JP7515055B2 - Manufacturing method of three-dimensional shaped object and three-dimensional shaped object - Google Patents

Description

The present invention relates to a method for manufacturing a three-dimensionally shaped object. More specifically, the present invention relates to a method for manufacturing a three-dimensionally shaped object in which a solidified layer is formed by irradiating a powder layer with a light beam.

A method for manufacturing a three-dimensional object by irradiating a powder material with a light beam (generally referred to as "powder bed fusion") has been known in the art. This method manufactures a three-dimensional object by alternately and repeatedly forming a powder layer and a solidified layer based on the following steps (i) and (ii).
(i) A step of irradiating a predetermined portion of the powder layer with a light beam to sinter or melt and solidify the powder at the predetermined portion to form a solidified layer.
(ii) forming a new powder layer on the resulting solidified layer and similarly irradiating the light beam to form a further solidified layer;

This manufacturing technique makes it possible to produce complex three-dimensional objects in a short period of time. When inorganic metal powder is used as the powder material, the resulting three-dimensional object can be used as a mold. On the other hand, when organic resin powder is used as the powder material, the resulting three-dimensional object can be used as various models.

Take the case where metal powder is used as the powder material and the three-dimensional shaped object obtained by using it is used as a mold as an example. As shown in FIG. 7, first, the squeegee blade 23 is moved to form a powder layer 22 of a predetermined thickness on the shaping plate 21 (see FIG. 7(a)). Next, a light beam L is irradiated to a predetermined location of the powder layer 22 to form a solidified layer 24 from the powder layer 22 (see FIG. 7(b)). Subsequently, a new powder layer is formed on the obtained solidified layer, and a new solidified layer is formed by irradiating the light beam again. In this way, by alternately repeating the formation of the powder layer and the solidified layer, the solidified layers 24 are stacked (see FIG. 7(c)), and finally, a three-dimensional shaped object consisting of the stacked solidified layers 24 can be obtained. The solidified layer 24 formed as the bottom layer is bonded to the shaping plate 21, so that the three-dimensional shaped object and the shaping plate 21 form an integrated object, and the integrated object can be used as a mold.

JP 1-502890 A

For example, a three-dimensionally shaped object 300' having a low-density portion 100a' and a high-density portion 200a' may be manufactured according to the above-mentioned powder bed fusion method and used as a mold. In this case, the low-density portion 100a' may be used as a ventilation portion 100' extending in a predetermined direction to allow ventilation to the outside in order to supply gas into the mold cavity or to remove generated gas from the mold cavity to the outside (see Figures 10(a) to (d)).

Here, the inventors of the present application have newly discovered that when the obtained three-dimensional shaped object 300' has a ventilation section 100', the following technical problem may arise. Specifically, in order to prevent the resin material from penetrating into the ventilation section 100' during molding, the ventilation section 100' forms a minute space, but there are cases in which such a minute space is not continuous in a predetermined direction to allow ventilation with the outside. In such cases, it may be difficult to suitably supply gas into the mold cavity or to suitably remove generated gas from the mold cavity to the outside.

The present invention has been made in consideration of these circumstances. That is, the object of the present invention is to provide a method for manufacturing a three-dimensionally shaped object having a ventilation portion that allows suitable ventilation with the outside, and a three-dimensionally shaped object obtained from the method.

In order to achieve the above object, in one embodiment of the present invention,
A method for manufacturing a three-dimensional shaped object by alternately stacking powder layers and solidified layers by the steps of: (i) irradiating a predetermined portion of a powder layer with a light beam to sinter or melt and solidify the powder at the predetermined portion to form a solidified layer; and (ii) forming a new powder layer on the obtained solidified layer, and irradiating a predetermined portion of the new powder layer with a light beam to form a further solidified layer,
Producing the three-dimensional shaped object having a high density portion and a low density portion;
At least a part of the low density portion is used as a ventilation portion,
At least two main ventilation parts are formed as the ventilation parts, each extending in a predetermined direction to be able to ventilate with the outside,
The method for manufacturing a three-dimensional shaped object further includes forming a sub-ventilation portion that connects at least one of the main ventilating portions and the other main ventilating portion adjacent to each other.

In order to achieve the above object, in one embodiment of the present invention,
A three-dimensional shape having a high density portion and a low density portion,
At least a part of the low density portion is used as a ventilation portion,
The ventilation section includes at least two main ventilation sections extending in a predetermined direction to be able to ventilate with the outside, and a sub-ventilation section that connects at least one adjacent main ventilation section to the other main ventilation section, thereby providing a three-dimensional shaped object.

