An additive manufacturing method for metal forming parts and the metal forming parts thereof

Abstract

This invention relates to the field of metal printing technology, specifically to an additive manufacturing method for metal forming parts and the metal forming parts thereof. The method includes printing multi-segment bent pipe structures. The pipe structures have multiple bends in the printing direction, and the pipe structures have corresponding outer and inner curved surfaces on their outer periphery at the bends. The method is as follows: a forming platform gradually descends with the printing process, and during the descent, the pipe structure, as well as a support structure and an anti-wrinkle structure for auxiliary forming, are simultaneously formed on the forming platform. The support structure at least encloses the outer curved surface of the pipe structure and is adapted to its contour. The anti-wrinkle structure spans and connects the inner curved surfaces of adjacent pipe segments to suppress printing wrinkles. This application provides continuous, stable, and effective support for multi-segment bent pipe structures, preventing quality problems such as melt pool collapse, interlayer deformation, or loss of contour accuracy caused by excessive local overhang during printing, thereby improving the forming quality of complex pipelines.

Description

Technical Field

[0001] This invention relates to the field of metal printing technology, and in particular to an additive manufacturing method for metal forming parts and the metal forming parts thereof. Background Technology

[0002] In the field of spacecraft design and manufacturing, the internal structure is highly complex, resulting in intricate layouts of internal tubular structures. To avoid interference between different components, tubular structures often require multiple carefully designed bending processes to adapt to the confined and complex space environment. Simultaneously, given the various harsh mechanical environments that spacecraft must withstand during launch and operation, tubular structures must possess sufficient strength to ensure functional stability and reliability. In traditional forming processes, if tubular structures are formed using a single-layer, flat method, while a large area can be formed in one go, the resulting structural strength is insufficient to meet design requirements. To improve the strength of tubular structures, their forming posture needs to be changed, allowing them to be formed vertically with the tube segments tilted to the forming surface. However, this forming method is not without its drawbacks. When tubular structures are formed directly in an inclined posture, the overhang angle may exceed the material's self-supporting capacity, leading to structural collapse or deformation and other quality problems, severely impacting the overall performance and safety of the spacecraft. Summary of the Invention

[0003] The purpose of this invention is to provide an additive manufacturing method for metal forming parts and the metal forming parts thereof, so as to solve the problem of structural collapse or deformation when vertical forming of tubular structures in the prior art.

[0004] The technical solution of this invention is: an additive manufacturing method for metal formed parts, comprising:

[0005] For printing multi-segment bent tubular structures, the tubular structure having multiple bent segments in the printing direction, and the tubular structure having corresponding outer and inner bent surfaces on the outer periphery of each bend, the method is as follows:

[0006] The molding platform is initially reset and has the same height as the printed molding surface in the initial state;

[0007] The forming platform descends gradually with the printing process, and during the descent, the forming platform simultaneously forms the tubular structure as well as the support structure and anti-wrinkle structure used to assist in forming. The support structure at least encloses the outer curved surface of the tubular structure and is adapted to its contour. The anti-wrinkle structure spans and connects the inner curved surface of adjacent tubular sections to suppress printing wrinkles.

[0008] Preferably, the support structure includes a first auxiliary structure that is constructed upwards at a variable angle in the vertical direction starting from the forming surface. The first auxiliary structure is a thin-walled structure and encloses at least one of the bent outer curved surfaces.

[0009] Preferably, the support structure further includes a second auxiliary structure and a third auxiliary structure, which are intersected and formed on the same side of the first auxiliary structure and connected to the outer curved surface of the tubular structure to resist the lateral and torsional forces generated by the tubular structure during the printing process.

[0010] Preferably, the first auxiliary structure, the second auxiliary structure and the third auxiliary structure are each provided with a plurality of separation holes for separation at the connection points with the tubular structure.

[0011] Preferably, the forming platform has a support structure that provides support for the tubular structure. The support structure is constructed as a frame structure to support the overhanging portion of the tubular structure.

