KR20220011399A - Fabrication method of 3 dimensional structures of thin shell with triply periodic minimal surfaces without templates - Google Patents

Abstract

The present invention relates to a method for manufacturing a three-dimensional thin film porous structure in the form of TPMS and comprises: (a) a step of forming a frame to correspond to a geometric straight line group determined depending on the type of TPMS; (b) a step of forming a fluid thin film between the frames; and (c) a step of curing the fluid thin film; wherein the fluid thin film is formed in a TPMS-shaped curved surface by surface tension. According to the present invention, the frame corresponding to a straight line group determined depending on the type of TPMS is formed without the step of forming and removing a template, and the thin film is formed directly on the frame. Therefore, the process is simple, the cost and time are saved, and in particular, the possibility of environmental pollution occurring in the template removal process such as chemical etching can be minimized. In addition, the three-dimensional thin film porous structure manufactured according to the present invention can be implemented in an ideal TPMS shape, and the strength of the entire structure is improved by the reinforcement effect of the frame.

Description

A method of manufacturing a three-dimensional structure composed of a thin film with a minimum curved shape of three cycles without a template

The present invention relates to a method for manufacturing a three-dimensional structure composed of a thin film, and more particularly, to a method for manufacturing a three-dimensional thin film porous structure in which the thin film surface has a three-period minimum curved surface or a similar curved surface shape. In this case, the three-dimensional structure composed of the thin film is also called "Shelluar" or a three-dimensional thin film porous structure.

Recently, Seungcheol Han et al. introduced a three-dimensional thin-film porous structure composed of a thin film called “Shellular” (Seung Chul Han, Jeong Woo Lee, Kiju Kang, “A New Type of Low Density Material; Shellular”, Advanced Materials, Vol. 27, pp.5506-5511, 2015.), “Shellular” is known to be very light and high in strength because a certain unit cell is periodically repeated and composed of a thin film.

As an ideal form of the above "Shellular", the German mathematician H.A. TPMS (Triply Periodic Minimal Surface: 3-periodic minimum surface) discovered by Schwarz for the first time is known (Gesammelte Mathematische Abhandlungen, Springer). TPMS is a curved surface that has a constant mean curvature at all points on the curved surface. As shown in FIG. 4, various types of TPMS exist, of which P-surface and D-surface shown in the upper left of FIG. 4 are most representatively cited in the fields of chemistry and biology. Also, in TPMS with zero average curvature, the optimal ratio of internal and external spaces is the same at 1:1, but even if the volume ratio is different, if the average curvature is uniform, the curved surface of the minimum surface area for a given internal/external space ratio is It can be called TPMS because it is formed (reference: M. Maldovan and EL Thomas, "Periodic Materials and Interference Lithography, 2009 WILEY-VCH Verlag GmbH & Co. KGaA, ISBN: 978-3-527-31999-2). Since such TPMS has a uniform average curvature everywhere on the curved surface, when an external load is applied to the shellular manufactured in the TPMS type, the stress is not concentrated on any one part. It is reported that buckling does not occur (Reference: Seung Chul Han, Kiju Kang, "Another Stretching-Dominated Micro-Architectured Material, Shellular," Materials Today, Volume 31, Pages 31-38, 2019.) Fig. 5 shows the local buckling occurring at the connections between truss elements in such a three-dimensional truss-type thin-film porous structure (Reference: L. Valdevit, SW Godfrey, TA Schaedler, AJ Jacobsen, WB Carter, “Compressive strength of hollow microlattices: Experimental characterization, modeling, and optimal design," J. Materials Research, Vol. 28, pp. 2461-2473, 2013.)

On the other hand, since the conventional "shellular" is composed of a thin film, the following steps had to be performed in order to manufacture it. 1) A template (sacrificial structure) is manufactured with a polymer, etc., 2) a coating layer of a hard material other than the template is formed on the surface, 3) some surface of the coating layer is removed to expose the inner template, 4 ) The "Shellular" was finally manufactured by removing the template by heat or chemical method.

