JP7580952B2 - Method for manufacturing three-dimensional object, three-dimensional modeling device, program, storage medium, and powder deposition device - Google Patents

Description

The present invention relates to a manufacturing method (a method for manufacturing a three-dimensional object) for manufacturing an article by repeatedly forming and solidifying powder layers, such as the so-called powder lamination fusion method, and a three-dimensional modeling device used therein.

In recent years, the development of so-called 3D printers has been actively carried out, and various methods have been attempted. For example, methods such as fusion deposition modeling, stereolithography using photocurable resin, and powder deposition fusion modeling are known.
The powder lamination fusion process is a method for forming a three-dimensional object by repeatedly performing a process of laying raw material powder such as nylon resin, ceramics, metal, etc. in layers and a process of selectively heating and solidifying a part of the powder layer by irradiating it with a laser beam. In recent years, the powder lamination fusion process using metal powder as a raw material has begun to be used as a method for manufacturing articles that require high mechanical strength and good thermal conductivity.

In the powder lamination fusion method, when a laser beam is irradiated to a desired portion of the powder layer according to the shape to be formed to melt and sinter it, a locally protruding solidified portion (protrusion) may be formed due to the influence of the lamination state of the powder layer, the irradiation conditions of the laser beam, etc. In addition, the hot powder may scatter to the surrounding area like sparks, and may adhere to the surface of the solidified portion, forming a protruding solidified portion (protrusion).
If the height of the protrusion becomes greater than the thickness of the next powder layer, the protrusion will interfere with the powder layer forming mechanism when the next layer of powder is deposited and flattened, which can cause the powder layer forming mechanism to get caught on the protrusion and become unable to move, or the product in the middle of being modeled with the protrusion formed thereon to be pushed over and become an obstacle to the powder layer forming mechanism, causing the modeling device to stop operating or making it impossible to lay a uniform powder layer.

To solve this problem, Patent Document 1 discloses a method in which, when the protrusion comes into contact with the powder layer forming mechanism (material supplying means), if the material supplying means receives a force equal to or greater than a preset force, the material supplying means is moved while being temporarily retracted.

JP 2007-100199 A

When the method disclosed in Patent Document 1 is adopted, the material supplying means is temporarily retracted while being moved when it comes into contact with the protrusion, so that it is possible to avoid the modeling device stopping its operation. However, while the material supplying means is being retracted while being moved, the powder material cannot be supplied appropriately. For example, when a powder layer is formed while pushing a pile of powder with a blade, if the blade is retracted at the position of the protrusion, the blade moves with the pile of powder still there. Even if the blade is returned from the retracted position after passing the protrusion, there is a shortage of powder material, so it is not possible to form a powder layer thereafter, or even if it is possible, the layer will be thinner than the specified thickness. This causes a problem of reduced shape accuracy of the three-dimensional model.

As a result, a method has been proposed in which the blade, which was previously made to be highly rigid, is made thinner or constructed using an elastic material, making it possible for the blade to deform when subjected to a force greater than a preset value. This allows the blade to deform and overcome any contact with the protrusions, thereby suppressing fluctuations in the thickness of the powder layer.

However, when a thinner plate or an elastic body is used, the wear resistance and tear strength of the blade decreases, so the blade can wear out or break when repeatedly rubbed against the powder or protrusions when forming the powder layer. If the blade wears out or breaks, it is no longer possible to form a flat powder layer of uniform thickness, which can lead to a decrease in the shape accuracy of the three-dimensional object or the generation of even larger protrusions. This can result in a decrease in the production yield of three-dimensional objects or the necessity to stop the modeling operation midway.

Therefore, when manufacturing a three-dimensional object (article) by repeatedly forming and solidifying a powder layer, there was a need for a method that could prevent a decrease in modeling accuracy or the halt of modeling operations due to wear or damage to the material supply means, and enable the three-dimensional modeling to continue with high accuracy.

According to a first aspect of the present invention, a three-dimensional modeling device includes a modeling table, a thickness-determining member that brings an end of a sheet-like member into contact with a powder and lays a powder layer on the modeling table to determine its thickness, a moving mechanism configured to move the thickness-determining member, a cutting unit that cuts the end, a holding unit that holds the thickness-determining member, an energy beam irradiation unit that irradiates the powder with an energy beam, and a control unit, and the control unit operates the cutting unit to cut the end.

According to a second aspect of the present invention, there is provided a powder deposition apparatus for depositing a powder layer to produce a three-dimensional object, comprising: a sheet-shaped member having an end portion that contacts powder to lay down the powder layer; a cutting section that cuts the end portion; a holding section that holds the sheet-shaped member; and an input section that receives an input signal from the outside, wherein the holding section operates the cutting section in response to the signal input to the input section to cut the end portion.

According to a third aspect of the present invention, there is provided a method for manufacturing a three-dimensional object, comprising: a first powder layer formation process in which a portion of at least one thickness determining member moves while in contact with a powder to form a powder layer; a solidification process in which an energy beam is irradiated to the powder layer formed in the first powder layer formation process to form a solidified portion; a second powder layer formation process performed after the solidification process; and an updating process performed between the first powder layer formation process and the second powder layer formation process, wherein the updating process is a process for changing a portion of the at least one thickness determining member that comes into contact with the powder in the second powder layer formation process to a different portion from the portion in the first powder layer formation process, and the updating process includes a step of cutting the portion that was in contact with the powder when the first powder layer formation process was performed .

According to the present invention, when manufacturing a three-dimensional object (article) by repeatedly forming and solidifying a powder layer, it is possible to prevent a decrease in modeling accuracy or the halt of modeling operations due to wear or damage to the material supply means, and to continue three-dimensional modeling with high accuracy.

FIG. 1 is a schematic diagram showing a configuration of a three-dimensional modeling apparatus according to a first embodiment. FIG. 2 is a perspective view showing a powder deposition apparatus and its surrounding area. FIG. 1 is a partial cross-sectional view showing a schematic structure of a powder deposition apparatus according to a first embodiment. (a) A diagram showing a state in which a sheet-like member is clamped by a fixing portion to fix the position and the height of the lower end portion is regulated. (b) A diagram showing a state in which the blade of the cutting portion is clamped to cut the sheet-like member and cut off the leading end portion. (c) A diagram showing a state in which the roller is rotated to lower the leading end portion to the height of the stacking height regulation line. (d) A diagram showing a state in which the sheet-like member is clamped and fixed by the fixing portion. FIG. 11 is a schematic diagram for explaining a position at which the leading end of a sheet-like member is renewed; 4 is a flowchart for explaining a procedure for forming a three-dimensional object according to the first embodiment. 10 is a flowchart for explaining a procedure for forming a three-dimensional object according to a second embodiment. FIG. 11 is a partial cross-sectional view showing a schematic structure of a powder deposition apparatus according to a third embodiment. 13 is a flowchart for explaining a procedure for forming a three-dimensional object according to a third embodiment. 10 is a flowchart for explaining a procedure for forming a three-dimensional object according to a fourth embodiment. FIG. 13 is a schematic diagram showing the configuration of a three-dimensional modeling apparatus according to a fifth embodiment. FIG. 13 is a partial cross-sectional view showing a schematic structure of a powder deposition apparatus according to a fifth embodiment. FIG. 13 is a partial cross-sectional view showing a schematic structure of a holding portion according to a fifth embodiment. 10A and 10B are diagrams showing an example of a method for adjusting the dimensions of a sheet-like member and controlling the protrusion amount. 5A and 5B are schematic diagrams for explaining the position and operation for replacing the holding portion. 13 is a flowchart for explaining a procedure for forming a three-dimensional object according to a fifth embodiment. 13 is a flowchart for explaining a procedure for forming a three-dimensional object according to a sixth embodiment. FIG. 13 is a partial cross-sectional view showing a schematic structure of a powder deposition apparatus according to a seventh embodiment.

A method for producing a three-dimensional object and a three-dimensional printing apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the drawings referred to in the following description of the embodiment and examples, members having the same functions are denoted by the same reference numerals unless otherwise specified.
In the embodiment of the present invention, the mode of heating the powder layer to form the solidified portion may be such that the heated powder is sintered at a temperature lower than the melting point, or such that the powder is heated to or above the melting point to melt and then cooled to solidify. In the embodiment of the present invention, the solidified portions are stacked to form a three-dimensional object, and although the boundaries between the solidified portions may be confirmed by cross-sectional observation of the three-dimensional object, the boundaries between the solidified portions may not be clearly detected in cases where the melting is highly uniform.