According to one embodiment of the present invention, it is possible to manufacture a three-dimensional shaped object having a ventilation section that allows suitable ventilation to the outside.

1A to 1C are schematic cross-sectional views illustrating a method for manufacturing a three-dimensional object according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing a method for manufacturing a three-dimensional object having a ventilation portion. FIG. 13 is a schematic perspective view showing a method for manufacturing a three-dimensional object having a ventilation portion. FIG. 1 is a schematic top view of a main vent surrounded by a high-density portion and a low-density portion. Schematic cross-sectional view of an embodiment in which a high-density portion surrounding a main ventilation portion has a low-density portion locally therein. FIG. 1 is a schematic top view of an embodiment in which a high-density portion surrounding a main vent has a low-density portion locally therein. FIG. 1 is a schematic cross-sectional view showing a three-dimensional object having a sub-ventilation portion with a circular cross-section. 6(a): overall schematic perspective view showing the production of a three-dimensional shaped object having a sub-ventilation portion with a circular cross section; FIG. 6(b): schematic cross-sectional view showing an embodiment of light beam irradiation adjustment; FIG. 6(c): schematic cross-sectional view showing the generation of a protuberance; FIG. 6(d): schematic cross-sectional view showing an embodiment of cutting work on the protuberance) 7A and 7B are cross-sectional views showing a schematic process of a photolithography hybrid fabrication process in which a powder bed fusion method is implemented (FIG. 7A: when a powder layer is formed, FIG. 7B: when a solidified layer is formed, FIG. 7C: during lamination). FIG. 1 is a perspective view showing a schematic configuration of a laser lithography hybrid processing machine; Flowchart showing the general operation of a stereolithography hybrid processing machine Schematic diagrams illustrating the technical problems of the present application (FIG. 10(a): schematic overall perspective view of a three-dimensionally shaped object including a ventilation part, FIG. 10(b): schematic top view of the ventilation part, FIG. 10(c): schematic cross-sectional view of the ventilation part, FIG. 10(d): schematic partial enlarged view of the ventilation part)

Below, an embodiment of the present invention will be described in more detail with reference to the drawings. The shapes and dimensions of various elements in the drawings are merely illustrative and do not reflect the actual shapes and dimensions.

In this specification, "powder layer" means, for example, "a metal powder layer made of metal powder" or "a resin powder layer made of resin powder." Also, "a predetermined location of the powder layer" essentially refers to the area of the three-dimensional shaped object to be manufactured. Therefore, by irradiating the powder present at the predetermined location with a light beam, the powder is sintered or melted and solidified to form a three-dimensional shaped object.

The "upper" or "lower" directions described directly or indirectly in this specification are directions based on the positional relationship between the modeling plate and the three-dimensional object, for example, and the side on which the three-dimensional object is manufactured using the modeling plate as a reference is the "upper" direction, and the opposite side is the "lower" direction.

Powder Bed Fusion
First, the powder bed fusion method, which is the premise of the manufacturing method of the present invention, will be described. In particular, the laser lithography hybrid processing, which additionally performs cutting of a three-dimensional shaped object in the powder bed fusion method, will be taken as an example. Figure 7 shows a schematic diagram of the process mode of the laser lithography hybrid processing, and Figures 8 and 9 show the main configuration and operation flow charts of a laser lithography hybrid processing machine that can perform the powder bed fusion method and cutting, respectively.

As shown in FIG. 8, the stereolithography hybrid machine 1 includes a powder layer forming section 2, a light beam irradiating section 3, and a cutting section 4.

The powder layer forming unit 2 is for forming a powder layer by laying down a powder such as metal powder or resin powder to a predetermined thickness. The light beam irradiating unit 3 is for irradiating a light beam L onto a predetermined location of the powder layer. The cutting unit 4 is for cutting the surface of the laminated solidified layer, i.e., the surface of the three-dimensional shaped object.

As shown in FIG. 7, the powder layer forming section 2 mainly comprises a powder table 25, a squeegee blade 23, a modeling table 20, and a modeling plate 21. The powder table 25 is a table that can move up and down within a powder material tank 28 whose periphery is surrounded by a wall 26. The squeegee blade 23 is a blade that can move horizontally to supply the powder 19 on the powder table 25 onto the modeling table 20 to obtain a powder layer 22. The modeling table 20 is a table that can move up and down within a modeling tank 29 whose periphery is surrounded by a wall 27. And the modeling plate 21 is a plate that is placed on the modeling table 20 and serves as the base for a three-dimensionally shaped object.

