3D printing closed cavity and 3D printing method thereof

Abstract

The present application relates to a kind of 3D printing closed cavity and its 3D printing method, belong to 3D printing technical field, solve the weight of the large number of parts of the existing closed cavity support structure and the problem of large internal volume of parts occupation.The closed cavity includes top surface, side wall and bottom surface, top surface, side wall and bottom surface form the closed cavity containing inner cavity;3D printing forming support structure is arranged in the inner cavity, and the top surface is 3D printing formed on the support structure.This closed cavity can be self-formed by 3D printing.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing technology, and in particular to a 3D printing closed cavity and a 3D printing method thereof. Background Art

[0002] Selective laser melting (SLM), as a typical representative of additive manufacturing (3D printing) technology, is not limited by the complexity of parts. It can effectively make up for the shortcomings of traditional processes and realize the "free growth" of highly complex structural parts. It has broad application prospects in the aerospace field.

[0003] Some typical cavity structures are traditionally formed by casting, machining and welding, which has complicated processes and long production cycles, bringing great troubles to the product development progress. However, the use of laser selective melting integrated forming can effectively shorten the production process. After printing is completed, only the assembly surface needs to be processed, which can effectively improve production efficiency. However, the closed inner cavity has a large overhanging plane, which cannot be directly printed and formed, which significantly affects the application of laser selective melting in cavity structures. Summary of the Invention

[0004] In view of the above analysis, an embodiment of the present invention aims to provide a 3D printed closed cavity and a 3D printing method thereof, so as to solve the problem that the existing closed cavity cannot be self-formed in one piece through 3D printing.

[0005] In one aspect, the present invention provides a 3D printed closed cavity, the closed cavity comprising a top surface, side walls, and a bottom surface, wherein the top surface, side walls, and bottom surface form a closed cavity containing an inner cavity;

[0006] A 3D printed support structure is provided in the inner cavity, and the top surface is 3D printed on the support structure.

[0007] Preferably, the support structure comprises a plurality of prism support blocks and a support frame arranged below the prism support blocks;

[0008] The upper end surfaces of the plurality of prism support blocks form the 3D printing support surface of the top surface; the lower end surface of the prism support block is connected to the upper end surface of the support frame;

[0009] The lower end surface of the support frame is connected to the side wall or the bottom surface.

[0010] Preferably, the pyramid support block is a quadrangular prism.

[0011] Preferably, the upper end surface of the pyramid support block is larger than the lower end surface, the upper end surface of the pyramid support block matches the top surface, and the lower end surface of the pyramid support block coincides with the upper end surface of the support frame.

[0012] Preferably, the support frame includes a primary support frame and a secondary support frame arranged in sequence from top to bottom;

[0013] The primary support frame includes four columns, the upper end surfaces of the four columns are respectively connected to the lower end surfaces of four adjacent prism support blocks, and the lower end surfaces of the four columns are connected to each other to form the lower end surface of the primary support frame;

[0014] The upper end surface of the secondary support frame is connected to the lower end surface of the primary support frame, and the lower end surface of the secondary support frame is connected to the side wall or the bottom surface.

[0015] Preferably, the support frame includes the primary support frame, the intermediate support frame and the secondary support frame arranged in sequence from top to bottom;

[0016] The intermediate-level support frame includes four columns, the upper end surfaces of the four columns are respectively connected to the lower end surfaces of four adjacent first-level support frames, and the lower end surfaces of the four columns are connected to each other to form the lower end surface of the intermediate-level support frame; the lower end surface of the intermediate-level support frame is connected to the upper end surface of the second-level support frame.

[0017] Preferably, the secondary support frame is rod-shaped, the upper end surface of the rod is connected to the lower end surface of the primary support frame, and the lower end surface of the secondary support frame is connected to the side wall and / or bottom surface.

[0018] Preferably, the secondary support frame is in the shape of a vertically placed flat plate, the top side of the flat plate is connected to the lower end surface of one or more of the primary support frames, and one side surface of the flat plate is connected to the side wall.

[0019] Preferably, the lower end surfaces of the plurality of prism support blocks are located on the same plane.

[0020] In a second aspect, the present invention further provides a 3D printing method for the above-mentioned 3D printed closed cavity, the method comprising:

[0021] (a) Print bottom surface;

[0022] (b) Printing sidewalls;

[0023] (c) printing a secondary support frame from one side of the side wall;

[0024] (d) printing a primary support frame from the upper end surface of the secondary support frame, or printing an intermediate support frame from the upper end surface of the secondary support frame, and then printing a primary support frame on the upper end surface of the intermediate support frame;

[0025] (e) printing a pyramid support block from the upper end surface of the primary support frame;

[0026] (f) printing a top surface on the upper end surface of the prism support block;

[0027] (g) A 3D printed closed cavity is formed with the top surface, side walls, support structure and bottom surface integrally formed.

