3D printed structure

Abstract

A 3D printed structure of an elastic material having at least a first wall and a second wall, the 3D printed structure comprising: at least a first layer having a first wall portion and a second wall portion, wherein the first wall portion comprises at least a first structural layer in the first wall, the second wall portion in the first layer comprising a first pliable layer; at least a second layer having at least a first wall portion and a second wall portion, wherein the first wall portion comprises a second pliable layer in the second layer, wherein the first structural layer has a first stiffness and the first pliable layer has a second stiffness, wherein the first stiffness is greater than the second stiffness.

Description

Technical Field

[0001] A 3D printed structure of an elastic material having at least a first wall and a second wall, the 3D printed structure comprising: at least a first layer having a first wall portion and a second wall portion, wherein the first wall portion includes at least a primary structural layer in the first layer. Background Technology

[0002] A common problem with 3D printed structures is that these types of structures are typically made of relatively hard materials, which means that the structure of a 3D printed structure may be relatively non-flexible due to the composition of the materials used for printing.

[0003] CN 105034361 discloses a honeycomb core containing cells of different thicknesses and shapes, wherein at least a portion of the wall thickness of the obtained honeycomb cells gradually increases in the direction from the center of the honeycomb cells toward both ends of the honeycomb cells, allowing for the addition of honeycomb clamps. The contact area between the core and the panel, as well as the honeycomb core, can be a flat or curved structure to meet the requirements of nonlinear bending structures, wherein the honeycomb core exhibits excellent bending and compression resistance.

[0004] EP 3 213 909 discloses an impact-resistant sandwich structure framework for a structure resistant to high-speed impacts, comprising a sandwich skin that encapsulates a sandwich core formed by a plurality of spacer layers and a plurality of trigger layers, wherein these layers are alternately stacked in the core.

[0005] These types of materials are widely used in the aerospace industry to provide stiffening effects, whereby these materials are designed to maintain their shape during the application of external forces.

[0006] However, in an attempt to obtain structures that are both compressible and flexible, numerous attempts have been made to construct materials that maintain structural integrity while possessing the desired flexibility. Due to the flexibility and weight of the materials used for printing, constructing layered structures that allow for controlled flexibility and reaction forces in multiple distinct and very specific regions can be a challenging task. Further difficulties may arise when multiple regions within a 3D-printed structure require different levels of flexibility or reaction forces.

[0007] Such flexible layers are typically made from foam-like materials such as PU foam, which can maintain a certain shape while still retaining a degree of flexibility, as seen in applications like seat cushions, shoe midsoles, and luggage pads. One problem with this type of flexible layer is that as the structural strength of the material increases, the layer's flexibility decreases, which in turn increases the material's weight. Furthermore, the formation of this material is usually done in large molds, where any personalization, such as custom contouring, typically requires cutting the material, and the foam needs to be sculpted after manufacturing. Since personalized molds are too expensive, this is not a feasible option for individual customization for every user.

[0008] Therefore, there is a need for improved structures for the customization of flexible structures. Summary of the Invention

[0009] According to this specification, a 3D-printed structure of an elastic material is provided, having at least a first wall and a second wall, the first wall and the second wall being configured to deform when a force is applied to the first wall and / or the second wall in a direction of a first axis, and being configured to return to its original shape when the applied force is released. The 3D-printed structure includes: at least a first layer having a first wall portion and a second wall portion, wherein the first wall portion includes at least a first-level structural layer in the first layer, the second wall portion in the first layer including a first flexible layer, and at least a second layer having at least a first wall portion and a second wall portion, wherein the first wall portion in the second layer includes a second flexible layer, wherein the first-level structural layer has a first stiffness, and the first flexible layer has a second stiffness, wherein the first stiffness is greater than the second stiffness.

[0010] This means that the first layer of the 3D printed structure has a different structure than the second layer. The walls of the 3D printed structure can extend along a first axis, while the second wall can be positioned to the side of the first wall, i.e., in a direction perpendicular to the first axis. Within the meaning of this application, the second axis can be orthogonal to the first axis. Therefore, the 3D printed structure can have multiple layers with varying structures in at least two directions, wherein the structure of the first wall portion and the second wall portion, or any subsequent wall portion, can be repeated in different parts of the 3D printed structure. This can mean that the structure of the first wall portion and the second wall portion can be repeated in the direction of the first axis and / or the direction of the second axis to provide multiple walls and / or multiple layers to provide a 3D structure with a specific stiffness, which can be a combination of structural layers and flexible layers in one or more walls or wall portions of the 3D structure.

[0011] In the context of this specification, the term stiffness can be understood as a flexibility ratio, which can be measured by the stiffness, yield rate, or hardness of a layer (i.e., in this understanding, a harder layer has a higher stiffness ratio compared to a softer layer). The stiffness of a layer should be understood as the ability, potential, or likelihood of a layer to flex in a certain direction. An alternative representation of stiffness may be, for example, the flexibility of a layer, where a first-level structural layer (or any subsequent structural layer) may have a first level of flexibility, while a first and / or second flexible layer (or any subsequent flexible layer) may have a second level of flexibility, where the first level of flexibility may be lower than the second level of flexibility. Stiffness can be viewed as a quantification of the degree to which a layer resists deformation in response to an applied force. The term flexibility can be a complementary concept to stiffness, i.e., the more flexible a layer is, the less stiff it is.

[0012] In the context of this application, when a portion of the wall is disclosed, the term "wall" may be replaced by "the portion of the wall".

[0013] Within the understanding of this application, the term "layer" can be understood as a two-dimensional plane of a three-dimensional structure. A layer may include one or more walls intersecting the two-dimensional plane. Within the understanding of this application, "wall" can be understood as a two-dimensional plane of a three-dimensional structure, wherein the two-dimensional plane may be parallel to the wall and may intersect with multiple layers of the three-dimensional structure. Within the understanding of this application, a first layer of a wall may be adjacent to a second layer of a wall, and a second layer may be adjacent to a third layer of a wall. Therefore, a wall can be considered as a structure having two or more layers stacked on top of or beneath each other.

[0014] The term "structural layer" is intended to distinguish it from other layers in the wall structure, and the term "flexible layer" is intended to name a layer that is not considered a structural layer, so as to distinguish the structural layer from the different layers in the wall structure, namely the flexible layer. The presence of a structural layer and at least one flexible layer in the wall structure does not exclude other types of layers in the wall structure that have different properties from the two layers defined as structural layer and / or flexible layer.

[0015] The first, second, third, or any other structural layer may have a first stiffness. All structural layers may have a first stiffness, wherein the first stiffness is higher than a second stiffness. The first, second, third, and / or any other subsequent flexible layer may have a second flexibility, wherein the second flexibility may be lower than the first flexibility.

[0016] In one embodiment, all structural layers in one and / or multiple walls may have the same flexibility. In another embodiment, all flexible layers in one and / or multiple walls may have the same flexibility.

[0017] Providing a first wall made of an elastic material means that when a force is applied to the wall along the direction of the first axis, the wall can absorb the force that would cause the wall to collapse. This force can be considered a compressive force, where forces below a predetermined level can cause the first wall to compress without deforming away from the first axis. That is, the wall can maintain its shape up to a certain amount of force. However, when a predetermined threshold of force is exceeded, i.e., when a force higher than this threshold is applied to the wall, the wall may deform and detach from its shape, such that one or more layers of the wall may be displaced in a direction different from the direction of the first axis, i.e., in a direction that can be considered, for example, or orthogonal to the first axis. Thus, the wall can be considered to be bending or bulging away from the first axis, where the force applied to the first wall is absorbed in the wall structure due to the elasticity of the elastic material, such that when the force is released / removed from the first wall, the first wall will return to its original shape. That is, the elastic material will provide an elastic wall structure, where the wall will return to its original shape after being compressed. Therefore, the first wall or any subsequent wall can be considered elastic. The wall can be considered to have an uncompressed state, a compressed state, and an intermediate state. The intermediate state can be considered as a wall state in which a compressive force is applied to the wall, but the wall has not yet reached its fully compressed state.

