JP2001047520A - Method for lamination shaping - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for lamination shaping which is advantageous for improving the precision of a profile shape of a three-dimensional shaped article. SOLUTION: This method for lamination shaping comprises a spreading process for forming a spread layer 9 and an irradiation process for forming a cured layer by applying light or heat to the spread layer 9. A plurality of the cured layers are laminated by repeating the spreading process and the irradiation process to shape a three-dimensional shaped article. When the spread layer 9 is formed, a first spread material (e.g. resin-coated sand 90) which can be cured by light or heat is spread over a part which becomes the cured layer where the three-dimensional shaped article is formed and at the same time, a second spread material (e.g. normal sand 95) which is not cured even by light or heat or shows lower curing properties than does the first spread material, is spread over a part which is not to be cured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an additive manufacturing method.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. Hei 9-136139 discloses a lamination molding method. This method includes a spraying step of forming a thin scattered layer by spraying the granular material, an irradiation step of curing the scattered layer by irradiating light or heat to form a hardened layer, a spraying step and an irradiation step. This is a technique in which a plurality of cured layers are repeatedly laminated in the thickness direction repeatedly to form a three-dimensional molded object.

In this method, only a portion of the spray layer corresponding to the cross-sectional shape of the three-dimensional structure is cured, and the rest is uncured.

In the above method, the whole of the spray layer is formed by spraying light or heat curable powder. For this reason, a mask corresponding to the cross-sectional pattern of the modeled object is used, and light or heat is irradiated to the scatter layer through the mask. In this case, the portion of the scatter layer that is not covered with the mask is hardened because it is directly irradiated with light or heat. The portion of the spray layer covered with the mask is not cured because it is not irradiated with light or heat.

[0005]

In the above-mentioned method, the whole of the spraying layer is formed of light or heat curable powder. For this reason, in the scatter layer, of the uncured portions, portions directly adjacent to the portions to be cured may unexpectedly cure under the influence of light or heat. These are the effects of light diffraction and heat transmission.

Therefore, the conventional additive manufacturing method is not always satisfactory for improving the accuracy of the contour shape of the hardened layer. Therefore, there is a limit in improving the accuracy of the contour shape of the three-dimensional structure.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an additive manufacturing method which is advantageous for improving the accuracy of the contour of a three-dimensional object.

[0008]

The additive manufacturing method according to the present invention comprises a spraying step of forming a spray layer, an irradiation step of applying a light or heat to the spray layer to form a hardened layer, a spraying step and an irradiation step. In the additive manufacturing method, in which a plurality of cured layers are repeatedly laminated to form a three-dimensional molded object, when forming a scattered layer, the part to be the cured layer forming the three-dimensional molded object can be cured by light or heat. And dispersing a second dispersing material which is not cured by applying light or heat or which has a lower curability than that of the first dispersing material to a portion which is not to be cured. It is.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The first spraying material used in the method of the present invention is one that is cured by light or heat. As a typical first spraying material, a powdery material can be employed. For example, a resin-coated powder can be used.

As the above-mentioned resin, a thermosetting resin can be adopted. For example, sand coated with a thermosetting resin, that is, resin-coated sand can be used. A typical thermosetting resin is phenolic resin. The resin to be coated may be in a solid state, but may be in a liquid state in some cases. It may contain a thermosetting accelerator such as hexamethylene.

The second spraying material is a material which does not cure even when light or heat is applied, or has a lower curing property than the first spraying material. As a typical second spraying material, a powdery material can be employed. For example, ordinary sand particles such as silica sand and zircon sand which are not coated with a resin can be employed.

