CN112793182B

CN112793182B - Composite material frame forming die for rack and forming method thereof

Info

Publication number: CN112793182B
Application number: CN202011507032.2A
Authority: CN
Inventors: 聂桂军; 张彬; 王源; 马婷婷; 李俊
Original assignee: Jiangsu Xinyang New Material Co ltd
Current assignee: Jiangsu Xinyang New Material Co ltd
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2023-03-14
Anticipated expiration: 2040-12-18
Also published as: CN112793182A

Abstract

The invention provides a composite material frame forming die for a rack and a forming method thereof, wherein the forming die comprises a frame forming die body and a frame forming cover plate arranged above the frame forming die body; the frame forming die comprises a frame forming die body and is characterized in that a forming area is arranged on the frame forming die body, a plurality of compaction structures are arranged in the forming area, and the compaction structures and the inner wall of the forming area jointly enclose to form a frame forming die cavity. According to the composite material frame forming die for the rack, the forming area matched with the structure of the composite material frame is arranged, so that the composite material frame with an integrated structure is prepared through hot press forming, the forming process is simplified, and the forming efficiency is improved.

Description

Composite material frame forming die for rack and forming method thereof

Technical Field

The invention relates to the technical field of composite materials, in particular to a composite material frame forming die for a rack and a forming method thereof.

Background

The frame is used as a main carrier of equipment in an aircraft cabin and is widely applied to various military aircrafts and civil aircrafts. With the improvement of the requirements of the airplane on the airplane carrying equipment, the advantages of high strength, low specific gravity and strong designability of the composite material are remarkable, and the number of the racks taking the composite material as a main raw material in the airplane is obviously increased at present.

The composite material frame is generally composed of parts such as a top/bottom frame and upright posts, wherein the top/bottom frame plays a role in lifting weight in the overall performance of the support frame, and the quality of top/bottom forming directly influences the stability and strength of the overall frame.

The top/bottom frame forming process of the existing rack is to form a plurality of composite parts in advance, and a top/bottom frame structure is formed among the composite parts in a glue riveting process; the forming mode of the top/bottom frame structure has the disadvantages of more parts, complex forming process and low forming efficiency.

Disclosure of Invention

The invention solves the problem that the forming efficiency of the prior top/bottom frame structure is low.

In order to solve the above problems, the present invention provides a composite material frame forming mold for a rack, which includes a frame forming mold body, and a frame forming cover plate disposed above the frame forming mold body; the frame forming die comprises a frame forming die body and is characterized in that a forming area is arranged on the frame forming die body, a plurality of compaction structures are arranged in the forming area, and the compaction structures and the inner wall of the forming area jointly enclose to form a frame forming die cavity.

Optionally, the compression structure comprises a PMI foam, and a silicone rubber compression layer disposed about the periphery of the PMI foam.

Optionally, the thickness of the silicone rubber compacted layer ranges from 15mm to 25mm.

Optionally, the compacted structure further comprises a steel plate layer arranged at the periphery of the silicon rubber compacted layer.

Optionally, the thickness of the steel plate layer ranges from 1mm to 5mm.

Optionally, the number of the compacting structures is four, and the four compacting structures and the inner wall of the forming area jointly enclose the frame forming mold cavity with the grid-shaped structure.

Optionally, the corner of the frame forming mold body is provided with a second positioning groove distributed along the vertical direction, and a second positioning claw matched with the second positioning groove.

Another object of the present invention is to provide a molding method of a composite frame for a rack, which uses the composite frame molding die for a rack as described above for molding;

the molding method comprises the following steps:

s1: preparing a skeleton having an integral structure;

s2: paving and pasting the prepreg paving layer on the framework with the integrated structure to obtain a paved framework;

s3: and placing the paved frame in the frame molding die cavity of the frame molding die, and curing and molding through a hot press to obtain the composite material frame.

Optionally, the preparing the skeleton with the integrated structure comprises preparing the skeleton with the integrated structure by heating and foaming by using a skeleton forming mold;

utilize skeleton forming die, through the mode preparation that heats the foaming that has integral type structure the skeleton includes:

s11: connecting the tee joint with a foam core with a grid-shaped structure;

s12: coating foaming glue at the joint of the tee joint and the foam core to obtain a glue joint framework;

s13: and placing the glued joint framework in the framework forming die, and preparing the framework with an integrated structure by heating and foaming.

