CN117921906A - Forming die applied to S-shaped variable cross-section structure air inlet channel and application method - Google Patents

Abstract

A forming die applied to an S-shaped variable cross-section structure air inlet channel and a use method thereof comprise a base, wherein a base groove is formed in the center of the base, a core die is fixedly arranged in the base groove in a vertical shape, a movable block die assembly is arranged at a die body of the core die, movable blocks of the movable block die assembly are assembled to the base groove and the core die in sequence, the upper section of the movable block die assembly is connected with a lip die, and a fixing plate is arranged at the tops of the core die and the movable block die assembly. The invention has the advantages of high precision, high safety and reliability, strong operability, block design of each movable block of the die, full die drawing analysis, simulation of the die assembly and demolding process in actual production and low risk. All parts of the invention are made of metal, are firm and durable, can be repeatedly used, and can be used for the production of batch products.

Description

Forming die applied to S-shaped variable cross-section structure air inlet channel and application method

Technical Field

The invention relates to the field of moulds in manufacturing industry, in particular to an S-shaped air inlet channel forming mould applied to aviation manufacturing technology.

Background

At present, the carbon fiber composite material is widely applied to the aerospace field due to the characteristics of light weight and high strength, and particularly applied to the field of aircrafts/unmanned aerial vehicles, so that the carbon fiber composite material has more excellent performance.

The S-shaped variable cross-section structure air inlet of the airplane/unmanned aerial vehicle can greatly improve air inlet efficiency and reduce radar reflected waves of the air inlet, so that stealth performance of the machine body is improved, and more scientific researchers select the S-shaped variable cross-section structure composite material air inlet in the machine body.

The S-shaped variable cross-section structure air inlet channel under the prior art generally adopts a resin-based carbon fiber composite material autoclave molding process, and in order to meet pneumatic requirements, the inner profile surface must ensure the air flow to circulate unimpeded, so that a male mold molding scheme is adopted, the male mold for molding the S-shaped variable cross-section structure air inlet channel is mainly divided into a metal combination mold, a soluble mold or a destructible mold, and the soluble mold and the destructible mold are relatively complex in manufacturing process, relatively high in cost and incapable of being repeatedly used, so that the metal combination mold is often selected for batch products. However, in the feedback of the field workers in the actual production, the S-shaped air inlet is of a variable cross-section structure, and the air inlet is of a closed angle structure, so that the demoulding speed of the metal combined mould is low, and errors can be caused possibly, and how to design the metal combined mould, so that smooth demoulding can be effectively, quickly and accurately ensured, and the problem of producing the air inlet of the S-shaped variable cross-section structure is always plagued.

Disclosure of Invention

In order to solve the problems that the demolding speed of a metal combined mold is low and errors possibly occur in accuracy in the prior art, the invention provides the forming mold applied to the S-shaped composite material air inlet channel with the variable cross-section structure, which has the advantages of high demolding accuracy, strong operability, high demolding speed and repeated use.

The invention relates to a forming die applied to an S-shaped variable cross-section structure air inlet channel and a use method thereof, and the specific structure and the method steps are as follows:

Be applied to forming die of S type variable cross section structure intake duct, including the base, its characterized in that:

The base is of a planar plate-shaped structure, the lower part of the base is provided with a foot pad, the center of the base is provided with a base groove, a core die is fixedly arranged in the base groove in a vertical shape, the lower end of the core die is connected with the base groove in a connecting mode of a locating pin and a fixing bolt, and the lower section of the core die is of a hollow structure;

the upper end of the movable block die assembly is level with the upper end of the core die;

the movable block die assembly is connected with a lip die by using a connecting mode of a locating pin and a fixing bolt at the upper section of the movable block die assembly for locating and fixing;

The top of mandrel and movable block mould subassembly be provided with the fixed plate, this fixed plate is flat plate structure, is provided with fixed connection hole on the face of fixed plate, this fixed connection hole matches with the connecting hole at the top of mandrel and movable block mould subassembly's top, namely, should the fixed plate be connected mandrel and movable block mould subassembly through locating pin and fixing bolt's connected mode and fix.

All parts are made of metal materials and are machined by a numerical control machine tool, positioning and fixing are carried out between all parts through positioning pins and bolts, and considering that the size of an air inlet channel is large, if all steel materials are selected, difficulties in transportation, transportation and disassembly are increased, so that the base and the core mold are used as main structures of the whole mold, the stability of the mold is kept, the fixing plate and the stripper plate are also made of steel materials due to small sizes, and the lip mold and all movable blocks forming the movable block mold assembly are made of aluminum materials, so that the overall weight of the mold is reduced.

