JP7644693B2 - Mold, manufacturing method thereof and casting method - Google Patents

Description

The present invention relates to a mold that is made using shaping sand by an additive manufacturing device and is used to cast a component having a wing portion that protrudes in a direction different from the central axis, as well as a manufacturing method and a casting method for the mold.

In recent years, molds made with additive 3D printers have become popular. Generally, molds are made by transferring a wooden or metal pattern to the original, but such molds always require a process called demolding, and the wooden or metal pattern must be shaped so that it can be removed.

In contrast, molds made with an additive 3D printer are made by laying out a certain thickness of sand, hardening only the necessary parts, and stacking them in order, so there is no need to perform the process of demolding. Therefore, even molds with shapes that have a reverse slope, for example, can be easily made.

Among molds, propellers, screws, impellers, and other components with blades that protrude in a direction different from the central axis often have complex shapes and are often produced in sections. The more sections there are, the lower the dimensional accuracy becomes, which can lead to reduced performance. However, with additive 3D printers, there are no restrictions on shape and there is no need to divide even complex shapes, so additive 3D printers are increasingly being used to produce components with blades.

For example, the part shown in Figure 6 can be produced using the mold shown in Figures 7A and B, which is produced using a layered 3D printer. The mold shown in Figures 7A and B has a cylindrical outer shape, but in order to reduce the modeling time of the 3D printer and to reduce wasteful consumption of materials, it is preferable to use a mold with a constant wall thickness that follows the shape of the casting, as shown in Figures 8A and B.

The manufacture of components with blades is often performed using lost-wax casting, but this requires the production of a wax mold for the casting, which is very time-consuming (see Patent Documents 1 and 2). In addition, lost-wax casting is not suitable for producing large castings, and the types of castings that can be produced are limited.

Japanese Patent Application Publication No. 07-16701 JP 2003-94148 A JP 2003-275846 A

As mentioned above, molds made with an additive 3D printer are not limited in shape and can be made into even complex shapes, making them suitable for making molds for components with winged parts. However, with additive 3D printer molds, it is necessary to remove the unhardened sand remaining in the hollow structure after modeling is complete. If unhardened sand remains, there is a risk that the desired shape will not be obtained when casting.

It is desirable to remove unhardened sand while visually checking that no sand remains, but in a casting mold for a component with a blade portion as shown in Figure 6, it is difficult to visually check whether or not sand remains in the hollow blade forming portion used to cast the blade portion. Therefore, unhardened sand is likely to remain in the blade forming portion.

In the invention described in Patent Document 3, a vent is provided in the hollow structure, and unhardened sand is removed through the vent. However, since the invention described in Patent Document 3 aims to save material used in the mold, the hollow structure in which the vent is provided is a hollow structure provided to save material, and molten metal is not poured into it. Therefore, it is not a problem if some unhardened sand remains in the hollow structure, and no consideration is given to the remaining unhardened sand.

The present invention was made in consideration of these circumstances, and aims to provide a mold that can prevent unhardened sand from remaining in the hollow blade forming section used to cast the blade section, as well as a manufacturing method and casting method for the mold.

(1) In order to achieve the above object, the mold of the present invention is a mold that is produced by an additive manufacturing device using shaping sand and is capable of casting a member having a blade portion that protrudes in a direction different from a central axis, and is characterized in that it has a hollow blade forming portion used for casting the blade portion, a main body portion having an opening formed on at least one main surface of the blade forming portion, and a lid portion that covers the opening.

In this way, the blade forming section has a main body with an opening formed on at least one of its main surfaces, and a lid that covers the opening, so that unhardened sand can be removed while checking the remaining sand, preventing unhardened sand from remaining in the blade forming section.

(2) In addition, in the casting mold of the present invention, the main body further has a shaft forming portion that is used for casting a shaft portion that is provided along the central axis, and the opening is formed in a portion excluding a predetermined area on the root side of the blade forming portion. This prevents design errors from occurring around the root of the blade forming portion.

(3) In addition, in the casting mold of the present invention, the opening is formed in a portion excluding a predetermined area on the central axis side. This prevents errors from occurring on the central axis side due to design errors.

(4) The mold of the present invention is also characterized in that it has a positioning structure that fixes the position of the lid portion relative to the body portion. This makes it possible to position the lid portion in an appropriate position and prevents burrs from occurring.