[0018] The wall may have a first end and a second end, the first end being considered the top of the wall and the second end being considered the bottom of the wall, wherein the wall is provided with multiple layers between the first end and the second end. When no compressive force is applied to the wall, the wall may have a first length, wherein the first length is substantially the sum of the heights of each layer of the wall. When a compressive force is applied to the wall in a direction parallel to a first axis, the wall may have a second height, wherein the second height is less than the sum of the heights of each layer.

[0019] This means that the walls of a 3D-printed structure can have regions with higher stiffness in the direction of the first axis than other regions located elsewhere along the first axis. Higher stiffness allows the first-level structural layers or any other structural layers of the first wall to be less likely to deform compared to flexible layers with reduced stiffness. Therefore, this means that when a compressive force is applied to the wall (in the direction of the first axis), if the compressive force is higher than a predetermined force, the compressive force applied to these layers will compress the wall, and the wall will have a tendency to yield to the compressive force, whereby the wall is buckled or bent due to the compressive force. Because the different layers have different stiffnesses, the compressive force will cause layers with lower stiffness to yield before layers with increased stiffness, meaning that bending and / or buckling of the wall will occur in predetermined regions, where layers with lower stiffness will deviate from the first axis before layers with increased stiffness.

[0020] The stiffness and number of layers can be adjusted according to the requirements of the 3D printed structure. For walls with lower requirements on the force needed to allow the first wall to yield, the number of flexible layers can be increased, while to improve resistance to compressive forces, the number of structural layers can be increased. Therefore, the stiffness of the first wall can be changed by altering the ratio of flexible layers to structural layers.

[0021] In one exemplary embodiment of this application, the 3D-printed structure can be a 3D-printed flexible structure. The 3D-printed structure can be considered a shock-absorbing structure, wherein the 3D-printed structure is configured to absorb forces applied to it. Shock absorption can be provided in the form of energy absorbed by the forces applied to the 3D-printed structure, wherein the 3D-printed structure can elastically deform to absorb energy. When the force is released, the energy can be released when the elastic deformation reverses.

[0022] The 3D printer structure and the walls of the 3D printed structure may have an original shape that can be understood as their permanent shape, and a deformable shape that can be regarded as a temporary shape, wherein the deformable shape can be regarded as a shape generated by external stimuli such as external forces or externally applied mechanical energy on the 3D printed structure and / or parts of the 3D printed structure.

[0023] In one embodiment of this application, the 3D-printed structure can be a 3D-printed structure suitable for absorbing forces generated by the human body. The 3D-printed structure can be used as a damping structure, i.e., a rigid structure, between a part of the human body and another entity, such as a portion of the sole assembly in a shoe, a seating area on a chair, a pad between a backpack and the user's body, a mattress, and similar structures that can be used to absorb and distribute energy transferred from the human body to another entity.

[0024] Within the understanding of this application, the term "elastic material" should be understood as referring to an elastic material that can be stretched or compressed without plastic deformation. That is, the elastic region of the stress-strain curve is larger than the plastic region of the stress-strain curve. Specifically, the Young's modulus of the material may be less than 60 GPa, or preferably less than 40 GPa, or less than 20 GPa, or less than 10 GPa.

[0025] The term "elastic material" can refer to a material having an elongation of at least 50%, or specifically greater than 100%, or specifically greater than 200%, or specifically greater than 300%. The term percentage elongation (elongation %) is a measure used to capture the amount of plastic and elastic deformation a material undergoes until it breaks. Percentage elongation is a method for measuring and quantifying the ductility of a material. The final length of the material is compared to its original length to determine the percentage elongation and the material's ductility.

[0026] The elastic material used to provide the layers can be a material with a Shore A hardness between 30 and 80. However, the 3D structure can have a lower Shore A hardness compared to the elastic material because the material can be made of many walls of layered material that can be separated from each other. Therefore, the hardness of the structure can be a combination of the hardness of the wall structure and the hardness of the spacers between the walls. Furthermore, due to the yieldability of the walls, the walls may deflect or bend at a rate lower than the hardness of the elastic material. Therefore, the individual layers can be stable in the direction of compressive force, where each layer is minimally compressed on its own basis under the force it experiences.

[0027] Viewed from the direction of the first axis, the order of the structural layer, the first flexible layer, and the second flexible layer can be: the first-level structural layer, followed by the first flexible layer and the second flexible layer. Alternatively, the order can be: the first flexible layer, followed by the first-level structural layer, followed by the second flexible layer. Or, the order can be: the first flexible layer, followed by the second flexible layer, followed by the first-level structural layer.

[0028] This means that when a force is applied in a direction parallel to the longitudinal axis, the first and / or second flexible layers will deviate from the longitudinal axis before the first structural layer deviates from the longitudinal axis.

[0029] When a compressive force is applied to a wall in its longitudinal direction, a wall with a layered structure having identical layers along its entire length can have a degree of predictable collapse force. However, it is almost impossible to predict how the wall will collapse because when the force is not perfectly parallel to the longitudinal axis, collapse can occur in the direction of the force, which has a significant impact on how the wall may collapse or bend. Furthermore, another problem is that when the wall collapses, it may lose most or all of its reaction force to the compressive force, meaning that once the wall collapses, it loses most of its reaction force because the wall may completely fold and / or collapse.

[0030] However, by employing a structure in which structural and flexible layers are applied repeatedly along the longitudinal axis, for example, it is possible to predict where the first wall will yield to compressive forces. This is because the flexible layers may have reduced stiffness and / or resistance to forces, ensuring that the wall will always deviate in the areas with flexible layers before it deviates in the areas with structural layers. Therefore, it is possible to make the wall collapse / deviate in a predictable manner under compressive forces, making it easier to construct the wall to collapse under a given force. Furthermore, this allows the wall to collapse or deviate in a controlled manner, so that even if the flexible portions have deviated or collapsed between the structural portions, the structural portions of the wall can maintain a reaction force against compressive forces.

[0031] The first wall can be part of a larger structure, where each layer of the wall can correspond to a layer of the larger 3D structure, and where the larger 3D structure can have multiple layers. The first wall can be part of a structure having a second wall, a third wall, or subsequent walls. The first wall can be part of a structure, where the first wall is part of a honeycomb structure, where the first wall is part of a closed lattice (viewed from above) such as a circle, ring, triangle, hexagon, or any suitable polygonal closed lattice, where the first wall and / or multiple walls define the volume of the lattice.

[0032] In one or more embodiments, the first-level structural layer and / or the first and / or second flexible layer may be attached to another layer via a boundary, wherein the boundary between the two layers may have a stiffness less than that of the first-level structural layer and / or the flexible layer. This means that when the first wall deviates from the first axis, the deviation of the two layers will pivot across the boundary (observable in a cross-sectional view). This means that the layers can deviate in a predetermined area, which means that the deviation of the first wall can be predicted and / or anticipated, which can be further controlled by adjusting the stiffness of the layers or the stiffness of the boundary between the layers.

[0033] In one or more embodiments, the structural layer may have a first surface and a second surface. When the first wall is in an uncompressed state, the first surface and / or the second surface of the structural layer may be considered as the portion of the layer intersecting the first axis. The first surface and / or the second surface of the structural wall may be considered as the portion of the layer facing the preceding or following layer of the first wall. Therefore, the first surface and / or the second surface may have a tangent axis substantially orthogonal to the first axis (observed in a cross-sectional view). The first surface and / or the second surface may be considered as the portion of a layer adjacent to another layer of the wall.

[0034] When a wall is constructed linearly, the uncompressed state of the first wall can be a case where the first axis intersects all and / or at least a plurality of layers of the first wall, wherein each layer of the wall is stacked on top of each other along the first axis. An intermediate state of the first wall can be, for example, a case where the first axis intersects all and / or at least a plurality of layers of the first wall, wherein the compressive force may be, for example, too low to force one or more layers of the wall to deviate from the first axis. The compressed state of the first wall can be a case where at least one layer of the first wall deviates from the first axis.