[Embodiment 1]
(3D modeling device)
A three-dimensional modeling apparatus 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram for explaining the configuration of the three-dimensional modeling apparatus 1.
The three-dimensional printing apparatus 1 includes a printing table 101, to which a plate 102 can be attached, which functions as a base when forming a three-dimensional object (article). The printing table 101 includes pins 103 as position references, and the plate 102 is positioned by fitting the pins 103 into pin holes in the plate 102. In this embodiment, the plate 102 is fixed to the printing table 101 by screws 104. Note that the plate does not necessarily have to be plate-shaped as long as it functions as a support base when forming a three-dimensional object, and the method of positioning and fixing the plate to the printing table is not limited to this example. The printing table 101 is supported by a vertical movement mechanism 106 so as to be movable in the vertical direction (positive and negative directions of the Z axis).

On the left and right sides of the modeling table 101, powder storage units 113 for storing raw powder are arranged, and supply raw powder used by the powder deposition device 107 when forming a powder layer on the plate 102. The powder storage unit 113 is supported by the powder storage unit vertical movement mechanism 114 so as to be movable in the vertical direction (positive and negative directions of the Z axis). The powder storage unit 113 is moved a predetermined distance in the positive direction of the Z axis to push up a predetermined amount of raw powder, and the powder deposition device 107 is moved horizontally along the X axis to push the raw powder with the sheet-like member 21, thereby forming a powder layer on the plate 102. The positive direction refers to the direction indicated by the arrow on the coordinate axis shown in the figure, and the negative direction refers to the opposite direction to the arrow shown in the figure. The stacking height control line 201 shown by a dotted line in FIG. 1 indicates the height of the upper surface of the powder layer formed by the powder deposition device 107. The powder storage unit 113 does not necessarily have to be on both the left and right sides of the modeling table as shown in FIG. 1; it can be on only one side, either the left or the right, as long as it has the capacity to store the specified amount of powder required for manufacturing.

A powder deposition device 107 and a moving guide 108 are arranged above the modeling table 101. The powder deposition device 107 is a device for depositing raw material powder to a predetermined thickness, and is supported by the moving guide 108 so that it can move back and forth horizontally along the X-axis to move (scan) on the plate.

Fig. 2 is a perspective view showing the powder deposition apparatus 107 and its surroundings according to this embodiment, and Fig. 3 is a partial cross-sectional view showing the structure of the powder deposition apparatus 107 according to this embodiment.
As shown in FIG. 3, the powder deposition device 107 has a sheet-like member 21, which is wound in a roll shape and rotatably held by a roll support as a holding part 22. The sheet-like member 21 functions as a blade that pushes a pile of material powder in a direction along the X-axis to form a powder layer with a flat upper surface and a constant thickness. Since the thickness of the powder layer formed is determined by the height of the lower end of the sheet-like member 21, the sheet-like member 21 can be said to be a thickness-determining member that determines the thickness of the powder layer. The height of the lower end of the sheet-like member 21 is adjusted to match the stacking height control line 201. When forming the powder layer, the sheet-like member 21 is sandwiched by fixing parts 24 from both sides in the plate thickness direction as shown in FIG. 3 to fix the position, and the height of the lower end is determined.

The sheet-like member 21 has a certain degree of rigidity to determine the thickness of the powder layer, but is formed of a material that allows the contact portion to deform to follow the shape of the protrusion when it comes into contact with a protrusion that is unintentionally formed on the solidified layer, i.e., an elastic material. Specifically, it is formed of an elastic material whose main components are, for example, silicone rubber or elastomer. The sheet-like member 21, which is an elastic member, has sufficient flexibility so that the portion in contact with the protrusion can deform to follow the shape of the protrusion, and has sufficient rigidity so that the surrounding portions that are not in contact with the protrusion are hardly deformed at all. By using such a sheet-like member 21, the flatness of the powder layer laid around the protrusion is maintained even if a protrusion is present.

As described above, the sheet-like member 21 formed from a material flexible enough to deform to follow the shape of the protrusions does not necessarily have high resistance to wear or tearing when scratched. For this reason, repeated friction with the powder and the protrusions can cause wear and tear on the tip of the sheet-like member 21 before the modeling is completed, which can lead to a decrease in modeling quality or make it difficult to continue modeling.

Therefore, the powder deposition device 107 of this embodiment is provided with a mechanism for automatically updating the tip of the sheet-like member 21 before the tip of the sheet-like member 21 is worn out to such an extent that the modeling quality deteriorates or modeling becomes difficult to continue. Here, updating the tip of the sheet-like member 21 means replacing the part of the sheet-like member 21 that was in contact with the powder during the powder layer formation process with a new (unworn) part that was not substantially in contact with the powder. In the description of this embodiment or other embodiments, the part that was not in contact with the powder refers to a part that was not in contact at all, but is not strictly limited to this. For example, a part that was barely worn out even if it was slightly contacted by the flying powder may be interpreted as being included in the part that was not substantially in contact with the powder.
The mechanism for updating (changing) the leading edge includes a cutting unit 25 for cutting the leading edge of the sheet-like member 21 , and a roller 23 (rotating unit) for moving the sheet-like member 21 .

The cutting unit 25 cuts the sheet-like member 21 and is composed of a pair of blades that can be clamped, for example, as shown in FIG. 3. To ensure the flatness of the powder layer, it is necessary to cut the sheet-like member 21 horizontally along a straight line, but if this is possible, the configuration is not limited to a pair of blades. For example, it may be a mechanism that clamps and cuts the sheet-like member 21 between a blade and a plate-like member, or a cutting mechanism such as a wire cutter.

The roller 23, which serves as a moving part having the function of drawing out the sheet-like member, is capable of drawing in the sheet-like member 21 from the roll side toward the downward direction in FIG. 3 by rotating while clamping the sheet-like member 21 from both sides in the plate thickness direction. As will be described later with reference to FIG. 4(c), the height of the lower end of the sheet-like member 21 is adjusted by controlling the amount of rotation of the roller 23. For this reason, the amount of rotation of the roller 23 may be controlled, for example, by a stepping motor or the like, or feedback controlled using an encoder that detects the rotation position.

4(a) to 4(d), the operation of renewing the leading end of the sheet-like member 21, i.e., the renewal process, will be described. Note that in these figures, for convenience of illustration, part of the powder deposition device 107 is omitted.
4(a) shows the state when the powder layer forming process is performed, in which the sheet-like member 21 is sandwiched by the fixing parts 24 from both sides in the plate thickness direction, the position is fixed, and the height of the lower end is regulated. At this time, the rollers 23 also sandwich the sheet-like member 21, but no rotational force is applied to the rollers 23, and they may be fixed by a brake. Also, the blades of the cutting part 25 are retracted to both sides so as not to damage the sheet-like member 21.

Next, in order to renew the tip of the sheet-like member 21, the tip is cut off using the cutting unit 25. That is, as shown in FIG. 4(b), the blade of the cutting unit 25 is clamped to cut the sheet-like member 21 and cut off the tip. At this time, in order to increase the shape accuracy of the cut portion, the cutting is performed with the position of the sheet-like member 21 fixed by the fixing unit 24.

4(c), the blade of the cutting section 25 is retracted to a position where it does not come into contact with the sheet-like member 21, and the fixing section 24 is separated from the sheet-like member 21 to release the sheet-like member 21 so that it can move up and down. Then, the roller 23 is rotated to pull in the sheet-like member 21 from the roll side (not shown), while lowering the new tip portion formed by the cutting to the height of the stacking height control line 20. This moves the new tip portion to a position where it can come into contact with the powder during the next powder layer formation process (moving process). The height of this new tip portion determines the upper surface of the powder layer (thickness of the powder layer), so the amount of rotation of the roller 23 is precisely controlled. In some cases, the height of the tip portion of the sheet-like member 21 may be detected, for example, by an optical sensor and fed back to the drive of the roller 23.

After the height of the leading end of the sheet-like member 21 has been adjusted to match the stacking height regulating line 201, the sheet-like member 21 is clamped and fixed by the fixing portion 24 as shown in FIG. 4(d).
The tip end of the sheet-like member 21 is renewed by the above-described series of operations, and the renewal operation is performed by moving the powder deposition device 107 to a predetermined position within the three-dimensional modeling apparatus 1 .