Optionally, the framework forming mold comprises a framework forming base and a framework forming cover plate arranged above the framework forming base; a framework forming area is arranged on the framework forming base, a framework forming groove shaped like a Chinese character 'tian' is arranged in the framework forming area, and the framework forming groove is used for placing the foam core; four corners of skeleton shaping base all be provided with skeleton shaping recess looks vertically first constant head tank, and with the first positioning claw of first constant head tank looks adaptation.

Compared with the prior art, the composite material frame forming die for the rack provided by the invention has the following advantages:

according to the composite material frame forming die for the rack, the forming area matched with the structure of the composite material frame is arranged, so that the composite material frame with an integrated structure is prepared through hot press forming, the forming process is simplified, the forming efficiency is improved, the mechanical strength of the composite material frame is improved due to the fact that all parts are of the integrated structure, the stability and the strength of the whole rack are improved, and the rack is further beneficial to further reducing the weight of the rack on the basis that the rack meets the mechanical requirements.

Drawings

FIG. 1 is a schematic view of a frame forming mold according to the present invention;

FIG. 2 is a schematic view of the frame forming die body according to the present invention;

fig. 3 is an exploded view of the frame forming mold according to the present invention;

fig. 4 is an exploded view of the frame forming mold according to the present invention;

fig. 5 is an exploded view of a frame molding die according to the present invention;

FIG. 6 is a schematic view of the frame of the present invention;

FIG. 7 is a schematic view of a framework forming mold according to the present invention;

FIG. 8 is a schematic view of the structure of the adhesive bonded frame of the present invention;

FIG. 9 is a schematic view of + -45 deg. and 90 deg. plies of the present invention;

FIG. 10 is a schematic view of a 0 ° ply according to the present invention;

FIG. 11 is a graph of the curing temperature during the curing process of the present invention;

FIG. 12 is a flow chart of the tee forming process of the present invention.

Description of reference numerals:

1-a frame forming die body; 11-compacting the structure; 111-PMI foam; 112-a silicone rubber compacted layer; 113-a steel deck; 12-a frame molding cavity; 13-a second positioning groove; 14-a second positioning pawl; 2-forming a cover plate on the frame; 21-a first cover plate; 22-a second cover plate; 23-a third cover plate; 3-a composite frame; 4-framework forming die; 41-framework forming base; 411-skeleton forming grooves; 412-a first detent; 413-a first positioning claw; 42-framework molding cover plates; 5-gluing a framework; a 51-tee; 52-foam core.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and intended to be illustrative of the present invention and should not be construed as limiting the present invention, and all other embodiments that can be obtained by one skilled in the art based on the embodiments of the present invention without inventive efforts shall fall within the scope of protection of the present invention.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "circumferential," "radial," and the like are used in the orientations and positional relationships indicated in the drawings for the purpose of simplifying the description, and are not intended to indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be considered as limiting the present invention.

Furthermore, the terms "first" and "second" are used merely to simplify the description and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the first feature being "on" or "under" the first feature may comprise the first feature being in direct contact with the second feature or the first feature being in direct contact with the second feature but being in contact with the second feature by another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. The first feature being "under," "below," and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or merely indicates that the first feature is at a lower level than the second feature.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

Due to the particularity of the aircraft frame structure, the frame structure positioned at the top or the bottom of the frame, namely the top/bottom frame comprises a plurality of rod-shaped structures which are connected in a staggered manner to form the frame structure; meanwhile, hollow structures are arranged among the rod-shaped structures forming the frame structure; therefore, in the forming process of the composite material frame positioned at the top or the bottom of the rack, various rod-shaped structures and other parts need to be formed firstly, and then all the parts are connected through a glue riveting process, so that the forming efficiency is low, and meanwhile, the stability and the strength of the whole rack are influenced due to the limited connection strength among all the parts.

