IPC分类号：
A43B13/18 | A43B13/04 | A43B13/12 | B33Y80/00
国民经济行业分类号：
C1954 | C1953 | C1952 | C1951 | C2444 | C1761 | O8192 | C1959
当前申请(专利权)人地址：
INDUSTRIVEJ 5, 6261, BREDEBRO, DENMARK
发明人：
MITCHELL, JOSEPH HENRY | CARLUCCI, PATRIZIO
摘要：
A 3D printed structure of an elastic material may be provided. In one implementation, the 3D printed structure may include at least a first wall having a plurality of layers extending along a first axis. The first wall may include at least a primary structural layer, a first flexible layer, and a second flexible layer. The primary structural layer may have a first rigidity and at least one of the first flexible layer or the second flexible layer may have a second rigidity, the first rigidity being greater than the second rigidity.
技术问题语段：
The patent text discusses the problem of inflexibility in 3D printed structures due to the stiff material used for printing. The text highlights attempts to create flexible layers using foam-like substances, but issues exist such as reduced flexibility with increased strength and difficulty in achieving individualization without high costs. Therefore, there is a need for improved structures for individualization of flexible structures.
技术功效语段：
This patent describes a method for adjusting the rigidity and number of layers in a 3D printed structure to meet different needs. By increasing the number of flexible layers for walls that require less force to yield and increasing the number of structural layers for walls that require better resistance to compressive force, the rigidity of the first wall can be altered. Additionally, having walls abut each other allows for a transfer of rigidity between them, creating a cooperative effect in the overall structure.
权利要求：
1. A 3D printed structure of an elastic material, the 3D printed structure comprising:
at least a first wall configured to deform when a force is applied to the first wall in a direction of a first axis and configured to return to an original form of the first wall when the applied force is released, wherein the first wall has a plurality of layers extending along the first axis, the first wall comprising at least a primary structural layer, a first flexible layer, and a second flexible layer,
wherein the primary structural layer has a first rigidity and at least one of the first flexible layer or the second flexible layer has a second rigidity, wherein the first rigidity is greater than the second rigidity.
2. A 3D printed structure according to claim 1, wherein the primary structural layer abuts the first flexible layer and the second flexible layer along the first axis.
3. A 3D printed structure according to claim 1, wherein the primary structural layer and the at least one of the first flexible layer or the second flexible layer are configured to have the first rigidity and the second rigidity, respectively, in a longitudinal direction.
4. A 3D printed structure according to claim 1, wherein the primary structural layer and the at least one of the first flexible layer or the second flexible layer are configured to have the first rigidity and the second rigidity, respectively, in a transverse direction.
5. A 3D printed structure according to claim 1, wherein the primary structural layer and the at least one of the first flexible layer or the second flexible layer are configured to have the first rigidity and the second rigidity, respectively, in a rotational direction.
6. A 3D printed structure according to claim 1, wherein a width of the primary structural layer is larger than a width of the at least one of the first flexible layer or the second flexible layer.
7. A 3D printed structure according to claim 1, wherein the first wall further comprises at least one of a secondary structural layer or a third flexible layer.
8. A 3D printed structure according to claim 1, wherein the first wall has a repeating layered structure along a longitudinal axis of at least one of the primary structural layer, the first flexible layer, or the second flexible layer.
9. A 3D printed structure according to claim 7, wherein the primary structural layer and the secondary structural layer are separated by at least the first flexible layer.
10. A 3D printed structure according to claim 1, wherein the height of the primary structural layer is substantially similar to the height of the at least one of the first flexible layer or the second flexible layer.
11. A 3D printed structure according to claim 1, wherein the primary structural layer is separated in a longitudinal direction by two or more flexible layers.
12. A 3D printed structure according to claim 1, wherein the first wall has a first height extending between a first end of the first wall and a second end of the first wall, wherein the primary structural layer is positioned a distance of at least 20% of the first height from the first end of the first wall.
13. A 3D printed structure with according to claim 1, wherein the first axis intersects a central axis of the primary structural layer.
14. A 3D printed structure according to claim 1, wherein the elastic material is a silicone material or a mixture of a silicone material.
15. A 3D printed structure according to claim 1, wherein the primary structural layer is made from a first material composition the at least one of the first flexible layer or the second flexible layer is made from a second material composition, wherein the first material composition is different from the second material composition.
16. A 3D printed structure according to claim 1, wherein the first wall has a first height extending between a first end of the first wall and a second end of the first wall, wherein the primary structural layer is positioned a distance of at least 20% of the first height from the second end of the first wall.
17. A 3D printed structure according to claim 1, wherein the first axis intersects a central axis of the at least one of the first flexible layer or the second flexible layer.
技术领域：
[0001]A 3D printed structure of an elastic material, the 3D printed structure comprising: at least a first wall having a plurality of layers extending along a first axis, the first wall comprising at least a primary structural layer and a first flexible layer and a second flexible layer,
背景技术：
[0002]A common issue with 3D printed structures is that such kinds of structures are often made out of a relatively stiff material, which means that the structure of the 3D printed structure may be relatively inflexible due to the composition of the material that is used for printing.
[0003]CN 105034361 discloses a honeycomb core containing cells of different thicknesses and different shapes, and at least part of the wall thickness of the obtained honeycomb unit is gradually increased in the direction along the center of the honeycomb unit toward both ends of the honeycomb unit, so that the honeycomb clamp can be added. The contact area of the core and the panel, and the honeycomb core can be a flat or curved structure to meet the requirements of the nonlinear curved structure, where the honeycomb core has an excellent bending and compression resistance.
[0004]EP 3 213 909 discloses an impact resistant sandwich structure architecture for high speed impact resistant structure, comprising sandwich skins which enclose a sandwich core formed by a plurality of spacing layers and a plurality of trigger layers, wherein these layers are stacked alternatively in the core.
