JP6872398B2 - Resin-integrated core manufacturing method, mold manufacturing method, and resin-integrated core - Google Patents

Description

The present invention relates to a method for producing a resin-integrated core, a method for producing a mold, and a resin-integrated core.

For example, the blades of a gas turbine are exposed to hot working gas. Therefore, in order to keep the temperature of the rotor blade lower, a cooling medium is flowed inside the rotor blade to cool the rotor blade.
The gas turbine blade is provided with an internal cooling structure in order to allow the cooling medium to flow inside. Precision casting is generally used to manufacture such gas turbine blades. When manufacturing a gas turbine blade having an internal cooling structure using precision casting, a core having the same shape as the flow path of the cooling medium is arranged, and the core is removed after casting (). For example, see Patent Document 1.).

As a method for producing such a core, an injection molding method using a mold and a slip casting method in which the core is directly molded from a slurry are known. On the other hand, in order to improve performance, the internal cooling structure has become complicated and fine, and as an alternative method to these manufacturing methods, for example, a molding device such as a 3D (three-dimensional) printer is used to manufacture a complicated and fine core. A resin 3D additive manufacturing method has been attempted.

JP-A-2002-28751

However, in the resin 3D additive manufacturing method, the strength may be insufficient, for example, cracks are generated in the core during injection molding of wax (wax).

The present invention provides a resin-integrated core manufacturing method, a mold manufacturing method, and a resin-integrated core capable of preventing a core having a complicated and fine structure from being deformed or damaged. With the goal.

According to the first aspect of the present invention, the method for producing a resin-integrated core includes a resin structure forming step of forming a resin structure made of a resin and supplying a slurry to the resin structure to obtain the slurry. The resin structure is hollow, comprising a curing step of forming a resin-integrated core in which the core is covered with the resin structure by curing.

According to such a configuration, since the core is covered with the resin structure, it is possible to prevent the core from being deformed or damaged during injection molding of wax in the casting manufacturing process. Can be done.
Further, even when the resin structure expands during the mold firing step, the pressure applied to the core can be absorbed because the resin structure has a hollow structure. This makes it possible to prevent the core from being deformed or damaged during the mold firing step.

In the method for manufacturing a resin-integrated core, the resin structure forming step is an inner / outer surface that forms an outer surface portion that forms an outer surface of the resin structure and an inner surface portion that is a molding surface that forms the core. A molding step may be included.

In the method for producing a resin-integrated core, the resin structure forming step may include a space portion forming step of defining a plurality of spaces between the outer surface portion and the inner surface portion.
Further, the method for producing the resin-integrated core includes a resin structure forming step of forming a resin structure made of resin, and supplying a slurry to the resin structure to cure the slurry to cure the resin structure. A curing step of forming a resin-integrated core in which the core is covered with the core is provided, and the resin structure forming step forms an outer surface portion forming the outer surface of the resin structure and the core. The resin structure forming step includes an inner / outer surface forming step of forming an inner surface portion which is a molding surface, and the resin structure forming step includes a space portion forming step of defining a plurality of spaces between the outer surface portion and the inner surface portion. May include.
Further, the method for producing the resin-integrated core includes a resin structure forming step of forming a resin structure made of resin, and supplying a slurry to the resin structure to cure the slurry to cure the resin structure. A curing step of forming a resin-integrated core in which the core is covered with the core is provided, and the resin structure forming step forms an outer surface portion forming the outer surface of the resin structure and the core. Includes an inner / outer surface forming step of forming an inner surface portion which is a molding surface, and a space portion forming step of defining a plurality of spaces by forming a wall portion between the outer surface portion and the inner surface portion. Good.

In the method for producing a resin-integrated core, at least a part of the plurality of spaces may be formed in a grid pattern.
According to such a configuration, the resin structure can be deformed in a well-balanced manner.

In the method for producing a resin-integrated core, the resin structure may be formed by a 3D additive manufacturing method.
With such a configuration, it is possible to easily form a three-dimensional shape that is difficult to form with existing technology.

