Three-dimensional modeling method

Abstract

A three-dimensional modeling method comprises modeling a shell layer of a three-dimensional modeling object using a shell material, and modeling a core portion inside of the modeled shell layer using a core material. The modeling of the shell layer is performed by an additive manufacturing technology, and is divided into multiple steps in a lamination modeling direction of the three-dimensional modeling object. The modeling of the core portion includes filling the core material inside of the modeled shell layer subsequent to each modeling of the shell layer that has been divided into the multiple steps, and correctively curing the core material by irradiation with an active energy ray or by application of heat energy after the multiple steps of the modeling of the shell layer and the filing of the core material are all completed.

Claims

1. A three-dimensional modeling method comprising: modeling a shell layer of a three-dimensional modeling object using a shell material; and modeling a core portion inside of the shell layer using a core material, with the core material being curable from a fluid state to a non-fluid state by irradiation with an active energy ray or by application of heat energy, the modeling of the shell layer being performed by an additive manufacturing technology, and including repeatedly modeling each of multiple sections of the shell layer in a lamination modeling direction of the three-dimensional modeling object, the modeling of the core portion including repeatedly filling the core material inside of each of the multiple sections of the shell layer subsequent to each modeling of each of the multiple sections of the shell layer, and correctively curing the core material by the irradiation with the active energy ray or by the application of the heat energy after the modeling of the shell layer and the filling of the core material are all completed, the core material filled inside the shell layer maintaining a fluid state prior to the correctively curing of the core material, and the filling of the core material being performed by injecting the core material from a nozzle of a three-dimensional printer into a filled core material that has already been filled while a tip of the nozzle is being disposed in the filled core material.

2. The three-dimensional modeling method according to claim 1, wherein the shell layer is modeled by a vat polymerization, the shell material is curable from a fluid state to a non-fluid state by irradiation with an active energy ray, and an uncured part of the shell material inside of the shell layer is also cured by further irradiating with an active energy ray at the same time as or before and after the core material is collectively cured.

3. The three-dimensional modeling method according to claim 2, wherein when the core material is filled inside of the shell layer, an uncured part of the shell material and the core material are replaced with each other by injecting the core material.

4. The three-dimensional modeling method according to claim 1, wherein the shell material and/or the core material contains a reinforcing material.

5. The three-dimensional modeling method according to claim 4, wherein the reinforcing material is a fibrous reinforcing material made of carbon fiber, glass fiber, aramid fiber, or a combination thereof.

6. The three-dimensional modeling method according to claim 2, wherein the lamination modeling direction is a gravitational direction, and a specific gravity of an uncured core material is larger than a specific gravity of an uncured shell material.

7. The three-dimensional modeling method according to claim 2, wherein the shell material and/or the core material contains a reinforcing material.

8. The three-dimensional modeling method according to claim 3, wherein the shell material and/or the core material contains a reinforcing material.

9. The three-dimensional modeling method according to claim 7, wherein the reinforcing material is a fibrous reinforcing material made of carbon fiber, glass fiber, aramid fiber, or a combination thereof.

10. The three-dimensional modeling method according to claim 8, wherein the reinforcing material is a fibrous reinforcing material made of carbon fiber, glass fiber, aramid fiber, or a combination thereof.

11. The three-dimensional modeling method according to claim 3, wherein the lamination modeling direction is a gravitational direction, and a specific gravity of an uncured core material is larger than a specific gravity of the uncured shell material.

12. The three-dimensional modeling method according to claim 1, wherein the lamination modeling direction is a gravitational direction, and a specific gravity of an uncured core material is larger than a specific gravity of the uncured shell material.

13. The three-dimensional modeling method according to claim 4, wherein the lamination modeling direction is a gravitational direction, and a specific gravity of an uncured core material is larger than a specific gravity of an uncured shell material.

14. The three-dimensional modeling method according to claim 5, wherein the lamination modeling direction is a gravitational direction, and a specific gravity of an uncured core material is larger than a specific gravity of an uncured shell material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a figure showing a modeling object by a three-dimensional modeling method in accordance with the present invention.

(2) FIG. 2 is a figure showing a state during modeling of the modeling object by the three-dimensional modeling method in accordance with the present invention.

(3) FIG. 3 is a figure showing a state during modeling of the modeling object by the three-dimensional modeling method in accordance with the present invention.

(4) FIG. 4 is a figure showing a state during modeling of the modeling object by the three-dimensional modeling method in accordance with the present invention.

(5) FIG. 5 is a figure showing a state during modeling of the modeling object by the three-dimensional modeling method in accordance with the present invention.

(6) FIG. 6 is a figure showing a state during modeling of the modeling object by the three-dimensional modeling method in accordance with the present invention.