[0028] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0029] 1. The present invention provides a support structure between the top surface and the side wall of the closed cavity, so that the closed cavity can be self-formed in one piece through 3D printing technology.

[0030] 2. The present invention utilizes a pyramid support block to convert the top surface area of ​​the pyramid support block from its large end face (upper end face) to its small end face (lower end face). Simultaneously, the two ends of the support frame are connected to the small end face and sidewall of the pyramid support block, achieving support and further reducing the support surface area. This support structure weighs less than 20% of the weight of a physical support structure and occupies less than 20% of the internal volume of the component, avoiding the problems of significantly increasing the weight and occupying a large amount of the internal volume of the component. The support structure does not need to be removed.

[0031] 3. The lower end surfaces of the multiple pyramid support blocks of the present invention are located on the same horizontal plane, which can convert the top surfaces of various irregularly shaped surfaces into flat surfaces. Therefore, the support structure of the present invention is applicable to any irregularly shaped top surface.

[0032] 4. The 3D printing method of the present invention can realize the integrated printing and self-forming of the closed cavity, solving the problem that the top surface in the closed cavity is difficult to form during the printing process, and realizes the printing and self-forming of the top surface by adding less material weight.

[0033] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of the present invention will be described in the following description, and some advantages will become apparent from the description or be learned through practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0035] Figure 1 A three-dimensional schematic diagram of a 3D printed closed cavity provided by one embodiment of the present invention;

[0036] Figure 2 A front view of a 3D printed closed cavity provided by one embodiment of the present invention;

[0037] Figure 3 A side view of a 3D printed closed cavity provided by one embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the structure of the pyramid support block of the present invention;

[0039] Figure 5 A three-dimensional schematic diagram of a 3D printed closed cavity provided in another embodiment of the present invention.

[0040] Reference numerals:

[0041] 1-top surface; 2-prism support block; 3-first-level support frame; 4-second-level support frame; 5-side wall; 6-intermediate-level support frame; 7-bottom surface. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0043] In one aspect, the present invention provides a closed cavity, such as Figure 1-3 As shown, the closed cavity includes a top surface 1, a side wall 5 and a bottom surface 7, and the top surface 1, the side wall 5 and the bottom surface 7 form a closed cavity containing an inner cavity;

[0044] A 3D printed support structure is provided in the inner cavity, and the top surface 1 is 3D printed on the support structure.

[0045] Compared with the prior art, the present invention provides a support structure in the closed cavity, so that the closed cavity can be integrally formed by 3D printing technology.

[0046] In one embodiment, the support structure includes a plurality of prism support blocks 2 and a support frame arranged below the prism support blocks 2;

[0047] The upper end surfaces of the plurality of prism support blocks 2 form the 3D printing support surface of the top surface 1; the lower end surface of the prism support block 2 is connected to the upper end surface of the support frame;

[0048] The lower end surface of the support frame is connected to the side wall 5 or the bottom surface 7.

[0049] Exemplarily, the pyramid support block 2 is arranged below the top surface 1 .

[0050] It should be noted that the pyramid support block 2 is a solid structure.

[0051] In one embodiment, Figure 1-4 As shown, each of the pyramid support blocks 2 is a quadrangular prism.

[0052] In one embodiment, the upper end surface of the pyramid support block 2 is larger than the lower end surface, the upper end surface of the pyramid support block 2 matches the top surface 1, and the lower end surface of the pyramid support block 2 coincides with the upper end surface of the support frame.

[0053] The support structure of the present invention converts the top surface area of ​​the pyramid support block 2 from the large end surface (upper end surface) to the small end surface (lower end surface) of the pyramid support block 2. Simultaneously, the two ends of the support frame are connected to the small end surface and sidewall 5 of the pyramid support block 2, respectively, achieving the desired support effect while further reducing the support surface area. This support structure weighs less than 20% of the weight of a solid support structure and occupies less than 20% of the internal volume of the component, avoiding the problems of significantly increasing the weight and occupying a large amount of internal volume of the component. The support structure does not need to be removed.

[0054] It should be noted that, unless otherwise specified, the "upper" and "lower" in the present invention refer to the "upper" and "lower" in the main view of the part.

[0055] It should be noted that the side wall 5 extends downward along the edge of the top surface 1 and is connected to the bottom surface 7 to form an inner cavity space.

[0056] The shape of the side wall 5 can be determined according to the shapes of the top surface 1 and the bottom surface 7, such as a columnar shape, a cylindrical shape, an irregular cylindrical shape, or a cylindrical shape with the diameters of the upper and lower ends being smaller than the diameter of the middle section.

[0057] In order to ensure the self-printing formation of the side wall 5, the angle between the side wall 5 and the horizontal plane is greater than or equal to 45°.