[0035] In one exemplary embodiment, a first-level structural layer may be adjacent to a first flexible layer and a second flexible layer along a first axis. This means that the first-level structural layer of the first wall may have a first flexible layer on a first side of the first-level structural layer and a second flexible layer on an opposite second side of the first-level structural layer. Therefore, the first axis may intersect the flexible layer, the structural layer, and the flexible layer in this order along its length. This allows the first-level structural layer to be surrounded by flexible layers, i.e., at the top and bottom, thereby allowing the flexible layers to deform before the structural layers deform when a force is applied to the first wall.

[0036] The structural layer can be any kind of structure that constitutes a wall with increased stiffness compared to the flexible layer. The structural layer may comprise multiple layers in the direction of the first axis, wherein these layers may be stacked on top of each other to form a portion of the wall with increased stiffness. The structural layer may have a height similar to or the same as the height of the first layer in the direction of the first axis. However, the structural layer may alternatively have a height greater than the height of the flexible layer.

[0037] Therefore, the walls and structural layers can be used as mechanical devices that can store energy and then release it to dampen or maintain the force between the contact surfaces (the first and second ends of the wall).

[0038] In one or more embodiments, the first layer may be adjacent to the second layer in the direction of the first axis. This means that the first layer may be located on top of the second layer, or it may be located below the second layer. By positioning the layers on top of each other, the first and second layers provide part of a 3D-printed construct, which can be constructed as a multi-layered structure that can be positioned on top of each other. Thus, the wall portions of the 3D construct can constitute a 3D-printed structure, wherein one layer of the wall structure may have a different stiffness than another layer of the same wall structure, and / or wherein one layer of the wall portion may have a different stiffness than layers of different wall portions within the same layer.

[0039] In one or more embodiments, the second wall portion of the second layer may include a second-level structural layer or a third flexible layer. By providing a second-level structural layer or a third flexible layer to the second wall portion, the 3D-printed structure of the first wall portion can have the same number of layers as the second wall portion, and can have similar or lower stiffness than the first wall portion, respectively. That is, when both the first and second wall portions have the same number of layers, and when both wall portions have structural and flexible layers, their combined stiffness is substantially similar. However, when the first and second wall portions do not have the same amount of flexible and structural layers, the wall portion with fewer structural layers has lower stiffness than the wall portion with more structural layers. Therefore, the stiffness of the wall portion can be controlled by adjusting the number of structural and flexible layers.

[0040] In one or more embodiments, the first flexible layer may be adjacent to a second or third flexible layer. This means that the second or third flexible layer may provide a specific structure for the second wall portion, wherein the second flexible layer may increase the combined stiffness of the second wall portion by being adjacent to the second flexible layer, or the third flexible layer may ensure that the stiffness of the second wall portion is lower than that of the corresponding layer of the first wall portion.

[0041] In one or more embodiments, the 3D-printed structure may include a third wall. The third wall can provide increased variability to the 3D-printed structure, wherein the third wall may be constructed from layers similar to the first and / or second walls, but wherein the third portion may have a different layered structure in the respective layers in the direction of the first axis than the first and / or second walls. Alternatively, if the construction of the 3D-printed structure requires a third wall, the third wall may have a structure similar to the first and / or second walls.

[0042] In one or more embodiments, the first layer may further include a third wall portion, wherein the third wall portion includes a second flexible layer or a second secondary structural layer in the first layer. The third wall portion may provide another layer for the 3D printed structure, wherein the third wall portion may have similar stiffness to the first wall portion and / or the second wall portion in the same layer, or may have different stiffness, i.e., higher or lower than the stiffness of the first wall portion and / or the second wall portion.

[0043] In one or more embodiments, the second layer includes a third wall portion, wherein the third wall portion includes a flexible layer or a structural layer within the second layer. The third wall portion may have the same number of layers as the first wall portion and / or the second wall portion, such that the first, second, and third wall portions have the same height.

[0044] In one or more embodiments, a first wall may be adjacent to a second wall and / or a third wall may be adjacent to a second wall in a direction along a second axis. This means that these walls may extend in a specific direction. The second axis may also be a circular section, wherein the first, second, and third walls may be connected in a ring-shaped or polygonal manner to create a closed structure, such as a portion of a lattice. Thus, the first, second, and / or third walls may be adjacent to each other in a ring-shaped or partially ring-shaped manner, wherein these walls form a portion of a ring-shaped structure.

[0045] In one or more embodiments, the second flexible layer may be adjacent to the first structural layer. The second flexible layer may be adjacent to the first structural layer in a direction along a second axis, wherein, when viewed along the second axis, the second flexible layer is located on the side of the first structural layer.

[0046] In one or more embodiments, the flexible layer may have a primary surface and a secondary surface. When the first wall is in an uncompressed state, the primary surface and / or secondary surface of the flexible layer can be considered as the portion of the layer intersecting the first axis. The primary surface and / or secondary surface of the flexible wall can be considered as the portion of the layer facing the preceding or following layer of the first wall. Therefore, the primary surface and / or secondary surface may have a tangential axis substantially orthogonal to the first axis (observed in a cross-sectional view). The first surface and / or second surface can be considered as the portion of the layer adjacent to another layer of the wall.

[0047] When a wall structure has already been formed, the layers of the first wall can be fused, bonded, mixed, integrated, and / or merged, where the boundary between two layers of the wall may be indistinguishable. However, during the 3D printing of the first wall or any subsequent wall, the wall is formed layer by layer, with one layer positioned on top of the previous layer (the layer that has already been formed and positioned), where the first surface of the previous layer is adjacent to the second surface of the subsequent layer (the layer on top of the previous layer). The positioning of these two layers can be done before curing, such that the first and second surfaces intersect and may be indistinguishable from each other. Alternatively, the first surface can be permanently bonded or adhered to the second surface, where the boundary between the two layers can be observed in a microscopic view of the cross-section of the first wall or any subsequent wall.

[0048] In one or more embodiments, stiffness may be in the longitudinal direction. The longitudinal direction may be a direction parallel to a first axis of the first wall. The stiffness of the layer of the first wall or any subsequent wall can be considered as stiffness representing the flexibility of the layer in the longitudinal direction. That is, where stiffness indicates how the layer tends to move in the longitudinal direction. High stiffness will mean that the layer may require increased forces to arrange the layer in the longitudinal direction compared to a layer with lower stiffness, and vice versa.

[0049] In one or more embodiments, stiffness may be in the lateral direction. The lateral direction may be a direction transverse to the first axis of the first wall. The stiffness of the layer of the first wall or any subsequent wall can be considered as stiffness representing the flexibility of the layer in the lateral direction. That is, where stiffness indicates how the layer tends to move in the lateral direction. Higher stiffness would mean that the layer may require increased forces to arrange the layer in the lateral direction compared to a layer with lower stiffness, and vice versa.

[0050] In one or more embodiments, stiffness can be in the direction of rotation. The direction of rotation can be the direction of rotation along the longitudinal axis of the layer of the first wall, wherein the longitudinal axis of the layer of the first wall can be substantially orthogonal (right-angled) to the first axis of the first wall. Therefore, the stiffness of the layer of the first wall or any subsequent wall can be considered as stiffness representing the flexibility of the layer in the direction of rotation. Thus, when a compressive force is applied to the wall of the structure, one or more layers may deviate from the first axis of the wall, wherein one layer may be bonded to another layer, meaning that the compressive force will create a torque applied to that layer or both layers. The stiffness of the layer can be, for example, in the direction of rotation that can represent the connection between two layers, i.e., the rotational flexibility of a single layer. Flexibility in the direction of rotation can be considered as resistance to torsional movement of the layer in response to the applied force, i.e., how the layer responds to the applied force to resist rotational movement. Rotational stiffness and / or hardness can also be considered as torsional stiffness, hardness, and / or flexibility.

[0051] In one or more embodiments, the structural layer may have a width (transverse to the longitudinal axis) greater than the thickness of the flexible layer.

[0052] The structural layer has a width (transverse to the longitudinal axis) greater than 110%, 120%, 130%, or 150% of the thickness of the flexible layer. The structural layer may have a width approximately twice that of the flexible layer.

