Integral forming die and method for ceramic matrix composite adjusting sheet of aero-engine

Abstract

The invention discloses an integral forming die and method for an aero-engine ceramic matrix composite adjusting sheet, belongs to the technical field of forming of engine ceramic matrix composite adjusting sheets, and solves the problems that an existing forming processing method is high in preparation cost and insufficient in integral strength. The forming mold comprises a graphite mold and a preform tool, the prefabricated body tool is used for forming a box-type prefabricated body, and the formed box-type prefabricated body is put into a graphite mold to be subjected to chemical vapor deposition. According to the preparation method, the box-shaped prefabricated body is formed by utilizing the prefabricated body tool, and the formed box-shaped prefabricated body is placed in the graphite mold for chemical vapor deposition, so that the integrated preparation of the engine adjusting sheet is realized; the prefabricated body is integrally formed in a two-dimensional lamination manner, so that the preparation period of the prefabricated body is shortened; in the subsequent ceramic matrix composite material preparation process, part assembling and riveting do not need to be carried out on the product, the obtained ceramic matrix composite material adjusting piece is high in overall connectivity, and the situation that the riveting position is loosened in the long-term use process is avoided.

Description

Technical Field

[0001] This invention relates to the field of molding technology for ceramic matrix composite adjustment plates for engines, and particularly to an integral molding mold and method for ceramic matrix composite adjustment plates for aero-engines. Background Technology

[0002] With the continuous advancement of aero-engine technology, the working conditions of its related components are becoming increasingly demanding. Aero-engine exhaust nozzle trimmers, which regulate the exhaust plume, withstand temperatures exceeding 1000℃ during engine operation. Therefore, the materials used must possess high temperature and erosion resistance, as well as good bending and tensile strength. Traditional metal materials can no longer meet these performance requirements. Continuous fiber-reinforced ceramic matrix composites (CMCs) offer advantages such as high strength, high temperature resistance, corrosion resistance, and relatively low weight compared to metal materials, and are increasingly being applied in the aero-engine field. Therefore, using CMCs to fabricate aero-engine exhaust nozzle trimmers has become an important and urgently needed direction. Irregularly shaped fiber-reinforced CMCs are generally preformed using weaving technology.

[0003] Currently, the ceramic matrix composite components used in aero engines have relatively simple structures. For complex structural components, prefabricated components are mostly prepared using a split molding process or integrally molded using a weaving method. The split molding process requires assembly and riveting of the product, and assembly molding suffers from large gaps between parts, insufficient overall strength, and a short service life. The weaving method requires weaving equipment, which has high requirements for the equipment, and the preparation cycle is long and the cost is high. Compared with the weaving method, the two-dimensional laminated molding method has a significantly shorter preparation cycle and a significantly lower manufacturing cost. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an integral molding mold and method for ceramic matrix composite adjustment plates for aero-engines, which solves the problems of high manufacturing costs and insufficient overall strength of existing molding and processing methods.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A mold for integral molding of a ceramic matrix composite adjustment plate for an aero-engine includes a graphite mold and a preform tooling; the preform tooling is used to form a box-shaped preform, and after the box-shaped preform is formed, it is placed in the graphite mold for chemical vapor deposition. The prefabrication fixture includes several box-shaped fixtures and a base plate. Each box-shaped fixture is used to form a box-shaped prefabricated body. After the box-shaped prefabricated bodies are formed, they are connected to the base plate by fixing them with the box-shaped fixtures. The graphite mold includes an outer mold assembly and an inner mold assembly, with the number of inner mold assemblies equal to that of the box-shaped tooling; during chemical vapor deposition, the box-shaped preform is clamped between the inner mold assembly and the outer mold assembly.

[0006] In this solution, a specialized prefabrication tooling is used to form a box-shaped prefabrication. After forming, it is placed in a graphite mold for chemical vapor deposition. Compared with braiding, this shortens the prefabrication preparation cycle. It also enables the integrated preparation of engine adjustment plates, eliminating the need for subsequent parts assembly and riveting, resulting in high overall product strength.