[0012] Preferably, the supporting structure includes:

[0013] The first and second load-bearing structures are arranged in parallel.

[0014] A first connecting structure and a second connecting structure are intersected between the first load-bearing structure and the second load-bearing structure;

[0015] And a bracket structure formed on the top of the first load-bearing structure and the second load-bearing structure, used to directly support the suspended part of the tubular structure.

[0016] Preferably, the supporting structure and the supporting structure share some structures, such that the first connecting structure and the second connecting structure of the supporting structure are respectively connected to the second auxiliary structure and the third auxiliary structure of the supporting structure.

[0017] A metal forming part includes a tubular structure, a support structure, a supporting structure, and an anti-wrinkle structure, wherein the support structure, the supporting structure, and the anti-wrinkle structure are all plate-like structures and are metallurgically bonded to the outer contour of the tubular structure.

[0018] Preferably, the tubular structure is a multi-plane composite bend in which the center path undergoes continuous, non-coplanar deflection in space. The central axes of the first flange, the first pipe segment, the second pipe segment, and the second flange of the tubular structure are all in a skew-plane straight-line relationship in space. The supporting structure, the bearing structure, and the anti-wrinkle structure together construct a complete supporting skeleton that runs through the key bending area and the overhanging part of the entire tubular structure.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] (1) By pre-designing an integrated support structure that is formed synchronously with the tubular structure in key areas such as the outer curved surface where the overhang angle exceeds the material’s self-supporting capacity, it can provide continuous, stable and effective support for the multi-segment bent tubular structure formed in an inclined vertical manner, preventing quality problems such as melt pool collapse, interlayer deformation or loss of contour accuracy caused by excessive local overhang during the printing process, thereby significantly improving the forming consistency and geometric accuracy of complex pipelines, and ensuring that they meet the structural integrity and safety and reliability requirements of spacecraft for critical fluid pipelines under harsh working conditions.

[0021] (2) The support structure provides key regional reinforcement support for the bend of the tubular structure. It not only directly enhances the local forming stability of the transition surface during the printing process and effectively prevents the collapse and deformation of the area due to insufficient material accumulation or stress concentration, but also, through collaboration with the outer bending surface support structure, constructs a continuous support system from the outer bending surface to the transition surface, ensuring the integrity and dimensional accuracy of the entire bending area outline.

[0022] (3) The anti-wrinkle structure provides key internal tension control for tubular structures, effectively suppressing the compressive stress generated in the inner bending area due to heat accumulation and uneven material shrinkage during the printing process, thereby directly preventing the formation of surface wrinkles, warping or micro cracks, and significantly improving the forming smoothness and dimensional stability of the inner bending surface. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0024] Figure 1 This is a schematic diagram of the tubular structure described in this invention;

[0025] Figure 2 This is a schematic diagram of the structure of a metal forming part according to the present invention;

[0026] Figure 3 This is a schematic diagram of an additive manufacturing method for a metal forming part according to the present invention;

[0027] Figure 4 This is a schematic diagram of the forward structure of a metal forming part according to the present invention;

[0028] Figure 5 This is a schematic diagram of the reverse structure of a metal forming part according to the present invention.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Pipe structure; 11. First flange; 12. Second flange; 13. First pipe section; 14. Second pipe section; 15. Outer bend; 16. Inner bend; 17. Transition surface; 2. Support structure; 21. First auxiliary structure; 22. Second auxiliary structure; 23. Third auxiliary structure; 24. Separation hole; 3. Support structure; 31. First load-bearing structure; 32. Second load-bearing structure; 33. First connection structure; 34. Second connection structure; 35. Bracket structure; 4. Anti-wrinkle structure; 100. Forming platform; 200. Laser beam; 300. Forming surface. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0032] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0033] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0034] like Figures 1 to 3 As shown, an additive manufacturing method for metal forming parts is used to print a multi-segment bent pipe structure 1 in a printing direction. The pipe structure 1 has multiple bent pipe segments in the printing direction and is gradually formed in a vertical posture. The pipe structure 1 includes a first flange 11, a second flange 12, and multiple bent pipe segments between them. Adjacent bent pipe segments have corresponding outer bending surfaces 15 and inner bending surfaces 16 on the outer periphery of their bends, and there are two corresponding transition surfaces 17 between the outer bending surfaces 15 and the inner bending surfaces 16.