(5) In addition, in the mold of the present invention, the positioning structure is characterized in that the inner side of the positioning structure is a claw portion that contacts the outer surface of the blade forming portion. This makes it easy to position the lid portion in the appropriate position and suppresses the occurrence of burrs.

(6) In addition, in the casting mold of the present invention, the main body has a plurality of the vane forming sections, and the opening is formed in each of the vane forming sections. This makes it possible to remove unhardened sand from each vane forming section while checking the remaining sand, thereby preventing unhardened sand from remaining in the vane forming sections.

(7) In addition, in the casting mold of the present invention, the blade forming portion has a hollow that forms the blade portion in a spiral shape, and is characterized in that a plurality of the openings are formed. As a result, even in the blade forming portion having a hollow that continues in a spiral shape, it is possible to remove unhardened sand while checking the remaining sand, and it is possible to prevent unhardened sand from remaining in the blade forming portion.

(8) The mold manufacturing method of the present invention is a mold manufacturing method according to any one of (1) to (7) above, characterized in that the molded body is formed using an additive manufacturing device by repeating a series of steps including a step of spreading the molding sand evenly to a certain thickness and a step of injecting a binder into a predetermined portion that will become the mold as a molded body and hardening the binder.

This makes it easier to remove unhardened molding sand from the opening of the molded body. In addition, high dimensional accuracy can be maintained even for molds with complex shapes without having to divide them into multiple parts. Furthermore, improved dimensional accuracy of the mold can improve the performance of the casting itself produced by the mold.

(9) The casting method using the mold of the present invention is a casting method using the mold described in any one of (1) to (7) above, characterized in that it includes the steps of sealing the opening with the lid, placing the mold with the opening covered by the lid inside a molding flask, filling the flask with molding sand so as to fix the mold, pouring molten metal into the mold, and removing the casting produced in the mold.

This makes it difficult for unhardened sand to remain in the blade forming area, which makes it difficult for defects to occur in the casting. Also, by sealing the opening with the lid during casting, a casting of the desired shape can be produced.

According to the present invention, in the hollow blade forming section used for casting the blade section, it is possible to remove unhardened sand while checking the remaining sand, thereby preventing unhardened sand from remaining in the blade forming section.

FIG. 2 is an exploded perspective view showing a schematic configuration of a mold according to the first embodiment. FIG. 2 is a perspective view showing a state in which a lid is installed to cover an opening in the mold according to the first embodiment. FIG. 13 is a diagram showing a modified example of the positioning structure, and is a partial cross-sectional view showing the periphery of the opening of the main body portion. FIG. 11 is a perspective view showing a schematic configuration of a main body and a lid according to a second embodiment. FIG. 11 is a perspective view showing a modified example of the main body portion according to the second embodiment. FIG. 2 is a perspective view showing a schematic configuration of a casting. FIG. 1 is a perspective view showing a schematic configuration of a conventional mold. FIG. 7B is a cross-sectional view taken through the central axis of the mold shown in FIG. 7A. FIG. 1 is a perspective view showing a schematic configuration of a conventional mold. FIG. 8B is a cross-sectional view taken through the central axis of the mold shown in FIG. 8A.

[First embodiment]
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. Note that in each embodiment, differences from the basic embodiment will be mainly described, and descriptions of similar configurations will be omitted.

Figure 1 is a perspective view showing a mold 1 according to a first embodiment of the present invention. The mold 1 is formed from shaping sand and a binder, and has a hollow structure. The shaping sand is sand used to shape molds using a 3D printer (additive manufacturing device). The binder bonds the particles of the shaping sand together and hardens. Note that if the shaping sand is sintered with a laser, the binder is not necessary.

The mold 1 of the present invention can cast a component having a wing portion that protrudes in a direction different from the central axis. The mold 1 shown in FIG. 1 is composed of a main body portion 100 and a lid portion 200. The main body portion 100 has a hollow structure realized by a wall portion 110 formed from molding sand and a binder. The hollow structure refers to a structure made of a wall portion and a hollow portion, and the hollow portion refers to the space itself surrounded by the wall portion (excluding the wall portion).

The wall portion 110 is provided with an inlet 120 for pouring molten metal. The size of the inlet 120 is not particularly limited and is set appropriately according to the shape of the mold 1 to be produced. The inlet 120 only needs to be formed in a position that makes it easy to pour the molten metal, and is preferably formed in a position that will be the upper end during casting.

