a support surface, only requires a starting point, and the subsequent additive process can be carried out without a support surface, realizing unsupported additive, abandoning the disadvantage that traditional additive must rely on a support surface as a base, making the additive method more flexible and the application scenario more extensive.

Description

Technical Field

[0001] The present invention relates to the field of friction stir additive manufacturing technology, and in particular to a self-supporting friction stir additive manufacturing device and a manufacturing method. Background Art

[0002] Friction stir additive manufacturing (FSAM) is a 3D printing technology developed based on the principles of friction stir welding. It uses the friction between the stirring needle and the connector to generate heat, softening the material at the joint, and then uses axial pressure to connect the materials. Compared to traditional 3D printing, this technology does not require a high-energy heat source or gas shielding, reducing manufacturing costs and improving production efficiency. Because the metal does not melt or solidify during the forming process, metallurgical defects such as thermal cracks and pores associated with melting are not generated, improving manufacturing quality. Friction stir additive manufacturing also has the advantages of high precision, low cost, and environmental friendliness.

[0003] Traditional friction stir additive devices require a substrate as a support surface. The material to be added is thermoplastically deposited onto the substrate through the friction stirring of a stirrer. The friction stirring process also mixes the additive material with the substrate material, achieving simultaneous mixing of the two materials while adding the material. However, existing friction stir additive devices lack a support surface without a substrate, rendering the material to be added unable to deposit and thus failing to achieve the additive function. Summary of the Invention

[0004] The purpose of the present invention is to address the shortcomings of the existing technology and provide a self-supporting stir friction additive manufacturing device and manufacturing method, which solves the problem in the existing technology that additive manufacturing cannot be performed without a substrate.

[0005] To achieve the above objectives, the present invention provides a self-supporting friction stir additive manufacturing device, comprising: a stirring head, the stirring head being used to thermoplasticize a deposition material; a stationary shoulder, the stationary shoulder having an interior space for containing the thermoplastic material, the end of the stirring end of the stirring head being flush with the end of the stationary shoulder; and a support body, the support body being connected to the stirring head and disposed at the end of the stirring end of the stirring head, the support body having a support surface for supporting the deposition material provided on a side of the support body close to the stirring head, the opening at the end of the stationary shoulder facing the support surface.

[0006] The advantage of the self-supporting friction stir additive manufacturing device over the existing technology is that the device can be carried out without a supporting surface and only requires a starting point. Subsequent additive processes can be carried out without a supporting surface, realizing unsupported additive manufacturing and eliminating the disadvantage that traditional additive manufacturing must rely on a supporting surface as a base, making the additive method more flexible and the application scenarios wider.

[0007] In some embodiments, the support surface is a circular surface, and the center of the support surface is concave to form a circular surface with a sunken center.

[0008] In some embodiments, the stirring head is connected to the support body through a stirring needle. The stirring head is a frustum structure, and the stirring needle is arranged at the center of the bottom surface of the stirring head and the support surface.

[0009] In some embodiments, the support body is a conical structure, the support surface is located on the top surface of the support body, and the center of the support surface is sunken and concave.

[0010] In some embodiments, the stationary shoulder is a conical structure, and the inner wall of the stationary shoulder is a conical structure.

[0011] In some embodiments, the diameter of the support surface is larger than the diameter of the stationary shoulder end.

[0012] In some embodiments, the outer wall of the stirring head is provided with a thread, and the stationary shoulder is provided with a feed hole, and the feed hole is opposite to the thread.

[0013] In some embodiments, the stirring head includes: a clamping end, a mating portion and a conical screw, the clamping end is connected to a power source for transmitting power for rotating the conical screw, the two ends of the mating portion are respectively connected to the clamping end and the conical screw, the mating portion is connected to the inner wall of the stationary shoulder for limiting the conical screw, the outer wall of the conical screw is provided with a thread, and a space for accommodating additive material is provided between the conical screw and the inner wall of the stationary shoulder.

[0014] In some embodiments, the distance between the support body and the end face of the stirring head is 0.2 mm-5 mm.

[0015] The present invention also proposes a self-supporting stir friction additive manufacturing method, including: S1: the stirring head rotates at high speed and penetrates into the substrate from the side of the substrate; S2: the raw material is fed into the gap between the stationary shaft shoulder and the stirring head for stirring and friction, and the stirring head shears the raw material into particles and transmits it downward; S3: through the friction and severe plastic deformation between the stirring head and the substrate, the raw material is thermoplastically deposited to form an additive layer, and then the stirring head separates from the substrate and performs spatial three-dimensional additive manufacturing along a preset path.