[0058] In the present invention, top surface 1 is a surface requiring support or a portion thereof. The angle between top surface 1 and the horizontal plane is less than 45°, which does not meet the self-forming conditions for 3D printed parts without support or results in poor surface quality after forming. The structural shapes of top surface 1 include, but are not limited to, flat surfaces, curved surfaces, and boss structures. Its main characteristic is that it cannot self-form during the forming process. The wall thickness of top surface 1 can be any value greater than 0.5 mm, and the upper and lower surfaces of top surface 1 may include local features such as bosses, through-holes, and reinforcing ribs.

[0059] In one embodiment, the support frame includes a primary support frame 3 and a secondary support frame 4 arranged in sequence from top to bottom; the support structure includes multiple primary support frames 3 and multiple secondary support frames 4.

[0060] The first-level support frame 3 includes four columns, the upper end faces of the four columns are respectively connected to the lower end faces of four adjacent prism support blocks 2, and the lower end faces of the four columns are connected to each other to form the lower end face of the first-level support frame 3; the "adjacent" refers to four prism support blocks 2 that can be surrounded by a square.

[0061] The upper end surface of the secondary support frame 4 is connected to the lower end surface of the primary support frame 3 , and the lower end surface of the secondary support frame 4 is connected to the side wall 5 or the bottom surface 7 .

[0062] It is understood that four columns extend downward from the lower end surfaces of four adjacent pyramid support blocks 2, and the lower end surfaces of the four columns are interconnected to form a primary support frame 3. The function of the primary support frame 3 is to convert the four lower end support surfaces of the four pyramid support blocks 2 into a single support surface at the upper end of the primary support frame 3, further reducing the area of ​​the required support plane and the volume of the support frame structure; the primary support frame 3 is also used to support the printing of the pyramid support blocks 2.

[0063] In one embodiment, the lower end surface of the primary support frame 3 is a horizontal surface.

[0064] In one embodiment, the upper end surface of the primary support frame 3 and the lower end surface of the prism support block 2 are consistent in shape and completely overlap.

[0065] In the present invention, the lower end surface of the primary support frame 3 is used to connect to the upper end surface of the secondary support frame 4. The cross-sectional shape and area of ​​the lower end surface of the primary support frame 3 can be adjusted according to the required strength of the support structure. The cross-sectional shape and area of ​​the lower end surface of the primary support frame 3 can be different from those of the upper end surface of the primary support frame 3.

[0066] Exemplarily, the cross-sectional shape of the lower end surface of the primary support frame 3 is circular, elliptical, rectangular, etc., and the cross-sectional area is larger or smaller than that of the upper end surface.

[0067] It is understandable that the lower end surface of the primary support frame 3 extends toward the side wall 5 to form a secondary support frame 4. The secondary support frame 4 is used to support the printing of the primary support frame 3.

[0068] In one embodiment, the upper end surface of the secondary support frame 4 is consistent in shape with the lower end surface of the primary support frame 3 and completely overlaps with each other.

[0069] In the present invention, the cross-sectional shape and area of ​​the lower end surface of the secondary support frame 4 can be adjusted according to the strength requirements of the support structure.

[0070] Exemplarily, the cross-sectional shape of the lower end surface of the secondary support frame 4 is circular, elliptical, rectangular, etc., and the cross-sectional area is larger or smaller than that of the upper end surface.

[0071] In order to ensure the self-forming printing of the primary support frame 3 and the secondary support frame 4, the angle between each column of the primary support frame 3 and the horizontal plane is greater than or equal to 45°, and the angle between the secondary support frame 4 and the horizontal plane is greater than or equal to 45°.

[0072] It should be noted that when the required support area is large, an intermediate support frame 6 with a structure similar to the primary support frame 3 can be set between the primary support frame 3 and the secondary support frame 4 to further reduce the support area.

[0073] In one embodiment, the support frame includes the primary support frame 3, the intermediate support frame 6 and the secondary support frame 4 arranged in sequence from top to bottom;

[0074] The intermediate-level support frame 6 includes four columns, the upper end faces of the four columns are respectively connected to the lower end faces of four adjacent first-level support frames 3, and the lower end faces of the four columns are connected to each other to form the lower end face of the intermediate-level support frame 6; the lower end face of the intermediate-level support frame 6 is connected to the upper end face of the second-level support frame 4.

[0075] It is understandable that if Figure 1 and 2 As shown, four intermediate struts extend downward from the lower end surfaces of four adjacent primary support frames 3. The upper end surfaces of the four intermediate struts overlap and connect with the lower end surfaces of the four adjacent primary support frames 3, and the lower end surfaces of the four intermediate struts are connected to each other, thereby reducing the area of ​​the four lower end surfaces of the four primary support frames 3 to the lower end surface of one intermediate support frame 6. The lower end surface of the intermediate support frame 6 is connected to the upper end surface of the secondary support frame 4. Each strut of the intermediate support frame 6 forms an angle greater than or equal to 45° with the horizontal plane.

[0076] In the present invention, there can be multiple intermediate support frames 6, which are arranged in the same manner as described above, so as to gradually reduce the overall support area.

