Breathable metal structures with pore gradients and their manufacturing methods
By using laser sintering to manufacture a permeable metal structure with a pore gradient, the problem of poor permeability and mechanical properties caused by uneven pores in existing permeable metals is solved, achieving a balance between high permeability and mechanical strength, and effectively solving the problem of trapped air during injection molding.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NATIONAL KAOHSIUNG UNIVERSITY OF SCIENCE & TECHNOLOGY
- Filing Date
- 2023-02-23
- Publication Date
- 2026-05-26
Smart Images
Figure CN117984620B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of layered product technology, and more particularly to a breathable metal structure with a pore gradient and its manufacturing method. Background Technology
[0002] Please refer to the following invention patents from Taiwan: TWI269814B (Manufacturing Method of Breathable Mold Steel), TW201929982A (Porous Metal and Preparation Method Thereof), CN107868899B (A Breathable Steel for Injection Molding and Preparation Method Thereof), CN105922514B (A Mold with Good Breathability and Cooling Effect), and CN106867. Patent application 016A, entitled "A Sintering Method and Apparatus for Preparing Open-Pore Polymer Materials," discloses manufacturing methods related to breathable metals. However, the disclosed methods mainly employ high-temperature sintering of metal powders. While this allows the manufactured metal products to have breathable properties, the uneven size and irregular shape of the sintered pores, along with their random and discontinuous distribution, prevents the achievement of optimal breathability. This results in poor venting. Furthermore, if existing breathable metals are sintered using a loose method to improve venting, their hardness decreases significantly, mechanical properties deteriorate, and the surface quality of injection-molded products cannot be guaranteed. Conversely, while a denser sintering method ensures mechanical strength and surface quality, it cannot handle the large amounts of gas generated during molding, thus failing to address issues such as trapped air, weld seams, and short shots. Summary of the Invention
[0003] This invention relates to a breathable metal structure with a pore gradient and its manufacturing method. Its main purpose is to provide a breathable metal structure with a pore gradient and its manufacturing method that has good mechanical strength, can effectively solve the problem of air trapping during the product molding process, and takes into account the surface quality of the product.
[0004] To achieve the above-mentioned objectives, on one hand, the present invention provides a breathable metal structure with a pore gradient, comprising a first layer having a first surface and a second surface, wherein a second layer is bonded to the first surface of the first layer, the first layer having a plurality of first pores, and the second layer having a plurality of second pores, wherein the positions of the plurality of first pores in the first layer correspond to and communicate with the positions of the plurality of second pores in the second layer, and the diameter of the second pores is smaller than the diameter of the first pores.
[0005] In a preferred embodiment of the present invention, the pore diameter of the first hole in the first stack is greater than 80 micrometers, and the pore diameter of the second hole in the second stack is less than 50 micrometers.
[0006] In a preferred embodiment of the present invention, the breathable metal structure with a pore gradient further includes a third layer, the third layer being bonded to the second surface of the first layer, the third layer having a plurality of third pores, the positions of the plurality of third pores of the third layer corresponding to and communicating with the positions of the plurality of first pores of the first layer, and the diameter of the third pores being less than or equal to the diameter of the first pores.
[0007] In a preferred embodiment of the present invention, the pore diameter of the first hole in the first stack is greater than 80 micrometers, and the pore diameter of the third hole in the third stack is greater than 80 micrometers or less than 50 micrometers.
[0008] On the other hand, the present invention provides a method for manufacturing a breathable metal structure with a pore gradient, the implementation steps of which include:
[0009] Step A: Fabricating the first layer: Metal powder is compactly and evenly spread to form a first layer. Then, a laser beam is used to scan the first layer with multiple parallel and spaced first linear paths. Each first linear path in the first layer forms a first molten pool width. The first line spacing between two adjacent first linear paths in the first layer is greater than the first molten pool width. The difference between the first line spacing and the first molten pool width forms a first gap. Metal powder is then compactly and evenly spread on the first layer to form a second layer. A laser beam is then used to scan the second layer with multiple parallel and spaced second linear paths. The second linear paths in the second layer are parallel to and spaced from the first linear paths in the first layer. The second linear path of the second stacked layer is accompanied by a second molten pool width. The second line spacing formed between two adjacent second linear paths of the second stacked layer is greater than the second molten pool width. The difference between the second line spacing and the second molten pool width of the second stacked layer forms a second gap. The first gap of the first stacked layer and the second gap of the second stacked layer are arranged in an alternating manner to form a plurality of first holes distributed in a grid. The plurality of first stacked layers and the plurality of second stacked layers are stacked in sequence to form a first stacked layer. The positions of the plurality of first holes formed by the alternating arrangement of the plurality of first stacked layers and the plurality of second stacked layers correspond to each other to form a plurality of continuous first holes that penetrate the first stacked layer.
