A guide blade ceramic core positioning method based on core head prefabricated tapered hole and its application

Abstract

The present invention relates to a guide blade ceramic core based on a core head prefabricated tapered hole, a positioning method and an application thereof, belonging to the technical field of precision casting of hollow turbine blades of aircraft engines; the guide blade ceramic core comprises a guide blade ceramic core and core heads located at both ends thereof, and the end faces of the core heads are provided with prefabricated tapered holes for positioning the guide blade ceramic core in the mold. The positioning method comprises the following steps: designing the geometric structure of the prefabricated tapered hole of the core head of the guide blade ceramic core; preparing the guide blade ceramic core with the prefabricated tapered hole of the core head; polishing and shaping the prefabricated tapered hole of the core head; designing and processing the structure of the core head movable block of the guide blade wax mold; and performing press-molding matching and positioning on the guide blade ceramic core with the prefabricated tapered hole of the core head. The positioning method of the present invention limits the spatial freedom of the ceramic core in the mold, solving the technical problem of poor positioning accuracy and stability of the guide blade ceramic core inside the wax mold in the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision casting of hollow turbine blades of aircraft engines, and in particular relates to a ceramic core of a guide blade based on a prefabricated tapered hole of a core head, a positioning method and an application thereof. Background Art

[0002] Turbine guide vanes are one of the key hot-end components in aircraft engines, and the manufacturing accuracy of the hollow guide vane structure determines the cooling performance and mechanical properties of the blade during service. Guide vanes are usually manufactured using the investment casting process, which includes three main steps: investment wax preparation, shell mold preparation, and casting preparation. In the multi-stage investment casting process, the key to improving the manufacturing accuracy of hollow guide vanes lies in the preparation of high-precision blade wax patterns. Since the cavity shape of the wax mold is fixed, the surface and wall thickness accuracy of the hollow wax mold depend on the spatial position of the internal ceramic core in the mold. Therefore, how to ensure the high-precision and high-stability positioning of the guide vane ceramic core inside the wax mold is a key bottleneck problem that needs to be solved urgently.

[0003] As a stator blade, a turbine guide vane requires a ceramic core with a core head extension to ensure continuous cooling airflow through the upper and lower edge plates of the blade. The blade section of the core is suspended within the wax mold cavity to form a continuous hollow cooling channel, while the core head is embedded in the mold's concave movable block to position the core. If the concave movable block at the core head of the ceramic core is machined using a zero-allowance method, the core head and the concave structure of the movable block will not fit smoothly due to manufacturing errors, which can seriously lead to fracturing of the ceramic core during mold closing. If the machining allowance at the concave structure is increased, the ceramic core will be in a clearance fit within the wax mold, resulting in an unstable positioning surface and excessive freedom. This can easily lead to positional deviations after being impacted by the wax material during the wax mold preparation process, making it impossible to meet the required wall thickness accuracy requirements for the turbine guide vane.

[0004] In the prior art, there are methods for positioning the ceramic core of a turbine blade within a wax mold cavity. One method involves using locking bolts to secure and position the ceramic core. This involves providing positioning holes within the effective length, width, and height of the mold cavity, and providing bolts within the positioning holes with adjustable extension to secure the ceramic core within the mold cavity. This method allows for adjustment of the ceramic core within the mold. However, since the contact points between the bolts and the ceramic core are mostly located within the blade section of the wax mold cavity, this results in indentations on the surface of the pressed wax mold caused by the bolts. Production personnel are required to perform subsequent wax refilling and mold repair on the molded wax mold, which results in additional mold repair processes and potential risks of wax mold deformation. Therefore, in order to fully position the ceramic core within the mold and ensure the integrity of the wax mold blade portion, it is urgent to explore new methods for positioning the ceramic core of the guide vane within the wax mold. Summary of the Invention

[0005] Technical issues to be solved:

[0006] In order to avoid the shortcomings of the prior art, the present invention provides a guide vane ceramic core based on a core head prefabricated tapered hole, a positioning method and an application thereof. The method first designs an inner concave tapered hole of a specific geometric structure based on the core head shape of the guide vane ceramic core, and re-processes the shape of the movable block of the ceramic core pressing mold. A hot pressing process is used to prepare the ceramic core with the core head prefabricated tapered hole. A processing program is compiled according to the spatial position and depth of the core head prefabricated tapered hole. A CNC machine tool and a special diamond grinding head are used to perform shape-repair processing on the prefabricated tapered hole of the core head of the guide vane ceramic core. The polished inner concave tapered hole is the ceramic core core head prefabricated tapered hole. Further, according to the shape of the special diamond grinding head, a process boss of the same size is designed on the core head movable block of the guide vane wax mold. A CNC processing program is compiled according to the geometric structure of the process boss. A CNC machine tool and a carbide ball end milling cutter are used for processing to realize the processing of the assembly movable block inside the wax mold. When pressing the guide vane wax mold, the ceramic core with the prefabricated tapered hole after fine-tuning is assembled with the process boss in the mold movable block. The positioning method of the present invention limits the spatial freedom of the ceramic core in the mold, solving the technical problems of poor positioning accuracy and stability of the guide vane ceramic core inside the wax mold in the prior art.

[0007] The technical solution of the present invention is: a guide blade ceramic core based on a core head prefabricated tapered hole, characterized in that it includes a guide blade ceramic core and core heads located at both ends thereof, and the end faces of the core heads are provided with prefabricated tapered holes for positioning the guide blade ceramic core in a mold.

[0008] A further technical solution of the present invention is that the taper of the prefabricated tapered hole is set to 3° to 5°, and the depth of the prefabricated tapered hole is set to 1 / 2 to 2 / 3 of the total height of the core head and is not less than 2 mm.

[0009] A method for positioning a guide vane ceramic core based on a prefabricated tapered hole in a core head, characterized by the following specific steps:

[0010] Design the geometric structure of the prefabricated tapered hole in the ceramic core head of the guide vane;

[0011] Prepare the ceramic core of the guide vane with a prefabricated tapered hole in the core head;

[0012] Grinding and reshaping the prefabricated tapered hole of the core head;

[0013] Design and process the structure of the core block of the guide vane wax mold;

[0014] The ceramic core of the guide vane with a prefabricated tapered hole in the core head is pressed and matched to position.

[0015] A further technical solution of the present invention is: the geometric structure design method of the prefabricated tapered hole of the guide vane ceramic core head is:

[0016] Determine the axis point of the prefabricated tapered hole of the core head;

[0017] Assume that the end faces of the guide vane ceramic core on both sides are horizontal sections parallel to the XY plane, and the geometric center of gravity of the end face contours of the two sides of the core head are used as the axis points of the prefabricated tapered holes of the two sides of the core head;

[0018] Determine the radius of the prefabricated tapered hole of the core head;

[0019] The geometric center of gravity of the core head end face contour is the center of the circle, and the radius is 1 / 2 to 2 / 3 of the minimum inscribed circle radius of the core head end face contour boundary line where the circle center is located;

[0020] Determine the geometric structure model of the core head prefabricated tapered hole;

[0021] The Z axis of the modeling coordinate system is used as the axis centerline of the core head prefabricated tapered hole. The taper of the prefabricated tapered hole is 3° to 5°, the depth is set to 2 to 5 mm, and the edge of the tapered hole is chamfered to obtain the geometric structure model of the core head prefabricated tapered hole.

[0022] A further technical solution of the present invention is: the method for preparing the guide blade ceramic core with a core head prefabricated tapered hole is:

[0023] Firstly, according to the geometric structure model of the prefabricated tapered hole of the core head, a process boss with a complementary structure is machined at the corresponding position of the core head movable block of the ceramic core pressing mold; then, the ceramic core of the guide vane is prepared by the hot pressing molding method.

