JPH10211659A - Laminate forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily remove, from a molded substance, an excessive unsolidified or semisolidified substance capable of being solidified remaining in the molded substance, by lamination molding a three-dimensional molded substance into a dividable construction or an exhaust hole retaining construction. SOLUTION: A three-dimensional molded substance 100 is formed with a first cavity 201, a second cavity 202, a third cavity 203, and a fourth cavity 204, and a first unsolidified division boundary area 151 is formed along arrow U2-U2, and then a second unsolidified division boundary area 152 is formed along arrow U3-U3. Accordingly, an upper molded substance 100a and a lower molded substance 100c can be divided by the first division boundary area 151 and second division boundary area 152. By this construction, even in the case of the first cavity 201, second cavity 202, and the third cavity 203 not being communicated with the outside KA or being in insufficient communication, excessive unsolidified resin coating sand HA remaining in these cavities can easily be removed from the molded substance 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an additive manufacturing method for manufacturing a three-dimensional object by irradiating a solidifiable substance having a property of solidifying when irradiated with irradiation energy with irradiation energy.

[0002]

2. Description of the Related Art In recent years, an additive manufacturing technology (Japanese Unexamined Patent Publication No.
No. 530, USP (U.S. Pat. No. 4,247,508)
Is attracting attention. In this additive manufacturing technology, a solidifiable substance such as resin-coated sand is used, and a spraying process of spraying the solidifiable material to form a spray layer, and an irradiation process of irradiating a laser beam to the spray layer to form a thin solidified layer. Are alternately repeated,
Thereby, a large number of solidified layers are sequentially laminated, thereby forming a three-dimensional structure.

[0003] In this layered molding technique, there is obtained an advantage that a molded article having a complicated shape can be accurately molded.

[0004]

However, in the above-described additive manufacturing technology, a portion irradiated with laser light is solidified, but a portion not irradiated with laser light is in an unsolidified or semi-solid state. When using a model,
It is necessary to remove the unsolidified or semi-solidified solidifiable substance from the molded article. However, this removal is not always easy.

[0005] In particular, when the molded article has a cavity not communicating with the outside or insufficient communication, the unsolidified or semi-solidified solidifiable substance remaining in the cavity is molded. It is not easy to remove from objects. This will be described with reference to FIG. In the longitudinal section shown in FIG.
Has a bottom wall portion 101, a side wall portion 102, a ceiling wall portion 103, an upper wall portion 104, a first connecting portion 105, a second connecting portion 106, and a bulging portion 107. The first hollow portion 20 is formed in the modeled object 100.
1, a second cavity 202, a third cavity 203, and a fourth cavity 204 are formed. In the modeled object 100 shown in FIG. 10, the cavities 204 that are still in communication with the outer KA and the cavities 201 to 203 that are not in communication with the outer KA or are not sufficiently communicated remain in these. It is not easy to remove the solidified material in the unsolidified or semi-solidified state from the modeled object 100.

The present invention has been made in view of the above circumstances, and each claim provides an additive manufacturing method that is advantageous for removing an unsolidified or semi-solidified solidifiable substance from a molded article. Is a common task.

[0007]

According to a first aspect of the present invention, there is provided an additive manufacturing method, comprising: using a solidifiable substance having a property of being solidified when irradiated with irradiation energy; A layered molding method for forming a solidified layer, laminating the layers in multiple layers to form a three-dimensional modeled object, characterized in that the modeled object is laminated and formed into a dividable structure or a discharge hole holding structure. .

According to a second aspect of the present invention, there is provided an additive manufacturing method using a solidifiable substance having a property of solidifying when irradiated with irradiation energy and a mask having a transmission pattern, and irradiating the irradiation energy to the solidifiable substance through the mask. By processing, a solidification layer having a shape corresponding to the transmission pattern shape of the mask is formed, and in a layered manufacturing method of forming a three-dimensional structure by laminating the layers in a multilayer, a mask includes a plurality of formed objects. In order to form a divided boundary area that can be divided into individual parts, the apparatus has a mask part for limiting the transmission of irradiation energy in order to form a molded object. Can be divided.