Figure 5 is a schematic diagram for explaining the position where the operation of updating the tip of the sheet-like member 21 is performed, showing the left side of the three-dimensional modeling device 1, which was omitted in Figure 1. On the opposite side of the modeling table 101 across the powder storage unit 113, an excess powder collection space 121 and a cutting work space 122 are provided. The excess powder collection space 121 is a space for collecting excess powder transported by the powder deposition device 107 when a powder layer formation process is performed to form a powder layer of a predetermined thickness. The collected powder may be discarded or processed for reuse, but if it is free of dust or other contaminants and maintains the same quality as the powder stored in the powder storage unit, it can also be reused as raw powder.

The cutting work space 122 is a space in which the tip of the sheet-like member 21 described with reference to FIG. 4 is renewed. After the powder layer is formed, the powder deposition device 107 is moved above the cutting work space 122 while the powder layer is being irradiated with laser light, and the tip is renewed. The used cut tip is collected in a container in the cutting work space 122.

In this embodiment, the cutting work space 122 is provided with a sensor 130 as an inspection unit for measuring the shape of the tip of the sheet-like material 21. The sensor 130 is a sensor that measures the shape of the tip over the entire width in the Y direction of the sheet-like material 21. For example, it may be an image sensor that can capture an image over the entire width in the Y direction, or a combination of an image sensor that can capture an image of a partial area in the Y direction and a Y direction scanning mechanism. Also, it is not limited to an image sensor, and a distance sensor or ultrasonic sensor may be used.

In this embodiment, after the powder layer is formed, the shape of the tip of the sheet-like member 21 is measured using the sensor 130 while the laser light is being irradiated, and it is determined whether or not the tip needs to be updated. The update operation described with reference to FIG. 4 is performed only if necessary. That is, the image captured by the sensor can be processed by the control unit 112, for example, and the control unit 112 can inspect whether or not deformation due to wear or damage exceeds a predetermined level, and the control unit 112 can perform the update process based on the inspection results. Note that whether or not the tip needs to be updated is not limited to a method based on the shape of the tip of the sheet-like member 21, but can also be performed based on the surface condition of the powder layer.

After performing the tip renewal operation, the shape of the tip of the sheet-like member 21 can be measured using the sensor 130 to confirm whether the renewal operation was performed without any problems. For example, if the shape of the cut portion is irregular due to the accidental presence of dirt between the blade and the sheet-like member 21, this can be detected. This allows the control unit 112 to perform the tip renewal process again before starting the next powder layer formation operation.

Returning to FIG. 1, above the modeling table 101, a laser light source 109, a scanner 110, and a condenser lens 111 are arranged as an irradiation unit that irradiates an energy beam.
The laser light source 109, the scanner 110, and the focusing lens 111 constitute an irradiation optical system for locally and selectively irradiating the powder layer PL laid on the plate 102 by the powder deposition device 107 with a heating energy beam according to the shape to be formed.

The control unit 112 of the three-dimensional modeling apparatus 1 is a computer for controlling the operation of each part of the apparatus, and includes a CPU, a ROM, a RAM, an I/O port, and the like.
The ROM, which is a computer-readable storage medium, stores an operation program for the three-dimensional modeling apparatus 1. For example, the program is a program for the control unit 112 to execute a powder layer formation process in which the powder deposition device 107 serving as a powder layer formation unit is moved to form a powder layer of a predetermined thickness on a base. Alternatively, the program is a program for the control unit 112 to execute a solidification process in which an energy beam is irradiated onto the powder layer PL in accordance with the shape of the three-dimensional object to form a solidified unit 116.
Alternatively, it is a program for the control unit 112 to execute a process of measuring the shape of the tip portion of the sheet-like member 21 using the sensor 130 while the solidification process is being performed, and determining whether or not the tip portion needs to be updated. Alternatively, it is a program for the control unit 112 to execute the tip portion update process described with reference to Fig. 4. Alternatively, it is a program for the control unit 112 to execute a process of measuring the shape of the updated tip portion using the sensor 130 after the tip portion update process is performed.

The I/O port is connected to external devices and networks (not shown), and can input and output data required for three-dimensional modeling between an external computer and the I/O port. Data required for three-dimensional modeling includes shape data of the three-dimensional object to be created, information on the materials used in the creation, and shape data of each sintered layer, i.e., slice data. The slice data may be received from an external computer, or may be created by the CPU in the control unit 112 based on the shape data of the object and stored in the RAM. Alternatively, it may also include reference data for determining whether or not the tip of the sheet-like member 21 needs to be updated.

The control unit 112 is connected to each of the components, such as the modeling table vertical movement mechanism 106, the powder deposition device 107, the laser light source 109, the scanner 110, the condenser lens 111, and the powder storage unit vertical movement mechanism 114, and controls the operations of these components to execute processes related to modeling. That is, the control unit 112 executes a powder layer formation process and a solidification process.
The control unit 112 is also connected to the sensor 130, and controls the operation of the sensor 130, obtains measurement data of the shape of the leading end of the sheet-like member 21 from the sensor 130, and inspects the shape of the leading end.
The control unit 112 also controls the roller 23 , fixing unit 24 , and cutting unit 25 of the powder deposition device 107 to execute a renewal process for renewing the leading end of the sheet-like member 21 .

(Method of manufacturing three-dimensional object)
A method for manufacturing a three-dimensional object using the three-dimensional modeling apparatus 1 will be described.
When the plate 102 is attached to the modeling table 101 of the three-dimensional modeling apparatus 1 , the three-dimensional modeling apparatus 1 repeatedly deposits solidified portions to create a three-dimensional object on the plate 102 .
FIG. 6 is a flowchart for explaining a procedure for forming a three-dimensional object.

When three-dimensional modeling is started, in step S1, the control unit 112 executes a powder layer formation process to form a powder layer of a predetermined thickness. That is, the control unit 112 sends a command to the vertical movement mechanism 106 to move the modeling table 101 to an initial position for performing the modeling operation.
Next, either the left or right powder storage section 113 is raised by the powder storage section vertical movement mechanism 114 to raise the powder above the stack height restriction line 201 .

Next, the control unit 112 sends a command to the powder deposition device 107 to move it from the raised powder storage unit 113 side toward the plate 102 in the positive or negative direction of the X-axis along the movement guide 108. At this time, the position of the sheet-like member 21 in the Z-axis direction is adjusted in advance so that the height of the lower end of the sheet-like member 21 matches the height of the stack height control line 201. The sheet-like member 21 moves over the plate 102 while pushing the powder located above the stack height control line 201, so that a layer of raw powder of a predetermined thickness is formed on the plate 102. That is, the first powder layer formation process is executed.

Once the powder layer is formed, in step S2, the control unit 112 starts the solidification process. That is, the control unit 112 sends commands to the laser light source 109, the scanner 110, and the condenser lens 111 to irradiate the area to be solidified with laser light and heat the raw powder. The laser light emitted from the laser light source 109 is scanned by the scanner 110 in each of the X and Y directions according to the shape to be formed. The laser light is focused by the condenser lens 111 on an extremely narrow area of the powder layer, and the locally heated area is sintered or melted and solidified. By blinking the laser light source 109 while scanning with the scanner 110, the laser light can be irradiated to any position on the powder layer to form the solidified area 116.

After starting the solidification process in step S2, the control unit 112 executes an inspection process in step S3 to inspect the shape of the tip of the sheet-like member 21. That is, the control unit 112 sends a command to the powder deposition device 107 to move it to the measurement position of the sensor 130, and causes the sensor 130 to measure the shape of the sheet-like member 21 and obtain the measurement result. The control unit 112 judges whether there is wear or damage at the tip of the sheet-like member 21 based on the obtained measurement result against a judgment criterion stored in advance. In this case, it is desirable to set the judgment criterion from the viewpoint of preventive safety, not only to detect whether wear or damage has already reached a level that interferes with the formation of the powder layer, but also to detect whether there is a possibility that the wear or damage will reach a level that interferes with the next powder layer formation process, even if it has not yet reached that level.

If it is determined that the leading edge of the sheet-like member 21 is worn or damaged (step S3: YES), the control unit 112 executes steps S4 to S6 to perform a process of updating the leading edge.
First, in step S4, the control unit 112 sends a command to the powder deposition device 107 to move it from the measurement position of the sensor 130 to the cutting work space 122 (FIG. 5).
Next, in step S5, the control unit 112 sends a command to the powder deposition device 107 to cut off the leading end of the sheet-like member 21 as described with reference to FIG. 4(b).