In order to solve the problem of low forming efficiency of the existing top/bottom frame structure, the invention provides a composite material frame forming die for a rack, as shown in fig. 1-5, the frame forming die comprises a frame forming die body 1 and a frame forming cover plate 2 arranged above the frame forming die body 1, and a composite material frame 3 is formed by covering the frame forming cover plate 2 on the frame forming die body 1; the frame forming die body 1 is provided with a forming area, and the structure of the forming area is matched with that of the composite material frame 3 and is used for forming the corresponding composite material frame 3; specifically, a plurality of compacting structures 11 are arranged in the forming area, and the compacting structures 11 and the inner wall of the forming area jointly enclose to form a frame forming die cavity 12.

Because the composite material frame 3 is provided with the hollow structure, in order to facilitate compaction of the structure inside the composite material frame 3, the forming area is internally provided with a plurality of compaction structures 11, wherein the number, the shape, the distribution and other conditions of the compaction structures 11 are matched with the structure inside the composite material frame 3, a frame forming die cavity 12 is formed by jointly enclosing the plurality of compaction structures 11 and the inner wall of the forming area, and the frame forming die cavity 12 is of a groove structure matched with the shape structure of the composite material frame 3; during molding, the laid frame is placed in the frame molding die cavity 12, the frame molding cover plate 2 and the frame molding grinding tool body 1 are covered, and the covered frame molding grinding tool is placed in a hot press for hot pressing and curing.

According to the composite material frame forming die for the rack, the forming area matched with the structure of the composite material frame 3 is arranged, so that the composite material frame 3 with an integrated structure is prepared through hot press forming, the forming process is simplified, the forming efficiency is improved, the mechanical strength of the composite material frame is improved due to the fact that all parts are of the integrated structure, the stability and the strength of the whole rack are improved, and the weight of the rack is further reduced on the basis that the mechanical requirement of the rack is met.

In addition, as the frame forming die cavity 12 is formed by enclosing the compaction structure 11 and the inner wall of the forming area together, in the hot press forming process, the compaction structure 11 is positioned at the hollow part in the composite material frame 3, the periphery of the compaction structure 11 is contacted with the inner structure of the composite material frame 3, so that the inner structure of the composite material frame 3 is compacted through the compaction structure 11 in the forming process; in the hot-pressing curing process, the internal structure of the composite material frame 3 is compacted by the plurality of compacting structures 11 positioned in the forming area, so that the prepared composite material frame has lower internal stress, the composite material frame has small warpage deformation after demoulding, and the mechanical property is more stable.

Wherein the composite frame 3 in the present application may be either a top frame or a bottom frame of the rack.

Because the top frame and the bottom frame of frame all are the outward appearance face of product with the surface, have than high apparent dimension requirement, the preferred frame forming die of this application is the steel mould, or the inner wall of frame shaping die cavity 12 is steel material to guarantee the roughness of 3 surface of combined material frames.

The composite material frame forming die is used for heating and pressurizing a formed product in the closed frame forming die cavity 12, so that the loss of raw materials is small in the forming process, excessive raw material waste is avoided, and the cost is reduced; meanwhile, the abrasion of the frame molding die cavity 12 is small, the maintenance cost of the frame molding die is low, and the prepared composite material frame 3 is low in shrinkage rate and good in repeatability; the prepared composite material frame 3 has high dimensional precision and smooth surface, does not need secondary modification, and can directly monitor the surface quality, the member thickness, the porosity and the like of the composite material frame 3.

To facilitate the compaction of the structure inside the composite frame 3 during the hot press curing process, referring to fig. 2, the preferred compacted structure 11 of the present application comprises a PMI foam 111, and a silicone rubber compacted layer 112 disposed at the periphery of the PMI foam 111.

By designing the compaction structure 11 into a structural form that the PMI foam 111 is filled in the silicone rubber compaction layer 1112, in the hot-pressing curing process, the PMI foam 111 and the silicone rubber compaction layer 112 expand after being heated, and in the expansion process, the pressure is transmitted to the internal structure of the composite material frame 3 in contact with the compaction structure 11, so that the internal structure of the composite material frame 3 is compacted, the internal stress of the composite material frame 3 is reduced, and the stability of the mechanical performance is improved.