The present inventors have proposed a total of 7 inventions through prior patents or applications in relation to the method for manufacturing such "Shellular", and these prior inventions 2) except for step 1) as described below ~ 4) the steps are the same. Specifically, with respect to the method of manufacturing the template of step 1) in the prior inventions, the first method to form the template using 3D optical lithography is disclosed in Korean Patent No. 1341216, and the second method is a polymer bead. Forming a template by arranging , after arranging them in a certain pattern, is to form a template in Korean Patent No. 1612500, Korean Patent No. 1905483, Korean Patent Application No. 10-2019-0027715, Korean Patent Application No. 10-2019-0027716 and Republic of Korea It is disclosed in Patent Application No. 10-2019-0101784, and after weaving a wire in the form of a three-dimensional truss in a third way, impregnating it with resin to form a template is disclosed in Korean Patent No. 1699943, respectively. 1, 2, and 3 each show a template formation principle according to these three methods.

However, since all the conventional methods for manufacturing TPMS-type shellular involve the steps of first forming a template and removing the template at the end, as described above, the process is complicated, costly and time-consuming, and also chemical etching If the template is removed by such a method, the possibility of environmental pollution is also high.

Korean Patent No. 1341216 Korean Patent No. 1612500 Korean Patent No. 1699943 Korean Patent No. 1905483 Korean Patent Application No. 10-2019-0027715 Korean Patent Application No. 10-2019-0027716 Korean Patent Application No. 10-2019-0101784

- Seung Chul Han, Jeong Woo Lee, Kiju Kang, "A New Type of Low Density Material; Shellular", Advanced Materials, Vol.27, pp.5506-5511, 2015. - Gesammelte Mathematische Abhandlungen, Springer - M. Maldovan and E. L. Thomas, "Periodic Materials and Interference Lithography, 2009 WILEY-VCH Verlag GmbH & Co. KGaA, ISBN: 978-3-527-31999-2 - Seung Chul Han, Kiju Kang, "Another Stretching-Dominated Micro-Architectured Material, Shellular," Materials Today, Vol. 31, Pages 31-38, 2019. - L. Valdevit, S. W. Godfrey, T. A. Schaedler, A. J. Jacobsen, W. B. Carter, "Compressive strength of hollow microlattices: Experimental characterization, modeling, and optimal design," J. Materials Research, Vol. 28, pp. 2461-2473, 2013.

An object of the present invention is to provide a method for manufacturing a three-dimensional structure composed of a thin film in the form of TPMS without a template. Another object of the present invention is to provide a method for forming a skeleton involved in such a three-dimensional structure manufacturing method and a mechanical design used therefor.

In the process of continuing research on manufacturing a three-dimensional structure composed of a thin film in the form of TPMS without a template, the present inventors, in the prior known literature on the geometry of TPMS (EA Lord and AL Mackay, "Periodic minimal surfaces In the case of some TPMS such as P-surface, D-surface, H-surface, or Neovius-surface through Current Science Vol. 85, pp. 346-362, 2003.), it is uniquely determined according to the TPMS surface Paying attention to the existence of a plurality of virtual geometric straight line groups that become did it The gist of the present invention regarding the recognition of the above-described problems and solutions based thereon is the same as described in the claims as follows.

(참고) 원안대로 적용대상을 제한하지 않기 위해 위와 같이 용어를 기재하였으며, 용어의 의미는 상세한 설명에 보충 설명하였습니다.(1) forming a skeleton to correspond to a geometric straight line group determined according to the type of TPMS; forming a fluid thin film between the skeletons; and curing the fluid thin film, wherein the fluid thin film is formed into a TPMS-shaped curved surface by surface tension.

(Reference) In order not to limit the scope of application as in the original plan, the terms are described as above, and the meanings of the terms are supplemented in the detailed description.

(2) The three-dimensional thin film porous structure manufacturing method of the TPMS type of (1), characterized in that the formation of the pull-out is a 3D printing method.

(3) The TPMS type three-dimensional thin film porous structure manufacturing method of (1) above, characterized in that the formation of the skeleton is a method of joining the intersections after arranging wires.

(4) The TPMS type three-dimensional thin film porous structure manufacturing method of (1) above, characterized in that the formation of the fluid thin film is an immersion method.

(5) The fluid thin film is a three-dimensional thin film porous structure manufacturing method of the TPMS type of (1), characterized in that any one of a thermoplastic resin, an ultraviolet curing resin, a thermosetting resin, a metal, or a ceramic.

(6) The curing process is a three-dimensional thin film porous structure manufacturing method in the form of (1) above, characterized in that the drying, exposure, heating, cooling is performed in any one method.

(7) The fluid thin film is formed of a polymer, and the polymer is converted into a ceramic by a curing process by thermal decomposition.