Next, in step S6, the control unit 112 sends a command to the powder deposition device 107 to adjust and fix the height of the tip (lower end) of the sheet-like member 21 as described with reference to Figures 4(c) to 4(d).

Although not shown in the flowchart, after executing the tip updating process, the control unit 112 may execute a process to measure the shape of the updated tip using the sensor 130. If the cut shape is not an appropriate shape, steps S4 to S6 may be executed again.

After completing the tip renewal process by executing steps S4 to S6, in step S7, the control unit 112 judges whether the laser irradiation process started in step S2 has already been completed. If it has not been completed (step S7: NO), step S7 is repeated and the control unit 112 waits for the laser irradiation process to be completed.
Furthermore, if it is determined in the previous step S3 that there is no wear or damage to the tip portion of the sheet-like member 21 (step S3: NO), the control unit 112 proceeds to step S7 and waits for the laser irradiation process to be completed.

If it is determined in step S7 that the laser irradiation process for this powder layer has been completed (step S7: YES), the process proceeds to step S8, in which it is determined whether the molding (solidification) of all layers that make up the three-dimensional object has been completed.
If it is determined that the forming (solidification) of all layers that make up the three-dimensional object has not been completed (step S8: NO), the process returns to step S1 and a powder layer formation process (second powder layer formation process) is performed to form the next solidified layer.
Thereafter, steps S2 and onwards are executed to complete the laser irradiation process. This is repeated until it is determined in step S8 that the shaping (solidification) of all layers constituting the three-dimensional object has been completed.
In step S8, when it is determined that the modeling (solidification) of all layers constituting the three-dimensional object has been completed (step S8: YES), the three-dimensional modeling process is terminated.

According to this embodiment, when manufacturing a three-dimensional object (article) by repeatedly forming and solidifying a powder layer, it is possible to prevent a decrease in modeling accuracy or the halt of modeling operations due to wear or damage to the material supply means, and to continue three-dimensional modeling with high accuracy. As a result, it is possible to continuously manufacture three-dimensional objects with high shape accuracy and with a high yield.

In this embodiment, while the laser light is being irradiated, a sensor is used to measure the change in shape of the tip (bottom end) of the sheet-like member 21, and it is determined whether the tip needs to be renewed (the part in contact with the powder needs to be replaced). Because the measurement is performed in parallel with the irradiation of the laser light during the solidification process, the measurement does not lengthen the process time required to manufacture the three-dimensional object. In addition, because it is determined whether the tip needs to be renewed based on the measurement, cutting (discarding) of the sheet-like member 21 can be kept to a necessary and sufficient extent.

[Embodiment 2]
A second embodiment of the present invention will be described. Descriptions of parts common to the first embodiment will be omitted.
(3D modeling device)
The overall configuration of the three-dimensional printing apparatus of this embodiment is basically the same as that of embodiment 1. However, the manufacturing method of the three-dimensional object, i.e., the control procedure of the three-dimensional printing apparatus, is different, and in this embodiment, the sensor 130 does not measure wear or damage of the sheet-like member 21. For this reason, in this embodiment, it is not necessarily necessary to provide the sensor 130 ( FIG. 5 ) in the three-dimensional printing apparatus. However, the sensor 130 may be provided to perform a measurement process (inspection process) to confirm the shape of the cut portion after cutting the sheet-like member 21.

(Method of manufacturing three-dimensional object)
7 is a flow chart for explaining a procedure for forming a three-dimensional object according to embodiment 2. The same steps as those in embodiment 1 are denoted by the same numbers, and detailed explanations thereof will be omitted.
The powder deposition device of this embodiment also includes a mechanism for automatically replacing the tip of the sheet-like member 21 before the tip of the sheet-like member 21 wears out to the point where the modeling quality deteriorates or modeling becomes difficult to continue. Here, replacing the tip of the sheet-like member 21 means replacing the portion of the sheet-like member 21 that was in contact with the powder when the powder layer was formed with a new (unworn) portion that was not in contact with the powder.

In the first embodiment, after starting the laser light irradiation process in step S2, the shape of the tip of the sheet-like member 21 is inspected in step S3. Then, when it is determined that the tip of the sheet-like member 21 is worn or damaged beyond a predetermined level, a renewal process for the tip is performed.
In contrast to this, in the second embodiment, the timing for executing the tip updating process is stored in the control unit 112 in advance, and the tip updating process is executed when the timing arrives.

Figure 7 is a flow chart for explaining the procedure for forming a three-dimensional object in embodiment 2. After starting the three-dimensional modeling process and executing steps S1 and S2 as in embodiment 1, in step S14, the control unit 112 determines whether it is time to update the tip of the sheet-like member 21. The control unit 112 pre-stores the timing for updating the tip of the sheet-like member 21. The timing for updating the tip can be set, for example, when a predetermined number of layers have been formed, or when the powder layer formation process has been performed a predetermined number of times. In addition, since the larger the area of the solidified layer, the greater the possibility of a protrusion that will damage the tip of the sheet-like member 21 occurring, it can also be set to update the tip every time the integrated area value of the created solidified layer reaches a predetermined size.

If it is determined that it is time to update (S14: YES), steps S4 to S6 similar to those in the first embodiment are carried out to update the leading end of the sheet-like member 21. If it is determined that it is not time to update (S14: NO), the process proceeds to step S7.
According to this embodiment, there is no need to provide a sensor for measuring wear or damage to the sheet-like member 21, so the cost of the three-dimensional modeling apparatus can be reduced.

[Embodiment 3]
A third embodiment of the present invention will be described. Detailed descriptions of parts common to the first embodiment will be omitted.
(3D modeling device)
The overall configuration of the three-dimensional modeling apparatus of this embodiment is basically the same as that of the first embodiment, but the structure of the powder deposition apparatus is different. As described with reference to Fig. 3, the powder deposition apparatus of the first embodiment uses the tip of a sheet-like member as a blade.

In contrast, in the powder deposition device provided in the three-dimensional modeling device of the third embodiment, as shown in FIG. 8, the left and right ends of the sheet-like member 31 are wound into a roll, and each roll is supported by a roll support 32, and the middle part is supported downward by a roller 33. The roller 33 is installed so that the height of the contact surface CS, which is the lowermost part of the sheet-like member 31 stretched by the roll support 32, is the height of the stacking height control line 201. The sheet-like member 31 supported by the roller 33 pushes the pile of material powder in the direction along the X-axis, thereby forming a powder layer with a flat upper surface and a constant thickness. Since the thickness of the powder layer formed is determined by the height of the contact surface CS of the sheet-like member 31 pushing the powder, the sheet-like member 31 can be said to be a thickness determining member that determines the thickness of the powder layer.

When forming the powder layer, the sheet-like member 31 is fixed near the lower circumferential portion of the roller 33, and the same portion of the sheet-like member 31 continues to be in contact with the powder as the contact surface CS.
The sheet-like member 31 has a certain degree of rigidity to determine the thickness of the powder layer, but is made of a material that allows the contact portion to deform according to the shape of the protrusion when it comes into contact with a protrusion unintentionally formed on the three-dimensional model, i.e., an elastic material. In addition, the sheet-like member 31 is formed with a sufficient thickness to be compressively deformable by the height of the protrusion so that the protrusion does not directly damage the roller 33. Specifically, the sheet-like member 31 is made of an elastic material mainly composed of, for example, silicone rubber or elastomer. The sheet-like member 31, which is an elastic member, has flexibility such that the portion in contact with the protrusion deforms according to the shape of the protrusion, and has rigidity such that the surrounding portion not in contact with the protrusion is hardly deformed. By using such a sheet-like member 31, even if a protrusion is present, the flatness of the powder layer laid around the protrusion is maintained.

In this embodiment, a sensor for measuring the shape of the contact surface CS is provided as the inspection unit. The sensor is a sensor that measures the shape of the contact surface CS over the entire width in the Y direction of the sheet-like member 31. For example, it may be an image sensor that can capture an image over the entire width in the Y direction, or a combination of an image sensor that can capture an image of a partial area in the Y direction and a Y direction scanning mechanism. Also, it is not limited to an image sensor, and a distance sensor or ultrasonic sensor may be used.

