CN117483664B - A method for splicing an annular ceramic core including blades - Google Patents

Abstract

The present invention discloses a method for splicing an annular ceramic core including blades, and relates to the field of structural design and application technology of ceramic core splicing. The specific steps of the splicing method of annular ceramic core including blades are as follows: step one, dividing the annular integral core into a plurality of split cores of the same size; step two, setting the contact surface and free surface of the split core; step three, positioning and installing the split core; with the development of engine technology, the demand for large and complex casing castings has increased, and the number of annular ceramic core structure products has increased piece by piece. The splicing method of annular ceramic core including blades can be further extended to the production of casing products with similar structures, with a wide range of applications, and improving product qualification rate and production efficiency.

Description

A method for splicing an annular ceramic core including blades

Technical Field

The invention relates to the technical field of structural design and application of ceramic core splicing, and in particular provides a splicing method of an annular ceramic core including blades.

Background Art

Complex inner cavity castings are formed by ceramic cores. The number of ceramic cores is generally 1, and some may reach multiple, but generally less than 5. The core size is generally less than 150mm, and the core is generally a rectangular structure. If there are multiple cores, the cores exist independently, and each core is positioned by the mold. The cores are not in direct contact with each other, and there is no positioning relationship between the cores. There is only a relative size tolerance relationship, and the tolerance is the free tolerance of the casting.

Castings containing ceramic cores are generally blades, and the inner cavity is mainly used for heat dissipation. For some complex structural parts, the inner cavity is formed by a core in order to reduce weight, and the main purpose is to reduce weight.

People are eager to obtain a method for splicing an annular ceramic core containing blades with excellent technical effects.

Summary of the invention

The object of the present invention is to provide a method for splicing an annular ceramic core including blades.

The annular ceramic core of the blade is a medium-to-large-sized casting, which is composed of an outer flow channel, an inner flow channel, and blades. The outer flow channel and the inner flow channel are connected by hundreds of blades evenly distributed. The width between the inner and outer flow channels is relatively small. The blades and the flow channel are precision cast without allowance, and other parts are cast with allowance. Due to the complex structure of the inner cavity, the inner cavity cannot be formed by the shell, which leads to the process scheme of forming the inner cavity by using a ceramic core. Due to the large diameter size, the diameter size is above 400mm, the dimensional accuracy requirements are high, and the overall core manufacturing is difficult. In order to meet the requirements of the inner cavity blade structure and dimensional accuracy, it is necessary to strengthen the dimensional accuracy of the core. The flow channel surface and blade shape formed by the ceramic core are the core dimensions of the casting, which are directly involved in the flow of the working airflow of the engine.

The specific steps of the splicing method of the annular ceramic core including blades are as follows:

Step 1: divide the annular integral core into multiple split cores of the same size; decompose the entire core into multiple equal parts, each split core is of the same size, and after decomposing the annular integral core, multiple parting surfaces are formed on the split cores. The edge position that passes through the air inlet edge and the exhaust edge blade shape is selected as the parting line, and the parting line is distributed in sections and passes through the hollow blade shape position. The parting line is used to divide the annular integral core into the split cores.

Step 2: After the parting line separates the core, a contact parting surface, a free parting surface and an auxiliary locking structure are formed on the side of the core; during the wax mold pressing process, the high-pressure and high-temperature wax mold impacts the core, which will cause the split cores to change from the original free fitting state to a stress state of mutual contact and extrusion collision. The core is subjected to a small amount of displacement and deflection, which can easily lead to defects such as core breakage and partial meat shortage. In order to solve the problem of mutual contact, extrusion and collision between the split cores after being subjected to force, three main surfaces are set between the split cores: contact surface, free surface and auxiliary locking structure.

The contact parting surface is located at the thick part of the lower part of the air inlet side of the blade structure. The thickness of the thick part where the contact parting surface is located is 20mm-40mm. Since the core at this position is thick and has a strong load-bearing capacity, the reserved process design gap as a contact surface is slightly smaller.

The free parting surface is located at the weak position of the upper exhaust side of the blade structure, and the thickness of the weak position where the free parting surface is located is 3mm-8mm; the thickness of this position is relatively small, and a larger gap is designed between adjacent free parting surfaces to protect the core at the weak position, avoid the split cores from squeezing each other during the wax mold pressing process and cause the core to break, and reduce the scrap caused by squeezing each other between the split cores.

The auxiliary locking structure includes a boss and a groove, and the boss and the groove are respectively arranged at both ends of the contact parting surface and the free parting surface; the length of the boss and the groove is 8-15mm, the upper and lower parts of one end are both designed as bosses, and the upper and lower parts of the other end are both designed as grooves. Adjacent split cores cooperate with each other through the bosses and grooves to form a matching relationship, which is used for auxiliary positioning of the core during the wax mold pressing process.