[0053] Structural layers can be formed as two or more layers of flexible material adjacent to each other in the transverse direction. This means that these two layers can be located within a single layer of the wall structure, and each layer is bonded to the preceding and / or following layer of the structure, as well as to the adjacent layer in the transverse direction. Therefore, a first-level structural layer or any subsequent layer can consist of two or more layers of material, each comparable to a flexible layer of the wall structure. Providing two or more layers of material to form structural layers will increase the stiffness of the wall layers because the material may have increased width when the two or more layers are bonded to each other and to adjacent layers in the longitudinal direction. Two adjacent layers can have a height comparable to or the same as the height of the flexible layer (in the longitudinal direction), where the introduction of the adjacent layer does not change the height of the structural layer. Therefore, structural layers can have a similar or the same height as the flexible layer.

[0054] In one or more embodiments, the first wall may have at least a second-level structural layer and / or at least a third flexible layer. Continuing the first-level structural layer and / or flexible layer, a second-level structural layer may be further provided to the wall of the 3D-printed structure, wherein additional structural layers may be provided to increase the height of the wall and / or increase the stiffness of the wall. Continuing the first-level structural layer, the second-level structural layer, the first flexible layer, and / or the second flexible layer, a third flexible layer may be further provided to the wall of the 3D-printed structure, wherein another flexible layer may be provided to increase the height of the wall and / or decrease the stiffness of the wall. The first wall or any subsequent wall may be provided with multiple structural and / or flexible layers to provide a wall of a predetermined length along a first axis.

[0055] In one or more embodiments, the order of the structural layers and flexible layers can be repeated along a first axis. This means that the structure and the order of the first and second flexible layers can be reproduced along the length of the wall (along the first axis), wherein the first-level structural layer and the second-level structural layer can be separated by one or more flexible layers; in one example, the two structural layers are separated by two flexible layers. Therefore, the length of the wall can have a structure in which the structural layer can be adjacent to one or two flexible layers on each side (above and below the longitudinal length), wherein this order can be repeated along the length of the wall.

[0056] In one or more embodiments, the first wall may have a repeating layered structure along the longitudinal axis of at least one primary structural layer and at least one flexible layer.

[0057] This means that the flexible layer can be configured to have a different compressive force than that applied to the first wall in the region between the two structural layers, so that the wall can decrease in height from its first end to its second end.

[0058] In one or more embodiments, the first and second level structural layers may be separated by at least a first flexible layer. By employing at least one flexible layer to separate the first and second level structural layers, the deformation of the first wall along its longitudinal axis can be controlled, wherein the flexible layer, having a lower stiffness than the structural layer, will deform before the structural layer deforms. Therefore, how the first wall will deform can be predicted more accurately, and thus the stiffness of the structural layer and / or any wall surrounding the first wall can be adjusted to provide a first wall with predictable and controllable overall wall stiffness in itself.

[0059] In one or more embodiments, the height of the structural layer may be substantially similar to the height of the flexible layer. By providing the structural layer at a similar height to the flexible layer, wherein, in one or more embodiments, the height of the structural layer is the same as that of the flexible layer, the structural layer can be exchanged with the flexible layer during the construction of the wall, and vice versa, without having to recalibrate the total height of the wall due to the exchange of a structural layer with a flexible layer, and vice versa. Therefore, the length (height or total height) of the wall to be manufactured / printed in the first axial direction can be defined by the total number of layers, wherein the specific number of particular layers does not affect the length of the wall, and particular types of layers can be interchanged without special modification and calculation of the total length of the wall. This also means that the introduction of structural walls can be selectively done at any location in the layers of the article to be 3D printed without affecting subsequent layers of the article, and without compensating for the structural layer in the subsequent layers of the wall.

[0060] In one or more embodiments, the first-level structural layer may be separated by two or more flexible layers in the longitudinal direction. Separating the first-level structural layer from two or more flexible layers means that, in the longitudinal direction (direction of the first axis), the first-level structural layer is followed by at least two flexible layers. This means that the at least two flexible layers provide a region (in the longitudinal direction) for the wall that can be considered more flexible (less stiff), thereby allowing the wall to collapse more easily in this region. Therefore, providing two flexible layers adjacent to each other in the first axial direction may also mean that the flexibility of the bond between the two layers is less than that between the structural layer and the flexible layer, which may mean that when a compressive force is applied to the wall in the first axial direction, one flexible layer can more easily deviate from the other.

[0061] In one or more embodiments, the first flexible layer may be adjacent to the first primary structural layer. By having the first primary structural layer adjacent to the first flexible layer in the direction of the first axis, the flexibility of the wall in the direction of the first axis can be increased. The flexible layer will have a lower stiffness than the structural layer, such that the total stiffness of the combined two layers will be less than, for example, two structural layers adjacent to each other. Therefore, the flexibility of the wall can be increased by providing a flexible wall without changing the composition of the material used for 3D printing.

[0062] In one or more exemplary embodiments, the first wall, second wall, third wall, or any subsequent wall may have a first height and a first end and a second end, wherein the first-level structural layer is positioned at a distance of at least 20% of a first length from the first end and / or at least 20% of a distance from the second end. The first height may be the distance from the first end to the second end along a first axis. Thus, in an example where the first wall has a height of 10 mm, the first-level structural layer may be located in a region between 2 mm and 8 mm of the height of the first wall. This means that the wall may have a structural layer located in the central region of the wall. Therefore, the central region of the first wall may have both a first flexible layer and a second flexible layer, as well as the structural layer. Thus, when a force is applied to the wall, the deformation of the first wall can be controlled. In a second example, the central region of the first wall may have two or more structural layers, wherein each structural layer may be separated by one or more flexible layers.

[0063] In one or more embodiments, the first axis may intersect the central axis of the structural layer and / or the flexible layer. This means that the first wall can be provided in a manner that allows the structural and flexible layers to be provided linearly, wherein each layer is stacked directly on top of each other, thereby transmitting any compressive forces applied to the first wall in a direction parallel to the first axis through all layers of the wall having a central axis that intersects the first axis. The central axis of a layer can be considered as a longitudinal axis following the length of the layer and can be considered as perpendicular to the cross-section of the layer.

[0064] In one or more embodiments, the elastic material may be a silicone material or a mixture of silicone materials. 3D printing can be accomplished by adding one layer on top of another and then continuing this process until the wall has the desired height. Liquid form polymers can advantageously be used for 3D printing, which solidify when they are in their correct position. Thus, when solidified, the 3D-printed structure can be made of a polymeric material. One example is a liquid silicone polymer, which is added on top of the layer in the same direction as the layer, so that the wall can be a plurality of discrete lines of polymer added on top of each other, wherein these lines are parallel to each other when 3D printed on top of each other. The material is advantageously elastic, such that the deformation of the material during the application of pressure is reversible, and the material does not plastically deform when elastic deformation occurs. That is, it has a high stress / strain ratio before plastic deformation occurs.

[0065] In one embodiment, the hardness of the polymer upon curing can be between 20 and 90 Shore A, preferably between 30 and 85 Shore A, more preferably between 35 and 80 Shore A, and even more preferably between approximately 40 and 60 Shore A. An example of a polymer is a silicone resin, one type of which could be Dow Corning LC3335 Liquid Silicone Rubber designed for 3D printing, having a Shore A hardness of approximately 50. Other types of polymers and silicone resins suitable for 3D printing may also be used, and a particular type of silicone resin or polymer is not critical to the invention, but the elasticity, hardness, and functionality of the 3D printed material may be considered important factors.

[0066] The 3D printing method uses fusion deposition modeling, which forces two confined fluids through a static mixer and then, depending on the precise application, extrudes them from a nozzle. One type of printing equipment that can be used is the German RapRap GMbH X400 PRO 3D printer. Other types of printers can also be used.

[0067] In one embodiment, the thickness of each layer can be between 0.1 and 1.6 mm, more preferably between 0.2 and 1.2 mm, even more preferably between 0.3 and 1.0 mm, or even more preferably between 0.4 and 0.9 mm. The layer thickness can be controlled by the thickness of the 3D printing lines and / or the multiplicity of the 3D printing lines. Because increased thickness will provide increased resistance and / or increased stiffness, the line thickness can control the wall's resistance.