Specifically, in combination with the expansion amount of the PMI foam 111 and the silicone rubber compacted layer 112 in the hot press curing process, for example, the expansion amount is 5% to 6% at 180 ℃, in order to ensure the compacting effect, the thickness range of the silicone rubber compacted layer 112 is preferably 15mm to 25mm, and the thickness of the silicone rubber compacted layer 112 is further preferably 20mm.

Further, in order to improve the aesthetic measure of the surface of the composite material frame 3, the preferred compacted structure 11 of the present application further includes a steel plate layer 113, the steel plate layer 113 is disposed at the periphery of the silicone rubber compacted layer 112, so that in the hot-pressing curing process, the steel plate layer 113 is directly contacted with the internal structure of the composite material frame 3, in the hot-pressing expansion process, the pressure is sequentially transmitted to the steel plate layer 113 from the PMI foam 111 and the silicone rubber compacted layer 112, and the internal structure of the composite material frame 3 is compacted through the steel plate layer 113, so as to improve the smoothness of the external surface of the composite material frame 3, and improve the product quality.

The thickness of the steel deck 113 is preferably in the range of 1mm to 5mm, and the thickness of the steel deck 113 is more preferably 3mm.

Referring to fig. 6, the top/bottom of the composite material frame 3 is preferably in a grid-like structure, and correspondingly, the number of the compaction structures 11 is preferably four, and the four compaction structures 11 and the inner wall of the forming area jointly enclose a frame forming mold cavity 12 with a grid-like structure.

Frame is including the frame construction that is located both ends from top to bottom usually, and the stand that links to each other top frame and bottom frame, composite frame 3 for will preparing links to each other with the stand, the edge of the frame forming die body 1 that this application provided is provided with along the second constant head tank 13 that vertical direction distributes, and with the second positioning claw 14 of second constant head tank 13 looks adaptation, positioning action through second constant head tank 13 and second positioning claw 14, make composite frame 3 of preparation include the three connecting portion that link to each other with the stand, thereby reduce the degree of difficulty that links to each other composite frame 3 and stand, improve the stability of the whole mechanical properties of frame simultaneously.

Further, in order to ensure the molding effect, the frame molding cover plate 2 preferably comprises a first cover plate 21, a second cover plate 22 and a third cover plate 23 which are sequentially arranged from inside to outside, wherein the shapes and the respective materials of the three cover plates are determined according to the respective positions, so that the frame molding cover plate 2 is better matched with the frame molding mold body 1 and the stress characteristics in the molding process; the first cover plate 21 is preferably a silicon rubber compression plate with the thickness of 20mm; the second cover plate 22 is a steel plate having a thickness of 3mm; the third cover plate 23 may be made of steel plate or other material.

Another object of the present invention is to provide a molding method of a composite frame for a rack, which uses the composite frame molding die for a rack as described above for molding; the specific forming method comprises the following steps:

s1: preparing a skeleton having an integral structure;

s3: and placing the paved frame in a frame molding die cavity 12 of a frame molding die, and curing and molding through a hot press to obtain the composite material frame 3.

The framework of the integrated structure is selected, so that the mechanical property of the composite material framework 3 is improved.

In order to meet the requirements on strength, light weight, high temperature and low pressure resistance and other properties of the prepared composite material frame 3, the framework with an integrated structure is preferably selected, XK-110PMI foam is selected, and the foam can have compressive strength of 0.4Mpa at a high temperature of 180 degrees; and preferably the prepreg is laminated into a high-temperature epoxy carbon fiber composite material system with T700/E1802 and T300/E1802.

In addition, for guaranteeing the coordination of 3 whole mechanics performances of combined material frame, spread the in-process to the prepreg shop layer, the shop layer direction that this application prefers unidirectional cloth shop layer is: 50% of 0-degree direction ply, 15% of plus or minus 45-degree direction ply and 20% of 90-degree direction ply. When paving plus or minus 45-degree and 90-degree paving layers, wrapping is carried out along the circumferential direction as shown in fig. 9, and paving is not carried out at the crossing position; in the 0 ° orientation, the lay down is done axially, as shown in fig. 10, creating a repeat lay down of two layers of fibers at the intersection.

