CN116001312A - A method of manufacturing a slender carbon fiber composite material square tube structure - Google Patents

Abstract

The invention discloses a manufacturing method of a square tube structural member made of an elongated carbon fiber composite material, which comprises the following steps: the first step: preparing a die: s2: paving and positioning: s3: paving carbon fiber prepreg: s4: and (3) curing and forming parts: s5: and (3) releasing equalizing plates 21 and 22: s6: removing the paving male die: s7: and (3) part detection: s8: and (5) trimming the parts. The invention ensures the precision requirements of the inner and outer molded surfaces of the product, ensures the stability of the demolding quality of the product, adopts flanging for paving in the process of paving the carbon fiber prepreg, plays a role in assisting demolding of the subsequent product, and can slowly demold the male mold by the threaded rod through flanging around the product supported by the ejector rod and the ejector block in the auxiliary tool; after the male die and the slender carbon fiber composite square tube structural member are formed by heating, due to the principles of thermal expansion and cold contraction of the two materials in the curing process, a micro gap can be formed between the inner molded surface of the carbon fiber and the steel male die, and the male die can be slowly pulled out by an auxiliary tool conveniently.

Description

A method of manufacturing a slender carbon fiber composite material square tube structure

technical field

The invention belongs to the technical field of composite material processing, and relates to a method for manufacturing a square tube structural part of a slender carbon fiber composite material.

Background technique

Carbon fiber composite materials have been widely used in aerospace products due to their advantages of light weight, high strength, non-corrosion, convenient molding, and beautiful quality. The structure of composite material parts tends to be simple and lightweight; The material molding process is quite difficult, and one of the slender composite tubular structural parts (see Figure 1) belongs to this type of structure; the composite material part structure is a slender carbon fiber composite square tube structural part, and the thickness around the product is Equal thickness, the inner cavity size is small; the size is (50×60) mm; the length is about 1000mm, the inner and outer surfaces of the slender carbon fiber composite square tube structure are required to be flat, especially the inner surface is followed by the assembly relationship of connectors, assembly The requirements for precision dimensions are high, and the composite carbon fiber structural parts mainly rely on fibers to transmit loads, so grinding and repairing is not allowed in the assembly area, and the dimensional accuracy of the inner surface of the assembly area is high. The inner surface of the carbon fiber composite square tube structural part must be shaped by a mold to ensure that the size of the inner surface meets the assembly requirements. However, due to the structural square tube structural part of the part, the existing composite material manufacturing process is relatively complicated; mainly reflected In terms of product demoulding methods, in order to ensure the structural requirements, the existing molding methods mainly include the following methods:

1. Using positive mold molding, the risk of this method is that during the part demoulding process, due to the small size of the inner cavity of the part, the slender structural parts, and the product and the male mold are heated and formed at high temperature and high pressure, the product and the mold are relatively close; The existing molding method cannot separate the product from the male mold, resulting in quality problems that the product cannot be demolded;

2. Using female molding, the risk of this method is that the size of the outer surface can be guaranteed, but according to the requirements of the inner surface and the size of the R corner area required by the product, the female molding method cannot guarantee the requirements, and the subsequent assembly of the product The matching accuracy requirements cannot be guaranteed;

3. Elastomer molds are used; male and female molds are used for forming, and the male molds are replaced by expansion mandrels or airbag mandrels. They are inflated with an external inflation source to make them expand, and the pressure is transmitted to the surface of the laminate. This kind of molding The risk of forming the slender carbon fiber composite square tube structural parts is that the forming requirements for the airbag mandrel are high, the airbag mandrel needs to be formed separately, the production combination process is complicated, and the production cost is increased;

Under such a technical background, for this slender carbon fiber composite square tube structure, the product has a simple shape, light weight, smooth inner and outer surfaces, and the size of the inner surface meets the requirements of assembly accuracy. cost, improve the stability of product quality; a breakthrough must be made in the existing molding process; the present invention adopts male die paving, and the outer surface uses pressure equalizing plate molding die to combine molding, and the premise of ensuring product quality is to use stripping Mold-assisted tooling is used to demould the product; this technical method completes the manufacture of slender carbon fiber composite square tube structural parts, better improves the quality of parts, and ensures the assembly accuracy and size requirements of the product's inner surface.

Contents of the invention

The purpose of the present invention is to provide a method for manufacturing a slender carbon fiber composite material square tube structure, so as to improve the quality of the parts, ensure the assembly accuracy and size requirements of the inner surface of the product, and improve production efficiency.

Technical scheme of the present invention:

A method for manufacturing a slender carbon fiber composite material square tube structure, the steps of the method are as follows:

S1: Prepare the mold:

Make paving and pasting male mold, pressure equalizing plate forming mold and demoulding auxiliary tooling, wherein, one end of paving and pasting male mold has a threaded connection hole, and said pressure equalizing plate forming mold is composed of left half pressure equalizing plate and right half pressure equalizing plate, in the left half Pave expanded rubber on the molding surface of the equalizer plate and the right half equalizer plate, assemble and seal after the paving is completed, and cure and mold according to the vulcanization parameters; obtain the left half equalizer plate and the right half equalizer plate with expanded rubber; the demoulding Auxiliary tooling includes a jacking block, a jacking rod, a threaded seat block, a threaded wrench and a threaded rod. Rod, one end of the threaded rod is connected with a threaded wrench, and the other end of the threaded rod passes through the center hole of the top block to cooperate with the threaded connection hole;

S2: Paving positioning:

Combine the top block with the paving male mold so that the top block is positioned at one end of the paving male mold;