[0024] A further technical solution of the present invention is: the method for preparing the ceramic core of the guide vane is:

[0025] Green blank pressing: The processed ceramic core pressing mold is closed and moved to the injection molding machine. Silicon oxide-based ceramic slurry is selected as the raw material, and the process parameters are set. The wet ceramic core green blank is obtained by hot pressing process;

[0026] Sintering treatment: the wet ceramic core blank is placed in a sandbox and then placed in a roasting furnace for sintering, and roasting parameters are set to obtain a sintered ceramic core;

[0027] Strengthening treatment: The sintered ceramic core is strengthened at high temperature with ethyl silicate hydrolyzate, and the high temperature strengthened ceramic core is strengthened at room temperature with a mixed solution of polyamide, epoxy resin and acetone to obtain a guide blade ceramic core with a prefabricated tapered hole in the core head.

[0028] A further technical solution of the present invention is: a method for grinding and shaping the prefabricated tapered hole of the core head,

[0029] Preparation of special diamond grinding heads;

[0030] The special diamond grinding head has the same structure as the prefabricated tapered hole of the core head, and its bottom circle diameter is 0.2 to 0.5 mm larger than the prefabricated tapered hole. The tolerance grade of the grinding head size is not lower than IT7.

[0031] Polishing and shaping;

[0032] The guide blade ceramic core is installed on the grinding machine with the stacking axis direction as the Z axis; the spindle axis of the special diamond grinding head is aligned with the theoretical axis center line position of the prefabricated tapered hole, the feed rate and spindle speed are set, and the ceramic core prefabricated tapered hole is overall ground and reshaped.

[0033] A further technical solution of the present invention is: designing a processing boss on the core head block of the guide blade wax mold, and the processing boss is consistent with the structural size of the special diamond grinding head; using a three-axis CNC machine tool to process the processing boss of the core head block of the guide blade wax mold, and selecting a carbide milling cutter with a tool ball head radius of 0.5 mm.

[0034] A further technical solution of the present invention is: a method for press-forming matching and positioning of a guide vane ceramic core with a core head prefabricated tapered hole is to combine and assemble the core head movable block of the guide vane wax mold with the remaining movable blocks of the wax mold. When in use, the core head movable block of the guide vane wax mold is moved out to the mold-parting state through the guide rail structure, and the core head at one end of the guide vane ceramic core with a core head prefabricated tapered hole is embedded in the core head movable block of the wax mold. The core head at the other end is moved smoothly along the guide rail to the corresponding core head movable block, so that the process boss of the core head movable block and the core head prefabricated tapered hole are gradually matched to the mold-closing state, thereby realizing press-forming matching and positioning of the guide vane ceramic core.

[0035] A guide vane ceramic core positioning method based on a prefabricated tapered hole in a core head is applied in the manufacture of turbine guide vanes, thereby improving the manufacturing accuracy of the turbine guide vanes.

[0036] Beneficial effects

[0037] The beneficial effects of the present invention are as follows: the present invention designs initial prefabricated tapered holes of appropriate size at the end faces of the extended sections of the core heads on both sides of the guide vane ceramic core, uses a hot press to prepare the corresponding ceramic core blank, and performs sintering, strengthening and other pretreatments to obtain a guide vane ceramic core with a core head prefabricated hole, installs the ceramic core on a grinding machine, adjusts the processing posture and aligns the axis, uses a special diamond grinding head to grind and shape the initial tapered hole of the core head, and obtains a core head prefabricated tapered hole with good consistency in hole shape and manufacturing accuracy. According to the structural shape of the prefabricated tapered hole, a positioning cone that meets the assembly accuracy requirements is machined in the mold block where the wax mold and the guide vane core head are embedded. When the ceramic core is installed inside the wax mold, the prefabricated tapered hole of the ceramic core head on one side is first embedded in the positioning cone of the fixed block inside the wax mold to achieve assembly combination, and then the mold sliding block corresponding to the core head on the other side of the ceramic core is aligned and moved to close the mold, thereby achieving accurate and stable positioning of the guide vane ceramic core inside the wax mold. In the present invention, the positioning surfaces of the ceramic core head are all precision-machined surfaces, which can significantly improve the assembly accuracy and positioning accuracy of the guide vane ceramic core inside the wax mold.

