KR20050019998A - Method of manufacturing turbine blade and injection nozzle - Google Patents

Abstract

PURPOSE: A manufacturing method of a turbine blade and an injection nozzle is provided to manufacture the turbine blade integrally, and to improve the accuracy of the turbine blade by making the unsintered turbine blade including the core and removing the core from the turbine blade without additional post-process. CONSTITUTION: A core is manufactured to form a hollow structure inside a turbine blade(S110), and the forming mixture is manufactured by mixing and kneading raw material powder and a binder(S120). The core is placed in a mold for forming the turbine blade(S130), and the preform is manufactured by injecting the forming mixture into the mold in which the core is placed(S140). Unsintered materials are manufactured by removing the core from the perform, and the unsintered material is sintered(S150,S160). The core is composed of polypropylene resin, polyethylene resin or acrylic resin, and the binder is composed of dioctyl phthalic acid. The core is removed by dissolving the preform with the solvent.

Description

How to make turbine blades and injection nozzles {METHOD OF MANUFACTURING TURBINE BLADE AND INJECTION NOZZLE}

The present invention relates to a method for manufacturing a turbine blade and an injection nozzle, and more particularly, to a method for manufacturing a turbine blade and an injection nozzle of a complicated shape with significantly improved processability using a core.

Recently, molded articles of metal, ceramic, or plastic materials are being used not only for general industrial materials but also for electronic parts and optical fiber parts. Such advanced parts require high levels of dimensional stability and excellent physical properties, and in some cases, molding of complex shapes.

In response to these demands, recently, powder injection molding processes capable of near net shapes have been widely applied. For example, according to the powder injection molding method, a precise molding is possible by adding a binder to a metal or ceramic powder. However, there is a problem in applying the powder injection molding process in the case of a product including a complicated structure such as undercut. That is, the molded article including the undercut cannot be integrally formed using the injection molding method, and once the molded article without the undercut is manufactured, the process of additionally performing the machining process after removing the undercut portion through a complicated machining process is required. There is a feeling.

In order to solve this problem, the inventors of the present invention invented a method for manufacturing a molded body including an undercut by using a core and has filed it as a Korean Patent Application No. 10-2003-48986, and is currently continuing in the Republic of Korea Patent Office.

On the other hand, in the case of a turbine blade used as one of a plurality of blade arrangements installed in an annular flow path of a turbine working fluid, it is proposed to have various additional functions, and recently, these additional functions are effectively performed. In order to achieve this, the shape of the turbine blade is also complicated. As an example, a method of securing a cooling air flow path in a turbine blade and using limited air flowing in the air flow path with high efficiency and preventing high temperature of the blade portion has been proposed. To this end, a hollow blade is formed in the blade portion, or a slit is formed in the blade portion in the installation direction of the turbine blade. The turbine blade is made into various shapes and cooled by passing through cooling air.

For this purpose, Japanese Patent Laid-Open No. 2002-129905 discloses that a turbine blade having a hollow for an air flow path is formed by casting and then penetrated through a platform portion and a shank portion of the turbine blade to add a predetermined function. A method of additionally forming a hole called a tandem hole formed in series is formed by drill processing or electric discharge processing.

However, in the above-described prior art, since the main structure of the turbine blade is molded by casting, precision cannot be secured, and an error occurs in the thickness of each portion in the outer peripheral portion of the turbine blade, so the degree of thermal deformation according to the thickness changes. do. In addition, since the error is large, it is difficult to manufacture a turbine blade with high precision in consideration of thermal deformation and deterioration of the composition. Furthermore, after casting, an additional process by a separate machining is required, and accordingly, the manufacturing cost is high.

Lost wax is also frequently used as a manufacturing method. In the case of the lost wax method, a wax is first formed, and a gel coating is performed on the wax several times to form a mold, and then the wax is removed from the mold to form a casting mold. It requires a series of operations to introduce the material. This is very expensive because it takes a lot of time and effort.

On the other hand, in the case of injection nozzles for automobile fuel injection, fine holes are manufactured through fine drill processing, but the diameter of the drilling process is limited to about 0.08 mm and it is impossible to adjust the angle of the holes at will. Recently, various researches for improving fuel efficiency and exhaust gas reduction through complete combustion by controlling the amount of fuel injected into a combustion chamber have been conducted, but since the manufacturing process depends on precision processing, it is difficult to manufacture an optimal product. In addition, the manufacturing cost is expensive because the manufacturing cost is dependent on the precision processing, there is a technical limitation in adjusting the hole size (hole size) and direction (angle).