According to the second aspect of the present invention, the mold manufacturing method is a wax mold in which wax is supplied between the mold and the resin-integrated core, and the resin-integrated core is included by the wax. A wax mold forming step of forming a mold, a mold molding step of supplying a mold material to the outer surface of the wax mold to mold a mold structure, and a dewaxing step of heating the mold structure to remove the wax. After removing the wax, the mold structure is heated and fired, and the mold firing step of removing the resin is provided.

According to such a configuration, since the core is covered with the resin structure, when the wax is supplied between the mold and the resin-integrated core in the wax mold forming step, the core is formed. It is possible to prevent the child from being deformed or damaged. Further, when the wax heated in the dewaxing step expands, it is possible to prevent the core from being deformed or damaged.

According to the third aspect of the present invention, the resin-integrated core includes a core and a resin structure made of resin and covering the core from the outside, and the resin structure has an outer surface forming an outer surface. It has a portion, an inner surface portion forming an inner surface which is a molding surface forming the core, and a plurality of spaces defined between the outer surface portion and the inner surface portion.
Further, the resin-integrated core includes a core and a resin structure made of resin and covering the core from the outside, and the resin structure has an outer surface portion forming an outer surface and a molding forming the core. It has an inner surface portion forming an inner surface which is a surface, and a plurality of spaces defined by a wall portion formed between the outer surface portion and the inner surface portion.

In the resin-integrated core, the resin structure is formed of a resin having a melting point of 190 ° C. or higher, and may be used for precision casting.

In the resin-integrated core, the resin structure is defined between an outer surface portion forming an outer surface, an inner surface portion forming an inner surface which is a molding surface forming the core, and the outer surface portion and the inner surface portion. It may have a plurality of spaces that are created.

In the resin-integrated core, the core may have a partially exposed exposed portion, which is a connecting surface formed of a connecting line connecting the outer surface portion and the inner surface portion.

In the resin-integrated core, at least a part of the plurality of spaces may be arranged in a grid pattern.

In the resin-integrated core, the resin structure may be composed of a 3D laminated molding material.

According to the present invention, it is possible to prevent the core from being deformed or damaged because the core is covered with the resin structure.

It is a flowchart of the manufacturing method of the resin-integrated core of the embodiment of this invention. It is sectional drawing of the resin structure of embodiment of this invention. It is sectional drawing of the resin-integrated core of the embodiment of this invention. It is a flowchart of the manufacturing method of the mold of the embodiment of this invention. It is sectional drawing explaining the wax mold forming process of the mold manufacturing method of embodiment of this invention. It is the schematic explaining the wax mold of embodiment of this invention. It is the schematic explaining the mold structure of embodiment of this invention.

Hereinafter, the resin-integrated core manufacturing method, the mold manufacturing method, and the resin-integrated core according to the embodiment of the present invention will be described in detail with reference to the drawings.
The mold manufacturing method of the present embodiment is a method for manufacturing a mold used for precision casting, for example, a method for manufacturing a mold for a gas turbine moving blade (casting) having a cooling medium flow passage which is an internal cooling structure. is there. As the mold manufacturing method, the resin-integrated core 1 (see FIG. 3) manufactured by the resin-integrated core manufacturing method is used. The resin-integrated core 1 has a core 3 (core) having the same shape as the cooling medium flow path, and a resin structure 2 that covers the core 3 from the outside.

First, a method for manufacturing a resin-integrated core that manufactures a resin-integrated core 1 in which the resin structure 2 and the core 3 are integrated will be described. The core 3 has a shape corresponding to a cavity inside a casting manufactured by a mold. The core 3 is arranged in a portion corresponding to the cavity inside the casting to prevent the metal to be the casting from flowing in during casting. Further, the resin structure 2 disappears in the mold firing step in the mold manufacturing method.