[0038] The guide blade ceramic core positioning method described in the present invention was compared with the existing method using a motion simulation method. The test results showed that under the same external force load, the three-dimensional movement of the guide blade ceramic core using the existing method was: +0.1521mm (X direction), +0.1273mm (Y direction), +0.0347mm (Z direction); the three-dimensional movement of the guide blade ceramic core using the method described in the present invention was: +0.0152mm (X direction), +0.0149mm (Y direction), +0.0130mm (Z direction). This proves that the guide blade ceramic core can be more stably positioned inside the pressing mold, which helps to improve the manufacturing accuracy of the guide blade wax mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The present invention is a flow chart of a method for positioning a ceramic core of a guide vane based on a prefabricated tapered hole in a core head.

[0040] Figure 2 It is a schematic diagram of the geometric structure of the prefabricated tapered hole in the ceramic core head of the guide blade ceramic core positioning method based on the prefabricated tapered hole in the core head of the present invention.

[0041] Figure 3 It is a schematic diagram of the geometric structure of the core head movable block of the ceramic core pressing mold in the guide blade ceramic core positioning method based on the core head prefabricated tapered hole of the present invention.

[0042] Figure 4 It is a schematic diagram of the geometric structure of a special diamond grinding head in the guide blade ceramic core positioning method based on the prefabricated tapered hole in the core head of the present invention.

[0043] Figure 5It is a schematic diagram of the assembly of the ceramic core and the pressing mold in the guide blade ceramic core positioning method based on the prefabricated tapered hole in the core head of the present invention.

[0044] Explanation of the accompanying symbols: 1. Prefabricated tapered hole of the first core head, 2. Prefabricated tapered hole of the second core head, 3. Special diamond grinding head, 4. Ceramic core of the guide blade, 5. Loose piece of the core head of the first mold, 6. Loose piece of the core head of the second mold, 7. Prefabricated tapered hole of the core head. DETAILED DESCRIPTION

[0045] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0046] Based on the defects in the prior art that the ceramic core of the guide vane cannot be fully positioned in the mold and the wax mold blade part cannot be completely formed, the present invention provides a ceramic core of the guide vane based on a prefabricated tapered hole in the core head and a positioning method. The method sequentially comprises the following processes: determining the axis centerline position of the prefabricated tapered hole at the core head end faces on both sides of the guide vane ceramic core, determining the geometric parameters of the prefabricated tapered hole in the ceramic core head according to the structural characteristics and geometric shape of the guide vane ceramic core head, and generating a tapered hole model according to the tapered hole axis position and tapered hole shape parameters; designing the core head cavity shape of the ceramic core pressing mold, and preparing the guide vane ceramic core with the core head prefabricated tapered hole by adopting a hot pressing process; installing the guide vane ceramic core in a mechanical grinding device, and using a special diamond grinding head to grind the prefabricated tapered hole of the sintered ceramic core to obtain a ceramic core with a finely trimmed core head; designing and machining a process boss in the core head movable block of the guide vane ceramic core corresponding to the wax mold mold, and when pressing the guide vane wax mold, assembling the finely trimmed ceramic core with the prefabricated tapered hole with the process boss in the mold movable block and restricting the spatial freedom of the ceramic core in the mold, thereby achieving high-precision positioning of the guide vane ceramic core in the wax mold mold.

[0047] The positioning surfaces of the ceramic core head in the present invention are all finely machined surfaces, which can significantly improve the assembly accuracy and positioning accuracy of the guide vane ceramic core inside the wax mold, and are of great significance to the production and processing of high-quality guide vane wax molds.

[0048] Example 1

[0049] The specific steps of the guide vane ceramic core positioning method based on the prefabricated tapered hole in the core head in this embodiment are as follows:

[0050] Step 1: Design the geometric structure of the prefabricated tapered hole of the ceramic core head of the guide vane;

[0051] The end faces of the guide vane ceramic core 4 are horizontal cross-sections parallel to the XY plane. Using UG modeling software, the geometric centers of gravity A1 and A2 of the core end face contours on both sides of the ceramic core are determined as the axis points of the core head prefabricated tapered hole 10. With A1 and A2 as the centers, and the radius 1 / 2 to 2 / 3 of the minimum inscribed circle radius from A1 and A2 to the core head contour boundary as the centerline, and the Z axis of the modeling coordinate system as the axis of the tapered hole, the taper is 3° to 5°, the hole depth is set to 2 to 5 mm, and the edges of the tapered hole are rounded to 0.3 to 0.5 mm.

