Shaped object and method for manufacturing the same
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KYORAKU CO LTD
- Filing Date
- 2022-02-22
- Publication Date
- 2026-08-05
Smart Images
Figure 0007900647000002 
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Abstract
Description
Technical Field
[0001] The present invention relates to a shaped object that can be manufactured by additive manufacturing and a method for manufacturing the same.
Background Art
[0002] Patent Document 1 discloses a method for manufacturing a shaped object having a three-dimensional network structure by laminating single-layer structures.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In Patent Document 1, each single-layer structure includes an outer peripheral line portion surrounding the outer periphery. Although this outer peripheral line portion contributes to improving the strength of the shaped object, providing the outer peripheral line portion may cause the surface of the shaped object to become unnaturally hard. Therefore, in applications where the entire shaped object is required to have a natural feel, such as a cushioning material (especially a cushioning material used for applications that come into contact with the body, such as the part corresponding to the insole or the leg of a prosthetic limb), it is not preferable to provide the outer peripheral line portion.
[0005] On the other hand, when the outer peripheral line portion is removed from the shaped object as in Patent Document 1, the ends of the linear resin constituting the single-layer structure are arranged at the outer peripheral portion of the single-layer structure. When the ends of the linear resin are provided at the outer peripheral portion of the single-layer structure, in a shaped object formed by laminating a plurality of single-layer structures, delamination of the shaped object is likely to occur starting from the ends.
[0006] The present invention has been made in view of such circumstances, and provides a shaped object capable of suppressing delamination of the shaped object while suppressing the shaped object from becoming unnaturally hard. [Means for solving the problem]
[0007] According to the present invention, a molded object is provided which is composed of a plurality of single-layer structures stacked together, wherein each of the plurality of single-layer structures is formed by applying a linear resin, and in at least one of the plurality of single-layer structures, the linear resin is folded back at a folding point provided on the outer periphery of the single-layer structure, and has a folded portion that is located inside the single-layer structure beyond the outer periphery, and the folded portion is the part between the end of the linear resin and the folding point.
[0008] In at least one single-layer structure included in the fabricated object of the present invention, the linear resin constituting the single-layer structure is folded back at a folding point provided on the outer periphery of the single-layer structure, and has a folded portion located inside the single-layer structure beyond the outer periphery. With this configuration, delamination of the fabricated object starting from the end of the linear resin is suppressed. In addition, since the outer periphery is unnecessary, the fabricated object does not become unnaturally hard.
[0009] The following are examples of various embodiments of the present invention. The embodiments shown below can be combined with each other. Preferably, the molded object is as described above, wherein the end portion is welded to the outer circumference. Preferably, a method for manufacturing a molded object comprising a plurality of stacked single-layer structures, wherein the single-layer structures are composed of linear resin formed by moving a nozzle that discharges a fluid resin along a toolpath, and in at least one of the plurality of single-layer structures, the toolpath is folded back at a turning point provided on the outer periphery of the toolpath, and comprises a folded portion located inside the toolpath from the outer periphery, wherein the folded portion is the portion between the end of the toolpath and the turning point. Preferably, the method described above, wherein the end portion overlaps the outer circumference. [Brief explanation of the drawing]
[0010] [Figure 1] This is a perspective view showing gyroid structure 1. [Figure 2] This is a perspective view showing the gyroid structure 1 in the process of being fabricated. [Figure 3] This is a perspective view showing the gyroid structure 1 in the process of being fabricated. [Figure 4] This is a perspective view showing the gyroid structure 1 in the process of being fabricated. [Figure 5] The toolpath 4 shown is used to form the single-layer structures 2 of each layer that make up the gyroid structure 1. [Figure 6] The toolpath 4 shown is used to form the single-layer structures 2 of each layer that make up the gyroid structure 1. [Figure 7] The toolpath 4 shown is used to form the single-layer structures 2 of each layer that make up the gyroid structure 1. [Figure 8] The toolpath 4 shown is used to form the single-layer structures 2 of each layer that make up the gyroid structure 1. [Figure 9] The toolpath 4 shown is used to form the single-layer structures 2 of each layer that make up the gyroid structure 1. [Figure 10] The toolpath 4 shown is used to form the single-layer structures 2 of each layer that make up the gyroid structure 1. [Figure 11] Figure 11A shows the state in which the single-layer structure 2 is stacked using toolpath 4 of the original data created with a build pitch of 0.1 mm, and Figure 11B shows the state in which the single-layer structure 2 is stacked using toolpath 4 selected such that the gap between layers in the original data becomes smaller in areas where the shape change of toolpath 4 between upper and lower layers in the original data is large. [Figure 12] Figure 12A shows a toolpath 4 with end 4a located on the outer periphery 4e, and Figure 12B shows a single-layer structure 2 with end 2a located on the outer periphery 2e. [Figure 13] Figure 12A shows the toolpath 4 with the folded portion 4d provided, and Figure 12B shows the single-layer structure 2 with the folded portion 2d provided.
