Mold, manufacturing method thereof and casting method

Abstract

To provide a mold capable of suppressing the remaining of uncured sands in a hollow blade formation part used for casting a blade part.SOLUTION: A mold 1 is produced by an additional production device using molding sands and can cast a member having a blade part projecting in a direction different from a central axis, and comprises: a body part 100 which has hollow blade formation parts 112 used for casting the blade part, in which one of main faces of the blade formation part being formed with an openings 130; and cover parts 200 covering the openings.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a mold that is produced using shaping sand by an additive manufacturing device and that 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. [Background technology]

[0002] In recent years, molds made with additive 3D printers have become popular. Generally, molds are made by transferring a wooden or metal mold as a prototype, but such molds always require a process called demolding, and the wooden or metal mold must be shaped so that they can be removed.

[0003] In contrast, a mold made with a layered 3D printer is made by laying a certain thickness of sand, hardening only the necessary parts, and layering them in order, so there is no need to remove the mold. Therefore, even molds with shapes that have a reverse slope, for example, can be easily made.

[0004] 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 they are produced, the lower the dimensional accuracy becomes, which can lead to a decrease in performance. However, with additive 3D printers, there are no restrictions on shapes, and there is no need to produce sections even for complex shapes, so additive 3D printers are increasingly being used to produce components with blades.

[0005] For example, the part shown in Fig. 6 can be produced using the mold shown in Fig. 7A and B, which is produced by an additive 3D printer. The mold shown in Fig. 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 Fig. 8A and B.

[0006] In addition, the manufacture of members having blades is often performed by lost wax casting, but lost wax casting requires the manufacture of a wax pattern for the casting, which is very time-consuming (see Patent Documents 1 and 2). In addition, lost wax casting is not suitable for the manufacture of large castings, and the types of castings that can be produced are limited. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 07-16701 [Patent Document 2] JP 2003-94148 A [Patent Document 3] JP 2003-275846 A Summary of the Invention [Problem to be solved by the invention]

[0008] As mentioned above, molds made with additive 3D printers are not limited in shape and can be made in complex shapes, making them suitable for molds of components with wings. However, when making molds with additive 3D printers, it is necessary to remove the unhardened sand remaining in the hollow structure after the molding is completed. If unhardened sand remains, there is a risk that the desired shape will not be obtained when casting.

[0009] It is desirable to remove unhardened sand while visually checking that no sand remains, but in a mold for a component having a blade as shown in Figure 6, it is difficult to visually check whether or not there is any sand remaining in the hollow blade-forming portion used for casting the blade, and therefore unhardened sand is likely to remain in the blade-forming portion.

[0010] 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 for saving 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.

[0011] The present invention has been made in consideration of the above circumstances, and has an object to provide a mold that can prevent unhardened sand from remaining in the hollow blade forming portion used in casting the blade portion, as well as a manufacturing method and a casting method for the same. [Means for solving the problem]

[0012] (1) In order to achieve the above object, the mold of the present invention is a mold produced by an additive manufacturing device using shaping sand and capable of casting a component having a blade portion protruding 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 in at least one main surface of the blade forming portion, and a lid portion covering the opening.

[0013] In this way, since the device is provided with a main body portion having an opening formed on at least one of the main surfaces of the blade forming portion, and a lid portion covering the opening, it is possible to remove unhardened sand while checking the remaining sand, thereby preventing unhardened sand from remaining in the blade forming portion.

[0014] (2) In the mold of the present invention, the main body further has a shaft forming part that is provided along the central axis and is used for casting a shaft part, and the opening is formed in a part excluding a predetermined area on the root side of the blade forming part, thereby suppressing the occurrence of design errors around the root of the blade forming part.

[0015] (3) In the mold of the present invention, the opening is formed in a portion excluding a predetermined area on the central axis side, thereby suppressing the occurrence of design errors on the central axis side.

[0016] (4) In addition, the mold of the present invention is characterized in that it has a positioning structure for fixing the position of the lid with respect to the body, which makes it possible to position the lid in an appropriate position and suppresses the occurrence of burrs.

[0017] (5) 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 side of the vane forming portion, which makes it easy to position the lid portion in an appropriate position and suppresses the occurrence of burrs.