[0010] Step B: Fabricating the second layer: Metal powder is compactly spread on the first surface of the first layer to form a third layer. A laser beam is then used to scan the third layer with multiple parallel and spaced third linear paths. Each third linear path in the third layer forms a third molten pool width. The distance between two adjacent third linear paths in the third layer is greater than the third molten pool width, and the difference between the distance between the third linear paths and the third molten pool width forms a third gap. Metal powder is then compactly spread on the third layer to form a fourth layer. A laser beam is then used to scan the fourth layer with multiple parallel and spaced fourth linear paths. The fourth linear paths in the fourth layer are set at an angle to the third linear paths in the third layer, and each fourth linear path in the fourth layer forms a fourth molten pool width. The fourth line spacing formed between two adjacent fourth linear paths of the fourth stacked layer is greater than the width of the fourth molten pool. The difference between the fourth line spacing and the width of the fourth molten pool of the fourth stacked layer forms a fourth gap. The third gap of the third stacked layer and the fourth gap of the fourth stacked layer are arranged in an alternating manner to form a plurality of second holes in a grid-like distribution. At least one third stacked layer and at least one fourth stacked layer are stacked in sequence to form a second stacked layer. The positions of the plurality of second holes formed by the alternating at least one third stacked layer and at least one fourth stacked layer correspond to each other to form a plurality of continuous second holes penetrating the second stacked layer. The positions of the plurality of second holes in the second stacked layer correspond to and communicate with the positions of the plurality of first holes in the first stacked layer. The diameter of the second hole is smaller than the diameter of the first hole.
[0011] In a preferred embodiment of the present invention, the width of the first molten pool and the width of the second molten pool of the first stack are 70 micrometers to 150 micrometers, the length of the first line spacing and the second line spacing are 150 micrometers to 300 micrometers, the first gap of the first stack and the second gap of the second stack are greater than 80 micrometers, and the aperture of the first hole formed by the alternation of the first gap of the first stack and the second gap of the second stack is greater than 80 micrometers.
[0012] In a preferred embodiment of the present invention, the width of the third molten pool and the width of the fourth molten pool of the second stack are 70 to 150 micrometers, the third line spacing and the fourth line spacing are 120 to 200 micrometers, the third gap of the third stack and the fourth gap of the fourth stack are less than 50 micrometers, and the aperture of the second hole formed by the interlacing of the third gap of the third stack and the fourth gap of the fourth stack is less than 50 micrometers.
[0013] In a preferred embodiment of this invention, the method for manufacturing the breathable metal structure with a pore gradient further includes:
[0014] To create a third layer, metal powder is compactly spread on the second surface of the first layer to form a fifth layer. A laser beam is then used to scan the fifth layer with multiple parallel and spaced fifth linear paths. Each fifth linear path in the fifth layer forms a fifth molten pool width. The spacing between two adjacent fifth linear paths in the fifth layer is greater than the fifth molten pool width, and the difference between the spacing and the molten pool width forms a fifth gap. Next, metal powder is compactly spread on the fifth layer to form a sixth layer. A laser beam is then used to scan the sixth layer with multiple parallel and spaced sixth linear paths. The sixth linear paths in the sixth layer are angled to the fifth linear paths in the fifth layer, and each sixth linear path in the sixth layer forms a sixth molten pool width. The sixth line spacing formed between two adjacent sixth linear paths is greater than the width of the sixth molten pool. The difference between the sixth line spacing and the width of the sixth molten pool of the sixth stacked layer forms a sixth gap. The fifth gap of the fifth stacked layer and the sixth gap of the sixth stacked layer are arranged in an alternating manner to form a plurality of third holes in a grid-like distribution. At least one fifth stacked layer and at least one sixth stacked layer are stacked in sequence to form a third stacked layer. The positions of the plurality of third holes formed by the alternating arrangement of the at least one fifth stacked layer and at least one sixth stacked layer correspond to each other to form a plurality of continuous third holes penetrating the third stacked layer. The positions of the plurality of third holes in the third stacked layer correspond to and communicate with the positions of the plurality of first holes in the first stacked layer, and the diameter of the third hole is less than or equal to the diameter of the first hole.