Embodiments for Carrying out the Invention
[0011] Hereinafter, embodiments of the present invention will be described. Various characteristic matters shown in the embodiments described below can be combined with each other. Also, an invention can be established independently for each characteristic.
[0012] Hereinafter, the case where the base structure is a gyroide structure will be described as an example.
[0013] 1. Shaped object 5 The shaped object 5 (shown in FIG. 11B) of an embodiment of the present invention has a pseudo-gyroide structure described later, and has excellent isotropic deformability (no difference in the ease of deformation with respect to loads from any direction) compared to the shaped objects disclosed in Patent Document 1. Examples of the use of the shaped object 5 include a cushioning material (particularly, a cushioning material used for applications that touch the body, such as the part corresponding to the insole or the leg of a prosthetic limb). Hereinafter, the manufacturing method of the shaped object 5 of the present embodiment will be described step by step.
[0014] 2. Gyroide structure First, the gyroide structure related to the present invention will be described. As shown in FIG. 1, the gyroide structure 1 is a structure provided with a thickness based on a gyroide. A gyroide is a three-dimensional periodic minimal surface infinitely connected in three directions. The approximate formula of a gyroide can be expressed as in Formula 1 using trigonometric functions. Since a gyroide is composed of surfaces that meander in each of the XYZ directions, the gyroide structure is excellent in isotropic deformability.
Equation
[0015] 3. Layered manufacturing of the gyroide structure When forming a gyroid structure by additive manufacturing, first, printing data is created that includes toolpaths for forming each of the multiple single-layer structures 2 obtained by slicing the gyroid structure in the Z direction at a predetermined printing pitch. The multiple single-layer structures 2 are stacked in the Z direction. A toolpath is two-dimensional data that shows the path the nozzle moves when forming the single-layer structures 2, and it extends on the XY plane. The printing data is data that includes information necessary for printing, such as the toolpath and printing pitch for each layer of the object to be printed. A single-layer structure 2 can be formed by extruding a fluid resin (hereinafter, "fluid resin") from a nozzle, moving the nozzle along the toolpath to shape the fluid resin, and then solidifying the fluid resin. If the additive manufacturing is done using fused deposition modeling (FDM), the fluid resin is in a state of softened resin due to heating; if the additive manufacturing is done using UV curing, it is an uncured resin. In the former case, the fluid resin is solidified by cooling; in the latter case, the fluid resin is solidified by UV irradiation.
[0016] To form a layered structure, first, as shown in the first layer of Figure 2, a single-layer structure 201 of the first layer is formed by moving the nozzle while extruding the fluid resin along the toolpath of the first layer on a build table (not shown).
[0017] Next, after raising the nozzle by the build pitch, the second layer of single-layer structure 202 is formed by moving the nozzle along the toolpath of the second layer while extruding molten resin onto the first layer of single-layer structure 201. The single-layer structures 201 and 202 are fused together to obtain the laminated structure 302. Note that the nozzle only needs to be raised relative to the build table, and instead of raising the nozzle, the build table may be lowered.
[0018] Next, after raising the nozzle by the build pitch, the molten resin is extruded along the toolpath of the third layer while moving the nozzle over the layered structure 302 up to the second layer, thereby forming the third single-layer structure 203. The single-layer structure 203 is fused to the layered structure 302, and the layered structure 303 up to the third layer is obtained. The state of each layer at the completion of the build process when the same process is repeated up to 30 layers is shown in Figures 2 to 4.
[0019] By repeating the above process up to the top layer in the fabrication data, a desired fabricated object having a gyroid structure 1 can be obtained.