(Method of manufacturing three-dimensional object)
9 is a flow chart for explaining a procedure for forming a three-dimensional object according to the embodiment 3. The same steps as those in the embodiment 1 are denoted by the same numbers, and detailed explanations thereof will be omitted.
The powder deposition device of this embodiment has a mechanism for automatically updating the contact surface CS of the sheet-like member 31 before the contact surface CS of the sheet-like member 31 is worn to the extent that the modeling quality deteriorates or it becomes difficult to continue modeling. Here, updating the contact surface CS of the sheet-like member 31 means replacing the portion of the sheet-like member 31 that was in contact with the powder when the powder layer was formed with a new (unworn) portion that was not in contact with the powder.

In this embodiment, after starting the laser light irradiation process in step S2, the control unit 112 inspects the shape of the contact surface CS of the sheet-like member 31 in step S3. The control unit 112 judges whether the contact surface CS of the sheet-like member 31 is worn or damaged by checking the acquired measurement results against a previously stored judgment criterion. In this case, it is desirable to set the judgment criterion from the viewpoint of preventive safety, not only to detect whether the wear or damage has already reached a level that interferes with the formation of the powder layer, but also to detect whether the wear or damage has not yet reached a level that may interfere with the next powder layer formation process. Then, if it is determined based on the inspection results that the sheet-like member 31 is worn or damaged (S3: YES), an update process of the contact surface CS is performed (S25).

To update the contact surface CS, the sheet-like member 31, which has been fixed near the lower circumference of the roller 33, is released from its fixation, and the two roll supports 32, which act as moving parts, are linked to rotate the roll. For example, if the roll is rotated clockwise in FIG. 8, the part of the sheet-like member 31 that was in contact with the powder moves to the right, and the part that has not been in contact with the powder moves from the left roll to the lower circumference of the roller 33. As a result, the part that has not been in contact with the powder (the new contact surface CS) is moved to a position where it can come into contact with the powder during the next powder layer formation process, i.e., directly below the roller 33.

The roll support 32 may be driven by any means capable of drawing in and feeding the sheet-like material 31. For example, a method may be used in which the roll support 32 is rotated by a desired angle using a general electric motor that generates a rotational force, such as a stepping motor. Alternatively, a mechanism including an encoder for detecting the rotational position of the roll support 32, or a clutch or brake for stopping the rotation and fixing the position may be used.
After being moved in this manner, the sheet-like member 31 is fixed near the lower circumferential portion of the roller 33, and the renewed portion functions as a new contact surface CS.

According to this embodiment, when manufacturing a three-dimensional object (article) by repeatedly forming and solidifying a powder layer, it is possible to prevent a decrease in modeling accuracy or the halt of modeling operations due to wear or damage to the material supply means, and to continue three-dimensional modeling with high accuracy. As a result, it is possible to continuously manufacture three-dimensional objects with high shape accuracy and with a high yield.

In this embodiment, while the laser light is being irradiated, a sensor is used to measure the change in shape of the contact surface CS of the sheet-like member 31, and it is determined whether or not the contact surface CS needs to be updated (the part in contact with the powder needs to be replaced). Since the measurement is performed in parallel with the irradiation of the laser light, the process time required for manufacturing the three-dimensional object is not extended just because of the measurement. In addition, since it is determined whether or not the contact surface CS needs to be updated based on the measurement, it is possible to suppress the consumption of the sheet-like member 31 to a necessary and sufficient range.
In this embodiment, unlike the first embodiment, cutting of the sheet-like member is not performed, so there is no need to provide a cutting work space 122, and the three-dimensional modeling apparatus can be made smaller in size.

[Embodiment 4]
A fourth embodiment of the present invention will be described. Descriptions of parts common to the third embodiment will be omitted.
(3D modeling device)
The overall configuration of the three-dimensional printing apparatus of this embodiment is basically the same as that of embodiment 3. However, the manufacturing method of the three-dimensional object, i.e., the control procedure of the three-dimensional printing apparatus, is different, and in this embodiment, the wear and damage of the sheet-like member 31 is not measured by a sensor. For this reason, in this embodiment, it is not necessarily necessary to provide a sensor in the three-dimensional printing apparatus. However, a sensor may be provided to perform a measurement process (inspection) to confirm the shape of the contact surface CS after updating the sheet-like member 31.

(Method of manufacturing three-dimensional object)
10 is a flow chart for explaining a procedure for forming a three-dimensional object according to the embodiment 4. The same steps as those in the embodiment 3 are denoted by the same numbers, and detailed explanations thereof will be omitted.
The powder deposition device of this embodiment also includes a mechanism for automatically updating the contact surface CS of the sheet-like member 31 before the contact surface CS of the sheet-like member 31 is worn to the extent that the modeling quality deteriorates or it becomes difficult to continue modeling. Here, updating the contact surface CS of the sheet-like member 31 means replacing the portion of the sheet-like member 31 that was in contact with the powder when the powder layer was formed with a new (unworn) portion that was not in contact with the powder.

In the third embodiment, after starting the laser light irradiation process in step S2, the shape of the contact surface CS of the sheet-like member 31 is inspected in step S3. Then, when it is determined that the sheet-like member 31 is worn or damaged, an update process of the contact surface CS is performed.
In contrast to this, in the fourth embodiment, the timing for executing the update process of the contact surface CS is stored in advance in the control unit 112, and the update process of the tip portion is executed when the timing arrives.

Figure 10 is a flow chart for explaining the procedure for forming a three-dimensional object in embodiment 4. After starting the three-dimensional modeling process and executing steps S1 and S2 in the same manner as in embodiment 3, in step S24, the control unit 112 determines whether it is time to update the contact surface CS of the sheet-like member 31. The control unit 112 pre-stores the timing for updating the contact surface CS of the sheet-like member 31. The timing for updating the contact surface CS can be set, for example, when a predetermined number of layers have been modeled, or when the powder layer formation process has been performed a predetermined number of times. In addition, since the larger the area of the solidified layer, the greater the possibility of the occurrence of protrusions that damage the contact surface CS of the sheet-like member 31, it can also be set to update the contact surface CS every time the integrated area value of the created solidified layer reaches a predetermined size.

If it is determined that it is time to update (S24: YES), step S25 is executed as in the third embodiment to update the contact surface CS of the sheet-like member 31. If it is determined that it is not time to update (S24: NO), the process proceeds to step S7.
According to this embodiment, there is no need to provide a sensor for measuring wear or damage to the sheet-like member 31, so the cost of the three-dimensional modeling apparatus can be reduced.

[Embodiment 5]
(3D modeling device)
A three-dimensional modeling apparatus 1 according to this embodiment will be described with reference to Fig. 11. Fig. 11 is a schematic diagram for explaining the configuration of the three-dimensional modeling apparatus 1. Note that parts common to the first embodiment are indicated with the same reference numerals, and explanations thereof will be omitted. This embodiment differs from the three-dimensional modeling apparatus 1 of the first embodiment shown in Fig. 1 in the structure of the powder deposition device 107.

FIG. 12 is a partial cross-sectional view that shows a schematic structure of a powder deposition apparatus 107 of this embodiment.
12, the powder deposition device 107 has a plurality of holding parts 322 for holding sheet-like members 321, and by successively replacing these, a worn or damaged sheet-like member 321 can be replaced with a new sheet-like member 321. The sheet-like member 321 functions as a blade that pushes the pile of material powder in the direction along the X-axis, forming a powder layer with a flat upper surface and a uniform thickness.

The thickness of the powder layer to be formed is determined by the height of the bottom end of the sheet-like member 321, so the sheet-like member 321 can be said to be a thickness-determining member that determines the thickness of the powder layer. By using an elastic material similar to that of embodiment 1 as the material for the sheet-like member 321, the flatness of the powder layer laid around the protrusions is maintained even if they exist.

However, as explained in the first embodiment, such a sheet-like member 321 does not necessarily have high resistance to wear or tearing when scratched. For this reason, repeated friction with the powder or protrusions may cause wear or damage to the sheet-like member 321 before the modeling is completed, which may result in a decrease in modeling quality or make it difficult to continue modeling.

Therefore, the powder deposition device 107 of this embodiment has a function of switching to another sheet-shaped member before the sheet-shaped member becomes worn to the point where the modeling quality deteriorates or it becomes difficult to continue modeling.
12 , the sheet-like member 321 is held in a sandwiched manner by a holding portion 322, and the holding portion 322 is connected to a connection portion 323. In addition, the connection portion 323 is supported by a linear motion shaft 324, and the linear motion shaft 324 can be moved up and down in the Z direction by a driving source 325.