[0005]These types of material are widely used for providing stiffening in the aerospace industry, where these materials are intended to maintain their shape during application of an external force.
[0006]However, in order to attempt to get structures that have a compressibility and flexibility, there have been made numerous attempts to construct a material that has the desired flexibility while still maintaining the structural integrity of the material. Due to the flexibility and the weight of the material used for printing it may be a difficult task to create a layered construction that can achieve a controlled flexibility and counterforce within multiple different and very specific areas. Further difficulties may arise when there are multiple areas in the 3D printed structure that need to have differing flexibility or counterforce.
[0007]Such flexible layers have often been made using a foam like substance, such as a PU foam, where the foam can maintain a certain form while still having a certain flexibility, such as cushions for seats, midsoles for shoes, padding for luggage, etc. One issue with this kind of flexible layers is that the flexibility of the layers reduces when the structural strength of the materials is increased, where this also increases the weight of the material. Furthermore, the formation of this kind of material is often done in large molds, where any individualization of the material, such as specialized contouring often requires material to be cut away, and the foam to be sculpted after manufacturing, as the cost of an individualized mold is too high for it to be a viable option for personal individualization for each user.
[0008]Thus, there is a need to for improved structures for individualization of flexible structures.
发明内容：
[0009]In accordance with the present description, there is provided a 3D printed structure of an elastic material, the 3D printed structure comprising: at least a first wall configured to deform when a force is applied to the wall in a direction of a first axis and configured to return to its original form when the applied force is released, where the wall has a plurality of layers extending along the first axis, the first wall comprising at least a primary structural layer and a first flexible layer and a second flexible layer, where the primary structural layer has a first rigidity and the first flexible and/or the second flexible layer has a second rigidity, where the first rigidity is larger than the second rigidity.
[0010]Within the context of the present description, the term rigidity may be understood as a rate of flexibility, where the measurement may be made of a stiffness of a layer, a rate of yield, hardness (i.e. in the understanding when a harder layer has a higher rate of rigidity than a softer layer). The rigidity of a certain layer should be understood as the capability, aptitude or ability of a layer to flex in a certain direction. An alternative representation of the rigidity, may e.g. be the flexibility of the layers, where the primary structural layer (or any subsequent structural layer) may have a first flexibility, and the first and/or the second flexible layer (or any subsequent flexible layer) may have a second flexibility, where the first flexibility may be lower than the second flexibility. The rigidity may be seen as a quantification of the extent of how the layer resists in deformation in response to an applied force. The term flexible may be a complementary concept to the rigidity, i.e. the more flexible the layer is the less rigid it is.
[0011]Within the understanding of the present disclosure the term “layer” may be understood as a two-dimensional plane of a three-dimensional structure. The layer may comprise one or more walls that intersect the two-dimensional plane. Within the understanding of the present disclosure a “wall” may be understood as a two-dimensional plane of a three-dimensional structure, where the two-dimensional plane may be parallel to the wall and may intersect a plurality of layers of the three-dimensional structure. Within the understanding of the present disclosure a first layer of a wall may abut a second layer of a wall, which may abut a third layer in a wall. Thus, a wall may be seen as a structure having two or more layers stacked on top of each other, or stacked below each other.
[0012]The term “structural layer” is intended to differentiate from other layers in the wall structure, and where the term “flexible layer” is intended for naming of layers that are not seen as the structural layer, in order to differentiate the structural layer from different layers in the wall structure, i.e. the flexible layers. The presence of a structural layer and at least one flexible layer in a wall structure does not exclude other types of layers in the wall structure, having different properties than the two layers that are defined as being structural and/or flexible layers.
[0013]The primary structural layer, the secondary structural layer, the tertiary structural layer or any other structural layer may have a first rigidity. All the structural layers may have a first rigidity, where the first rigidity is higher than the second rigidity. The first flexible layer, the second flexible layer, the third flexible layer and/or any other subsequent flexible layer may have a second flexibility, where the second flexibility may be lower than the first flexibility.
[0014]In one embodiment, all structural layers in one wall and/or more walls may have the same flexibility. In one embodiment all flexible layers in one wall and/or more walls may have the same flexibility.
[0015]The provision of a first wall being provided in an elastic material, means that when a force is applied to the wall in a direction of the first axis, the wall is capable of absorbing the force, causing the wall to collapse. The force may be seen as being a compressive force, where the force up to a predetermined level may cause the first wall to compress without the wall being deformed away from the first axis. I.e. the wall may maintain its shape up to a certain amount of force. However, when a predetermined threshold of force is a surpassed, i.e. where a force higher than the threshold is applied to the wall, the wall may deform out of shape, so that one or more layers of the wall may translate in a direction that is different from the direction of the first axis, i.e. in a direction that may e.g. seen as being orthogonal to the first axis. Thus, the wall may be seen as being bent, or bulge 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, so that when the force is released/removed from the first wall, the first wall will return to its original shape. I.e. the elastic material will provide a resilient wall structure, where the wall will return to its original form after being compressed. Thus, the first wall, or any subsequent wall may be seen as being resilient. The wall may be seen as having an uncompressed state, a compressed state, and an intermediate state which may be seen as a state of the wall where a compressive force is applied to the wall, but where the wall has not reached its fully compressive state.
[0016]The wall may have a first end which may be seen as the top part of the wall, and a second end, which may be seen as the bottom part of the wall, where the wall is provided with a plurality of layers between the first end and the second end. When there is no compressive force applied to the wall, the wall may have a first length where the first length is substantially the summation of the height of each layer of the wall. When a compressive force is applied to the wall in a direction that is parallel to the first axis the wall may have a second height, where the second height is lower than the summation of the height of each layer.