[0020] 4. Analysis of gyroid structure Here, we will perform a detailed analysis of the gyroid structure. Referring to Figures 2 to 4, layers 1 to 4 and layers 16 to 22 have X-direction meandering sections 2x where the single-layer structure 2 meanders in the X direction. Layers having such single-layer structure 2 are called X-direction meandering layers. Layers 7 to 13 and layers 25 to 30 have Y-direction meandering sections 2y where the single-layer structure 2 meanders in the Y direction. Layers having such single-layer structure 2 are called Y-direction meandering layers. Layers 5 to 6, layers 14 to 15, and layers 23 to 24 have connecting sections 2c where the X-direction meandering section and the Y-direction meandering section are joined. Layers having such single-layer structure 2 are called connecting layers. Thus, the gyroid structure is composed of X-direction meandering layers and Y-direction meandering layers that are formed alternately with connecting layers in between.
[0021] 5. Interlayer delamination problems caused by changes in the fabrication pitch of gyroid structures. To mass-produce objects with gyroid structures, it is necessary to increase the printing speed. One way to increase the printing speed is to increase the printing pitch of the gyroid structure. One way to increase the printing pitch of the gyroid structure is, for example, in the examples in Figures 2 to 4, to print in the order of layer 1, layer 4, layer 7, layer 10, layer 13, layer 16, etc., skipping two layers. In this case, a toolpath for forming single-layer structures of these layers is used, the printing pitch is tripled, and the amount of fluid resin extruded is also increased in accordance with the increase in printing pitch. In this case, the number of layers required for printing is reduced to one-third, so the printing time is shortened.
[0022] When fabrication is performed using this method, a single-layer structure 2 is formed on top of a single-layer structure 2 formed along the toolpath of the fourth layer, while another single-layer structure 2 is formed along the toolpath of the seventh layer. However, the shapes of the single-layer structures 2 of the fourth and seventh layers are significantly different, resulting in little overlap when viewed from the layering direction (Z-axis direction), and resulting in almost point contact. Therefore, when a gyroid structure is formed with such a fabrication pitch, the bonding between the single-layer structures 2 becomes weak at the points where the X-direction meandering layer and the Y-direction meandering layer switch, such as between the fourth and seventh layers, making delamination between layers more likely. In other words, simply increasing the fabrication pitch shortens the fabrication time, but it creates a new problem: the fabrication of the printed object becomes more prone to delamination between layers.
[0023] 6. Solutions to the delamination problem in gyroid structures The inventors of the present invention conducted diligent research to solve the above problem and discovered that even when fabrication is performed by skipping two layers, the shapes of the single-layer structure 2 (i.e., the shape of the toolpath) are similar for layers that meander in the X direction, such as the 1st and 4th layers, or the 7th and 10th layers, and the overlap when viewed from the layering direction (Z direction) is large. Therefore, no particular problems arise even if the 4th layer is formed on the 1st layer by skipping the 2nd and 3rd layers, or the 10th layer is formed on the 7th layer by skipping the 8th and 9th layers.
[0024] Based on these findings, when creating the fabrication data for fabricating the fabricated object 5 of this embodiment by selecting a portion of the toolpaths from the original data, which includes toolpaths for forming each of the multiple single-layer structures obtained by slicing the gyroid structure at a predetermined fabrication pitch, we came up with the idea to select the toolpaths in such a way that the gap between layers in the original data becomes smaller in areas where the shape change of the toolpath between upper and lower layers in the original data is large.
[0025] In the examples in Figures 2 to 4, in areas where X-direction meandering layers are continuous, such as layers 1 to 4 and layers 16 to 22, and in areas where Y-direction meandering layers are continuous, such as layers 7 to 13 and layers 25 to 30, the overlap of single-layer structures between upper and lower layers is large (i.e., the change in toolpath shape is small), whereas in areas where X-direction meandering layers and Y-direction meandering layers switch, such as layers 4 to 7 and layers 13 to 16, the overlap of single-layer structures between upper and lower layers is small (i.e., the change in toolpath shape is large). In such examples, for instance, when creating the printing data for printing object 5, toolpaths corresponding to the single-layer structures of layer 1, layers 4 to 7, layer 10, layers 13 to 16, layer 19, layers 22 to 25, and layer 28 are selected. In this selection method, all layers are selected at the point where the X-direction meandering layer and the Y-direction meandering layer switch (hereinafter referred to as the "switching point"), whereas in the point where the X-direction meandering layer or the Y-direction meandering layer is continuous (hereinafter referred to as the "continuous point"), layers are selected by skipping two layers.