According to a third aspect of the present invention, there is provided an additive manufacturing method using a solidifiable substance having a property of solidifying when irradiated with an irradiation energy and a mask having a transmission pattern, and irradiating the irradiation energy to the solidifiable substance through the mask. By performing the treatment, a solidification layer having a shape corresponding to the transmission pattern shape of the mask is formed, and the mask is unsolidified or semi-solid in a layered molding method in which a three-dimensional molded object is formed by laminating the solidified layers in multiple layers. A discharge hole forming mask portion for restricting transmission of irradiation energy to form a discharge hole for removing a solidifiable substance from the modeled object from the modeled object is provided. A discharge hole is formed in the modeled object by the portion.

According to a fourth aspect of the present invention, there is provided an additive manufacturing method.
Wherein the discharge hole forming mask portion of the mask has a projection shape of a wedge shape or a step shape.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The solidifiable substance used in the method of the present invention solidifies when irradiated with irradiation energy.
The form may be any of powder, granule, liquid, and fluid. Irradiation energy includes visible light range, infrared range,
An invisible light region such as an ultraviolet region can be adopted, and a laser beam is preferable. The infrared light may be far infrared light or near infrared light. As the laser light, for example, a known beam such as a CO ₂ laser, a YAG laser, a ruby laser, an Ar laser, an excimer laser or the like can be appropriately selected, and either a visible laser light or an invisible laser light may be used.

As the irradiation energy, a heater means such as a heating wire may be disposed outside the solidifiable substance, and the irradiation energy from the heater means may be applied to the solidifiable substance. As the solidifiable substance used in the method of the present invention, for example, a powder such as sand coated with a thermosetting resin, a powder formed of a thermosetting resin, a metal powder or the like can be used.
The size of the granular material does not matter.

In the method of the present invention, it is preferable to use a mask when irradiating the irradiation energy. The mask blocks transmission of the irradiation energy and has a transmission pattern through which the irradiation energy is transmitted. The transmission pattern can be formed by an opening, but it is sufficient if the irradiation energy can be transmitted without the opening. For example, since quartz glass has a property of transmitting a YAG laser, a transmission pattern of a mask may be formed by laminating a light-shielding film on quartz glass having no opening.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment will be described below with reference to the drawings. The present embodiment is a case where the present invention is applied to an additive manufacturing technique of solidifying a CO ₂ laser (infrared ray region) by irradiation with a laser beam to obtain a shaped article. (Overall Configuration) FIG. 1 is a conceptual diagram of the overall configuration. In this embodiment, the horizontal two-dimensional direction is defined as an X direction and a Y direction, and the height direction is defined as a Z direction. The X direction and the Y direction are directions orthogonal to each other.

In this embodiment, as can be understood from FIG. 1, a lifting device 2 having a lifting table 1 which can be raised and lowered in the direction of arrow Z, a first driving means 3 for lifting and lowering the lifting table 1,
A dispersing device 5 for receiving resin-coated sand as a solidifiable substance and dispersing the resin-coated sand on the elevating table 1 to form a scatter layer on the elevating table 1;
Drive means 7 for moving in the direction of arrow Y (directions of arrows S1 and S2) along the line, laser oscillator 8 (CO ₂ laser, invisible light) for oscillating laser light, and transmission system 9 for transmitting laser light Rotating mirror device 10 for changing the direction of laser light,
Mask supply table 1 on which many types of masks 12 are stacked
3. A mask collection table 15 on which a large number of used masks 12 are stacked. The mask collection table 15 is used to carry the used masks 12 to the mask collection table 15 and hold the new masks 12 on the mask supply table 13 and arrange them above the elevating table 1. Mask arrangement device 1
With 7.

The mask 12 is made of a steel plate, an aluminum plate, or the like having durability against the laser beam irradiated in this embodiment. The mask 12 has a transmission window 11 functioning as a predetermined transmission pattern through which the laser beam passes.
The transmission window 11 may have a property of transmitting laser light. The mask holder 14 has a function of mounting the mask 12 in a detachable manner. The mask holder 14 moves in the direction of the arrow Y along the guide rail 6 with the mask 12 placed thereon, and with the movement, sets the mask 12 above the elevating table 1 or moves the mask 12 from the elevating table 1. Has a function to keep away.