(8) The TPMS type three-dimensional thin film porous structure manufacturing method of (1) above, characterized in that the skeleton is alternately turned up and down according to a predetermined period in order to minimize the effect of gravity during the curing process of the fluid thin film.

(9) The TPMS is P-surface, D-surface, H-surface or Neovius-surface method for manufacturing a three-dimensional thin-film porous structure of the above (1), characterized in that any one.

According to the present invention, a skeleton corresponding to a straight line group determined according to the type of TPMS is formed without the step of forming and removing a template, which is essential in the conventional method for manufacturing a three-dimensional structure composed of a thin film of the TPMS type, and is directly attached to the skeleton. Since the thin film is formed, the process is simple, cost and time are saved, and in particular, the possibility of environmental pollution occurring in the template removal process such as chemical etching can be minimized. In addition, in the case of the three-dimensional thin film porous structure manufactured according to the present invention, since the curved surface of the thin film is precisely controlled by surface tension, it can be implemented in an ideal TPMS shape, and the skeleton constitutes a part of the final three-dimensional thin film porous structure. Since it exhibits a reinforcing effect, the strength of the overall structure is improved compared to the conventional three-dimensional thin film porous structure made of a single material.

A schematic diagram of a manufacturing process of a template for manufacturing a three-dimensional thin film porous structure according to the prior art of FIG. 1 .
Figure 4 is an example of a three-periodic minimal surface (TPMS; Triple Periodic Minimal Surface).
5 is a view showing a local buckling phenomenon in a three-dimensional truss-type thin film porous structure according to the prior art.
6 is a view for explaining the principle of forming a TPMS by surface tension when forming a fluid thin film on the skeleton according to the present invention.
7 is a view showing a straight line group determined according to a type of TPMS together with a unit cell according to an embodiment of the present invention.
8 is a view showing a straight line group determined according to a type of TPMS together with a plurality of unit cells according to an embodiment of the present invention.
9 is a view showing only the straight line group in FIG. 8 .
10 is a photograph of 3-D printing of a skeleton corresponding to a straight line group determined according to the type of TPMS according to an embodiment of the present invention.
11 is a photograph produced by arranging wires in a skeleton corresponding to a straight line group determined according to the type of TPMS according to an embodiment of the present invention and then joining the intersection points.
12 is a photograph of a fluid thin film formed on the skeleton of FIG. 10;
13 is a photograph of a fluid thin film formed on the skeleton of FIG. 11;

Hereinafter, the present invention will be described in detail through examples. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Accordingly, since the configuration of the embodiments described in this specification is only one of the most preferred embodiments of the present invention and does not represent all the technical spirit of the present invention, various equivalents that can be substituted for them at the time of filing of the present invention It should be understood that there may be variations and variations. On the other hand, in the drawings, the same or similar reference numbers are given to the same or equivalents, and in the entire specification, when it is said that a part "includes" a certain component, it is a different component unless specifically stated to the contrary. It does not exclude, but means that other components may be further included.

The three-dimensional structure composed of a thin film according to the present invention may be of a different type, but is implemented in the form of a three-period minimum curved surface or a form close to it, as in Korean Patent No. 1905483. In this case, the three-dimensional structure composed of a thin film (hereinafter, “three-dimensional thin film porous structure”) is a lightweight structure in which certain unit cells composed of a thin film are periodically repeated as in the above-described “shellular”.

A three-dimensional thin film porous structure manufacturing method according to the present invention comprises the steps of: forming a skeleton to correspond to a geometric straight line group determined according to the type of TPMS; forming a fluid thin film between the skeletons; and curing the fluid thin film, wherein the fluid thin film is formed into a TPMS-shaped curved surface by surface tension. In the present invention, the TPMS curved surface of the three-dimensional thin film porous structure is a principle that when a fluid thin film is formed in the space between the frameworks, the fluid thin film is naturally guided to the TPMS curved surface by surface tension.

First, the framework serves to form the basis or mediate the formation of a TPMS type thin film in the manufacturing process of the three-dimensional thin film porous structure, and also remains with the thin film in the final target, the three-dimensional thin film porous structure, to reinforce the overall rigidity of the structure. plays a role Such a skeleton corresponds to the curved shape of the three-dimensional thin film workable structure, that is, a straight line group related to TPMS.