[0018] (6) In the mold of the present invention, the main body has a plurality of the blade forming parts, and the opening is formed in each of the blade forming parts. This makes it possible to remove unhardened sand from each of the blade forming parts while checking the remaining sand, thereby preventing unhardened sand from remaining in the blade forming parts.

[0019] (7) In the mold of the present invention, the blade-forming portion has a hollow that forms the blade portion in a spiral shape, and a plurality of the openings are formed. This makes it possible to remove unhardened sand while checking the remaining sand even in the blade-forming portion having a hollow that forms a spiral shape, thereby preventing unhardened sand from remaining in the blade-forming portion.

[0020] (8) Furthermore, the method for manufacturing a casting mold of the present invention is a method for manufacturing a casting mold described in any one of (1) to (7) above, characterized in that the shaped body is formed using an additive manufacturing device by repeating a series of steps including a step of spreading the shaping sand evenly to a constant thickness and a step of injecting a binder into a specified portion that will become the casting mold as a shaped body and hardening the binder.

[0021] This makes it easier to remove unhardened molding sand from the openings of the molded body. In addition, high dimensional accuracy can be maintained even for molds with complex shapes without dividing them into multiple parts. Furthermore, improved dimensional accuracy of the mold can improve the performance of the castings produced using the mold.

[0022] (9) A 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, comprising 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 to fix the mold, pouring molten metal into the mold, and removing a casting produced in the mold.

[0023] This makes it difficult for unhardened sand to remain in the blade forming portion, 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. Effect of the Invention

[0024] According to the present invention, in a hollow blade forming section used in 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. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is an exploded perspective view showing a schematic configuration of a mold according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view showing a state in which a lid is placed so as to cover an opening in the mold according to the first embodiment. [Diagram 3] 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. [Figure 4] FIG. 11 is a perspective view showing a schematic configuration of a main body and a lid according to a second embodiment. [Diagram 5] FIG. 11 is a perspective view showing a modified example of the main body according to the second embodiment. [Figure 6] FIG. 2 is a perspective view showing a schematic configuration of a casting. [Figure 7A] FIG. 1 is a perspective view showing a schematic configuration of a conventional mold. [Figure 7B] FIG. 7B is a cross-sectional view taken through the central axis of the mold shown in FIG. 7A. [Figure 8A] FIG. 1 is a perspective view showing a schematic configuration of a conventional mold. [Figure 8B] FIG. 8B is a cross-sectional view taken through the central axis of the mold shown in FIG. 8A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] [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.

[0027] FIG. 1 is a perspective view showing a mold 1 according to a first embodiment of the present invention. The mold 1 is formed of shaping sand and a binder, and has a hollow structure. The shaping sand is sand used to shape a mold using a 3D printer (additive manufacturing device). The binder binds 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.

[0028] The mold 1 of the present invention can cast a member having wings that protrude in a direction different from the central axis. The mold 1 shown in Fig. 1 is composed of a main body 100 and a lid 200. The main body 100 has a hollow structure realized by a wall 110 formed of molding sand and a binder. The hollow structure refers to a structure made of a wall and a hollow portion, and the hollow portion refers to the space itself surrounded by the wall (excluding the wall portion).

[0029] The wall 110 is provided with an inlet 120 for 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 may be formed in a position that allows easy injection of the molten metal, and is preferably formed in a position that will be the upper end during casting.

[0030] 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. Furthermore, it is 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.

[0031] Furthermore, the wall portion 110 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 portions. 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 to each other by their respective hollow structures to form a single hollow structure.

[0032] The blade forming portion 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 portion 112. The opening 130 is preferably formed in a portion excluding a predetermined area on the base side of the blade forming portion 112. If the opening 130 is formed up to the base of the blade forming portion 112, there is a high possibility that an error in meshing when the lid portion 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 portion is integrated to prevent any deviation in accuracy.

[0033] In this way, the predetermined area is the base area that should be formed without error. Providing the predetermined area makes it easier to process burrs that occur between the opening and the lid during casting. In particular, providing the predetermined area at 1 / 4 or more 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.

[0034] Moreover, it is preferable that the opening 130 is formed so that the remaining sand can be confirmed in all areas of the blade forming portion. Therefore, it is preferable that the opening 130 is 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 easy to remove the unhardened sand while checking the remaining sand. Therefore, the remaining unhardened sand in the blade forming portion 112 is suppressed.