The mask placement device 17 has a suction unit 17r for magnetically or vacuum-suctioning the masks 12 one by one, and a third drive unit 19 for moving the suction unit 17r. FIG.
When the first driving means 3 is driven, the lifting table 1 of the lifting device 2 moves up and down along the height direction, that is, the directions of the arrows Z1 and Z2, and the height position of the scatter layer stacked on the lifting table 1 is changed. Can be adjusted.

The first driving means 3 is connected via a signal line 3x, and the second driving means 7 is connected via a signal line 7x.
Is controlled by the control device 32 via the signal line 19x. First drive means 3, second drive means 7, third drive means 1
Although a cylinder mechanism such as a hydraulic pressure or a pneumatic pressure can be adopted as 9, a motor mechanism (for example, a stepping motor mechanism) may be used in some cases.

FIG. 2 shows a spray device 5 functioning as a spray layer forming means. As shown in FIG. 2, the spraying apparatus 5 includes a storage container 53 having a storage chamber 51 and discharge ports 52a and 52c,
A cut-out roller 54 rotatably mounted on the bottom of the storage container 53 is provided. The storage chamber 51 is loaded with resin-coated sand HA as a solidifiable substance. The resin-coated sand HA is formed by using a thermosetting resin that is hardened by being hardened by irradiation of a laser beam and solidified, and the thermosetting resin is coated on sand particles. The material of the thermosetting resin is a phenolic resin.

The cutting roller 54 has a large number of cutting grooves 54m arranged in a row along the circumferential direction. The cut-out roller 54 has a horizontal axis shape, and extends in a long axis shape in the arrow X direction as can be understood from FIG. As shown in FIG. 2, the sprinkling device 5 is equipped with a thickness detection sensor 50t functioning as a non-contact type thickness detecting means. The thickness detection sensor 50t is located between the ejection ports 52a and 52c in the directions of the arrows S1 and S2 in which the spraying device 5 moves. The reason is to cope with both the forward movement and the backward movement of the spraying device 5. The thickness detection sensor 50t has a light-emitting portion and a light-receiving portion, emits detection light such as a laser beam for distance detection from the light-emitting portion toward the scattering layer 55, and detects light reflected by the scattering layer 55 by the light-receiving portion. By receiving the light, the distance h between the light emitting unit and the scattering layer 55 is detected.

The height position of the spraying device 5 guided by the guide rail 6 is defined by the guide rail 6. Therefore, even if the spraying device 5 moves in the directions of the arrows S1 and S2,
The height position of the thickness detection sensor 50t is a constant value. Furthermore, in this embodiment, the height position KC of the surface to be sprayed (see FIG. 2)
Is always constant. Therefore, if the distance h is detected, the thickness of the scatter layer 55 is detected in a non-contact manner.

As can be understood from FIG. 2, arrows S1, S
Linear potentiometer 70 functioning as a moving distance detecting means for detecting a moving distance of the spraying device 5 in two directions.
Are arranged. The spraying device 5 is equipped with a detector 50x that slides along the linear potentiometer 70. Thereby, the moving distance of the spraying device 5 is detected.

As can be seen from FIG.
Is moved forward and backward by the second driving means 7 while its height position is defined by the guide rail 6. Therefore, at the time of spraying, the spraying device 5 is maintained in a non-contact state with the spraying layer 55.
Therefore, the guide rail 6 and the second driving means 7 are
Function as a non-contact moving means for moving the spraying device 5 while maintaining the non-contact.

FIG. 3 shows a laser beam irradiation process. The laser light oscillated from the laser oscillator 8 is supplied to a beam expander 9a.
, The beam diameter is enlarged, and reaches the rotating mirror device 10 via the fixed mirrors 9b to 9d. The rotating mirror device 10 has an X rotating mirror 21 which oscillates and oscillates in an arrow XA direction.
It has a galvano scanner 22 and a Y galvano scanner 25 having a Y rotating mirror 24 that swings and vibrates in the YA direction.