(7) FIG. 7 is a figure showing a state during modeling of the modeling object by the three-dimensional modeling method in accordance with the present invention.

(8) FIG. 8 is a figure showing a composite material 3D printer in accordance with another embodiment of the present invention.

(9) FIG. 9 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(10) FIG. 10 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(11) FIG. 11 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(12) FIG. 12 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(13) FIG. 13 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(14) FIG. 14 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(15) FIG. 15 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(16) FIG. 16 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(17) FIG. 17 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(18) FIG. 18 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(19) FIG. 19 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(20) FIG. 20 is a figure showing a state during modeling by the composite material 3D printer in accordance with the present invention.

(21) FIG. 21 is a figure showing modeling by a three-dimensional modeling apparatus in accordance with a prior art.

(22) FIGS. 22A, 22B, 22C, 22D and 22E are figures showing a three-dimensional modeling apparatus by a vat polymerization.

(23) FIG. 23 is a figure showing a three-dimensional modeling apparatus by a material extrusion.

(24) FIGS. 24A and 24B are figures showing a three-dimensional modeling apparatus by a powder bed fusion.

(25) FIG. 25 is a principle diagram of a directed energy deposition.

(26) FIGS. 26A, 26B and 26C are schematic diagrams showing a state in which a composite material is applied to a 3D printer by a material extrusion in accordance with a prior art.

(27) FIGS. 27A, 27B and 27C are schematic diagrams showing a state in which a composite material is applied to a three-dimensional modeling apparatus by a vat polymerization in accordance with a prior art.

DETAILED DESCRIPTION OF EMBODIMENTS

(28) First, the most basic embodiment of a three-dimensional modeling method according to the present invention will be conceptually described with reference to FIGS. 1 to 7. It should be noted that, in these drawings, the dimensions of the three-dimensional modeling object itself and a shell layer and a core portion thereof are exaggerated for easy understanding of the gist of the present invention.

(29) A three-dimensional modeling object 1 has a core portion 1b in a shell layer 1a, and a core material 2 is filled in the core portion 1b and solidified to form the final three-dimensional modeling object 1.

(30) First, as shown in FIG. 2, the shell layer 1a is modeled at an appropriate height h1. A modeling method and apparatus according to an additive manufacturing method can be used for modeling the shell layer 1a, and the height direction is preferably the lamination modeling direction in the additive manufacturing method.

(31) The core material 2 is filled when the shell layer is modeled by h1 (FIG. 3). The core material 2 is filled but not solidified, and subsequently the shell layer 1a is further modeled to a height of h2 as shown in FIG. 4. In this state, the core material 2 is further filled to obtain the state shown in FIG. 5.

(32) It should be noted here that one of the effects of the present invention is that when the core material 2 is additionally filled on the core material 2a that had already filled up to the height h1 shown in FIG. 4, which results in a state of FIG. 5, both the core material 2 and the filled core material 2a are in an uncured and liquid state having fluidity, and that even if the core material 2 is additionally filled on the core material 2a, both can be easily mixed with each other, and no interface (modeling interface) between the core material 2 and the filled core material 2a is formed at the height h1. Further, in the state of FIG. 5, it is possible to further promote the mixing of the two by stirring the core material 2 with an appropriate stirring member or the like (not shown).

(33) This makes it possible that when the core material is a composite material containing a reinforcing material, the problem of the separation of the reinforcing material or the dispersed state of the reinforcing material at the modeling interface, which is mentioned as a problem to be solved in the prior application, is avoided, and thus is preferable.

(34) After the shell layer 1a is further modeled in the height direction to be modeled to the height H of the final modeling object (FIG. 6), the core material 2 is filled to the height H again (FIG. 7). Here, the modeling of the shell layer 1a and the filling of the core material 2 into the core portion 1b are completed. After that, the entire three-dimensional modeling object 1 is placed in, for example, an appropriate heating furnace to apply thermal energy to the core material, or the entire area is irradiated with an active energy ray, which cures the core material 2 and completes the modeling of the three-dimensional modeling object 1 shown in FIG. 1.

(35) In the present embodiment, the modeling of the shell layer 1a of the three-dimensional modeling object 1 is performed by dividing the modeling into three steps in the lamination modeling direction. Of course, this number of steps may be arbitrary. When the shape of the core portion 1b is relatively simple and the core material 2 can be easily filled in, or when the size of the three-dimensional modeling object 1, that is, the internal volume of the core portion 1b is smaller relative to the hourly supply capacity of the core material 2, the number of divisions of the shell layer 1a can be small. In an extreme case, it may be possible to model the shell layer 1a at once and then fill the core material 2 therein.