As light, visible light and invisible light can be adopted.
For example, ultraviolet light can be used as the invisible light. A laser beam can be used as heat. As a laser beam,
A CO ₂ laser beam, a YAG laser beam, or the like having a high energy density can be employed. Further, heat generated by irradiating an infrared lamp to absorb infrared rays can be employed. Infrared rays include far infrared rays, middle infrared rays, and near infrared rays.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

First, the molding apparatus 1 will be described. As shown in FIG. 1, the molding apparatus 1 of the present embodiment
A horizontal lifting frame 11 having rolling rollers 11k and held by the main frame 10 so as to be able to move up and down in the directions of arrows Y1 and Y2, and a plotter 12 held by the lifting frame 11
And a guide 13 provided on the main frame 10, a heat source device 15 movably provided on the guide 13, a frame body 17 having a molding space 17 a, and a lifting body provided movably within the frame body 17. And a drive source 19 for driving the lifting body 18 up and down.

The drive source 19 can be formed by a motor mechanism or a hydraulic cylinder mechanism. The heat source device 15 functions as an irradiation source and heats the scattering layer 9, and includes an infrared lamp 15a for irradiating far infrared rays, and a reflector 15c having a concave surface 15d disposed above the infrared lamp 15a. ing. The reflector 15c directs far infrared rays emitted upward from the infrared lamp 15a downward, that is, the scattering layer 9.
Reflects toward. Since far infrared rays are easily absorbed by the resin, the resin can be thermally cured effectively. In a normal state, as shown in FIG. 1, the heat source device 15 includes a molding frame 17.
Have been evacuated.

The plotter 12 can function as a spraying means, is a self-propelled type having a built-in drive motor 12c, and has a rolling roller 20 driven by the drive motor 12c.
The horizontal direction along the lifting frame 11
It can move along the 1 and X2 directions. The lifting frame 11 can be moved in a direction perpendicular to the plane of FIG. 1 by a rolling roller 11c. Therefore, the plotter 12 held by the lifting frame 11 can also be moved in the direction perpendicular to the plane of FIG. Therefore, the plotter 12 can move in the horizontal two-dimensional direction along the surface of the scatter layer 9 described later. In the lower part of the plotter 12, a discharge port 12a which can approach and face the spray layer 9 is formed.

On the upper part of the main frame 10, a first container 31 containing a resin-coated sand 90 as a first spraying material, and a normal normal sand 95 (not covered with resin) functioning as a second spraying material. For example, a second container 32 containing silica sand) is provided.

The outlet of the first container 31 is connected to the storage chamber of the plotter 12 via the first flexible hose 33. The outlet of the second container 32 is connected to the storage chamber of the plotter 12 via the second flexible hose 34.
When the first on-off valve 35 is opened, the resin-coated sand 90 of the first container 31 is supplied to the plotter 12. When the second on-off valve 36 is opened, the normal sand 95 of the second container 32 is supplied to the plotter 12.

Next, the case of molding will be described. In the spraying step, when the first spraying layer 9 is formed, the elevating body 18 is raised in the direction of the arrow Y1 and set at a predetermined high position, and the resin coated sand 90 or the normal sand is discharged from the discharge port 12a of the plotter 12. 95 is sprayed on the installation surface of the elevating body 18, and the spray layer 9 (average thickness: 0.1 mm) is sprayed.

When spraying the resin-coated sand 90, the first on-off valve 35 is opened, and the normal sand 95 is sprayed from the discharge port 12a of the plotter 12. When spraying the normal sand 95, the second on-off valve 36 is opened, and the normal sand 95 is sprayed from the discharge port 12a of the plotter 12. Therefore, the on-off valves 35 and 36 can function as a spraying means.

In this embodiment, a control device (not shown) for operating the plotter 12 and the lifting frame 11 is provided. The slice data obtained by horizontally slicing the three-dimensional object as the target is created at intervals of 0.1 mm pitch, and the data for driving the plotter 12 at intervals of 0.1 mm, the first opening / closing valve 35 and the second opening / closing are provided. Data for opening and closing the valve 36 is stored in the memory of the control device. The control device controls the travel of the plotter 12 and the opening and closing of the first on-off valve 35 and the second on-off valve 36 based on the data.

