JP2025161080A - Manufacturing method for three-dimensional objects - Google Patents

Abstract

To provide a method for manufacturing a three-dimensional molded object, capable of improving surface roughness and dimensional accuracy of a finished surface of the three-dimensional molded object.SOLUTION: A method for manufacturing a three-dimensional molded object is provided which includes a first molding step and a second molding step. In the first molding step, a first material layer forming step and a first solidifying step are repeatedly performed. In the first material layer forming step, after lowering a molding table 4, material powder is supplied to a molding region R on the molding table 4 to form a material layer 91 having a predetermined thickness. In the first solidifying step, laser light L is irradiated onto a predetermined irradiation region of the material layer 91 to form a solidified layer 92. In the second molding step, a second material layer forming step and a second solidifying step are performed. In the second material layer forming step, material powder is supplied to the molding region R with a height of the molding table 4 after the first molding step being fixed, to form the material layer 91 having a thickness smaller than the predetermined thickness. In the second solidifying step, laser light L is irradiated onto the predetermined irradiation region of the material layer 91 to form the solidified layer 92.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a three-dimensional object.

Powder Bed Fusion (PBD) is known as one method for manufacturing three-dimensional objects.

An example of a PBD-type device is the additive manufacturing device described in Patent Document 1. In this type of additive manufacturing device, a recoater head equipped with a material storage box and a blade is moved horizontally in one axial direction in a manufacturing space formed within a manufacturing tank. Metal powder material is supplied from the material storage box while the blade is used to level and flatten the powder material, forming a powder layer. A laser or electron beam is then irradiated onto a predetermined area of the powder layer using a laser irradiation device to form a sintered layer (solidified layer). A new powder layer is then formed on top of this solidified layer, and the laser or electron beam is irradiated to repeatedly form solidified layers, thereby stacking the solidified layers and producing a metal object of the desired shape.

Special Publication No. 1-502890

However, in the PBD method of manufacturing three-dimensional objects, high energy is spot-irradiated onto the material powder while scanning with a laser, causing the material powder to melt and solidify, and the object is then produced by layering solidified layers. Therefore, it is not easy to obtain an object of the desired density with the expected finished surface roughness within an acceptable building time.

The present invention was made in consideration of these circumstances, and aims to provide a method for manufacturing three-dimensional objects that can improve the finished surface roughness and dimensional accuracy of three-dimensional objects.

According to the present invention, the following inventions are provided.
[1] A method for manufacturing a three-dimensional object, comprising a first modeling process and a second modeling process, wherein in the first modeling process, a first material layer forming process and a first solidification process are repeatedly performed, wherein in the first material layer forming process, after lowering a modeling table, material powder is supplied to a modeling area on the modeling table to form a material layer of a predetermined thickness, and in the first solidification process, laser light is irradiated to a predetermined irradiation area of the material layer to form a solidified layer, and in the second modeling process, a second material layer forming process and a second solidification process are performed, wherein in the second material layer forming process, the material powder is supplied to the modeling area while keeping the height of the modeling table fixed after the first modeling process, to form the material layer having a thickness smaller than the predetermined thickness, and in the second solidification process, laser light is irradiated to the predetermined irradiation area of the material layer to form the solidified layer.
[2] The method for manufacturing a three-dimensional object according to [1], wherein the second modeling step is repeated one or more times.
[3] A method for manufacturing a three-dimensional object according to [1] or [2], wherein in the first modeling step, when the solidified layer is formed beyond a position that is lower by the predetermined thickness than the top surface height position in at least each region of the three-dimensional object to be manufactured, the second modeling step is started.
[4] A method for manufacturing a three-dimensional object according to any one of [1] to [3], wherein the laser light intensity in the second solidification step is lower than the laser light intensity in the first solidification step.
[5] A method for manufacturing a three-dimensional object according to any one of [1] to [4], wherein in the second material layer formation step, if a protruding abnormally sintered portion is detected in the solidified layer during the formation of the material layer, the formation of the material layer is temporarily stopped, and a removal step is performed to remove the abnormally sintered portion, and then the formation of the material layer is resumed.