The thickness of the wall 110 of the mold 1 is preferably 2 mm or more and 12 mm or less. Having a thickness of 12 mm or less ensures sufficient breathability and reduces costs. If the thickness of the wall 110 is less than 2 mm, the risk of breakage increases when handling the mold 1, so the practical lower limit is 2 mm. It is even more preferable that the thickness of the wall 110 is 5 mm or more. Having a thickness of 5 mm or more for the wall 110 reduces the risk of breakage as a mold and maintains sufficient strength.

The wall portion 110 also has a hollow shaft forming portion 111 used for casting the shaft portion, and a hollow blade forming portion 112 used for casting the blade portion. The mold 1 shown in FIG. 1 has three blade forming portions 112. The shaft forming portions 111 and the blade forming portions 112 are connected by their respective hollow structures to form a single hollow structure.

The blade forming part 112 has an opening 130 on the main surface that is the upper surface. In this case, "upper" refers to the vertically upper side in the arrangement at the time of casting, and "main surface" refers to the largest surface of the surfaces of the blade forming part 112. The opening 130 is preferably formed in a part excluding a predetermined area on the base side of the blade forming part 112. If the opening 130 is formed up to the base of the blade forming part 112, there is a high risk that an error in the meshing when the lid part 200 is closed will remain in the casting. For castings such as screws, the accuracy of the base of the blade is functionally important, and it is preferable that the mold for this part is integrated so that no deviation in accuracy remains.

In this way, the specified area is the base area that must be formed without error. Providing the specified area makes it easier to process burrs that occur between the opening and the lid during casting. In particular, providing the specified area that is at least 1/4 of the radial width of the blade forming part makes it easier to perform known burr processing, such as removing burrs along the surface with a tool such as a grinder.

The opening 130 is preferably formed so that the remaining sand can be confirmed in all areas of the blade forming portion. Therefore, the opening 130 is preferably formed in more than half of the entire area of the blade forming portion 112 in the radial direction from the outer periphery. This makes it easier to visually check the inside of the blade forming portion 112, and makes it easier to remove unhardened sand while checking for remaining sand. Therefore, the remaining unhardened sand in the blade forming portion 112 is suppressed.

The opening 130 formed in the blade forming portion 112 is covered by the lid portion 200 during casting. FIG. 2 is a diagram showing the state in which the lid portion 200 is installed so as to cover the opening 130. The lid portion 200 may be formed so as to cover the opening 130, but it is preferable that it is formed to match the shape of the opening 130 as shown in FIG. 2. In other words, it is preferable that the lid portion 200 is formed so that the hollow structure formed by the wall portion 110 during casting has the same shape as the casting. This can suppress the occurrence of burrs and reduce the effort required to process the casting after casting.

In addition, the lid portion 200 preferably has a positioning structure that fixes the position of the lid portion 200 relative to the main body portion 100. The lid portion 200 has a lid main body portion 205 and a claw portion 210. The lid main body portion 205 is a flat plate-like portion that closes the opening portion 130, and forms the main surface of the blade during casting. The lid portion 200 may be composed of only the lid main body portion 205, but it is preferable that the lid portion 200 has a claw portion 210. The claw portion 210 functions as a positioning structure, and the inner side contacts the outer surface of the blade forming portion 112. Since the lid portion 200 has the claw portion 210, the position of the lid portion 200 relative to the main body portion 100 can be fixed. In addition, by fixing the lid portion 200 in an appropriate position, the occurrence of burrs can be suppressed.

In Figs. 1 and 2, three claw portions 210 are provided for one lid portion 200, but the number and positions of the claw portions 210 provided for one lid portion 200 are not particularly limited. Also, in Figs. 1 and 2, the claw portions 210 are in contact with a portion of the outer surface of the wing forming portion 112, but they may be formed so as to be in contact with the entire outer surface of the wing forming portion 112.

Although the above describes a case where the number of vane forming portions 112 is three, the number of vane forming portions 112 is not limited to three and is determined according to the casting to be manufactured using the mold 1. Furthermore, the vane forming portions 112 do not have to have the same shape, and may have different shapes. Furthermore, the vane forming portions 112 do not have to be arranged at equal intervals, and the intervals between the vane forming portions 112 may differ.

The opening 130 may be provided on one of the main surfaces of the blade forming portion 112, or on the underside. However, it is preferable that the opening 130 be provided on the upper surface of the blade forming portion 112, as this makes it easier to fix the lid portion 200 thereto.