[0077] In one embodiment, the secondary support frame 4 is rod-shaped, the upper end surface of the rod is connected to the lower end surface of the primary support frame 3 or the intermediate support frame 6, and the lower end surface of the secondary support frame 4 is connected to the side wall 5 and / or bottom surface 7.

[0078] In one embodiment, the secondary support frame 4 is in the shape of a vertically placed flat plate, the top side of the flat plate is connected to the lower end surface of one or more of the primary support frames 3 or the intermediate support frames 6, and one side side of the flat plate is connected to the side wall 5.

[0079] It can be understood that when the required support strength of the parts is higher, the structure of the secondary support frame 4 can be transformed from one end face connected to the side wall 5 to the entire side of the secondary support frame 4 being connected to the side wall 5, that is, the secondary support frame 4 is a right-angled triangular plate that is perpendicular to both the top surface 1 and the side wall 5, and the two right-angled sides are respectively parallel to the top surface 1 and the side wall 5 that are perpendicular to each other, one of the right-angled sides is used to connect to the primary support frame 3, and the other right-angled side is connected to the side wall 5, such as Figure 5As shown, the connection strength between the secondary support frame 4 and the side wall 5 can be increased to prevent deformation and cracking of the connection position due to excessive stress.

[0080] In one embodiment, the secondary support frame 4 in the closed cavity can be connected to the side wall 5 from different directions; preferably, the secondary support frame 4 is connected to a side wall position that is relatively close thereto.

[0081] In the present invention, the function of the pyramid support block 2 is to convert the area of ​​the top surface 1 from the area of ​​the upper end surface of the pyramid support block 2 to the area of ​​the lower end surface, that is, from a large area to a small area, thereby reducing the area to be supported.

[0082] It can be understood that the upper end surfaces of the multiple pyramidal support blocks 2 constitute the top surface 1, that is, the top surface 1 is divided into multiple squares, which are the upper end surfaces of the pyramidal support blocks 2, and a pyramidal support block 2 extends downward from each square.

[0083] In one embodiment, the lower end surfaces of the plurality of pyramid support blocks 2 are located on the same plane. The pyramid support block 2 can convert the top surface 1 of various irregularly shaped surfaces into a plane formed by the lower end surfaces of the pyramid support block 2 to improve the stability of the support.

[0084] Furthermore, the lower end surface of the prism support block 2 is a horizontal surface.

[0085] In order to ensure the self-forming printing of the pyramid support block 2, the angle between the side surface of the pyramid support block 2 and the horizontal plane is greater than or equal to 45°.

[0086] In the present invention, the area of ​​the upper end surface of the prism support block 2 determines the area of ​​the overhanging plane that each prism support block 2 can support, and the area of ​​the lower end surface of the prism support block 2 determines the area of ​​the end surface of the support frame connected thereto, and further determines the structural strength of the support frame. Therefore, the area of ​​the upper and lower end surfaces of the prism support block 2 can be adjusted according to the stress level of the supporting structure.

[0087] In one embodiment, the upper end face and the lower end face of the pyramid support block 2 are square, the side length of the upper end face is 4-8 mm, and the side length of the lower end face is 0.5-2 mm.

[0088] In one embodiment, the angle between the sidewall 5 and the horizontal plane is greater than or equal to 45°. The sidewall 5 can be directly printed and formed, and can be used to connect with the structure of the secondary support frame 4, providing support for the secondary support frame 4 and the structures above it. Similarly, the structural form of the sidewall 5 is not limited to a flat surface, and can also be various curved or shaped surfaces, as long as the above-mentioned self-forming conditions are met.

[0089] On the other hand, the present invention also provides a top surface 3D printing method, using the above-mentioned support structure, the method comprising:

[0090] (a) Printing bottom surface 7;

[0091] (b) Printing side wall 5;

[0092] (c) printing a secondary support frame 4 from one side of the side wall 5;

[0093] (d) printing the primary support frame 3 from the upper end surface of the secondary support frame 4, or printing the intermediate support frame 6 from the upper end surface of the secondary support frame 4, and then printing the primary support frame 3 on the upper end surface of the intermediate support frame 6;

[0094] (e) printing the prism support block 2 from the upper end surface of the primary support frame 3;

[0095] (f) printing a top surface 1 on the upper end surface of the prism support block 2;

[0096] (g) A 3D printed closed cavity is formed with the top surface 1, side walls 5, support structure and bottom surface 7 integrally formed.

[0097] Specifically, during the 3D printing process, the bottom surface 7 and the side wall 5 are printed and formed first, and then the secondary support frame 4 is gradually printed and formed from one side of the side wall 5. The primary support frame 3 is gradually printed and formed through the upper end face support of the secondary support frame 4, or the intermediate support frame 6 is gradually printed and formed through the upper end face support of the secondary support frame 4. The primary support frame 3 is gradually printed and formed through the upper end face support of the intermediate support frame 6. The upper end face of each column of the primary support frame 4 supports the prism support block 2 to be printed and formed. Finally, the top surface 1 is printed and formed on the upper end face of the prism support block 2 to complete the 3D printing of the top surface 1.