The method for manufacturing a three-dimensional object according to the present invention comprises a first modeling process and a second modeling process in which modeling is performed while the height of the modeling table is fixed, making it possible to obtain a three-dimensional object with fine finished surface roughness and high dimensional accuracy.

1 is a schematic configuration diagram of an additive manufacturing apparatus 100 according to an embodiment of the present invention. FIG. 2 is a perspective view of a material layer forming device 3 of the additive manufacturing device 100. FIG. 2 is a perspective view of a recoater head 32 of the material layer forming apparatus 3. 1 is a flowchart showing a method for manufacturing a three-dimensional object according to an embodiment of the present invention. 10A and 10B are diagrams showing a first modeling step SA in the method for manufacturing a three-dimensional object using the additive manufacturing apparatus 100. FIG. 10A and 10B are diagrams showing a second modeling step SB in the method for manufacturing a three-dimensional object using the additive manufacturing apparatus 100.

The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an independent invention. Furthermore, elements in the following embodiments that are not defined in the claims are optional and can be omitted. Any number of "0"s (for example, one or two) may be added to the end of numerical values disclosed in the following description. For example, one or two "0"s may be added after "1.4" to make it "1.40" or "1.400."

1. Additive manufacturing device 100
1 shows an example of an additive manufacturing apparatus 100 used in the additive manufacturing method of this embodiment. The additive manufacturing apparatus 100 includes a chamber 1, a material layer forming device 3, a modeling table 4, an irradiation device 5, and a machining device 6. In a modeling region R provided on the modeling table 4 arranged in the chamber 1, a material layer (powder layer) 91 and a solidified layer 92 are repeatedly formed to form a desired three-dimensional object.

1.1 Chamber 1
The chamber 1 covers a printing region R, which is an area where a desired three-dimensional object is formed. The chamber 1 is connected to an inert gas supply/exhaust device (not shown). The inert gas supply/exhaust device supplies a predetermined concentration of inert gas to the chamber 1, thereby filling the chamber 1 with the inert gas. The inert gas, which contains fumes generated in the formation of the solidified layer 92, is exhausted from the chamber 1 and subjected to a fume removal process in the inert gas supply/exhaust device before being supplied to the chamber 1 for reuse. In this specification, the inert gas is a gas that does not substantially react with the material layer 91 or the solidified layer 92, and is selected from nitrogen gas, argon gas, helium gas, etc. depending on the type of molding material.

For example, as shown in FIG. 1, a window 1a is provided on the top surface of the chamber 1, serving as a transmission window for the laser light L output from the irradiation device 5. The window 1a is made of a material that can transmit the laser light L, and depending on the type of laser light L, is selected from quartz glass, borosilicate glass, or crystals of germanium, silicon, zinc selenide, or potassium bromide. For example, if the laser light L is a fiber laser or YAG laser, the window 1a can be made of quartz glass.

As shown in FIG. 1, a contamination prevention device 17 is provided on the upper surface of the chamber 1 to cover the window 1a. The contamination prevention device 17 includes a cylindrical housing 17a and a cylindrical diffusion member 17c disposed within the housing 17a. An inert gas supply space 17d is provided between the housing 17a and the diffusion member 17c.

In addition, an opening 17b is provided on the inside of a diffusion member 17c on the bottom surface of the housing 17a. The diffusion member 17c has a large number of fine holes, and clean inert gas supplied to the inert gas supply space 17d from the inert gas supply and exhaust device fills the clean chamber 17e through the fine holes and is then ejected from the opening 17b toward the bottom of the contamination prevention device 17. This configuration prevents fumes from adhering to the window 1a and removes fumes from the irradiation path of the laser light L.

1.2 Material layer forming device 3
The material layer forming apparatus 3 is provided inside the chamber 1. As shown in Fig. 2, the material layer forming apparatus 3 includes a base 31 and a recoater head 32 disposed on the base 31. The recoater head 32 is configured to be reciprocable in one horizontal axial direction by a recoater head driving device 33 incorporating a driving mechanism such as a motor.