[0016] The advantages of the self-supporting friction stir additive manufacturing device described above over the prior art are the same as those of the prior art and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0018] Figure 1 is a schematic structural diagram of a device according to an embodiment of the present invention;

[0019] Figure 2 1 is a schematic structural diagram of a stirring head according to an embodiment of the present invention;

[0020] Figure 3 2 is a schematic structural diagram of a stationary shoulder according to an embodiment of the present invention.

[0021] Reference numerals:

[0022] Substrate 10; three-dimensional thin-walled part 20; self-supporting stirring head 30; clamping end 301; tapered screw 302; stirring needle 303; concave shoulder 304; support body 305; mating portion 306; stationary shoulder 40; locking end 401; feed hole 402; tapered inner wall 403. DETAILED DESCRIPTION

[0023] The following describes embodiments of the present invention in detail. Examples of the embodiments 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 only to explain the present invention and are not to be construed as limiting the present invention.

[0024] Friction stir additive manufacturing (FSAM) is a 3D printing technology developed based on the principles of friction stir welding. It uses friction between a stirring pin and a connecting piece to generate heat, softening the material at the joint. Axial pressure then bonds the materials together. This process eliminates the melting and solidification of the metal, thus reducing metallurgical defects such as thermal cracking and porosity associated with melting. In traditional FSM, a stirring tip is placed on a substrate. Friction between the two deposits the thermoplastic material onto the substrate, forming a deposited layer. In this process, the substrate primarily provides support, friction, and serves as a component of the material. During the FSM process, the substrate rubs against the stirring tip to soften the additive material, providing both support and friction. Furthermore, the substrate is partially softened during friction and mixes with the additive material during the stirring process, becoming a component of the additive material. In other words, the substrate is an essential component of traditional FSM; without a substrate, a FSM device cannot be used.

[0025] Reference below Figure 1-3 A self-supporting friction stir additive manufacturing device according to an embodiment of the present invention is described, comprising a self-supporting stirring head 30, a stationary shoulder 40, and a support body 305. The self-supporting stirring head 30 is used to thermoplasticize the deposition material. The stationary shoulder 40 has an internal space for containing the thermoplastic material. The end of the stirring end of the self-supporting stirring head 30 is flush with the end of the stationary shoulder 40. The support body 305 is connected to the self-supporting stirring head 30 and is disposed at the end of the stirring end of the self-supporting stirring head 30. The support body 305 has a support surface for supporting the deposition material on the side of the support body 305 near the self-supporting stirring head 30. The opening at the end of the stationary shoulder 40 faces the support surface. Compared to conventional friction stir additive devices, the self-supporting stirring head 30 of the present application has a new support body 305. The support surface of the support body 305 can replace the support function of the substrate 10. When the additive material extends from the discharge end at the bottom of the stationary shoulder 40, it rubs against the support surface of the support body 305, softening the additive material and thus achieving the coating of the additive material. Without the substrate 10 as support, the self-supporting stirring head 30 also requires a base point as a starting point. Once the additive material is softened, the softened additive material is brought into contact with the starting point, where it solidifies to form a starting point. The self-supporting stirring head 30 can then be raised, and the additive material will use this starting point as support to form a three-dimensional thin-walled part 20. Apart from the initial starting point, the remaining additive material does not require the participation of the substrate 10, thus achieving substrate-free self-supporting friction stir additive manufacturing.

[0026] The self-supporting friction stir additive device of the present invention can be used without a supporting surface, only requiring a starting point. Subsequent additive processes can be carried out without a supporting surface, thus achieving unsupported additive, eliminating the drawback that traditional additives must rely on a supporting surface as a base, making the additive method more flexible and the application scenarios more extensive. On the one hand, the device is free from the constraints of the substrate 10, making the device application scenarios more diverse. On the other hand, the device is also free from the constraints of the additive material structure. By simply lifting and moving the self-supporting stirring head 30 along a specific path, the additive material can be manufactured into additives of corresponding shapes according to needs or the manufacturer's wishes.

[0027] As one embodiment of the present invention, the support surface of the support body 305 is a circular surface, with the center of the support surface being concave, forming a circular surface with a sunken center. This forms a concave shoulder 304 of the support body 305. To gather the softened material, the support surface of the support body 305 has a concave structure, which can gather the softened additive material in the center and prevent it from being thrown out by the centrifugal force of rotation.

