JP2018164934A - Resin-integral mold core manufacturing method, mold manufacturing method, and resin-integral mold core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a core having a complex fine structure from deforming or being damaged.SOLUTION: A resin-integral mold core manufacturing method comprises a resin structure forming process S12 that forms a resin structure made of a resin and a cure process S13 that forms a resin-integral mold core whose core is covered with the resin structure by supplying a slurry to the resin structure and curing the slurry. Also, a mold manufacturing method uses a resin-integral mold core manufactured by the resin-integral mold core manufacturing method.SELECTED DRAWING: Figure 1

Description

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

For example, the blades of a gas turbine are exposed to hot working gas. Accordingly, in order to keep the temperature of the moving blade lower, the moving blade is cooled by flowing a cooling medium inside the moving blade.
An internal cooling structure is provided in the gas turbine rotor blade in order to allow the cooling medium to flow inside. For the production of such a gas turbine blade, it is common to use precision casting. When manufacturing a gas turbine rotor blade having an internal cooling structure using precision casting, a core (core) having the same shape as the flow path of the cooling medium is disposed, and the core is removed after casting ( For example, see Patent Document 1.)

  As a method for manufacturing such a core, an injection molding using a mold and a slip casting method in which molding is directly performed from a slurry are known. On the other hand, in order to improve performance, the internal cooling structure is complicated and miniaturized. As an alternative to these manufacturing methods, for example, a complex and fine core is manufactured using a molding apparatus such as a 3D (three-dimensional) printer. Resin 3D additive manufacturing has been attempted.

JP 2002-28751 A

  However, in the resin 3D additive manufacturing method, the strength may be insufficient, for example, a crack may occur in the core during wax (wax) injection molding.

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

  According to the first aspect of the present invention, a method for producing a resin-integrated core includes a resin structure forming step of forming a resin structure made of resin, and supplying the slurry to the resin structure by supplying the slurry. 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, the core is covered with the resin structure, thereby preventing the core from being deformed or damaged during wax injection molding in the casting manufacturing process. Can do.

In the method for manufacturing a resin-integrated core, the resin structure may have a hollow structure.
According to such a configuration, even when the resin structure expands during the mold baking process, the pressure applied to the core can be absorbed by the resin structure having a hollow structure. Thereby, it is possible to prevent the core from being deformed or damaged during the casting process.

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

  In the resin-integrated core manufacturing method, the resin structure forming step may include a space portion forming step that defines a plurality of spaces between the outer surface portion and the inner surface portion.

In the method for manufacturing a resin-integrated core, at least a part of the plurality of spaces may be formed in a lattice shape.
According to such a configuration, the resin structure can be deformed with a good balance.

In the method for manufacturing a resin-integrated core, the resin structure may be formed by a 3D additive manufacturing method.
According to 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 comprises a wax mold in which a wax is supplied between a mold and the resin-integrated core, and the resin-integrated core is included by the wax. Forming a wax mold, supplying a mold material to the outer surface of the wax mold to mold a mold structure, and removing the wax by heating the mold structure And after the wax is removed, the mold structure is heated and baked, and a mold baking step of removing the resin.

  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 The child can be prevented from being deformed or damaged. In addition, when the wax heated in the dewaxing process expands, the core can be prevented 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 that is made of resin and covers the core from the outside.

  In the resin-integrated core, the resin structure may be formed of a resin having a melting point of 190 ° C. or higher and 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. A plurality of spaces.

  In the resin-integrated core, the core may include an exposed portion that is a part of the connecting surface that includes a connecting line that connects 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 lattice shape.

  In the resin-integrated core, the resin structure may be made of a 3D additive manufacturing material.

  According to the present invention, since the core is covered with the resin structure, the core can be prevented from being deformed or damaged.

It is a flowchart of the manufacturing method of the resin integrated core of 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 embodiment of this invention. It is a flowchart of the manufacturing method of the casting_mold | template of embodiment of this invention. It is sectional drawing explaining the wax type | mold formation process of the casting_mold | template manufacturing method of embodiment of this invention. It is the schematic explaining the wax type | mold of embodiment of this invention. It is the schematic explaining the casting_mold | template structure of embodiment of this invention.