As shown in Figures 3 and 4, the recoater head 32 includes a material storage section 32a, a material supply port 32b, and a material discharge port 32c. The material supply port 32b is located on the top surface of the material storage section 32a and serves as a receiving port for the material powder supplied to the material storage section 32a from a material supply unit (not shown). The material powder (powder material) is fine particles made of a single metal or alloy. The material discharge port 32c is located on the bottom surface of the material storage section 32a and discharges the material powder from the material storage section 32a. The material discharge port 32c has a slit shape extending in the longitudinal direction of the material storage section 32a. Flat blades 32fb and 32rb are provided on both side surfaces of the recoater head 32. The blades 32fb and 32rb flatten the material powder discharged from the material discharge port 32c to form a material layer 91.

1.3 Build table 4
1, the modeling table 4 is placed in the chamber 1, and a model is formed in a modeling region R on the modeling table 4. The modeling table 4 is driven by a modeling table driving device 41 and is movable in the vertical direction. During modeling, a base plate 90 is placed in the modeling region R, and a material layer forming device 3 supplies material powder to the upper surface of the base plate 90 to form a material layer 91.

1.4 Irradiation device 5
The irradiation device 5 irradiates the material layer 91 with laser light L or an electron beam to form a solidified layer 92. For example, as shown in FIG. 1 , the irradiation device 5 of this embodiment is provided above the chamber 1 and irradiates the laser light L onto an irradiation region of the material layer 91 formed in the manufacturing region R, melting and solidifying the material powder to form the solidified layer 92. As shown in FIG. 2 , the irradiation device 5 of this embodiment includes a laser light source 51, a focus control unit 53, an X-axis galvanometer mirror 55 a, a Y-axis galvanometer mirror 55 b, and actuators (not shown) that rotate the X-axis galvanometer mirror 55 a and the Y-axis galvanometer mirror 55 b, respectively.

The laser light source 51 generates laser light L. The laser light L may be any laser light capable of sintering or melting the material powder, and may be, for example, a fiber laser, a _CO2 laser, or a YAG laser. The focus control unit 53 includes a focus control lens therein and can focus the laser light L and adjust the spot diameter.

The laser light L that passes through the focus control unit 53 is scanned two-dimensionally in the X-axis direction, which is a single horizontal axis, and the Y-axis direction, which is another single horizontal axis perpendicular to the X-axis direction. Specifically, the laser light L is reflected by the X-axis galvanometer mirror 55a and scanned in the X-axis direction of the modeling region R, and is reflected by the Y-axis galvanometer mirror 55b and scanned in the Y-axis direction of the modeling region R. The laser light L reflected by the X-axis galvanometer mirror 55a and the Y-axis galvanometer mirror 55b passes through the window 1a and is irradiated onto the material layer 91 in the modeling region R, thereby forming a solidified layer 92.

The irradiation device 5 is not limited to the above-described configuration. For example, an fθ lens may be provided instead of the focus control unit 53. The irradiation device 5 may also be configured to form the solidified layer 92 by irradiating the material layer 91 with an electron beam instead of laser light L to solidify it.

Specifically, the irradiation device 5 may be configured to include a cathode electrode (not shown) that emits electrons, an anode electrode (not shown) that converges and accelerates the electrons, a solenoid (not shown) that forms a magnetic field to converge the electron beam in one direction, and a collector electrode (not shown) that is electrically connected to the material layer 91 to be irradiated and applies a voltage between it and the cathode electrode. In this case, the cathode electrode and anode electrode function as an output source that outputs the electron beam, and the solenoid functions as a scanning means that scans the electron beam. Note that the window 1a and the contamination prevention device 17 may be omitted, and the cathode electrode may be positioned so that it protrudes into the chamber 1. Furthermore, when an irradiation device 5 that irradiates an electron beam is used, the atmosphere inside the chamber 1 may be a noble gas atmosphere in a near-vacuum state. Noble gases are also sometimes called rare gases.

1.5 Machining equipment 6
1, the machining device 6 is provided inside the chamber 1. The machining device 6 is configured by attaching a tool (e.g., an end mill) for performing machining such as cutting to a machining head, and performs machining by moving the machining head appropriately in the horizontal and vertical directions.