[0028] As one embodiment of the present invention, the diameter of the support surface of support body 305 is larger than the diameter of the end of stationary shoulder 40. After entering stationary shoulder 40, the additive material moves downward along the screw, being continuously extruded by the screw and falling into the concave shoulder 304 of support body 305. Because the diameter of the support surface of support body 305 is larger than the diameter of the end of stationary shoulder 40, the concave shoulder 304 of support body 305 can gather all the extruded additive material, ensuring a dense deposited layer.

[0029] The diameter and the concave angle of the concave shoulder 304 are not limited. Optionally, the diameter of the concave shoulder 304 is 10-30 mm, and the concave angle is 0-60 degrees.

[0030] As one embodiment of the present invention, the distance between the support surface of support body 305 and the end of stationary shoulder 40 is adjustable. The thickness of the deposited layer is determined by the distance between the support surface of support body 305 and the end of stationary shoulder 40. The support surface of support body 305 can be adjusted as needed to control the distance between the support surface of support body 305 and the end of stationary shoulder 40, thereby controlling the thickness of the deposited layer. Optionally, the distance between the support surface of support body 305 and the end of stationary shoulder 40 is 0.2 mm to 5 mm.

[0031] As one embodiment of the present invention, the self-supporting stirring head 30 has a truncated cone structure, and the stirring pin 303 is located at the center of the circle between the bottom surface and the supporting surface of the self-supporting stirring head 30. The stirring pin 303 serves as a connection. The length of the stirring pin 303 determines the distance between the supporting surface of the support body 305 and the end face of the self-supporting stirring head 30. The thickness of the deposited layer can be controlled by adjusting the length of the stirring pin 303.

[0032] As one embodiment of the present invention, support body 305 has a conical structure, with a support surface located on the top surface of support body 305, and a concave center of the support surface. Support body 305 may also have a cylindrical structure, which is not limited here. Preferably, this embodiment adopts a conical structure. Compared with a cylindrical structure, a conical support body 305 requires less material to manufacture.

[0033] As one embodiment of the present invention, the outer wall of the self-supporting stirring head 30 is provided with threads, and the stationary shoulder 40 is provided with a feed hole 402, which is directly opposite the threads. As the self-supporting stirring head 30 rotates at high speed, the wire feedstock enters the feed hole 402 of the stationary shoulder 40, is sheared into particles by the threads of the self-supporting stirring head 30, and is transported downward along the threads of the self-supporting stirring head 30.

[0034] As one of the embodiments of the present invention, the stationary shoulder 40 is a conical structure, and the inner wall of the stationary shoulder 40 is a conical structure. On the one hand, the conical structure is to adapt to the structure of the self-supporting stirring head 30, and on the other hand, the conical structure can increase the accommodation space of the stationary shoulder 40 to a certain extent. The additive material enters through the feed hole 402 opened on the side wall of the stationary shoulder 40 and is transported downward along the thread. When the feed rate of the additive material is greater than the additive consumption rate, blockage may occur. The provision of a conical structure can ensure that there is a larger accommodation space in the stationary shoulder 40. The conical structure is larger at the top and smaller at the bottom, ensuring that there is still a large space above the feed hole 402. When the additive material is paused but the feeding is still in progress, the material entering the stationary shoulder 40 can be temporarily retained inside the stationary shoulder 40, acting as a temporary buffer to prevent blockage.

[0035] As one of the embodiments of the present invention, the self-supporting stirring head 30 includes: a clamping end 301, a mating portion 306 and a conical screw 302. The clamping end 301 is connected to a power source for transmitting power for rotating the conical screw 302. The two ends of the mating portion 306 are respectively connected to the clamping end 301 and the conical screw 302. The mating portion 306 is connected to the inner wall of the locking end 401 of the stationary shoulder 40 for limiting the conical screw 302. The outer wall of the conical screw 302 is provided with a thread, and a space for accommodating additive material is provided between the conical screw 302 and the inner wall of the stationary shoulder 40.

[0036] As one of the embodiments of the present invention, the distance between the support body 305 and the end surface of the self-supporting stirring head 30 is 0.2 mm-5 mm.