The invention relates to a forming die applied to an S-shaped variable cross-section structure air inlet channel, which is characterized in that the movable block die assembly comprises a first movable block, a second movable block, a third movable block, a fourth movable block, a fifth movable block, a sixth movable block, a seventh movable block, an eighth movable block, a ninth movable block and a tenth movable block, wherein the first movable block, the ninth movable block and the tenth movable block are sequentially arranged at a hollow position of the lower section of a core die through positioning pins in a base groove of a base; the second movable block, the third movable block, the fourth movable block, the fifth movable block and the sixth movable block are respectively arranged at the middle section of the core mold through movable block positioning pins; and the seventh movable block and the eighth movable block are arranged at the two sides of the back of the upper section of the core mold, and the whole movable block mold assembly is connected with the base and the core mold through the preset shape positioning.

The forming die for the S-shaped variable cross-section structure air inlet channel is characterized in that grooves and connecting holes are formed in the machining of each movable block of the movable block die assembly, connecting holes are formed in corresponding positions of a base groove and a core die, and fixing bolts are used for fixing the movable blocks, the base groove and the core die.

The forming die for the S-shaped variable cross-section structure air inlet channel is characterized in that lifting rings are arranged at the four corners of the upper surface of the base, and fork truck grooves are formed in the foot pads arranged at the lower part of the base.

The design aim at here is that because bottom plate + movable block mould subassembly overall quality is heavier, so in order to make things convenient for transportation and the dismouting of mould, be provided with rings on the base, pad foot department fork truck groove. In addition, each movable block of the core mold, the lip mold and the movable block mold assembly can be respectively provided with a hanging ring according to requirements.

The forming die for the S-shaped variable cross-section structure air inlet channel is characterized in that a stripper plate is arranged on the upper surface of the base, the stripper plate is of a flat plate structure and is fixed on the base through a fixing bolt, the stripper plate is provided with two locating pins, the locating pins are matched with locating pin holes of a nine-number movable block and a ten-number movable block which are positioned at the lower part of a movable block die assembly, and the stripper plate carries out auxiliary stripping on the two movable blocks during stripping.

Besides the stripper plate provided with the locating pin, the stripper plate is also provided with a flat plate structure with a connecting hole and a top thread hole, and the stripper plate is matched with the connecting hole of the movable block, so that the movable block can move in the vertical direction, and the movable block can be used for assisting in demolding of the movable block in the vertical direction. In addition, a U-shaped stripper plate may be used if translational assistance is required.

The application method of the forming die applied to the S-shaped air inlet channel with the variable cross-section structure is based on the forming die applied to the S-shaped air inlet channel with the variable cross-section structure, and the specific steps are as follows:

1) Firstly, connecting and fixing a base and a core mold by using a locating pin and a fixing bolt, and taking the base and the core mold as a main body structure of a mold;

2) Then, assembling each movable block of the movable block die assembly one by one according to the assembling sequence of the tenth movable block, the ninth movable block, the eighth movable block, the seventh movable block, the first movable block, the second movable block, the third movable block, the fourth movable block, the fifth movable block and the sixth movable block;

3) The step 2) is specifically as follows: the first movable block, the ninth movable block and the tenth movable block are sequentially arranged at the hollow position of the lower section of the core mold through positioning pins in a base groove of the base; the second movable block, the third movable block, the fourth movable block, the fifth movable block and the sixth movable block are respectively arranged at the middle section of the core mold through movable block positioning pins; the seventh movable block and the eighth movable block are arranged at the two sides of the back of the upper section of the core mold;

4) The movable blocks in the step 2) are mutually fixed with the base groove and the core mold through the connecting holes by using fixing bolts, each movable block is immediately connected after being positioned and installed, and the movable blocks and the core mold are confirmed to form preset shape positioning;

5) After all the movable blocks are installed, connecting and fixing the top parts of the movable block die assembly and the core die by using a fixing plate (4);

6) The assembled mould is cleaned, and the mould release agent is coated, so that the forming and paving work of the S-shaped variable cross-section structure composite material air inlet channel can be carried out;