[0015] In a preferred embodiment of this invention, the width of the fifth molten pool and the width of the sixth molten pool of the third stack are 70 micrometers to 150 micrometers, the fifth line spacing and the sixth line spacing are 150 micrometers to 300 micrometers or 120 micrometers to 200 micrometers, the fifth gap of the fifth stack and the sixth gap of the sixth stack are greater than 80 micrometers or less than 50 micrometers, and the aperture of the third hole formed by the interlacing of the fifth gap of the fifth stack and the sixth gap of the sixth stack is greater than 80 micrometers or less than 50 micrometers.
[0016] In a preferred embodiment of this invention, the included angle between the first gap and the second gap of the first stack is . 2nd gap = 1stcos(90-θ), the included angle between the third and fourth gaps of the second stack is... 4th gap = 3rd cos(90-θ), the included angle between the fifth and sixth gaps of the third stack is... 6th gap = 5th cos(90-θ); where the tilt angle of the first gap is θ, the tilt angle of the second gap is 90-θ, 0<θ<90; the tilt angle of the third gap is θ, the tilt angle of the fourth gap is 90-θ, 0<θ<90; the tilt angle of the fifth gap is θ, the tilt angle of the sixth gap is 90-θ, 0<θ<90.
[0017] The present invention has the following beneficial effects:
[0018] 1. The permeable metal structure with pore gradient of the present invention and its manufacturing method can set the cavity in the second stack with smaller pore diameter so that the product can form a fine and smooth surface quality when it is injection molded in the cavity. In addition, the first stack with larger pore diameter can effectively dissipate the large amount of gas generated during the molding process of plastic products, so as to solve the problem of trapped air accumulation.
[0019] 2. The permeable metal structure with pore gradient of the present invention and its manufacturing method can adjust the pore size of the third layer located outside the first layer according to the needs of product manufacturing, so as to take into account the mechanical strength and venting requirements of the mold made therefrom. Attached Figure Description
[0020] Figure 1 This is an exploded perspective view of the present invention;
[0021] Figure 2 This is a cross-sectional view of the present invention;
[0022] Figure 3 This is a flowchart of the present invention;
[0023] Figure 4 This is a diagram showing the laser beam scanning state of the present invention;
[0024] Figure 5 This is a schematic diagram of the laser beam scanning states of the first and second layers of the present invention;
[0025] Figure 6 This is a schematic diagram of the laser beam scanning states of the third and fourth layers of the present invention;
[0026] Figure 7 This is a schematic diagram of the laser beam scanning state of the fifth and sixth layers of the present invention.