In the specific paving and pasting process, drawing the appearance of each layer of fiber prepreg by using drawing software according to different areas, and introducing the appearance into an operating system of an automatic blanking machine; cutting each prepreg sheet by an automatic blanking machine according to a program, and marking each sheet; laying according to a designed laying sequence, in order to enable fiber fabrics to be tightly attached and remove air between the fabrics, the laid fabrics are wrapped by a vacuum bag, the vacuum bag is vacuumized at normal temperature, and the fabrics are compacted by utilizing vacuum pressure; in the optimal paving and pasting process of the application, when four layers of prepreg are paved, compaction is carried out for 15min until all prepreg sheets are paved and pasted.

Before curing and forming, processing a frame forming die; specifically, cleaning paper or a clean rag is used for cleaning up sundries such as residual resin in the frame molding die cavity 12, and the cleaning paper is used for dipping acetone to clean the working surface of the die; coating 770NC mold release agent on the surface of the cavity for 5 times, wherein coating omission positions cannot be caused, and the interval time between each time is not less than 15 minutes; after the last mold release is coated, the frame forming mold is placed into an oven and cured for 30min at 120 ℃.

Placing the laid frame in a frame forming die body 1, covering a cover plate 2, and installing a second positioning claw 14 to finish the assembly of the frame forming die; placing the assembled frame forming die in a high-temperature hot press, and performing hot-pressing solidification; the relevant parameters in the specific hot press curing process are shown in fig. 11.

After the solidification is finished, closing the hot press, and demolding after the temperature of the frame forming mold is reduced to below 60 ℃; in the demolding process, the cover plate 2 and the second fixing claw 14 on the frame molding mold are dismounted firstly, and finally the molded composite material frame 3 is taken out through structures such as a base sliding block and the like.

After the composite material frame 3 is taken out, burrs and resin-rich areas on the edges of the product are further removed by polishing with 800# abrasive paper, and then the product is polished smoothly with 1000# waterproof abrasive paper, so that fibers are not allowed to be damaged during polishing, and the attractiveness of the product is improved.

The preparation of the skeleton with an integrated structure in the present application includes, as shown in fig. 7, preparing the skeleton with an integrated structure by heating and foaming using a skeleton-forming mold 4.

Specifically, referring to fig. 8, the preparation of the skeleton having an integrated structure by heating and foaming using the skeleton-forming mold 4 includes:

s11: connecting the tee joint 51 with a foam core 52 with a grid-shaped structure;

s12: coating foaming glue at the joint of the tee joint 51 and the foam core 52 to obtain a glue joint framework 5;

s13: and placing the glued joint framework 5 in a framework forming die 4, and heating and foaming to prepare the framework with the integrated structure.

Referring to fig. 8, the number of the tees 51 is four, four tees 51 are respectively arranged at four corners of the framework, each tee 51 comprises three mutually perpendicular connecting ends, two of the connecting ends are connected with the foam core 52 shaped like a Chinese character tian, and the other connecting end is used for forming a connecting part of the composite material frame 3 and is used for connecting with a stand column; the tee joint 51 can be obtained by molding a silicon rubber mold core and a steel outer mold; the process of forming the three-way valve 51 is shown in FIG. 12.

In the preferred tee bend 51 forming process of this application, the silicon rubber that uses is R-10301 of middle-blue morning light, two ingredients, and normal proportion is 10:1, can be according to outdoor temperature in good time adjustment, if summer temperature is high can few strengthening agent, the proportion adjustment is 11:1.

cutting the tee joint 51 to a required size, connecting the formed tee joint 51, the foam core 52 and the corresponding embedded part through J-118 strip-shaped foaming structural adhesive to obtain an adhesive joint framework 5, placing the adhesive joint framework 5 into a framework forming mold 4 for assembly, placing the assembled framework forming mold 4 into an oven, and taking out the assembled framework forming mold after foaming is completed.

This application has the integral type structure through the skeleton of the mode preparation of foaming of heating to help improving the mechanical properties of the combined material frame of preparation.