[0007] Furthermore, the inner mold assembly includes two inner molds, with a composite gasket sandwiched between the two inner molds; The outer mold assembly includes a lower mold, an upper mold, side molds, and positioning pins. The lower mold and the upper mold are interlocked and connected by bolts. Side molds are provided at the front ends of the lower mold and the upper mold. The bottom of the positioning pin passes through the upper mold and is embedded in the groove of the inner mold.

[0008] In this design, the inner mold assembly is designed as two separate inner molds, which makes it easy to insert them into the box-shaped preform. The design of the positioning pin can restrict the position of the inner mold in the horizontal direction, which is equivalent to restricting the position of the box-shaped preform, resulting in a preform with high dimensional accuracy.

[0009] Furthermore, the precast fixture also includes a metal limiting ring, which is formed by connecting four L-shaped limiting rods end to end with fastening bolts; the metal limiting ring is fitted around several box-shaped precast bodies on the base plate.

[0010] In this solution, when sewing the precast box-shaped bodies, several precast box-shaped bodies can be fixed by metal limiting rings to prevent them from loosening or shifting during sewing.

[0011] Furthermore, the base plate is provided with several mounting slots, and the box-shaped tooling is installed in the mounting slots one by one; The bottom of the box-shaped tooling has a strip-shaped sewing hole; The side of the box-shaped tooling has stepped grooves.

[0012] In this scheme, the design of the stepped groove allows the carbon cloth used to prepare the box-shaped preform to be cut according to the position of the stepped groove, ensuring that multiple box-shaped preforms are prepared with the same height.

[0013] Secondly, based on the integral molding mold for an aero-engine ceramic matrix composite adjustment plate provided in the first aspect, the present invention provides a method for integral molding of an aero-engine ceramic matrix composite adjustment plate, comprising the following steps: S1: Use box-shaped tooling to form a box-shaped prefabricated body; S2: Fix the box-shaped tooling with the box-shaped prefabricated body to the bottom plate; S3: Lay several layers of silicon carbide cloth on the box-shaped precast body and sew the laid silicon carbide cloth to the box-shaped precast body together; S4: After sewing, place the prefabricated box into the lower mold and remove the bottom plate and box tooling; S5: Use carbon fiber to sew the side walls of two adjacent box-shaped prefabricated bodies; S6: Embed the inner mold components one by one into the box-shaped precast body, and install the upper mold and side mold; S7: The graphite mold and box-shaped preform are placed as a whole into a chemical vapor deposition equipment for pyrolytic carbon interface layer deposition and SiC matrix deposition.

[0014] Furthermore, S1 includes the following steps: S101: Add a layer of carbon cloth to the end of the box-shaped tooling; S102: Add 5-6 more layers of silicon carbide cloth on top of the carbon cloth; S103: Cut off excess carbon fiber according to the position of the stepped groove on the side wall of the box-shaped tooling; S104: Prepare box-shaped preforms on other box-shaped tooling using the same method.

[0015] Furthermore, S2 includes the following steps: S201: Fix the end of the box-shaped tooling that is not used to form the box-shaped prefabricated body into the mounting groove of the bottom plate; S202: Fill the gap formed at the vertical R-angle of adjacent box-shaped prefabricated bodies with fiber bundles; S203: Fill the gap formed at the horizontal R-angle of adjacent box-shaped prefabricated bodies with fiber bundles.

[0016] Furthermore, S3 includes the following steps: S301: Lay 7-8 layers of third-generation silicon carbide cloth on the box-shaped precast body; S302: Place four L-shaped limiting rods around the box-shaped precast body and connect them end to end with fastening bolts to form a metal limiting ring; S303: Using carbon fiber, sew the bottom of the box-shaped prefabricated body together with the silicon carbide cloth laid in S301, according to the sewing holes at the bottom of the box-shaped tooling.

[0017] Furthermore, S4 includes the following steps: S401: Remove the metal retaining ring; S402: Place the box-shaped preform with the side sewn with silicon carbide cloth facing down in the lower mold; S403: Remove the base plate; S404: Remove the box-shaped fixtures from the box-shaped prefabrication body one by one.

[0018] Furthermore, S6 includes the following steps: S601: A set of inner mold components is embedded inside each box-shaped precast body. When embedding, two inner molds are first inserted into the corresponding box-shaped precast body, and then a composite material gasket is inserted between the two inner molds. S602: Install the upper mold on the lower mold, and install the side mold on the front end of the lower mold and the upper mold. After installation, fix it with bolts.