[0017]This means that the wall of the 3D printed structure may have areas in the direction of the first axis that have higher rigidity than other areas, that are positioned in other positions along the first axis. The higher rigidity allows the primary structural layer, or any other structural layer of the first wall, to be less likely to be deformed than the flexible layer which has a reduced rigidity, compared to the structural layer. This therefore means that when a compressive force (in the direction of the first axis) is applied to the wall, where the compressive force is above a predefined force, the compressive force applied to the layers will compress the wall, where the wall will have a predisposition to give in to the compression force, where the wall is allowed to buckle or bend due to the compressive force. Due to the difference in rigidity of the different layers, the compressive force will cause the layer having less rigidity to yield prior to the layer having increased rigidity, meaning that the bend and/or buckling of the wall will occur in predefined areas, where the layers having less rigidity will deflect away from the first axis, before the layers having the increased rigidity.
[0018]The rigidity and the number of layers may be adjusted in accordance with the requirements of the 3D printed structure, where the number of flexible layers may be increased for a wall having a lower requirement of force required for allowing the first wall to yield, while an increased number of structural layers may be applied in order to improve the resistance to the compressive force. Thus, by the change of the ratio of flexible layers vs. structural layers, it is possible to alter the rigidity of the first wall.
[0019]In one exemplary embodiment of the present disclosure the 3D printed structure may be a 3D printed flexible structure. The 3D printed structure may be a structure which may be seen as shock absorbing, where the 3D printed structure is configured to absorb a force that is applied to the 3D printed structure. The shock absorption may be provided in the form that the 3D printed structure absorbs an energy of a force applied to the 3D printed structure, where the 3D printed structure may elastically deform to absorb the energy. When the force is released the energy may be released when the elastic deformation is reversed.
[0020]The 3D printer structure, and the walls of the 3D printed structure may have an original shape, which may be understood as their permanent shape, and a deformed shape, which may be seen as a temporary shape, where the deformed shape may be seen as a shape created by an external stimulus such as an external force or an external application of mechanical energy to the 3D printed structure and/or parts of the 3D printed structure.
[0021]In one embodiment of the present invention the 3D printed structure may be a 3D printed structure adapted to absorb a force generated by a human body. The 3D printed structure may be used as a dampening structure between a part of a human body and another entity, i.e. a rigid structure, such as part of a sole assembly in a shoe, a sitting area on a seat, a pad between a rucksack and the body of a user, a mattress, and similar structures that may be used to absorb and distribute energy transferred from a human body to another entity.
[0022]Within the understanding of the present invention the term “elastic material” should be understood as a term meaning that the elastic material is capable of stretching, or compressing without plastic deformation. I.e. where the elastic region of a stress-strain curve is larger than the plastic region of the stress strain curve. I.e. 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.
[0023]The term “elastic material” may mean a material that has at least a 50% elongation, or specifically more than 100% elongation, or specifically more than 200% elongation, or specifically more than 300% elongation. The term percent elongation (elongation %) is a measurement that captures the amount a material will plastically and elastically deform up to fracture. Percent elongation is one way to measure and quantify the ductility of a material. The material's final length is compared with its original length to determine the percent elongation and the material's ductility.
[0024]The elastic material used for the provision of the layers may be a material that has a Shore A hardness of between 30 and 80. The 3D structure however, may have a combined lower Shore A hardness than the elastic material, as the material may be made of a number of walls of layered material that may be separated from each other. Thus, the hardness of the structure may be a combination of the hardness of the walled structures and the spacing between the walls. Furthermore, due to the yield ability of the walls, the wall may deflect or bend at rates that are lower than at a hardness of the elastic material. Hence, the individual layers may be stable in the direction of compression force, where the layers compress minimally on an individual basis at the force which they are subjected to.
[0025]The order of the structural layer and the first flexible layer and the second flexible layer may be the primary structural layer followed by the first and the second flexible layers, seen in the direction of the first axis. The order may also or alternatively be a first flexible layer followed by the primary structural layer, which in turn is followed by the second flexible layer. The order may also or alternatively be the first flexible layer, followed by the second flexible layer followed by the primary structural layer.
[0026]This means that when a force is applied in a direction parallel to the longitudinal axis the first and/or second flexible layers will deflect away from the longitudinal axis before the primary structural layer will deflect away from the longitudinal axis.
[0027]A wall having a structure of layers having identical layers along its entire length may have a somewhat predictable collapsing force, when a compressive force is applied to the wall in its longitudinal direction, but it may be nearly impossible to predict how the wall will collapse, as the collapse may be the direction of the force, when the force is not completely parallel to the longitudinal axis, that has a huge impact on how the wall may collapse or bend. Furthermore, another issue is that when the wall collapses, it may lose most of or all of its counterforce to the compressive force, so that the wall loses most of its opposing force as soon as it collapses, as it may fold and/or collapse completely.
[0028]However, by applying a structure of structural layers and flexible layers, that may e.g. be in a repeating structure along the longitudinal axis it is possible to predict where the first wall will give in to the compressive force, as the flexible layer may have a reduced stiffness and/or resistance to the force, so that the wall will in all likelihood deflect in the areas having the flexible layers, before it will deflect in the areas having the structural layers. Thus, it may be possible to have the wall collapse/deflect to the compressive force in a predictable way, which makes it easier to configure the wall to collapse at a certain force. Furthermore, this allows the wall to collapse or deflect in a controlled manner, so that the counterforce to the compressive force may be maintained by the structural parts of the wall, even though the flexible parts have deflected or have collapsed between the structural parts.
[0029]The first wall may be a part of a larger structure, where each layer of the wall may correspond to a layer of a larger 3D structure, and where the larger 3D structure may have a plurality of layers. The first wall may be part of a structure having a second wall, a third wall, or subsequent walls. The first wall may be part of a structure, where the first wall is a part of a cellular structure, where the first wall is part of a closed cell (seen from above), such as a circular, annular, triangular, hexagonal, or any suitable polygonal closed cell, where the first wall and/or a plurality of walls define the volume of a cell.