[0026] With this method, at the transition points, for example, the shape of the single-layer structure changes gradually, such as between the 4th, 5th, 6th, and 7th layers. This increases the overlap of the single-layer structures between the upper and lower layers, thus suppressing the occurrence of delamination in the fabricated object 5. On the other hand, in the continuous sections, layers are selected by skipping two layers, which increases the fabrication speed.
[0027] The fabricated object 5, fabricated using such fabrication data, is provided with a structure in which the height of the continuous portion is relatively reduced compared to the height of the switching portion (hereinafter referred to as the "pseudo-gyroid structure"). Since the pseudo-gyroid structure is a structure based on the gyroid structure with the height of the continuous portion reduced, it retains the characteristics of the gyroid structure to some extent. For this reason, according to the present invention, a fabricated object 5 with superior isotropic deformability can be obtained compared to fabricated objects such as those disclosed in Patent Document 1.
[0028] Furthermore, when selecting layers at transition points and continuity points, the number of layers skipped during selection (i.e., the interval between layers in the original data) should be such that transition point < continuity point. Therefore, for example, layers may be selected by skipping one layer at transition points and layers by skipping two layers at continuity points.
[0029] As described above, in areas where the shape change of the toolpath between the upper and lower layers in the original data is large, a toolpath is selected such that the gap between layers in the original data becomes smaller, and by using the resulting molding data to form the molded object 5, a molded object 5 having a pseudo-gyroid structure is obtained that is less prone to delamination and allows for increased molding speed.
[0030] 7. Manufacturing method of the molded object according to this embodiment The fabricated object 5 of this embodiment can be obtained by performing additive manufacturing using the fabrication data created by the method described above. Additive manufacturing can be performed by stacking single-layer structures 2 formed according to the toolpath of each layer, as described in detail in "3. Additive Manufacturing of Gyroid Structures". Additive manufacturing may be performed by any method such as UV curing or fused deposition modeling, but fused deposition modeling, which involves stacking resin melted by heat, is preferred.
[0031] The diameter of the linear resin constituting the single-layer structure 2 (hereinafter referred to as "linear resin") and the molding pitch during molding are, for example, 0.3 to 6.0 mm, and preferably 1.0 to 4.0 mm. Specifically, this diameter is, for example, 0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, and 6.0 mm, and may be within the range of any two of the values exemplified here. The diameter of the linear resin is preferably larger than the molding pitch, and the value of [diameter of linear resin / molding pitch] is, for example, 1.1 to 6, specifically, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, and 6.0, and may be within the range of any two of the values exemplified here.
[0032] The resin constituting the molded object 5 is not particularly limited and includes ABS, polyolefin (e.g., polypropylene), polyester, and thermoplastic elastomer. If the molded object 5 requires high flexibility, such as a cushioning material, the resin constituting the molded object 5 is preferably a thermoplastic elastomer.
[0033] Examples of thermoplastic elastomers include styrene-based elastomers, olefin-based elastomers, and acrylic-based elastomers. It is preferable that this thermoplastic elastomer contains a styrene-based elastomer. Since styrene-based elastomers are highly flexible, the inclusion of a styrene-based elastomer in the thermoplastic elastomer increases its flexibility. The proportion of styrene-based elastomer in the thermoplastic elastomer is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, specifically, for example, 50, 60, 70, 80, 90, and 100% by mass, and may be within the range of any two of the values exemplified here.
[0034] Styrene-based elastomers are thermoplastic elastomers having styrene units, and examples include blends of one or more selected from styrene copolymers (e.g., styrene-ethylene-styrene block copolymer (SES), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene rubber (SBR), etc.) and hydrogenated styrene copolymers (e.g., styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-butylene-butadiene-styrene block copolymer (SBBS), hydrogenated styrene-butadiene rubber (HSBR), etc.).
[0035] The Shore A hardness of the thermoplastic elastomer is preferably between 0 and 10, specifically, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10, and may also be within the range of any two of the values exemplified here. When the Shore A hardness is within this range, a molded object 5 with excellent flexibility can be obtained. The Shore A hardness is measured according to JIS K6253.
[0036] 8. Structure of the 5th object The fabricated object 5 has a three-dimensional network structure composed of a pseudo-gyroid structure. With a fabricated object 5 having such a structure, the rigidity of the fabricated object 5 can be changed by changing the size of the pseudo-gyroid structure or by changing the thickness of the linear resin that makes up the single-layer structure. If the fabricated object 5 is a cushioning material, it is necessary to make the fabricated object 5 have the rigidity required by the user, and with a fabricated object 5 having a three-dimensional network structure, it is easy to fulfill such requirements.