[0019] The beneficial effects of this invention are: The molding method for the integral molding mold of the aero-engine ceramic matrix composite adjustment plate provided by this invention uses a specific preform tooling to form a box-shaped preform and adopts a two-dimensional lamination molding method of SiC fiber cloth to achieve integrated molding of the complex structure of the aero-engine adjustment plate preform. This method uses a two-dimensional lamination method to integrally mold the preform, which shortens the preform preparation cycle compared to weaving molding; compared to split molding, after the preform is formed, there is no need for parts assembly and riveting in the subsequent ceramic matrix composite material preparation process, resulting in a ceramic matrix composite adjustment plate with strong overall connectivity and avoiding loosening of riveted positions during long-term use. The box-shaped preform formed using the preform tooling has high dimensional accuracy, and the graphite mold has a certain correction function in the subsequent chemical vapor deposition process to ensure the external standard of the obtained product; in addition, the preform tooling and graphite mold are reusable, reducing manufacturing costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the outer mold assembly in this invention; Figure 2 This is a schematic diagram of the internal mold assembly in this invention; Figure 3 This is a schematic diagram of the structure in which the inner mold component is embedded in the box-shaped prefabricated body in this invention; Figure 4 This is an exploded view of a single internal mold component in this invention; Figure 5 This is a schematic diagram of the prefabricated tooling in this invention; Figure 6 This is a schematic diagram of the prefabricated tooling for removing the metal limiting ring in this invention; Figure 7 This is a schematic diagram of the positioning pin in this invention; Figure 8 This is a schematic diagram of the structure of the box-shaped preform formed by the box-shaped tooling in this invention; Figure 9 This is a schematic diagram of the structure of inserting a box-shaped tooling with a box-shaped prefabricated body into the mounting slot in this invention; Figure 10 This is a schematic diagram of the structure in this invention where all the box-shaped tooling is fixed on the base plate; Figure 11 This is a schematic diagram of the structure of laying silicon carbide cloth on the box-shaped preform in this invention; Figure 12 This is a schematic diagram of the structure of installing a metal limiting ring around the box-shaped prefabricated body in this invention; Figure 13 This is a schematic diagram of the structure of sewing the box-shaped prefabricated body and the laid silicon carbide cloth in this invention; Figure 14 This is a schematic diagram of the structure in this invention in which the side of the box-shaped prefabricated body sewn with silicon carbide cloth is placed downwards in the lower mold; Figure 15 This is a schematic diagram of the box-shaped tooling used to remove the box-shaped prefabricated bodies one by one in this invention.

[0021] Figure label: 1. Outer mold assembly; 11. Lower mold; 12. Upper mold; 13. Side mold; 14. Positioning pin; 2. Inner mold assembly; 21. Inner mold; 22. Composite material gasket; 3. Box-shaped tooling; 31. Sewing hole; 4. Metal limiting ring; 41. L-shaped limiting rod; 42. Fastening bolt; 5. Base plate; 51. Mounting groove; 6. Box-shaped precast body; Detailed Implementation The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Specific embodiments of the present invention are described below to facilitate understanding by those skilled in the art. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various modifications are obvious as long as they fall within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0022] Example 1 like Figures 1-6 As shown, this embodiment provides an integral molding mold for aero-engine ceramic matrix composite adjustment plates, which solves the problems of high preparation cost and insufficient overall strength of existing molding and processing methods; it specifically includes: a graphite mold and a preform tooling; the preform tooling is used to form a box-shaped preform 6, and after the box-shaped preform 6 is formed, it is placed in the graphite mold for chemical vapor deposition.