When the X rotation mirror 21 vibrates at a predetermined frequency in the direction of the arrow XA, the laser beam vibrates at the frequency in the direction of the arrow X. When the Y rotation mirror 24 swings in one direction of the arrow YA direction, the laser light oscillating in the arrow X direction moves in the Y1 direction of the arrow Y direction. Therefore, the laser oscillator 8, the transmission system 9, and the rotating mirror device 10 constitute a laser irradiation device 20. The control device 32 controls the X-galvano scanner 22 of the rotating mirror device 10 via the signal line 10a and the Y-galvano scanner 25 via the signal line 10b.
To control the output of the laser oscillator 8 via the signal line 8a.

In this embodiment, as can be understood from FIG.
During the irradiation, while the laser light reciprocates a number of times between the irradiation end Ma and the irradiation end Mc in the direction of arrow X and vibrates, the vibrating laser light
Moves once from the irradiation end Ma to the irradiation end Me in the direction of the arrow Y1. As a result, as shown in FIG. 3, a continuous wave irradiation locus is formed by the laser beam. In this embodiment, as can be understood from FIG.
The trajectory is a continuous trajectory of a triangular wave or a quasi-triangular wave in which apexes functioning as irradiation ends Ma and Mc are connected in a substantially triangular shape (laser beam spot diameter: D, scan pitch: P). In this case, it is advantageous to equalize the moving speed in the moving direction of the trajectory of the spot of the laser beam, and it is advantageous to suppress the unevenness of the energy irradiation density in the direction of the arrow X.

Incidentally, it is conceivable to control the laser beam so that the trajectory of the spot of the laser beam is not a triangular wave or a pseudo triangular wave as in this embodiment, but a sine curve. However, in this case, the irradiation energy amount in the vicinity of the laser beam irradiation end in the arrow X direction tends to be higher than that in the other irradiation portions, and therefore, the energy irradiation density may be likely to be uneven in the arrow X direction. is there.

Further, in this embodiment, as shown in FIG. 3, a temperature sensor 30 is provided as temperature detecting means for detecting the temperature of the spray layer 55 sprayed on the elevating table 1. The temperature sensor 30 detects, in a non-contact manner, a region of the scatter layer 55 corresponding to a region that is shielded by the mask 12 and is not irradiated with the laser beam. The detection signal of the temperature sensor 30 is transmitted to the control device 32 via the signal line 30f, and the control device 32 controls the irradiation of the laser beam according to the detection signal of the temperature sensor 30. When a heater is used to irradiate the irradiation energy, the irradiation energy by the heater is controlled according to the detection signal.

In this embodiment, a three-dimensional object is formed by additive manufacturing. In this case, first, a sand scattering process is performed. That is, as can be understood from FIG. 2, the sprinkling device 5 is moved in the direction of the arrow S1 at a constant speed along the mounting surface 1w of the elevating table 1 while rotating the cut-out roller 54 in the direction of the arrow R1. Is spread on the mounting surface 1 w of the lifting table 1. The thickness t of the scatter layer 55 can be appropriately selected according to the type of the shaped object, but is, for example, 0.1 to 0.1.
It can be 4 mm, especially about 0.2 mm, but is not limited to this.

As described above, when the spraying device 5 moves forward in the direction of arrow S1, the thickness detecting sensor 50t irradiates the scattering layer 55 with detection light such as a laser beam for distance measurement at predetermined time intervals.
The distance h between the thickness detection sensor 50t and the scatter layer 55 is detected. As a result, the thickness of the scatter layer 55 is detected.
When the spraying device 5 moves forward in the direction of arrow S1, the detector 50 of the spraying device 5 is moved along the linear potentiometer 70.
x slides, and the moving distance of the spraying device 5 in the direction of the arrow S1 is grasped. Therefore, the distribution of the thickness of the scatter layer 55 in the direction of the arrow S1 in which the scatter device 5 moves is detected.