The mode of spraying will be described with reference to FIG. FIG. 2 shows a case where a ring-shaped three-dimensional structure is formed. In the frame 17, a ring-shaped region indicated by hatching is a portion MA to be cured. The part surrounded by the ring-shaped part MA is the part MB that is not cured. Further, the ring-shaped portion MA and the inner surface 17c of the frame 17 are formed.
Is a part MB not to be cured.

The spraying is performed at intervals of 0.1 mm from a point P1 near the corner in the frame 17. Point P1 → P2
→ P3 → P4 → P5 → P6 → P7 → P8 → P9 → P10
Since → P11 → P12 is the part MB not to be cured, the normal sand 95 is sprayed.

From the point P12 to the point P13, the resin coated sand 90 is sprayed because the part MA is to be cured.

Point P13 → Point P14 → Point P15 → Point P1
No. 6 is a part MB not to be cured, so that normal sand 95 is sprayed.

From point P16 → point P17 → point P18,
Since the part MA is to be cured, the resin-coated sand 90 is sprayed.

Point P18 → Point P19 → Point P20 → Point P2
Up to 1, normal sand 95 is sprayed because the part MB is not cured.

From point P21 → point P22 → point P23,
Since the part MA is to be cured, the resin-coated sand 90 is sprayed.

Point P23 → Point P24 → Point P25 → Point P2
No. 6 is a part MB not to be cured, so that normal sand 95 is sprayed.

From point P26 → point P27 → point P28,
Since the part MA is to be cured, the resin-coated sand 90 is sprayed.

Thereafter, the resin coated sand 90 is sprayed on the portions MA to be hardened in this manner, and the normal sand 95 is sprayed on the portions MB not hardened, thereby forming the spray layer 9.

After the spraying step is completed and a single spraying layer 9 is formed, an irradiation step is performed. In the irradiation step, as shown in FIG. 3, the plotter 12 is moved up and down in the direction of arrow Y1 together with the lifting frame 11, and the heat source device 15 is moved in the direction of arrow M1 to be set above the scatter layer 9. Then, the scatter layer 9 is irradiated with far infrared rays from the heat source device 15 and heated. As a result, the resin of the resin coated sand 90 sprayed on the portion MA to be cured is thermally cured. Therefore, the adjacent resin-coated sands 90 bond with each other to form a cured layer.

On the other hand, the normal sand 95 sprayed on the portion MB of the spray layer 9 which is not to be hardened is not hardened because it is not hardened by heat.

After the above-described irradiation step is completed, the spraying step is performed again in the same manner as described above to form the next new scattered layer, and the irradiation step is performed on the new scattered layer. Hereinafter, the spraying step and the irradiation step are similarly repeated many times. Thereby, a laminate is obtained. When the laminate is separated from the frame and subjected to a separating treatment as appropriate, the cured layer does not collapse because it is integrated, but the uncured layer collapses easily.
A three-dimensional structure formed by stacking the cured layers is obtained.

As described above, in this embodiment,
In forming the spraying layer 9, a resin-coated sand 90 curable by heat is sprayed on a portion to be a hardened layer forming a three-dimensional structure, and a portion MB that is not hardened is sprayed.
, Normal sand 95 that is not cured by heat is sprayed.
Therefore, even if far infrared rays are irradiated from the infrared lamp 15a of the heat source device 15 to the entire scatter layer 9, the resin-coated sand 90 forms a cured layer, but the normal sand 95 does not form a cured layer.

FIG. 4 shows a boundary area 97 between the scattered portion 90x where the resin-coated sand 90 is scattered and the scattered portion 95x where the normal sand 95 is scattered. FIG.
Shows a mode in which the scattered portion 90x is thermally cured by irradiation with far infrared rays to form a cured layer 90s. Uncured layer 95s
Since the normal sand 95 constituting is not thermally cured even when it receives light or heat, the boundary area 97s between the cured layer 90s and the uncured layer 95s becomes clear as shown in FIG. Therefore, according to this embodiment, it is easy to ensure the accuracy of the contour shape of the cured layer 90s. This is advantageous for improving the accuracy of the contour shape of the three-dimensional structure.