[0030]The structural layer may be any kind of structure that creates a wall having an increased rigidity compared to the flexible layers. The structural layer may comprise a plurality of layers in the direction of the first axis, where the layers may be stacked on top of each other, creating a part of a wall having an increased rigidity. The structural layer may have a height in the direction of the first axis that is similar or the same as the height of a first layer. However, the structural layer may alternatively have a height that is larger than the height of the flexible layer.
[0031]Within the context of the present disclosure the term wall may be replaced with the term wall part, when disclosing a part of the wall.
[0032]Thus, the walls and the structural layers may be utilized as a mechanical device which may be used to store energy and subsequently release it to absorb shock or to maintain a force between contacting surfaces (first end and second end of a wall).
[0033]In one or more embodiments the primary structural layer and/or the first and/or the second flexible layers may be attached to another layer via a boundary, where the boundary between the two layers may have a rigidity that is less than the rigidity of the primary structural layer and/or the flexible layer. This means that when the first wall deflects from the first axis, the deflection of the two layers may pivot across the boundary (seen in a cross-sectional view). This means that the layers may deflect in a predefined area, which means that the deflection of the first wall may be predicted and/or anticipated, which may assist in controlling the deflection by adjusting the rigidity of the layers, or the rigidity of the boundary between the layers.
[0034]In one or more embodiments the structural layer may have a first surface and a second surface. The first surface and/or the second surface of the structural layer may be seen as the part of the layer which intersects with the first axis, when the first wall is in an uncompressed state. The first surface and/or the second surface of the structural wall may be seen as the part of the layer which faces a preceding or subsequent layer of the first wall. Thus, the first surface and/or the second surface may have a tangential axis (seen in a cross-sectional view) that is substantially orthogonal to the first axis. The first surface and/or the second surface may be seen as the part of the layer that abuts another layer of the wall.
[0035]The uncompressed state of the first wall may be where the first axis intersects all the layers of the first wall and/or at least a plurality of the layers of the wall, when the wall is constructed in a linear manner, where each layer of the wall is stacked on top of each other along the first axis. The intermediate state of the first wall may e.g. be where the first axis intersects all the layers of the first wall and/or at least a plurality of the layers, where the compressive force may e.g. be too low to force one or more layers of the wall to deflect from the first axis. The compressed state of the first wall may be where at least one layer of the first wall is deflected away from the first axis.
[0036]In one exemplary embodiment the primary structural layer may abut the first flexible layer and the second flexible layer along the first axis. This means that the primary structural layer of a first wall may have a first flexible layer on a first side of the primary structural layer, and a second flexible layer on an opposite second side of the primary structural layer. Thus, the first axis may intersect a flexible layer, a structural layer and a flexible layer in this order along the length of the first axis. This allows the primary structural layer to be surrounded by flexible layers, i.e. on top and bottom, allowing the flexible layers to deform prior to the deformation of the structural layer when a force is applied to the first wall.
[0037]In one or more embodiments the flexible layer may have a primary surface and a secondary surface. The primary surface and/or the secondary surface of the flexible layer may be seen as the part of the layer which intersects with the first axis, when the first wall is in an uncompressed state. The primary surface and/or the secondary surface of the flexible wall may be seen as the part of the layer which faces a preceding or subsequent layer of the first wall. Thus, the primary surface and/or the secondary surface may have a tangential axis (seen in a cross-sectional view) that is substantially orthogonal to the first axis. The first surface and/or the second surface may be seen as the part of the layer that abuts another layer of the wall.
[0038]The layers of the first wall may fuse, bond, blend, integrate and/or merge where the boundary between two layers of the wall may be indistinguishable when the wall structure has been formed. However, during the 3D printing of the first wall or any subsequent wall, the wall is formed layer by layer, where one layer is positioned on top of a preceding layer (a layer that has already been formed and positioned) where a first surface of the preceding layer abuts a second surface of the subsequent layer (a layer that is positioned on top of the preceding layer). The positioning of the two layers may occur prior to curing, so that the first and the second surfaces intersect, and may be indistinct from each other. Alternatively, the first surface may bond or adhere to the second surface in a permanent manner, where the boundary between the two layers may be seen in microscopic view of a section of the first wall or any subsequent wall.
[0039]In one or more embodiments the rigidity may be in the longitudinal direction. The longitudinal direction may be a direction that is parallel to the first axis of the first wall. The rigidity of the layers of the first wall or any subsequent wall may be seen as a rigidity which represents the flexibility of the layer in the longitudinal direction. I.e. where the rigidity represents how the layer is predisposed of moving in a longitudinal direction. A high rigidity will mean that the layer may need an increased force to dispose the layer in a longitudinal direction, compared to a layer having a lower rigidity, and vice versa.
[0040]In one or more embodiments the rigidity may be in a transverse direction. The transverse direction may be a direction that is transverse to the first axis of the first wall. The rigidity of the layers of the first wall or any subsequent wall may be seen as a rigidity which represents the flexibility of the layer in the transversal direction. I.e. where the rigidity represents how the layer is predisposed of moving in a transverse direction. A high rigidity will mean that the layer may need an increased force to dispose the layer in a transversal direction, compared to a layer having a lower rigidity, and vice versa.
[0041]In one or more embodiments the rigidity may be in a rotational direction. The rotational direction may be a direction that rotates along a longitudinal axis of a layer first wall, where the longitudinal axis of a layer of the first wall may be substantially orthogonal (right angled) to the to the first axis of the first wall. Thus, the rigidity of the layers of the first wall or any subsequent wall may be seen as a rigidity which represents the flexibility of the layer in a rotational direction. Thus, when a compressive force is applied to the wall of the structure, the one or more layers may deflect away from the first axis of the wall, where a layer may be bonded to another layer, which means that the compression force will cause a torque to be applied to the layer or both layers. The rigidity of the layer may in a rotational direction may e.g. represent the connection between two layers, the rotational flexibility of a single layer. The flexibility in a rotational direction may be seen as the resistance to a twisting motion of the layer in response to an applied force, i.e. how the layer resists a rotational motion in response to an applied force. The rotational rigidity and/or stiffness may also be seen as the torsional rigidity, stiffness and/or flexibility.