As shown in FIG. 1, the method for producing a resin-integrated core includes a slurry generation step S11 for producing a slurry forming the core 3, a resin structure forming step S12 for forming a resin structure 2, and a slurry for resin. A curing step S13 of supplying the structure 2 to the cavity V (see FIG. 2) to cure the slurry, and a drying step S14 of drying the core 3 formed of the ceramic formed by curing the slurry are provided. There is.

The slurry generation step S11 is a step of producing a slurry which becomes a core 3 formed of ceramic by solidifying. The slurry can be produced, for example, by dissolving a dispersant, a cross-linking agent, and water in a silica material (powder).

The resin structure forming step S12 is a step of forming the resin structure 2 made of resin by using the resin 3D additive manufacturing method.
Further, in the resin structure forming step S12, as shown in FIG. 2, the inner / outer surface molding for forming the outer surface portion 2a forming the outer surface of the resin structure 2 and the inner surface portion 2b forming the inner surface of the resin structure 2 is formed. Includes step S12A. Further, the resin structure forming step S12 includes a space forming step S12B for defining at least one space S between the outer surface portion 2a and the inner surface portion 2b.
The resin structure 2 is a structure having a function as a mold of the core 3 and a function of protecting the core 3. The resin structure 2 of the present embodiment is made of a 3D laminated molding material.
The resin 3D additive manufacturing method is a method of modeling an object having a three-dimensional shape by using a molding device such as a 3D (three-dimensional) printer, for example. A 3D printer can easily form a three-dimensional shape that is difficult to form with existing technology without the need for costly molds 8 and jigs.

Further, as a resin 3D additive manufacturing method, a slurry additive manufacturing technique using a slurry in which ceramic fine particles are dispersed in a photocurable or thermosetting liquid resin can also be adopted. The slurry lamination molding technique is a technique in which photo-curing or thermosetting is generated in a limited region by laser irradiation to form a two-dimensional cross section having an arbitrary shape, and by repeating this, a three-dimensional molded body is obtained.

As shown in FIG. 2, the resin structure 2 is formed of resin and has an outer surface portion 2a forming an outer surface and an inner surface portion 2b forming an inner surface forming a core 3 (see FIG. 3). It has wall portions 5 and 6 that define a plurality of spaces S between the outer surface portion 2a and the inner surface portion 2b. In the inner / outer surface molding step S12A, the outer surface portion 2a and the inner surface portion 2b are molded by using the resin 3D additive manufacturing method. In the inner / outer surface forming step S12A, the slurry supply port is formed by the connecting line C connecting the outer surface portion 2a and the inner surface portion 2b.
The resin is, for example, a resin such as a urethane resin or an epoxy resin, and has a melting point of 190 ° C. or higher. These resins are not limited to the above examples, and any resin may be used as long as it has strength up to about 190 ° C. and has elasticity.

The molded surface formed by the inner surface portion 2b has a shape that follows the core 3. In other words, the resin structure 2 is formed so that the shape of the slurry becomes the shape of the core 3 by pouring the slurry into the cavity V of the resin structure 2.
The outer surface portion 2a of the resin structure 2 is formed so as not to interfere with the molding surface of the mold 8 for manufacturing castings.
The wall thickness of the inner surface portion 2b is preferably formed to be thicker than the wall thickness of the outer surface portion 2a. By increasing the wall thickness of the inner surface portion 2b, deformation of the inner surface portion 2b is suppressed, and the core 3 can have a fine structure. On the other hand, the amount of resin used can be reduced by making the wall thickness of the outer surface portion 2a thinner than that of the inner surface portion 2b.

The resin structure 2 has a hollow structure. That is, at least one space S is formed between the inner surface portion 2b and the outer surface portion 2a of the resin structure 2. In the space forming step S12B, at least a space S is defined between the outer surface portion 2a and the inner surface portion 2b by using the resin 3D additive manufacturing method.
As the hollow structure, a structure in which a plurality of spaces S are regularly arranged three-dimensionally is preferable. For example, the resin structure 2 has a plurality of first wall portions 5, a plurality of second wall portions 6, and a plurality of third wall portions (not shown), and is formed by these wall portions 5, 6. It may have a plurality of spaces S to be created.