2. Method for Manufacturing a Three-Dimensional Object Here, a method for manufacturing a three-dimensional object using the above-described additive manufacturing apparatus 100 will be described with reference to FIGS. 4 to 6. FIG. 4 is a flowchart showing a method for manufacturing a three-dimensional object. FIGS. 5 and 6 are diagrams showing a method for manufacturing a three-dimensional object using the additive manufacturing apparatus 100. FIGS. 5 and 6 show an enlarged view of the periphery of the manufacturing region R. The manufacturing method according to this embodiment includes a first manufacturing process SA and a second manufacturing process SB.

2.1 First modeling process SA
The first modeling process SA will be described with reference to Figure 5. The first modeling process SA includes a first material layer forming process SA1 and a first solidification process SA2. In the first material layer forming process SA1, after the modeling table 4 is lowered, material powder is supplied to the modeling region R on the modeling table 4 to form a material layer 91 of a predetermined thickness TA1. In the first solidification process SA2, laser light L is irradiated onto a predetermined irradiation region of the material layer 91 to form a solidified layer 92. The first material layer forming process SA1 and the first solidification process SA2 are repeatedly performed.

In the first modeling process SA, the first first material layer forming process SA1 is performed. In the first material layer forming process SA1, as shown in FIG. 5A, the modeling table 4 is lowered with the base plate 90 placed on it. At this time, the modeling table 4 is adjusted so that the distance from the top surface of the base plate 90 to the lower ends of the blades 32fb, 32rb of the recoater head 32 is the predetermined thickness TA1 of the material layer 91 to be formed. In this state, by moving the recoater head 32 from left to right in FIG. 5A, a first material layer 91 having the predetermined thickness TA1 is formed on the base plate 90 as shown in FIG. 5B.

Next, the first solidification step SA2 is performed. As shown in Figure 5C, the laser light L is adjusted to a predetermined laser light intensity, and the laser light L is irradiated onto a predetermined irradiation area of the first material layer 91, solidifying the first material layer 91 and forming a first solidified layer 92. Here, the material powder shrinks during the process of melting and solidifying due to irradiation with the laser light L, so the thickness TA2 of the solidified layer 92 is smaller than the thickness TA1 of the material layer 91.

Next, the second first material layer formation process SA1 is performed. As shown in Figure 5D, after the first solidified layer 92 is formed, the height of the modeling table 4 is lowered by the thickness TA2 of the solidified layer 92. In this state, the recoater head 32 is moved from the right to the left in Figure 5D, thereby forming a second material layer 91 that covers the first solidified layer 92, as shown in Figure 5E.

Furthermore, in the first material layer formation process SA1, if a protruding abnormal sintered portion is detected in the solidified layer 92 formed in the previous molding process when forming the material layer 91, the formation of the material layer 91 may be temporarily stopped, and a removal process may be performed to remove the abnormal sintered portion using the machining device 6. Once the removal process is completed, the formation of the material layer 91 is resumed.

Next, a second first solidification step SA2 is performed. As shown in Figure 5F, as in the first step, a second solidified layer 92 is formed by irradiating a predetermined irradiation area of the second material layer 91 with laser light L.

Furthermore, after the first solidification step SA2, it is determined whether the three-dimensional object has been formed to a predetermined height (branch SA3 in Figure 4). If the three-dimensional object has not been formed to the predetermined height, a NO determination is made, and the first material layer formation step SA1 is performed again. The first formation step SA is repeated until the three-dimensional object is formed to the predetermined height. For example, the first formation step SA can be configured to end and the second formation step SB begin when the height of the solidified layer 92 after the first solidification step SA2 exceeds a position that is at least a predetermined thickness TA1 lower than the top surface height position in each region of the three-dimensional object to be manufactured. Specifically, the second modeling process SB can be configured to start when the height of the solidified layer 92 after the first solidification process SA2 is between a height that initially exceeds a position that is a predetermined thickness TA1 lower than the top surface height position and a height that does not exceed a position that is a predetermined thickness TA2 lower than the top surface height position (i.e., a height one layer before the height of the model formed by the first solidification process SA2 reaches or exceeds the top surface height). The termination conditions for the two first modeling processes SA are explained below with specific examples.