[0037] 9. Specific examples of toolpath selection and manufacturing of objects using the selected toolpath. Here, we will explain a specific example of toolpath selection using more concrete data. Figures 5 to 10 show 60 toolpaths 4 for forming each of the multiple single-layer structures obtained by slicing the gyroid structure 1 with a molding pitch of 0.1 mm. In Figures 5 to 10, the left-right direction is the X direction, and the up-down direction is the Y direction. In the following explanation, the X-direction meandering portion 4x and the Y-direction meandering portion 4y of toolpath 4 correspond to the X-direction meandering portion 2x and the Y-direction meandering portion 2y of the single-layer structure 2, respectively. Also, since the linear resin 2b formed along toolpath 4 has a certain thickness, when a single-layer structure is formed along a toolpath that has a small distance between adjacent X-direction meandering portions 4x or adjacent Y-direction meandering portions 4y, such as the 6th to 7th layers, adjacent X-direction meandering portions 2x or adjacent Y-direction meandering portions 2y connect to form a joint portion 2c.
[0038] The toolpath 4 of the first to sixth layers has multiple Y-direction meandering sections 4y that meander in the Y direction. In the first to third layers, the multiple Y-direction meandering sections 4y extend generally parallel to each other, and the change in toolpath shape between upper and lower layers is small. In the fourth to sixth layers, the shape of the toolpath 4 changes so that adjacent Y-direction meandering sections 4y move closer to each other, and in the sixth layer, the distance between adjacent Y-direction meandering sections 4y is minimized.
[0039] The toolpath 4 for layers 7 to 30 has multiple X-direction meandering sections 4x that meander in the X direction. When moving from layer 6 to layer 7, the direction in which the meandering sections extend changes from the Y direction to the X direction. In layers 7 to 9, the shape of the toolpath 4 changes so that adjacent X-direction meandering sections 4x move away from each other, and in layers 10 to 27, the multiple X-direction meandering sections 4x extend roughly parallel to each other, with little change in the shape of the toolpath between upper and lower layers. In layers 28 to 30, the shape of the toolpath 4 changes so that adjacent X-direction meandering sections 4x move closer to each other, and in layer 30, the distance between adjacent X-direction meandering sections 4x is minimized.
[0040] The toolpath 4 for layers 31 to 53 has multiple Y-direction meandering sections 4y that meander in the Y direction. When moving from layer 30 to layer 31, the direction in which the meandering sections extend changes from the X direction to the Y direction. In layers 31 to 33, the shape of the toolpath 4 changes so that adjacent Y-direction meandering sections 4y move away from each other, and in layers 34 to 50, the multiple Y-direction meandering sections 4y extend roughly parallel to each other, with little change in the shape of the toolpath between upper and lower layers. In layers 51 to 53, the shape of the toolpath 4 changes so that adjacent Y-direction meandering sections 4y move closer to each other, and in layer 53, the distance between adjacent Y-direction meandering sections 4y is minimized.
[0041] The toolpath 4 for layers 54 to 60 has multiple X-direction meandering sections 4x that meander in the X direction. When moving from layer 53 to layer 54, the direction in which the meandering sections extend changes from the Y direction to the X direction. In layers 54 to 56, the shape of the toolpath 4 changes so that adjacent X-direction meandering sections 4x move away from each other, and in layers 57 to 60, the multiple X-direction meandering sections 4x extend roughly parallel to each other, resulting in a small change in the shape of the toolpath between upper and lower layers.
[0042] Thus, in the layers where the direction of the meandering section of toolpath 4 switches between the X and Y directions, and in the adjacent layers (layers 4-9, 28-33, and 51-56), the shape of toolpath 4 changes very significantly between upper and lower layers. This group of layers is called the "large change layer group." In the layers in between (layers 1-3, 10-27, 34-50, and 57-60), the shape of toolpath 4 changes only slightly between upper and lower layers. This group of layers is called the "small change layer group."
[0043] By utilizing the characteristics of toolpath shape changes, it is possible to select toolpath 4 such that the gap between layers in the original data becomes smaller in areas where the shape change of toolpath 4 between upper and lower layers in the original data (the original modeling data) is large.