Hereinafter, a resin-integrated core manufacturing method, a mold manufacturing method, and a resin-integrated core according to an embodiment of the present invention will be described in detail with reference to the drawings.
The mold manufacturing method of this embodiment is a mold manufacturing method used for precision casting, for example, a method of manufacturing a mold for a gas turbine blade (casting) having a cooling medium flow passage which is an internal cooling structure. is there. The mold manufacturing method uses the resin-integrated core 1 (see FIG. 3) manufactured by the resin-integrated core manufacturing method. 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, the manufacturing method of the resin integrated core for manufacturing the 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 disposed in a portion corresponding to the cavity inside the casting, thereby suppressing the metal that becomes the casting from flowing during casting. Further, the resin structure 2 disappears in the mold baking step in the mold manufacturing method.

  As shown in FIG. 1, the resin-integrated core manufacturing method includes a slurry generation step S11 that generates a slurry that forms the core 3, a resin structure formation step S12 that forms a resin structure 2, and a slurry resin. A curing step S13 for curing the slurry by supplying it to the cavity V (see FIG. 2) of the structure 2 and a drying step S14 for drying the core 3 formed of the ceramic obtained by curing the slurry. Yes.

  The slurry generation step S11 is a step of generating a slurry that becomes the core 3 formed from ceramic by solidifying. The slurry can be generated, for example, by dissolving a dispersant, a crosslinking agent, and water in a silica material (powder).

Resin structure formation process S12 is the process of forming the resin structure 2 which consists of resin using the resin 3D layered modeling method.
In addition, as shown in FIG. 2, the resin structure forming step S <b> 12 is an inner / outer surface molding that forms an outer surface portion 2 a that forms the outer surface of the resin structure 2 and an inner surface portion 2 b that forms the inner surface of the resin structure 2. Step S12A is included. Furthermore, the resin structure forming step S12 includes a space portion forming step S12B that defines 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 layered material.
The resin 3D additive manufacturing method is a method of modeling an object having a three-dimensional shape using a molding apparatus such as a 3D (three-dimensional) printer. The 3D printer can easily form a three-dimensional shape that is difficult to form with existing technology without requiring a costly mold 8 or jig.

  In addition, as the 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 employed. The slurry additive manufacturing technique is a technique in which photo-curing or thermo-curing is generated in a limited region by laser irradiation to form a two-dimensional cross section having an arbitrary shape, and a three-dimensional shaped molded body is obtained by repeating this.

As shown in FIG. 2, the resin structure 2 is formed of resin, and includes an outer surface portion 2 a that forms an outer surface, and an inner surface portion 2 b that forms an inner surface that is a molding surface that forms a core 3 (see FIG. 3). And 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 and outer surface molding step S12A, the outer surface portion 2a and the inner surface portion 2b are molded using a resin 3D additive manufacturing method. In the inner / outer surface molding step S12A, a slurry supply port is formed by a connecting line C that connects 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 a resin having a melting point of 190 ° C. or higher. These resins are not limited to the above example, and any resin may be used as long as it has strength up to about 190 ° C. and has elasticity.

The molding surface formed by the inner surface portion 2 b has a shape that follows the core 3. In other words, the resin structure 2 is formed so that the slurry has 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 casting production.
The thickness of the inner surface portion 2b is preferably thicker than the thickness of the outer surface portion 2a. By increasing the thickness of the inner surface portion 2b, the 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 outer surface portion 2a thinner than 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 2b and the outer surface 2a of the resin structure 2. In the space portion molding step S12B, at least a space S is defined between the outer surface portion 2a and the inner surface portion 2b using a resin 3D additive manufacturing method.
The hollow structure is preferably a structure in which a plurality of spaces S are regularly arranged three-dimensionally. 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 and 6. A plurality of spaces S may be provided.