(1) Case where the first modeling process SA ends when the solidified layer is first formed to a height exceeding a position that is lower than the uppermost surface height position by a predetermined thickness TA1 In this case, for example, if modeling is being performed with the uppermost surface height position in a region of a three-dimensional object to be manufactured being 10 mm, the thickness of the material layer 91 being 0.2 mm, and the thickness per layer of the solidified layer 92 being 0.05 mm, the first modeling process SA ends when the solidified layer 92 is first formed to a height of 9.85 mm, which is a position that exceeds the position of 9.8 mm that is lower than the uppermost surface height position by the predetermined thickness TA1. In other words, at the end of the first modeling process SA, the distance from the bottom surface of the three-dimensional object formed in the first modeling process SA to the bottom ends of the blades 32fb and 32rb of the recoater head 32 is 10 mm, which is equal to the height in the region of the three-dimensional object to be manufactured. When the second modeling process SB is started under these conditions, dimensions can be measured based on the positions of the blades 32fb and 32rb of the recoater head 32, making it possible to manufacture a three-dimensional model with excellent dimensional accuracy.

(2) Case where the first modeling process SA ends when the solidified layer is formed to a position higher than that in (1): Under the same modeling conditions as in the above example, the first modeling process SA may be configured to end when the solidified layer 92 is formed to a height of, for example, 9.9 mm. In this case, at the end of the first modeling process SA, the distance from the bottom surface of the three-dimensional object formed in the first modeling process SA to the bottom ends of the blades 32fb and 32rb of the recoater head 32 is 10.05 mm, which is larger by the thickness TA2 of the solidified layer than the height of the region of the three-dimensional object to be manufactured. When the second modeling process SB is started under these conditions, the number of repetitions of the second modeling process SB can be reduced, shortening the manufacturing time and obtaining a three-dimensional object with high dimensional accuracy.

2.2 Second modeling process SB
The second modeling process SB will be described with reference to FIG. 6 . The second modeling process SB includes a second material layer forming process SB1 and a second solidification process SB2. In the second material layer forming process SB1, material powder is supplied to the modeling region R while the height of the modeling table 4 is fixed after the first modeling process SA, to form a material layer 91 having a thickness TB1 smaller than the predetermined thickness TA1. In the second solidification process SB2, laser light L is irradiated to a predetermined irradiation region of the material layer 91 to form a solidified layer 92. FIG. 6 shows an example in which the second modeling process SB is started after the first modeling process SA has been performed five times. The second modeling process SB will be described below based on this example.

In the second modeling process SB, the first second material layer forming process SB1 is performed first. Figure 6A shows the state when the first modeling process SA is completed. By moving the recoater head 32 from the right to the left in Figure 6A while keeping the height of the modeling table 4 fixed, a sixth material layer 91 is formed with a thickness TB1 that is smaller than the thickness TA1 of the material layer 91 formed in the first material layer forming process SA1, as shown in Figure 6C.

The thickness TB1 of the material layer 91 formed in the first second material layer formation process SB1 is smaller than the thickness TA1 of the material layer 91 formed in the first material layer formation process SA1 by the thickness TA2 of the solidified layer 92. For example, if the thickness of the material layer 91 is 0.2 mm and the thickness of the solidified layer 92 formed is 0.05 mm, the thickness of the material layer 91 formed in the first second material layer formation process SB1 will be 0.15 mm.

Furthermore, in the second material layer formation process SB1, if a protruding abnormal sintered portion is detected in the solidified layer 92 formed in the previous molding process when forming the material layer 91, a removal process may be performed to remove the abnormal sintered portion, as shown in FIG. 6B. Specifically, in the removal process, the abnormal sintered portion is cut using a machining device 6 so that the solidified layer 92 is flat. Once the removal process is completed, formation of the material layer 91 resumes.

By performing the removal process, the movement of the recoater head 32 is not hindered by abnormally sintered areas, allowing the material layer 91 to be formed.