After the split core design is completed, the split core mold is used to make the blank, and the split core blank is sintered, trimmed and other processes are performed to complete the manufacture of the split core.

Step 3: Positioning and installing the split core to form an integral core;

Install the split cores one by one into the core positioning tooling, and independently position each split core in the core positioning tooling. After all the split cores are positioned and installed, an integral core is formed in the tooling. Compress the split cores to form a complete core for subsequent wax model pressing.

Preferably, in step three, the positioning of the split core in the core splicing tooling includes three directions: left and right, up and down, and front and back. Two positioning points for limiting the front and back position of the core along the axial direction are respectively arranged on the upper and lower surfaces of the basin side of the split core, and a transverse positioning surface is arranged at the semicircular notch position of the split core for positioning in the left and right directions; a vertical positioning surface for limiting the vertical position is arranged on the bottom surface of the split core to ensure the position of the core in the up and down directions.

Preferably, the gap between adjacent contact parting surfaces is greater than the gap between adjacent free parting surfaces. The gap between adjacent contact parting surfaces ranges from 0.05 mm to 0.15 mm, and the gap between adjacent free parting surfaces ranges from 0.2 to 0.4 mm.

The method for splicing an annular ceramic core containing blades reasonably splits the annular ceramic core. First, the number of splits is determined, and the entire structure is split into evenly distributed split structures, each with a length of more than 150 mm, including dozens of split cores. A larger number of splits will lead to an increase in the splicing gap, and a smaller number of splits will increase the difficulty of manufacturing a single split core itself. The second is the position of the parting surface. The parting surface has two functions. One is to ensure the minimum dimensional loss and improve the dimensional accuracy of the core, and the other is to accurately position the cores. Finally, there is the positioning and gap between the split cores. The positioning ensures the relative relationship between each split core, and the gap ensures that a buffer is formed during the manufacturing process, reducing core breakage and affecting the quality of the final product. Each split ceramic core is set with an independent positioning reference, and multi-point positioning is adopted, including 4 front and rear positioning references and 2 upper and lower bottom positioning references.

The method for splicing an annular ceramic core containing blades adopts a technical solution of first splitting and then splicing. First, the ceramic core of the blade is evenly divided into several equal split cores, and the parting line position of the core is the air intake edge and the exhaust edge of the blade. The split core selects 4 positions on the basin side and 2 positions on the bottom for positioning on the splicing tooling. The thick part of the air intake edge of the core is the contact surface between the split cores, and the exhaust edge part forms a free surface. The gap between the contact surfaces of the split cores is small, and the gap between the free surfaces is controlled to be larger than the gap between the contact surfaces; auxiliary locking structures are set at the top and bottom of the contact surface and the free surface for auxiliary coordination of the parting surface; after the manufacture of the split ceramic core is completed, the split core is fixed on the splicing tooling respectively by using 4 positioning points and 2 positioning surfaces to finally form an integral core object.

The method for splicing an annular ceramic core including blades has the following advantages:

First, with the development of engine technology, the demand for large and complex casing castings has increased, and the number of annular ceramic core structure products has increased piece by piece. The annular ceramic core splicing method containing blades can be further extended to the production of similar structural casing products, with a wide range of applications.

Second, improve product qualification rate and production efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

FIG1 is a schematic diagram of the contact parting surface and the vertical positioning surface;

Fig. 2 is a schematic diagram of a free parting surface and a positioning point;

Fig. 3 is a cross-sectional view at A-A in Fig. 2;

FIG. 4 is a schematic diagram of an integral core.

DETAILED DESCRIPTION

Example 1

The specific steps of the splicing method of the annular ceramic core including blades are as follows:

Step 1: divide the annular integral core into multiple split cores of the same size; decompose the entire core into multiple equal parts, each split core is of the same size, and after decomposing the annular integral core, multiple parting surfaces are formed on the split cores. The edge position that passes through the air inlet edge and the exhaust edge blade shape is selected as the parting line, and the parting line is distributed in sections and passes through the hollow blade shape position. The parting line is used to divide the annular integral core into the split cores.

Step 2: After the parting line separates the core, a contact parting surface 1, a free parting surface 2 and an auxiliary locking structure 6 are formed on the side of the core; during the wax mold pressing process, the high-pressure and high-temperature wax mold impacts the core, which will cause the split cores to change from the original free fitting state to a stress state of mutual contact and extrusion collision. The core is stressed to produce a small amount of displacement and deflection, which can easily lead to defects such as core breakage and partial meat shortage. In order to solve the problem of mutual contact, extrusion and collision between the split cores after being stressed, three main molding surfaces are set between the split cores: contact surface, free surface and auxiliary locking structure.