When the forward movement of the sand spraying process is completed as described above, as can be understood from FIG. 1, the third drive means 19 is driven to perform a mask exchange process, and a new mask 12 is used to cover the upper portion of the spray layer 55. cover. Next, a laser beam irradiation process is performed. In the laser beam irradiation process, as can be understood from FIG. 3, the scattering layer 55 formed on the elevating table 1 is scanned and irradiated with the laser beam M through the mask 12 while the upper surface of the layer is covered with the mask 12. As can be understood from FIG. 3, the scan irradiation is performed over a wider range than the transmission window 11 (size: A × B) of the mask 12.

In the laser beam irradiation process, the irradiated laser beam M passes through the transmission window 11 of the mask 12 and
5 and heat it. The sand portion of the scattered layer 55 irradiated with the laser beam M is thermally cured and solidified, and a thin solidified layer 55A is formed. On the other hand, the portion of the scatter layer 55 which is shielded from light by the mask 12 and is not irradiated with the laser beam M is not solidified without being thermally cured and can be removed.

As described above, the solidified layer 5 having a planar shape corresponding to the planar shape of the transmission window 11 is obtained by the laser beam irradiation process.
5A is formed. After the laser beam irradiation process is completed, the lifting table 1 is lowered in the direction of the arrow Z2 by the amount of the pitch of the descent K. The descending pitch amount K substantially corresponds to the thickness of the scatter layer 55. Therefore, the height position of the spray layer 55 to be newly sprayed becomes constant every time.

Then, in order to return to the sand spraying process, FIG.
As can be understood from FIG.
The solidified layer 55 on the lifting table 1 is rotated in the reverse direction.
The spraying device 5 is moved back in the direction of the arrow S2 along A, whereby the sand is sprayed and a new spraying layer 55 is formed. When the spraying device 5 moves back in the direction of the arrow S2, the thickness detection sensor 50t irradiates the scattering layer 55 with detection light such as a laser beam for distance measurement every predetermined time as described above, and the thickness of the scattering layer 55 is increased. Is detected. When the spraying device 5 moves back in the direction of arrow S2, the detector 50x of the spraying device 5 slides along the linear potentiometer 70, and the moving distance of the spraying device 5 in the direction of arrow S2 is grasped. Therefore, when the spraying device 5 moves back in the direction of the arrow S2, the distribution of the thickness of the spraying layer 55 is detected.

After the return of the sand spraying process as described above, the mask replacement process is performed again as can be understood from FIG. 1, and the upper portion of the spraying layer 55 is covered with a new mask 12. After that, the laser beam is irradiated onto the new scatter layer 55 through the mask 12 in order to execute the laser beam irradiation process again. When such a sand scattering process, a mask exchange process, and a laser beam irradiation process are repeated many times in order, the additive manufacturing proceeds, and a three-dimensional object is formed. FIG. 4 shows the above procedure divided into an overall procedure, a procedure of the spraying device 5, and a thickness detection procedure.

(Principal Configuration) The overall configuration has been described above. Next, the principal configuration will be described with reference to FIGS. FIG. 5 shows a vertical section of the modeled object 100 formed this time. The modeled object 100 is configured by sequentially laminating thin solidified layers in the direction of the arrow Z1. The molded object 100 shown in FIG.
Is of the same type as the model shown in FIG.
01, side wall 102, ceiling wall 103, upper wall 104,
It has a first connecting portion 105, a second connecting portion 106, and a bulging portion 107. A first hollow portion 201, a second hollow portion 202, a third hollow portion 203, and a fourth hollow portion 204 are formed in the modeled object 100. However, this molded article 100 has an unsolidified first
The division boundary area 151 is formed along the line U2-U2 in FIG. Further, an unsolidified second divided boundary area 152 is formed along the line U3-U3 in FIG.

The first divisional boundary area 151 is defined by the arrow U in FIG.
One to several to several tens of solidified layers along 2-U2 can be formed. The second divided boundary region 152 can be formed over one to several to several tens of the solidified layers along the arrow U3-U3 in FIG. A first division boundary area 151,
Since the second divided boundary area 152 is not solidified, it can be peeled. Therefore, as can be understood from FIG. 6, the upper modeled object 1 is formed by the first divided boundary area 151 and the second divided boundary area 152.
00a and the lower molding 100c. When the upper modeled object 100a and the lower modeled object 100c are divided in this way, the first cavity 201, the second cavity 202, and the third cavity 20 that are not communicated with the outer KA or have insufficient communication.
Even in the case of 3, the extra unsolidified resin-coated sand HA remaining in these can be easily removed from the modeled object 100.