[0035] Set the current cladding layer of pipe structure 1 to the forming surface 300 of the molten surface formed on a constant horizontal reference.

[0036] The forming platform 100 is initially reset and has the same height as the printing forming surface 300 in the initial state;

[0037] As the printing process progresses, the forming platform 100 gradually descends, forming a tubular structure 1, a support structure 2, a supporting structure 3, and an anti-wrinkle structure 4. Specifically, the forming platform 100 descends by one layer thickness to make room for each new powder layer. A very thin layer of metal powder is laid on the forming platform 100 at its initial position using rollers. Based on the slicing data, the laser beam 200 selectively scans and melts the first layer of powder, causing the molten metal powder droplets to metallurgically bond with the forming platform 100. The forming platform 100 then descends by one layer thickness, and the rollers lay another layer of powder, covering the first layer. The laser beam 200 scans the second support section, fusing it with the first support layer below. This process is repeated, and the tubular structure 1, support structure 2, and supporting structure 3 are gradually formed upwards from the forming platform 100.

[0038] In this embodiment, the pipe structure 1 can be a fuel line, an oxidizer line, or a coolant line. The following description mainly uses the fuel line as an example.

[0039] In this embodiment, a first pipe segment 13 and a second pipe segment 14 are sequentially bent and connected between the first flange 11 and the second flange 12 of the pipe structure 1. The central path of the pipe structure 1, from the first flange 11 to the second flange 12, undergoes a series of continuous, non-coplanar deflections in space. The central axes of the first flange 11, the first pipe segment 13, the second pipe segment 14, and the second flange 12 are all in a skew-plane linear relationship in space.

[0040] To ensure that the tubular structure 1 is printed in a vertical position, targeted support designs are required for at least the following risk areas that exceed the material's self-supporting capacity:

[0041] Bending the outer curved surface 15:

[0042] The outer bend 15 at the bend between the first flange 11 and the first pipe section 13;

[0043] The outer bend 15 at the bend between the first pipe section 13 and the second pipe section 14;

[0044] Sidewall and transition surface 17:

[0045] The side wall of the second pipe section 14;

[0046] The side wall of the second flange 12;

[0047] The transition surface 17 at the bend between the second pipe section 14 and the second flange 12;

[0048] Inner curved surface 16:

[0049] The inner bend 16 of the first pipe section 13 and the second pipe section 14;

[0050] The inner bend 16 of the second pipe section 14 and the second flange 12.

[0051] Based on the aforementioned geometric characteristics and molding risks, a set of regional composite supports was implemented. Through the collaborative design and integration of support structure 2, support structure 3 and anti-wrinkle structure, the feasibility and final quality of vertical molding of complex tubular parts were ensured.

[0052] In the molding process of the tubular structure 1, firstly, the first flange 11 of the tubular structure 1 serves as the base structure, directly printed and firmly attached to the molding surface 300. Subsequently, synchronously with the first flange 11, the base portion of the support structure 2 also begins to form from the molding surface 300. As the printing process proceeds layer by layer, the support structure 2 extends upward from the base and toward the outer curved surface 15 between the first flange 11 and the first pipe segment 13, ultimately firmly connecting with the side edge of the first flange 11 and the outer curved surface 15 to form a continuous support structure 2 from the base to the bottom of the overhanging outer curved surface 15. This effectively avoids collapse, sagging, or interlayer separation caused by delayed or missing support, ensuring the molding quality of the transition area at the beginning of the bend.

