Interlocking material

Abstract

The method includes manufacturing the interlocking volume using a three-dimensional additive manufacturing process, wherein using the additive manufacturing process includes depositing successive layers, each layer including a first material distributed according to a first interlocking material pattern 24 and a second material distributed according to a second interlocking material pattern 18, wherein the second material is different from the first material.

Description

Technical Field

[0001] Cross-Reference to Related Applications This application claims the benefit of U.S. Patent Application Serial No. 17 / 082,784, filed on October 28, 2020, the content of which is incorporated herein by reference.

[0002] The present invention relates to an additive manufacturing process based on material jetting "inkjet" technology. Background Art

[0003] Additive manufacturing enables the fabrication of objects by the selective addition of material. A typical additive manufacturing process is performed by slicing a digital model into data representing a series of layers. Such a model is generally represented as an "STL" file.

[0004] The data representing the plurality of layers is sent to a manufacturing apparatus. Using the data, the manufacturing apparatus deposits physical layers one by one from bottom to top.

[0005] Material jetting "inkjet 3D printing" is an additive manufacturing method in which a print head deposits droplets of a printable material, and the printable material is sometimes referred to as "ink". A typical printer used for such printing includes one or more print heads mounted on a gantry, and is capable of depositing a printable liquid matrix material at different locations within a "build volume". The printable liquid matrix material is solidified by irradiation with UV or visible light.

[0006] In some of these printers, the print head moves during the printing process. In some other printers, the object to be manufactured is placed on a movable "build platform" that moves relative to the print head.

[0007] Certain types of printers can construct objects made of two or more different materials. To achieve this, such printers typically use different print heads to deposit different materials. This results in a composite heterogeneous structure having different parts made of different materials. Such objects are referred to herein as "multi-material objects." These are called multi-material objects. These multi-material objects can be represented by a series of three-dimensional models, each model representing one type of material. These different materials are generally selected because they have different material properties. For example, one material may be hard, while another is flexible or soft. These different materials often do not naturally adhere to each other. As a result, the composite structure is at risk of delamination along the boundaries between the different materials. The adhesion properties of these surfaces must be considered, which limits the choice of materials. [Overview of the project] [Means for solving the problem]

[0008] In multi-material objects, the surfaces where two different materials come into contact with each other are called "material interfaces." The shape and topology of these material interfaces can be configured to create interlocking patterns that generate strong mechanical bonds between the materials. These mechanical bonds compensate for the ineffectiveness of chemical bonding.

[0009] In a general embodiment of the present invention, the method includes manufacturing an interlocking volume using a three-dimensional additive manufacturing process. In such a method, the use of an additive manufacturing process includes depositing a series of layers, each layer comprising a first material distributed according to a first interlocking material pattern and a second material distributed according to a second interlocking material pattern, wherein the second material is different from the first material.

[0010] In some embodiments of this method, the distribution of the second material is complementary to the distribution of the first material. As a result, the portion of the interlocking volume not filled by the first material is filled by the second material, and the portion not filled by the second material is filled by the first material.

[0011] The methods and structures described herein are particularly useful for materials that do not naturally adhere well to each other. Examples include epoxy and acrylates, which only weakly adhere to each other.

[0012] In some embodiments of this method, the interlocking volume includes a set of first interlocking structures and a set of second interlocking structures formed from first and second materials, respectively. In such embodiments, the spatial distribution of the interlocking structures in the set of first and second interlocking structures is based on the corresponding first and second interlocking material patterns.

[0013] Furthermore, other embodiments of this method include forming an interlocking structure in a boundary region defined by an arbitrary function of two variables. Among these, there are embodiments in which the function defines a plane, in which case the boundary region has a uniformly flat surface. For simplicity of explanation, the drawings described herein show a material interface that is a uniformly flat surface. However, the interlocking patterns described herein can be parameterically extended to support curved material interfaces.

[0014] In some embodiments of this method, each interlocking structure in the first set forms a toroidal element having a central hole diameter and a toroidal diameter. These diameters are determined based on first material information and second material information, which include information about the first material and the second material, respectively.

[0015] In some embodiments of this method, each interlocking structure in the first one or both of the above diameters is modified to distort, shift, or deform the overall shape of the interlocking structure.