At the time of removal, a process of blowing air blow to the resin-coated sand HA and a process of sucking the resin-coated sand HA can be used together. After the removal of the resin-coated sand HA, the divided upper modeled object 100a and the lower modeled object 100c are assembled together to obtain the modeled object 100 again. In this case, the upper model 100a and the lower model 100c may be integrally assembled via a bonding agent such as an adhesive, or the upper model 100a and the lower model 10a may be assembled together.
0c may be housed in a holding frame (not shown) in an assembled state.

FIG. 7 shows a mask 12A used to form a solidified layer along the line U2-U2 of FIG. In the mask 12A, circular openings 303 each forming the bulging portion 107 are formed. Mask 12A
Is formed with a dividing mask portion that blocks a laser hole in order to form a first divided boundary area 151 and a second divided boundary area 152.

When the molded article 100 is a casting mold, the portion becomes a gap after the resin-coated sand HA forming the first divided boundary area 151 and the second divided boundary area 152 is removed. Therefore, it can be used as a gas vent hole. (Second Embodiment) A second embodiment shown in FIGS.
The configuration is the same as that of the above-described first embodiment, and basically has the same operation and effect as the first embodiment. The following description focuses on the differences.

The molded object 100 shown in FIG.
And has a bottom wall portion 101, a side wall portion 102, a ceiling wall portion 103, an upper wall portion 104, a first connecting portion 105, a second connecting portion 106, and a bulging portion 107. A first hollow portion 201, a second hollow portion 202, a third hollow portion 203, and a fourth hollow portion 204 are formed in the modeled object 100.

However, this molded article 100 has a semi-solid first division boundary area 161 in which a solid state and a non-solid state are mixed.
A second division boundary area 162 is formed. The first divided boundary area 161 can be formed over one to several to several tens of the solidified layers along the arrows U4-U4 in FIG. Second
The division boundary area 162 can be formed over one to several to several tens of the solidified layers along the arrows U5 to U5 in FIG.

An external force having a predetermined magnitude is applied to the first divided boundary area 16.
If the first and second divisional boundaries 162 are added to the first and second divisional boundary regions 162, the first and second divisional boundary regions 161 and 162 are separated, so that the modeled object 100 is divided into the upper modeled object 100a and the lower modeled object 100c. At the time of removal, the above-described air blow processing or suction processing can be used together. After removal, the upper molded article 100a
And the lower molded article 100c are integrally assembled.

As described above, the upper model 100a and the lower model 1
00c, the first that is not in communication with the outer KA
Even in the hollow portion 201, the second hollow portion 202, and the third hollow portion 203, the unsolidified resin-coated sand HA remaining there.
Can be easily removed. FIG. 8B shows a mask 12B used for solidifying the solidified layer along the line U4-U4 in FIG. 8A. A circular opening 303 for forming the bulging portion 107 is formed in the mask 12B. Further, a net 309 functioning as a mask for dividing a modeled object is provided in the opening 306. Net 309
Is a mesh material having a mesh. Instead of the mesh body 309, a plate member having a large number of through holes through which the laser beam passes can be adopted.

In the area of the above-mentioned scatter layer 55 facing the net 309, the laser light is considerably shielded by the net 309, so that the thermosetting of the resin-coated sand HA becomes insufficient,
The first division boundary region 161 is in a semi-solid state. By the same operation, the second divided boundary region 162 in a semi-solid state is formed on the modeled object 100. By the way, the first divided boundary area 161 and the second divided boundary area 162 are in a semi-solid state in which solidification and non-solidification are mixed, and therefore, compared to a case where they are completely unsolidified.
The peel resistance is improved. Therefore, unless an external force of a predetermined magnitude is applied to the first divided boundary area 161 and the second divided boundary area 162, they do not separate. Therefore, it is also advantageous in suppressing the problem that peeling is easily caused during additive manufacturing.