[0023] like Figure 5 and Figure 6As shown, the prefabrication fixture includes several box-shaped fixtures 3, a base plate 5, and metal limiting rings 4. Each box-shaped fixture 3 forms a box-shaped prefabricated body 6. After forming, the box-shaped prefabricated bodies 6 are connected and fixed to the base plate 5 by the box-shaped fixtures 3. The base plate 5 has several mounting slots 51. When installing the box-shaped fixtures 3 on the base plate 5, each box-shaped fixture 3 is installed in a corresponding mounting slot 51. The bottom of the box-shaped fixture 3 has a strip-shaped sewing hole 31. The side of the box-shaped fixture 3 has stepped grooves. The design of the stepped grooves allows the carbon fiber used to prepare the box-shaped prefabricated bodies 6 to be cut according to the position of the stepped grooves, ensuring that the height of the multiple box-shaped prefabricated bodies 6 meets the standard. The metal limiting ring 4 is formed by connecting four L-shaped limiting rods 41 end to end with fastening bolts 42. When the box-shaped prefabricated body 6 is sewn later, the metal limiting ring 4 is sleeved around several box-shaped prefabricated bodies 6 on the base plate 5, which can fix several box-shaped prefabricated bodies 6 and prevent the box-shaped prefabricated bodies 6 from loosening or shifting during sewing.

[0024] like Figure 1 and Figure 2 As shown, the graphite mold includes an outer mold assembly 1 and an inner mold assembly 2, with the same number of inner mold assemblies 2 as the box-shaped tooling 3; during chemical vapor deposition, the box-shaped preform 6 is clamped between the inner mold assembly 2 and the outer mold assembly 1.

[0025] like Figure 4 As shown, the inner mold assembly 2 includes two inner molds 21, with a composite material gasket 22 sandwiched between them. This split design of the two inner molds 21 facilitates their insertion into the box-shaped precast body 6. Figure 1 As shown, the outer mold assembly 1 includes a lower mold 11, an upper mold 12, a side mold 13, and a positioning pin 14. The lower mold 11 and the upper mold 12 are interlocked and connected by bolts. The front ends of the lower mold 11 and the upper mold 12 are provided with side molds 13. The inner mold assembly 2 is distributed within the cavity formed by the lower mold 11, the upper mold 12, and the side molds 13, as shown. Figure 3 As shown. The bottom of the positioning pin 14 passes through the upper mold 12 and is embedded in the groove of the inner mold 21, as shown. Figure 7 As shown, the positioning pin 14 can restrict the position of the inner mold 21 in the horizontal direction, which is equivalent to restricting the position of the box-shaped preform 6, resulting in a high dimensional accuracy of the preform.

[0026] The number and layout of the inner mold assembly 2 are determined based on the actual shape of the engine adjustment plate. Each rectangular frame composed of the intersecting horizontal and vertical ribs inside the engine adjustment plate corresponds to each box-shaped preform 6 in the molding process. Therefore, the number of inner mold assemblies 2 also corresponds to the rectangular frames inside the engine adjustment plate. In the actual manufacturing process, the specific number of inner mold assemblies 2 can be determined according to the designed shape of the engine adjustment plate.

[0027] The graphite molds are all perforated with ventilation holes, with a hole spacing of 6~10mm and a hole diameter of 3~5mm, to facilitate subsequent chemical vapor deposition processes.

[0028] Example 2 This embodiment, based on the integral molding mold for an aero-engine ceramic matrix composite adjustment plate provided in Embodiment 1, provides a method for integral molding of an aero-engine ceramic matrix composite adjustment plate, including the following steps: S1: Use box-shaped tooling 3 to form the box-shaped prefabricated body 6; specifically including: S101: Turn a layer of 1k carbon cloth, approximately 0.17mm thick, onto the end of the box-shaped tooling 3; S102: Add 5-6 layers of third-generation silicon carbide cloth on top of the carbon cloth, with a thickness of about 1.5mm; S103: Cut off excess carbon fiber according to the position of the stepped groove on the side wall of the box-shaped tooling, such as... Figure 8 As shown.

[0029] S104: Prepare box-shaped preforms 6 on other box-shaped tooling 3 using the same method.

[0030] S2: Fix the box-shaped fixture 3 with the box-shaped prefabricated body 6 onto the base plate 5; specifically including: S201: Fix the end of the box-shaped tooling 3 that is not used to form the precast box-shaped body 6 into the mounting groove 51 of the base plate 5, such as Figure 9 As shown; S202: Fill the gap formed at the vertical R-angle of the adjacent box-shaped prefabricated body 6 with fiber bundles, and fill the fiber bundles once for each box-shaped prefabricated body 6 inserted. S203: Fill the gaps formed at the horizontal R-angle of adjacent box-shaped prefabricated bodies 6 with fiber bundles, such as... Figure 10 As shown.