(36) Next, as a second embodiment of the present invention, a schematic configuration diagram and a modeling procedure of a composite material 3D printer 100 will be described with reference to FIGS. 8 to 20, that uses a modeling apparatus by a vat polymerization, which is one of additive manufacturing methods, to form a shell layer, and uses a reinforced resin in which a reinforcing material is dispersed in a thermosetting resin, as a core material.

(37) In FIG. 8 and subsequent drawings, the arrow x direction in the drawing is the x axis direction, the arrow z direction is the z axis direction, and the y axis direction is perpendicular to the paper surface.

(38) The composite material 3D printer 100 mainly includes a modeling tank 111 in which an ultraviolet curable resin 121, which is a shell material, is stored, a laser optical system 112, and a core material supply system 113.

(39) An ultraviolet curable resin 121 is stored in the modeling tank 111, and its liquid surface position can be maintained and adjusted at a predetermined position by an ultraviolet curable resin supply system (not shown). As the ultraviolet curable resin 121, known ones such as epoxy type and acrylic type can be used. A modeling table 128 is provided in the modeling tank 111. The modeling table 128 is provided for supporting a three-dimensional modeling object 101, and can be moved and installed at an arbitrary position in the z axis direction in the drawing by a driving mechanism (not shown).

(40) The laser optical system 112 includes an ultraviolet laser 114 and a scanning optical system 115, and the ultraviolet laser light 130 emitted from the ultraviolet laser 114 can scan in a predetermined range on the liquid surface (that is, the xy plane) of the ultraviolet curable resin 121 by the scanning optical system 115. The ultraviolet curable resin 121 is cured by irradiation of the ultraviolet laser light 130 to a predetermined depth from the liquid surface as indicated by 124 in the drawing. This curing depth is generally about 0.1 mm to 0.2 mm. Of course, it is possible to adjust the curing depth by adjusting the output of the ultraviolet laser 114. If the upper surface of the modeling table 128 is located at a depth that is about the curing depth from the liquid surface of the ultraviolet curable resin 121, the three-dimensional modeling object 101 is modeled on the modeling table 128.

(41) The core material supply system 113 pumps and supplies the core material 116 from the core material tank 117 which stores the core material 116 therein by the pump 119 through the piping systems 118b and 118a in order and discharges it from the tip of the nozzle 120. The nozzle 120 can be moved and fixed in each xyz direction in the drawing by a moving mechanism (not shown). Therefore, the piping system 118a has a flexible structure and material so as to follow the movement of the nozzle 120. The core material 116 is a thermosetting resin in which a reinforcing material is uniformly dispersed, and like the shell material 121, a known thermosetting resin such as an epoxy type or an acrylic type can be used.

(42) Hereinafter, a modeling procedure by the composite material 3D printer 100 will be sequentially described. Although in the present embodiment, an example in which the modeling of the shell layer 125 is divided into two steps and is modeled as illustrated, depending on the size of the three-dimensional modeling object 101 and the shape of the core portion 126, there is a case where the modeling may be performed once, and conversely, there is a case where two or more divisions are required. However, irrelevant to the number of divisions of the modeling of the shell layer, the same procedure is only repeated and there is no essential difference in the molding method.

(43) First, the first modeling is performed. The shell layer 125 is modeled on the modeling table 128 while scanning the ultraviolet laser light 130 and sequentially lowering the modeling table 128 by a predetermined height (depth) in the z direction. This state is shown in FIG. 9. The uncured ultraviolet curable resin and the uncured shell material 121a remain inside the modeled shell layer 125 (in the core portion 126).

(44) Next, the nozzle driving mechanism is operated to insert the nozzle 120 into the core portion 126, and the tip thereof is arranged near the bottom of the core portion 126 (FIG. 10). In this state, the pump 119 is driven to slowly discharge the core material 116 from the tip of the nozzle 120 and to supply the core material 116 to the core portion 126. As the core material 116 is discharged and supplied from near the bottom of the core portion 126, the remaining uncured shell material 121a overflows from the edges of the modeled shell layer 125, and the uncured shell material 121a in the core portion 126 is gradually replaced with the core material 116 from the bottom (FIG. 11). At this time, if the specific gravity of the core material 116 is larger than that of the shell material 121, the core material 116 tends to settle into the uncured shell material 121a by its own weight, and thus it is preferable because the replacement from the bottom of the core portion 116 can be realized more easily. In general, the material used as the reinforcing material is often one having a relatively high specific gravity such as carbon fiber, glass fiber, and inorganic material powder (so-called compound) such as silica, and therefore, in many cases, the specific gravity of the core material 116 becomes larger than that of the shell material 121.