(Third Embodiment) The second embodiment shown in FIGS. 9A and 9B has the same configuration as that of the first embodiment.
Basically, the same operation and effect as those of the first embodiment can be obtained. The following description focuses on the differences. FIG. 9A shows a cross section of a three-dimensional structure 500. Sculpture 500
Has an outer mold part 501, a core 502, and a hollow part 503.
Further, a first wedge-shaped discharge hole 505 having a narrow inner side,
Similarly, a stepped second discharge hole 506 having a narrow inside is formed in the modeled object 500.

The first discharge hole 505 and the second discharge hole 506 are
The cavity 503 is formed so as to communicate with the outer KA. Therefore, the unhardened resin-coated sand HA remaining in the hollow portion 503 can be discharged to the outside KA through the first discharge hole 505 and the second discharge hole 506. At this time, the first discharge holes 50
5. It is preferable to adopt a process of blowing air blow into the second discharge hole 506 or a process of sucking from the first discharge hole 505 and the second discharge hole 506.

FIG. 9 (B) shows the shaped object 5 shown in FIG. 9 (A).
10 shows a mask 12D for forming a solidified layer of No. 00. A first mask portion 605 and a second mask portion 606 functioning as a discharge hole forming mask portion are formed on the mask 12D. The first mask portion 605 forms a wedge-shaped first discharge hole 505 having a narrow inner side. The second mask portion 606 has a stepped shape with a narrow inside, and forms a stepped second discharge hole 506.

The first mask section 605 and the second mask section 606
Is made of a metal that does not transmit laser light (for example, aluminum foil, aluminum tape, iron plate, etc.). First mask section 60
5. The second mask portion 606 may be formed in the mask 12D in advance, or may be formed by post-processing. The first mask portion 605 and the second mask portion 606 can be provided on the mask 12D that forms several to several tens of the objects 500 in the height direction.

When the molded article is used as a mold,
The first discharge hole 505 and the second discharge hole 506 can also be used as vent holes for discharging gas during casting. Even when the molten metal enters the first discharge hole 505 and the second discharge hole 506 and solidifies, the molten solidified portion has a wedge shape and a stepped shape, which is advantageous for breaking the molten solidified portion. is there. Further, as can be understood from FIG. 9A, separate plugs 515 and 51 are provided in the first discharge hole 505 and the second discharge hole 506.
6, the molten metal may be leaked. The plug 515 preferably has a congruent shape with the first discharge hole 505, and the plug 516 preferably has a congruent shape with the second discharge hole 506.

(Other Examples) In the first and second embodiments, a method is adopted in which the object can be divided, and in the third embodiment, a method in which a discharge hole is formed in the object is employed. Further, a method of dividing the modeled object and a method of forming a discharge hole in the modeled object may be used in combination.

In each of the above embodiments, the dividing boundary area 151,
In forming the 152, 161 and 162 and the discharge holes 505 and 506 in the modeled object, the laser beam blocking action by the mask is used, but the present invention is not limited to this, and the CAD data relating to the laser irradiation input to the control device 32 is changed. By doing so, it is also possible to adopt a method in which scanning irradiation is performed so as not to irradiate laser light to areas corresponding to the division boundary areas 151, 152, 161, 162, and the discharge holes 505, 506.

[0053]

According to the additive manufacturing method of the first aspect,
Laminate the formed object into a divisible structure or a discharge hole holding structure. Therefore, if the object is divided or the discharge hole is used, the unsolidified or semi-solidified excess solidifiable substance remaining in the object can be easily removed from the object.

According to the additive manufacturing method according to the second aspect, at the time of additive manufacturing, a division boundary area is formed on the molded article by the mask portion for dividing the molded article of the mask, and the molded article can be divided by the division boundary area. I do. By dividing the shaped article in this way, the unsolidified or semi-solidified excess solidifiable substance remaining in the shaped article can be easily removed from the shaped article. According to the additive manufacturing method according to the third aspect, at the time of additive manufacturing, the discharge hole is formed in the modeled object by the discharge hole forming mask portion. Unsolidified or semi-solidified excess solidifiable material remaining in the object can be easily removed from the object through the discharge hole. Further, in forming the mask portion for forming the discharge hole in the mask, the mask can be formed simply by sticking an aluminum foil or the like to a desired position on a conventionally used mask, and the operation is simple.