[Method of manufacturing the mold]
(Entire process)
A method for manufacturing the mold 1 configured as above will be described. The mold 1 is manufactured using a layered 3D printer (additive manufacturing device). A commercially available binder jet type 3D printer can be used as the 3D printer.

The data for the mold 1 input to the 3D printer is not designed to have a structure in which the hollow structure is closed by a wall 110 so as to form the shape of the casting, but is designed to have a structure in which a portion is open by forming an injection port 120 and an opening 130. The injection port 120 serves as an injection port for the molten metal, and the opening 130 serves as an outlet for the unhardened modeling sand.

In this way, a 3D printer is used to spread sand to a uniform thickness, and a series of processes is repeated to form the model, in which a binder is sprayed onto the designated area that will become the model and then hardened. This makes it possible to maintain high dimensional accuracy even for molds with complex shapes without dividing them into multiple parts. Details of modeling materials will be provided later.

When the molding is completed, the hardened molded body (e.g., mold 1) is buried in unhardened sand inside the formed laminate. The molded body is extracted by removing the unhardened sand from the laminate. If the molded body is hollow, unhardened sand remains in the hollow even after removing the surrounding unhardened sand. It is possible to discharge some of the unhardened sand from the inlet 120, but it is difficult to remove the unhardened sand from the inlet 120, especially in the blade forming part 112 that is formed to protrude in a direction different from the central axis. In response to this, by providing an opening on one of the main surfaces of the blade forming part 112, it is possible to remove the unhardened sand while checking the remaining sand. This prevents unhardened sand from remaining in the blade forming part, improving the dimensional accuracy of the mold.

(Modeling materials)
For the molding sand, sand dedicated for layered 3D printers is used. Sands available on the market as dedicated sands can be appropriately selected and used. Examples of commercially available dedicated sands include genuine materials for 3D printers and TCaST (registered trademark, manufactured by Pacific Cement Corporation). The dedicated sand can be selected, for example, taking into consideration the heat resistance according to the molten metal temperature to be cast. Furthermore, commercially available dedicated sand may be improved and used as the molding sand. The average particle size of the molding sand is preferably 60 μm or more and 150 μm or less, and more preferably about 100 μm.

The binder may be an organic material such as phenolic resin or furan resin that hardens by condensation or polymerization, but depending on the type of organic material, use at high temperatures may be restricted. Therefore, when using at high temperatures, or when trying to prevent environmental impacts such as odors caused by the evaporation of organic materials during casting, or defects in castings caused by the generated gases, it is preferable for the binder to be primarily composed of inorganic hydraulic substances such as calcium aluminate, cement, gypsum, and lime.

[Casting method]
(Entire process)
A casting method using the above mold 1 will now be described.

During casting, the opening 130 is first sealed with the lid 200. At this time, a fixing member such as an adhesive or adhesive tape may be used to fix the position of the lid 200. The fixing member must be a material that does not contain metal so as not to change the composition of the mold, and is composed of, for example, an organic material. The adhesive tape is, for example, masking tape or packing tape. The fixing member will carbonize during casting, but as will be described later, the outer surface of the mold 1 will be covered with casting sand, so carbonization does not pose a problem.

Next, the mold 1, whose opening 130 is covered by the lid 200, is placed inside the flask. The flask is cylindrical or box-shaped with an open top, and there are no particular limitations on its shape or size, so long as it can cover the outer surface of the mold 1 when filled with casting sand. There are no particular limitations on the material of the flask, either, but it can be a wooden or metal frame commonly used for a flask.

After placing the mold 1 inside the flask, the space between the inner surface of the flask and the outer surface of the mold 1 is filled with molding sand, and the mold 1 is fixed in place. At this time, it is preferable that the molding sand is filled inside the flask so that the outer surface of the mold 1 is covered with the molding sand except for the injection port 120.

During casting, the mold 1 is subjected to pressure from the inside by the molten metal poured into its hollow structure. The purpose of placing the mold 1 inside the flask and filling the flask with casting sand is to prevent the molten metal from leaking from the opening 130, but also to prevent deformation or damage to the mold 1 due to the pressure of the molten metal. If the mold 1 is deformed or damaged, there is a risk that a casting of the specified dimensions will not be obtained.