[0031] S3: Lay several layers of silicon carbide cloth on the box-shaped prefabricated body 6, and sew the laid silicon carbide cloth to the box-shaped prefabricated body 6 together; specifically including: S301: As Figure 11 As shown, 7-8 layers of third-generation silicon carbide cloth with a thickness of about 2mm are laid on the box-shaped prefabricated body 6; S302: Place four L-shaped limiting rods 41 around the perimeter of the box-shaped precast body 6, and connect them end to end with fastening bolts 42 to form a metal limiting ring 4, such as... Figure 12 As shown; S303: Erect the entire assembly consisting of the base plate 5, the metal limiting ring 4, and the box-shaped fixture 3. Following the sewing holes 31 at the bottom of the box-shaped fixture 3, use 3K carbon fiber to sew the bottom of the box-shaped prefabricated body 6 to the silicon carbide cloth laid in S301. The sewing density is 3mm × 3mm. Figure 13As shown; S4: After sewing, place the prefabricated box 6 into the lower mold 11, and remove the base plate 5 and the box fixture 3; specifically including: S401: Remove the metal limiting ring 4; S402: Place the box-shaped preform 6 with the side sewn with silicon carbide cloth facing down inside the lower mold 11, such as... Figure 14 As shown; S403: Remove base plate 5; S404: And remove the box-shaped fixtures 3 one by one from the box-shaped prefabricated body 6, such as Figure 15 As shown; S5: Use 3K carbon fiber to sew the side walls of two adjacent box-shaped prefabricated bodies 6.

[0032] S6: Embed the inner mold components 2 one by one into the box-shaped precast body 6, and install the upper mold 12 and side mold 13; specifically including: S601: A set of inner mold components 2 are embedded inside each box-shaped precast body 6. During embedding, two inner molds 21 are first inserted into the corresponding box-shaped precast body 6, and then a composite material spacer 22 is inserted between the two inner molds 21. Figure 3 As shown; S602: Install the upper mold 12 on the lower mold 11, and install the side mold 13 on the front end of the lower mold 11 and the upper mold 12. After installation, fix them with bolts. Figure 1 As shown.

[0033] S7: The graphite mold and the box-shaped preform 6 are placed as a whole into the chemical vapor deposition equipment for pyrolytic carbon interface layer deposition and SiC matrix deposition.

[0034] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention and should be understood as not limiting the scope of protection of the invention to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed herein without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of the invention.

Claims

1. A mold for integral molding of a ceramic matrix composite adjustment plate for an aero-engine, characterized in that: It includes a graphite mold and a preform tooling; the preform tooling is used to form a box-shaped preform (6), and the box-shaped preform (6) is placed in the graphite mold for chemical vapor deposition after being formed; The prefabricated fixture includes several box-shaped fixtures (3) and a base plate (5). Each box-shaped fixture (3) forms a box-shaped prefabricated body (6). After the box-shaped prefabricated bodies (6) are formed, they are connected by fixing them to the base plate (5) through the box-shaped fixtures (3). The graphite mold includes an outer mold assembly (1) and an inner mold assembly (2), the number of which is equal to the number of the box-shaped tooling (3); during chemical vapor deposition, the box-shaped preform (6) is held between the inner mold assembly (2) and the outer mold assembly (1).

2. The integral molding die for the aero-engine ceramic matrix composite material adjustment plate according to claim 1, characterized in that: The inner mold assembly (2) includes two inner molds (21), with a composite gasket (22) sandwiched between the two inner molds (21). The outer mold assembly (1) includes a lower mold (11), an upper mold (12), a side mold (13), and a positioning pin (14). The lower mold (11) and the upper mold (12) are fastened together and connected by bolts. The front ends of the lower mold (11) and the upper mold (12) are provided with side molds (13). The bottom of the positioning pin (14) passes through the upper mold (12) and is embedded in the groove of the inner mold (21).

3. The integral molding die for the aero-engine ceramic matrix composite material adjustment plate according to claim 1, characterized in that: The prefabricated fixture also includes a metal limiting ring (4), which is formed by connecting four L-shaped limiting rods (41) end to end with fastening bolts (42); the metal limiting ring is sleeved around several box-shaped prefabricated bodies (6) on the base plate (5).