The contact parting surface 1 is located at the thick part of the lower part of the air inlet side of the blade structure. The thickness of the thick part where the contact parting surface 1 is located is 20mm-40mm. Since the core at this position is thick and has a strong load-bearing capacity, the reserved process design gap as a contact surface is slightly smaller.

The free parting surface 2 is located at the weak position of the upper exhaust side of the blade structure, and the thickness of the weak position where the free parting surface 2 is located is 3mm-8mm; the thickness of this position is relatively small, and a larger gap is designed between adjacent free parting surfaces 2 to protect the core at the weak position, avoid the split cores from squeezing each other during the wax mold pressing process to cause the core to break, and reduce the scrap caused by squeezing each other between the split cores.

The auxiliary locking structure 6 includes a boss and a groove, and the boss and the groove are respectively arranged at both ends of the contact parting surface 1 and the free parting surface 2; the length of the boss and the groove is 8-15mm, the upper and lower parts of one end are designed as bosses, and the upper and lower parts of the other end are designed as grooves. The adjacent split cores cooperate with each other through the protrusions and grooves to form a matching relationship, which is used for auxiliary positioning of the core during the wax mold pressing process.

After the split core design is completed, the split core mold is used to make the blank, and the split core blank is sintered, trimmed and other processes are performed to complete the manufacture of the split core.

Step 3: Positioning and installing the split core to form an integral core;

Install the split cores one by one into the core positioning tooling, and independently position each split core in the core positioning tooling. After all the split cores are positioned and installed, an integral core is formed in the tooling. Compress the split cores to form a complete core for subsequent wax model pressing.

Preferably, in step three, the positioning of the split core in the core splicing tooling includes three directions: left and right, up and down, and front and back. Two positioning points 3 for limiting the front and back positions of the core along the axial direction are respectively arranged on the upper and lower surfaces of the basin side of the split core, and a transverse positioning surface 4 is arranged at the semicircular notch position of the split core for positioning in the left and right directions; a vertical positioning surface 5 for limiting the vertical position is arranged on the bottom surface of the split core to ensure the position of the core in the up and down directions.

Preferably, the gap between adjacent contact parting surfaces 1 is greater than the gap between adjacent free parting surfaces 2. The gap between adjacent contact parting surfaces 1 is in the range of 0.05 mm to 0.15 mm, and the gap between adjacent free parting surfaces 2 is in the range of 0.2 mm to 0.4 mm.

Claims (2)

1. A splicing method of annular ceramic cores containing blades is characterized in that: the splicing method of the annular ceramic core containing the blade comprises the following specific steps:

Step one, uniformly dividing the annular integral core into a plurality of split cores with the same size; selecting edge positions penetrating through the blade profiles of the air inlet side and the air outlet side to be determined as parting lines, wherein the parting lines are distributed in a sectional mode, and penetrate through the hollow blade profile positions;

step two, after the parting line splits the mold core, a contact parting surface (1), a free parting surface (2) and an auxiliary locking structure (6) are formed on the side surface of the mold core; the contact parting surface (1) is positioned at a thick part at the lower part of the air inlet side of the blade-shaped structure, the thickness of the thick part at which the contact parting surface (1) is positioned is 20mm-40mm, the free parting surface (2) is positioned at a weak part at the upper part of the air outlet side of the blade-shaped structure, the thickness of the weak part at which the free parting surface (2) is positioned is 3mm-8mm, the auxiliary locking structure (6) comprises a boss and a groove, and the boss and the groove are respectively arranged at two ends of the contact parting surface (1) and the free parting surface (2);

The gap range of the adjacent contact parting surfaces (1) is 0.05mm-0.15mm; the clearance range of the adjacent free parting surfaces (2) is 0.2-0.4mm;

Step three, positioning and installing the split core to form an integral core;

and installing the split cores into the core positioning tool one by one, independently positioning each split core in the core positioning tool, and forming an integral core in the tool after positioning and installing all the split cores.

2. The method for splicing a ceramic core in a ring shape comprising a blade according to claim 1, wherein: in the third step, 2 positioning points (3) for limiting the front and rear positions of the split core along the axial direction are respectively arranged on the upper surface and the lower surface of the basin side of the split core, a transverse positioning surface (4) is arranged at the semicircular opening position of the split core, and a vertical positioning surface (5) is arranged on the bottom surface of the split core.