As shown in FIG. 8, the light beam irradiation unit 3 mainly comprises a light beam oscillator 30 and a galvanometer mirror 31. The light beam oscillator 30 is a device that emits a light beam L. The galvanometer mirror 31 is a means for scanning the emitted light beam L onto the powder layer 22, i.e., a scanning means for the light beam L.

As shown in FIG. 8, the cutting unit 4 mainly comprises an end mill 40 and a drive mechanism 41. The end mill 40 is a cutting tool for cutting the surface of the laminated solidified layer, i.e., the surface of the three-dimensional shaped object. The drive mechanism 41 moves the end mill 40 to the desired location to be cut.

The operation of the photo-fabrication combined processing machine 1 will be described in detail. As shown in the flow chart of FIG. 9, the operation of the photo-fabrication combined processing machine 1 is composed of a powder layer forming step (S1), a solidified layer forming step (S2), and a cutting step (S3). The powder layer forming step (S1) is a step for forming the powder layer 22. In the powder layer forming step (S1), the modeling table 20 is first lowered by Δt (S11) so that the level difference between the upper surface of the modeling plate 21 and the upper end surface of the modeling tank 29 is Δt. Next, after the powder table 25 is raised by Δt, the squeegee blade 23 is moved horizontally from the powder material tank 28 toward the modeling tank 29 as shown in FIG. 7(a). This allows the powder 19 arranged on the powder table 25 to be transferred onto the modeling plate 21 (S12), and the powder layer 22 is formed (S13). Examples of powder materials for forming the powder layer 22 include metal powder with an average particle size of about 5 μm to 100 μm and resin powder such as nylon, polypropylene, or ABS with an average particle size of about 30 μm to 100 μm. After the powder layer 22 is formed, the process proceeds to the solidified layer formation step (S2). The solidified layer formation step (S2) is a step of forming the solidified layer 24 by irradiating a light beam. In the solidified layer formation step (S2), a light beam L is emitted from the light beam oscillator 30 (S21), and the light beam L is scanned to a predetermined location on the powder layer 22 by the galvanometer mirror 31 (S22). This causes the powder at a predetermined location of the powder layer 22 to be sintered or melted and solidified, forming the solidified layer 24 as shown in FIG. 7(b) (S23). The light beam L may be a carbon dioxide gas laser, an Nd:YAG laser, a fiber laser, or ultraviolet light.

The powder layer forming step (S1) and the solidified layer forming step (S2) are alternately performed. As a result, multiple solidified layers 24 are stacked as shown in FIG. 7(c).

When the laminated solidified layer 24 reaches a predetermined thickness (S24), the process proceeds to the cutting step (S3). The cutting step (S3) is a step for cutting the surface of the laminated solidified layer 24, i.e., the surface of the three-dimensional shaped object. The cutting step is started by driving the end mill 40 (see FIG. 7(c) and FIG. 8) (S31). For example, if the end mill 40 has an effective blade length of 3 mm, a cutting process of 3 mm can be performed along the height direction of the three-dimensional shaped object, so if Δt is 0.05 mm, the end mill 40 is driven when 60 layers of the solidified layer 24 are laminated. Specifically, the surface of the laminated solidified layer 24 is subjected to a cutting process while moving the end mill 40 by the driving mechanism 41 (S32). At the end of such cutting step (S3), it is determined whether or not the desired three-dimensional shaped object has been obtained (S33). If the desired three-dimensional shaped object has not yet been obtained, the process returns to the powder layer formation step (S1). Thereafter, the powder layer formation step (S1) through the cutting step (S3) are repeated to further stack solidified layers and perform cutting processes, ultimately resulting in the desired three-dimensional object.

[Characteristics of the present invention]
Hereinafter, a method for producing a three-dimensionally shaped object according to one embodiment of the present invention will be described. Note that this embodiment of the present invention is premised on producing a three-dimensionally shaped object having a low-density portion and a high-density portion, and using at least a part of the low-density portion as a ventilation portion.

The inventors of the present application conducted extensive research into a method for manufacturing a three-dimensional shaped object having a ventilation section that allows suitable ventilation with the outside. As a result, the inventors of the present application came up with the present invention, which has the following technical idea.

(Technical idea of the present invention)
Specifically, the inventors of the present application have devised the present invention having the technical idea that "the ventilation section 100 is composed of two or more main ventilation sections 101 extending in a predetermined direction to be able to ventilate with the outside, and sub-ventilation sections 102 that connect at least one adjacent main ventilation section 101A to the other main ventilation section 101B" (see Figs. 1, 2A, and 2B).