In order to solve the problems in manufacturing the turbine blade and the injection nozzle having a complicated structure as described above, the inventors have improved the method of manufacturing a molded article using the core invented (Korea Patent Application No. 10-2003-48986) And by optimizing the technology to satisfy the individual characteristics required for each component, there is a need to develop a manufacturing method that is easy to manufacture and also excellent characteristics of the manufactured turbine blade and injection nozzle.

Accordingly, a first object of the present invention is to provide a turbine blade manufacturing method capable of easily forming a hollow structure of a complicated shape or the like.

A second object of the present invention is to provide a method of manufacturing an injection nozzle which can easily form a plurality of fuel injection holes.

According to one embodiment of the turbine blade manufacturing method according to the present invention for achieving the first object of the present invention described above, first, by forming a core for forming a hollow structure inside the turbine blade, and kneading the raw powder and the binder Prepare the molding mixture. Subsequently, the core is inserted into a mold for forming the turbine blade, and the molding mixture is introduced into a mold in which the core is located to prepare a preform. Subsequently, the core is removed from the preform to produce a green body, and the green body is sintered to produce a turbine blade having a hollow structure.

According to one embodiment of the manufacturing method of the injection nozzle according to the present invention for achieving the second object of the present invention described above, first forming a core for the formation of the injection nozzle, the raw material powder and binder suitable as a material of the injection nozzle Kneading to prepare a molding mixture. Subsequently, the core is inserted into a mold for forming an injection nozzle, the molding mixture is put into a mold in which the core is located to prepare a preform, the core is removed from the preform to prepare a microstructure, and the microstructure is sintered to inject. Build the nozzle.

According to the present invention, a turbine blade having a complicated shape such as a hollow structure can be manufactured integrally without undergoing a separate post-processing process using a core. That is, since the turbine blades can be manufactured by removing only the cores after the core turbine blade including the core is manufactured, it is possible to manufacture turbine blades with high precision without requiring any additional process and cost.

In particular, if a turbine blade having a hollow structure is manufactured using such a manufacturing method, the turbine blade can be cooled effectively, and the weight of the turbine blade and the material cost can be reduced. In addition, complex structures such as three-dimensional honeycomb structures and ribs in the hollow portion can also be formed relatively easily by using a core, and at the same time, it is possible to maintain the strength of the turbine blades.

In addition, it is possible to prevent the degradation of precision due to the separate post-processing, it is easy to mold the thickness of the turbine blade in consideration of thermal deformation, compositional deformation, etc. that are a problem when using the turbine blade. According to this processing method, it is possible to mold a turbine blade without losing the characteristic properties, such as heat resistance, which each metal element which comprises a raw material powder has, for example.

In addition, in the case of injection nozzles for automobile engines, as in the case of the turbine blades, finer holes may be manufactured without additional post-processing in the forming step. Therefore, it is possible to reduce the manufacturing cost by simplifying the process, to overcome the limitations of the drilling process, and to form relatively fine holes, thereby improving fuel efficiency and exhaust gas reduction effect due to complete combustion.

Hereinafter, a method of manufacturing a turbine blade and a method of manufacturing an injection nozzle according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings. 1 is a flowchart illustrating an embodiment of a turbine blade manufacturing method according to the present invention.

Referring to FIG. 1, a middle core for forming a hollow structure is formed in a turbine blade (S110), and a molding mixture is manufactured (S120). And the core is placed in a mold (S130), to prepare a preform (S140). Subsequently, after removing the core from the preform (S150), it is sintered to produce a turbine blade having a hollow structure (S160).

First, in the present embodiment, the core for forming a hollow structure is formed in the turbine blade (S110). The process of forming the core will be described in detail with reference to the drawings. 2 is a cross-sectional view of a mold for forming a core for explaining an example of the forming step of the core for producing a turbine blade according to FIG.

Referring to FIG. 2, a mold for forming a core 10 having an upper mold 14 having a core molding mixture inlet 16 through which a molding mixture can be injected, and a lower mold 12 constituting the core molding unit 18 together with the upper mold Prepare. The core is molded into a predetermined shape by compression molding or injection molding by inserting a thermoplastic resin such as polypropylene resin, polyethylene resin, or acrylic resin through the core molding mixture inlet 16 of the prepared core molding die 10. When producing a core using the raw material containing polypropylene, a polyethylene resin, an acrylic resin, etc., the said core can be melt | dissolved easily with a solvent.