[0027] Explanation of icon numbers:
[0028] 1. First stack; 11. First void; 2. Second stack; 21. Second void; 3. Third stack; 31. Third void; 4. First stack; 41. First linear path; 42. First molten pool width; 43. First line spacing; 44. First gap; 5. Second stack; 51. Second linear path; 52. Second molten pool width; 53. Second line spacing; 54. Second gap; 6. Third stack; 61. Third linear path; 62. Third molten pool Width; 63, Third line spacing; 64, Third gap; 7, Fourth layer; 71, Fourth linear path; 72, Fourth molten pool width; 73, Fourth line spacing; 74, Fourth gap; 8, Fifth layer; 81, Fifth linear path; 82, Fifth molten pool width; 83, Fifth line spacing; 84, Fifth gap; 9, Sixth layer; 91, Sixth linear path; 92, Sixth molten pool width; 93, Sixth line spacing; 94, Sixth gap; a, Laser beam. Detailed Implementation
[0029] First, please refer to Figure 1 and Figure 2 As shown, the breathable metal structure with a pore gradient of the present invention includes a first stack 1, which has a first surface and a second surface facing each other. A second stack 2 is bonded to the first surface of the first stack 1, and a third stack 3 is bonded to the second surface of the first stack 1. The first stack 1 has a plurality of first pores 11, the second stack 2 has a plurality of second pores 21, and the third stack 3 has a plurality of third pores 31. The first pores 11 of the first stack 1 are positioned such that... The positions of the second hole 21 in the second stack 2 and the third hole 31 in the third stack 3 are corresponding and connected. The diameter of the second hole 21 is smaller than the diameter of the first hole 11, and the diameter of the third hole 31 is smaller than or equal to the diameter of the first hole 11. The diameter of the first hole 11 in the first stack 1 is greater than 80 micrometers (μm), and the diameter of the second hole 21 in the second stack 2 is less than 50 micrometers. In addition, the diameter of the third hole 31 in the third stack 3 is greater than 80 micrometers or less than 50 micrometers.
[0030] Accordingly, the manufacturing method of the breathable metal structure with pore gradient of the present invention is also provided in the following section. Figure 3 As shown, the implementation steps include:
[0031] A. Creating the first layer 1: Please refer to the following: Figure 4 and Figure 5As shown, metal powder particles are compacted and spread to form a first layer 4. Then, a laser beam a scans the first layer 4 with multiple parallel and spaced first linear paths 41. Each first linear path 41 of the first layer 4 is accompanied by a first melt pool width 42, which is set to 70 micrometers to 150 micrometers. Furthermore, a first line spacing 43 is formed between two adjacent first linear paths 41 of the first layer 4. The distance (denoted by "d" in the attached figure) is greater than the width 42 of the first molten pool of the first linear path 41. The first line spacing 43 of two adjacent first linear paths 41 of the first layer 4 is set to 150 micrometers to 300 micrometers. The difference between the first line spacing 43 and the width 42 of the first molten pool of the first layer 4 forms a first gap 44 (denoted by "g" in the attached figure). The first gap 44 of the first layer 4 is greater than 80 micrometers. Then, metal powder is compactly and evenly spread on the first layer 4 to form a second layer 5. Then, a laser beam a scans several parallel and spaced second linear paths 51 on the second layer 5. The second linear paths 51 of the second layer 5 are set at an angle to the first linear paths 41 of the first layer 4. 51 is accompanied by a second molten pool width 52. The second line spacing 53 formed between two adjacent second linear paths 51 of the second stacked layer 5 is greater than its second molten pool width 52. The difference between the second line spacing 53 and the second molten pool width 52 of the second stacked layer 5 forms a second gap 54. The second molten pool width 52 of the second stacked layer 5 is set to 70 micrometers to 150 micrometers, the second line spacing 53 is set to 150 micrometers to 300 micrometers, and the second gap 54 of the second stacked layer 5 is greater than 80 micrometers. The first gap 44 of the first stacked layer 4 and the second gap 54 of the second stacked layer 5 are arranged in an alternating manner to form a plurality of first holes 11 distributed in a grid pattern. The pore diameter of the first holes 11 is greater than 80 micrometers. The included angle between the alternation of the first gap 44 of the first stacked layer 4 and the second gap 54 of the second stacked layer 5 can be [missing information]. 2nd gap = 1st cos(90-θ), with 90 degrees being optimal. The angle between the first gap 44 and the second gap 54 is complementary. Assuming the tilt angle of the first gap 44 is θ, then the tilt angle of the second gap 54 is 90-θ, where 0<θ<90. Multiple first layers 4 and multiple second layers 5 are stacked sequentially to form a first stack 1 of default thickness, with the first gaps 44 of the first layers 4 and the second gaps 54 of the second layers 5 intersecting to form first holes 11 that correspond to each other, thus forming continuous first holes 11 penetrating the first stack 1.