The driving source 325 may be any type that can move the sheet-like member 321 up and down. For example, a piston mechanism controlled by air pressure or hydraulic pressure, or a mechanism that converts the rotational motion of a motor or the like into linear motion using a rack and pinion may be used.
12 is equipped with five sheet-like members 321, the number of sheet-like members 321 may be any number as long as it is more than one, and is not limited to five. It is sufficient that the powder deposition device 107 has at least a first sheet-like member and a second sheet-like member, and more than five may be equipped.

FIG. 13 is a partial cross-sectional view that illustrates a schematic structure around the holding portion 322 of this embodiment.
13 , the holding portion 322 has a protrusion 326, and the connecting portion 323 has a recess 327. The protrusion 326 and the recess 327 are shaped to be able to fit together, and serve to assemble and fix the holding portion 322 and the connecting portion 323. The recess may be provided on the holding portion 322 side, and the protrusion may be provided on the connecting portion 323 side.
The configuration of the convex portion 326 and the concave portion 327 may be any configuration that allows the holding portion 322 and the connecting portion 323 to be easily assembled, and a fixing method using air pressure, hydraulic pressure, magnetic force, etc. that receives a signal from the control portion 112 and turns the connection ON/OFF may be used.

The holding portion 322 holds the sheet-like member 321 by sandwiching it, and the sheet-like member 321 is fixed to the holding portion 322 by a fixing part 328. The fixing part 328 is configured with a bolt and nut, and applies force in the direction of sandwiching the sheet-like member 321. The sheet-like member 321 and the holding portion 322 are assembled before three-dimensional modeling, and at that time, the protrusion amount 202 of the sheet-like member 321 protruding from the holding portion 322 must be managed with high precision. The precision of the protrusion amount 202 affects the precision of the stacking height control line 201 shown in FIG. 11, and if these precisions are insufficient, good powder stacking cannot be achieved.

14(a) and 14(b) are diagrams showing an example of a method for adjusting the dimensions of the sheet-like member 321 and managing the protrusion amount 202. The method for adjusting the dimensions of the sheet-like member 321 and managing the protrusion amount 202 will be described with reference to Fig. 14(a) and 14(b).
14A, a holding portion 322 that holds a sheet-like member 321 in advance is fixed by using jigs 301 and 302. The jigs 301 and 302 are tools for adjusting the dimensions of the sheet-like member 321.
The jig 301 has a positioning shape 303 that corresponds to the shape of the connection portion 323 of the holding portion 322, and can be used as a reference for dimensional adjustment.

Then, as shown in FIG. 14(b), the sheet-like member 321 is cut to a certain length, i.e., the length of the protrusion amount 202. The jig 302 has a cutting section 304 that cuts the tip of the sheet-like member 321. The cutting section 304 cuts the sheet-like member 321, and is composed of, for example, a pair of clamping blades as shown in FIG. 14(b). To ensure the flatness of the powder layer, it is necessary to cut the sheet-like member 321 horizontally along a straight line, but if this is possible, it is not limited to a configuration using a pair of blades. For example, a mechanism that clamps and cuts the sheet-like member 321 between a blade and a plate-like member may be used, or a cutting mechanism such as a wire cutter may be used.

Figure 15 is a schematic diagram for explaining the position and operation for replacing the holder, showing the left side of the 3D modeling device 1 that was omitted in Figure 11. On the opposite side of the modeling table 101 across the powder storage unit 113, there is a surplus powder collection space 121 and a holder replacement space 422.

The surplus powder collecting space 121 is a space for collecting surplus powder transported by the powder depositing device 107 when a powder layer forming process for forming a powder layer of a predetermined thickness is performed.
The recovered powder may be disposed of or treated for reuse, but if it is free of any foreign matter and maintains the same quality as the powder stored in the powder storage area, it can also be reused as raw powder.

The holding part replacement space 422 is a space for replacing or storing the holding part 322 when all of the sheet-like materials possessed by the powder deposition device 107 are used up during modeling, or when the sheet-like materials are automatically replaced with new ones at the start or end of modeling.
15, in this embodiment, the holder exchange space 422 is provided with a sensor 130 as an inspection unit for measuring the shape of the sheet-like member 321. The sensor 130 is a sensor that measures the shape of the sheet-like member 321 over the entire width in the Y direction. For example, the sensor 130 may be an image sensor capable of capturing an image over the entire width in the Y direction, or a combination of an image sensor capable of capturing an image of a partial area in the Y direction and a Y-direction scanning mechanism. Furthermore, the sensor is not limited to an image sensor, and a distance sensor or an ultrasonic sensor may also be used.

In this embodiment, after the powder layer is formed, the shape of the sheet-like member 321 is measured using the sensor 130 while the laser light is being irradiated, and it is determined whether switching is necessary, and the sheet-like member switching operation is performed only when necessary. That is, the image captured by the sensor can be processed by the control unit 112, for example, and the control unit 112 can inspect whether deformation due to wear or damage exceeds a predetermined level, and the control unit 112 can perform switching processing based on the inspection results. Note that the method of whether switching is necessary is not limited to a method based on the shape of the sheet-like member 321, and can also be based on the surface condition of the powder layer.

After the switching operation, the sensor 130 can be used to measure the shape of the sheet-like member 321 to check whether it has been replaced with a normal sheet-like member and whether the switching operation has been performed without any problems. For example, when cutting the sheet-like member 321 outside the device using the tool shown in FIG. 14(a), if the shape of the cut portion is irregular due to the presence of dirt between the blade and the sheet-like member 321, this can be detected.

When it becomes necessary to switch the sheet-like member, the control unit 112 can switch the sheet-like member before starting the next powder layer formation operation. The replacement operation of the holding unit 322 will be described with reference to Fig. 15 .
As shown in FIG. 15, a holder replacement space 422 is provided on the left side of the three-dimensional modeling device 1, and in this space, a holder that holds a worn sheet-like member is replaced with a holder that holds a fresh sheet-like member.

In the holding part replacement space, a holding table 123 is installed in which the holding part 322 is kept in a fixed position. First, the powder deposition device 107 is moved so that the holding part 322 to be replaced (the holding part that holds the worn sheet-like member) is placed above an empty holding table 123. Then, the powder deposition device 107 is moved up and down to place the holding part 322 on the holding table 123. Next, the connection part 323 is released from the holding part 322, and the worn holding part 322 is left in the holding table 123.

Then, the powder deposition device 107 is moved so that the connection part 323 for replacing the holder is located above the retention table 123 on which the holder 322 for holding the new sheet-like member is retained. Then, the holder for holding the new sheet-like member is attached to the connection part 323 in the reverse order to that used when removing the holder 322 for holding the worn sheet-like member. Note that while FIG. 15 shows an example in which the holder replacement space is provided on the left side of the three-dimensional device, the holder replacement space may be located on either the left or right side, or on both sides.

(Method of manufacturing three-dimensional object)
A method for manufacturing a three-dimensional object using the three-dimensional modeling apparatus 1 of this embodiment will be described.
When the plate 102 is attached to the modeling table 101 of the three-dimensional modeling apparatus 1 , the three-dimensional modeling apparatus 1 repeatedly deposits the solidified portion to create a three-dimensional object on the plate 102 .

FIG. 16 is a flowchart for explaining a procedure for forming a three-dimensional object.
When three-dimensional modeling is started, in step S1, the control unit 112 executes a powder layer formation process to form a powder layer of a predetermined thickness. That is, the control unit 112 sends a command to the vertical movement mechanism 106 to move the modeling table 101 to an initial position for performing the modeling operation.
Next, either the left or right powder storage section 113 is raised by the powder storage section vertical movement mechanism 114 to raise the powder above the stack height restriction line 201 .

Next, the control unit 112 sends a command to the powder deposition device 107 to move it along the moving guide 108 in the positive or negative direction of the X-axis from the raised powder storage unit 113 side toward the plate 102. At that time, the position of the sheet-like member 321 in the Z-axis direction is adjusted in advance so that the height of the lower end of the sheet-like member 321 coincides with the height of the stacking height control line 201.
The powder located above the stacking height regulating line 201 is pushed and moved over the plate 102 by the sheet-like member 21, whereby a layer of raw material powder having a predetermined thickness is formed on the plate 102.