[0042]In one or more embodiments the structural layer may have a width (transversal to the longitudinal axis) that is larger than of the thickness of the flexible layer.
[0043]The structural layer has a width (transversal to the longitudinal axis) that is more than 110%, 120%, 130%, or 150% of the thickness of the flexible layer. The structural layer may have a width that is about double the width of the flexible layer.
[0044]The structural layer may be formed as two or more layers of flexible material that abut each other in a transversal direction. This means that the two layers may be positioned in a single layer of the walled structure, and where each layer bonds to the preceding and/or subsequent layer of the structure as well as the layer beside in a transverse direction. Thus, the primary structural layer, or any subsequent layer may be constructed of two or more layers of material, where each layer is comparable to the flexible layer of the walled structure. The provision of two or more layers of material to form a structural layer will increase the rigidity of the layer of the wall, as the material may have an increased width, when the two or more layers are bonded to each other, as well as being bonded to the abutting layers in the longitudinal direction. The two abutting layers may have a height (in the longitudinal direction) that is comparable or the same as the height of the flexible layer, where the introduction of the abutting layer does not alter the height of the structural layer. Thus, the structural layer may have a similar or the same height as the flexible layer.
[0045]In one or more embodiments the first wall may have at a secondary structural layer and/or at least a third flexible layer. The secondary structural layer may be further provided to a wall of the 3D printed structure, in continuation of the primary structural layer and/or a flexible layer, where the further structural layer may be provided to increase the height of the wall and/or to increase the rigidity of the wall. A third flexible layer may further be provided to the wall of the 3D printed structure in continuation of the primary structural layer, secondary structural layer, first flexible layer and/or the second flexible layer, where the further flexible layer may be provided to increase the height of the wall and/or to decrease the rigidity of the wall. The first wall or any subsequent wall may be provided with a plurality of structural and/or flexible layers in order to provide a predefined length of the wall along the direction of the first axis.
[0046]In one or more embodiments the order of the structural layer and the flexible layers may be repeated along the first axis. This means that the order of the structural and the first and the second flexible layers may be reproduced along the length (along the first axis) the wall, where the primary structural layer and the secondary structural layers may be separated by one or more flexible layers, in one example, the two structural layers are separated by two flexible layers. Thus, the length of the wall may have a structure where a structural layer may abut one or two flexible layers on each side (above and below along the longitudinal length) where this order may be repeating along the length of the wall.
[0047]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.
[0048]This means that the flexible layers may be configured to defer from the compressive force which is applied to the first wall, in the areas that are between two structural layers, so that the wall can reduce in height from its first end to its second end.
[0049]In one or more embodiments the primary and the secondary structural layers may be separated by at least the first flexible layer. By separating the primary and the secondary structural layer with at least one flexible layer, it is possible to control the deformation of the first wall along its longitudinal axis, where the flexible layer, which has a lower rigidity than the structural layer will deform prior to the deformation of the structural layers. Thus, it is possible to predict more precisely on how the first wall deforms, and it is therefore possible to adjust the rigidity of the structural layer, and/or any walls surrounding the first wall, to provide a first wall having a predictable and controllable collective rigidity of the entire wall on its own.
[0050]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 in a similar height as the flexible layer, where in one or more embodiments the height of the structural layer is the same as the flexible layer, it may be possible to exchange a structural layer with a flexible layer, and vice versa, during the construction of the wall, without having to recalibrate the total height of the wall due to the exchanging of one structural layer with a flexible layer, or vice versa. Thus, the length in the direction of the first axis (height or total height) of the wall to be manufactured/printed may be defined out of the total number of layers, where the specific number of the specific layers does not influence the length of the wall, and the specific type of layer can be interchanged without specific modification and calculation of the total length of the wall. This also means that the introduction of a structural wall can be done selectively in any position in a layer of the article to be 3D printed, without influencing subsequent layers of article, and there is no need to compensate for the structural layer in a subsequent layer of the wall.
[0051]In one or more embodiments the primary structural layer may be separated in the longitudinal direction by two or more flexible layers. By separating the primary structural layer with two or more flexible layers, it means that in the longitudinal direction (direction of the first axis) the primary structural layer is followed by at least two flexible layers. This means that the at least two flexible layers provide the wall with a zone (in the longitudinal direction) that may be seen as more flexible (less rigid) allowing the wall to collapse in this zone in an easier manner. Thus, the provision of two flexible layers abutting each other in the direction of the first axis, may also mean that the flexibility of the bond between the two layers is less than between a structural layer and a flexible layer, which may mean that one flexible layer may deflect easier from the other flexible layer, when a compressive force is applied to the wall in the direction of the first axis.
[0052]In one or more embodiments the first flexible layer may abut the primary structural layer. By having a primary structural layer abut a first flexible layer, in the direction of the first axis, the flexibility of the wall may be increased in the direction of the first axis. The flexible layer will have a lower rigidity that the structural layer, so that the total rigidity of the two layers combined will be less than having e.g. two structural layers abutting each other. Thus, it is possible to increase the flexibility of the wall by a provision of a flexible wall, without changing the composition of the material used for 3D printing.
[0053]In one or more exemplary embodiments the first wall, the second wall, third wall or any subsequent wall may have a first height and a first end and a second end, where a primary structural layer is positioned at least a distance of 20% of the first length from the first end and/or at least a distance of 20% 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 one example where the first wall has a height of 10 mm, a primary structural layer may be positioned in an area that is between 2 and 8 mm of the height of the first wall. This means that the wall may have a structural layer that is positioned in a central region of the wall. Therefore, a central area of the first wall may have both a first and second flexible layers as well as a structural layer. Thus, it may be possible to control the deformation of the first wall when a force is applied to the wall. In a second example the central region of the first wall may have two or more structural layers, where the structural layers may be separated by one or more flexible layers.