[0098] In one embodiment, the 3D printing method is a selective laser melting method.

[0099] The 3D printing method for a closed cavity of the present invention can realize the self-forming of the top surface in the closed cavity, solving the problem that the top surface is difficult to form during printing. The self-forming of the top surface is realized by adding less material weight, eliminating the need to remove the support structure.

[0100] The 3D printing closed cavity and the 3D printing method thereof of the present invention are further described below through specific embodiments.

[0101] Example 1-1

[0102] A 3D printed closed cavity is provided:

[0103] The closed cavity includes a top surface 1, a side wall 5 and a bottom surface 7, and the top surface 1, side wall 5 and bottom surface 7 form a closed cavity containing an inner cavity; a support structure is arranged between the top surface 1 and the side wall 5; the support structure includes a plurality of prism support blocks 2 arranged below the top surface 1 and a support frame arranged below the prism support block 2; the upper end surface of the prism support block 2 is larger than the lower end surface, the upper end surface of the prism support block 2 coincides with the top surface 1, the lower end surface of the prism support block 2 coincides with the upper end surface of the support frame, and the lower end surface of the support frame is connected to the side wall 5; the side wall 5 is located on one side below the top surface 1, and is arranged at an angle to the top surface 1.

[0104] The prism support block 2 is a solid structure. Each of the prism support blocks 2 is a quadrangular prism. The upper end surfaces of the multiple prism support blocks 2 constitute the top surface 1, that is, the top surface 1 is divided into multiple squares, and the square is the upper end surface of the prism support block 2, and a prism support block 2 extends downward from each square. The lower end surfaces of the multiple prism support blocks 2 are located on the same plane. The lower end surface of the prism support block 2 is a horizontal plane. The angle between the side surface of the prism support block 2 and the horizontal plane is equal to 45°, and the upper and lower end surfaces of the prism support block 2 are squares, the side length of the upper end surface is 5 mm, and the side length of the lower end surface is 1 mm.

[0105] The support frame includes a primary support frame 3 and a secondary support frame 4, arranged sequentially from top to bottom. The support structure includes multiple primary support frames 3 and multiple secondary support frames 4. The primary support frame 3 includes four columns, the upper end surfaces of which are respectively connected to the lower end surfaces of four adjacent pyramidal support blocks 2. The lower end surfaces of the four columns are interconnected to form the lower end surface of the primary support frame 3. The upper end surface of the secondary support frame 4 is connected to the lower end surface of the primary support frame 3, and the lower end surface of the secondary support frame 4 is connected to the side wall 5. The lower end surface of the primary support frame 3 is horizontal. The upper end surface of the primary support frame 3 is consistent in shape with the lower end surface of the pyramidal support block 2 and completely overlaps. The upper end surface of the secondary support frame 4 is consistent in shape with the lower end surface of the primary support frame 3 and completely overlaps. Each column of the primary support frame 3 forms a 45° angle with the horizontal plane, and each secondary support frame 4 forms a 45° angle with the horizontal plane.

[0106] Example 1-2

[0107] A 3D printed closed cavity is provided:

[0108] The closed cavity includes a top surface 1, a side wall 5 and a bottom surface 7, wherein the top surface 1, the side wall 5 and the bottom surface 7 form a closed cavity containing an inner cavity; a support structure is provided between the top surface 1 and the side wall 5;

[0109] The support structure includes a plurality of prism support blocks 2 arranged below the top surface 1 and a support frame arranged below the prism support block 2; the upper end surface of the prism support block 2 is larger than the lower end surface, the upper end surface of the prism support block 2 coincides with the top surface 1, the lower end surface of the prism support block 2 coincides with the upper end surface of the support frame, and the lower end surface of the support frame is connected to the side wall 5; the side wall 5 is located on one side below the top surface 1 and is arranged at an angle to the top surface 1.

[0110] The prism support block 2 is a solid structure. Each of the prism support blocks 2 is a quadrangular prism. The upper end surfaces of the multiple prism support blocks 2 constitute the top surface 1, that is, the top surface 1 is divided into multiple squares, and the square is the upper end surface of the prism support block 2, and a prism support block 2 extends downward from each square. The lower end surfaces of the multiple prism support blocks 2 are located on the same plane. The lower end surface of the prism support block 2 is a horizontal plane. The angle between the side surface of the prism support block 2 and the horizontal plane is equal to 45°, and the upper and lower end surfaces of the prism support block 2 are squares, the side length of the upper end surface is 5 mm, and the side length of the lower end surface is 1 mm.