[0037] The self-supporting friction stir additive manufacturing (FSAM) device operates as follows: the self-supporting stirring head 30 rotates at high speed, penetrating the substrate 10 from the side. Wire feedstock enters through the feed hole 402 of the stationary shoulder 40, where it is sheared into particles by the tapered screw 302 of the self-supporting stirring head 30. Through friction with the substrate 10 and intense plastic deformation, the wire particles are thermoplastically deposited to form an additive layer. Subsequently, spatial three-dimensional additive manufacturing begins along a predetermined path. The self-supporting stirring head 30 separates from the substrate 10, and thermoplastic material is continuously extruded from the tapered screw 302, falling into the concave shoulder 304 within the self-supporting body. The diameter of the concave shoulder 304 is larger than the end diameter of the stationary shoulder 40, allowing all extruded thermoplastic material to converge and form a densely deposited layer. The thickness of the deposited layer is determined by the distance between the support body 305 and the end faces of the tapered screw 302. The tapered inner wall 403 of the stationary shoulder 40 is designed to constrain the extruded material, preventing it from being thrown out due to the centrifugal force of high-speed rotation. The support body 305 replaces the rigid pad and provides real-time support to the deposited layer during the friction stir deposition process, thereby realizing the preparation of unsupported three-dimensional metal thin-walled parts 20 at any angle in space.

[0038] According to another aspect of the present invention, a self-supporting friction stir additive manufacturing method is provided, the manufacturing method comprising the steps of:

[0039] S1: The stirring head rotates at high speed and penetrates into the substrate from the side;

[0040] S2: Feed the raw material into the gap between the stationary shoulder and the stirring head for stirring and friction by the stirring head, which shears the raw material into particles and transmits them downward;

[0041] S3: Through the friction and severe plastic deformation between the stirring head and the substrate, the raw material is thermoplastically deposited to form an additive layer. Then the stirring head separates from the substrate and performs spatial three-dimensional additive manufacturing along a preset path.

[0042] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0043] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A self-supporting friction stir additive manufacturing device, characterized in that: include: A stirring head, the stirring head is used for thermally plasticizing the deposition material; A stationary shoulder, wherein a receiving space is provided inside the stationary shoulder for restraining the thermoplastic material, and the end of the stirring end of the stirring head is flush with the end of the stationary shoulder; A support body is connected to the stirring head, and the support body is arranged at the end of the stirring end of the stirring head. The support body is provided with a support surface for providing support for the deposition material on the side close to the stirring head, and the opening of the end of the stationary shaft shoulder faces the support surface.

2. The self-supporting friction stir additive manufacturing device according to claim 1, characterized in that: The support surface is a circular surface, and the center of the support surface is concave to form a circular surface with a sunken center.

3. The self-supporting friction stir additive manufacturing device according to claim 2, characterized in that: The stirring head is connected to the support body through a stirring needle. The stirring head is a frustum structure. The stirring needle is arranged at the center of the bottom surface of the stirring head and the support surface.

4. The self-supporting friction stir additive manufacturing device according to claim 1, characterized in that: The support body is a conical structure, the support surface is located on the top surface of the support body, and the center of the support surface is sunken and concave.

5. The self-supporting friction stir additive manufacturing device according to claim 4, characterized in that: The stationary shoulder is a conical structure, and the inner wall of the stationary shoulder is a conical structure.

6. The self-supporting friction stir additive manufacturing device according to claim 5, characterized in that: The diameter of the support surface is larger than the diameter of the stationary shoulder end.

7. The self-supporting friction stir additive manufacturing device according to claim 4, characterized in that: The outer wall of the stirring head is provided with a thread, and the static shaft shoulder is provided with a feed hole, and the feed hole is directly opposite to the thread.

8. The self-supporting friction stir additive manufacturing device according to claim 1, characterized in that: The stirring head includes: a clamping end, a mating portion and a conical screw. The clamping end is connected to a power source for transmitting power for rotating the conical screw. The two ends of the mating portion are respectively connected to the clamping end and the conical screw. The mating portion is connected to the inner wall of the stationary shaft shoulder for limiting the conical screw. The outer wall of the conical screw is provided with a thread. A space for accommodating additive material is provided between the conical screw and the inner wall of the stationary shaft shoulder.

9. The self-supporting friction stir additive manufacturing device according to claim 1, characterized in that: The distance between the support body and the end face of the stirring head is 0.2mm-5mm.

10. A self-supporting friction stir additive manufacturing method, characterized in that: Adding material by the self-supporting friction stir additive manufacturing device according to any one of claims 1 to 9, comprising: S1: The stirring head rotates at high speed and penetrates into the substrate from the side; S2: Feeding the raw material into the gap between the stationary shoulder and the stirring head for stirring and friction by the stirring head, which shears the raw material into particles and transmits them downward; S3: Through the friction and violent plastic deformation between the stirring head and the substrate, the raw material is thermoplastically deposited to form an additive layer. Then the stirring head separates from the substrate and performs spatial three-dimensional additive manufacturing along a preset path.

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