[0032] B. Creating the second layer 2: Please refer to the following: Figure 6 As shown, metal powder is compactly and evenly spread on the first surface of the first stack 1 to form a third stack 6. Then, a laser beam a scans the third stack 6 with multiple parallel and spaced third linear paths 61. Each third linear path 61 of the third stack 6 is accompanied by a third molten pool width 62, which is set to 70 micrometers to 150 micrometers. Furthermore, the third line spacing 63 formed between two adjacent third linear paths 61 of the third stack 6 is greater than [missing value]. The third molten pool width 62 of the third linear path 61, the third line spacing 63 of the two adjacent third linear paths 61 of the third stacked layer 6 is set to 120 micrometers to 200 micrometers, the difference between the third line spacing 63 and the third molten pool width 62 of the third stacked layer 6 forms a third gap 64, the third gap 64 of the third stacked layer 6 is less than 50 micrometers, and then metal powder is compacted and spread evenly on the third stacked layer 6 to form a fourth stacked layer 7, and then multiple parallel lines are executed on the fourth stacked layer 7 by laser beam a. The scanning of the fourth linear path 71, which is set at intervals, is angled to the third linear path 61 of the third layer 6. The fourth linear path 71 of the fourth layer 7 is accompanied by a fourth molten pool width 72. The fourth line spacing 73 formed between two adjacent fourth linear paths 71 of the fourth layer 7 is greater than the fourth molten pool width 72. The difference between the fourth line spacing 73 and the fourth molten pool width 72 of the fourth layer 7 forms a fourth gap 74. The width 72 of the fourth molten pool of layer 7 is set to 70 micrometers to 150 micrometers, and the fourth line spacing 73 is set to 120 micrometers to 200 micrometers. The fourth gap 74 of the fourth layer 7 is less than 50 micrometers. The third gap 64 of the third layer 6 and the fourth gap 74 of the fourth layer 7 are arranged in an alternating pattern to form a grid-like distribution of multiple second pores 21. The pore diameter of the second pores 21 is less than 50 micrometers. The included angle between the alternation of the third gap 64 of the third layer 6 and the fourth gap 74 of the fourth layer 7 can be [missing information]. 4th gap = 3rd The angle is cos(90-θ), with 90 degrees being optimal. The angle between the third gap 64 and the fourth gap 74 is complementary. Assuming the tilt angle of the third gap 64 is θ, then the tilt angle of the fourth gap 74 is 90-θ, where 0<θ<90. A fourth layer 7 is stacked on a third layer 6 to form a second stack 2 of default thickness. The third gaps 64 of the at least one third layer 6 and the fourth gaps 74 of the at least one fourth layer 7 are staggered to form second holes 21 that correspond to each other, creating continuous second holes 21 penetrating the second stack 2. The position of the second holes 21 of the second stack 2 corresponds to and communicates with the position of the first holes 11 of the first stack 1.
[0033] C. Creating the third layer 3: Please refer to the following: Figure 7 As shown, metal powder is compactly and evenly spread on the second surface of the first stack 1 to form a fifth stack 8. Then, a laser beam a scans the fifth stack 8 with multiple parallel and spaced fifth linear paths 81. Each fifth linear path 81 of the fifth stack 8 is accompanied by a fifth molten pool width 82, which is set to 70 micrometers to 150 micrometers. The fifth line spacing 83 formed between two adjacent fifth linear paths 81 of the fifth stack 8 is greater than the fifth molten pool of the fifth linear path 81. The width is 82. The fifth line spacing 83 formed between two adjacent fifth linear paths 81 of the fifth layer 8 is set to 150 micrometers to 300 micrometers or 120 micrometers to 200 micrometers. The difference between the fifth line spacing 83 and the fifth molten pool width 82 of the fifth layer 8 forms a fifth gap 84. The fifth gap 84 of the fifth layer 8 is greater than 80 micrometers or less than 50 micrometers. Then, metal powder is compacted and spread evenly on the fifth layer 8 to form a sixth layer 9. Then, multiple parallel and spaced lines are executed on the sixth layer 9 by laser beam a. The scanning of the established sixth linear path 91, the sixth linear path 91 of the sixth stacked layer 9 is set at an angle to the fifth linear path 81 of the fifth stacked layer 8, the sixth linear path 91 of the sixth stacked layer 9 is accompanied by a sixth molten pool width 92, the sixth line spacing 93 formed between two adjacent sixth linear paths 91 of the sixth stacked layer 9 is greater than the sixth molten pool width 92, the difference between the sixth