7) After the S-shaped air inlet main body structure is paved, the lips are paved, and after all the lips are paved, the lip die and the main body die are positioned and fixed by using positioning pins and bolts. Then pasting a vacuum bag on the air inlet channel according to the process file requirements, curing the air inlet channel by an autoclave and the like, and discharging and demolding after the air inlet channel is cured;

8) The stripping steps are as follows:

The method comprises the steps of firstly removing a lip die and a fixed plate at the top of the die, removing fixing bolts connected with all movable blocks, then removing all the movable blocks from a base and a core die by using a stripper plate, starting from the first movable block to the eighth movable block in the removing sequence, then connecting and fixing the ninth movable block and the tenth movable block by using the fixed plate again, vertically extracting an S-shaped air inlet channel together with the fixed plate, the ninth movable block and the tenth movable block from the base and the core die by using a truss, extracting the ninth movable block and the tenth movable block from the lower part of the air inlet channel by using the truss and the stripper plate, and finally realizing smooth demolding of the S-shaped air inlet channel, thereby obtaining the S-shaped air inlet channel with smooth and flat inner surface and S-shaped variable cross-section structure.

The invention relates to a forming die applied to an S-shaped variable cross-section structure air inlet channel and a use method thereof, which are characterized in that:

Because S type combined material intake duct is closed angle and variable cross-section structure, the loose piece of metal composite mould need take out respectively from the both sides of intake duct and just can realize smooth drawing of patterns, considers convenience and the security of operation simultaneously, and the mould adopts erect the form to place, and the lip up, with engine link down, the equipment and the dismantlement of mould are all operated according to vertical direction. Because the S-shaped composite material air inlet channel has more closed angle structures, a movable block needs to be arranged at each closed angle position, and meanwhile, in order to ensure that the movable block can be taken out smoothly, the movable block needs to translate in the air inlet channel until no interference exists in the vertical direction. The blocking design mode of the mould is that a movable block is arranged in a closed angle area, a movable block without a closed angle structure is arranged in the middle of the mould, the movable block without the closed angle structure in the middle is taken out during demoulding, then the movable block in the closed angle area is translated to an interference-free area, and then the movable block is taken out along the vertical direction. After the block design is finished, the translation and collision functions in CATIA software are utilized to fully draw out the die, so that each movable block can be smoothly demoulded according to the corresponding sequence.

The forming die applied to the S-shaped variable cross-section structure air inlet channel and the using method of the forming die have the following beneficial effects:

(1) The forming die applied to the S-shaped variable cross-section structure air inlet and the using method thereof enable the accuracy of the inner profile of the air inlet to be high: all parts of the die are processed by adopting a digital machine tool, and after the die is assembled, the die surface is subjected to omnibearing scanning detection by using a laser scanner, so that the requirements on product precision and design are met;

(2) The forming die applied to the S-shaped variable cross-section structure air inlet channel and the using method thereof have high safety and reliability: all parts of the die are mechanically connected, so that the safety is good and the reliability is high.

The forming die applied to the S-shaped air inlet channel with the variable cross-section structure and the using method thereof have strong operability, wherein the forming die is designed to divide each movable block of the die according to the detailed structure of the S-shaped air inlet channel, and is subjected to full pattern drawing analysis, so that the die assembling and demolding processes in actual production can be simulated, the risk is low, and the operability is strong;

(4) The forming die applied to the S-shaped variable cross-section structure air inlet channel and the using method thereof can be repeatedly used: all parts of the die are made of metal, are firm and durable, can be repeatedly used, and can be used for producing batch products.

Drawings

FIG. 1 is a front view of a specific structure of a molding die and a method of use for an S-shaped variable cross-section structure air intake duct according to the present invention;

FIG. 2 is a left side view of a specific structure of a molding die and a using method for an S-shaped variable cross-section structure air inlet channel;

FIG. 3 is a right side view of a specific structure of a forming die and a using method for an S-shaped variable cross-section structure air inlet channel;

FIG. 4 is a specific block diagram of a base and core mold of the invention for an S-shaped variable cross-section structure inlet duct forming mold and method of use;

FIG. 5 is a schematic drawing (1) of a mold for forming an S-shaped air inlet duct with a variable cross-section structure and a method for using the mold;

FIG. 6 is a schematic drawing (2) of a mold for forming an S-shaped air intake duct with a variable cross-section structure and a method of using the same according to the present invention;

In the figure: the novel lifting device comprises a base, a foot pad, a base groove, a lifting ring, a core mold, a fixed connecting hole, A3-lip mold, A4-fixing plate, A5-stripper plate, A5 a-locating pin, an A-movable block mold assembly, an A1-movable block, an A2-second movable block, an A3-third movable block, an A4-fourth movable block, an A5-fifth movable block, an A6-sixth movable block, an A7-seventh movable block, an A8-eighth movable block, an A9-ninth movable block and an A10-tenth movable block.