In addition, when the core is molded from a material having a lower melting point than that of a raw material powder and a binder described later, the core may be easily oxidized by gasification and removed by melting, and the sintering temperature during the sintering treatment may be If the temperature is set below the melting point of the raw material powder and the binder and at the same time above the melting point of the core, it can be removed even if only the core is melted by the sintering treatment.

 FIG. 3A is a plan view illustrating an example of a core manufactured using a mold illustrated in FIG. 2, and FIG. 3B is a side view illustrating the core illustrated in FIG. 3A.

3A and 3B, the core 20 manufactured by the method described above includes a fixing portion 22 and a tip portion 24. The fixing portion 22 is a portion to which the core 20 is fixed so as not to move in the turbine blade forming mold, and the tip portion 24 is a portion for forming the hollow structure of the turbine blade according to the shape of the hollow structure to be molded. Various modifications can be made.

Apart from the formation of the core, the raw material powder and the binder are kneaded to prepare a molding mixture (S120). Turbine blades or injection nozzles should not cause changes in physical properties at high temperatures and harsh conditions in actual use. The raw material powders are made of super heat-resistant materials containing metallic elements such as Ni, Cr, Al, Mo, Ti, and Zr. A super heat-resistant material is used in which a metal element such as Mn, Si, Cr, Ni, Fe, W, Zr, Ta is mixed with the material or metal element Co as a main component. And the binder is, for example, dioctyl phthalate (DiOctyl Phthalate: DOP) and the like.

The binder serves to maintain the shape after the molding until the sintered and solidified microturbine blade of the shape of the turbine blade to the mold. Further, in the molding mixture in which the binder is kneaded, the binder is melted and removed by heat during or after the subsequent sintering treatment to form a molded article composed of raw material powder only. The removal treatment point indicates a melting point of the material when the predetermined material is removed by heat, and indicates a melting point that can be dissolved by a solvent when removing by a chemical reaction. Only the predetermined material is removed from the material.

Subsequently, the core is placed in a mold for forming a turbine blade (S130), and then the molding mixture is introduced into a mold in which the core is located to prepare a preform (S140). 4 is a cross-sectional view of a turbine blade forming die 30 for explaining an example of a step of manufacturing a preform for manufacturing a turbine blade according to FIG. 1.

Referring to FIG. 4, the turbine blade forming mold 30 has an upper mold 34 and a lower mold 32 having a molding mixture inlet 36, and the turbine blade molding by the upper mold 34 and the lower mold 32. A portion 38 is formed. The fixed portion 22 of the core 20 is fixed between the upper die 34 and the lower die 32, and the tip end 24 of the core 20 is located at the turbine blade forming portion 38. The molding mixture is introduced into the turbine blade forming unit 38 in which the hollow is located, through the molding mixture inlet 36 to prepare a preform including the core.

Subsequently, the core is removed from the preform to prepare a microstructure (S150). The core 20 can be removed by dissolution treatment or heat treatment while being inserted into the preform, or by physically removing the core from the preform. Furthermore, it is also possible to transfer the external shape of the said core to the predetermined part of the preformed fine turbine blade as it is.

Specifically, the method of removing the core 20 is appropriately performed in consideration of the materials of the turbine blade and the core. When the core 20 is made of an acrylic resin having a melting point or boiling point lower than that of the raw material powder and the binder DOP, it can be easily removed by evaporation by melting or oxidizing by heat without eroding the solvent. That is, in this case, when the melting point is noted, the melting point of the acrylic resin is 180 ° C, and the melting point of the DOP is 400 ° C (since the raw material powder is composed of metal elements, the melting point is very high compared to these melting points). Accordingly, it is possible to melt and remove the acrylic resin having the lowest melting point by heat. In particular, when the sintering temperature of the sintering step described below is below the melting point of the raw material powder and above the melting point of the core powder, the core may be melted and removed through the sintering treatment without a separate core removal process. In addition, the kneaded raw material powder can utilize the characteristic peculiar to the former, for example, when the metal element of the main component is not Ni and the main component is Co. In this way, the kneaded raw material powder can be formed by using a special metal element or changing the composition ratio according to the use.

