Three-dimensional modeling method, three-dimensional modeling device, and three-dimensional modeled object

Abstract

To provide a three-dimensional modeling method, a three-dimensional modeling device, and a three-dimensional modeled object, which can easily perform modeling of a three-dimensional modeled object that has been lightened as required.SOLUTION: There is provided a three-dimensional modeling method for forming a three-dimensional modeled object 101 by using a core material 116 containing a resin that hardens through a predetermined process, comprising: a core material injection process for injecting the core material 116, before the predetermined process is performed, into a frame body 125 corresponding to a shape of the three-dimensional modeled object 101; a lightweight member injection process for injecting a lightweight member 216, having a smaller specific gravity than the core material 116, into the core material 116 in the frame body 125; and a hardening step of hardening the core material 116 in the frame body 125 by carrying out the predetermined process.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a three-dimensional modeling method and apparatus for forming a three-dimensional object using additive manufacturing techniques such as 3D printing, and the three-dimensional modeling object. [Background technology]

[0002] The term 3D printer is widely used as the name of manufacturing equipment that uses 3D printing technology. A 3D printer is a three-dimensional modeling device that calculates the cross-sectional shape of a model using a computer based on 3D CAD data, divides the model into thin, round cross-sectional components, forms the cross-sectional components using various methods, and stacks them to form the desired model. Internationally, 3D printing technology is often used as a synonym for Additive Manufacturing Technology, and the Japanese translation is additive manufacturing technology.

[0003] In recent years, metal 3D printers and composite 3D printers have been attracting attention as they are now required to have rigidity and strength in addition to appearance for the purpose of evaluating actual products before mass production. In particular, in the three-dimensional modeling method disclosed in Patent Document 1 below, after the formation of shell layers and the filling of core material are repeated multiple times in a modeling tank, the core material is cured all at once by irradiating with active energy rays or applying thermal energy, and therefore, since there is no layer interface in the model formed by the core material, it is possible to form a model with no directional rigidity or strength. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-136923 A Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, there are cases where a reduction in weight is desired for the three-dimensional object produced by the above process, even if the physical properties such as strength are somewhat lower. One method for responding to such a demand is, for example, to form the core material filled in the shell layer so as to have a so-called hollowed-out shape, thereby reducing the weight by providing hollowed-out portions.

[0006] However, such a three-dimensional modeling method has problems in that the shape of the shell layer becomes complex, making modeling of the shell layer difficult, and the area for filling the core material becomes narrow, making filling of the core material difficult.

[0007] In view of the above problems, the present invention has an object to provide a three-dimensional modeling method, a three-dimensional modeling apparatus, and a three-dimensional model that can easily manufacture a three-dimensional model that is lightweight as needed. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the three-dimensional modeling method of the present invention is a three-dimensional modeling method for forming a three-dimensional object using a core material containing a resin that hardens through a predetermined process, and is characterized by having a core material injection process in which the core material is injected into a frame body corresponding to the shape of the three-dimensional object before the predetermined process is carried out, a lightweight member injection process in which a lightweight member having a smaller specific gravity than the core material is injected into the core material inside the frame body, and a hardening process in which the predetermined process is carried out and the core material inside the frame body is hardened.

[0009] This three-dimensional modeling method makes it possible to reduce the weight of a three-dimensional object by injecting a lightweight material without preparing a frame body of a complex shape.

[0010] In addition, the lightweight member after the hardening process has been carried out has a lower strength than the core material hardened by the hardening process, and in the lightweight member injection process, it is preferable to inject the lightweight member so that the lightweight member is concentrated and arranged at a predetermined location within the core material that forms the three-dimensional object.

[0011] By doing this, for example, by concentrating the lightweight members in parts of the three-dimensional object that do not require as much strength, it is possible to reduce the weight of the entire three-dimensional object while providing strength to the parts of the three-dimensional object that require it.

[0012] In addition, it is preferable that the core material injection step and the weight-reducing member injection step are performed alternately.

[0013] This allows the lightweight material to be injected into the core material at a time that is convenient for injection.

[0014] The weight-reducing member may be a structure made of the same material as the frame.

[0015] In this way, the means for forming the frame can also be used as the means for injecting the weight-reducing material, and the weight-reducing material can be easily provided within the core material.