line spacing 93 and the sixth molten pool width 92 of the sixth stacked layer 9 forms a sixth gap 94, the sixth molten pool width 92 of the sixth stacked layer 9 is set The spacing between the sixth and sixth layers is 70 to 150 micrometers, and the sixth line spacing 93 is set to 150 to 300 micrometers or 120 to 200 micrometers. The sixth gap 94 of the sixth layer 9 is greater than 80 micrometers or less than 50 micrometers. The fifth gap 84 of the fifth layer 8 and the sixth gap 94 of the sixth layer 9 are arranged in an alternating pattern to form a grid-like distribution of multiple third holes 31. The pore size of the third holes 31 is greater than 80 micrometers or less than 50 micrometers. The included angle between the alternation of the fifth gap 84 of the fifth layer 8 and the sixth gap 94 of the sixth layer 9 can be [missing information]. 6th gap = 5thThe angle is cos(90-θ), with 90 degrees being optimal. The angle between the fifth gap 84 and the sixth gap 94 is complementary. Assuming the tilt angle of the fifth gap 84 is θ, then the tilt angle of the sixth gap 94 is 90-θ, where 0<θ<90. A sixth layer 9 is stacked on a fifth layer 8 to form a third stack 3 of default thickness. The positions of the third holes 31 formed by the interlacing of the fifth gaps 84 of the at least one fifth layer 8 and the sixth gaps 94 of the at least one sixth layer 9 correspond to each other, forming a continuous third hole 31 penetrating the third stack 3, and ensuring that the position of the third hole 31 of the third stack 3 corresponds to the position of the first hole 11 of the first stack 1.
[0034] Therefore, a permeable metal structure with a pore gradient can be easily manufactured using the manufacturing method of the present invention. When the permeable metal with a pore gradient of the present invention is used as a mold, the mold cavity can be set in the second layer 2 with a pore diameter of less than 50 micrometers, so that the product can form a fine and smooth surface quality when it is molded in the mold cavity. The pore diameter of the first hole 11 of the first layer 1 is designed to be greater than 80 micrometers, which helps to dissipate the large amount of gas generated during the injection molding process of the plastic product, thus effectively solving the problem of trapped air accumulation. In addition, the mold exterior... The aperture of the third hole 31 in the third layer 3 on the side can be adjusted to less than 50 micrometers or greater than 80 micrometers according to the product manufacturing requirements, so as to take into account the mechanical strength and venting of the mold. Accordingly, the permeable metal structure design with pore gradient of the present invention can effectively improve the air permeability of the mold, so as to improve the problem of trapped air encountered in the injection molding process of plastic finished products, while ensuring the surface quality of the injection molded product and taking into account the mechanical strength of the mold. After actual measurement, the mechanical strength of the mold made by the present invention can reach Rockwell hardness (HRC) 40-50.
[0035] Furthermore, the manufacturing method of the permeable metal structure with a pore gradient according to the present invention can easily produce permeable metal with the required pore size, shape, and positional distribution, while ensuring the continuity of the pore positions. When used as a mold, the resulting mold has excellent air permeability, preventing any blockage or interruption of venting, and provides good pressure relief during product injection molding and demolding, preventing damage during demolding due to internal and external pressure differences, thereby minimizing the impact of air on the product.
Claims
1. A breathable metal structure with a pore gradient, characterized in that, The device includes a first stack having a first surface and a second surface. A second stack is bonded to the first surface of the first stack. The first stack has a plurality of first holes, and the second stack has a plurality of second holes. The positions of the plurality of first holes in the first stack correspond to and communicate with the positions of the plurality of second holes in the second stack. The diameter of the second holes is smaller than the diameter of the first holes. This permeable metal structure with a pore gradient is applied to a mold to set the cavity in the second stack, so that the plastic product forms a fine and smooth surface during cavity molding. The first holes in the first stack are used to provide for the dissipation of a large amount of gas during the injection molding process of the plastic product, so as to solve the problem of trapped air accumulation.