[0111] The support frame includes a primary support frame 3 and a secondary support frame 4, arranged sequentially from top to bottom. The support structure includes multiple primary support frames 3 and multiple secondary support frames 4. The primary support frame 3 includes four columns, the upper end surfaces of which are respectively connected to the lower end surfaces of four adjacent pyramidal support blocks 2. The lower end surfaces of the four columns are interconnected to form the lower end surface of the primary support frame 3. The upper end surface of the secondary support frame 4 is connected to the lower end surface of the primary support frame 3, and the lower end surface of the secondary support frame 4 is connected to the side wall 5. The lower end surface of the primary support frame 3 is horizontal. The upper end surface of the primary support frame 3 is consistent in shape with the lower end surface of the pyramidal support block 2 and completely overlaps. The upper end surface of the secondary support frame 4 is consistent in shape with the lower end surface of the primary support frame 3 and completely overlaps. Each column of the primary support frame 3 forms a 45° angle with the horizontal plane, and each secondary support frame 4 forms a 45° angle with the horizontal plane.

[0112] An intermediate support frame 6 having a structure similar to that of the primary support frame 3 is provided between the primary support frame 3 and the secondary support frame 4 .

[0113] Examples 1-3

[0114] A 3D printed closed cavity is provided, such as Figure 5 As shown:

[0115] The closed cavity includes a top surface 1, a side wall 5 and a bottom surface 7, wherein the top surface 1, the side wall 5 and the bottom surface 7 form a closed cavity containing an inner cavity; a support structure is provided between the top surface 1 and the side wall 5;

[0116] The support structure includes a plurality of prism support blocks 2 arranged below the top surface 1 and a support frame arranged below the prism support block 2; the upper end surface of the prism support block 2 is larger than the lower end surface, the upper end surface of the prism support block 2 coincides with the top surface 1, the lower end surface of the prism support block 2 coincides with the upper end surface of the support frame, and the lower end surface of the support frame is connected to the side wall 5; the side wall 5 is located on one side below the top surface 1 and is arranged at an angle to the top surface 1.

[0117] The prism support block 2 is a solid structure. Each of the prism support blocks 2 is a quadrangular prism. The upper end surfaces of the multiple prism support blocks 2 constitute the top surface 1, that is, the top surface 1 is divided into multiple squares, and the square is the upper end surface of the prism support block 2, and a prism support block 2 extends downward from each square. The lower end surfaces of the multiple prism support blocks 2 are located on the same plane. The lower end surface of the prism support block 2 is a horizontal plane. The angle between the side surface of the prism support block 2 and the horizontal plane is equal to 45°, and the upper and lower end surfaces of the prism support block 2 are squares, the side length of the upper end surface is 5 mm, and the side length of the lower end surface is 1 mm.

[0118] The support frame includes a primary support frame 3 and a secondary support frame 4, arranged sequentially from top to bottom. The support structure includes multiple primary support frames 3 and multiple secondary support frames 4. The primary support frame 3 includes four columns, the upper end surfaces of which are respectively connected to the lower end surfaces of four adjacent pyramidal support blocks 2. The lower end surfaces of the four columns are interconnected to form the lower end surface of the primary support frame 3. The upper end surface of the secondary support frame 4 is connected to the lower end surface of the primary support frame 3, and the lower end surface of the secondary support frame 4 is connected to the adjacent inclined surface 5. The lower end surface of the primary support frame 3 is horizontal. The upper end surface of the primary support frame 3 is consistent in shape with the lower end surface of the pyramidal support block 2 and completely overlaps. The upper end surface of the secondary support frame 4 is consistent in shape with the lower end surface of the primary support frame 3 and completely overlaps. Each column of the primary support frame 3 forms a 45° angle with the horizontal plane, and each secondary support frame 4 forms a 45° angle with the horizontal plane.

[0119] An intermediate support frame 6 having a structure similar to that of the primary support frame 3 is provided between the primary support frame 3 and the secondary support frame 4 .

[0120] The entire side surface of the secondary support frame 4 is connected to the side wall 5, that is, the secondary support frame 4 is a right-angled triangular plate that is perpendicular to both the top surface 1 and the side wall 5, and the two right-angled sides are parallel to the top surface 1 and the side wall 5 that are perpendicular to each other, one of the right-angled sides is used to connect to the primary support frame 3, and the other right-angled side is connected to the side wall 5.

[0121] Examples 1-4

[0122] A 3D printed closed cavity is provided:

[0123] The closed cavity includes a top surface 1, a side wall 5 and a bottom surface 7, and the top surface 1, side wall 5 and bottom surface 7 form a closed cavity containing an inner cavity; a support structure is arranged between the top surface 1 and the side wall 5; the support structure includes a plurality of prism support blocks 2 arranged below the top surface 1 and a support frame arranged below the prism support block 2; the upper end surface of the prism support block 2 is larger than the lower end surface, the upper end surface of the prism support block 2 coincides with the top surface 1, the lower end surface of the prism support block 2 coincides with the upper end surface of the support frame, and the lower end surface of the support frame is connected to the side wall 5; the side wall 5 is located on one side below the top surface 1, and is arranged at an angle to the top surface 1.