When mold 1 is ready, molten metal is poured into mold 1, and after the molten metal has cooled, the casting produced in mold 1 is removed. At this time, mold 1 is disassembled. The produced casting has a shaft portion that is arranged along the central axis of the casting, and a wing portion that extends in a direction different from the central axis.

(molding sand)
The molding sand can be selected from commonly used molding sands. For example, silica sand, zircon sand, chromite sand, olivine sand, alumina sand, artificial sand (ceramic type), and a mixture of these can be used as the molding sand. There are no particular limitations on the sand used for the molding sand, and it can be selected from the viewpoint of heat resistance according to the metal to be cast.

The molding sand may also contain a binder. This can improve the strength of the molding sand and prevent deformation or damage due to the pressure of the molten metal. If the molding sand does not contain a binder, the strength can be improved by placing a weight on top of the molding sand filled into the flask, which can prevent deformation or damage due to the pressure of the molten metal.

[Second embodiment]
In the above mold 1, the lid 200 has a claw 210, but as shown in FIG. 3, a spigot may be formed on the side as a positioning structure so that the opening 130 and the lid 200 are engaged. The spigot is a structure in which parts in a concave and convex state engage with each other. When the 12A side in FIG. 3 is the vertical upper side and the 12B side is the vertical lower side, the opening 130 has a step protruding vertically downward, and the lid 200 has a step protruding vertically upward, and when the lid 200 is fitted into the opening 130, the steps engage with each other. Even if the lid 200 is moved in the direction of the thick arrow, it is engaged by the opening 130, preventing the lid 200 from entering the hollow part of the main body 100.

[Third embodiment]
Next, a third embodiment of the present invention will be described. The main body of the third embodiment has a single blade forming portion, and is different from that of the first embodiment in that it has a hollow space that forms the spirally continuous blade portion 912, but has a similar configuration in other respects.

Figure 4 is a perspective view showing the main body 300 and the lid 400. As shown in Figure 4, the main body 300 has a wall 310 including a shaft forming portion 311 and a blade forming portion 312. One blade forming portion 312 is provided for each main body 300, and has a hollow that forms a blade portion 912 that continues in a spiral shape.

In the blade forming section 312, for example, an opening 330 is provided in the area surrounded by the dotted line. In order to prevent unhardened sand from remaining in the blade forming section 312, it is preferable to provide multiple openings 330 so that the remaining sand in all areas of the blade forming section 312 can be confirmed. This makes it possible to remove the unhardened sand while checking the remaining sand, thereby preventing unhardened sand from remaining in the blade forming section. In addition, in the casting mold 3, as in the casting mold 1, each opening 330 is covered with a lid 400 during casting.

The mold 3 produces the casting 900 shown in FIG. 6 by casting. The casting 900 shown in FIG. 6 has a shaft portion 911 arranged along the central axis and a vane portion 912 protruding in a direction different from the central axis. The vane forming portion 312 having a hollow that forms the spirally continuous vane portion 912 may be formed so that the pitch P of the vane portion 912 and the distance from the central axis to the outer edge change depending on the position on the central axis.

[Fourth embodiment]
The body 300 of the mold 3 described above has a hollow shaft forming portion 311 used for casting the shaft portion, but it is not necessary to have the hollow shaft forming portion 311 used for casting the shaft portion. For example, in the body 700 shown in Fig. 5, the wall portion 710 forms only hollow blade forming portions 712. The blade forming portions 712 are used for casting a casting having only spirally continuous blade portions without a shaft portion.

Even in the case of a mold 3 that does not have an axis forming portion 311, it is preferable that the axis forming portion is formed in a portion excluding a specified area on the central axis side. By providing a specified area, it is easier to process burrs that occur between the opening and the lid during casting.

[Overview of each embodiment]
As described above, the casting mold according to the present invention makes it possible to remove unhardened sand from the hollow blade-forming portion used for casting the blade portion while checking the remaining sand, thereby preventing unhardened sand from remaining in the blade-forming portion.

[Example]
According to the above method, a mold was prepared and casting was performed. A CJP660 (manufactured by 3D SYSTEMS) was used as the 3D printer. TCaST (manufactured by Taiheiyo Cement Corporation, average particle size 100 μm) was used as the molding sand.

As an example, a mold having the shape shown in Figures 1 and 2 was produced. The molding conditions are as shown in Table 1. The produced mold had a wall thickness (thickness of the wall and lid) of 5 mm. The opening was formed so that sand residue could be confirmed in all areas of the blade forming portion. In addition, as a comparative example, a mold similar to the example was produced, except that it was an integrated mold without forming an opening and a lid corresponding to the opening.