[0016] An alternative embodiment of this method includes the step of manufacturing the first material volume section and the second material volume section such that the interlocking volume section is located between the first material volume section and the second material volume section.

[0017] Furthermore, in embodiments of this method, each interlocking structure in the first set includes a reinforcing region located at the interface between the interlocking structure and the region of the first material. Some of these embodiments include making the reinforcing region circular or substantially circular.

[0018] In another aspect of the present invention, a product formed by three-dimensional additive manufacturing comprises a first volume section manufactured from a first material, a second volume section manufactured from a second material, and a transition volume section. Within the transition volume section are pairs of first and second interlocking structures. The first pair of interlocking structures is integrated with a first region and manufactured from the first material. The second pair of interlocking structures is integrated with a second volume section and manufactured from the second material. Each interlocking structure from the first pair is connected to at least one interlocking structure from the second pair. As a result, the first and second pairs of interlocking structures cooperate to mechanically connect the first and second volume sections of the object.

[0019] In some embodiments, the first set of interlocking structures forms a closed loop. Among these embodiments, there are embodiments in which the closed loop has a toroidal shape.

[0020] Other embodiments include embodiments in which each of the first number of interlocking structures has a central hole diameter and a toroidal ring diameter. These diameters can be modified together or independently depending on the application.

[0021] In yet another embodiment, each interlocking structure in the first set includes a rounded reinforcing structure positioned at the interface between the interlocking structure and the first region. Some of these embodiments include a base portion of the reinforcing structure.

[0022] Another embodiment of this product features a third set of interlocking structures. Each interlocking structure in the third set is connected to either the first set or the second set of interlocking structures.

[0023] In other embodiments, the present invention is characterized by manufacturing an object having first and second volumetric sections made of corresponding materials from among first and second materials that are different from each other, using an additive manufacturing process. In such cases, using an additive manufacturing process includes forming projections from the first material, which protrude into and engage with the second material so as to resist tensile and shear forces on the object.

[0024] Embodiments of this method include embodiments in which forming a projection involves forming a toroid that protrudes from a first volume portion into a second volume portion, and embodiments in which forming a projection involves forming a hook that protrudes into the second volume portion.

[0025] Furthermore, these embodiments include embodiments in which forming a projection is greater than 0, i.e., forming a connected and oriented surface having a topological genus of 1 or more, and embodiments in which forming a projection is greater than 0, i.e., forming a connected and oriented surface having a topological genus equal to 1.

[0026] In some embodiments of this method, forming the protrusion includes depositing a first layer, a second layer, and a third layer, each layer includes a first portion made of a first material, a second portion made of a second material, and a third portion between the first portion and the second portion. The third portion of the first layer has a first region and a second region, the first region and the second region are each made of the first material and surrounded by the second material. The third portion of the second layer has a first region and a second region, the first region and the second region are each made of the first material and surrounded by the second material. The third portion of the third layer includes a region made of the first material and surrounded by the second material, the region at least partially overlaps with the first region and the second region of the second layer, and the first region and the second region of the first layer and the second layer, and the region of the third layer constitute one component of the protrusion.

[0027] As another advantage of the present invention, materials that are difficult to bond without using a conventional adhesive can be bonded without using an adhesive.

[0028] Compared with conventional additive manufacturing processes, the present invention can reliably bond materials that may not maintain a bonded state when printed adjacent to each other (for example, due to weak mechanical bonding force).