[0124] The prism support block 2 is a solid structure. Each of the prism support blocks 2 is a quadrangular prism. The upper end surfaces of the multiple prism support blocks 2 constitute the top surface 1, that is, the top surface 1 is divided into multiple squares, and the square is the upper end surface of the prism support block 2, and a prism support block 2 extends downward from each square. The lower end surfaces of the multiple prism support blocks 2 are located on the same plane. The lower end surface of the prism support block 2 is a horizontal plane. The angle between the side surface of the prism support block 2 and the horizontal plane is equal to 45°, and the upper and lower end surfaces of the prism support block 2 are squares, the side length of the upper end surface is 5 mm, and the side length of the lower end surface is 1 mm.

[0125] The support frame includes a primary support frame 3 and a secondary support frame 4, arranged sequentially from top to bottom. The support structure includes multiple primary support frames 3 and multiple secondary support frames 4. The primary support frame 3 includes four columns, the upper end surfaces of which are respectively connected to the lower end surfaces of four adjacent pyramidal support blocks 2. The lower end surfaces of the four columns are connected to each other, forming the lower end surface of the primary support frame 3. The upper end surface of the secondary support frame 4 is connected to the lower end surface of the primary support frame 3, and the lower end surface of the secondary support frame 4 is connected to the bottom surface 7. The lower end surface of the primary support frame 3 is a horizontal plane. The upper end surface of the primary support frame 3 is consistent in shape with the lower end surface of the pyramidal support block 2 and completely overlaps. The upper end surface of the secondary support frame 4 is consistent in shape with the lower end surface of the primary support frame 3 and completely overlaps. Each column of the primary support frame 3 forms a 45° angle with the horizontal plane, and each secondary support frame 4 forms a 45° angle with the horizontal plane.

[0126] Example 2-1

[0127] (a) Printing bottom surface 7;

[0128] (b) Printing side wall 5, where the angle between the side wall 5 and the horizontal plane is 90°.

[0129] (c) Printing a secondary support frame 4 from one side of the side wall 5, with the angle between the secondary support frame 4 and the horizontal plane being 45°.

[0130] (d) Printing the primary support frame 3 from the upper end surface of the secondary support frame 4; the upper end surface of the secondary support frame 4 is consistent in shape with the lower end surface of the primary support frame 3 and completely overlaps; the angle between the primary support frame 3 and the horizontal plane is 45°.

[0131] (e) Print a pyramid support block 2 from the upper end face of each column of the first-level support frame 3; the upper end face of each column of the first-level support frame 3 is consistent in shape with the lower end face of the pyramid support block 2 and completely overlaps; the upper end face and the lower end face of the pyramid support block 2 are square, the side length of the upper end face is 5 mm, and the side length of the lower end face is 1 mm; the angle between the side face of the pyramid support block 2 and the horizontal plane is 45°.

[0132] (f) Printing a top surface 1 on the upper end surface of the pyramid support block 2, wherein the wall thickness of the top surface 1 is 0.6 mm and the angle between the top surface 1 and the horizontal plane is 0°;

[0133] (g) A 3D printed closed cavity is formed with the top surface 1, side walls 5, support structure and bottom surface 7 integrally formed.

[0134] The support structure of this closed cavity weighs only 18% of the weight of a solid support and occupies 18% of the internal volume of the part. The solid support refers to a completely solid triangular support formed between the top surface and side walls that can be formed by 3D printing.

[0135] Example 2-2

[0136] (a) Printing bottom surface 7;

[0137] (b) Printing side wall 5, the angle between side wall 5 and the horizontal plane is 85°.

[0138] (c) Printing a secondary support frame 4 from one side of the side wall 5, with the angle between the secondary support frame 4 and the horizontal plane being 50°.

[0139] (d) Print the intermediate support frame 6 from the upper end face of the secondary support frame 4. The upper end face of the secondary support frame 4 and the lower end face of the intermediate support frame 6 have the same shape and completely overlap. Each support column of the intermediate support frame 6 has an angle of 50° with the horizontal plane.

[0140] (e) Print the first-level support frame 3 from the upper end face of each pillar of the intermediate-level support frame 6; the upper end face of each pillar of the intermediate-level support frame 6 is consistent in shape with the lower end face of the first-level support frame 3 and completely overlaps; the angle between each pillar of the first-level support frame 3 and the horizontal plane is 50°.

[0141] (f) Print a pyramid support block 2 from the upper end face of each column of the first-level support frame 3; the upper end face of each column of the first-level support frame 3 is consistent in shape with the lower end face of the pyramid support block 2 and completely overlaps; the upper end face and the lower end face of the pyramid support block 2 are square, the side length of the upper end face is 5 mm, and the side length of the lower end face is 1 mm; the angle between the side face of the pyramid support block 2 and the horizontal plane is 50°.