The first wall portions 5 are arranged in the first direction at predetermined intervals. The second wall portion 6 is arranged at a predetermined interval in the second direction orthogonal to the first direction. The third wall portions are arranged at predetermined intervals in the first direction and the third direction orthogonal to the second direction. By arranging the space S in this way, the resin structure 2 can be made into a grid-like (mesh-like) hollow structure. That is, at least a part of the space S can be arranged in a grid pattern.
The structure of the space S formed inside the resin structure 2 is not limited to this, and one space S may be provided without providing a wall portion. Further, the space S may be defined only by the first wall portion 5. Further, a plurality of spaces S may be formed by the honeycomb structure.

The curing step S13 is a step of supplying the slurry generated in the slurry generation step S11 to the cavity V of the resin structure 2 and then curing the slurry. The slurry may be supplied while applying injection pressure. When the slurry is supplied to the cavity V of the resin structure 2 and a predetermined time elapses, the curing of the slurry is completed and the slurry becomes a molded product (core 3). As a result, the resin-integrated core 1 in which the core 3 is covered with the resin structure 2 is formed.

In the drying step S14, the moisture in the silica is evaporated to dry the molded product (core 3) of the slurry. As a drying method, for example, a method of introducing a molded product into a predetermined moisture drying furnace can be adopted.
The drying method is not limited to the above method, and for example, a hot air drying method in which hot air generated by a gas burner is introduced for drying, a natural drying method in which the product is left at room temperature, or the like may be adopted.

By carrying out the above steps, the resin-integrated core 1 as shown in FIG. 3 can be obtained. The resin-integrated core 1 is a structure in which the ceramic core 3 is protected by a resin structure 2 formed of a resin.
As shown in FIG. 3, the core 3 of the resin-integrated core 1 is a connecting surface F composed of a connecting line C connecting the outer surface portion 2a and the inner surface portion 2b, and the exposed portion 3a is partially exposed. Have.

Next, a mold manufacturing method using the resin-integrated core 1 will be described.
As shown in FIG. 4, in the mold manufacturing method of the present embodiment, the mold manufacturing step S21 for manufacturing the mold 8 and the wax mold forming in which the wax W (wax) is supplied to the mold 8 in which the core 3 is set are formed. Step S22, wax mold assembly step S23 for assembling the wax mold 9, mold molding step S24 for molding the mold structure 11 on the outer surface of the wax mold 9, dewaxing step S25 for melting the wax W, and firing the mold. It includes a mold firing step S26.

The mold manufacturing step S21 is a step of manufacturing a casting mold 8 (see FIG. 5). The mold 8 has an inner surface corresponding to the outer surface of the casting. The mold 8 may be formed of metal or ceramic.
As shown in FIG. 5, the wax mold forming step S22 is a step of injecting the wax W into the mold 8 in which the resin-integrated core 1 is set to form the wax mold 9.

In the wax mold forming step S22, the resin-integrated core 1 is arranged at a predetermined position of the mold 8. Next, wax W (about 70 ° C.) is supplied to the cavity V2 of the mold 8 (between the mold 8 and the resin-integrated core 1), and the entire area of the cavity V2 is filled with the wax W. After that, as shown in FIG. 6, the wax W is solidified to form a wax mold 9 in which the resin-integrated core 1 is included by the wax W. In the wax mold 9, the portion formed by the wax W has the same shape as the casting.

In the wax mold forming step S22, pressure is applied to the resin-integrated core 1 by filling the wax W to which the injection pressure is applied between the mold 8 and the resin-integrated core 1.

The wax mold assembly step S23 is a step of attaching a sprue 10 (see FIG. 7) or the like to the wax mold 9 and assembling the wax mold 9.
In the wax mold assembly step S23, the wax mold 9 is separated from the mold 8 and the sprue 10 is attached. The sprue 10 is a sprue into which molten metal, which is a metal melted at the time of casting, is charged.