[0035] 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 a 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.

[0036] 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 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 the claw portion 210. The claw portion 210 functions as a positioning structure, and the inside 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 at an appropriate position, the occurrence of burrs can be suppressed.

[0037] 1 and 2, three claw portions 210 are provided for one lid portion 200, but there is no particular limitation on the number and positions of claw portions 210 provided for one lid portion 200. In addition, while claw portion 210 contacts a portion of the outer surface of blade forming portion 112 in Figs. 1 and 2, it may be formed so as to contact the entire outer surface of blade forming portion 112.

[0038] 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 provided at equal intervals, and the intervals between the vane forming portions 112 may differ.

[0039] Moreover, opening 130 only needs to be provided on one of the main surfaces of blade forming portion 112, and may be provided on the bottom surface. However, it is preferable that opening 130 be provided on the top surface of blade forming portion 112, as this makes it easier to fix lid portion 200 thereto.

[0040] [Mold manufacturing method] (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.

[0041] The data for the mold 1 input to the 3D printer is designed so that the hollow structure is not closed by the wall 110 so as to form the shape of the casting, but is partially open by forming the injection port 120 and the opening 130. The injection port 120 serves as the injection port for the molten metal, and the opening 130 serves as the discharge port for the unhardened modeling sand.

[0042] In this way, the 3D printer spreads sand to a certain thickness, injects binder into the designated area of ​​the object, and hardens it, repeating the process to form the object. This makes it possible to maintain high dimensional accuracy even for molds with complex shapes without dividing them into multiple parts. Details of the molding materials will be described later.

[0043] When molding is completed, the hardened molded body (e.g., mold 1) is buried in unhardened sand in the formed laminate. The molded body is taken out by removing the unhardened sand from the laminate. If the molded body is hollow, unhardened sand remains in the hollow even if the surrounding unhardened sand is removed. Although it is possible to discharge some of the unhardened sand from the inlet 120, it is difficult to remove the unhardened sand from the inlet 120, particularly in the blade forming portion 112 formed to protrude in a direction different from the central axis. In response to this, by providing an opening on one main surface of the blade forming portion 112, it is possible to remove the unhardened sand while checking the remaining sand. Therefore, it is possible to prevent unhardened sand from remaining in the blade forming portion, and improve the dimensional accuracy of the mold.

[0044] (Modeling materials) The molding sand is special sand for layered 3D printers. Any commercially available special sand can be appropriately selected and used. Examples of commercially available special sand include genuine materials for 3D printers and TCaST (registered trademark, manufactured by Taiheiyo Cement Corporation). The special sand can be selected, for example, taking into consideration the heat resistance according to the molten metal temperature to be cast. Furthermore, commercially available special sand may be modified 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.

[0045] The binder may be an organic material such as a phenolic resin or a 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 vaporization of organic materials during casting, or defects in castings caused by the generated gas, it is preferable for the binder to be mainly composed of an inorganic hydraulic material such as calcium aluminate, cement, gypsum, or lime.

[0046] [Casting method] (Entire process) A casting method using the above mold 1 will now be described.

[0047] During casting, first, the opening 130 is sealed with the lid 200. At this time, a fixing member such as an adhesive or an 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 be carbonized 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.

[0048] Next, the mold 1 with the opening 130 covered by the lid 200 is placed inside the flask. The flask is cylindrical or box-shaped with an open top, and there is no particular limitation on its shape or size as long as it can cover the outer surface of the mold 1 when filled with molding sand. There is no particular limitation on the material of the flask, either, and it may be a wooden or metal frame commonly used as a molding flask.

[0049] After the mold 1 is placed inside the flask, molding sand is filled between the inner surface of the flask and the outer surface of the mold 1, and the mold 1 is fixed. At this time, it is preferable that the molding sand is filled inside the flask so that the part of the outer surface of the mold 1 other than the injection port 120 is covered with the molding sand.

[0050] During casting, the mold 1 is subjected to pressure from within by the molten metal poured into its hollow structure. The purpose of placing the mold 1 inside the flask and filling the flask with molding sand is to prevent the molten metal from leaking from the opening 130, but also to prevent the mold 1 from being deformed or damaged by 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.