[0016] In addition, in order to solve the above-mentioned problems, the three-dimensional modeling apparatus of the present invention is a three-dimensional modeling apparatus that forms a three-dimensional object using a core material containing a resin that hardens through a predetermined process, and is characterized by having a frame body placement unit that places a frame body according to the shape of the three-dimensional object, a core material injection unit that injects the core material before the predetermined process is carried out into the frame body placed in the frame body placement unit, a lightweight material injection unit that injects a lightweight material having a smaller specific gravity than the core material into the core material inside the frame body, and a hardening unit that carries out the predetermined process and hardens the core material inside the frame body.

[0017] This three-dimensional modeling apparatus can reduce the weight of a three-dimensional object by injecting a lightweight material without preparing a frame body of a complex shape.

[0018] In order to solve the above-mentioned problems, the three-dimensional object of the present invention is a three-dimensional object formed using a core material containing a resin that hardens through a specified process, and is characterized in that a lightweight material that has a lower specific gravity but lower strength than the hardened core material is mixed in the parts of the three-dimensional object that do not require relatively high strength, and the parts of the three-dimensional object that require relatively high strength are composed only of the hardened core material.

[0019] This three-dimensional object can be made lighter overall while providing strength to areas that require it. Effect of the Invention

[0020] The three-dimensional object fabrication method, the three-dimensional object fabrication apparatus, and the three-dimensional object fabricated according to the present invention can easily fabricate a three-dimensional object that has been made lighter as required. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a diagram illustrating a three-dimensional object forming apparatus according to an embodiment of the present invention. [Diagram 2] 1A to 1C are diagrams illustrating a three-dimensional object fabrication method according to an embodiment of the present invention. [Diagram 3] 1A to 1C are diagrams illustrating a three-dimensional object fabrication method according to an embodiment of the present invention. [Figure 4] 1A to 1C are diagrams illustrating a three-dimensional object fabrication method according to an embodiment of the present invention. [Diagram 5] 11A to 11C are diagrams illustrating a three-dimensional object fabrication method according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] As an embodiment of a three-dimensional modeling apparatus for carrying out the three-dimensional modeling method of the present invention, a three-dimensional modeling apparatus for filling a core material into a shell will be described with reference to FIG.

[0023] The three-dimensional modeling apparatus 100, which is a composite material 3D printer, has as its main components a modeling tank 111 in which a shell material 121, which is an ultraviolet curing resin, is stored, a laser optical system 112, a core material supply system 113, a lightweight member supply system 213, and a curing unit 140.

[0024] A shell material 121, which is a liquid phase material, is stored in the modeling tank 111, and the liquid surface position can be maintained and adjusted at a predetermined position by a shell material adjustment system (not shown). Well-known materials such as epoxy and acrylic shell materials can be used as the shell material 121. A modeling table 128 is provided in the modeling tank 111. The modeling table 128 is a base for supporting the three-dimensional object 101, and corresponds to the frame placement unit in this description. The modeling table 128 can be moved and set to any position in the Z-axis direction in the figure by a drive mechanism (not shown).

[0025] The laser optical system 112 consists of an ultraviolet laser light source 114 and a scanning optical system 115, and the ultraviolet laser light 130 emitted from the ultraviolet laser light source 114 can be scanned over a predetermined range on the liquid surface of the shell material 121 (i.e., the XY plane) by the scanning optical system 115.

[0026] The shell material 121 is hardened by irradiation with the ultraviolet laser light 130 to a predetermined depth from the liquid surface, as shown by the cured ultraviolet curing resin 123 in Fig. 1. This hardening depth is generally about 0.1 mm to 0.2 mm. Of course, this hardening depth can be adjusted by adjusting the output of the ultraviolet laser light source 114.

[0027] The top surface of the modeling table 128 is positioned at a depth that is approximately this hardening depth below the liquid surface of the shell material 121, and ultraviolet laser light 130 is irradiated to any position on the liquid surface of the shell material 121, thereby forming a hardened ultraviolet-curing resin 123 of any area on the modeling table 128.

[0028] After the cured ultraviolet curable resin 123 is formed on the modeling table 128, the modeling table 128 is lowered by the curing depth, and then ultraviolet laser light 130 is irradiated to any position on the liquid surface of the shell material 121, thereby stacking the cured ultraviolet curable resin 123 on the cured ultraviolet curable resin 123.