According to this technical idea, at least one adjacent main ventilation section 101A and the other adjacent main ventilation section 101B can communicate with each other through the sub-ventilation section 102. That is, the sub-ventilation section 102 can function as a communication member. As a result, when the main ventilation section 101 forms a minute space, even if this minute space is not connected to the outside in a manner that allows ventilation, gas can be suitably moved between the adjacent main ventilation section 101A and the other adjacent main ventilation section 101B through the sub-ventilation section 102. As a result, when the three-dimensional shaped object 300 is used as, for example, a mold, it is possible to suitably supply gas into the mold cavity and suitably remove generated gas from the mold cavity to the outside through the ventilation section 100 having the main ventilation section 101 and the sub-ventilation section 102.

In this specification, the term "main ventilation section" refers to the section that mainly contributes to the ventilation of the three-dimensional shaped object. In this specification, the term "sub-ventilation section" refers to a secondary section that assists the ventilation function of the main ventilation section. In this specification, the term "high density section" refers to a section with a solidified density of 95-100%, the term "low density section" refers to a section with a solidified density of 0-70%, and the term "medium density section" refers to a section with a solidified density of 70-95%. Furthermore, in this specification, the term "low density section" refers to a component of the three-dimensional shaped object, and at least a part of all of the low density sections that are the component are used as ventilation sections. In other words, in this specification, the term "low density section" also includes low density sections that are used for purposes other than ventilation sections.

In this specification, "top view" refers to the final three-dimensional object (finished product) as viewed from above. In this specification, "plan view" refers to the solidified layer during the production of the three-dimensional object (finished product) as viewed from above.

In this specification, the term "solidified density (%)" essentially means the solidified cross-sectional density (occupancy rate of solidified material) obtained by image processing of a cross-sectional photograph of a three-dimensional shaped object. The image processing software used is Scion Image ver. 4.0.2 (freeware from Scion Corporation), and after binarizing the cross-sectional image into solidified parts (white) and void parts (black), the total number of pixels Px _all of the image and the number of pixels Px _white of the solidified parts (white) are counted, and the solidified cross-sectional density ρ _S can be calculated by the following formula 1.
[Formula 1]

The following is a detailed description of a method for manufacturing a three-dimensional object having a ventilation section with a main ventilation section and a sub-ventilation section (see Figures 2A and 2B).

Specifically, the method for manufacturing a three-dimensional shaped object according to one embodiment of the present invention includes a step of stacking a plurality of solidified layers, each having a "portion that will become a part of the main ventilation section 101 and a portion that will become a part of the sub-ventilation section that is continuous therewith" in a predetermined substantially planar direction, along a stacking direction using a light beam according to the powder bed fusion method. The "substantially planar direction" here refers to a direction (e.g., a substantially perpendicular direction) different from the extension direction of the main ventilation section 101 that is ultimately formed. Note that the solidified layer located at least on the top surface of the finally obtained three-dimensional shaped object must be a solidified layer that has only a portion that will become a part of the main ventilation section, from the viewpoint of preventing the resin material from penetrating into the ventilation section during molding when the object is used as a mold. In other words, the solidified layer located at least on the top surface must not include "a portion that will become a part of the sub-ventilation section that is continuous with the portion that will become a part of the main ventilation section 101".

This allows the manufacture of a three-dimensionally shaped object 300 according to one embodiment of the present invention, which has a main ventilation section 101 and a sub ventilation section 102 inside (see Figures 1, 2A and 2B).

The obtained three-dimensionally shaped object 300 according to one embodiment of the present invention has the following characteristic configuration. Specifically, the three-dimensionally shaped object 300 according to one embodiment of the present invention has a high-density portion 200 and a low-density portion, at least a portion of which is used as a ventilation portion 100. However, without being limited thereto, the three-dimensionally shaped object 300 according to one embodiment of the present invention may further have a medium-density portion from the viewpoint of achieving both breathability and strength.

This ventilation section 100 has at least two main ventilation sections 101 that extend in a predetermined direction to allow ventilation with the outside, and a sub-ventilation section 102 that connects at least one adjacent main ventilation section 101A to the other adjacent main ventilation section 101B.

The sub-ventilation section 102 formed inside the three-dimensional shaped object 300 extends in a direction different from the extension direction of the main ventilation section (e.g., a substantially perpendicular direction). As a result, the sub-ventilation section 102 is positioned so as to cross between the main ventilation sections that are spaced apart from each other. In other words, in one embodiment of the present invention, the sub-ventilation section 102 can function as a communication member for communicating at least two adjacent main ventilation sections 101.