Detailed Description

The invention further describes a forming die applied to an S-shaped variable cross-section structure air inlet channel and technical means, creation characteristics, achievement purposes and effects achieved by using the forming die and the use method by combining the drawings and the embodiments.

Examples

As shown in fig. 1 to 6, a forming die for an air inlet channel with an S-type variable cross-section structure comprises a base 1, wherein the base is of a planar plate-shaped structure, a foot pad 1a is arranged at the lower part of the base, a base groove 1b is arranged at the central position of the base, a core die 2 is fixedly arranged in the base groove in a vertical shape, the lower end of the core die is connected with the base groove in a connecting mode of a positioning pin and a fixing bolt, and the lower section of the core die is of a hollow structure;

a movable block mold assembly A is arranged at the mold body of the core mold 2, each movable block of the movable block mold assembly is assembled to the base groove and the core mold in sequence, and the upper end of the movable block mold assembly is level with the upper end of the core mold;

The movable block mold assembly A is connected, positioned and fixed with a lip mold 3 by using a connecting mode of a positioning pin and a fixing bolt at the upper section position of the movable block mold assembly A;

The top of mandrel 2 and movable block mould subassembly A is provided with fixed plate 4, and this fixed plate is flat plate structure, is provided with fixed connection hole 2a on the face of fixed plate, and this fixed connection hole matches with the connecting hole at the top of mandrel and movable block mould subassembly A's top, and this fixed plate is connected mandrel and movable block mould subassembly through locating pin and fixing bolt's connected mode promptly.

The movable block die assembly A comprises a first movable block A1, a second movable block A2, a third movable block A3, a fourth movable block A4, a fifth movable block A5, a sixth movable block A6, a seventh movable block A7, a eighth movable block A8, a ninth movable block A9 and a tenth movable block A10, wherein the first movable block, the ninth movable block and the tenth movable block are sequentially arranged at the hollow position of the lower section of the core die 2 through positioning pins in a base groove 1b of the base 1; the second movable block, the third movable block, the fourth movable block, the fifth movable block and the sixth movable block are respectively arranged at the middle section of the core mold through movable block positioning pins; and the seventh movable block and the eighth movable block are arranged at the two sides of the back of the upper section of the core mold, and the whole movable block mold assembly is connected with the base and the core mold through the preset shape positioning.

The processing of each movable block of the movable block mould assembly A is provided with a groove and a connecting hole, and the corresponding positions of the base groove 1b and the core mould 2 are also provided with connecting holes, and the fixed bolts are used for fixing each movable block, the base groove and the core mould.

The base 1 is provided with hanging rings 1c at four corners of the upper surface of the base, and fork truck grooves are formed in the positions of foot pads 1a arranged at the lower part of the base.

The base 1 is provided with a stripper plate 5 at the upper plate surface thereof, the stripper plate is of a flat plate structure and is fixed on the base through a fixing bolt, the stripper plate is provided with two positioning pins 5a, the positioning pins are matched with positioning pin holes of a nine-number movable block A9 and a ten-number movable block A10 positioned at the lower part of the movable block die assembly A, and the stripper plate carries out auxiliary stripping on the two movable blocks during stripping.

It should be noted that in this embodiment, besides the above-mentioned stripper plate provided with the positioning pins, there is a stripper plate with a flat plate structure provided with connection holes and top thread holes, and the stripper plate is matched with the connection holes of the movable block, so that the movable block can be moved in the vertical direction, and the movable block can be used for assisting in demolding in the vertical direction. In addition, a U-shaped stripper plate may be used if translational assistance is required.