In this case, the 'group of straight lines related to TPMS' is a 'group of straight lines determined according to the type of TPMS', and there is no commonly used name, but in the present specification, it means 'a virtual geometric element uniquely determined according to the TPMS curved surface'. used, and the curved profile of the TPMS can be defined or defined by this straight line group. Until now, this straight line group has been identified through the prior known literature on the geometry of TPMS (EA Lord and AL Mackay, "Periodic minimal surfaces of cubic symmetry," Current Science Vol. 85, pp. 346-362, 2003.) Its existence has been demonstrated in some TPMS such as P-surface, D-surface, H-surface or Neovius-surface. The curved profile of the three-dimensional thin film porous structure to which the present invention can be applied is premised on the existence of a straight line group having the same characteristics as the straight line group disclosed in the preceding document among the TPMS curved surface or a curved surface equivalent thereto, for this purpose The contents described in the preceding documents may be incorporated by reference as a part of the present invention.

6 is a photograph illustrating the principle of forming a TPMS by surface tension when forming a fluid thin film on a skeleton according to the present invention. Although the figure illustrates two types of a hexahedral type made of wire, a skeleton without four straight elements, and a skeleton with two circular rings arranged in parallel, the skeleton shown in FIG. 6 is a straight line related to the specific TPMS described above. It does not correspond to a group and is an example presented to simplify and explain the principle of forming a curved surface. When a soap film is formed as a kind of a fluid thin film between the skeletons for each of these two types of skeletons, the soap film is formed to have a minimum area by surface tension.

That is, if the skeleton for forming the soap film is not on a two-dimensional plane as shown in FIG. 6, the soap film formed in a three-dimensional space through it has a curved shape defined by principal curvatures in two directions. The average of the principal curvatures in these two directions is called the mean curvature for the corresponding surface. If this is a surface that has zero or a constant value and is periodically repeated in three directions in three-dimensional space, it is called a three-period minimum surface (TPMS). can do.

In this case, a curved surface that is periodically repeated in three directions in three-dimensional space is assumed to be expanded to have regularity in three directions in three-dimensional space, for example, by using the skeleton illustrated in FIG. 6 as one unit cell. It can be seen that it can be realized by forming a fluid thin film such as a soap film on the skeleton.

7 is a view exemplarily showing a straight line group determined according to the type of TPMS together with a unit cell of the corresponding TPMS according to an embodiment of the present invention. (Cubic Symmetry) P, D, H, and Neovius shows a group of straight lines existing in a unit cell of a curved surface. FIG. 8 is a view exemplarily showing a group of straight lines existing on a curved surface configured by connecting a plurality of unit cells of FIG. 7 together with a plurality of unit cells, and FIG. 9 is a view showing a plurality of unit cells and their It is a diagram showing only the straight line group by way of example except for the curved surface by

Therefore, as shown in FIG. 9, when a skeleton corresponding to a straight line group related to the TPMS curved surface of the three-dimensional thin film porous structure to be manufactured is formed, and a fluid thin film is formed based on this skeleton, the intended TPMS is naturally realized by surface tension, By curing the fluid thin film, it becomes possible to manufacture a three-dimensional thin film porous structure in the form of a solid TPMS in which the skeleton and the fluid thin film are integrated.

In this case, the skeleton is a kind of truss structure made of a wire or a rod, and the formation method thereof may be made in various ways. The material of the skeleton is not particularly limited, and may be selected from various materials such as resin, metal, or ceramic according to a method of fabricating the skeleton. In addition, the diameter of the wire or rod constituting the skeleton is not particularly limited and may be made as small as possible in order to realize a more ideal TPMS curved surface in consideration of the thin film thickness of the structure to be manufactured.

10 shows a photograph of 3-D printing of a skeleton corresponding to a straight line group determined according to the type of TPMS according to an embodiment of the present invention. Specifically, FIGS. 10(a) and 10(b) are examples of manufacturing skeletons corresponding to straight line groups on P and D curved surfaces, respectively, with a 3D printer. On the other hand, in the case of the skeleton for the P curved surface according to FIG. Based on the dotted line, it was cut from the bottom and manufactured to have a circular ring shape.

11 shows a photograph prepared by arranging wires in a skeleton corresponding to a straight line group determined according to the type of TPMS and then joining the intersection points according to another embodiment of the present invention. Specifically, FIGS. 11 (a) and (b) are examples of manufacturing a skeleton corresponding to a straight line group on P and D curved surfaces, respectively, with a small diameter metal wire, which is manufactured by a 3D printer according to the embodiment of FIG. Unlike the case, it is possible to manufacture in the form of maintaining the sharp triangular vertex on the outermost part of the skeleton for the P surface. In the case of the embodiment of FIG. 11, by using a wire of a small diameter as much as possible and fixing the intersection point of the wire by using an adhesive such as resin, or by bonding and fixing through welding, etc. Skeletons can be crafted.