The mold molding step S24 is a step of supplying a slurry as a mold material to the outer surface of the wax mold 9 to mold the mold structure 11 (outer mold) as shown in FIG. 7.
In the mold molding step S24, the work of immersing the wax mold 9 in the slurry, sprinkling it with refractory sand, and drying it is repeated. As a result, the mold structure 11 having a predetermined thickness is formed around the wax mold 9.

The dewaxing step S25 is a step of melting the wax W by heating the mold structure 11 with pressurized steam.
In the dewaxing step S25, the mold structure 11 is heat-treated to dissolve the wax W. In the dewaxing step S25, for example, the mold structure 11 is placed inside the autoclave, and the inside of the autoclave is filled with pressurized steam (about 180 ° C.) to heat the wax mold 9 in the mold structure 11. As a result, the wax W is melted and removed from the mold structure 11.
In the dewaxing step S25, the heated wax W expands to apply pressure to the resin-integrated core 1.

The mold firing step S26 is a step of heating and firing the mold structure 11 after the wax W is removed from the mold structure 11 through the dewaxing step S25. In the mold firing step S26, for example, the mold structure 11 is heated to, for example, about 900 ° C. in a firing furnace. As a result, the water component and unnecessary components contained in the mold structure 11 are removed. Further, the mold structure 11 is cured by firing.
In the mold firing step S26, the resin structure 2 constituting the resin-integrated core 1 is melted by heat. That is, when the ambient temperature becomes equal to or higher than the melting point of the resin, the resin melts and disappears. As a result, a mold composed of the core 3 and the mold structure 11 is completed.
In the mold firing step S26, the resin structure 2 expands due to heat.

Next, a method for manufacturing a casting, in which precision casting is performed using a mold manufactured by the mold manufacturing method, will be described.
The casting manufacturing method includes a casting step of pouring hot water into a mold, a mold removing step of removing the mold, and a decore step of eluting the core 3.
The casting step is a step of preheating (for example, 800 ° C. to 900 ° C.) the mold manufactured by the mold manufacturing method and then pouring hot water into the mold. In the casting step, a molten casting material (for example, steel) is injected between the mold structure 11 and the core 3 through the opening of the mold.

The mold removing step is a step of removing the mold structure 11 after the raw material of the casting injected in the casting step is solidified. That is, when the raw material of the casting solidifies inside the mold to form a casting, the mold structure 11 is crushed and removed from the casting.

The decore step is a step of eluting the core 3 remaining in the casting. In the decore step, for example, a casting is placed inside an autoclave, and the core 3 is eluted from the casting by repeating pressurization and depressurization in a high-temperature alkaline solution.

After the decore process, finishing treatment, heat treatment, dimensional inspection, X-ray inspection, etc. are performed to complete the casting.

According to the above embodiment, the complex and fine core 3 can be formed by forming the resin structure 2 that functions as the mold of the core 3 by using the resin 3D additive manufacturing method.

Further, since the core 3 is covered with the resin structure 2, the wax W is supplied between the mold 8 and the resin-integrated core 1 in the wax mold forming step S22. It is possible to prevent the child 3 from being deformed or damaged.
Further, when the wax W heated in the dewaxing step S25 expands, it is possible to prevent the core 3 from being deformed or damaged.

Further, since the resin structure 2 has a hollow structure, the pressure applied to the core 3 can be absorbed even when the resin structure 2 expands during the mold firing step S26. That is, during the mold firing step S26, the space S of the resin structure 2 absorbs the expansion of the resin structure 2. This makes it possible to prevent the core 3 from being deformed or damaged during the mold firing step S26.
Further, by arranging the spaces S in a grid pattern, the resin structure 2 can be deformed in a well-balanced manner.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments, and includes design changes and the like within a range that does not deviate from the gist of the present invention. ..
In the above embodiment, the turbine blades have been described as an example of casting, but the present invention is not limited to this. The method for producing a resin-integrated core, the mold manufacturing method, and the resin-integrated core of the present invention can also be applied to other precision castings.