(45) FIG. 12 shows a state where the replacement of the uncured shell material 121a and the core material 116 is completed.

(46) Then, the second modeling is started. First, the shell layer 125a is formed for the second time, and the state shown in FIG. 13 is obtained. At this time, inside the shell layers 125 and 125a, the core material 116a which has been injected in the first modeling is present at the bottom, and the uncured shell material 121b in the second molding of the shell layer 125a remains thereon.

(47) The nozzle driving mechanism is operated to position the tip of the nozzle 120 at the bottom of the core material 116a that has been injected in the first modeling (FIG. 14). In this state, the pump 119 is operated to slowly discharge and supply the core material 116 from the tip of the nozzle 120. As the core material 116 is slowly discharged and supplied as in the first modeling, the upper surface of the core material 116a that has been injected in the first modeling (interface between the injected core material 116a and the uncured shell material 121b) rises, the uncured shell material 121b overflows from the edge of the shell layer 125a, and the replacement of the uncured shell material 121b with the core material 116 proceeds (FIG. 15).

(48) When the replacement of the uncured shell material 121b with the core material 116 is completed, the nozzle 120 is retracted (FIG. 16), the modeling table is driven such that the modeling object is exposed on the liquid surface of the ultraviolet curable resin 121 (FIG. 17), and the three-dimensional modeling object 101 is removed from the modeling table 128.

(49) The modeling is completed by heating the removed three-dimensional modeling object 101 in a suitable heating furnace or the like to cure the core material 116 in the core portion 126.

(50) Now, with the injecting of the core material into the core portion 126, instead of injecting the core material 116 into the uncured shell materials 121a and 121b remaining in the core portion 126 as in this embodiment to replace the liquids with each other, it is also possible, in principle, to temporarily remove the uncured shell materials 121a and 121b remaining in the core portion 126 after modeling the shell layer 125 and inject the core material 116 into the core portion 126 that has become a space. In particular, when the shell layer 125 is modeled once, it is possible to inject the core material 116 into the core portion 121 after the shell layer 125 is modeled, and in a state in which the shell layer 125 is positioned on the liquid surface of the ultraviolet curable resin 121 or is further removed from the modeling table 128 and the remaining shell material 121a inside is removed (as illustrated in FIG. 18).

(51) However, in this case, the core material 116 is injected into the core portion 126 that has become a space by removing the uncured shell material 121a, and thus there is a case in which small spaces or gaps called voids are generated because of a slight air layer remaining at the inner surface of the shell layer 125, that is, at the interface between the shell layer 125 and the injected core material. Such small spaces and gaps are extremely unfavorable from the viewpoint of strength, rigidity, fatigue characteristics, etc. of the three-dimensional modeling object.

(52) On the other hand, it is preferable if the remaining uncured shell materials 121a and 121b and the core material 116 are replaced with each other by liquids as in this embodiment, because air is not present at the time of replacement of the two and the occurrence of such small spaces and gaps can be avoided in principle.

(53) Furthermore, when the liquids of the uncured shell materials 121a and 121b and the like and the core material 116 are replaced with each other, the uncured shell materials 121a and 121b may slightly remain at the interface between the inner surface of the shell material 125 and the core material 116. However, this slightly remaining uncured shell materials 121a and 121b can be cured by irradiating the entire three-dimensional modeling object 101 with ultraviolet rays after completion of modeling, and will not continue to remain in an uncured state at least inside the three-dimensional modeling object 101. In general, an ultraviolet curable resin is normally transparent relative to ultraviolet rays even after curing due to its modeling characteristics, and such curing of the uncured shell materials 121a and 121b can be easily achieved.

(54) Furthermore, in the second modeling of the core portion, as shown in FIG. 19, the tip of the nozzle 120 may be in the shell material 121b remaining in the core portion 126 when the second modeling of the shell 125a is performed. When the specific gravity of the core material 116 is heavier than that of the shell material, the discharged core material 116 may settle in the shell material 121a and be newly deposited on the upper surface of the injected shell material 116a. However, in this case, as shown in FIG. 20, the shell material 121b may be slightly sandwiched and left as the interface remaining shell material 129 at the interface between the newly injected core material 116 and the already injected core material 116a, which is not preferable. This interface remaining shell material 129 remains in an uncured state even after the core material 116 is heated and cured in a subsequent modeling step, and even if it is subsequently irradiated with ultraviolet rays, since it exists in the inner part of the shell layer 125 and the core portion 116, it is difficult for ultraviolet rays to reach in many cases, and it remains uncured almost permanently, which is not preferable. In particular, when the reinforcing material in the core material 116 is carbon fiber or the like, it is extremely difficult to cure the interface remaining shell material 128 because of the UV impermeability of the carbon fiber.