Finally, the green body is sintered to manufacture a turbine blade having a hollow structure (S160). The green body is placed in a vacuum sintering furnace and subjected to main sintering to heat to medium temperature at which paraffin and the like mixed in the molding mixture are dissolved, and to the original sintering temperature to complete the turbine blade. FIG. 5 is a perspective view illustrating a turbine blade manufactured by the method of FIG. 1.

Referring to FIG. 5, the lower portion of the turbine blade 40 has a serration portion 42 assembled in a relationship in an annular flow path such as a rotor disk, The upper portion of the toothed portion 42 has a blade-shaped platform (44), the upper portion of the platform portion 44 has a blade portion (blade) 46, the hollow inside the turbine blade 40 The structure 48 is formed.

In addition, the hollow structure 48 having various shapes may be formed by modifying the core 20 to improve strength, heat resistance, and the like of the turbine blade. 6A is a plan view showing another embodiment of the core for producing a turbine blade according to FIG. 1, and FIG. 6B is a side view for explaining the core 50 shown in FIG. 6A.

6A and 6B, the core 50 has a tip portion 54 and a fixing portion 52 integrally formed, and the tip portion 54 has an opening for forming a rib in the hollow of the turbine blade. 56 is formed. Specifically, for example, by using a core having a plurality of openings 56 in the thickness direction in the longitudinal side surface of the core 50 corresponding to the number, size, and position of the ribs to be formed in various forms in the turbine blade hollow Can form a rib. FIG. 7 is a perspective view for explaining a turbine blade manufactured by using the core shown in FIG. 6A. FIG. Referring to FIG. 7, the hollow structure of the turbine blade 60 having the teeth 62, the platform 64, and the wings 66 is a rib 68 manufactured through the rib-forming opening 56. Is formed.

  Since the ribs 68 are formed in the shape of the ribs 68 protruding from the hollow portion (air flow path) while improving the strength of the turbine blade, the cooling air is introduced into the ribs 68 when the cool air flows into the hollow portion. It is possible to cool the wing portion 66 which has been brought into direct contact, in particular high temperature. Furthermore, by forming the rib 68, it is possible to improve the cooling efficiency of the turbine blade 11.

Furthermore, it is also possible to form the three-dimensional honeycomb structure on the inner peripheral surface of the hollow part of the turbine blade which inserted the core in the metal mold | die by shape | molding the side surface part of a core in a three-dimensional honeycomb structure. FIG. 8A is a plan view showing still another embodiment of the core for manufacturing a turbine blade according to FIG. 1, and FIG. 8B is a side view for explaining the core shown in FIG. 8A. 8A and 8B, the core 70 is integrally formed with the tip portion 74 and the fixing portion 72, and the tip portion 74 forms a honeycomb shape on the hollow surface of the turbine blade. The three-dimensional honeycomb-shaped uneven | corrugated part 76 for this is formed.

In addition, it is also possible to form a protrusion (slit groove) on the side surface of the core to shape the turbine blade into a shape where the surface of the blade portion and the hollow portion penetrate through the slit groove. Of course, such a shape may be combined to form the rib structure and the three-dimensional honeycomb structure together at each predetermined portion of the turbine blade, or may be formed by combining the through hole and the three-dimensional honeycomb structure at the predetermined portion of the core. For this purpose, a plurality of middle characters may be used.

In this way, the strength reduction of the turbine blades by the hollow portion is prevented, and even when the surface temperature of the turbine blade portion becomes high, it is possible to cool the cooling air in the hollow portion through the slit groove.

In another aspect, the present invention provides a manufacturing method of the injection nozzle using the core. 9 is a flowchart illustrating an embodiment of a method of manufacturing an injection nozzle according to the present invention. 9, the core is molded (S210), and a molding mixture is prepared (S220). And the core is placed in a mold (S230), to prepare a preform (S240). Subsequently, after removing the core from the preform (S250), it is sintered to produce an injection nozzle used for, for example, fuel injection for an automobile engine (S260). The manufacturing process of the injection nozzle described above is generally similar to the manufacturing process of the turbine blade, but there are differences in the shape of the core, which will be described later.

First, the core used for molding the injection nozzle is manufactured (S210). 10 is a cross-sectional view of the core 100 for explaining an embodiment of the core for manufacturing the injection nozzle according to FIG. Referring to FIG. 10, the core 100 includes a protrusion 102 for forming a fuel injection port 112.