2. The breathable metal structure with a pore gradient according to claim 1, characterized in that, The diameter of the first pore in the first stack is greater than 80 micrometers, and the diameter of the second pore in the second stack is less than 50 micrometers.
3. The breathable metal structure with a pore gradient according to claim 1, characterized in that, The breathable metal structure with a pore gradient further includes a third layer, which is bonded to the second surface of the first layer. The third layer has a plurality of third pores, the positions of which correspond to and communicate with the positions of the plurality of first pores in the first layer. The diameter of the third pore is less than or equal to the diameter of the first pore.
4. The breathable metal structure with a pore gradient according to claim 3, characterized in that, The diameter of the first hole in the first stack is greater than 80 micrometers, and the diameter of the third hole in the third stack is greater than 80 micrometers or less than 50 micrometers.
5. A method for manufacturing a breathable metal structure with a pore gradient as described in any one of claims 1 to 4, characterized in that, Its implementation steps include: Step A: Fabricating the first layer: Metal powder is compactly and evenly spread to form a first layer. Then, a laser beam is used to scan the first layer with multiple parallel and spaced first linear paths. Each first linear path in the first layer forms a first molten pool width. The first line spacing between two adjacent first linear paths in the first layer is greater than the first molten pool width. The difference between the first line spacing and the first molten pool width forms a first gap. Metal powder is then compactly and evenly spread on the first layer to form a second layer. A laser beam is then used to scan the second layer with multiple parallel and spaced second linear paths. The second linear paths in the second layer are parallel to and spaced from the first linear paths in the first layer. The second linear path of the second stacked layer is accompanied by a second molten pool width. The second line spacing formed between two adjacent second linear paths of the second stacked layer is greater than the second molten pool width. The difference between the second line spacing and the second molten pool width of the second stacked layer forms a second gap. The first gap of the first stacked layer and the second gap of the second stacked layer are arranged in an alternating manner to form a plurality of first holes distributed in a grid. The plurality of first stacked layers and the plurality of second stacked layers are stacked in sequence to form a first stacked layer. The positions of the plurality of first holes formed by the alternating arrangement of the plurality of first stacked layers and the plurality of second stacked layers correspond to each other to form a plurality of continuous first holes that penetrate the first stacked layer. Step B: Fabricating the second layer: Metal powder is compactly spread on the first surface of the first layer to form a third layer. A laser beam is then used to scan the third layer with multiple parallel and spaced third linear paths. Each third linear path in the third layer is accompanied by a third molten pool width. The distance between two adjacent third linear paths in the third layer is greater than the width of the third molten pool. The difference between the distance between the third linear paths and the width of the third molten pool forms a third gap. Metal powder is then compactly spread on the third layer to form a fourth layer. A laser beam is then used to scan the fourth layer with multiple parallel and spaced fourth linear paths. The fourth linear paths in the fourth layer are angled to the third linear paths in the third layer. Each fourth linear path in the fourth layer is accompanied by a fourth molten pool width. The distance between two adjacent fourth linear paths in the fourth layer is greater than the width of the fourth molten pool. The difference between the distance between the fourth linear paths and the width of the third molten pool forms a third gap. The difference in the width of the molten pool forms a fourth gap. The third gap of the third layer and the fourth gap of the fourth layer are arranged in an alternating pattern to form a plurality of second holes distributed in a grid pattern. At least one third layer and at least one fourth layer are stacked sequentially to form a second stack. The positions of the plurality of second holes formed by the alternating at least one third layer and at least one fourth layer correspond to each other, forming a plurality of continuous second holes penetrating the second stack. The positions of the plurality of second holes in the second stack correspond to and communicate with the positions of the plurality of first holes in the first stack. The aperture of the second hole is smaller than the aperture of the first hole. The permeable metal structure with a pore gradient manufactured by this method is applied to a mold to set the cavity in the second stack, so that the plastic product forms a fine and smooth surface when the cavity is formed. The first holes of the first stack are used to provide for the dissipation of a large amount of gas during the injection molding of the plastic product, so as to solve the problem of trapped air accumulation.