In this embodiment, even if the whole of the scatter layer 9 is irradiated with the infrared lamp 15a in the irradiation step, the normal sand 9 constituting the uncured layer 95s is formed.
5 does not inherently thermoset, so that the cured layer 90s and the uncured layer 95s can be clearly distinguished and formed. Therefore, a costly mask that blocks light and heat for forming the uncured layer 95s can be eliminated, which can contribute to a reduction in manufacturing cost.

FIGS. 6 and 7 show an application example applied to the production of a sand mold for producing a cylinder block casting. FIG. 6 schematically shows a cross section of a part of the cylinder block casting 50. FIG. 7 schematically shows a cross section of a sand mold 52 which is a three-dimensional structure forming this cross section.

In FIG. 7, a region indicated by hatching “x” is a portion MA to be cured, and therefore, a resin-coated sand 90 is sprayed. Other portions are portions MB that are not to be cured, and therefore, normal sand 95 is sprayed.

(Another Embodiment) FIG. 8 shows another embodiment.
As shown in FIG. 8, the plotter 7 includes a first chamber 71 containing a resin-coated sand 90 and a normal sand 95.
, A first passage 73 communicating the first chamber 71 with the discharge port 12a, a second chamber 72 and the discharge port 12a.
, A third on-off valve 75 for opening and closing the first passage 73, and a fourth on-off valve 76 for opening and closing the second passage 74.

When the third on-off valve 75 is opened, the resin-coated sand 90 in the first chamber 71 is discharged from the discharge port 12a and dispersed. When the fourth on-off valve 76 is opened, the normal sand 95 of the second chamber 72 is discharged from the discharge port 12a and dispersed.

FIG. 9 shows another embodiment. As shown in FIG. 9, the plotter 8 includes a first chamber 81 that houses a first resin-coated sand 90 in which a resin is coated on silica sand, a second chamber 82 that houses a normal sand 95, and a resin in a zircon sand. Coated second resin coated sand 9
0, a first chamber 81, and a discharge port 12a.
, The second chamber 82 and the discharge port 12
a, the second passage 85 that communicates with the third chamber 83, and the discharge port 1.
A third passage 86 communicating the second passage 2a, a fifth on-off valve 87 for opening and closing the first passage 84, a sixth on-off valve 88 for opening and closing the second passage 85, and a seventh on-off valve for opening and closing the third passage 86 89.

When the fifth on-off valve 87 is opened, the first resin-coated sand 90 in the first chamber 81 is discharged from the discharge port 12a and dispersed. When the sixth on-off valve 88 opens, the second chamber 82
Is discharged from the discharge port 12a and dispersed. When the seventh on-off valve 89 is opened, the second resin-coated sand 90 in the third chamber 83 is discharged from the discharge port 12a and dispersed.

The second resin-coated sand 90 is formed by coating a resin on a zircon sand having a higher thermal conductivity than silica sand. Therefore, since the second resin-coated sand 90 has a higher thermal conductivity than the first resin-coated sand 90, it is preferable to use the second resin-coated sand 90 in a sand mold portion where it is desired to increase the cooling rate of the casting. Therefore, when casting an iron-based casting, it is preferable to spray the second resin-coated sand 90 on a portion that promotes chilling of the iron-based casting.

In the above-described embodiment, a heating method using far-infrared rays is employed, but heating may be performed by irradiating a laser beam. In this case, a method of scanning and irradiating a laser beam with a reduced beam diameter can be adopted, or a method of irradiating a diffused laser beam with an enlarged beam diameter can also be adopted.

Although not shown, a plotter accommodating resin-coated sand and a plotter accommodating normal sand are separately provided, and an operation of spraying the resin-coated sand from one plotter and an operation of dispersing the resin-coated sand from the other plotter are performed. The operation of spraying the normal sand from the plotter may be performed independently. In this case, the two operations may be performed simultaneously in time, or may be performed staggered in time.