[0029] Other features and advantages of the present invention will be apparent from the following description and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] [Figure 1] Figure 1 is a perspective view of an object manufactured using an additive manufacturing process, the object having an interface between two portions made of different materials. [Figure 2] Figure 2 is a diagram showing one of a plurality of protrusions protruding from a first volume portion to a second volume portion, which cooperate to connect the two portions shown in Figure 1. [Figure 3] Figure 3 is a diagram showing a skirt portion that smoothens the space between the first volume portion and the protrusion shown in Figure 2. [Figure 4]Figure 4 shows a set of protrusions of the type shown in Figure 3, arranged to form a rectangular array. [Figure 5] Figure 5 shows a cross-section of the linear arrangement of the protrusions shown in Figure 4. [Figure 6] Figure 6 shows a cross-section of the linear arrangement of the protrusions shown in Figure 4. [Figure 7] Figure 7 shows the distribution of the tails corresponding to the arrangement shown in Figure 4. [Figure 8] Figure 8 shows the distribution of tails where the tails of adjacent rows are offset by half the pitch between the tails. [Figure 9] Figure 9 shows an arrangement of protrusions similar to the arrangement shown in Figure 4, where the tails of adjacent rows are distributed to form a hexagonal arrangement that is offset by half the pitch between the tails. [Figure 10] Figure 10 shows an arrangement of protrusions similar to that shown in Figure 4, but with protrusions of different sizes representing different hierarchical levels. [Figure 11] Figure 11 is a perspective view of the same arrangement of protrusions as shown in Figure 4, but in a state where the protrusions do not form a loop. [Figure 12] Figure 12 is a perspective view of a similar arrangement of protrusions as shown in Figure 17, but with protrusions having pyramidal tips instead of spherical tips. [Figure 13] Figure 13 is a cross-sectional view of the projection shown in Figure 12. [Modes for carrying out the invention]

[0031] Figure 1 shows an object 10 manufactured using a three-dimensional additive manufacturing process. Such a process involves depositing one layer of material at a time according to a "build plan." Each layer may consist of one or more materials.

[0032] Object 10 includes a first volume portion 12 and a second volume portion 14. The first volume portion 12 contains a first material 16. The second volume portion 14 contains a second material 18 that is different from the first material 16. In a typical embodiment, the first material 16 is a soft material and the second material 18 is a hard material.

[0033] The first and second volume sections 12 and 14 are in contact at a flat interface 20. The portion of the second volume section 14 adjacent to the interface 20 defines a transition volume section 22, or "interlocking volume." Within this transition volume section 22 are interlocking projections 24 (hidden), which operate to connect the first and second volume sections 12 and 14. These interlocking projections 24 protrude from the first volume section 12 into the second material 18. The projections 24 thus define an "interlocking structure." The projections 24 are hidden and not visible in Figure 1. However, examples of the projections 24 can be seen in Figures 2 and 3.

[0034] As shown in Figures 2 and 3, such projections 24 are each integrated with the first volume portion 12. Therefore, the projections 24 are formed from the first material 16.

[0035] The projection 24 includes a toroidal portion 26 and a hole 28. In some examples, the hole 28 is substantially circular. In the illustrated embodiment, the hole 28 is defined by the toroidal portion 26 and the first volume portion 12. In other examples, the toroidal portion 26 completely defines the hole 28.

[0036] In Figure 2, the toroidal portion 26 has a pair of root portions 30 protruding from the first volume portion 12. Both sides of the toroidal portion 26 extend from the corresponding root portions 30. The joint between the root portions 30 and the toroidal portion 26 forms an edge. This edge is susceptible to mechanical stress.

[0037] Figure 3 shows the projection 24, where the base portion 32 reinforces the root portion 30 shown in Figure 2. Without the base portion 32, the part where the toroidal portion 26 contacts the root portion 30 would have a sharp corner, but the base portion 32 eliminates this. Therefore, the base portion 32 distributes its mechanical stress over a larger area, thereby eliminating areas that are susceptible to mechanical stress. As a result, the projection 24 becomes less prone to fracture.

[0038] In Figures 2 and 3, a closed loop is formed between the toroidal portion 26 and the interface 20. This loop surrounds a portion of the second volume 14. This surrounded portion is integrated with the portion of the second volume 14 that is not surrounded by the projection 24. Topologically, these surrounded portions of the second volume 14 also form a closed loop projecting from the second volume 14 into the transition volume 22. However, the resulting loop does not need to have the same shape as that defined by the projection 24. In addition, the multiple structures within the transition volume 22 cooperate to resist both a first force and a second force that is lateral to the first force. The first force acts in a direction that separates the first and second volume 12, 14. This is referred to herein as the "longitudinal force." The second force causes the first and second volume 12 and 2 to slide relative to each other. This second force is called a "lateral force" or "shear force."

[0039] During manufacturing, the shapes of the toroidal portion 26, the hole 28, and the base portion 32 can be parameterized independently. Parameterization is based on the material properties of the first and second materials, or a comparison of these properties. Examples of such material properties include tensile strength and shear strength.