6. The method for manufacturing a breathable metal structure with a pore gradient according to claim 5, characterized in that, The width of the first molten pool and the width of the second molten pool of the first stack are 70 micrometers to 150 micrometers, the length of the first line spacing and the second line spacing are 150 micrometers to 300 micrometers, the first gap of the first stack and the second gap of the second stack are greater than 80 micrometers, and the aperture of the first hole formed by the alternation of the first gap of the first stack and the second gap of the second stack is greater than 80 micrometers.
7. The method for manufacturing a breathable metal structure with a pore gradient according to claim 5, characterized in that, The width of the third molten pool and the width of the fourth molten pool of the second stack are 70-150 micrometers, the third line spacing and the fourth line spacing are 120-200 micrometers, the third gap of the third stack and the fourth gap of the fourth stack are less than 50 micrometers, and the aperture of the second hole formed by the interlacing of the third gap of the third stack and the fourth gap of the fourth stack is less than 50 micrometers.
8. The method for manufacturing a breathable metal structure with a pore gradient according to claim 5, characterized in that, The method for manufacturing the breathable metal structure with a pore gradient further includes: To create a third layer, metal powder is compactly spread on the second surface of the first layer to form a fifth layer. A laser beam is then used to scan the fifth layer with multiple parallel and spaced fifth linear paths. Each fifth linear path in the fifth layer forms a fifth molten pool width. The spacing between two adjacent fifth linear paths in the fifth layer is greater than the fifth molten pool width, and the difference between the spacing and the molten pool width forms a fifth gap. Next, metal powder is compactly spread on the fifth layer to form a sixth layer. A laser beam is then used to scan the sixth layer with multiple parallel and spaced sixth linear paths. The sixth linear paths in the sixth layer are angled to the fifth linear paths in the fifth layer, and each sixth linear path in the sixth layer forms a sixth molten pool width. The sixth line spacing formed between two adjacent sixth linear paths is greater than the width of the sixth molten pool. The difference between the sixth line spacing and the width of the sixth molten pool of the sixth stacked layer forms a sixth gap. The fifth gap of the fifth stacked layer and the sixth gap of the sixth stacked layer are arranged in an alternating manner to form a plurality of third holes in a grid-like distribution. At least one fifth stacked layer and at least one sixth stacked layer are stacked in sequence to form a third stacked layer. The positions of the plurality of third holes formed by the alternating arrangement of the at least one fifth stacked layer and at least one sixth stacked layer correspond to each other to form a plurality of continuous third holes penetrating the third stacked layer. The positions of the plurality of third holes in the third stacked layer correspond to and communicate with the positions of the plurality of first holes in the first stacked layer, and the diameter of the third hole is less than or equal to the diameter of the first hole.
9. The method for manufacturing a breathable metal structure with a pore gradient according to claim 8, characterized in that, The width of the fifth molten pool and the width of the sixth molten pool of the third stack are 70 micrometers to 150 micrometers, the fifth line spacing and the sixth line spacing are 150 micrometers to 300 micrometers or 120 micrometers to 200 micrometers, the fifth gap of the fifth stack and the sixth gap of the sixth stack are greater than 80 micrometers or less than 50 micrometers, and the aperture of the third hole formed by the interlacing of the fifth gap of the fifth stack and the sixth gap of the sixth stack is greater than 80 micrometers or less than 50 micrometers.
10. The method for manufacturing a breathable metal structure with a pore gradient according to claim 9, characterized in that, The included angle between the first gap and the second gap in the first stack is . 2nd gap= 1st cos(90-θ), the included angle between the third and fourth gaps of the second stack is... 4th gap= 3rd cos(90-θ), the included angle between the fifth and sixth gaps of the third stack is... 6th gap= 5th cos(90-θ); where the tilt angle of the first gap is θ, the tilt angle of the second gap is 90-θ, 0<θ<90; the tilt angle of the third gap is θ, the tilt angle of the fourth gap is 90-θ, 0<θ<90; the tilt angle of the fifth gap is θ, and the tilt angle of the sixth gap is 90-θ, 0<θ<90.