The first wall portion 5 is disposed at a predetermined interval in the first direction. The 2nd wall part 6 is arrange | positioned at predetermined intervals in the 2nd direction orthogonal to a 1st direction. The third wall portion is disposed at a predetermined interval in a third direction orthogonal to the first direction and the second direction. By arranging the space S by such a method, the resin structure 2 can be made into a lattice-like (mesh-like) hollow structure. That is, a structure in which at least a part of the space S is arranged in a lattice shape can be used.
The configuration of the space S formed inside the resin structure 2 is not limited to this, and may be a configuration in which one space S is provided without providing a wall portion. The space S may be defined only by the first wall portion 5. A plurality of spaces S may be formed by a honeycomb structure.

  The curing step S13 is a step of curing the slurry after supplying the slurry generated in the slurry generation step S11 to the cavity V of the resin structure 2. The slurry may be supplied while applying the 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 a slurry compact (core 3) is obtained. Thereby, 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 water in the silica is evaporated to dry the slurry compact (core 3). As a drying method, for example, a method of introducing a molded body into a predetermined moisture drying furnace can be employed.
The drying method is not limited to the method described above, and for example, a hot air drying method in which hot air generated by a gas burner is introduced for drying or a natural drying method in which the air is left at room temperature may be employed.

By carrying out the above steps, a resin-integrated core 1 as shown in FIG. 3 can be obtained. The resin-integrated core 1 is a structure in which a ceramic core 3 is protected by a resin structure 2 formed of resin.
As shown in FIG. 3, the core 3 of the resin-integrated core 1 has a connection surface F formed of a connection line C that connects the outer surface portion 2 a and the inner surface portion 2 b with an exposed portion 3 a 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, a mold manufacturing step S <b> 21 for manufacturing the mold 8, and wax mold formation for supplying wax W (wax) to the mold 8 on which the core 3 is set. Step S22, a wax mold assembly step S23 for assembling the wax mold 9, a mold molding process S24 for molding the mold structure 11 on the outer surface of the wax mold 9, a dewaxing process S25 for melting the wax W, and a mold is baked. A mold firing step S26.

The mold manufacturing process S21 is a process for 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 made of metal or ceramic.
As shown in FIG. 5, the wax mold forming step S <b> 22 is a process in which wax W is injection-molded into a mold 8 on which the resin-integrated core 1 is set to form a wax mold 9.

  In the wax mold forming step S <b> 22, the resin integrated core 1 is disposed 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 of the wax W has the same shape as the casting.

  In the wax mold forming step S22, the wax W to which the injection pressure has been applied is filled between the mold 8 and the resin integrated core 1, thereby applying pressure to the resin integrated core 1.

The wax mold assembling step S23 is a process for attaching the gate 10 (see FIG. 7) to the wax mold 9 and assembling it.
In the wax mold assembling step S23, the wax mold 9 is separated from the mold 8, and the gate 10 is attached. The gate 10 is a port into which a molten metal that is a metal melted during casting is poured.

The mold making step S24 is a step of forming a mold structure 11 (outer mold) as shown in FIG. 7 by supplying slurry as a mold material to the outer surface of the wax mold 9.
In the mold making step S24, the operation of immersing the wax mold 9 in the slurry, coating with refractory sand and drying is repeated. As a result, a 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 melt the wax W. In the dewaxing step S25, for example, the mold structure 11 is placed inside the autoclave, and 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, pressure is applied to the resin-integrated core 1 as the heated wax W expands.

The mold firing process S26 is a process in which the mold structure 11 is heated and fired after the wax W is removed from the mold structure 11 through the dewaxing process S25. In the mold baking step S26, for example, the mold structure 11 is heated to, for example, about 900 ° C. in a baking furnace. Thereby, the water component and unnecessary component contained in the mold structure 11 are removed. Furthermore, the mold structure 11 is cured by firing.
By the mold firing step S26, the resin structure 2 constituting the resin-integrated core 1 is melted by heat. That is, when the atmospheric temperature is equal to or higher than the melting point of the resin, the resin melts and disappears. Thereby, the casting_mold | template which consists of the core 3 and the casting_mold | template structure 11 is completed.
In the mold baking step S26, the resin structure 2 is expanded by heat.