Specifically, referring to fig. 7, the framework forming mold 4 in the present application includes a framework forming base 41, and a framework forming cover plate 42 disposed above the framework forming base 41; a framework forming area is arranged on the framework forming base 41, a framework forming groove 411 in a shape of a Chinese character tian is arranged in the framework forming area, and the framework forming groove 411 is used for placing the foam core 52; the four corners of the framework forming base 41 are provided with first positioning grooves 412 perpendicular to the framework forming grooves 411 and first positioning claws 413 matched with the first positioning grooves 412.

When the skeleton is molded, the foam core 52 is placed in the skeleton molding groove 411, and the tee 51 is positioned through the first positioning groove 412 and the first positioning claw 413, so that the structure is simple and the operation is easy.

Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and such changes and modifications will fall within the scope of the present invention.

Claims

1. The composite material frame forming die for the machine frame is characterized by comprising a frame forming die body (1) and a frame forming cover plate (2) arranged above the frame forming die body (1); the frame forming die comprises a frame forming die body (1), wherein a forming area is arranged on the frame forming die body (1), a plurality of compaction structures (11) are arranged in the forming area, and the compaction structures (11) and the inner wall of the forming area jointly enclose to form a frame forming die cavity (12);

during the hot-press forming process, the compaction structure (11) is positioned in the hollow part of the composite material frame (3), the periphery of the compaction structure (11) is in contact with the internal structure of the composite material frame (3), so that the internal structure of the composite material frame (3) is compacted through the compaction structure (11) during the forming process;

the compact structure (11) comprises a PMI foam (111) and a silicone rubber compact layer (112) arranged at the periphery of the PMI foam (111);

the thickness range of the silicon rubber compaction layer (112) is 15 mm-25 mm.

2. A composite frame moulding mould for a machine frame according to claim 1, characterised in that the compacting structure (11) further comprises a steel deck (113), the steel deck (113) being arranged at the periphery of the silicon rubber compacting layer (112).

3. The composite frame molding die for a machine frame as claimed in claim 2, wherein the thickness of the steel plate layer (113) ranges from 1mm to 5mm.

4. A composite frame forming tool for a frame according to any one of claims 1 to 3, characterised in that the number of the compacting structures (11) is four, and that four compacting structures (11) and the inner wall of the forming area together enclose the frame forming cavity (12) having a grid-like structure.

5. A composite frame moulding mould for a rack according to claim 4, characterized in that the frame moulding mould body (1) is provided with second positioning slots (13) distributed in the vertical direction at the corners and second positioning claws (14) adapted to the second positioning slots (13).

6. A method for molding a composite frame for a machine frame, characterized in that the composite frame molding die for a machine frame according to any one of claims 1 to 5 is used for molding;

the molding method comprises the following steps:

s1: preparing a skeleton having an integral structure;

s3: and placing the laid frame in the frame molding die cavity (12) of the frame molding die, and curing and molding through a hot press to obtain the composite material frame (3).

7. The molding method of composite material frame for rack as set forth in claim 6, wherein preparing a skeleton having an integral structure comprises preparing the skeleton having an integral structure by means of warm foaming using a skeleton-molding die (4);

utilize skeleton forming die (4), through the mode preparation that heats the foaming that has the integral type structure the skeleton includes:

s11: connecting the tee joint (51) with a foam core (52) with a grid-shaped structure;

s12: coating foaming glue at the joint of the tee joint (51) and the foam core (52) to obtain a glue joint framework (5);

s13: placing the glued joint framework (5) in the framework forming mold (4), and preparing the framework with an integrated structure through heating and foaming.

8. The method of claim 7, wherein the skeleton-forming die (4) comprises a skeleton-forming base (41), and a skeleton-forming cover plate (42) disposed over the skeleton-forming base (41); a framework forming area is arranged on the framework forming base (41), a framework forming groove (411) shaped like a Chinese character tian is arranged in the framework forming area, and the framework forming groove (411) is used for placing the foam core (52); four corners of skeleton shaping base (41) all be provided with skeleton shaping recess (411) looks vertically first constant head tank (412), and with first constant head tank (413) of (412) looks adaptation.