[0040] In this manufacturing process, the print head moves to different positions on a plane and injects the first and second materials 16 and 18 onto the plane. As a result, layers are formed. In doing so, the print head forms protrusions 24 by laying layers having a specific spatial distribution of the first and second materials 16 and 18 in the transfer volume 22. By having each layer have a slightly different spatial distribution of the first and second materials 16 and 18, it becomes possible to form three-dimensional protrusions 24 within the transfer volume 22. The spatial distribution of the first and second materials 16 and 18 is referred to as the first and second "interlocking material patterns".

[0041] In the case of the toroidal projection 24, some of the multiple layers feature two regions made of the first material 16. These two regions have a cross-section passing through the toroidal projection 24. As the projection is constructed layer by layer, these two regions approach each other until they merge into a single region toward the most distal part of the projection 24.

[0042] Each of these protrusions 24 is made from the first material 16. In the embodiments shown in Figures 2 and 3, each protrusion 24 forms a closed loop that surrounds a portion of the second volume 14 while remaining connected to the first volume 12. As a result, the protrusions 24 surround a portion of the second material 18. By having multiple such protrusions 24, the first and second materials 16 and 18 can be securely joined together.

[0043] The strength of the bond between the first and second materials 16 and 18 obtained thereby is determined, at least in part, based on the tensile strength of each material 16 and 18. This technique is particularly useful when the materials 16 and 18 are dissimilar in their mechanical properties.

[0044] For example, if the object 10 to be manufactured is a shoe, the first region may be the outsole of the shoe, and the second region may be the midsole of the shoe. Therefore, the first material 16 may be a soft material for the sole, and the second material 18 may be a harder material with higher rigidity used for the midsole of the shoe. These are usually difficult to join together without using adhesive.

[0045] In conventional additive manufacturing processes, the first and second materials 16 and 18 can simply be printed side by side. However, this does not guarantee a good connection. After all, dissimilar materials do not always have good mechanical bonding strength. However, since at least one of the materials has high tensile strength, it is possible to join them using multiple protrusions 24 in the additive manufacturing process.

[0046] Typically, the thicknesses of the first and second volumetric sections 12 and 14 are optimized to achieve specific design objectives. For example, in shoes, the outsole should be thick enough to have an acceptable wear life, but not so thick that it becomes a burden to lift with each step. A further advantage of the projection 24 described here is that the transition volumetric section 22 can be kept very small.

[0047] Figure 3 shows a single projection 24 in which each hem portion 32 is integrated with one end of the toroidal portion 26 of the projection. However, in reality, as shown in Figure 4, there will be many such toroidal portions 26. As shown in Figure 4, having multiple projections 24 allows the first and second volume portions 12 and 14 to be joined more effectively.

[0048] Figure 4 shows a specific arrangement of the projections 24 in which two or more toroidal portions 26 of two or more projections 24 originate from the same base 32. This allows for an arrangement of interlocks 24 that form a rectangular array. Figures 5 and 6 show selected portions of the rectangular array as shown in Figure 4.

[0049] Figure 7 shows the distribution of the tail portions 32 that can be obtained to obtain the rectangular arrangement shown in Figure 4. This rectangular arrangement is characterized by tail column 34 and tail row 36.

[0050] Each toroidal section 26 has a first end arising from a first hem 32 and a second end arising from a second hem 32. The first and second hems are in the same hem row 34 or the same hem row 36. As a result, there are no diagonal connections in Figure 4. Similarly, it can be said that there are no toroidal sections 26 having a first end arising from a first hem and a second end arising from a second hem that is not in the same row 34 or row 36 as the first hem.

[0051] Figure 8 is similar to that shown in Figure 7, but shows the distribution of the hems 32, where each hem row 36 is offset by the radius of the hem. Furthermore, by moving the rows 36 closer together, each hem 32 contacts the maximum number of adjacent hems 32 without overlapping. Preferably, the rows 36 are moved closer together by a coefficient equal to the sine of 60 degrees. Each hem 32 inside the array of hems 32 is adjacent to the other six hems 32. This arrangement is characterized by a more compact distribution of the projections 24, where the toroidal portion 26 takes on a hexagonal configuration, as shown in Figure 9.