[0053] The support structure 2 includes at least a first auxiliary structure 21, which is formed on the forming surface 300. The first auxiliary structure 21 is constructed upwards at a variable angle in the vertical direction and is adapted to the contour trend of the outer curved surface 15. That is, the first auxiliary structure 21 encloses the outer curved surface 15 of the pipe-like structure 1. Specifically, a first auxiliary structure 21 is formed on the outer curved surface 15 at the bend between the first flange 11 and the first pipe segment 13, and at the bend between the first pipe segment 13 and the second pipe segment 14. Preferably, the first auxiliary structure 21 is a thin-walled structure along its extension direction.

[0054] like Figure 4 and Figure 5 As shown, preferably, the support structure 2 further includes a second auxiliary structure 22 and a third auxiliary structure 23, both of which are thin-walled plate-like structures. The second auxiliary structure 22 and the third auxiliary structure 23 are intersectingly formed on the outer curved surface 15 of the first flange 11 and the first pipe section 13, and are formed on the same side of the first auxiliary structure 21.

[0055] Since the tubular structure 1 is printed vertically, in this state, the first tube segment 13 is inclined at approximately 45° to the horizontal plane. The bend between the first flange 11 and the first tube segment 13 will bear the weight of the first tube segment 13 and above, and the first tube segment 13 will generate lateral and torsional forces at this bend. The second auxiliary structure 22 and the third auxiliary structure 23 effectively resist the lateral or torsional forces from the first tube segment 13, preventing the model from deflecting and macroscopically collapsing during the printing process, and further suppressing microscopic interlayer displacement or vibration, ensuring the contour accuracy and surface smoothness of the bent tube segment, especially the outer bend surface 15.

[0056] More preferably, the first auxiliary structure 21, the second auxiliary structure 22, and the third auxiliary structure 23 are all provided with separation holes 24 for separation from the tubular structure 1. Multiple separation holes 24 are arranged in a single row at the connection points between the three structures and the tubular structure 1. The fracture of the support structure 2 and the tubular structure 1 will strictly occur along the predetermined hole lines, avoiding uncontrollable fractures that could cause scratches, dents, or residues to the tubular structure 1 body, especially to the smooth outer curved surface 15 and the flange surface, thus greatly improving the yield rate.

[0057] The support structure 2, which is formed simultaneously at the bend between the first pipe segment 13 and the second pipe segment 14, includes only the first auxiliary structure 21. The first auxiliary structure 21 starts from the forming surface 300 together with the first flange 11, and then the main body of the first auxiliary structure 21 extends upward closely to fit the outer contour of the second pipe segment 14, and finally covers the transition surface 17 between the second flange 12 and the bend of the pipe segment.

[0058] The envelope structure and parametric thin-wall construction of support structure 2 achieve a balance among several interdependent indicators, including printing success rate, model surface quality, support material consumption, and post-processing efficiency. Support structure 2 not only precisely supports complex external curved contours through surface contact, preventing printing collapse and greatly improving model surface quality, but also achieves material conservation and ease of dismantling through fixed-point placement of key parts and variable-angle thin-wall extension. Ultimately, while ensuring molding reliability, it significantly improves the economy and ease of use of the entire printing process.

[0059] In this embodiment, during the molding process of the pipe structure 1, two sets of support structures 3 are simultaneously molded, meaning both sets of support structures 3 are formed from the molding surface 300. Each support structure 3 includes a first load-bearing structure 31 and a second load-bearing structure 32, both constructed as plate-like structures and extending upwards in the vertical direction, providing the main compressive and bending stiffness, effectively transmitting the load from the upper pipe section to the molding platform 100. The first load-bearing structure 31 and the second load-bearing structure 32 are arranged parallel to each other, and between them, a first connecting structure 33 and a second connecting structure 34 are formed. The first connecting structure 33 and the second connecting structure 34 are both constructed as plate-like structures and are arranged in an intersecting manner to resist lateral forces and prevent structural instability. This effectively prevents the two parallel load-bearing structures from undergoing relative displacement, torsion, or buckling under pressure, ensuring that the entire support system maintains its supporting force throughout the entire printing height.