Further, an operation of continuously spraying the resin-coated sand (first spraying material) only on the portion to be cured is performed, and thereafter, the normal sand (second spraying material) is continuously sprayed only on the portion not to be cured. An operation of spraying can also be performed. It can also be reversed.

In addition, the present invention is not limited to the embodiment described above and shown in the drawings, but can be implemented with appropriate modifications as needed without departing from the scope of the invention.

(Supplementary Note) The following technical idea can be understood from the above description. A frame, a dispersing unit that is mounted on the frame so as to be movable in a horizontal two-dimensional direction and forms a spray layer, and a curing source that imparts light or heat to the spray layer to make a desired portion of the spray layer a hard layer. A three-dimensional structure forming apparatus for forming a three-dimensional structure by laminating a hardened layer, wherein the spraying unit applies a first spray material curable by light or heat to a part to be a hardened layer forming the three-dimensional structure. A first spraying means for spraying, and a second spraying means for spraying a second spraying material which does not harden even when light or heat is applied to a portion which is not to be hardened or has a lower hardening property than the first spraying material. An additive manufacturing apparatus characterized by the above-mentioned. According to this apparatus, the method of the present invention can be performed.

[0050]

According to the method of the present invention, in forming a spray layer, a first spray material curable by light or heat is sprayed on a portion to be a hardened layer forming a three-dimensional structure, Uncured or first
A second spraying material having a lower curability than the spraying material is sprayed.
Therefore, the part of the powder that is not cured in the spray layer is
It does not cure or substantially does not cure when exposed to light or heat directly, or indirectly through the diffraction of light or the transfer of heat. Therefore, according to the method of the present invention, the portion not to be cured can be easily disintegrated.

Although the first spray material is cured by light or heat, the second spray material is not cured, so that the boundary between the cured layer and the uncured layer is clear. Therefore, the accuracy of the contour shape of the hardened layer can be improved, which is advantageous in improving the accuracy of the contour shape of the three-dimensional structure.

[Brief description of the drawings]

FIG. 1 is a side view showing, in partial cross section, a state in which a scatter layer is formed by a modeling apparatus.

FIG. 2 is a plan view showing a spraying mode of a spraying layer.

FIG. 3 is a side view showing a state in which a scatter layer is heated by a heat source device in a partial cross section.

FIG. 4 is a cross-sectional view showing a boundary area between a portion where resin-coated sand is sprayed and a portion where normal sand is sprayed.

FIG. 5 is a cross-sectional view showing a boundary region between a cured portion and a non-cured portion.

FIG. 6 is a cross-sectional view schematically showing a cylinder head casting.

FIG. 7 is a plan view showing a spraying mode of a spraying layer.

FIG. 8 is a sectional view of another plotter.

FIG. 9 is a sectional view of another plotter.

[Explanation of symbols]

In the figure, 1 is a modeling device, 12, 7, and 8 are plotters, 15 is a heat source device, and 15a is an infrared lamp.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G03F 7/00 G03F 7/00 (72) Inventor Motoaki Ozaki 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor F-term within the company (reference) 2H096 AA30 CA20 EA02 EA04 4E090 AA10 AB01 BA01 BA02 DA10 HA10 4E092 AA02 AA03 AA45 BA20 4F213 AC01 AD02 AP11 AP12 AR12 AR13 WA25 WA36 WA40 WA86 WA87 WB01 WB11 WE02 WL04 WL12 WL03 WL03 WL03 WL34 WL46 WL74 WL77 WL92 WW33 WW34 4G052 AB23 AB42

Claims (1)

[Claims] 1. A spraying step of forming a spray layer, an irradiation step of applying light or heat to the spray layer to form a hardened layer, and a stacking of the hardened layers by repeating the spraying step and the irradiation step. In the layered molding method for forming a three-dimensional structure, a first scatterable material curable by light or heat is applied to a portion serving as the hardened layer forming the three-dimensional structure when forming the scatter layer. And a second spraying material which does not harden even when light or heat is applied thereto or which has a lower hardening property than the first spraying material, is sprayed on portions not to be hardened.