When the powder layer is formed, in step S2, the control unit 112 starts a solidification process. That is, the control unit 112 sends a command to the laser light source 109, the scanner 110, and the condenser lens 111 to irradiate the portion to be solidified with a laser beam and heat the raw material powder.
The laser light emitted from the laser light source 109 is scanned in each of the X and Y directions by the scanner 110 according to the shape to be formed. The laser light is focused by the condenser lens 111 onto an extremely narrow area of the powder layer, and the locally heated portion is sintered or melted and solidified. By blinking the laser light source 109 while scanning with the scanner 110, the laser light can be irradiated to any position on the powder layer to form a solidified portion 116.

After starting the solidification process in step S2, the control unit 112 executes an inspection process in step S3 to inspect the shape of the sheet-like member 321. That is, the control unit 112 sends a command to the powder deposition device 107 to move it to the measurement position of the sensor 130, and causes the sensor 130 to measure the shape of the sheet-like member 321 and obtain the measurement result.
The control unit 112 checks the acquired measurement results against a previously stored judgment criterion to judge whether there is wear or damage to the sheet-like member 321. In this case, it is preferable to set the judgment criterion from the viewpoint of preventive safety, not only for detecting whether the wear or damage has already reached a level that interferes with the formation of the powder layer, but also for detecting whether the wear or damage has not yet reached a level that may interfere with the next powder layer formation process.

When it is determined that the sheet-like member 321 is worn or damaged (step S3: YES), the control unit 112 executes step S34, and executes a process of switching the sheet-like member.
After completing the switching process by executing step S34, in step S7, the control unit 112 determines whether the laser irradiation process started in step S2 has already been completed. If it has not been completed (step S7: NO), step S7 is repeated and the control unit 112 waits for the laser irradiation process to be completed.

Furthermore, if it is determined in the previous step S3 that the sheet-like member 321 is not worn or damaged (step S3: NO), the process proceeds to step S7, where the completion of the laser irradiation process is awaited.
If it is determined in step S7 that the laser irradiation process for this powder layer has been completed (step S7: YES), the process proceeds to step S8, in which it is determined whether the molding (solidification) of all layers that make up the three-dimensional object has been completed.

If it is determined that the shaping (solidification) of all layers constituting the three-dimensional object has not been completed (step S8: NO), the process returns to step S1, and a powder layer forming process is performed to form the next solidified layer. Thereafter, steps S2 and onward are performed to complete the laser irradiation process.
This is repeated until it is determined in step S8 that the forming (solidification) of all layers constituting the three-dimensional object has been completed.
In step S8, when it is determined that the modeling (solidification) of all layers constituting the three-dimensional object has been completed (step S8: YES), the three-dimensional modeling process is terminated.

According to this embodiment, when manufacturing a three-dimensional object (article) by repeatedly forming and solidifying a powder layer, it is possible to prevent a decrease in modeling accuracy or a stop in modeling operation due to wear or damage to the material supply means, and it is possible to continue three-dimensional modeling with high accuracy. As a result, it is possible to continuously manufacture three-dimensional objects with high shape accuracy and with a high yield.
In this embodiment, while the laser light is being irradiated, a sensor is used to measure the change in shape of the sheet-like member 321, and it is determined whether or not the sheet-like member needs to be switched.

[Embodiment 6]
A sixth embodiment of the present invention will be described below. Descriptions of parts common to the first and fifth embodiments will be omitted.

(3D modeling device)
The overall configuration of the three-dimensional printing apparatus of this embodiment is basically the same as that of embodiment 5. However, the manufacturing method of the three-dimensional object, i.e., the control procedure of the three-dimensional printing apparatus, is different, and in this embodiment, a sensor is not used to measure wear or damage to the sheet-like member 321. For this reason, in this embodiment, it is not necessarily necessary to provide a sensor in the three-dimensional printing apparatus.

(Method of manufacturing three-dimensional object)
17 is a flow chart for explaining a procedure for forming a three-dimensional object according to the embodiment 6. The same steps as those in the embodiment 5 are denoted by the same numbers, and detailed explanations thereof will be omitted.
The powder deposition device of this embodiment also includes a mechanism for automatically switching the sheet-like member 321 before the sheet-like member 321 is worn out to the extent that the modeling quality deteriorates or it becomes difficult to continue modeling. Here, switching the sheet-like member 321 means replacing (updating) the sheet-like member 321 that was in contact with the powder when the powder layer was formed with a new (unworn) sheet-like member 321 that was not in contact with the powder.

In the fifth embodiment, after starting the laser light irradiation process in step S2, the shape of the sheet-like member 321 is inspected in step S3. Then, when it is determined that the sheet-like member 321 is worn or damaged beyond a predetermined level, a switching process is performed.
In contrast to this, in the sixth embodiment, the timing for executing the switching process is stored in advance in the control unit 112, and the switching process is executed when the timing arrives.

After starting the three-dimensional modeling process and executing steps S1 and S2 as in embodiment 5, in step S43, the control unit 112 determines whether it is time to switch the sheet-like member 321. The control unit 112 stores in advance the timing for switching the sheet-like member 321. The timing for switching the sheet-like member can be set, for example, when a predetermined number of layers have been formed, or when the powder layer formation process has been performed a predetermined number of times. In addition, since the larger the area of the solidified layer, the greater the possibility of protrusions that will damage the sheet-like member 321 occurring, it can also be set to switch every time the integrated area value of the created solidified layer reaches a predetermined size.

When it is determined that it is time to switch (S43: YES), step S34 similar to that of the fifth embodiment is executed to switch the sheet-like member 321.
On the other hand, if it is determined that it is not the timing to switch (S43: NO), the process proceeds to step S7.
According to this embodiment, there is no need to provide a sensor for measuring wear or damage to the sheet-like member 321, so the cost of the three-dimensional modeling apparatus can be reduced.

[Embodiment 7]
A seventh embodiment of the present invention will be described. Detailed descriptions of parts common to the fifth embodiment will be omitted.

(3D modeling device)
The overall configuration of the three-dimensional modeling apparatus of this embodiment is basically the same as that of embodiment 5, but the structure of the powder deposition apparatus is different. As described with reference to Fig. 12, the powder deposition apparatus of embodiment 5 holds multiple sheet-like members in parallel and performs a switching process by horizontal movement and vertical movement.

In contrast, in the powder deposition device provided in the three-dimensional modeling apparatus of the seventh embodiment, a plurality of sheet-like members 331 are radially arranged and held, as shown in Fig. 18. The sheet-like members 331 are held by being sandwiched between holding parts 332, and the holding parts 332 are connected to connection parts 333.
In this embodiment, unlike the powder deposition device of embodiment 5, the sheet-like members are switched by rotating the radially arranged sheet-like members. The basic configurations of the sheet-like members 331, the holding parts 332, and the connecting parts 333 can be similar to those of embodiment 5, but the method of switching the sheet-like members is different.

The driving mechanism (rotating part) for the rotational operation for switching the sheet-like member 331 may be of any type as long as it is capable of rotating and moving a worn sheet-like member 331 or a fresh, unworn sheet-like member 331 to the switching work position.
For example, a method may be used in which a general electric motor that generates rotational force, such as a stepping motor, is used to rotate the actuator by a desired angle. Alternatively, a mechanism may be used that includes an encoder for detecting the rotational position, or a clutch or brake for stopping the rotation and fixing the position.

In the above, in the first to seventh embodiments, the configuration in which the control unit 112 of the three-dimensional modeling device controls the powder deposition device 107 has been described, but the powder deposition device 107 may be an independent unit having a control unit separate from the control unit 112 of the three-dimensional modeling device. The control unit of the powder deposition device 107 may operate in cooperation with the control unit 112 of the three-dimensional modeling device, or the control unit of the powder deposition device 107 may operate independently of the control unit of the three-dimensional modeling device.

[Example]
Next, specific examples and comparative examples will be shown. Examples 1 to 4 are specific examples according to the above-mentioned embodiment. Comparative example 1 is an example in which modeling was performed using a three-dimensional modeling device equipped with a conventional blade that does not have an automatic renewal function. Examples 1 to 3 used the powder supply mechanism of embodiment 2 of the present invention, and Example 4 used the powder supply mechanism of embodiment 4 of the present invention.