[0060] The supporting structure 3 also includes a bracket structure 35, which is formed on top of the first load-bearing structure 31 and the second load-bearing structure 32. The bracket structure 35 is used to directly support the pipe structure 1. The first load-bearing structure 31, the second load-bearing structure 32, the first connecting structure 33, the second connecting structure 34, and the bracket structure 35 together constitute a frame structure, which reduces material usage and achieves lightweight design while achieving high strength and rigidity.

[0061] Specifically, one support structure 3 is formed at the bottom of the inclined second pipe segment 14. The bracket structure 35 of this support structure 3 is parallel to and formed on the outer contour of the bottom of the second pipe segment 14 to support the second pipe segment 14. Another support structure 3 is formed at the bottom of the second flange 12 and the transition surface 17 between the second flange 12 and the second pipe segment 14 to support the second flange 12 and the transition surface 17 between the second flange 12 and the second pipe segment 14. After multiple bends of the first pipe segment 13 and the second pipe segment 14, the second flange 12 is located above the first flange 11 and the first pipe segment 13. Therefore, this support structure 3 shares part of its structure with the support structure 2 to simplify the overall structure. Specifically, the support structure 3 connects the first connecting structure 33 and the second connecting structure 34 of the first pipe segment 13 with the second auxiliary structure 22 and the third auxiliary structure 23 of the support structure 2. That is, the first connecting structure 33 corresponds to the second auxiliary structure 22, and the second connecting structure 34 corresponds to the third auxiliary structure 23. The second supporting structure 3 no longer needs its own independent lower support part. It directly utilizes the second auxiliary structure 22 and the third auxiliary structure 23 of the supporting structure 2, which significantly reduces the total number of structures and simplifies the overall structure.

[0062] Thus, the support structure 2 and the supporting structure 3 work together to construct a complete support framework that runs through the key bending area of ​​the entire tubular structure 1. It connects the isolated points of potential overhang, that is, it connects the various bends and overhangs of the tubular structure 1 to form a unified support system. The support structure 2 for the second tube segment 14 closely conforms to its outer contour and extends to the key transition surface 17, while the supporting structure 3 provides precise support at the bottom. By sharing some structural components, they form a closely cooperating whole. The support structure 2 effectively resists the deformation forces during the printing of the second tube segment 14, maintaining its shape accuracy, while the supporting structure 3 stably bears the load, preventing sagging and swaying. Simultaneously, the shared structure reduces the overall number and complexity of the structure, saves support materials, lowers costs, and improves post-processing efficiency, comprehensively ensuring the printing quality of the second tube segment 14 and the economic ease of the entire printing process.

[0063] Anti-wrinkle structures 4 are simultaneously formed on the inner curved surfaces 16 at the bends of the first pipe segment 13 and the second pipe segment 14. The anti-wrinkle structure 4 spans and connects two adjacent pipe segments at the inner curved surfaces 16, and is used to suppress surface wrinkles and deformations caused by material shrinkage or stress concentration during the printing process. Preferably, the connection between the anti-wrinkle structure 4 and the inner curved surfaces 16 at the bends of the first pipe segment 13 and the second pipe segment 14 is provided with a plurality of separation holes 24 to facilitate the removal of the anti-wrinkle structure 4 after printing is completed.

[0064] Another anti-wrinkle structure 4 is simultaneously formed on the inner bending surface 16 of the second pipe section 14 and the second flange 12, which is used to suppress surface wrinkles and deformations caused by stress concentration between the second pipe section 14 and the second flange 12 during the printing process.

[0065] This application provides a specific 3D printing method for a multi-segment bent tube structure 1. For multi-segment bent tube structures 1 with different bending shapes, a support structure 2, a supporting structure 3, and an anti-wrinkle structure 4 can be added according to the actual structure.