[0052] Step 2: Preparation of ceramic core of guide vane with prefabricated tapered hole in the core head;

[0053] The ceramic core 4 of the guide blade is formed by a hot injection molding process, and the specific steps are as follows:

[0054] (1) According to the three-dimensional model of the prefabricated tapered hole 1 of the first core head, a process boss of the same shape is machined at the corresponding position of the core head movable block of the ceramic core pressing mold;

[0055] (2) Green blank pressing: The processed ceramic core pressing mold is closed and moved to the C-type injection molding machine for ceramic core wet green blank pressing. Silicon oxide-based ceramic slurry is selected as the raw material, the slurry temperature is 105℃, the injection pressure is 5.0~5.5Mpa, and the injection time is 6~9s.

[0056] (3) Sintering treatment: The wet ceramic core is placed in a sandbox and then placed in a roasting furnace. The roasting temperature is set at 1100-1400°C and the sintered ceramic core is obtained after a cycle roasting time of 20-22 hours.

[0057] (4) Strengthening treatment: The sintered ceramic core is strengthened at high temperature with ethyl silicate hydrolyzate, and then strengthened at room temperature with a mixed solution of polyamide, epoxy resin and acetone.

[0058] Step 3: Grinding and shaping the prefabricated tapered hole of the ceramic core head of the guide vane;

[0059] A special diamond grinding head 3 is prepared, whose geometric shape is similar to the prefabricated tapered hole 7 of the guide blade ceramic core 4. The bottom circle diameter is slightly larger than the prefabricated tapered hole (about 0.2-0.5 mm), the taper and hole depth parameters remain unchanged, and the tolerance grade of the grinding head size is not lower than IT7.

[0060] The guide blade ceramic core 4 is installed on the grinding machine with the stacking axis direction as the Z axis; the spindle axis of the diamond grinding head 8 is aligned with the theoretical axis center line position of the prefabricated tapered hole, the feed rate and spindle speed are set, and the ceramic core prefabricated tapered hole is overall ground and reshaped.

[0061] Step 4: Structural design and processing of the guide vane wax mold core head movable block process boss;

[0062] A process boss is designed on the movable block that matches the guide blade wax mold and the ceramic core head. The size and structure of the boss are consistent with the grinding surface of the special diamond grinding head 3 described in step three. The process boss is processed on a three-axis CNC machine tool. According to the size of the boss, a CNC machining program is compiled, and a carbide milling cutter with a tool ball head radius of 0.5 mm is selected for processing.

[0063] Step 5: Pressing and matching positioning method of the guide blade ceramic core with prefabricated tapered hole in the core head

[0064] The core head movable block processed in step 4 is combined and assembled with the other movable blocks of the wax mold pressing mold. When in use, the core head movable block is moved out to the parting state through the guide rail structure, and one end of the guide vane blade ceramic core with the core head prefabricated hole is embedded in the core head movable block of the pressing mold. The corresponding movable block of the core head on the other side is moved smoothly along the guide rail, so that the process boss and the core head prefabricated tapered hole 7 are gradually matched to the closing state, thereby realizing the pressing matching positioning of the guide vane ceramic core 4.

[0065] Example 2

[0066] To further illustrate the advantages of the positioning method of the present invention in the positioning of guide vane ceramic cores during press forming, a motion simulation method is used in this example to compare the positioning method of the guide vane ceramic cores of the present invention with the existing method. The simulation results record the positional movement of the guide vanes within the wax mold cavity under the same load. The specific steps are as follows:

[0067] Step 1: Motion Simulation Modeling

[0068] In the "Modeling" module of NX10.0 software, models of guide vane ceramic cores with / without prefabricated tapered holes in the core head are established respectively. Based on the geometric shape of the core head of the guide vane ceramic core, mold core head movable blocks with / without process bosses are established. Except for the area of ​​the prefabricated tapered holes in the core head, the gap between the outer surface of the core head of the guide vane ceramic core and the inner surface of the mold core head movable block is set to 0.2 mm.