FIG. 11A is a plan view illustrating a method of manufacturing the injection nozzle according to the method of FIG. 9, and FIG. 11B is a plan view of the injection nozzle illustrated in FIG. 11A observed in the A direction. Referring to FIG. 11A, a fuel injection hole 112 formed by the protrusion 102 of the core 100 is formed in the preform 110 for forming the injection nozzle, and FIG. 11B, which is a plan view in the A direction thereof. For reference, it can be observed that a plurality of fuel injection holes 112 are formed in the preform 100. By controlling the number, position, angle, and thickness of the protrusions 102, an injection nozzle having a fuel injection port 112 having a desired number and size can be manufactured. In particular, an injection for an automotive engine having a fuel injection hole having a diameter of about 0.03 mm is possible. A nozzle can be manufactured easily.

The present invention will be described in more detail with reference to the following examples. However, an Example is for illustrating this invention and is not limited only to these.

EXAMPLE-Fabrication of Turbine Blades

(Molding of the middle)

First, the core having a shape corresponding to that of the hollow part in the turbine blade was molded by injection molding. To this end, a cavity was formed in a mold and an acrylic resin was injected into the mold to solidify the core.

(Preparation of Molding Mixture)

Various metal powders are mixed with Ni as a main component so that the produced turbine blades exhibit desired characteristics such as ultra heat-resistant materials and hardness (for example, density 8.795 (g / cm3) and Vickers hardness (load 10 kgf) of 376 or more). The volume ratio was Ni 72.5%, Cr 11.8%, Al 6.41%, Mo 4.52%, Ti 1.21%, Zr 0.16% to obtain a raw powder. DOP was added to the raw material powder and kneaded to form a molding mixture.

(Position of the middle)

Next, a shape corresponding to the outer shape of the turbine blade was formed by the cavity of the mold, and the core was fixed to the mold at a predetermined position of the mold.

(Manufacture of Preformed Body)

The preform (green body) of the turbine blade was obtained by press-filling and fixing the molding mixture heated through the molding mixture inlet. The green body of the turbine blade as a green body after the molding of the molding mixture was added with DOP even when taken out from the mold, and thus it was possible to maintain the shape after the molding without being sintered unless an impact or the like exceeding a predetermined size.

(Preparation of Unsintered Body)

Put the micro-aggregation into a container in a device capable of temperature control, inject a low boiling solvent into the container, seal it, and soak for about 1 hour for 1mm thickness of the middle core made of acrylic resin. It was. In other words, when the erosion of the solvent was completed in the middle, the solvent was regenerated by lowering the temperature in the apparatus to cool the solvent.

In addition, DOP is not eroded by the solvent, and the specific properties of the metal raw material powders are not lost. That is, only the middle character was completely removed to the outside of the green body by the middle removal process, and the green body was not affected by the solvent at all.

(Turbine Blade Production)

The prepared green body was put in a vacuum sintering furnace and subjected to a sintering treatment during heating to a medium temperature at which paraffin and the like mixed in a raw material mixture were dissolved, and a main sintering treatment for heating to the original sintering temperature.

The forming method described above makes it easy and accurate because the outer core shape of the core can be transferred to the shape of the hollow portion of the turbine blade even if the shape is more complicated than a turbine blade having no hollow portion such as a turbine blade having a hollow portion. It is possible to shape the turbine blade better.

That is, even in the case of a shape requiring machining or normal machining, it is possible to easily mold using only the molding method of this embodiment.

According to the present invention, a turbine blade having a complicated shape such as a hollow structure can be manufactured integrally without undergoing a separate post-processing process using a core. That is, since the turbine blades can be manufactured by removing only the cores after the core turbine blade including the core is manufactured, it is possible to manufacture turbine blades with high precision without requiring any additional process and cost.

In particular, by manufacturing a turbine blade having a hollow structure using such a manufacturing method, it is possible to effectively cool the turbine blade, it is possible to achieve a reduction in the weight of the turbine blade, material costs. In addition, complex structures such as three-dimensional honeycomb structures and ribs in the hollow portion can also be formed relatively easily by using a core, and at the same time, it is possible to maintain the strength of the turbine blades.

In addition, it is possible to prevent the deterioration of precision due to separate post-processing, and it is easy to mold the thickness of the turbine blade in consideration of thermal deformation, composition deformation, etc., which are a problem when using the turbine blade. According to this processing method, it is possible to form a turbine blade without losing the characteristic properties of each of the metal elements constituting the raw material powder, for example, heat resistance and the like.