[0029] Then, by repeatedly lowering the modeling table 128 and irradiating the liquid surface of the shell material 121 with the ultraviolet laser light 130, the cured ultraviolet curable resin 123 is laminated, and a three-dimensional cured ultraviolet curable resin 123 can be obtained. In the present invention, the object thus formed is called a shell 125. This shell 125 is an outer shell layer for filling the core material 116 having a hollow shape, and the part surrounded by the shell 125 that has a bottom surface is called a core portion 126. The shell 125 obtained by curing the shell material 121 corresponds to the frame in this description, and by filling the core material 116 into this frame (core portion 126), a three-dimensional object having a desired shape can finally be obtained.

[0030] The core material supply system 113 transfers and supplies the core material 116, which is a liquid phase material, from a core material tank 117 that stores the core material 116 therein via piping systems 118b and 118a using a pump 119, and discharges it from the tip of a nozzle 120. The nozzle 120 can be moved and fixed in each of the X, Y and Z directions in the figure by a moving mechanism not shown. For this reason, the piping system 118a has a flexible structure and material so as to follow the movement of the nozzle 120.

[0031] Core material 116 is a thermosetting resin in which reinforcing materials such as carbon fibers are uniformly dispersed, and known thermosetting resins such as epoxy and acrylic resins can be used, as with shell material 121. Furthermore, core material 116 and shell material 121, which are liquid phase materials, have a higher density than air, which is a gas, and the specific gravity of core material 116 is greater than the specific gravity of shell material 121. In this embodiment, the ratio of the specific gravity of core material 116 to shell material 121 is approximately 1.25:1.1.

[0032] Core material 116 is filled into core portion 126 of shell 125, and heat energy is applied to core material 116 filled in core portion 126, whereby core material 116 is thermally cured. The thermally cured core material 116 and the shell 125 surrounding it are the three-dimensional object in this description, and a three-dimensional object of a desired shape can be obtained by filling core portion 126 having a desired shape with the core material and then thermally curing it. Furthermore, according to this method, since there is no layer interface in the three-dimensional object formed from core material 116, it is possible to form a three-dimensional object with no directional property in rigidity or strength.

[0033] The lightweight material supply system 213 transfers and supplies the lightweight material 216, which is a liquid phase material, from a lightweight material tank 217 storing the lightweight material 216 therein via piping systems 218b and 218a in order using a pump 219, and discharges it from the tip of a nozzle 220. The nozzle 220 can be moved and fixed in each of the X, Y and Z directions in the figure by a moving mechanism not shown. For this reason, the piping system 218a has a flexible structure and material so as to follow the movement of the nozzle 220.

[0034] Here, in this embodiment, the weight-reducing member 216 is a thermosetting resin that does not mix with the core material 116, and has a smaller specific gravity than the thermosetting resin contained in the core material 116. Note that, like the core material 116, the weight-reducing member 216 can be made of known thermosetting resins such as epoxy and acrylic resins.

[0035] The curing unit 140 is a means for curing the core material 116. In this embodiment, it is a heating furnace having a chamber capable of sealing a heating target (a shell 125 and the core material 116 filled therein, which will be described later in this embodiment, and a lightweight member 216) so as to heat the core material 116 containing a thermosetting resin to a temperature equal to or higher than the curing start temperature. Such a heating furnace is often disposed so as to be separated from the modeling tank 111, the laser optical system 112, the core material supply system 113, and the lightweight member supply system 213, but in this description, the three-dimensional modeling apparatus 100 will also include the curing unit 140.

[0036] Next, a three-dimensional object fabrication method according to an embodiment of the present invention will be described with reference to FIGS.

[0037] In the three-dimensional object fabrication method of the present invention, first, the three-dimensional object fabrication apparatus 100 fabricates the shell 125 and fills the core material 116 .

[0038] Specifically, first, in a state where the nozzle 120 is retracted from the irradiation range of the ultraviolet laser light 130, the ultraviolet laser light 130 is irradiated to an arbitrary position on the liquid surface of the shell material 121 on the modeling table 128, and the modeling table 128 is lowered by an amount corresponding to the hardening depth, alternately, thereby forming a shell 125 having a core portion 126 of a desired shape as shown in Fig. 2(a). Here, in this description, the process of modeling the shell 125 in this manner is referred to as a shell modeling process.