[0054]In one or more embodiments the first axis may intersect a central axis of the structural layer and/or the flexible layer. This means that the first wall may be provided in such a way that the structural and flexible layers are provided in a linear manner, where each layer is stacked on top of each other in a direct manner, so that any compression force that is applied to the first wall in a direction parallel to the first axis, is transmitted through all the layers of the wall that have a central axis that intersects the first axis. The central axis of the layers may be seen as a longitudinal axis that follows the length of the layer, and may be seen as perpendicular to a cross sectional plane of the layer.
[0055]In one or more embodiments the elastic material may be a silicone material or a mixture of a silicone material. The 3D printing may be done by adding one layer on top of another layer, and continuing this until the wall has a desired height. The 3D printing may advantageously be done using a liquid form polymer, that cures when it has been positioned in its correct position. Thus, the 3D printed structure may be made of a polymeric material when cured. An example of this is a liquid silicone polymer, that is added in the same direction as the layer which it is positioned on top of, so that a wall may be a number of discrete lines of polymer added on top of each other, where the lines are parallel to each other when 3D
具体实施方式：
[0098]FIG. 1 shows a first exemplary embodiment of a 3D printed structure 1 seen in a schematic sectional view, having a first wall 2 having a plurality of layers extending along a first axis A. The first wall 2 comprises a primary structural layer 3, a first flexible layer 4 and a second flexible layer 5. In this exemplary embodiment, the first wall 2 comprises a secondary structural layer 6, a tertiary structural layer 7 and a quaternary structural layer 8, where the secondary 6 and the tertiary 7 structural layers, as well as the tertiary 7 and quaternary 8 structural layers each are separated by two flexible layers 9, 10, 11, 12, respectively. I.e. where the structure of the primary structural layer 3 and the first and 3 the second 4 flexible layers is repeated along the length of the wall 2 in the longitudinal direction A of the wall 2.
[0099]The primary structural wall 3 and the first 4 and second 5 flexible walls, as well as the subsequent walls, are 3D printed using an extruded line of flexible material having a height H and a width W, and where one layer of material in the 3D printed structure may be the height H, and may be applied in a continuous manner as required in the 3D printed structure.
[0100]In this embodiment, the structural layer 6 in this wall 2 are provided as two separate lines 12, 13 of extruded flexible material, where the two separate lines 13, 13′ are joined to each other at a joining side wall, where the joining side wall 14 provides a permanent bond between the two lines 13, 13′ of material. Furthermore, the structural layer 6 may be joined to at least one flexible wall 5, 9 where an upper 15 or a lower 16 wall of the flexible wall may be joined to an upper or lower wall of the structural layer 6, creating a permanent bond between the two layers. The bond between the layers may extend along the entire length of the layer 6, 5, 9 along an axis B which is substantially perpendicular to the 2D plane represented in the present sectional view. The flexible layers 9, 10 may also be bonded along the entire length of the layer 9, 10. As seen in this embodiment, the structural layer 6, has a width that is approximately twice the width (2W) of the flexible layer 5, 9 (W). The width of the structural layer 6, ensures that the layer has a higher rigidity than the flexible layers 5, 9, so that when a compressive force is applied in the direction of the first axis A to the wall 2 the structural layer 6 will resist deformation for a longer time than the flexible layer. The same considerations may be made for all the structural and flexible layers shown in FIG. 1a.
[0101]Similarly, FIG. 1b shows another exemplary embodiment of a wall 20, where the wall comprises a primary structural layer 21, a secondary structural layer 22, as well as six flexible layers 23, 24, 25, 26, 27, 28 that separate the primary structural layer 21 from the secondary structural layer 22, in a direction of the first axis A. Two more flexible layers are provided below the secondary structural layer 22. In this embodiment, the number of flexible layers is increased in view of the embodiment shown in FIG. 1a, which means that collective rigidity of the wall 20 is less than the wall 2 shown in FIG. 1a, assuming that the two walls are manufactured in a similar manner, of a similar material and similar dimensions as the lines of flexible material having a similar height (H) and width (W). The increase in flexibility is due to the fact that the wall has more flexible layers per unit of length along the axis A, than the wall 2 in FIG. 1a. Thus, when a compressive force is provided in the direction of axis A, the structural layers 21, 22 will resist deformation while any one of the flexible layers 23, 24, 25, 26, 27 may deform prior to the structural layers 21, 22.
[0102]FIG. 2a shows a wall 30 having three structural layers 31, 32, 33 that are separated from each other by a first set of three flexible layers 34, 35, 36 and a second set of flexible layers 37, 38, 39. When the wall 30 is in its uncompressed state the first axis A intersects a central part of each layer, so that the wall 30 may have a substantially straight shape.
[0103]An increase in compression force in the direction of the axis A will cause a deformation of the flexible material of the layers 34, 35, 36, 37, 38, 39 causing the shape of the wall 30 to change due to the flexibility of the material, and with an increase in compressive force, the wall 30 will eventually deform in such a way that the wall will bend away from the first axis A. In the assumption that the first end 40 of the wall and the second end of the wall 41 are in a fixed in position, the deformation of the wall will most likely occur in a central part 42 of the wall 30, where the central part 42 of the wall 30 will deflect away from the first axis A. As the wall is made up of layers having different rigidity, it is highly likely that the parts of the wall having a lower rigidity, such as the flexible layers 34, 35, 36, 37, 3839 will be the first areas that will deform, and therefore cause the deflection of the wall from the axis A in the areas of the flexible layer 34, 35, 36, 37, 38, 39 where the structural layers 31, 32, 33 will resist the deformation up to a certain point. One example of the deformation may be seen in FIG. 2b, where two flexible layers 35, 38 have deflected in a transverse direction C, where both layers have deflected in the same direction c1, causing the length of the wall to reduce from its initial length X to its compressed length Y, as may be seen in FIG. 2b.