According to this configuration, at least one adjacent main ventilation section 101A and the other adjacent main ventilation section 101B can communicate with each other through the sub-ventilation section 102. As a result, when the main ventilation section 101 forms a minute space, even if this minute space is not connected to the outside in a manner that allows ventilation, gas can be suitably moved between the adjacent main ventilation section 101A and the other adjacent main ventilation section 101B through the sub-ventilation section 102. As a result, when the three-dimensional shaped object 300 is used as, for example, a mold, gas can be suitably supplied into the mold cavity through the ventilation section 100 having the main ventilation section 101 and the sub-ventilation section 102, and generated gas can be suitably removed from the mold cavity to the outside.

In addition, from the viewpoint of ensuring the ventilation volume of the finally obtained ventilation section 100 when the solidified layer is formed, it is preferable that the "portion that will become part of the main ventilation section 101" and the "portion that will become part of the sub ventilation section 102" are each low density portions (e.g., solidified density of 40% or less). Furthermore, from the viewpoint of more preferably ensuring the ventilation volume of the finally obtained ventilation section 100, it is more preferable that the "portion that will become part of the main ventilation section 101" and the "portion that will become part of the sub ventilation section 102" each have a solidified density of 0%. In this case, the powder that has not been irradiated with the light beam is allowed to fall along the direction of gravity during the manufacturing process, and the powder can be removed from inside the solidified layer.

Below, we will explain some possible aspects of one embodiment of the present invention.

First, when manufacturing the above-mentioned three-dimensional shaped object 300, it is preferable to repeatedly form a solidified layer 24a including a portion that will become part of the ventilation section extending in a predetermined direction (e.g., corresponding to the X direction) and a solidified layer 24b including a portion that will become part of the ventilation section extending in a direction approximately perpendicular to the predetermined direction (e.g., corresponding to the Y direction).

Specifically, it is preferable to repeatedly form a plurality of solidified layers 24a including "a portion that will become part of the main ventilation section and a portion _24a1 , _{24a3 that} will become part of the sub-ventilation section that is continuous therewith" and a plurality of solidified layers 24b including "a portion that will become part of the main ventilation section and a portion _24b1 , _24b3 that will become part of the sub-ventilation section that is continuous therewith" extending in the Y direction (see Figures 2A and 2B).

In this case, for example, a solidified layer (one layer) having the following form can be formed: As an example, as shown in Fig. 2A, the solidified layer (one layer) can be formed so that a plurality of portions (low density portions) _24a3 , each of which is a part of the ventilation portion and has a continuous form, are arranged in parallel at a predetermined interval (i.e., in stripes).

This allows the ventilation section inside the final three-dimensional object to have a tower-like shape. As a result, compared to manufacturing an object by stacking solidified layers that include a ventilation section that extends in only one direction (e.g., the X direction), the area and/or number of gas movement paths can be increased. This allows for more optimal gas ventilation (gas supply from outside/exhaust of internal gas to outside).

2B, in forming the solidified layer (one layer), "a portion that will become a part of the main ventilation part and a portion that will become a part of the continuous sub-ventilation part" _24a1 , _24b1 can be provided discontinuously, and "a portion that will become a part of the main ventilation part" _24a2 , _24b2 can be provided discontinuously. In this case, the "portion that will become a part of the main ventilation part and a portion that will become a part of the continuous sub-ventilation part" and the "portion that will become a part of the main ventilation part" may be formed in parallel with a predetermined interval between them.

As a result, in a given solidified layer (one layer), the proportion of the continuous portion (low density portion) can be relatively reduced compared to when the portion that becomes part of the continuous ventilation portion is formed in stripes. In other words, in a given solidified layer (one layer), the proportion of the high density portion can be relatively increased. This makes it possible to achieve a good balance between favorable gas movement due to the presence of the sub-ventilation portion and the assurance of a predetermined strength in the three-dimensional shaped object that is finally obtained.

In addition, the following effects can be achieved in both the configurations shown in Figures 2A and 2B. Specifically, when a three-dimensional object is manufactured by stacking multiple solidified layers, in which the portion that will become part of the ventilation portion extends only in a predetermined direction (e.g., the X direction) along the stacking direction, the portion that will become part of the ventilation portion extends only in the predetermined direction, which may result in insufficient resistance to pressure from a direction other than the predetermined direction. In this regard, in the configurations shown in Figures 2A and 2B, the portion that will become part of the ventilation portion extends, for example, in the X direction and the Y direction, so that the three-dimensional object finally obtained can be suitably secured to have resistance to external pressure not only in the predetermined direction but also in a direction approximately perpendicular to the predetermined direction.