[0039] 2(b), the nozzle 120 moves into the core portion 126 formed in the shell 125, and the core material 116 is discharged from the nozzle 120 into the core portion 126, thereby progressing the filling of the core material 116. Here, in this description, the process of injecting the core material 116 into the core portion 126, which is the portion surrounded by the shell 125, is referred to as the core material injection process.

[0040] In this embodiment, the core material injection step is performed in a state where the shell 125 is immersed in the shell material 121 in the modeling tank 111, and the shell material 121 exists in the core portion 126 before the core material 116 is filled, as shown in Fig. 2(a). Then, as the core material 116, which has a larger specific gravity than the shell material 121, is filled, the shell material 121 is pushed up, and as shown in Fig. 2(b), the shell material 121 is pushed out of the shell 125 from the core portion 126 through an opening provided in the upper part of the shell 125. In other words, the shell material 121 is replaced with the core material 116.

[0041] The above-mentioned shell forming process and core material injection process may be performed alternately multiple times. That is, the shell 125 may be formed to a predetermined height, the core portion 126 formed by the shell 125 may be filled with the core material 116, the shell 125 may be expanded, and the core portion 126 formed by the expanded shell 125 may be injected with the core material 116. In this manner, even if the core portion 126 has a complex shape, the core material 116 can be filled in every corner of the core portion 126 by filling the core material 116 in stages.

[0042] 3(a), in the present invention, after the core material injection step, a weight-reducing member injection step is carried out, and the weight-reducing member 216 is injected into the required location in the core material 116. Specifically, the nozzle 220 moves to a predetermined location in the core material 116 filled in the core portion 126 by the core material injection step, and in this state, the weight-reducing member 216 is discharged from the nozzle 220, thereby replacing a part of the core material 116 with the weight-reducing member 216.

[0043] Here, since the core material 116 is made of resin, it has a relatively high viscosity (1000 to 1500 mPa s). Therefore, the weight-reducing members 216 injected into the core material 116 tend to remain in place without moving much. Therefore, it is possible to control the arrangement positions of the weight-reducing members 216 so that the weight-reducing members 216 are concentrated in a specific position in the core material 116 without dispersing the weight-reducing members 216 within the core material 116.

[0044] Furthermore, when the core material 116 is filled in stages as described above, it is preferable to carry out the lightweight member injection step immediately after the core material 116 is filled up to the position where the lightweight member 216 is to be placed. Then, after the lightweight member 216 is injected, it is preferable to carry out the next stage of the core material injection step as shown in FIG. 3(b). In this case, the core material injection step and the lightweight member injection step are carried out alternately. By doing so, it is possible to easily place the lightweight member 216 even in a position where it would be difficult to place the lightweight member 216 if the nozzle 220 were inserted and the lightweight member 216 was finally injected after the core material 116 corresponding to the entire three-dimensional object was filled.

[0045] The core material injection process and the lightweight material injection process are performed alternately until the shell 125 (frame body) is filled with an amount of core material 116 required to form the overall shape of the three-dimensional object. After that, the shell 125 filled with core material 116 is removed from the modeling table 128 of the three-dimensional modeling apparatus 100 and placed in the hardening section 140 as shown in FIG. 4(a).

[0046] Next, with the shell 125 and core material 116 placed in the hardening section 140, the inside of the hardening section 140 is heated to a temperature higher than the hardening start temperature of the core material 116. This starts hardening of the core material 116, and after a predetermined time (about 8 to 10 hours in this embodiment), the hardening of the entire core material 116 is completed, and the production of the three-dimensional object is completed at this point. During this process, the weight-reducing member 216, which is a thermosetting resin, is also hardened.

[0047] 4(b) shows the state when the hardening of the core material 116 is completed and the production of the three-dimensional object is completed. By hardening the core material 116 after the amount of core material 116 required to form the entire shape of the three-dimensional object has been filled, a three-dimensional object without a layer interface, as described above, is formed, in other words, a three-dimensional object in which the entire core material 116 is integrated, is formed. In this explanation, the hardened core material 116 and the shell surrounding it are collectively referred to as the three-dimensional object 101, and the process of hardening the core material 116 to produce the three-dimensional object 101 is referred to as the hardening process in this explanation.