[0068] In one or more embodiments, the structural layers may be made of a first material component and / or the flexible layers may be made of a second material component, wherein the first material component is different from the second material component. Therefore, the 3D printed structure may be made of at least two different material components, wherein the material components can affect the behavior and compressibility of the layers when compressive forces are applied.

[0069] The morphology of a 3D printed structure can be adjusted by providing walls in different numbers of layers, wherein parts of the 3D printed structure intended to have a reduced height can be provided with fewer layers of walls, while parts of the 3D printed structure intended to have an increased height can be provided with an increased number of layers on top of each other.

[0070] In an example where the 3D-printed structure can be a shoe midsole, the area intended to have a lower height could be, for example, the forefoot area, while the higher areas could be, for example, the arch area of ​​the medial portion of the 3D-printed structure, and, for example, the heel area. Therefore, since the 3D-printed structure can be formed entirely according to the shape of a particular user's foot, the shoe in which the midsole is used can be formed in a relatively universal form, where the upper and outsole can be joined together, and where the inner surface of the outsole can be relatively flat and not shaped like the foot in terms of height. Thus, the inner surface of the outsole, i.e., the foot-facing surface of the outsole, or the foot-facing surface of the shoe, if provided with a middle portion, can be relatively flat and can be configured as a receiving surface for the lower part of the 3D-printed midsole. Therefore, the foot-facing surface of the outsole can be provided in the shape of the foot in the longitudinal and transverse directions, but in the height direction, i.e., in the direction perpendicular to the longitudinal and / or transverse directions of the foot, it does not have any characteristic foot shape. Therefore, shoes that are the correct size (along the longitudinal axis of the shoe) for the user can be provided with a 3D-printed midsole that is specifically shaped to conform to the user's foot profile on the foot-facing surface, especially in the height direction, and can be reinforced or softened in areas specifically selected for each particular user during walking, running, or stationary positioning based on gait, forces transmitted from the foot, and the shape of the foot profile.

[0071] Therefore, this application may also relate to a shoe with a 3D-printed midsole, which is made from a 3D-printed structure according to the above disclosure.

[0072] Another way to control the resistance of a 3D printed structure is how one wall is attached to a second wall and the shape of that wall. If one wall is attached to another wall at an angle, that is, the planes of the walls intersect at an angle, the second wall can provide increased resistance to the first wall, and vice versa. This is because the walls are angled relative to each other and provide structural resistance to each other, especially if one wall is attached to the second wall along its entire height.

[0073] The 3D printed structure may be provided with multiple walls, wherein the multiple walls define multiple lattices, the lattices having a central axis substantially parallel to the walls and having a radius from the walls to the central axis.

[0074] When pressure is applied to the wall and the force applied to the wall exceeds a certain limit, the wall will deform. Since the bottom end of the wall (the second end) is confined inside the shoe by the foot-facing surface of the outsole, the first end will move in the direction towards the second end. As this occurs, the wall will deform by buckling, spreading, or other means to allow the first end to move in a downward direction. Because the wall will deform, it is advantageous that the deformation of the wall is unrestricted in at least one direction, i.e., towards the central axis of the perforation. Therefore, the deformed wall is allowed to deform freely into the perforation, thereby reducing the radius between the wall and the perforation in at least one region. The shape of the perforation, such as its shape when viewed from above or the side, also affects the deformation of the wall, because the connecting walls and the angles of connection may increase or decrease the wall's resistance.

[0075] A single lattice can be provided by a circular wall, which provides cylindrical walls in multiple layers, wherein the outer surface of the circular wall can be connected to a second wall. Therefore, the lattice structure can be multiple cylindrical lattices connected to other cylindrical lattices via walls. The circular wall can include a first wall, a second wall, and / or a third wall, wherein the first wall, the second wall, and / or the third wall can be regions of the circular wall at different locations along the circular wall. Thus, the first wall can be positioned, for example, at an angle of 0-60 degrees, while the second wall can be positioned at an angle of 61-120 degrees, and the third wall can be positioned at an angle of 121-180 degrees. Alternatively, the first wall can be positioned, for example, at an angle of 0-120 degrees, while the second wall can be positioned at an angle of 121-240 degrees, and the third wall can be positioned at an angle of 240-360 degrees. The circular wall can have a 360-degree rotation, wherein the rotation is about a central axis of the circular wall, wherein the central axis extends through the center of the circular wall.

[0076] In one embodiment, a 3D-printed structure of elastic material having at least a first layer and a second layer can be provided. The 3D-printed structure includes: at least a first wall comprising at least a first primary structural layer and at least a first flexible layer; and at least a second wall comprising at least a second primary structural layer and at least a second flexible layer. The 3D-printed structure includes a third axis intersecting the first and second layers, and intersecting both the first and second primary structural layers. The first primary structural layer has a first stiffness, and the first flexible layer has a second stiffness, wherein the first stiffness is greater than the second stiffness.

[0077] The aforementioned 3D printed structure, wherein the third axis intersects two layers of the 3D printed structure and the first and second level structures, means that the third axis is provided at an angle to the first and second layers, which are substantially parallel to each other. This may also mean that the angled third axis can extend through the first layer, into the second layer, and continue to subsequent layers of the second layer. Furthermore, structural layers exist within different walls of the 3D printed structure, where the first and second walls may have substantially parallel first axes. This also means that the third axis is at an angle to the walls of the 3D printed structure. That is, the third axis can be considered to have an angle between the first axis parallel to the first wall and the second axis parallel to the first layer. Specifically, if the first axis has an angle of 90 degrees and the second axis has an angle of 0 degrees, then the angle of the third axis can be greater than 0 degrees but less than 90 degrees, thereby allowing the third axis to intersect at least two layers of the 3D printed structure and at least two walls of the 3D printed structure.

[0078] The intersection of the third axis in each layer implies that the first and second layers are different from each other, and that the first and second structural layers are separated from each other; that is, the axis may not intersect with the structural layers of the first and second structures and / or the individual walls at the same location. Therefore, the layers and structural layers of the 3D structure may intersect the third axis at different locations; that is, the intersections in the layers of the 3D structure are at different locations along the third axis, and the same applies to the structural layers of the walls.

[0079] By positioning each structural layer along the third axis, interactions can be achieved between structural layers and / or flexible layers in different layers of the 3D printed structure. The increased stiffness of the structural layers compared to the flexible layers can generate an elastic / spring effect between two layers in different walls, thereby allowing the different walls of the 3D printed structure to have elastic mechanical interactions between the walls. Thus, the stiffness of the 3D printed structure provided by the structural layers can follow the entire 3D printed structure along the third axis.

[0080] In one or more embodiments, the 3D-printed structure may include a third layer and optionally at least a third wall, the third wall comprising at least a third-level structural layer and at least a third flexible layer, wherein a third axis intersects the third layer and the third-level structural layer. Thus, the 3D-printed structure may be provided with another wall having a third-level structural layer and at least a third layer of the 3D-printed structure, wherein the third axis intersects both the third layer and the third structural layer. Therefore, the third wall can provide another connection to the first and second walls to provide an elastic relationship between the first and second walls and the third wall. Because the third axis intersects the third-level structural layer, the increased stiffness of the three structural layers, compared to the flexible layer that may surround the structural layers in the wall, can follow the third axis through multiple layers and multiple walls of the 3D-printed structure.

[0081] In one or more embodiments, the first wall, second wall, and / or third wall may each include a first-level first axis, a second-level first axis, and a third-level first axis. Each of the first, second, and / or third walls may include a first axis, wherein the structure of the flexible layers and structural layers in the wall may follow the first axis. The structure may be different from one wall to another, or it may be similar for each wall, for example, the positioning may shift from one wall to another. That is, the structural layer is a first layer in the first wall, a second layer in the second wall, and a third layer in the third wall, and so on.