[0142] (g) A top surface 1 is printed on the upper end surface of the pyramid support block 2. The wall thickness of the top surface 1 is 0.6 mm, and the angle between the top surface 1 and the horizontal plane is 5°.

[0143] (h) A 3D printed closed cavity is formed with the top surface 1, side walls 5, support structure and bottom surface 7 integrally formed.

[0144] The support structure weighs only 16.3% of the solid support and occupies 16.3% of the internal volume of the part. The solid support refers to the completely solid triangular support formed between the top surface and the side walls that can be formed by 3D printing.

[0145] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A 3D printed closed cavity, characterized in that: The closed cavity comprises a top surface (1), a side wall (5) and a bottom surface (7), wherein the top surface (1), the side wall (5) and the bottom surface (7) form a closed cavity containing an inner cavity; the structural shape of the top surface (1) comprises a plane, a curved surface, and a boss structure; A 3D printed support structure is provided in the inner cavity, and the top surface (1) is 3D printed on the support structure; The support structure comprises a plurality of prism support blocks (2) and a support frame arranged below the prism support blocks (2); The upper end surfaces of the plurality of prism support blocks (2) form a 3D printing support surface of the top surface (1); the lower end surface of the prism support block (2) is connected to the upper end surface of the support frame; The lower end surface of the support frame is connected to the side wall (5) or the bottom surface (7); The prism support block (2) is a quadrangular prism; The upper end surface of the prism support block (2) is larger than the lower end surface, the upper end surface of the prism support block (2) matches the top surface (1), and the lower end surface of the prism support block (2) coincides with the upper end surface of the support frame; the lower end surfaces of the plurality of prism support blocks (2) are located on the same plane; the angle between the side surface of the prism support block (2) and the horizontal plane is greater than or equal to 45°; The function of the prism support block 2 is to convert the area of ​​the top surface (1) from the area of ​​the upper end surface of the prism support block (2) to the area of ​​the lower end surface, that is, to convert a large area into a small area, thereby reducing the area required for support; The support frame comprises a primary support frame (3) and a secondary support frame (4) arranged in sequence from top to bottom; The first-level support frame (3) comprises four columns, the upper end surfaces of the four columns are respectively connected to the lower end surfaces of four adjacent prism support blocks (2), and the lower end surfaces of the four columns are connected to each other to form the lower end surface of the first-level support frame (3); The upper end surface of the secondary support frame (4) is connected to the lower end surface of the primary support frame (3), and the lower end surface of the secondary support frame (4) is connected to the side wall (5) or the bottom surface (7); The angle between each column of the first-level support frame (3) and the horizontal plane is greater than or equal to 45°, and the angle between the second-level support frame (4) and the horizontal plane is greater than or equal to 45°; The weight of the support structure is within 20% of the weight of the solid support structure, and the internal volume of the part it occupies is within 20% of the solid support structure. The support structure does not need to be removed.

2. The 3D printed closed cavity according to claim 1, characterized in that: The support frame comprises the primary support frame (3), the intermediate support frame (6) and the secondary support frame (4) which are arranged in sequence from top to bottom; The intermediate support frame (6) comprises four columns, the upper end surfaces of the four columns are respectively connected to the lower end surfaces of four adjacent primary support frames (3), and the lower end surfaces of the four columns are connected to each other to form the lower end surface of the intermediate support frame (6); the lower end surface of the intermediate support frame (6) is connected to the upper end surface of the secondary support frame (4).

3. The 3D printed closed cavity according to claim 1, characterized in that: The secondary support frame (4) is rod-shaped, the upper end surface of the rod is connected to the lower end surface of the primary support frame (3), and the lower end surface of the secondary support frame (4) is connected to the side wall (5) and / or the bottom surface (7).

4. The 3D printed closed cavity according to claim 1, characterized in that: The secondary support frame (4) is in the shape of a vertically placed flat plate, the top side of the flat plate is connected to the lower end surface of one or more primary support frames (3), and one side of the flat plate is connected to the side wall (5).

5. The 3D printing method for a closed cavity according to any one of claims 1 to 4, characterized in that: The method comprises: (a) Printing bottom surface (7); (b) Printing sidewalls (5); (c) printing a secondary support frame (4) from one side of the side wall (5); (d) printing the primary support frame (3) from the upper end surface of the secondary support frame (4), or printing the intermediate support frame (6) from the upper end surface of the secondary support frame (4), and then printing the primary support frame (3) on the upper end surface of the intermediate support frame (6); (e) printing a pyramid support block (2) from the upper end surface of the first-level support frame (3); (f) printing a top surface (1) on the upper end surface of the prism support block (2); (g) A 3D printed closed cavity is formed by integrally forming a top surface (1), side walls (5), a support structure and a bottom surface (7).

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