The three-dimensional modeling process in the examples and comparative examples was carried out under the same conditions. In the examples, SUS630 or AlSi10Mg powder materials with a maximum particle size of 35 μm or less and an average particle size of 20 μm were used as raw material powder. In the comparative example 1, the same raw material powder as in the examples 1 to 4 was used for modeling.
A fiber laser was used as the light source, and argon gas with an oxygen concentration of 1000 ppm at a temperature of 30° C. was used as the atmosphere during modeling. The thickness of one layer was 40 μm, and a total of 2500 layers were modeled.

In Examples 1 to 3, which used the powder supply mechanism of embodiment 2, the tip of the sheet-like member was cut and renewed a total of 24 times, every time 100 layers were formed. In Example 4, which used the powder supply mechanism of embodiment 4, the contact surface of the sheet-like member was replaced and renewed a total of 24 times, every time 100 layers were formed.

The three-dimensional object is a 100mm x 100mm x 100mm block to be used as a mechanical device part, and was molded in a single cavity under the same conditions for the example and comparative example. A laser beam with higher energy than that used under typical heating conditions was irradiated to promote powder melting, creating a high-density object with reduced void generation.

These examples and comparative examples were evaluated for two evaluation items: wear of the sheet-like member and the quality of the molded product. Regarding wear of the sheet-like member, the amount of wear of the sheet-like member was evaluated. It was evaluated whether the amount of wear, which is expected to affect the quality of the molded product, was 40 μm or more, which is the lamination thickness of one layer. When the amount of wear was less than 40 μm, it was rated A, and when it was 40 μm or more, it was rated B.

Regarding the quality of the molded product, if a protrusion occurred during the molding process, the appearance of the completed molded product was visually inspected to evaluate whether there were any cracks, unevenness in the molded part, protrusions, etc. due to poor formation of the powder layer. If the appearance was good, it was rated as A, and if cracks, unevenness in the molded part, protrusions, etc. were confirmed, it was rated as B.
Table 1 shows the materials of the sheet-like members, the materials of the powders, and the evaluation results for the examples and comparative examples.

As shown in Table 1, none of the Examples were rated B, which is problematic in practical use. That is, in Examples 1 to 4, the wear of the sheet-like member was small, and the quality of the completed shaped product was good.
In contrast, in Comparative Example 1, the amount of wear of the sheet-like member exceeded 40 μm, which is the thickness of one layer, and this is considered to have affected the molding quality. In addition, since the molded product was completed using the worn sheet-like member, there were shape defects due to insufficient flatness and thickness accuracy of the powder layer, and the shape accuracy of the three-dimensional molded product was low.

[Other embodiments]
The present invention is not limited to the above-described embodiments and examples, and many modifications and combinations are possible within the technical concept of the present invention.
For example, the three-dimensional modeling apparatus need only be provided with a mechanism capable of supplying a thickness defining member that is not consumed in the renewal process, and does not necessarily need to use a rolled sheet-like member or a plate-like elastic member.
In addition, in the above embodiment, a laser light source is used as the light source for heating the laid raw material powder layer, but the light used does not necessarily have to be laser light as long as it is possible to control the irradiation energy density and scan the irradiation light. For example, it is possible to use an irradiation optical system combining optical elements such as a high-intensity lamp, a shutter, a variable-focus lens, and a scanning mirror in some cases. Furthermore, the energy beam irradiation unit for heating does not have to be a device that irradiates a light beam, and may be a device that irradiates, for example, an electron beam.
Furthermore, the raw material powder can be made of a variety of materials, such as metal powder, or resin powder such as ABS or PEEK, and the appropriate particle size can be selected depending on the material.

1...3D modeling device/21...sheet-like member/22...roll support/23...roller/24...fixing section/25...cutting section/31...sheet-like member/32...roll support/33...roller/101...modeling table/102...plate/103...pin/104...screw/106...vertical movement mechanism/107...powder deposition device/108...movement guide/109...laser light source/110...scanner/111...collecting lens/112...control section/113...powder storage section/114...powder storage section vertical movement mechanism/116...solidification section/130...sensor/201...stack height control line/CS...contact surface

Claims (18)

A modeling table and
a thickness determining member for contacting an end of the sheet-like member with a powder to lay a powder layer on the modeling table and determine the thickness of the powder layer;
A moving mechanism configured to move the thickness determining member;
A cutting section that cuts the end portion;
A holding portion that holds the thickness determining member;
an energy beam irradiation unit that irradiates the powder with an energy beam;
A control unit,
The control unit operates the cutting unit to cut the end portion.
A three-dimensional modeling apparatus comprising: the thickness determining member includes a fixing portion that fixes the sheet-like member,
the fixing portion includes a mechanism for adjusting an amount by which the sheet-like member protrudes from the fixing portion,
the control unit controls the mechanism to adjust the amount by which the sheet-like member protrudes from the fixing unit, and then operates the cutting unit.
The three-dimensional modeling apparatus according to claim 1 . The sheet-like member is formed of an elastic material.
3. The three-dimensional modeling apparatus according to claim 1 or 2. The control unit operates the cutting unit during operation of the energy beam irradiation unit.
The three-dimensional modeling apparatus according to any one of claims 1 to 3. The control unit controls the moving mechanism to move the thickness defining member to a predetermined position and operate the cutting unit at the predetermined position.
The three-dimensional modeling apparatus according to any one of claims 1 to 4. a sensor for inspecting the shape of the end portion;
The control unit operates the cutting unit based on an inspection result of the sensor.
The three-dimensional modeling apparatus according to any one of claims 1 to 5. the sensor includes at least one of an image sensor, a distance sensor, and an ultrasonic sensor disposed outside the modeling table;
The three-dimensional modeling apparatus according to claim 6 . the control unit drives the cutting unit in response to any one of the following timings: a timing when a predetermined number of layers have been formed, a timing when the step of laying the powder layer has been performed a predetermined number of times, and a timing when an integrated value of the area of the created solidified layer has reached a predetermined size.
The three-dimensional modeling apparatus according to any one of claims 1 to 5. 1. A powder deposition apparatus for depositing a powder layer for producing a three-dimensional object, comprising:
a sheet-like member having an end portion that contacts the powder to lay the powder layer;
A cutting section that cuts the end portion;
A holding portion that holds the sheet-like member;
An input unit to which a signal is input from an external device,
The holding unit operates the cutting unit in response to a signal input to the input unit to cut the end portion.
1. A powder deposition apparatus comprising: a first powder layer forming process in which a portion of at least one thickness defining member moves while contacting the powder to form a powder layer;
a solidification process for forming a solidified portion by irradiating the powder layer formed in the first powder layer formation process with an energy beam;
a second powder layer forming process carried out after the solidification process;
and an updating process performed between the first powder layer forming process and the second powder layer forming process,
the updating process is a process of changing a portion of the at least one thickness determining member that comes into contact with the powder in the second powder layer forming process to a portion different from the portion in the first powder layer forming process,
The renewal process includes a step of cutting the portion that was in contact with the powder when the first powder layer formation process was performed.
A method for producing a three-dimensional object comprising the steps of: The updating process includes a moving step of moving a portion of the at least one thickness determining member that has not been in contact with the powder in the first powder layer forming process to a position where the portion can be in contact with the powder.
The method for producing a three-dimensional object according to claim 10 . The moving step includes a step of rotating a holding portion that holds the at least one thickness determining member.
The method for producing a three-dimensional object according to claim 11 . The thickness determining member is a sheet-like elastic member.
The method for manufacturing a three-dimensional object according to any one of claims 10 to 12 . The update process is performed during the solidification process.
The method for manufacturing a three-dimensional object according to any one of claims 10 to 13 . The method further includes an inspection step of inspecting, before the renewal process, a shape of the portion of the thickness determining member that has been in contact with the powder when the first powder layer forming process is performed, by a sensor.
The method for manufacturing a three-dimensional object according to any one of claims 10 to 14 . The update process is executed in response to any one of the following timings: a timing when a predetermined number of layers have been formed, a timing when the step of laying the powder layer has been performed a predetermined number of times, and a timing when an integrated value of the area of the created solidified layer has reached a predetermined size.
The method for producing a three-dimensional object according to any one of claims 10 to 15 . A program for causing a computer included in a three-dimensional printing apparatus to execute the first powder layer formation process, the solidification process, the second powder layer formation process, and the update process of the method for manufacturing a three-dimensional object according to claim 10 . A computer-readable storage medium storing the program according to claim 17 .

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