The application method of the forming die applied to the S-shaped air inlet channel with the variable cross-section structure is based on the forming die applied to the S-shaped air inlet channel with the variable cross-section structure, and the specific steps are as follows:

1) Firstly, connecting and fixing a base 1 and a core mold 2 by using a locating pin and a fixing bolt, and taking the base and the core mold as a main body structure of a mold;

2) Then, assembling each movable block of the movable block die assembly A one by one according to the assembling sequence of a tenth movable block A10, a ninth movable block A9, a eighth movable block A8, a seventh movable block A7, a first movable block A1, a second movable block A2, a third movable block A3, a fourth movable block A4, a fifth movable block A5 and a sixth movable block A6;

3) The step 2) is specifically as follows: the first movable block, the ninth movable block and the tenth movable block are sequentially arranged at the hollow position of the lower section of the core mold through positioning pins in a base groove of the base; the second movable block, the third movable block, the fourth movable block, the fifth movable block and the sixth movable block are respectively arranged at the middle section of the core mold through movable block positioning pins; the seventh movable block and the eighth movable block are arranged at the two sides of the back of the upper section of the core mold;

4) The movable blocks in the step 2) are mutually fixed with the base groove and the core mold through the connecting holes by using fixing bolts, each movable block is immediately connected after being positioned and installed, and the movable blocks and the core mold are confirmed to form preset shape positioning;

5) After all the movable blocks are installed, connecting and fixing the top of the movable block die assembly and the top of the core die by using a fixing plate 4;

6) The assembled mould is cleaned, and the mould release agent is coated, so that the forming and paving work of the S-shaped variable cross-section structure composite material air inlet channel can be carried out;

7) After the S-shaped air inlet main body structure is paved, the lips are paved, and after all the lips are paved, the lip die and the main body die are positioned and fixed by using positioning pins and bolts. Then pasting a vacuum bag on the air inlet channel according to the process file requirements, curing the air inlet channel by an autoclave and the like, and discharging and demolding after the air inlet channel is cured;

8) The stripping steps are as follows:

The method comprises the steps of firstly removing a lip die and a fixed plate at the top of the die, removing fixing bolts connected with all movable blocks, then removing all the movable blocks from a base and a core die by using a stripper plate, starting from the first movable block to the eighth movable block in the removing sequence, then connecting and fixing the ninth movable block and the tenth movable block by using the fixed plate again, vertically extracting an S-shaped air inlet channel together with the fixed plate, the ninth movable block and the tenth movable block from the base and the core die by using a truss, extracting the ninth movable block and the tenth movable block from the lower part of the air inlet channel by using the truss and the stripper plate, and finally realizing smooth demolding of the S-shaped air inlet channel, thereby obtaining the S-shaped air inlet channel with smooth and flat inner surface and S-shaped variable cross-section structure.

It will be appreciated by persons skilled in the art that the above embodiments have been provided for the purpose of illustration only and not for the purpose of limitation, and that variations and modifications of the above described embodiments will fall within the scope of the appended claims as long as they are within the true spirit of the application.

Claims (6)

1. The utility model provides a be applied to forming die of S type variable cross section structure intake duct, includes base (1), its characterized in that:

The base (1) is of a planar plate-shaped structure, the lower part of the base is provided with a foot pad (1 a), the center of the base is provided with a base groove (1 b), a core die (2) is fixedly arranged in the base groove in a vertical shape, the lower end of the core die is connected with the base groove in a connecting mode of a locating pin and a fixing bolt, and the lower section of the core die is of a hollow structure;

a movable block mold assembly (A) is arranged at the mold body of the core mold (2), each movable block of the movable block mold assembly is assembled to the base groove and the core mold in sequence, and the upper end of the movable block mold assembly is level with the upper end of the core mold;

The movable block die assembly (A) is connected with a lip die (3) by using a connecting mode of a locating pin and a fixing bolt at the upper section of the movable block die assembly (A) for locating and fixing;

the top of mandrel (2) and movable block mould subassembly (A) be provided with fixed plate (4), this fixed plate is flat plate structure, is provided with fixed connection hole (2 a) on the face of fixed plate, this fixed connection hole matches with the connecting hole at the top of mandrel and movable block mould subassembly (A), namely, should be fixed plate is connected mandrel and movable block mould subassembly through locating pin and fixing bolt's connected mode.