[0066] This application also provides a metal forming part, including a tubular structure 1, a supporting structure 2, a supporting structure 3, and an anti-wrinkle structure 4. The supporting structure 2, the supporting structure 3, and the anti-wrinkle structure 4 are all plate-like structures, and the three are metallurgically bonded to the outer contour of the tubular structure 1.

[0067] The above embodiments are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and thus all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention.

Claims

1. An additive manufacturing method of a metal formed part, characterized in that, for printing a multi-bent pipe-like structure (1) having a plurality of bent pipe sections in a printing forming direction, the pipe-like structure (1) has corresponding outer bending surfaces (15) and inner bending surfaces (16) on the outer peripheral side thereof at the bending portions thereof, the method is as follows: a forming platform (100) is initially reset and has the same height as a printing forming surface (300) in an initial state; the forming platform (100) is gradually lowered along with the printing process, and in the printing process of the lowering, the forming platform (100) synchronously forms the pipe-like structure (1) and a support structure (2) and a wrinkle-resistant structure (4) for assisting in forming, the support structure (2) at least envelopes the bent outer bending surfaces (15) of the pipe-like structure (1) and is adapted to the profile thereof, and the wrinkle-resistant structure (4) spans and connects the inner bending surfaces (16) of adjacent pipe sections for suppressing printing wrinkles; the support structure (2) includes a first auxiliary structure (21) that is upwardly constructed at an angle variable based on the vertical direction from the forming surface (300), the first auxiliary structure (21) is a thin-walled structure and envelopes at least one of the bent outer bending surfaces (15); the support structure (2) further includes a second auxiliary structure (22) and a third auxiliary structure (23), the second auxiliary structure (22) and the third auxiliary structure (23) are cross-formed on the same side of the first auxiliary structure (21) and are connected to the outer bending surfaces (15) of the pipe-like structure (1) to resist lateral forces and twisting forces generated by the pipe-like structure (1) during the printing process; a plurality of separation holes (24) for separation are provided at the connection of the first auxiliary structure (21), the second auxiliary structure (22) and the third auxiliary structure (23) with the pipe-like structure (1); the forming platform (100) is formed with a supporting structure (3) for providing support to the pipe-like structure (1), the supporting structure (3) is configured as a frame structure for supporting the overhanging portion of the pipe-like structure (1) the supporting structure (3) includes: a first load-bearing structure (31) and a second load-bearing structure (32) arranged in parallel; a first connecting structure (33) and a second connecting structure (34) arranged crosswise between the first load-bearing structure (31) and the second load-bearing structure (32); and a bracket structure (35) formed on the top of the first load-bearing structure (31) and the second load-bearing structure (32) for directly bearing the overhanging portion of the pipe-like structure (1).

2. A method of additive manufacturing of a metal formed piece according to claim 1, characterized in that: the supporting structure (3) and the support structure (2) share part of the structure, so that the first connecting structure (33) and the second connecting structure (34) of the supporting structure (3) are respectively connected to the second auxiliary structure (22) and the third auxiliary structure (23) of the support structure (2).

3. Metal shaped part made by the method of additive manufacturing of a metal shaped part according to any one of claims 1 or 2, characterized in that: It comprises a tubular structure (1), a supporting structure (2), a bearing structure (3) and an anti-wrinkle structure (4), the supporting structure (2), the bearing structure (3) and the anti-wrinkle structure (4) are all plate-like structures and are metallurgically combined with the outer contour of the tubular structure (1) respectively.

4. A metal formed piece according to claim 3, characterized in that: The tubular structure (1) is a multi-plane composite bent pipe with the central path experiencing continuous, non-coplanar deflection in space, the central axis of the first flange (11), the central axis of the first pipe section (13), the central axis of the second pipe section (14) and the central axis of the second flange (12) of the tubular structure (1) are all in a non-coplanar linear relationship in space, and the supporting structure (2), the bearing structure (3) and the anti-wrinkle structure (4) jointly construct a complete supporting framework penetrating through the key bending area and the overhanging part of the entire tubular structure (1).

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