According to the additive manufacturing method of the fourth aspect, the mask portion for forming the discharge hole of the mask has a wedge-shaped or step-shaped projection form. Therefore, when the molded article is used as a mold, even when the molten metal enters the discharge hole and solidifies, the molten solidified portion has a wedge shape and a stepped shape, so that the molten metal solidified portion is broken. It is advantageous for

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing the entire configuration.

FIG. 2 is a configuration diagram showing a sand spraying process.

FIG. 3 is a configuration diagram schematically showing a form in which scanning irradiation is performed by a rotating mirror device.

FIG. 4 is a configuration diagram illustrating a procedure of processing.

FIG. 5 is a vertical cross-sectional view showing a molded article in which resin-coated sand remains.

FIG. 6 is a vertical cross-sectional view showing a state where a molded object in which resin-coated sand remains is divided.

FIG. 7 is a plan view of a mask for forming a solidified layer along the line U2-U2 in FIG. 5;

FIG. 8A is a longitudinal sectional view showing a molded article in which resin-coated sand remains, and FIG. 8B is a mask for forming a solidified layer along the line U4-U4 in FIG. It is a top view.

FIG. 9A is a cross-sectional view of a model at a predetermined height position, and FIG. 9B is a plan view of a mask for forming a solidified layer thereof.

FIG. 10 is a vertical cross-sectional view showing a molded article in which resin-coated sand remains according to the related art.

[Explanation of symbols]

In the figure, 1 is a lifting table, 8 is a laser oscillator, 10 is a rotating mirror device, 11 is a transmission window, 12 is a mask, 17 is a mask arrangement device, 55 is a scatter layer, 55A is a solidified layer, and 151 is a solidified layer.
Is a first division boundary area, 152 is a second division boundary area, 161 is a first division boundary area, 162 is a second division boundary area, 309 is a mesh body (a mask portion for dividing a structure), and 505 is a first discharge hole. , 5
06 denotes a second discharge hole, 605 denotes a first mask portion (a discharge hole forming mask portion), and 606 denotes a second mask portion (a discharge hole forming mask portion).

Claims (4)

[Claims] 1. A solidified layer is formed by using a solidifiable substance having a property of solidifying when irradiated with irradiation energy, and irradiating the irradiation energy to the solidifiable substance to form a solidified layer. An additive manufacturing method for modeling a three-dimensional object, wherein the object is additively formed into a divisible structure or a discharge hole holding structure. 2. A method according to claim 1, further comprising using a solidifiable substance having a property of solidifying when irradiated with irradiation energy and a mask having a transmission pattern, and irradiating the solidifiable substance with the irradiation energy through the mask. Forming a solidified layer having a shape corresponding to the transmission pattern shape, and laminating the solidified layers to form a three-dimensional modeled object, wherein the mask is capable of dividing the modeled object into a plurality of pieces. A mask for dividing a shaped object that limits the transmission of irradiation energy to form a divided boundary area on the modeled object to be formed.When the layered modeling is performed, the masked object for dividing the modeled object is used to mask the modeled object. An additive manufacturing method characterized in that it can be divided. 3. A mask comprising a solidifiable substance having a property of solidifying when irradiated with irradiation energy and a mask having a transmission pattern, and irradiating the solidifiable substance with the irradiation energy through the mask. Forming a solidified layer having a shape corresponding to the transmission pattern shape, and laminating the solidified layer to form a three-dimensional modeled object, wherein the mask is an unsolidified or semi-solidified solidifiable substance. A discharge hole forming mask for restricting the transmission of irradiation energy to form a discharge hole for removing the molding from the modeled object. An additive manufacturing method, wherein the discharge hole is formed in an object. 4. The additive manufacturing method according to claim 3, wherein the mask portion for forming the discharge hole of the mask has a projection shape of a wedge shape or a step shape.