[0069] Step 2: Motion simulation parameter settings

[0070] Load the motion simulation models described in step 1 into the "Motion Simulation" module of NX10.0 software. Define the components corresponding to the first mold core block 5, the second mold core block 6, and the guide vane ceramic core 4 as linkage mechanisms. Set the components of the first mold core block 5 and the second mold core block 6 as fixed linkage kinematic pairs. Define 3D contacts between the guide vane ceramic core 4 and the first mold core block 5, and between the components corresponding to the guide vane ceramic core 4 and the second mold core block 6. Finally, add an along-vector force object to the linkage mechanism corresponding to the guide vane ceramic core 4 to simulate the force load exerted by the wax on the guide vane ceramic core during wax injection. Set the load direction and magnitude to 50N in the +X direction, 50N in the +Y direction, and 10N in the +Z direction.

[0071] Step 3: Define the solution and record the motion results

[0072] The upper limit of the guide ceramic core manufacturing tolerance is set to 0.2 mm, which means the theoretical gap between the guide vane ceramic core 4 and the core head movable block is 0.2 mm. The solution type is defined as dynamic analysis, with an analysis time of 1.5 seconds, a number of steps of 1000, and the gravity direction set to the -Z direction. The three-dimensional motion of the connecting rod corresponding to the guide vane ceramic core 4 is retrieved from the solution results and the results are recorded in Table 1.

[0073] Table 1

[0074]

[0075] The guide blade ceramic core positioning method described in the present invention was compared with the existing method using a motion simulation method. The test results show that under the same external force load, the three-dimensional movement of the guide blade ceramic core using the existing method is: +0.1521mm (X direction), +0.1273mm (Y direction), +0.0347mm (Z direction); the three-dimensional movement of the guide blade ceramic core using the method described in the present invention is: +0.0152mm (X direction), +0.0149mm (Y direction), +0.0130mm (Z direction).

[0076] The present embodiment provides a guide blade ceramic core positioning method based on a prefabricated tapered hole in a core head, which is applied to the manufacture of turbine guide blades, thereby improving the manufacturing accuracy of the turbine guide blades.

[0077] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A method for positioning a guide vane ceramic core based on a prefabricated tapered hole in a core head, characterized by: The guide vane ceramic core based on the core head prefabricated tapered hole comprises a guide vane ceramic core and core heads located at both ends thereof, wherein the end surfaces of the core heads are provided with prefabricated tapered holes for positioning the guide vane ceramic core in the mold; The specific steps of the positioning method are as follows: Design the geometric structure of the prefabricated tapered hole in the ceramic core head of the guide vane; Prepare the ceramic core of the guide vane with a prefabricated tapered hole in the core head; Grinding and reshaping the prefabricated tapered hole of the core head; Design and process the structure of the core block of the guide vane wax mold; Perform press-forming matching and positioning on the ceramic core of the guide vane with prefabricated tapered hole on the core head; The geometric structure design method of the prefabricated tapered hole of the guide vane ceramic core head is as follows: Determine the axis point of the prefabricated tapered hole of the core head; Assume that the end faces of the guide vane ceramic core on both sides are horizontal sections parallel to the XY plane, and the geometric center of gravity of the end face contours of the two sides of the core head are used as the axis points of the prefabricated tapered holes of the two sides of the core head; Determine the radius of the prefabricated tapered hole of the core head; The geometric center of gravity of the core head end face contour is the center of the circle, and the radius is 1 / 2 to 2 / 3 of the minimum inscribed circle radius of the core head end face contour boundary line where the circle center is located; Determine the geometric structure model of the core head prefabricated tapered hole; The Z axis of the modeling coordinate system is used as the axis centerline of the core head prefabricated tapered hole. The taper of the prefabricated tapered hole is 3° to 5°, the depth is set to 2 to 5 mm, and the edge of the tapered hole is chamfered to obtain the geometric structure model of the core head prefabricated tapered hole.