[0082] In one or more embodiments, the first-level structural layer and the second-level structural layer may be located in different layers of the 3D printed structure. By providing the first-level structural layer and the second-level structural layer in different layers of the 3D printed structure, the stiffness of the wall can be shifted from one wall to another in a diagonal manner, that is, the increased stiffness of the second wall is provided in layers of structural layers below or above the first wall.

[0083] In one or more embodiments, the third-level structural layer may be located in a layer of the 3D printed structure that is different from the first and / or second-level structural layers in the 3D printed structure. Therefore, the third-level structural layer can be in a layer different from the first and second-level structural layers. That is, if the first-level layer is in the first layer and the second-level layer is in the second layer, then the third-level structural layer can be in a layer different from the first and / or second layers. Thus, the structural layer can thereby be displaced vertically from one wall to another, allowing the stiffness of the structural layer to be transmitted along a third axis.

[0084] In one or more embodiments, a first wall may be adjacent to a second wall, and / or a third wall may be adjacent to a second wall. By making the first and second walls adjacent to each other, and optionally the third wall adjacent to the second wall, stiffness can be directly transferred from one wall to another. Therefore, the stiffness of a structural layer in one wall can be directly transferred to another wall, where the stiffness of a wall will be influenced by the structural layers in adjacent walls. Furthermore, by making the walls adjacent to each other and having a third axis intersecting each structural layer, stiffness can be transferred from one wall to another, producing a cooperative effect of transfer between the various walls of the 3D printed structure.

[0085] In one or more embodiments, the first and second walls, and optionally the third wall, may form part of a closed aperture grid defining a predetermined volume of the aperture grid. Thus, the closed aperture grid viewed from above may have a view in which the walls define the aperture grid boundaries, and may be part of a plurality of walls that generate the closed aperture grid. The closed aperture grid may, for example, have six walls connected in a ring-like manner, such as in a hexagonal shape, where the first wall is adjacent to the second wall, and the third wall is adjacent to the second wall, and the fourth wall is adjacent to the third wall, and so on. On the opposite side of the first wall, the closure of the aperture grid may, for example, have a sixth wall adjacent to the first wall. By having structural layers in each wall, and each layer intersecting a third axis, the structural layers may be displaced in an upward or downward direction when a wall is compared to its adjacent wall. Therefore, the stiffness of the walls of the closed aperture grid can vary from one wall to another. The closed aperture grid may have any suitable shape.

[0086] In one or more embodiments, the third axis may be a helical axis and / or a spiral axis. By providing a third axis in the form of a helical axis and / or a spiral axis, this axis may follow a coiling path, which may, for example, follow the walls (i.e., the outer walls) of a closed aperture. By providing the third axis in, for example, a spiral path, and wherein the third axis intersects with structural layers in the wall, the structural layers of the wall may also follow a helical path. Thus, this means that the stiffness of the wall can be formed in a helical manner, such that the closed aperture may, for example, have a stiffness profile that mimics a coiled spring along the periphery of the closed aperture. Thus, this means that the walls of the closed aperture can function in a manner similar to a coiled spring, wherein forces applied along the direction of the first axis are transmitted from one wall to other walls via structural layers, wherein when following a path of the helical axis, forces are transmitted in both the lateral direction (second axis) and in the upward and / or downward directions. Thus, these walls and structural layers can be used as mechanical devices that can store and subsequently release energy to dampen or maintain forces between contact surfaces.

[0087] In one or more embodiments, the first-level structural layer is part of a first layer, and the second-level structural layer may be part of a second layer. Optionally, the third-level structural layer may be part of a third layer. This provides a wall structure in which the structural layers of the wall are offset by one layer compared to the previous wall. This can also mean that when a structural layer is located within a layer, the structural layer is integral part of that layer, or a layer in a certain location may contain or consist of a corresponding structural layer.

[0088] In one or more embodiments, the intersection point of the third axis in the first-level structural layer may be located at the same position as the intersection point in the first layer, and the intersection point of the third axis in the second-level structural layer may be located at the same position as the intersection point in the second layer. Optionally, the intersection point of the third axis in the third-level structural layer may be located at the same position as the intersection point in the third layer. Therefore, the third axis will intersect the structural layer and the layer at the same position, such that the intersection point of one layer and one structural layer can be seen at at least one point in three-dimensional space. Attached Figure Description

[0089] The following is a description of an exemplary embodiment with reference to the accompanying drawings, wherein...

[0090] Figure 1a and 1b Cross-sectional views of the first and second embodiments of the 3D printed wall according to this description are shown.

[0091] Figure 2a , 2b Figure 2c shows a 3D-printed wall and a cross-sectional view of how the wall can react when compressive force is applied.

[0092] Figure 3 A stereoscopic view of an example of a 3D-printed wall is shown.

[0093] Figure 4 A cross-sectional view of another embodiment of the 3D printed wall is shown.

[0094] Figure 5 Micrographs of three cross-sections of the 3D-printed wall are shown.

[0095] Figure 6a , 6b Figures 6 and 6c show three separate layers of the 3D printed structure.

[0096] Figure 7a and 7b A three-dimensional diagram of the layered structure at different steps is shown, and

[0097] Figure 8 A cross-sectional view of a portion of the 3D printed structure is shown. Detailed Implementation

[0098] Figure 1 illustrates a first exemplary embodiment of a 3D-printed structure 1 as observed in a schematic cross-sectional view, having a first wall 2 having multiple layers extending along a first axis A. The first wall 2 includes a first-level structural layer 3, a first flexible layer 4, and a second flexible layer 5. In this exemplary embodiment, the first wall 2 includes a second-level structural layer 6, a third-level structural layer 7, and a quaternary structural layer 8, wherein each of the second-level structural layer 6 and the third-level structural layer 7, and each of the third-level structural layer 7 and the quaternary structural layer 8, is separated by two flexible layers 9, 10, 11, and 12, respectively. That is, the structures of the first-level structural layer 3 and the first flexible layer 3 and the second flexible layer 4 are repeated along the length of the wall 2 in the longitudinal direction A of the wall 2.

[0099] The first structural wall 3, the first flexible wall 4, the second flexible wall 5, and subsequent walls are 3D printed using an extruded line of flexible material with height H and width W. In the 3D printed structure, a material layer can be of height H and can be applied in a continuous manner according to the requirements of the 3D printed structure.

[0100] In this embodiment, the structural layer 6 in wall 2 is provided as two separated lines 12, 13 of extruded flexible material, wherein the two separated lines 13, 13' are joined to each other at a joint sidewall, wherein the joint sidewall 14 provides a permanent bond between the two lines 13, 13' of the material. Furthermore, the structural layer 6 may be joined to at least one flexible wall 5, 9, wherein the upper wall 15 or lower wall 16 of the flexible wall may be joined to the upper or lower wall of the structural layer 6, thereby creating a permanent bond between the two layers. The bond between the layers may extend along the entire length of layers 6, 5, 9 along axis B, substantially perpendicular to the 2D plane shown in this cross-sectional view. Flexible layers 9, 10 may also be joined along the entire length of layers 9, 10. As seen in this embodiment, the structural layer 6 has a width approximately twice the width (2W) of the flexible layers 5, 9 (W). The width of structural layer 6 ensures that it has higher stiffness than flexible layers 5 and 9, so that when a compressive force is applied to wall 2 in the direction of the first axis A, structural layer 6 will resist deformation for a longer time than the flexible layers. Figure 1a All structural and flexible layers shown are considered in the same way.

[0101] Similarly, Figure 1b Another exemplary embodiment of the wall 20 is shown, wherein the wall includes a first-level structural layer 21, a second-level structural layer 22, and six flexible layers 23, 24, 25, 26, 27, 28 in the direction of the first axis A, the flexible layers 23, 24, 25, 26, 27, 28 separating the first-level structural layer 21 from the second-level structural layer 22. Two or more flexible layers are provided below the second-level structural layer 22. In this embodiment, given that... Figure 1aThe illustrated embodiment increases the number of flexible layers. It is assumed that the two walls are manufactured in a similar manner, with similar materials and similar dimensions to a flexible material with similar height (H) and width (W). This means that the overall stiffness of wall 20 is less than... Figure 1a The wall 2 shown in the diagram. The increase in flexibility is due to the wall having a higher flexibility per unit length along axis A than... Figure 1a The fact that wall 2 has more flexible layers means that when a compressive force is applied in the direction of axis A, structural layers 21 and 22 will resist deformation, while any one of the flexible layers 23, 24, 25, 26, and 27 can deform before structural layers 21 and 22.