[0051] When the mold 1 is prepared, molten metal is poured into the mold 1, and after the molten metal has cooled, the casting produced in the mold 1 is removed. At this time, the mold 1 is disassembled. The produced casting has a shaft portion that is provided along the central axis of the casting, and wing portions that extend in a direction different from the central axis.

[0052] (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.

[0053] The molding sand may also contain a binder, which 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 the molding sand filled in the flask, which can prevent deformation or damage due to the pressure of the molten metal.

[0054] [Second embodiment] In the above mold 1, the lid 200 has the claws 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 of FIG. 3 is the vertical upper side and the 12B side is the vertical lower side, the opening 130 has a step that protrudes vertically downward, and the lid 200 has a step that protrudes 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.

[0055] [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 otherwise has a similar configuration.

[0056] Fig. 4 is a perspective view showing main body 300 and cover 400. As shown in Fig. 4, main body 300 has wall 310 including shaft forming portion 311 and blade forming portion 312. Blade forming portion 312 is provided for each main body 300, and has a hollow portion that forms blade portion 912 that continues in a spiral shape.

[0057] 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 a plurality of 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 the mold 3, as in the mold 1, each opening 330 is covered with a lid 400 during casting.

[0058] Mold 3 produces casting 900 shown in Fig. 6 by casting. Casting 900 shown in Fig. 6 has shaft portion 911 provided along the central axis, and blade portions 912 protruding in a direction different from the central axis. Blade forming portion 312 having a hollow that forms spirally continuous blade portions 912 may be formed so that the pitch P of blade portions 912 and the distance from the central axis to the outer edge vary depending on the position on the central axis.

[0059] [Fourth embodiment] The main 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 main 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.

[0060] 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 predetermined area on the central axis side. By providing the predetermined area, it becomes easier to process burrs that occur between the opening and the lid during casting.

[0061] [Summary 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.

[0062] [Example] Following the above method, a mold was made and casting was performed. The 3D printer used was CJP660 (manufactured by 3D SYSTEMS). The molding sand used was TCaST (manufactured by Taiheiyo Cement Corporation, average particle size 100 μm).

[0063] 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 part. In addition, as a comparative example, a mold was produced that was similar to the example, except that it was an integrated mold without forming an opening and a lid corresponding to the opening. [Table 1]

[0064] 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 the same amount of 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 area 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 unhardened sand had been removed 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. [Table 2]

[0065] 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. For the accuracy of the casting, if it was as designed, it was rated as ◎, and if there were minor defects, it was rated as ○. For the casting surface, if there was no roughness, it was rated as ○. For burrs, if no burrs were generated, it was rated as ◎, and if burrs were generated but could be easily processed, it was rated as ○. [Table 3]

[0066] In the comparative mold, since there was no opening, it was not possible to check the remaining sand in the blade forming portion, and unhardened sand remained. In addition, the remaining unhardened sand caused minor defects in the accuracy of the casting produced from the mold. On the other hand, since it was a one-piece mold, no burrs were generated.

[0067] In contrast, in the mold of the embodiment, an opening is provided in the blade forming portion, so that the unhardened sand can be removed while checking the remaining sand in the blade forming portion. This improves the accuracy of the casting compared to the comparative example. Also, although burrs were generated between the opening and the lid, they could be easily processed because the opening is provided avoiding the base of the blade forming portion.

[0068] In a member having vanes protruding in a direction different from the central axis, the dimensional accuracy of the mold can be improved, and the performance of the casting produced by the mold can be improved. Therefore, the examples, which produce castings with higher accuracy, are preferable to the comparative examples. [Explanation of symbols]

[0069] 1, 3 Mold 100, 300, 700 Main unit 110, 310, 710 Wall section 111, 311 Shaft forming part 112, 312, 712 Blade forming part 120, 320, 720 inlet 130, 330, 730 opening 200, 400 Lid 205 Lid body part 210 Claw part 900 Casting 911 Shaft 912 Wing Pitch

Claims

1. 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.

2. 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.

3. The mold according to claim 1 , wherein the opening is formed in a portion excluding a predetermined region on the central axis side.

4. 4. The mold according to claim 1, further comprising a positioning structure for fixing the position of the lid portion relative to the body portion.

5. 5. The mold according to claim 4, wherein the positioning structure is a claw portion whose inner side contacts the outer surface of the wing forming portion.

6. 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.

7. 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.

8. 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.

9. 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.

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