[0052] Generally, it is useful to arrange the interface 20 to accommodate as many interlocks 24 as possible. This is achieved by arranging the interlocks 24 in a two-dimensional array, as shown in the embodiments in Figures 4 and 9. These are useful when the flat interface 20 has an aspect ratio that can accommodate the two-dimensional array. The length of the flat interface 20 may be much greater than its height. As a result, accommodating a two-dimensional array is not practical. Such embodiments feature a one-dimensional array of projections 24.

[0053] In the embodiments described so far, each hem portion 32 is connected to its adjacent hem portion 32 by a toroidal portion 26. However, this is by no means a necessary condition. The distribution of the toroidal portions 26 depends on other factors, and it is not necessary to have two or more toroidal portions 26 sharing the same hem portion 32.

[0054] The embodiments described so far are characterized by holes 28 distributed in a single layer. However, in the alternative embodiment shown in Figure 10, the holes 28 occupy two layers. This arrangement makes it possible to connect the first and second volume sections 12 and 14 at more locations.

[0055] In another embodiment shown in Figure 10, the protrusions 24 are of different sizes. This arrangement allows for spatially variable bonding strength between the first and second volume sections 12 and 14.

[0056] The projections disclosed herein have a structure that includes one or more holes. However, some embodiments have projections 24 that do not have holes. An example of such a projection 24 is a shaft 44 with a large distal tip 46, as shown in Figure 11. The large distal tip 46 is ultimately incorporated into a corresponding recess formed in the second volume 14 during the additive manufacturing process.

[0057] Figure 11 shows an embodiment in which the large distal tip portion 46 is spherical in shape. Figures 12 and 13 show embodiments in which the large distal tip portion 46 is in the shape of an inverted pyramid.

[0058] Many embodiments of the present invention have been described. However, it should be understood that the above description is for illustrative purposes only and does not limit the scope of the invention as defined by the following claims. Therefore, other embodiments are also included in the following claims. For example, the interlocking structure described herein and shown in the drawings is a toroidal projection. However, other structures, including open-loop and hook-shaped structures, are also understood to be within the scope of the invention. Furthermore, various other modifications can be made without departing from the scope of the invention. Moreover, some of the steps described above do not have to be in a specific order and can therefore be performed in an order different from the order described.

Claims

1. A method for manufacturing an interlocking volume using a three-dimensional additive manufacturing process, Using the aforementioned additive manufacturing process involves depositing continuous layers, At least a portion of the continuous layers includes a first material distributed according to a first interlocking material pattern and a second material distributed according to a second interlocking material pattern. The second material differs from the first material, The interlocking volume includes a first interlocking structure formed from the first material and a second interlocking structure formed from the second material. A method for depositing the continuous layers, comprising depositing the first interlocking structure and the second interlocking structure such that they each form a closed loop having a toroidal portion and a hole.

2. The method according to claim 1, wherein the interlocking volume comprises a plurality of first interlocking structures formed from the first material and a plurality of second interlocking structures formed from the second material.

3. The method according to claim 2, wherein the plurality of first interlocking structures are based on the first interlocking material pattern, and the plurality of second interlocking structures are based on the second interlocking material pattern.

4. The method according to claim 1, wherein the first and second interlocking structures are manufactured on a uniform flat surface.

5. The method according to claim 1, wherein the first and second interlocking structures are manufactured on a surface that is deviated from a flat state.

6. The method according to claim 2, wherein each of the plurality of first interlocking structures includes the closed loop, the closed loop comprises a central hole diameter and a toroidal radius, and the dimensions of the central hole diameter and the toroidal radius of each interlocking structure are determined based on first material information and second material information.

7. The invention further comprises manufacturing a first material volume section and a second material volume section. The method according to claim 2, wherein the interlocking volume section is disposed between the first material volume section and the second material volume section.

8. The invention further comprises manufacturing a reinforcing region for each of the plurality of first interlocking structures, The method according to claim 2, wherein the reinforcing region is located at the interface where the interlocking structure is in contact with the first material region.