2. The method for positioning a guide vane ceramic core based on a prefabricated tapered hole in a core head according to claim 1, characterized in that: The taper of the prefabricated tapered hole is set to 3° to 5°, and the depth of the prefabricated tapered hole is set to 1 / 2 to 2 / 3 of the total height of the core head and is not less than 2 mm.

3. The method for positioning a guide vane ceramic core based on a prefabricated tapered hole in a core head according to claim 1, characterized in that: The method for preparing the guide blade ceramic core with a core head prefabricated tapered hole is as follows: Firstly, according to the geometric structure model of the prefabricated tapered hole of the core head, a process boss with a complementary structure is machined at the corresponding position of the core head movable block of the ceramic core pressing mold; then, the ceramic core of the guide vane is prepared by the hot pressing molding method.

4. The method for positioning a guide vane ceramic core based on a prefabricated tapered hole in a core head according to claim 3, characterized in that: The method for preparing the guide blade ceramic core is: Green blank pressing: The processed ceramic core pressing mold is closed and moved to the injection molding machine. Silicon oxide-based ceramic slurry is selected as the raw material, and the process parameters are set. The wet ceramic core green blank is obtained by hot pressing process; Sintering treatment: the wet ceramic core blank is placed in a sandbox and then placed in a roasting furnace for sintering, and roasting parameters are set to obtain a sintered ceramic core; Strengthening treatment: The sintered ceramic core is strengthened at high temperature with ethyl silicate hydrolyzate, and the high temperature strengthened ceramic core is strengthened at room temperature with a mixed solution of polyamide, epoxy resin and acetone to obtain a guide blade ceramic core with a prefabricated tapered hole in the core head.

5. The method for positioning a guide vane ceramic core based on a prefabricated tapered hole in a core head according to claim 4, characterized in that: The grinding and shaping method of the prefabricated tapered hole of the core head, Preparation of special diamond grinding heads; The special diamond grinding head has the same structure as the prefabricated tapered hole of the core head, and its bottom circle diameter is 0.2 to 0.5 mm larger than the prefabricated tapered hole. The tolerance grade of the grinding head size is not lower than IT7. Polishing and shaping; The guide blade ceramic core is installed on the grinding machine with the stacking axis direction as the Z axis; the spindle axis of the special diamond grinding head is aligned with the theoretical axis center line position of the prefabricated tapered hole, the feed rate and spindle speed are set, and the ceramic core prefabricated tapered hole is overall ground and reshaped.

6. The method for positioning a guide vane ceramic core based on a prefabricated tapered hole in a core head according to claim 5, characterized in that: Designing a processing boss on the core head movable block of the guide vane wax mold, wherein the processing boss has the same structural dimensions as the special diamond grinding head; A three-axis CNC machine tool is used to machine the process boss of the core head movable block of the guide vane wax mold, and a carbide milling cutter with a tool ball head radius of 0.5 mm is selected.

7. The method for positioning a guide vane ceramic core based on a prefabricated tapered hole in a core head according to claim 6, characterized in that: The method for press-forming matching and positioning of the guide vane ceramic core with a core head prefabricated tapered hole is to combine and assemble the core head movable block of the guide vane wax mold with the remaining movable blocks of the wax mold. When in use, the core head movable block of the guide vane wax mold is moved out to the mold-parting state through the guide rail structure, and the core head at one end of the guide vane ceramic core with a core head prefabricated tapered hole is embedded in the core head movable block of the wax mold. The core head at the other end is moved smoothly along the guide rail to the corresponding core head movable block, so that the process boss of the core head movable block and the core head prefabricated tapered hole are gradually matched with the core head prefabricated tapered hole to the mold closing state, thereby realizing press-forming matching and positioning of the guide vane ceramic core.

8. A guide blade ceramic core positioning method based on a core head prefabricated tapered hole as claimed in any one of claims 1 to 7 is applied to the manufacture of turbine guide blades, thereby improving the manufacturing accuracy of the turbine guide blades.

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