[0104]In FIG. 2c, the same situation is shown, where a compression force has to be applied to the wall 30, where the flexible layer 35 deflects in the direction c1 and the flexible layer deflects in the direction c2. The directions c1 and c2 are only shown as examples, and the flexible layers can deflect in the same direction, opposite directions, or alternate directions. A similar deflection may occur when the number of flexible layers is only two, where the flexible layer may deflect in a direction away from the first axis A in a direction shown by the axis C.
[0105]FIG. 3 shows another embodiment of a 3D printed structure 1, seen in a schematic, having a schematic sectional view, having a wall 50, where the wall comprises at least a primary structural layer 51, and a first flexible layer 52 and a second flexible layer 53. The wall further comprises a secondary structural layer 54, as well as four additional flexible layers 55, 56, 57, 58. Each of the layers of the wall 50 has a longitudinal axis D, which extends along the centre of the layer along the length of each layer.
[0106]The 3D printed structure shown in FIG. 3, is formed so that the longitudinal axis D of the layers 51-58, is substantially centered along the length of the wall 50 in the direction of axis A, i.e. that the axis D intersects the longitudinal axis D of each of the layers. This means that when a compression force is applied to the wall 50 in a direction of the axis A, the force translates to the centre of each layer, and may assist the wall 50 in maintaining its height (X as shown in FIG. 2a) up to a predefined magnitude of compression force, before the flexible layers begin to deform and defer away from the longitudinal axis A, similar to what is shown in FIGS. 2b and 2c.
[0107]FIG. 4, shows a schematic sectional view of a wall 60, having three structural layers 61, 62, 63 and six flexible layers 64, 65, 66, 67, 68, 69, similar to what is shown in FIGS. 2a-2c. In this exemplary embodiment, the longitudinal axis D of flexible layers 65 and 68 has been offset in the direction c1 and c2 away from the longitudinal axis of the wall 60, where this offset of the longitudinal axis ensures that when a compression force is applied in the direction of the longitudinal axis A of the wall 60, the flexible layers 65 and 68 are predisposed or biased to deflect in the directions c1 and c2, allowing the wall 60 to bend in these directions. The offset of the longitudinal axis of the layers does not necessarily have to be in opposite directions, but may be in the same direction. The offset may also be introduced into one or more of the structural layers, in order to translate the compressive force in a diagonal direction (a product of direction A and direction c1 or c2) to force a specific deformation of the wall.
[0108]FIG. 5 shows a microscopic view of a sectional cut of a 3D printed structure, showing three examples of walls 70, 80 and 81, each having a first end 71 and a second end 72, where each wall 70, 80, 81 has a plurality of flexible layers 73 and a plurality of structural layers 74, where the structural layers 74 are separated by flexible layers. As may be seen in this figure, the layers of material bond with each other, creating a somewhat uniform structure from the first end 71 to the second end 72, where each layer 73, 74 are fused to each other. Here it is clear that the structural layer has a larger width (2W) than the flexible layers (W), which increases the rigidity of the structural layers 74 is higher than the rigidity of the flexible layer 73.
[0109]FIGS. 6a-6c show separate layers of a 3D printed structure, where FIG. 6a shows a first layer 90, FIG. 6b shows a second layer 91 and FIG. 6c shows a third layer 92. When the 3D printed structure is being constructed via 3D printing, where the first layer 90 may be seen as a base layer, the second layer 91 may be positioned on top of the first layer 90, and the third layer 92 may 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 e.g. have the same structure as the first layer.
[0110]As may be seen in FIGS. 6a-6c, each layer is has a continuous line 94 that follows a zig-zag pattern from the right side 95 to the left side 96 of the layer 90, 91, 92. The construction may be formed in such a way that the line creates a plurality of hexagons 97, where each hexagon has six walls 98. Two of the adjacent hexagons 97a, 97b to one hexagon are printed in such a manner that there are two walls 98a, 98a′ that separate the hexagons 97a and 97b, while, while four of the adjacent hexagons 97c (only two of these have reference numbers) have a single wall separating from the first hexagon 97. Thus, the two walls in a single layer create a structural layer, as the two walls 98a, 98a′ bond with each other and have a higher rigidity than the single wall. Thus, the hexagons that are only separated by a single wall 98b, 98c, 98e, 98f, create a flexible wall.
[0111]The next layer, i.e. the second layer 91, as shown in FIG. 6b, is then produced, in such a way that the structure of the layer 91 is rotated by 60 degrees, relative to the first layer 90, which means that the two walls, which were present on two walls of the hexagon, now lie on top of a flexible wall (98b, 98e of FIG. 6a), so that the structural layer of the second layer 91 now abuts a flexible layer in the longitudinal direction of the wall (axis A in FIG. 1).
[0112]The next layer, i.e. the third layer 92, as shown in FIG. 6c, is then produced, in such a way that the structure of the layer 92 is rotated by 60 degrees (α), relative to the second layer 90 (120 degrees rotation relative to the first layer 90), which means that the two walls 98a, 98a′, which were present on two walls of the hexagon, now lie on top of a flexible wall (98c-98e of FIG. 6a), so that the structural layer of the second layer 91 now abuts a flexible layer in the longitudinal direction of the wall (axis A in FIG. 1).
[0113]Thus, by adding layers on top of each other and rotating the layers a certain degree, it is possible to construct a hexagonal cell, where the walls of the hexagonal shape have a structure as shown in e.g. FIG. 1 a, where the wall has a primary structural layer, and a first and a second flexible layers in the direction of the axis A. The axis A may be seen as an axis that is a normal to the two dimensional plane shown in FIG. 6a-6c, where the longitudinal axis of the wall rises up from the plane of the drawings towards the reader.