In view of the above, according to the form shown in Figures 2A and 2B, when the solidified layer is formed, at least two portions that will become part of the main ventilation section in a planar view can be formed at a predetermined interval in at least one of the vertical direction (corresponding to the X direction) and horizontal direction (corresponding to the Y direction). This makes it possible to form at least two main ventilation sections 101 that are ultimately obtained in at least one of the vertical and horizontal directions (see Figures 2A and 2B). In other words, the body portion (e.g., the high-density portion) surrounding the main ventilation section can form a lattice structure (i.e., a lattice structure). This makes it possible to ensure multiple gas movement paths, enabling more optimal gas ventilation (gas supply from the outside/exhaust of internal gas to the outside).

From the viewpoint of effective and efficient ventilation, when forming a solidified layer according to the form shown in FIG. 2B, for example, it is preferable to form at least two parts of the main ventilation section having approximately the same planar dimensions in at least one of the vertical and horizontal directions at approximately the same intervals. This ultimately makes it possible to form at least two main ventilation sections having approximately the same planar dimensions in at least one of the vertical and horizontal directions at approximately the same intervals (see FIG. 2). This makes it possible to ensure multiple gas movement paths and to avoid variations in ventilation resistance.

In addition, when manufacturing a shaped object that includes multiple ventilation sections arranged in parallel at a predetermined interval, the multiple ventilation sections may be formed so that the extension (longitudinal) dimension of the ventilation section located in the central portion in a cross-sectional view is relatively longer than the extension dimension of the ventilation sections located in the side portions. In this case, the main ventilation section located in the side portion, which has a relatively long extension dimension, may be more likely not to be ventilatively continuous with the outside due to its larger extension dimension than the main ventilation section located in the central portion, which has a relatively short extension dimension.

In this regard, according to one embodiment of the present invention, even if the extension dimension of the ventilation section (corresponding to the main ventilation section) located in the side section is relatively large, at least the main ventilation section located in the side section is connected to another adjacent main ventilation section via the sub-ventilation section. This allows gas to be suitably moved between the main ventilation section located in the side section with a relatively long extension dimension and another adjacent main ventilation section via the sub-ventilation section.

In one embodiment, the main ventilation section 101 is surrounded by a high-density section 200 and a low-density section 100, each of which extends in the extension direction (longitudinal direction) of the main ventilation section 101 when viewed from above, and at least the low-density section 100 can be used as a sub-ventilation section 102 (see FIG. 3).

In such a case, the high density portion 200, which is a component surrounding the main ventilation portion 101, can contribute to ensuring the strength of the area in which the main ventilation portion is formed. In addition, the low density portion 100 (sub ventilation portion 102), which is a component surrounding the main ventilation portion 101, can function as a communication member for moving gas between adjacent main ventilation portions 101A and 102B.

In particular, if the solidification density of the portion that will become the main ventilation portion 101A is 0%, the main ventilation portion 101A that is ultimately obtained will be hollow, and it may not be easy to ensure sufficient strength against external pressure. Even in such a case, according to this embodiment, it is possible to preferably ensure strength in the area where the main ventilation portion is formed and to preferably move gas between two adjacent main ventilation portions 101.

It is preferable to locally form a low-density portion as a sub-ventilation portion 101 within the high-density portion 200 extending in the extension direction (longitudinal direction) of the main ventilation portion 101.

In the embodiment shown in FIG. 3, the low-density portion 100 (sub-ventilation portion 102), which is a component surrounding the main ventilation portion 101, needs to have a certain solidification density (e.g., 40%) in order to function as a "wall." Therefore, gas may not move easily through the sub-ventilation portion 102 compared to when the final sub-ventilation portion 102 is hollow.

Therefore, as described above, a low-density portion serving as a sub-ventilation portion 101 is locally formed within the high-density portion 200 extending in the extension direction (longitudinal direction) of the main ventilation portion 101. This makes it possible to increase the number of movement path patterns for gas movement between two adjacent main ventilation portions 101.

In one embodiment, the main ventilation section 101 is surrounded by a high-density portion 200 extending in the extension direction (longitudinal direction) of the main ventilation section 101 when viewed from above, and a low-density portion serving as a sub-ventilation section 102 can be locally formed within the high-density portion 200 (see Figures 4A and 4B).

In such a case, the high density portion 200, which is a component surrounding the main ventilation portion 101, can contribute to ensuring the strength of the area in which the main ventilation portion is formed. In addition, gas movement between two adjacent main ventilation portions 101 can occur via the sub-ventilation portion 102 (low density portion) formed locally within the high density portion 200.