Next, the first second solidification step SB2 is performed. In the second solidification step SB2, laser light L is used, which has a lower laser light intensity than the laser light intensity in the first solidification step SA2. The laser light intensity in the second solidification step SB2 is adjusted according to the ratio of the thickness TB1 of the material layer 91 in the second material layer formation step SB1 to the thickness TA1 of the material layer 91 in the first material layer formation step SA1. Specifically, if the thickness TA1 of the material layer 91 in the first material layer formation step SA1 is 0.2 mm and the thickness TB1 of the material layer 91 in the second material layer formation step SB1 is 0.15 mm, the ratio of the thickness TB1 of the material layer 91 in the second material layer formation step SB1 to the thickness TA1 of the material layer 91 in the first material layer formation step SA1 is 75%, so the laser light intensity in the second solidification step SB2 is also set to 75% of the laser light intensity in the first solidification step SA2.

As shown in FIG. 6D, by irradiating a predetermined irradiation area of the sixth material layer 91 with laser light L, the sixth material layer 91 is solidified to form a sixth solidified layer 92. Here, the thickness TB2 of the solidified layer 92 formed by the second solidification step SB2 is smaller than the thickness TA2 of the solidified layer 92 formed by the first solidification step SA2.

Next, the second material layer formation process SB1 is performed. After the sixth solidified layer 92 is formed, the recoater head 32 is moved from the left to the right in Figure 6D, and a seventh material layer 91 is formed to cover the sixth solidified layer 92, as shown in Figure 6E.

Next, a second second solidification step SB2 is performed. The laser light intensity used is laser light L with a lower laser light intensity than the previous laser light intensity. Specifically, the second laser light intensity is adjusted according to the ratio of the thickness TB1 of the seventh material layer 91 to the thickness TB1 of the sixth material layer 91. Then, as shown in FIG. 6F, a seventh solidified layer 92 is formed by irradiating a predetermined irradiation area of the seventh material layer 91 with laser light L, as in the first second solidification step SB2.

Furthermore, after the second solidification step SB2, it is determined whether the repetition condition is met (branch SB3 in Figure 4). If the repetition condition is not met, the result is determined to be NO, and the second modeling step SB is repeated.

For example, the number of times the second modeling process SB is repeated may be determined in advance based on the required accuracy of the three-dimensional object to be manufactured and the allowable manufacturing time. Furthermore, for example, the second modeling process SB may be repeated until the error in height between the formed three-dimensional object and the height of the three-dimensional object to be manufactured in each region falls within a predetermined range. Furthermore, for example, the second modeling process SB may be repeated until the distance between the top surface position of the formed three-dimensional object and the lower end positions of the blades 32fb and 32rb of the recoater head 32 falls within a predetermined range.

If the first modeling process SA ends under condition (1) of the preceding paragraph, then theoretically, if the second modeling process SB is repeated an infinite number of times, the lower end positions of the blades 32fb, 32rb will coincide with the upper surface position of the solidified layer 92, and the dimensions will be equal to the dimensions of the three-dimensional object to be manufactured. Even if the first modeling process SA ends under condition (2) of the preceding paragraph, by repeating the process multiple times, the dimensions will be equal to the dimensions of the three-dimensional object to be manufactured. Therefore, it is preferable to repeat the second modeling process SB one or more times.

If the repetition condition is met, the answer is YES, and the manufacturing method according to this embodiment ends. If there are further shapes to be formed, then formation will be carried out again in that area from the first formation process SA.

3. Effects In a manufacturing method using the PBD method, the powder material shrinks during the solidification process, making it difficult to achieve accurate dimensions. In the manufacturing method according to this embodiment, particularly when the first modeling process SA is completed under condition (1), modeling is performed in the second modeling process SB while the base is fixed, allowing dimensions to be measured based on the positions of the blades 32fb and 32rb of the recoater head 32, improving dimensional accuracy. When the first modeling process SA is completed under condition (2), the number of repetitions of the second modeling process SB can be reduced, shortening the manufacturing time and obtaining a three-dimensional model with good dimensional accuracy.
Furthermore, in the manufacturing method according to this embodiment, a three-dimensional object with excellent dimensional accuracy can be obtained at the time when the second modeling process SB is completed. Therefore, compared to a manufacturing method in which an oversized object is formed and then the excess portion is removed later to improve dimensional accuracy, it is possible to reduce costs in terms of time, money, and labor.