Next, a casting manufacturing method 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 process for pouring molten metal into the mold, a mold removing process for removing the mold, and a decore process for eluting the core 3.
The casting step is a step of pouring the mold after preheating (for example, 800 ° C. to 900 ° C.) the mold manufactured by the mold manufacturing method. In the casting process, 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 removal step is a step of removing the mold structure 11 after the casting raw material injected in the casting step is solidified. That is, when the casting material is solidified into a casting inside the mold, the mold structure 11 is crushed and removed from the casting.

  The core removal step is a step of eluting the core 3 remaining in the casting. In the core removal step, for example, the casting is put into an autoclave, and the core 3 is eluted from the casting by repeating pressurization and decompression in a high-temperature alkaline solution.

  After performing the core removal process, a finishing process and a heat treatment are performed, and a casting is completed through dimensional inspection, X-ray inspection, and the like.

  According to the said embodiment, the complicated and fine core 3 can be formed by forming the resin structure 2 which functions as a type | mold of the core 3 using the resin 3D additive manufacturing method.

Further, since the core 3 is covered with the resin structure 2, when the wax W is supplied between the mold 8 and the resin-integrated core 1 in the wax mold forming step S22, the core 3 is covered. It is possible to prevent the child 3 from being deformed or damaged.
Moreover, when the wax W heated in the dewaxing step S25 expands, the core 3 can be prevented 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 baking step S26. That is, the space S of the resin structure 2 absorbs the expansion of the resin structure 2 during the mold baking step S26. Thereby, it is possible to prevent the core 3 from being deformed or damaged during the mold baking step S26.
Moreover, the resin structure 2 can be deformed in a balanced manner by arranging the spaces S in a lattice shape.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention. .
In the above embodiment, the turbine rotor blade is described as an example of the casting, but the present invention is not limited to this. The resin-integrated core manufacturing method, mold manufacturing method, and resin-integrated core of the present invention can be applied to other precision castings.

DESCRIPTION OF SYMBOLS 1 Resin-integrated core 2 Resin structure 2a Outer surface part 2b Inner surface part 3 Core 5 1st wall part 6 2nd wall part 8 Mold 9 Wax type 10 Pouring gate 11 Mold structure C Connection line F Connection surface S Space V Cavity W Wax

Claims (13)

A resin structure forming step of forming a resin structure made of resin;
A curing step of supplying a slurry to the resin structure and curing the slurry to form a resin-integrated core in which the core is covered with the resin structure. Production method.   The method for producing a resin-integrated core according to claim 1, wherein the resin structure has a hollow structure. The resin structure forming step includes
3. The resin-integrated core according to claim 1, further comprising an inner and outer surface molding step of forming 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. Manufacturing method. The resin structure forming step includes
The method for manufacturing a resin-integrated core according to claim 3, further comprising: a space portion forming step that defines 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 4, wherein at least a part of the plurality of spaces is formed in a lattice shape.   The said resin structure is modeled by 3D additive manufacturing method, The manufacturing method of the resin integrated core as described in any one of Claims 1-5 characterized by the above-mentioned. A wax is supplied between the mold and the resin-integrated core manufactured by the method for manufacturing a resin-integrated core according to any one of claims 1 to 6, and the resin is supplied by wax. A wax mold forming step for forming a wax mold including an integral core;
A mold making step of forming a mold structure by supplying a mold material to the outer surface of the wax mold;
A dewaxing step of heating the mold structure to remove the wax;
A mold manufacturing method comprising: a mold baking step of heating and baking the mold structure after removing the wax and removing the resin. With the core
A resin-integrated core comprising a resin structure made of resin and covering the core from the outside.   The resin-integrated core according to claim 8, 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 structure has an outer surface portion forming an outer surface;
An inner surface part forming an inner surface which is a molding surface forming the core;
The resin-integrated core according to claim 8 or 9, comprising a plurality of spaces defined between the outer surface portion and the inner surface portion.   The resin-integrated core according to claim 10, wherein the core has an exposed portion that is a connection surface formed of a connection line that connects the outer surface portion and the inner surface portion.   The resin-integrated core according to claim 10 or 11, wherein at least some of the plurality of spaces are arranged in a lattice pattern.   The resin-integrated core according to any one of claims 8 to 12, wherein the resin structure is made of a 3D additive manufacturing material.

Images