In this embodiment, the main part of the "wall" surrounding the main ventilation part 101 is composed of a high-density part through which gas passage and movement is difficult. Therefore, compared to the embodiment shown in FIG. 3, the area through which gas passage and movement is possible is limited to the sub-ventilation part 102 formed locally within the high-density part 200. Therefore, from the viewpoint of achieving favorable gas passage and movement, in the embodiment shown in FIG. 4A and FIG. 4B, it is preferable that the solidification density of the part that becomes the sub-ventilation part 102 is 0%.

This allows the final sub-ventilation section 102 to be hollow. Such a hollow sub-ventilation section 102 allows gas to move favorably between two adjacent main ventilation sections 101.

However, without being limited thereto, when the solidified layer is formed, if at least one of the "portion that will become part of the main ventilation section 101" and the "portion that will become part of the sub ventilation section 102" is a low-density portion with a solidification density of approximately 40%, at least one of the main ventilation section 101 and the sub ventilation section 102 that is ultimately obtained can be a porous section. In this case, the size of a single void in the main ventilation section 101 can be made smaller than in the above-mentioned hollow state. Therefore, when the finally obtained molded object 300 is used as a mold, it is possible to more effectively prevent the intrusion of the resin material into the ventilation section 100 during molding.

Note that the present invention is not limited to the configuration shown in FIG. 3 and the configuration shown in FIG. 4B. For example, when viewed from above, the main ventilation section can be surrounded by only the walls of the low-density section extending in the extension direction (longitudinal direction) of the main ventilation section 101, and the low-density section can be used as the sub-ventilation section 102. Note that the low-density section (sub-ventilation section 102), which is a component that surrounds the main ventilation section, needs to have a certain solidification density (e.g., 40%) in order to function as a "wall."

In other words, all of the low-density parts surrounding the main ventilation section 101 can function as communication members for transferring gas between adjacent main ventilation sections. Furthermore, when the walls surrounding the ventilation section are all made of low density, they can be formed with lower irradiation energy than the configuration shown in FIG. 3 and the configuration shown in FIG. 4B, which is preferable in terms of production efficiency.

In one embodiment, the powder bed fusion process can be used to form any cross-sectional shape for the sub-vent 102. The cross-sectional shape of the sub-vent 102 can be, but is not limited to, a rectangle, a square, a circle, a diamond, and/or a polygon.

For example, let us take the case where the final sub-ventilation section 102A has a circular cross-sectional shape and is hollow (see Figures 5 and 6(a) to (d)).

As shown in FIG. 5, it is preferable to form the sub-ventilation section 102A in a circular shape as a whole. When this shape is adopted, it is possible to ensure a relatively large formation area of the sub-ventilation section 102 compared to the case where the sub-ventilation section is formed only between two adjacent main ventilation sections 101. Furthermore, because of the circular shape, even if gas cannot move to another main ventilation section 101 during one revolution through the sub-ventilation section 102A, it is possible to preferably ensure an opportunity for gas to move to another main ventilation section 101 from the second revolution onwards.

If the final sub-ventilation section 102A has a circular cross-sectional shape and is hollow (see FIG. 6(a)), it is preferable to adopt the following configuration.

Specifically, in this case, during manufacturing, as shown in FIG. 6(b), a part of the solidified layer 24 surrounding the sub-ventilation portion 102A in cross-sectional view becomes an undercut portion 24E. As shown in FIG. 6(c), the undercut portion 24E may attract powder 19 located in the vicinity when irradiated with a light beam, resulting in a protuberance 50.

In view of these circumstances, it is preferable to set the irradiation energy of the light beam L when forming the undercut portion 24E relatively smaller than the irradiation energy of the light beam L when forming other parts of the solidified layer 24 other than the undercut portion 24E. This makes it possible to suppress the attraction of powder 19 located in the periphery when the light beam L is irradiated, which is caused by the small irradiation energy. This makes it possible to suppress the occurrence of the protuberance 50. As a result, it is possible to form a sub-ventilation portion 102A having a predetermined cross-sectional dimension.

In addition, instead of or in combination with the above-mentioned adjustment of the irradiation energy, the upper surface of the undercut portion 24E of the solidified layer 24 can be cut using a cutting tool 40 as shown in FIG. 6(d). Specifically, when forming a given solidified layer 24, it is preferable to perform the above-mentioned upper surface cutting so that the thickness of the undercut portion 24E after cutting and the thickness of the other parts of the solidified layer 24 other than the undercut portion 24E are approximately the same. This allows a new solidified layer 24 having the desired thickness and shape to be formed at a later time.