[0114]FIGS. 7a and 7b show a perspective view of the process disclosed in FIG. 6a-6c, where the leftmost structure shows a first layer 100 of 3D printed structure, where the double wall 101 has a first angle, and has two neighbouring single walls 103. In the second structure from the left, a second layer 102 has been positioned on top of the first layer 101, where the double wall 101 now abuts a single wall 103 by rotating the structure of the layer 60 degrees, and where a single wall 103 now is positioned on top of the double wall in the first layer. The third structure from the left shows where a third layer 104 has been positioned on top of the second layer 102, where the double wall now is positioned on top of a single wall 103 of the second layer 102, and a single wall 103 of the third layer has been positioned on top of the double layer 101 of the second layer. The fourth structure from the left now shows how a fourth layer 105 having a structure that is somewhat identical to the first layer is positioned on top of the third layer, so that a double wall 101 is positioned on top of a single wall 103, and a single wall 103 of the fourth layer is positioned on top of a double wall 101 in the third layer.
[0115]By the provision of the layers on top of each other in the manner as shown in FIG. 1 by rotating the double wall in each height, it is possible to construct a wall as shown in FIG. 1-FIG. 5, where a structural layer (double wall) is followed by a flexible layer (single wall). The rotation may be done in a different manner, where each layer may be provided in different rotation and structure, so that the desired structure of a wall may be obtained. Furthermore, the rotation of the layers may be done differently, when the cells have a different shape, i.e. for a triangular shape of a cell, the rotation may be a product of about 120 degrees, for a rectangular shape, the rotation may be e.g. a product of 90 degrees, to obtain a certain structure. If the shape of the cells is circular, any angle may be utilized for rotation, to obtain a structure. Thus, the rotation of the layers may be adjusted in view of the shape of the cells or the walled structure of the 3D printed structure.
[0116]FIG. 8 shows a schematic cross-sectional view of a structure of a cell 200, showing three adjacent walls 201, 202, 203, that are attached to each other in the direction C. Each wall has a structural layer 204, followed by two flexible layers 205, 206, in a repeating pattern in the direction of the axis A. In other embodiments, any of the walls shown in the previous embodiments may be utilized, in order to obtain a certain pattern, structure of walls, as well as adjacent walls. In one embodiment, the pattern of adjacent walls may be any suitable pattern, where e.g. the pattern of structural and flexible layers shown in in FIG. 1a, may be provided in one wall, where the adjacent wall may have a pattern as e.g. shown in FIGS. 1b, 1c, or FIG. 4. Thus, there is no requirement of a specific pattern of walls, and this pattern can be adjusted for a specific application, where one wall has a first rigidity followed by another wall having another flexibility, that may be higher or lower than the first wall.
[0117]When viewing the 3D printed structure in FIG. 8 in the direction of axis C, it is possible to see that each layer of material of the structure has, having a second axis E, has at least one structural layer 204 and a first 205 and a second flexible layer 206. Thus, the 3D printed structure may in one layer may define a layer of a wall, where one of the walls may have a structural layer having a higher rigidity while the two adjacent walls may have, or on each side of the structural wall, may have a flexible wall.
[0118]Furthermore, when viewing the structure of FIG. 8, it is also possible to see that the structure of the structural walls may be seen as having a diagonal pattern, along the axis F, as shown in FIG. 8. When moving in a direction C it may be seen that the structural layer is replaced by a flexible layer 205, and the next structural layer 204 to the side, i.e. in the adjacent wall 202 is one layer lower than the first structural layer 204 of the first wall 201. The same may be stated in view of the third wall 203 in the structural layer 204 is one layer lower than the previous structural layer 204 in the second wall 202. Thus, seen in three dimensions, the structural layers 204 follow a helical axis, where an adjacent wall has a structural layer a layer lower than the previous wall.
[0119]In this embodiment a structural layer 204 abuts a flexible layer in the direction of axis A, and may also abut a flexible layer in the direction of axis E. Thus, a structural layer 204 in the first layer 207 of the 3D printed structure 200 may have a flexible layer 205 that abuts 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, which abuts the structural layer 204 in the first layer 208. Yet further, the third wall 203 may further be provided with a flexible layer 205, which abuts the flexible layer 205 in the first layer 208 in the direction of the axis E.
[0120]The third layer 209 may yet further be provided with a flexible layer 205 or a structural layer 204 in the direction of axis A, abutting a flexible 205 or a structural layer 204 in the previous layer 208.
[0121]The walls of the embodiment shown in FIG. 8 may be seen as having a third axis F, where the third axis may be seen as following the walls of the cells (as seen in FIGS. 7a and 7b in a helical manner. Thus, the helical axis F may extend diagonally downwards, where the axis F intersects a structural layer 204, in each wall. The view shown in FIG. 8 is distorted, as the view is seen from the side in two dimensions. The helical axis may be seen as a curve in three dimensional space, and may be similar in shape to a coiled spring, or similar to a handrail in a spiral staircase, where the helical axis moves downwards in a “screwing” motion, in the shape of e.g. a cylindrical helix.
[0122]In accordance with the present disclosure, the exemplary embodiments of one, two or three walls of the 3D printed structure is to be understood as being combinable. I.e. in a figure showing one wall, the same wall may be utilized as a second, third or any subsequent wall or wall part in accordance with the description. The person skilled in the art will not have any problem in combining disclosures of one embodiment with another embodiment based on the present description of the 3D printed structure.
[0123]The use of the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. does not imply any particular order, but are included to identify individual elements. Moreover, the use of the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. does not denote any order or importance, but rather the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. are used to distinguish one element from another. Note that the words “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. are used here and elsewhere for labelling purposes only and are not intended to denote any specific spatial or temporal ordering.
[0124]Furthermore, the labelling of a first element does not imply the presence of a second element and vice versa.
[0125]Although features have been shown and described, it will be understood that they are not intended to limit the claimed invention, and it will be made obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the claimed invention. The specification and drawings are, accordingly to be regarded in an illustrative rather than restrictive sense. The claimed invention is intended to cover all alternatives, modifications, and equivalents.