[0048] Here, as described above, the weight-reducing member 216 is placed at a predetermined location in the core material 116 that is hardened in the hardening step, and the position of this weight-reducing member 216 in the core material 116 remains at that position without moving even during the hardening of the core material 116. Therefore, by controlling the position of the weight-reducing member 216 in the weight-reducing member injection step, it is possible to place the weight-reducing member 216 at an intended position in the completed three-dimensional object 101, as shown in FIG. 4(b).

[0049] As described above, the weight-reducing member 216 has a smaller specific gravity than the thermosetting resin contained in the core material 116, and furthermore, unlike the core material 116, it does not contain carbon fiber as a reinforcing material. Therefore, the strength of the weight-reducing member 216 after the curing process is lower than the strength of the core material 116 after curing. On the other hand, the specific gravity of the weight-reducing member 216 is significantly smaller than that of the core material 116 since it does not contain any reinforcing material, and the portion of the three-dimensional object 101 into which the weight-reducing member 216 has been injected is in a lightened state.

[0050] Therefore, in this embodiment, in the stage of the weight-reducing material injection process, the weight-reducing material 216 is injected into the core material 116 that is filled in a position corresponding to a portion of the three-dimensional object 101 that does not require relatively high strength. As a result, the portion of the three-dimensional object 101 that requires relatively high strength is made up of only the core material 116 without the weight-reducing material 216, as shown in part a101a in Fig. 4(b), and the portion that does not require relatively high strength is made up of the weight-reducing material 216 mixed in with the core material 116, as shown in part b101b, thereby forming a three-dimensional object 101 that has been made lighter while providing strength to the necessary portions.

[0051] In the method of forming a partially lightweight three-dimensional object 101 in this manner, the present invention can be implemented by inserting a nozzle into the core material 116 before it hardens and injecting the lightweight member 216, which makes it possible to easily reduce the weight of the three-dimensional object since there is no need to prepare a frame body having a complex shape for forming a hollowed-out three-dimensional object. Also, in the present invention, the degree of weight reduction of the three-dimensional object 101 can be easily adjusted by adjusting the degree of injection of the lightweight member 216.

[0052] Next, a three-dimensional object fabrication method according to another embodiment of the present invention will be described with reference to FIG.

[0053] In this embodiment, a weight-reducing member 125a is formed using a shell material 121 which is the material of a shell 125 serving as a frame.

[0054] 5(a), while the formation of the shell 125 and the filling of the core material 116 are alternately performed, when the core material is filled up to the height where the weight-reducing member 125a is to be provided, the shell material 121 at the position where the weight-reducing member 125a is to be provided is irradiated with ultraviolet laser light 130. As a result, the weight-reducing member 125a, which is the solidified shell material 121, is formed.

[0055] Thereafter, by continuing the formation of the shell 125 and filling the core material 116, it is possible to form a structure, that is, a lightweight member 125a made of the shell material 121, arranged within the core material 116, as shown in FIG. 5(b).

[0056] As described above, the specific gravity of the shell material 121 is smaller than that of the core material 116, and by providing the weight-reducing member 125a within the core material 116, the weight of the three-dimensional object can be reduced as in the previous embodiment.

[0057] In addition, the strength of the weight-reducing member 125a made of the shell material 121 is low in bending rigidity and easily deformed compared to the thermoset core material 116. In other words, it is not easily broken. Therefore, by providing the weight-reducing member 125a in the three-dimensional object as in this embodiment, even if the three-dimensional object is subjected to an excessive force and breaks, it is possible to prevent fragments from scattering.

[0058] In this embodiment, the means for forming the shell 125, which is the frame body (i.e., the means for hardening the shell material 121), can also be used as the means for injecting the weight-reducing member 125a. Therefore, since there is no need to separately prepare a dedicated means for injecting the weight-reducing member, such as the weight-reducing member supply system 213 in the previous embodiment, the weight-reducing member 125a can be easily provided in the core material 116.

[0059] The above-described 3D modeling method, 3D modeling apparatus, and 3D modeled object can easily produce a 3D model that is lightweight as needed.