Although one embodiment of the present invention has been described above, this is merely a typical example within the scope of application of the present invention. Therefore, it will be readily understood by those skilled in the art that the present invention is not limited to this, and that various modifications can be made.

300 Three-dimensional shaped object 200 High density portion 100 Ventilation portion (low density portion)
101: Main ventilation section 102: Sub ventilation section 22: Powder layer 24: Solidified layer L: Light beam

Claims (13)

A method for manufacturing a three-dimensional object by alternately stacking powder layers and solidified layers by the steps of: (i) irradiating a predetermined portion of a powder layer with a light beam to sinter or melt and solidify the powder at the predetermined portion to form a solidified layer; and (ii) forming a new powder layer on the obtained solidified layer, and irradiating a predetermined portion of the new powder layer with a light beam to form a further solidified layer,
Producing the three-dimensional shaped object having a high density portion and a low density portion;
At least a part of the low density portion is used as a ventilation portion,
At least two main ventilation parts are formed as the ventilation parts, each extending in a predetermined direction to be able to ventilate with the outside,
a sub-ventilation portion is further formed to communicate at least one of the main ventilating portions and the other main ventilating portion adjacent to each other;
a sub ventilation portion that extends in a direction different from an extending direction of the main ventilation portion and that assists the ventilation function of the main ventilation portion. 2. The manufacturing method according to claim 1, wherein, when viewed from above, the main ventilation portion is surrounded by the high density portion and the low density portion each extending in the predetermined direction, at least the low density portion is used as the sub- ventilation portion, and the low density portion surrounding a part of the main ventilation portion and used as the sub-ventilation portion is a porous portion . The manufacturing method according to claim 2 , further comprising locally forming the low density portion as the sub-ventilation portion within the high density portion. The manufacturing method according to claim 1 , wherein, in a top view, the main ventilation portion is surrounded by the high density portion extending in the predetermined direction, and the low density portion as the sub ventilation portion is locally formed within the high density portion. The manufacturing method described in claim 4, wherein, when the sub-ventilation portion has a solidified density of 0% and a portion of the solidified layer surrounding the sub-ventilation portion has an undercut portion, the irradiation energy of the light beam when forming the undercut portion is relatively smaller than the irradiation energy of the light beam when forming other portions of the solidified layer other than the undercut portion. The manufacturing method according to any one of claims 1 to 5 , wherein at least two portions that become part of the main ventilation portion are formed in at least one of the vertical and horizontal directions at a predetermined interval in a plan view. The manufacturing method according to any one of claims 1 to 6, wherein the solidified layer includes a portion that will become a part of a main ventilation portion extending in a predetermined approximately planar direction and a portion that will become a part of a sub-ventilation portion continuous therewith, and is formed in a plurality of such solidified layers along a stacking direction, thereby forming the sub-ventilation portion. The manufacturing method described in claim 7, wherein the formation of the plurality of solidified layers and the formation of the plurality of solidified layers including a portion that will become a part of the main ventilation portion extending in a direction approximately perpendicular to the predetermined approximately planar direction and a portion that will become a part of the sub-ventilation portion continuous therewith are repeated. A three-dimensional shape having a high density portion and a low density portion,
At least a part of the low density portion is used as a ventilation portion,
the ventilation section includes at least two main ventilation sections extending in a predetermined direction to be able to ventilate with the outside, and a sub-ventilation section that connects at least one adjacent main ventilation section to the other adjacent main ventilation section ;
The sub ventilation portion extends in a direction different from an extending direction of the main ventilation portion and serves to assist the ventilation function of the main ventilation portion . 10. The three-dimensional shaped object according to claim 9, wherein, in a top view, the main ventilation portion is surrounded by the high density portion and the low density portion, each of which extends in the predetermined direction, at least the low density portion is used as the sub-ventilation portion, and the low density portion which surrounds a part of the main ventilation portion and is used as the sub-ventilation portion is a porous portion . 10. The three-dimensional shaped object according to claim 9, wherein, in a top view, the main ventilation portion is surrounded by the high density portion extending in the predetermined direction, and the low density portion serving as the sub ventilation portion is locally provided within the high density portion. The three-dimensionally shaped object according to claim 9 , wherein at least one of the main ventilation portion and the sub ventilation portion is a hollow portion. The three-dimensionally shaped object according to claim 9 , wherein at least one of the main ventilation portion and the sub ventilation portion is a porous portion.