[0044] In one example, in the large variation layer group, layers where the direction of the meandering section changes from the Y direction to the X direction (layers 6-7, 30-31, and 53-54), and layers skipped by one from these layers (layer spacing 1) are selected, while in the small variation layer group, three layers are selected at approximately equal intervals. With this selection method, for example, between layers 7 and 30, layers 7, 9, 28, and 30 are selected from the large variation layer group, and layers 14, 19, and 24 are selected from the small variation layer group. In the small variation layer group, the layer spacing is 3 or 4. This selection reduces the total number of layers to be fabricated from 24 to 7, significantly shortening the fabrication time.
[0045] Figure 11A shows a fabricated object obtained by stacking single-layer structures 2 at a printing pitch of 0.1 mm using toolpaths 4 for layers 7 to 30. Figures 11A and 11B show a cross-section of the linear resin 2a contained in the single-layer structure 2 at one point. The layers indicated by the bold circles in Figure 11A are the selected layers. Using the toolpaths 4 for these layers, the printing pitch and nozzle diameter were adjusted so that the height of the fabricated object was equal to the height in the original data, and printing data was created to obtain the fabricated object 5 of this embodiment. Using this printing data, additive manufacturing was performed to obtain the fabricated object 5 shown in Figure 11B. The 1st to 7th layers of the single-layer structure 2 contained in the fabricated object 5 correspond to the 7 layers (7th, 9th, 14th, 19th, 24th, 28th, and 30th layers) selected from the original data, respectively. Since the first to seventh layers are formed using the seven toolpaths 4 selected from the original data, their position and shape in the XY plane match those of the seven layers selected from the original data. On the other hand, because the diameter of the linear resin constituting the single-layer structure 2 has changed, the positions of the first to seventh layers in the Z direction (vertical direction in Figure 11) in Figure 11B are different from those of the seven layers selected from the original data, and the first to seventh layers are arranged at approximately equal intervals in the Z direction. In other words, the seven layers selected from the original data have inconsistent interlayer spacing, but the first to seventh layers in Figure 11B are formed with equal molding pitch.
[0046] The fabricated object 5 shown in Figure 11B has a shape similar to the fabricated object 5 created using the original data, even though additive manufacturing was performed using fabrication data with significantly fewer layers compared to the original data. Furthermore, it can be seen that in fabricated object 5, there is a large overlap of single-layer structures 2 between the upper and lower layers, resulting in a structure that is less prone to delamination. Thus, according to the present invention, fabricated objects can be manufactured with high accuracy in a relatively short time.
[0047] Note that the interlayer spacing between the large-change layer group and the small-change layer group, as well as the number of layers selected, may be set differently from those in the above embodiment.
[0048] 10. Modifying the toolpath Figure 12A shows an example of a toolpath 4 for manufacturing a molded object 5. This toolpath 4 has a pair of ends 4a. As shown in Figure 12B, a single-layer structure 2 can be formed by moving a nozzle that extrudes fluid resin along the toolpath 4 between the pair of ends 4a, thereby shaping linear resin 2b.
[0049] The end portion 4a is provided on the outer periphery 4e of the toolpath 4, and when a single-layer structure 2 is formed using such a toolpath 4, the end portion 2a of the linear resin 2b is provided on the outer periphery 2e of the single-layer structure 2. When the end portion 2a is provided on the outer periphery 2e of the single-layer structure 2, in a molded object 5 composed of multiple single-layer structures 2 stacked on top of each other, delamination of the molded object 5 is likely to occur starting from the end portion 2a. The end portion 2a may or may not be connected to the end portion of the upper or lower layer. If the end portion 2a is not connected to either the end portion of the upper or lower layer, the strength of the end portion 2a becomes particularly weak, highlighting the significant technical importance of applying the present invention.
[0050] Figure 13A shows a modified toolpath 4 to solve these problems. The toolpath 4 in Figure 13A is folded back at a turning point 4f provided on the outer circumference 4e of the toolpath 4, and includes a folded portion 4d located inside the toolpath 4 from the outer circumference 4e. The folded portion 4d is the part between the end 4a of the toolpath 4 and the turning point 4f. Preferably, the end 4a overlaps with the outer circumference 4e.