First, the unhardened sand remaining in the mold was removed, and the time required for removal, visibility, and remaining sand were evaluated. The evaluation results are shown in Table 2. The time required for sand removal was evaluated based on the comparative example, with ◯ being the standard if it took about the same time as the comparative example, and ◎ being the standard if it took less time than the comparative example. For visibility, if the unhardened sand in the blade formation portion could be seen, it was evaluated as ◎, and if it could not be seen, it was evaluated as △. For remaining sand, the weight of the mold after the removal of the unhardened sand was measured, and if the weight of the mold was about the same as the weight expected from the design, it was evaluated as ◎, and if it was heavier than the expected weight, it was evaluated as △, as there was remaining sand.

Next, casting and mold disassembly were performed, and if this was done without any problems, it was rated as ○. Then, the castings produced from the molds of the example and comparative example were evaluated for accuracy, casting surface, and burrs. The evaluation results are shown in Table 3. With regard to the accuracy of the casting, if it was as designed, it was rated as ◎, and if there were minor defects, it was rated as ○. With regard to the casting surface, if there was no roughness, it was rated as ○. With regard to burrs, if no burrs were generated, it was rated as ◎, and if burrs were generated but could be easily processed, it was rated as ○.

In the comparative mold, since there was no opening, it was not possible to check for remaining sand in the blade formation area, and unhardened sand remained. Furthermore, the remaining unhardened sand caused minor imperfections in the precision of the casting produced from the mold. On the other hand, since it was a one-piece mold, no burrs were produced.

In contrast, the mold of the embodiment has an opening in the blade forming area, so that unhardened sand can be removed while checking the remaining sand in the blade forming area. This improves the accuracy of the casting compared to the comparative example. Also, although burrs were generated between the opening and the lid, this was easily achieved because the opening was provided to avoid the base of the blade forming area.

In a component having a wing portion that protrudes in a direction different from the central axis, the dimensional accuracy of the mold can be improved, thereby improving the performance of the casting itself produced by the mold. Therefore, the examples, which produce castings with higher accuracy, are preferable to the comparative examples.

Reference Signs List 1, 3 Mold 100, 300, 700 Body 110, 310, 710 Wall 111, 311 Shaft forming portion 112, 312, 712 Blade forming portion 120, 320, 720 Inlet 130, 330, 730 Opening 200, 400 Lid 205 Lid body 210 Claw 900 Casting 911 Shaft 912 Blade P Pitch

Claims (9)

A mold that is manufactured using shaping sand by an additive manufacturing device and is capable of casting a member having a wing portion protruding in a direction different from a central axis,
a main body having a hollow blade-forming portion used for casting the blade portion, the main body having an opening formed in at least one main surface of the blade-forming portion;
and a lid portion that covers the opening. The main body further includes a shaft forming portion used for casting a shaft portion provided along the central axis,
The mold according to claim 1 , wherein the opening is formed in a portion excluding a predetermined area on a root side of the wing forming portion. The mold according to claim 1, characterized in that the opening is formed in a portion excluding a predetermined area on the central axis side. The mold according to any one of claims 1 to 3, characterized in that the mold has a positioning structure that fixes the position of the lid portion relative to the body portion. The mold according to claim 4, characterized in that the positioning structure is a claw portion whose inner side contacts the outer surface of the wing forming portion. The main body portion has a plurality of the blade forming portions,
The mold according to any one of claims 1 to 5, characterized in that the openings are formed in each of the wing forming portions. the blade forming portion has a hollow that forms the blade portion that is continuous in a spiral shape,
The mold according to any one of claims 1 to 5, characterized in that a plurality of the openings are formed. A method for producing a mold according to any one of claims 1 to 7, comprising the steps of:
A step of spreading the shaping sand to a constant thickness;
A method for manufacturing a mold, comprising repeating a series of steps including a step of injecting a binder into a specific portion of the mold that will become the mold as a shaped body and then hardening the binder, thereby forming the shaped body using an additive manufacturing device. A casting method using the mold according to any one of claims 1 to 7,
sealing the opening with the lid;
placing the mold with the opening covered by the lid inside a molding flask;
filling the interior of the flask with molding sand so as to fix the mold;
Pouring molten metal into the mold;
and removing the casting produced in the mold.