The formation of the fluid thin film may be preferably carried out in a manner of simply immersing the skeleton in a fluid used as a thin film material. Specifically, in FIGS. 12 (a) and (b), stained glass paint, a type of thermoplastic resin, is formed as a fluid thin film on a skeleton manufactured by a 3D printer according to FIGS. 10 (a) and (b), respectively. Thus, an example in which P and D curved surfaces are formed is shown. Similarly, FIGS. 13(a) and 13(b) show examples in which stained glass paint is formed as a fluid thin film on a skeleton manufactured by bonding wires according to FIGS. 11(a) and (b), respectively. In the process of forming such a fluid thin film, a three-dimensional thin film porous structure composed of an ideal TPMS or a thin film close to it can be manufactured without any additional work other than immersing the skeleton in the liquid thermoplastic resin and taking it out. have. On the other hand, in some cases, when a fluid thin film is formed between unwanted skeletal elements after immersion, particularly between skeletal elements exposed to the outermost side, an operation of bursting and removing may be involved.

The curing process of the fluid thin film is a finishing operation to obtain a final three-dimensional thin porous structure by converting the liquid thin film into a solid phase. Heating, cooling, or a combination thereof may be performed in various ways. When the thermoplastic resin of FIGS. 12 and 13 is used, it may be cured by a simple drying method. In addition, in order to minimize the effect of gravity during the curing process of the fluid thin film, it may be advantageous to produce an ideal three-dimensional thin film porous structure in the form of an ideal TPMS to alternately invert the skeleton in the vertical direction according to a predetermined period.

The fluid thin film material is not particularly limited as long as it is a liquid fluid material having affinity with the material of the skeleton, that is, intermolecular force and surface tension. In consideration of the use of thin-film porous structures or manufacturing process conditions such as curing process, thermoplastic resin (e.g. paint) dissolved in solvent, UV-curable resin in monomer state, epoxy It may be variously selected from a thermosetting resin, such as a liquid metal or ceramic.

For example, when the fluid thin film material is a thermoplastic resin or UV-curable resin, after forming a film on the skeleton of a metal, polymer, or ceramic material, it is dried in the air at a certain temperature or exposed to UV rays to cure and further heat to high temperature. By doing so, higher strength can be obtained. When the fluid thin film material is a liquid metal, glass, or ceramic such as quartz, a solid thin film can be obtained by forming a film on the skeleton of a material that can withstand high temperatures and then cooling. In addition, in the case of a resin by mixing a curing agent or a solvent during curing, the viscosity increases over time during the film formation process, resulting in an excessively large film thickness or film formation inhibition. A constant viscosity can be maintained until initiation, which makes it relatively easy to control operating and process conditions.

, H. J. Kleebe, Eds., Polymer Derived Ceramics (DEStech Publications, Lancaster, PA, 2010), 이러한 열분해를 통하여 3차원 다공질 세라믹을 제작한 사례도 소개되고 있다 (참고문헌: A. J. Jacobsen, S. Mahoney, W. B. Carter, S. Nutt, "Vitreous carbon micro-lattice structures", Carbon Vol. 49, pp.1025-1032, 2011. Z. C. Eckel, C. Zhou, J. H. Martin, A. J. Jacobsen, W. B. Carter, T. A. Schaedler, "Additive manufacturing of polymer-derived ceramics," Science, Vol. 351, Issue 6268, pp.58-59, 2016.) 이와 같이 수지로 박막 재료로 하여 뼈대에 박막 구조체를 만든 후, 해당 수지 재질의 박막 구조체를 열분해하여 세라믹으로 변환하면 보다 높은 강도를 가지며 내열성을 갖는 세라믹 3차원 박막 구조체를 얻을 수 있다. 이 경우 본 발명의 박막 구조체는 매우 얇고 부드러운 TPMS 곡면 형태를 가지므로 열분해에 따른 부피수축 과정에서 발생하기 쉬운 균열을 억제하는데 유리하다. Meanwhile, in the curing process, the material of the final three-dimensional thin film porous structure may be determined by including the process of reforming the fluid film film into a heterogeneous material. For example, recently, a technology for converting a polymer into a ceramic by pyrolysis in a high-temperature environment in which oxygen is suppressed has been introduced (References: P. Colombo, R. Riedel, GD Sorar).