[0051] Figure 13B shows a single-layer structure 2 composed of linear resin 2b formed by moving a nozzle that discharges fluid resin along the toolpath 4 shown in Figure 13A. The linear resin 2b constituting the single-layer structure 2 is folded back at a folding point 2f provided on the outer periphery 2e of the single-layer structure 2, and includes a folded portion 2d located inside the single-layer structure 2 beyond the outer periphery 2e. The folded portion 2d is the part between the end 2a of the linear resin 2b and the folding point 2f.
[0052] With this configuration, the end portion 2a of the single-layer structure 2 is not exposed to the outer surface of the molded object 5, thus suppressing the occurrence of delamination from the end portion 2a of the single-layer structure 2. Preferably, the end portion 2a is welded to the outer peripheral portion 2e. In this case, the strength of the end portion 2a is further increased, and delamination of the molded object 5 is further suppressed.
[0053] The structure with folded-over portions 2d and 4d only needs to be provided in at least one of the multiple single-layer structures 2 that make up the molded object 5, but it is preferable to provide folded-over portions 2d and 4d in all layers where the ends 2a and 4a are located on the outer periphery 2e and 4e.
[0054] 11. Other Embodiments In the above embodiment, the case where the base structure is a gyroid structure was used as an example for explanation. However, even if the base structure has a complex shape other than a gyroid structure, the effect of being able to fabricate the fabricated part with high accuracy in a relatively short time is achieved, so the application of the present invention is not limited to gyroid structures. Examples of base structures include gyroid structures, Schwartz P structures, Schwartz D structures, double gyroid structures, fddd structures, and other structures in which a thickness is provided on a three-dimensional periodic minimum surface, as well as cubic structures, octet structures, and cubic octet structures. In the case where the base structure is a structure in which a thickness is provided on a three-dimensional periodic minimum surface, there are parts where the shape change of the toolpath between the upper and lower layers is particularly large, so the technical significance of applying the present invention is remarkable.
[0055] Furthermore, the content described in "10. Modifying Toolpaths" is also applicable to toolpath 4 included in the modeling data for creating objects of any structure. Therefore, the content described in "10. Modifying Toolpaths" is not particularly limited to the structure of the object. [Explanation of Symbols]
[0056] 1: Gyroid structure 2: Single-layer structure 2a: End 2b: Linear resin 2c: Joining part 2d: Folded part 2e: Outer periphery 2f: Turning point 2x: X-direction meandering section 2y: Y-direction meandering section 4: Toolpath 4a: End 4d: Folded part 4e: Outer periphery 4f: Turning point 4x: X-direction meandering section 4y: Y-direction meandering section 5: Modeled object 201: Single-layer structure 202: Single-layer structure 203: Single-layer structure 302: Laminated Structure 303: Laminated Structure
Claims
1. A structure composed of multiple single-layer structures stacked on top of each other, Each of the aforementioned multiple single-layer structures is constructed by forming a linear resin, A molded object in which, at both ends of the linear resin of the plurality of single-layer structures, the linear resin is folded back at a folding point provided on the outer periphery of the single-layer structure, and the folded portion is located inside the single-layer structure beyond the outer periphery, and the folded portion is the part between the end of the linear resin and the folding point.
2. The molded object according to claim 1, The end portion is welded to the outer circumference of the molded object.
3. The molded object according to Claim 2, The end portion is welded to the outer circumference at a position other than the folding point of the molded object.
4. A molded object according to any one of Claims 1 to 3, A molded object in which, at both ends of all the linear resins of the plurality of single-layer structures, the linear resins are folded back at a folding point provided on the outer periphery, and the folded portion is positioned inside the single-layer structure beyond the outer periphery.
5. A method for manufacturing a molded object composed of multiple single-layer structures stacked on top of each other, The aforementioned single-layer structure is composed of linear resin formed by moving a nozzle that discharges fluid resin along a toolpath, A method wherein, at both ends of the toolpath of the plurality of single-layer structures, the toolpath is folded back at a turning point provided on the outer periphery of the toolpath, and comprises a folded portion located inside the toolpath from the outer periphery, wherein the folded portion is the portion between the end of the toolpath and the turning point.
6. The method according to claim 5, The end portion is located on the path of the outer periphery.
7. The method according to claim 6, The end portion is located on the path of the outer periphery at a position other than the turning point.
8. A method according to any one of Claims 5 to 7, A method comprising the following steps, wherein at both ends of all the toolpaths of the plurality of single-layer structures, the toolpath is folded back at a folding point provided on the outer periphery, and comprises a folded portion located inside the toolpath from the outer periphery.