9. The method according to claim 8, wherein the reinforced region has a substantially circular cross-section.

10. The method according to claim 6, wherein for each of the plurality of first interlocking structures, one or both of the center hole diameter and the toroidal radius are modified to achieve distortion, shift, or deformation of the overall shape of the interlocking structure.

11. A product formed by three-dimensional additive manufacturing, A first volumetric portion manufactured from a first material, A second volumetric portion manufactured from a second material, A transition volume section comprising a plurality of first interlocking structures connected to the first volume section and manufactured from the first material, and a plurality of second interlocking structures connected to the second volume section and manufactured from the second material, Equipped with, The plurality of first interlocking structures are connected to at least one of the plurality of second interlocking structures, and the first and plurality of second interlocking structures form a mechanical connection between the first volume portion and the second volume portion of the product. A manufactured product in which the first interlocking structure and the second interlocking structure each form a closed loop having a toroidal portion and a hole.

12. The product according to claim 11, wherein each closed loop of the interlocking structure has a central hole diameter and a toroidal ring diameter.

13. The product according to claim 12, wherein the size of at least one of the central hole diameter and the toroidal ring diameter is selected based on the material properties of the first and second materials, and the material properties are selected from the group consisting of tensile strength and shear strength.

14. The product according to claim 13, wherein the interlocking structure has different diameters for the central hole and / or the toroidal ring.

15. The product according to claim 11, wherein each of the plurality of first interlocking structures includes a rounded reinforcing structure disposed at the interface between the interlocking structure and the first volume.

16. It further includes multiple third interlocking structures, The product according to claim 11, wherein each of the plurality of third interlocking structures is connected to the interlocking structure of the plurality of first interlocking structures or the interlocking structure of the plurality of second interlocking structures.

17. A method comprising manufacturing an object having first and second volumetric sections made of corresponding materials from among mutually different first and second materials, using an additive manufacturing process, A method comprising using the additive manufacturing process, comprising forming a projection from the first material, the projection protruding into the second material and engaging with the second material so as to resist tensile and shear forces on the object, and the projection being deposited such that it forms a closed loop having a toroidal portion and a hole.

18. The method according to claim 17, wherein the deposition of the protrusions comprises forming an orientable surface connected to the closed loop, the surface having a topological genus greater than 0.

19. The method according to claim 17, wherein depositing the protrusions comprises forming a connected and oriented surface having topological genus 1.

20. The product according to claim 11, wherein at least one of the plurality of first interlocking structures includes a reinforcing region located at the interface where the interlocking structures from the plurality of first interlocking structures are in contact with the first volume.

21. The product according to claim 20, wherein the reinforced region has a circular cross-section.

22. The product according to claim 13, wherein one or both of the central hole diameter and the toroidal ring diameter are selected to achieve distortion, shift, or deformation of the overall shape of the interlocking structure.

23. The product according to claim 11, wherein the plurality of first interlocking structures include projections formed from the first material that protrude into the second material and engage with the second material so as to resist tensile and shear forces on the product.

24. The product according to claim 23, wherein at least one of the interlocking structures is in the form of an annular body.

25. The product according to claim 23, wherein each of the interlocking structures is in the form of an orientable surface connected to the closed loop, and the surface has a topological genus greater than 0.

26. The product according to claim 23, wherein each of the plurality of first and plurality of second interlocking structures includes an interlocking structure which is a form of connected and oriented surface having topological genus 1.

27. The product according to claim 11, wherein the transition volume portion includes a second material which is arranged in the transition volume portion to quantitatively supplement the first material, and as a result, the portion of the transition volume portion not filled with the first material is filled with the second material, and conversely, the portion of the transition volume portion not filled with the second material is filled with the first material.

28. The manufactured product according to claim 11, wherein the transfer volume portion is made of a solid material.

29. The product according to claim 11, wherein each of the first interlocking structures comprises a continuous layer of the first material, and each of the second interlocking structures comprises a continuous layer of the second material.

30. The product according to claim 11, wherein each of the first, second, and third volumetric portions comprises a continuous layer containing both the first material and the second material.

31. It further includes multiple third interlocking structures, The product according to claim 11, wherein each of the plurality of third interlocking structures is connected to the interlocking structures of the plurality of second interlocking structures.

Images