, HJ Kleebe, Eds., Polymer Derived Ceramics (DEStech Publications, Lancaster, PA, 2010), a case of producing a three-dimensional porous ceramic through such pyrolysis is also introduced (References: AJ Jacobsen, S. Mahoney, WB Carter , S. Nutt, “Vitreous carbon micro-lattice structures”, Carbon Vol. 49, pp.1025-1032, 2011. ZC Eckel, C. Zhou, JH Martin, AJ Jacobsen, WB Carter, TA Schaedler, “Additive manufacturing of Polymer-derived ceramics," Science, Vol. 351, Issue 6268, pp.58-59, 2016.) After making a thin film structure on the skeleton using resin as a thin film material, the thin film structure made of the resin material is pyrolyzed to produce ceramics. When converted to , a ceramic three-dimensional thin film structure having higher strength and heat resistance can be obtained. In this case, since the thin film structure of the present invention has a very thin and soft TPMS curved surface, it is advantageous in suppressing cracks that are likely to occur in the process of volume shrinkage due to thermal decomposition.

As described above, according to the present invention, a skeleton corresponding to a straight line group determined according to the type of TPMS is formed without the step of forming and removing the template, which is essential in the method of manufacturing a three-dimensional structure composed of a conventional TPMS type thin film, and the corresponding Since the thin film is formed directly on the skeleton, the process is simple, cost and time are saved, and in particular, the possibility of environmental pollution occurring in the template removal process such as chemical etching can be minimized. In addition, in the case of the three-dimensional thin film porous structure manufactured according to the present invention, since the curved surface of the thin film is precisely controlled by surface tension, it can be implemented in an ideal TPMS shape, and the skeleton constitutes a part of the final three-dimensional thin film porous structure. Since it exhibits a reinforcing effect, the strength of the overall structure is improved compared to the conventional three-dimensional thin film porous structure made of a single material.

The above description relates to specific embodiments of the present invention. As described above, the embodiments according to the present invention are disclosed for the purpose of explanation and are not to be construed as limiting the scope of the present invention, and those of ordinary skill in the art will not depart from the essence of the present invention. It should be understood that various changes and modifications are possible.

For example, in the embodiment of the present invention, some TPMS, that is, P-surface, D-surface, H-surface, or Neovius-surface has been described as an example, but it is not limited, and the existence of a straight line group that is the basis of skeletal formation is known in the prior art. It can be applied to all TPMS disclosed in the literature (EA Lord and AL Mackay, "Periodic minimal surfaces of cubic symmetry," Current Science Vol. 85, pp. 346-362, 2003.) as having a straight group. For reference, according to the literature, TPMS having such a straight line group may have cubic symmetry or not. Furthermore, even in other TPMS cases in which the existence of such a straight line group has not been confirmed through the preceding documents, etc. at the present time, if the existence of a straight line group having the same characteristics as that of the straight line group disclosed in the preceding document is confirmed, the present invention The disclosed manufacturing method can be applied in the same principle. Accordingly, all such modifications and variations can be understood to correspond to the scope of the invention disclosed in the claims or equivalents thereof.

Claims (9)

forming a skeleton to correspond to a geometric straight line group determined according to the type of TPMS; forming a fluid thin film between the skeletons; and curing the fluid thin film, wherein the fluid thin film is formed into a TPMS-shaped curved surface by surface tension.
[Claim 3] The method according to claim 1, wherein the strip is formed by a 3D printing method.
[Claim 3] The method according to claim 1, wherein the framework is formed by arranging wires and then joining the intersections.
The method according to claim 1, wherein the fluid thin film is formed by an immersion method.
The method of claim 1, wherein the fluid thin film is any one of a thermoplastic resin, an ultraviolet curing resin, a thermosetting resin, a metal, or a ceramic.
The method of claim 1, wherein the curing process is performed by any one of drying, exposure, heating, and cooling.
The method according to claim 1, wherein the fluid thin film is formed of a polymer, and the polymer is converted into a ceramic by a curing process by thermal decomposition.
The method according to claim 1, wherein in order to minimize the effect of gravity during the curing process of the fluid thin film, the skeleton is alternately turned up and down according to a predetermined period.
The method of claim 1, wherein the TPMS is any one of P-surface, D-surface, H-surface, and Neovius-surface.

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