[0102] Figure 2a A wall 30 with three structural layers 31, 32, and 33 is shown, the structural layers 31, 32, and 33 being separated from each other by a first group of three flexible layers 34, 35, and 36 and a second group of flexible layers 37, 38, and 39. When the wall 30 is in its uncompressed state, the first axis A intersects the central portion of each layer, allowing the wall 30 to have a substantially upright shape.

[0103] An increase in compressive force along axis A will cause deformation of the flexible materials in layers 34, 35, 36, 37, 38, and 39, resulting in a change in the shape of wall 30 due to the material's flexibility. As the compressive force increases, wall 30 will eventually deform in a manner that causes it to bend away from the first axis A. Assuming the first end 40 and the second end 41 of the wall are in fixed positions, deformation of the wall will most likely occur in the central portion 42 of wall 30, where the central portion 42 will deviate from the first axis A. Since the wall is composed of layers with different stiffnesses, the portions of the wall with lower stiffness, such as flexible layers 34, 35, 36, 37, 38, and 39, are likely to become the first areas to deform, thus causing the wall to deviate from axis A in the regions of flexible layers 34, 35, 36, 37, 38, and 39, where structural layers 31, 32, and 33 will resist deformation until a certain point. An example of deformation can be seen in… Figure 2b In the middle, two flexible layers 35 and 38 have deviated in the lateral direction C, and both layers have deviated in the same direction c1. This causes the length of the wall to decrease from its initial length X to its compressed length Y, as shown in the figure. Figure 2b As shown.

[0104] exist Figure 2cThe same situation is illustrated in the diagram, where a compressive force is applied to the wall 30, and the flexible layer 35 deviates in direction c1 and in direction c2. Directions c1 and c2 are shown only as examples, and the flexible layers can deviate in the same direction, opposite directions, or alternating directions. A similar deviation can occur when there are only two flexible layers, where the flexible layers can deviate in the direction shown by axis C in a direction away from the first axis A.

[0105] Figure 3 Another embodiment of the 3D-printed structure 1, as shown in the schematic diagram, is illustrated with a schematic cross-sectional view. It has a wall 50, which includes at least a first-level structural layer 51, a first flexible layer 52, and a second flexible layer 53. The wall also includes a second-level structural layer 54 and four additional flexible layers 55, 56, 57, and 58. Each layer of the wall 50 has a longitudinal axis D that extends along the length of each layer and along its center.

[0106] form Figure 3 The 3D printed structure shown is such that the longitudinal axis D of layers 51-58 is substantially centered along the length of wall 50 in the direction of axis A, that is, axis D intersects the longitudinal axis D of each layer. This means that when a compressive force is applied to wall 50 in the direction of axis A, the force is transmitted to the center of each layer and can be similar to... Figure 2b and 2c As shown, the auxiliary wall 50 maintains its height (e.g., before the flexible layer begins to deform and move away from the longitudinal axis A) Figure 2a As shown in X), until the predetermined compressive force is reached.

[0107] Figure 4 A schematic cross-sectional view of wall 60 is shown, similar to... Figures 2a-2c As shown, it has three structural layers 61, 62, 63 and six flexible layers 64, 65, 66, 67, 68, 69. In this exemplary embodiment, the longitudinal axes D of the flexible layers 65 and 68 have been offset from the longitudinal axis of the wall 60 in directions c1 and c2. This offset of the longitudinal axes ensures that when a compressive force is applied in the direction of the longitudinal axis A of the wall 60, the flexible layers 65 and 68 are pre-arranged or biased to deviate in directions c1 and c2, thereby allowing the wall 60 to bend in these directions. The offset of the longitudinal axes of the layers does not necessarily have to be in opposite directions, but can be in the same direction. This offset can also be introduced into one or more structural layers to transmit compressive forces along a diagonal direction (the product of direction A and direction c1 or c2) to force the wall to undergo specific deformation.

[0108] Figure 5A microscopic view of the cross-section of the 3D printed structure is shown, illustrating three examples of walls 70, 80, and 81, each with a first end 71 and a second end 72. Each wall 70, 80, and 81 has multiple flexible layers 73 and multiple structural layers 74, with the structural layers 74 separated by the flexible layers. As can be seen from this figure, the material layers are bonded together, resulting in a somewhat uniform structure from the first end 71 to the second end 72, where each layer 73, 74 is fused together. It is clear here that the structural layers have a greater width (2W) than the flexible layers (W), which increases the stiffness of the structural layers 74, which is greater than the stiffness of the flexible layers 73.

[0109] Figure 6a –6c shows the individual layers of the 3D printed structure, in which Figure 6a The first layer 90 is shown. Figure 6b The second layer 91 is shown, and Figure 6c The third layer 92 is shown. When a 3D printed structure is constructed via 3D printing, the first layer 90 can be considered as the base layer, the second layer 91 can be positioned on top of the first layer 90, and the third layer 92 can be positioned on top of the second layer 91. If a fourth layer is to be added to the 3D printed structure, the fourth layer may, for example, have the same structure as the first layer.

[0110] like Figures 6a-6c As shown, each layer has a continuous line 94 that follows a zig-zag pattern from the right side 95 to the left side 96 of layers 90, 91, and 92. This construction can be formed such that the line constitutes multiple hexagons 97, each hexagon having six walls 98. Two adjacent hexagons 97a, 97b to one hexagon are printed such that there are two walls 98a, 98a' separating hexagons 97a and 97b, while four of the adjacent hexagons 97c (only two of which have reference numerals) have a single wall separated from the first hexagon 97. Thus, two walls in a single layer constitute a structural layer because the two walls 98a, 98a' are bonded to each other and have higher stiffness than a single wall. Therefore, hexagons separated only by single walls 98b, 98c, 98e, and 98f constitute flexible walls.

[0111] Then as Figure 6b The next layer, the second layer 91, is produced in such a way that the structure of layer 91 is rotated 60 degrees relative to the first layer 90. This means that the two walls that were previously on the two walls of the hexagon are now located on the flexible wall. Figure 6a The top of 98b, 98e) is such that the second structural layer 91 is now adjacent to the flexible layer in the longitudinal direction of the wall (axis A in Figure 1).

[0112] Then as Figure 6cThe next layer, the third layer 92, is produced in such a way that the structure of layer 92 is rotated 60 degrees (α) relative to the second layer 90 (and 120 degrees relative to the first layer 90). This means that the two walls 98a and 98a' that were previously on the two walls of the hexagon are now located on the flexible wall. Figure 6a The top of 98c-98e) makes the structural layer of the second layer 91 now adjacent to the flexible layer in the longitudinal direction of the wall (axis A in Figure 1).

[0113] Therefore, a hexagonal lattice can be constructed by adding layers on top of each other and rotating the layers by a certain angle, wherein the hexagonal walls have, for example... Figure 1a The structure shown has a first-level structural layer and first and second flexible layers along axis A. Axis A can be considered perpendicular to... Figures 6a-6c The axes of the two-dimensional plane shown are such that the longitudinal axis of the wall rises from the plane of the figure toward the reader.

[0114] Figure 7a and 7b It shows Figures 6a-6c The diagram discloses a perspective view of the process, where the leftmost structure shows the first layer 100 of the 3D printed structure, wherein the double walls 101 have a first angle and have two adjacent single walls 103. In the second structure from the left, the second layer 102 is positioned on top of the first layer 101, where the double walls 101 are now adjacent to the single walls 103 by rotating the structure of the layer by 60 degrees, and the single walls 103 are now on top of the double walls in the first layer. The third structure from the left shows the third layer 104 positioned on top of the second layer 102, where the double walls are now positioned on top of the single walls 103 of the second layer 102, and the single walls 103 of the third layer are positioned on top of the double walls 101 of the second layer. The fourth structure from the left now shows how the fourth layer 105, having a structure to some extent the same as the first layer, is positioned on top of the third layer, such that the double walls 101 are positioned on top of the single walls 103, and the single walls 103 of the fourth layer are positioned on top of the double walls 101 in the third layer.