In this manufacturing method, the thickness TB1 of the material layer 91 decreases as the second shaping process SB is repeated. That is, the layer that melts and solidifies due to irradiation with the laser light L also becomes smaller, improving the finished surface roughness. Furthermore, because the layer that melts and solidifies due to irradiation with the laser light L becomes smaller, the size of abnormal sintered parts that may occur also becomes smaller, which reduces the load on the machining device 6 during the removal process and makes it possible to extend the tool life. The reduction in the size of abnormal sintered parts that may occur also reduces the risk and number of cutting processes.
For example, when manufacturing a mold, it is preferable to make the surface roughness fine to a certain extent so that even parts that do not become part of the final product, such as excess material, are resistant to dirt. The manufacturing method according to this embodiment makes it possible to obtain a three-dimensional object with fine surface roughness on all of its upper surfaces, eliminating the need for a separate process to compensate for the surface roughness and enabling manufacturing at low cost in terms of time, money, and labor.

DESCRIPTION OF SYMBOLS 1: Chamber 1a: Window 3: Material layer forming device 4: Modeling table 5: Irradiation device 6: Machining device 17: Contamination prevention device 17a: Housing 17b: Opening 17c: Diffusion member 17d: Inert gas supply space 17e: Clean room 31: Base 32: Recoater head 32a: Material storage section 32b: Material supply port 32c: Material discharge port 32fb: Blade 32rb: Blade 33: Recoater head driving device 41: Modeling table driving device 51: Laser light source 53: Focus control unit 55a: X-axis galvanometer mirror 55b: Y-axis galvanometer mirror 90: Base plate 91: Material layer 92: Solidified layer 100: Layer-by-layer modeling device L: Laser light R: Modeling area SA: First modeling process SA1: First material layer forming process SA2 : First solidification step SA3 : Branch SB : Second modeling step SB1 : Second material layer forming step SB2 : Second solidification step SB3 : Branch TA1 : Material layer thickness TA2 : Solidified layer thickness TB1 : Material layer thickness TB2 : Solidified layer thickness

Claims (5)

A method for manufacturing a three-dimensional object, comprising:
The method includes a first molding process and a second molding process,
In the first modeling step, a first material layer forming step and a first solidifying step are repeatedly performed;
In the first material layer forming step, after the modeling table is lowered, material powder is supplied to a modeling region on the modeling table to form a material layer having a predetermined thickness;
In the first solidification step, a predetermined irradiation area of the material layer is irradiated with laser light to form a solidified layer;
In the second modeling step, a second material layer forming step and a second solidifying step are performed;
In the second material layer forming process, the material powder is supplied to the modeling region while the height of the modeling table after the first modeling process is kept fixed, and the material layer having a thickness smaller than the predetermined thickness is formed;
In the second solidification step, the predetermined irradiation area of the material layer is irradiated with laser light to form the solidified layer. The method for manufacturing a three-dimensional object according to claim 1,
The second modeling step is repeated one or more times in this method for manufacturing a three-dimensional object. The method for manufacturing a three-dimensional object according to claim 1 or 2,
A method for manufacturing a three-dimensional object, in which, in the first modeling process, when the solidified layer is formed beyond a position that is lower by the specified thickness than the top surface height position in at least each region of the three-dimensional object to be manufactured, the second modeling process is started. The method for manufacturing a three-dimensional object according to claim 1,
A method for manufacturing a three-dimensional object, wherein the laser light intensity in the second solidification step is lower than the laser light intensity in the first solidification step. The method for manufacturing a three-dimensional object according to claim 1,
In the second material layer formation process, if a protruding abnormal sintered portion is detected in the solidified layer during the formation of the material layer, the formation of the material layer is temporarily stopped, a removal process is performed to remove the abnormal sintered portion, and then the formation of the material layer is resumed.