2. The forming die for the air inlet channel with the S-shaped variable cross-section structure according to claim 1, wherein the movable block die assembly (A) comprises a first movable block (A1), a second movable block (A2), a third movable block (A3), a fourth movable block (A4), a fifth movable block (A5), a sixth movable block (A6), a seventh movable block (A7), a eighth movable block (A8), a ninth movable block (A9) and a tenth movable block (A10), and the first movable block, the ninth movable block and the tenth movable block are sequentially arranged at a hollow position of the lower section of the core die (2) through positioning pins in a base groove (1 b) of the base (1); the second movable block, the third movable block, the fourth movable block, the fifth movable block and the sixth movable block are respectively arranged at the middle section of the core mold through movable block positioning pins; and the seventh movable block and the eighth movable block are arranged at the two sides of the back of the upper section of the core mold, and the whole movable block mold assembly is connected with the base and the core mold through the preset shape positioning.

3. A forming die for an air intake duct with an S-type variable cross-section structure according to claim 1, wherein the movable blocks of the movable block die assembly (a) are provided with grooves and connecting holes, and the corresponding positions of the base groove (1 b) and the core die (2) are also provided with connecting holes, and the movable blocks, the base groove and the core die are mutually fixed by using fixing bolts.

4. The forming die for the S-shaped variable cross-section structure air inlet channel is characterized in that lifting rings (1 c) are arranged at four corners of the upper surface of the base (1), and fork truck grooves are formed in the positions of cushion feet (1 a) arranged at the lower part of the base.

5. The forming die for the S-shaped variable cross-section structure air inlet channel, as claimed in claim 1, characterized in that the base (1) is provided with a stripper plate (5) at the upper plate surface thereof, the stripper plate is of a flat plate structure and is fixed on the base through a fixing bolt, the stripper plate is provided with two locating pins (5 a) which are matched with locating pin holes of a nine-number movable block (A9) and a ten-number movable block (A10) positioned at the lower part of the movable block die assembly (A), and the stripper plate is used for assisting in demolding of the two movable blocks during demolding.

6. A method for using a forming die for an air intake duct with an S-type variable cross-section structure, which is based on any one of claims 1 to 5, and comprises the following specific steps:

1) Firstly, connecting and fixing a base (1) and a core mold (2) by using a locating pin and a fixing bolt, and taking the base and the core mold as a main body structure of a mold;

2) Then, assembling each movable block of the movable block die assembly (A) one by one according to the assembling sequence of a tenth movable block (A10), a ninth movable block (A9), a eighth movable block (A8), a seventh movable block (A7), a first movable block (A1), a second movable block (A2), a third movable block (A3), a fourth movable block (A4), a fifth movable block (A5) and a sixth movable block (A6);

3) The step 2) is specifically as follows: the first movable block, the ninth movable block and the tenth movable block are sequentially arranged at the hollow position of the lower section of the core mold through positioning pins in a base groove of the base; the second movable block, the third movable block, the fourth movable block, the fifth movable block and the sixth movable block are respectively arranged at the middle section of the core mold through movable block positioning pins; the seventh movable block and the eighth movable block are arranged at the two sides of the back of the upper section of the core mold;

4) The movable blocks in the step 2) are mutually fixed with the base groove and the core mold through the connecting holes by using fixing bolts, each movable block is immediately connected after being positioned and installed, and the movable blocks and the core mold are confirmed to form preset shape positioning;

5) After all the movable blocks are installed, connecting and fixing the top parts of the movable block die assembly and the core die by using a fixing plate (4);

6) The assembled mould is cleaned, and the mould release agent is coated, so that the forming and paving work of the S-shaped variable cross-section structure composite material air inlet channel can be carried out;

7) After the S-shaped air inlet main body structure is paved, the lips are paved, and after all the lips are paved, the lip die (3) and the main body die are positioned and fixed by using positioning pins and bolts. Then pasting a vacuum bag on the air inlet channel according to the process file requirements, curing the air inlet channel by an autoclave and the like, and discharging and demolding after the air inlet channel is cured;

8) The stripping steps are as follows:

The method comprises the steps of firstly removing a lip die and a fixed plate at the top of the die, removing fixing bolts connected with all movable blocks, then removing all the movable blocks from a base and a core die by using a stripper plate, starting from the first movable block to the eighth movable block in the removing sequence, then connecting and fixing the ninth movable block and the tenth movable block by using the fixed plate again, vertically extracting an S-shaped air inlet channel together with the fixed plate, the ninth movable block and the tenth movable block from the base and the core die by using a truss, extracting the ninth movable block and the tenth movable block from the lower part of the air inlet channel by using the truss and the stripper plate, and finally realizing smooth demolding of the S-shaped air inlet channel, thereby obtaining the S-shaped air inlet channel with smooth and flat inner surface and S-shaped variable cross-section structure.