[0115] By rotating the double walls at each height to provide layers on top of each other as shown in Figure 1, a structure as shown in Figure 1 can be constructed. Figure 5The wall shown consists of a structural layer (double wall) followed by a flexible layer (single wall). Rotation can be performed in different ways, with different rotations and structures provided for each layer to achieve the desired wall structure. Furthermore, layers can be rotated in different ways when the lattice has different shapes; for example, for a triangular lattice, the rotation could be a product of approximately 120 degrees, and for a rectangular shape, the rotation could be, for example, a product of 90 degrees, to obtain a certain structure. If the lattice shape is circular, rotation can be performed at any angle to obtain the structure. Therefore, the rotation of the layers can be adjusted based on the shape of the lattice or the wall structure of the 3D printed structure.

[0116] Figure 8 A schematic cross-sectional view of the structure of the perforated grid 200 is shown, illustrating three adjacent walls 201, 202, and 203 attached to each other in direction C. Each wall has a structural layer 204, followed by two flexible layers 205 and 206, arranged in a repeating pattern in the direction of axis A. In other embodiments, any of the walls shown in the foregoing embodiments can be utilized to obtain certain patterns, wall structures, and adjacent walls. In one embodiment, the pattern of the adjacent walls can be any suitable pattern, wherein, for example, it can be provided in one wall. Figure 1a The pattern of the structural and flexible layers shown is illustrated, wherein adjacent walls may have, for example... Figure 1b 1c or Figure 4 The pattern shown. Therefore, a wall with a specific pattern is not required, and the pattern can be adjusted for a specific application, with one wall having a first stiffness and the other wall having a second flexibility that may be higher or lower than the first wall.

[0117] When viewed along axis C Figure 8 When 3D printing a structure, it can be seen that each layer of the material of the structure has a second axis E, and each layer has at least one structural layer 204 and a first flexible layer 205 and a second flexible layer 206. Therefore, the 3D printed structure can define a layer of walls in one layer, wherein one of the walls can have a structural layer with high rigidity, while two adjacent walls can have or have flexible walls on each side of the structural wall.

[0118] In addition, when observing Figure 8 When considering the structure, it can also be seen that the structure of the structural wall can be regarded as... Figure 8 The diagram shows a diagonal pattern along axis F. When moving in direction C, it can be observed that the structural layers are replaced by flexible layers 205, and the next structural layer 204 in the adjacent wall 202 is one layer lower than the first structural layer 204 of the first wall 201. The same statement can be made given that the third wall 203 in structural layer 204 is one layer lower than the previous structural layer 204 in the second wall 202. Therefore, viewed in three dimensions, the structural layers 204 follow a helical axis, where the structural layer of the adjacent wall is one layer lower than the previous wall.

[0119] In this embodiment, the structural layer 204 is adjacent to the flexible layer in the direction of axis A, and may also be adjacent to the flexible layer in the direction of axis E. Therefore, the structural layer 204 in the first layer 207 of the 3D printed structure 200 may have a flexible layer 205 adjacent to the structural layer 204 in the second layer 208 of the 3D printed structure 200. Furthermore, the second wall 202 may be provided with a flexible layer 205 adjacent to the structural layer 204 in the first layer 208. Additionally, the third wall 203 may be further provided with a flexible layer 205, which is adjacent to the flexible layer 205 in the first layer 208 in the direction of axis E.

[0120] The third layer 209 may also be provided with a flexible layer 205 or a structural layer 204 in the direction of axis A, which is adjacent to the flexible layer 205 or the structural layer 204 in the previous layer 208.

[0121] exist Figure 8 The wall of the embodiment shown can be considered as having a third axis F, wherein the third axis can be considered as a wall following a grid of holes (as in...). Figure 7a and 7b (Observed in a spiral manner). Therefore, the spiral axis F can extend obliquely downward in each wall, where the axis F intersects with the structural layer 204. When viewed from the side in two dimensions, Figure 8 The view shown is distorted. The helical axis can be viewed as a curve in three-dimensional space, and its shape can resemble a coiled spring or a handrail in a spiral staircase, where the helical axis moves downwards in a "screwing" manner, such as in the shape of a cylindrical spiral.

[0122] According to this application, exemplary embodiments of one, two, or three walls of the 3D printed structure should be understood as composable. That is, in a figure showing one wall, the same wall can be used as a second, third, or any subsequent wall or wall portion, as described. Based on the current description of the 3D printed structure, those skilled in the art will have no problem combining the disclosure of one embodiment with that of another.

[0123] The use of terms such as "first," "second," "third," and "fourth," "first level," "second level," and "third level," etc., does not imply any particular order but is intended to identify individual elements. Furthermore, the use of terms such as "first," "second," "third," and "fourth," "first level," "second level," and "third level," etc., does not indicate any order or importance; rather, these terms are used to distinguish one element from another. Note that the terms "first," "second," "third," and "fourth," "first level," "second level," and "third level," etc., here and elsewhere, are used solely for labelling purposes and are not intended to indicate any particular spatial or temporal order.

[0124] Furthermore, the marking of the first element does not imply the existence of the second element, and vice versa.

[0125] Although features have been shown and described, it should be understood that they are not intended to limit the claimed invention, and it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the specification and drawings should be considered illustrative rather than restrictive. The claimed invention is intended to cover all alternatives, modifications, and equivalents.

Claims

1. A 3D-printed structure of an elastic material having at least a first wall and a second wall, the first wall and the second wall being configured to deform when a force is applied to the first wall and / or the second wall in a first axial direction, and being configured to return to their original shape when the applied force is released, the 3D-printed structure comprising: At least a first layer, having a first wall portion and a second wall portion of the first layer, wherein the first wall portion of the first layer is a main structural layer and the second wall portion of the first layer is a first flexible layer. At least a second layer, having a first wall portion and a second wall portion of the second layer, wherein the first wall portion of the second layer is a second flexible layer, and the second wall portion of the second layer is a secondary structural layer or a third flexible layer. The first layer is adjacent to the second layer along the first axial direction. The main structural layer and the secondary structural layer have a first stiffness, and the first flexible layer, the second flexible layer and the third flexible layer have a second stiffness, wherein the first stiffness is greater than the second stiffness.

2. The 3D printed structure according to claim 1, wherein, The 3D printed structure includes a third wall.

3. The 3D printed structure according to claim 2, wherein, The first layer also includes a third wall portion of the first layer, wherein the third wall portion of the first layer is a flexible layer or a structural layer.

4. The 3D printed structure according to any one of claims 2-3, wherein, The second layer includes a third wall portion of the second layer, wherein the third wall portion of the second layer is a flexible layer or a structural layer.

5. The 3D printed structure according to any one of claims 2-3, wherein, The first wall is adjacent to the second wall and / or the third wall is adjacent to the second wall.

6. The 3D printed structure according to claim 1, wherein, The first flexible layer, the second flexible layer, the main structural layer and / or the secondary structural layer have a first surface and a second surface.

7. The 3D printed structure according to any one of claims 1-3, wherein, The first stiffness and / or the second stiffness are in the longitudinal direction.

8. The 3D printed structure according to any one of claims 1-3, wherein, The first stiffness and / or the second stiffness are in the lateral direction.

9. The 3D printed structure according to any one of claims 1-3, wherein, The first stiffness and / or the second stiffness are along the rotation direction.

10. The 3D printed structure according to any one of claims 1-3, wherein, The elastic material is a silicone resin material or a mixture of silicone resin materials.

11. The 3D printed structure according to any one of claims 1-3, wherein, The main structural layer is made of a first material composition, and the first flexible layer, the second flexible layer and the third flexible layer are made of a second material composition, wherein the first material composition is different from the second material composition.

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