[0060] Here, the three-dimensional modeling method of the present invention is not limited to the above-described three-dimensional modeling apparatus and three-dimensional modeled object, and may be of other forms within the scope of the present invention. For example, in the above description, the thermoset core material 116, the weight-reducing member 216 contained therein, and the shell 125 surrounding the core material 116 are collectively called the three-dimensional model, but only the thermoset core material 116 and the weight-reducing member 216 contained therein may be called the three-dimensional model, and the shell 125 may be destroyed after the core material 116 is thermoset.

[0061] Moreover, the frame does not necessarily have to be made of the shell material 121 as explained above, but may be a metal mold or a wooden mold.

[0062] Furthermore, the method for hardening the core material 116 does not necessarily have to be thermal hardening, and it may be light hardening using ultraviolet light or the like.

[0063] Furthermore, the hardening method of the weight-reducing member 216 does not necessarily have to be the same as the hardening method of the core material 116. For example, the core material 116 may be heat-hardened and the weight-reducing member 216 may be light-hardened. In this case, the weight-reducing member 216 may be the shell material 121 that is also the member forming the frame.

[0064] Furthermore, the core material 116 may be hardened while the weight reducing member 216 may not be hardened in order to produce the three-dimensional object 101. In this case, the weight reducing member may be discharged from the nozzle 220 in a gel state, for example.

[0065] Additionally, the weight reducing member 216 may be a gas such as dry air or helium.

[0066] In addition, in the above description, the core material injection process and the lightweight member injection process are performed alternately, but this is not limited to the above. For example, after the core material 116 equivalent to the entire three-dimensional object is filled, the nozzle 220 may be inserted last and the lightweight member 216 may be injected into a predetermined location within the core material 116. [Explanation of symbols]

[0067] 100 Three-dimensional modeling equipment 101 Three-dimensional sculpture 101a part a 101b part b 111 Modeling tank 112 Laser Optical System 113 Core material supply system 114 Ultraviolet laser light source 115 Scanning Optical System 116 Core material 117 Core material tank 118a Piping system 118b Piping system 119 Pump 120 Nozzle 121 Shell material 123 Cured UV-curable resin 125 Shell 125a Lightweight materials 126 Core 128 Modeling stand 130 Ultraviolet laser light 140 Heating means 213 Lightweight material supply system 216 Lightweight Materials 217 Lightweight material tank 218a Piping System 218b Piping system 219 Pump 220 Nozzle

Claims

1. A three-dimensional modeling method for forming a three-dimensional object using a core material containing a resin that hardens through a predetermined process, a core material injection step of injecting the core material into a frame according to a shape of the three-dimensional object before the predetermined process is performed; a lightweight member injection step of injecting a lightweight member having a specific gravity smaller than that of the core material into the core material in the frame body; a hardening step of hardening the core material in the frame by carrying out the predetermined process; A three-dimensional object forming method comprising the steps of:

2. 2. The three-dimensional object fabrication method according to claim 1, characterized in that the strength of the lightweight member after the hardening process is lower than that of the core material hardened by the hardening process, and in the lightweight member injection process, the lightweight member is injected so as to be concentrated and arranged at a predetermined location within the core material that forms the three-dimensional object.

3. The three-dimensional object fabrication method according to claim 2 , wherein the core material injection step and the weight-reducing member injection step are performed alternately.

4. The three-dimensional object fabrication method according to claim 1 , wherein the lightweight member is a structure made of the same material as the frame.

5. A three-dimensional modeling apparatus that forms a three-dimensional object using a core material containing a resin that hardens through a predetermined process, a frame placement unit that places a frame according to a shape of the three-dimensional object; a core material injection section that injects the core material into the frame disposed in the frame placement section before the predetermined process is performed; a lightweight member injection section that injects a lightweight member having a specific gravity smaller than that of the core material into the core material in the frame body; a hardening unit that hardens the core material in the frame by carrying out the predetermined process after injecting the core material in an amount sufficient to form the overall shape of the three-dimensional object; A three-dimensional modeling apparatus comprising:

6. It is a three-dimensional object formed using a core material containing a resin that hardens through a specific process, A lightweight member having a lower specific gravity and a lower strength than the hardened core material is mixed in a portion of the three-dimensional object that does not require a relatively large strength, A three-dimensional object, wherein a portion of the three-dimensional object that requires a relatively large strength is composed only of the hardened core material.

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