4. The integral molding mold for the aero-engine ceramic matrix composite material adjustment plate according to claim 3, characterized in that: The base plate (5) is provided with several mounting slots (51), and the box-shaped tooling (3) is installed in the mounting slots (51) one by one; The bottom of the box-shaped tooling (3) is provided with a strip-shaped sewing hole (31). The side of the box-shaped tooling (3) is provided with a stepped groove.

5. A molding method for an integral molding die for an aero-engine ceramic matrix composite adjustment plate according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1: Use box-shaped tooling (3) to form a box-shaped preform (6); S2: Fix the box-shaped fixture (3) with the box-shaped prefabricated body (6) onto the base plate (5); S3: Lay several layers of silicon carbide cloth on the box-shaped precast body (6) and sew the laid silicon carbide cloth together with the box-shaped precast body (6); S4: After sewing, place the box-shaped prefabricated body (6) into the lower mold (11) and remove the bottom plate (5) and box-shaped tooling (3). S5: Use carbon fiber to sew the sidewalls of two adjacent box-shaped prefabricated bodies (6); S6: Embed the inner mold components (2) one by one into the box-shaped precast body (6), and install the upper mold (12) and the side mold (13). S7: Place the graphite mold and box-shaped preform (6) as a whole into the chemical vapor deposition equipment for pyrolytic carbon interface layer deposition and SiC matrix deposition.

6. The molding method of the integral molding mold for the aero-engine ceramic matrix composite adjustment plate according to claim 5, characterized in that, S1 includes the following steps: S101: Turn a layer of carbon cloth over the end of the box-shaped tooling (3); S102: Add 5-6 more layers of silicon carbide cloth on top of the carbon cloth; S103: Cut off excess carbon cloth according to the position of the stepped groove on the side wall of the box-type tooling (3); S104: Prepare box-shaped preforms (6) on other box-shaped tooling (3) using the same method.

7. The molding method of the integral molding mold for the aero-engine ceramic matrix composite material adjustment plate according to claim 6, characterized in that, S2 includes the following steps: S201: Fix the end of the box-shaped tooling (3) that is not used to form the box-shaped prefabricated body (6) into the mounting groove of the bottom plate (5); S202: Fill the gap formed at the vertical R-angle of the adjacent box-shaped prefabricated body (6) with fiber bundles; S203: Fill the gap formed at the R-angle in the horizontal direction of the adjacent box-shaped prefabricated body (6) with fiber bundles.

8. The molding method of the integral molding mold for the aero-engine ceramic matrix composite adjustment plate according to claim 7, characterized in that, S3 includes the following steps: S301: Lay 7-8 layers of third-generation silicon carbide cloth on the box-shaped precast body (6); S302: Place four L-shaped limiting rods (41) around the box-shaped precast body (6) and connect them end to end with fastening bolts (42) to form a metal limiting ring (4). S303: According to the sewing hole (31) at the bottom of the box-shaped tooling (3), use carbon fiber to sew the bottom of the box-shaped prefabricated body (6) and the silicon carbide cloth laid in S301 together.

9. The molding method of the integral molding mold for the aero-engine ceramic matrix composite adjustment plate according to claim 8, characterized in that, S4 includes the following steps: S401: Remove the metal limiting ring (4); S402: Place the box-shaped preform (6) with the side sewn with silicon carbide cloth facing down into the lower mold (11); S403: Remove the base plate (5); S404: Take out the box-shaped fixtures (3) one by one from the box-shaped prefabricated body (6).

10. The molding method of the integral molding mold for the aero-engine ceramic matrix composite adjustment plate according to claim 9, characterized in that, S6 includes the following steps: S601: A set of inner mold components (2) are embedded inside each box-shaped prefabricated body (6). When embedding, two inner molds (21) are first inserted into the corresponding box-shaped prefabricated body (6), and then a composite material gasket (22) is inserted between the two inner molds (21). S602: Install the upper mold (12) on the lower mold (11), and install the side mold (13) on the front end of the lower mold (11) and the upper mold (12), and fix it with bolts after installation.

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