In addition, in the case of injection nozzles for automobile engines, as in the case of the turbine blades, finer holes may be manufactured without additional post-processing in the forming step. Therefore, it is possible to reduce the manufacturing cost by simplifying the process, to overcome the limitations of the drilling process, and to form relatively fine holes, thereby improving fuel efficiency and exhaust gas reduction effect due to complete combustion.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

1 is a flow chart illustrating an embodiment of a turbine blade manufacturing method according to the present invention.

2 is a cross-sectional view of a mold for forming a core for explaining an example of the forming step of the core for producing a turbine blade according to FIG.

FIG. 3A is a plan view showing an embodiment of a core manufactured using a mold shown in FIG. 2. FIG.

3B is a side view showing the middle core shown in FIG. 3A,

4 is a cross-sectional view of a mold for forming a turbine blade for explaining an example of a step of manufacturing a preform for manufacturing a turbine blade according to FIG. 1.

FIG. 5 is a perspective view illustrating a turbine blade manufactured by the method of FIG. 1.

Figure 6a is a plan view showing another embodiment of the core for manufacturing the turbine blade according to FIG.

FIG. 6B is a side view for explaining the middle core shown in FIG. 6A. FIG.

FIG. 7 is a perspective view for explaining a turbine blade manufactured by using the core shown in FIG. 6A. FIG.

 8A is a plan view showing another embodiment of the core for manufacturing the turbine blade according to FIG.

FIG. 8B is a side view for explaining the middle core shown in FIG. 8A. FIG.

9 is a flowchart illustrating an embodiment of a method of manufacturing an injection nozzle according to the present invention.

10 is a cross-sectional view of the core for explaining an embodiment of the core for manufacturing the injection nozzle according to FIG.

FIG. 11A is a plan view illustrating an injection nozzle manufactured according to the method of FIG. 9.

FIG. 11B is a plan view of the injection nozzle shown in FIG. 11A observed in the A direction. FIG.

Brief description of the main parts of the drawing

10: middle metal mold 12, 32: lower mold

14, 34: upper box 16: core molding mixture inlet

18: Middle core part 20, 50, 70: Middle core for forming hollow structure

22, 52, 72: fixed part 24, 54, 74: tip part

30 turbine blade forming mold 36 molding mixture inlet

38: molding mixture 40, 60: turbine blade

42, 62: tooth 44, 64: platform

46, 66: wing portion 48: hollow structure

56: opening for rib formation 68: rib

76: honeycomb concave-convex portion 100: the core for forming the injection nozzle

102: protrusion 110: preform

112: fuel nozzle

Claims (10)

Forming a core for forming a hollow structure in the turbine blade; Kneading the raw powder and the binder to prepare a molding mixture; Positioning the core in a mold for forming a turbine blade; Preparing a preform by injecting the molding mixture into a mold in which the core is located; Preparing a green body by removing the core from the preform; And Method of manufacturing a turbine blade having a hollow structure comprising the step of sintering the green body. The turbine blade manufacturing method according to claim 1, wherein the core is a polypropylene resin, a polyethylene resin, or an acrylic resin. The method of claim 1, wherein the binder is dioctyl phthalate. The method of manufacturing a turbine blade according to claim 1, wherein the removal of the core is performed by dissolving the preform with a solvent. The method of claim 1, wherein the removal of the core is performed by heating the preform. The method of manufacturing a turbine blade according to claim 1, wherein the core includes an opening for forming a rib in the hollow of the turbine blade. The method of manufacturing a turbine blade according to claim 1, wherein the core includes a honeycomb uneven portion for forming a honeycomb shape on the hollow surface of the turbine blade. The method of claim 1, wherein the core includes a protrusion for forming a slit penetrating the hollow surface of the turbine blade and the outer surface of the turbine blade. Shaping the core; Kneading the raw powder and the binder to prepare a molding mixture; Positioning the core in a mold for forming an injection nozzle; Preparing a preform by injecting the molding mixture into a mold in which the core is located; Removing the core from the preform to produce a green body; And Method of manufacturing an injection nozzle comprising the step of sintering the green body. 10. The method of claim 9, wherein the core includes a plurality of protrusions for forming a fuel injection hole in the nozzle.