1 Resin-integrated core 2 Resin structure 2a Outer surface 2b Inner surface 3 Core 5 First wall 6 Second wall 8 Mold 9 Wax mold 10 Gate 11 Mold structure C Connecting line F Connecting surface S Space V Cavity W wax

Claims (14)

A resin structure forming process for forming a resin structure made of resin,
A curing step of forming a resin-integrated core in which the core is covered with the resin structure by supplying the slurry to the resin structure and curing the slurry is provided .
A method for manufacturing a resin-integrated core in which the resin structure is a hollow structure. The resin structure forming step is
The method for producing a resin-integrated core according to claim 1 , further comprising an inner / outer surface molding step of forming an outer surface portion forming the outer surface of the resin structure and an inner surface portion which is a molding surface forming the core. The resin structure forming step is
The method for producing a resin-integrated core according to claim 2 , further comprising a space portion forming step of defining a plurality of spaces between the outer surface portion and the inner surface portion. A resin structure forming process for forming a resin structure made of resin,
A curing step of forming a resin-integrated core in which the core is covered with the resin structure by supplying the slurry to the resin structure and curing the slurry is provided .
The resin structure forming step is
The process includes an inner / outer surface molding step of forming an outer surface portion for forming the outer surface of the resin structure and an inner surface portion which is a molding surface for forming the core.
The resin structure forming step is
A method for manufacturing a resin-integrated core, comprising a space portion forming step of defining a plurality of spaces between the outer surface portion and the inner surface portion. The method for producing a resin-integrated core according to claim 3 or 4 , wherein at least a part of the plurality of spaces is formed in a grid pattern. The method for producing a resin-integrated core according to any one of claims 1 to 5, wherein the resin structure is formed by a 3D additive manufacturing method. Wax is supplied between the mold and the resin-integrated core manufactured by the method for producing a resin-integrated core according to any one of claims 1 to 6, and the resin is used by the wax. A wax mold forming step of forming a wax mold including an integrated core, and
A mold molding process in which a mold material is supplied to the outer surface of the wax mold to mold a mold structure, and
A dewaxing step of heating the mold structure to remove the wax,
A mold manufacturing method comprising a mold firing step of removing the wax and then heating and firing the mold structure and removing the resin. A resin structure forming process for forming a resin structure made of resin,
A curing step of forming a resin-integrated core in which the core is covered with the resin structure by supplying the slurry to the resin structure and curing the slurry is provided.
The resin structure forming step is
An inner / outer surface molding step of forming an outer surface portion forming the outer surface of the resin structure and an inner surface portion which is a molding surface forming the core.
A method for producing a resin-integrated core, comprising a space portion forming step of defining a plurality of spaces by forming a wall portion between the outer surface portion and the inner surface portion. With the core
A resin structure made of resin and covering the core from the outside is provided.
The resin structure is
The outer surface that forms the outer surface and
An inner surface portion forming an inner surface, which is a molding surface forming the core,
A resin-integrated core having a plurality of spaces defined between the outer surface portion and the inner surface portion. The resin-integrated core according to claim 9 , wherein the resin structure is formed of a resin having a melting point of 190 ° C. or higher and is used for precision casting. The resin-integrated core according to claim 10 , wherein the core is a connecting surface formed of a connecting line connecting the outer surface portion and the inner surface portion, and has an exposed portion that is partially exposed. The resin-integrated core according to any one of claims 9 to 11, wherein at least a part of the plurality of spaces is arranged in a grid pattern. The resin-integrated core according to any one of claims 9 to 12 , wherein the resin structure is made of a 3D laminated molding material. With the core
A resin structure made of resin and covering the core from the outside is provided.
The resin structure has an outer surface portion forming an outer surface and
An inner surface portion forming an inner surface, which is a molding surface forming the core,
A resin-integrated core having a plurality of spaces defined by a wall portion formed between the outer surface portion and the inner surface portion.

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