S3: laying carbon fiber prepreg:

Lay the carbon fiber prepreg on the paving male mold, except for the forming part, pave the four sides along the side of the top block to get the prepreg carbon fiber square tube;

S4: Part curing molding:

Lay a layer of release cloth and isolation film on the surface of the prepreg carbon fiber square tube, combine the left half pressure equalizing plate and the right half pressure equalizing plate with expansion rubber on the prepreg carbon fiber square tube, and then heat the The process of the pressure pot forming method requires vacuum hot pressing to obtain a molded part;

S5: Forming mold for de-equalizing plate:

After curing and forming, remove the left and right equalizing plates, and loosen the top block;

S6: Take off the pavement and stick the male mold:

Pass one end of the threaded rod through the center hole of the top block and connect it to the threaded connection hole of the paving male mold, so that the ejector rod withstands the top block, and the threaded rod pushes the paving male mold to separate from the part forming body by turning the threaded wrench. complete demoulding;

S7: Part detection:

Carry out non-destructive testing inspection of the molded parts;

S8: Trim parts:

According to the relevant technical conditions, the molded body of the part is processed and trimmed to obtain a slender carbon fiber composite material square tube structural part.

Further, the surface of the equalizing plate forming mold is enlarged by 0.12 mm on each surface based on the external surface of the carbon fiber square tube part.

Further, the combination surface of the left half pressure equalizer plate and the right half pressure equalizer plate is a stepped combination surface.

Further, the upper surface of the left half pressure equalizing plate is provided with a first outer concave platform, the lower surface is provided with a first inner concave platform, and the upper surface of the right half pressure equalizing plate is provided with a second concave platform that matches the first outer concave platform. The inner concave platform has a second outer concave platform matching the first inner concave platform on the lower surface.

Furthermore, in S3, the thickness of the flanging paving is 1.5 to 2.5 times the thickness of the elongated carbon fiber composite square tube structural part.

Further, the threaded rod has a length of 1100mm and a diameter of 20mm.

Beneficial effects of the present invention:

In order to ensure the assembly accuracy requirements of the inner surface of the product, the present invention adopts a paving male mold for forming. In order to ensure that the outer surface of the part has a smooth surface quality, a set of pressure equalizing plate forming molds is customized. In order to ensure the stability of the demoulding quality of the product In order to ensure that the product can be demoulded smoothly around the product, the product is paved with flanging during the paving process, which plays the role of auxiliary demoulding for subsequent products. Through the ejector pin and the top block in the auxiliary tooling Withstand the flanging around the product, so that the threaded rod can slowly demould the male mold; after the male mold and the slender carbon fiber composite square tube structure are formed by heating, due to the principle of thermal expansion and contraction of the two materials during the curing process, A small gap will be formed between the carbon fiber inner surface and the steel male mold, which will facilitate the auxiliary tooling to slowly release the male mold; through a series of subsequent tests on the carbon fiber composite structural parts, it is proved that the product quality meets the relevant technical requirements.

Description of drawings

Fig. 1 is the structural schematic diagram of the slender carbon fiber composite material square tube structure;

Fig. 2 is the schematic diagram of paving and pasting male mold in the embodiment of the present invention;

Fig. 3 is the schematic diagram of the molding die of equalizing plate in the embodiment of the present invention;

Fig. 4 is a schematic structural view of demoulding auxiliary tooling in an embodiment of the present invention;

Fig. 5 is another structural schematic diagram of the demoulding auxiliary tooling in the embodiment of the present invention;

Fig. 6 is a combined schematic view of the pressure equalizing plate molding die in the embodiment of the present invention;

Fig. 7 is the paving schematic diagram of the embodiment of the present invention;

Fig. 8 is the demoulding schematic diagram of the embodiment of the present invention;

Fig. 9 is a schematic diagram of flanging cutting according to an embodiment of the present invention;

In the figure: paving male mold 1, pressure equalizing plate forming mold 2, demoulding auxiliary tooling 3, prepreg carbon fiber square tube 4, flange cut 5, threaded connection hole 11, left equalizing plate half 21, right half equalizing plate 22 , top block 31, ejector rod 32, threaded seat block 33, threaded wrench 34, threaded rod 35, flange 41, the first outer concave platform 211 of the left half pressure equalizing plate, the first inner concave platform 212 of the left half pressure equalizing plate, the right half The second inner concave platform 221 of the pressure equalizing plate, and the second outer concave platform 222 of the right half pressure equalizing plate.

Detailed ways

The present invention can be further described by the following examples, however, the scope of the present invention is not limited to the following examples.

Embodiment: As shown in Fig. 1, a kind of manufacturing method of elongated carbon fiber composite material square tube structure, the steps of this method are as follows:

S1: Prepare the mold:

First of all, in order to ensure that the dimensional accuracy of the internal surface assembly of the slender carbon fiber composite square tube structure meets the requirements, a paving male mold 1 (see Figure 2) is customized. One end of the paving male mold 1 has a threaded connection hole 11; in order to ensure that the parts The outer surface of the pressure equalizing plate has a flat surface quality, and a set of pressure equalizing molding die 2 and soft expansion rubber mold after molding are customized (see Figure 3 and Figure 6). On the basis of the exterior surface, each surface is enlarged by 0.12mm. The equalizing plate is composed of the left half equalizing plate 21 and the right half equalizing plate 22. The expansion rubber is laid on the left half equalizing plate 21 and the right half equalizing plate 22, and the paving is completed. Finally, assemble and seal according to the requirements of relevant process documents, and then use relevant heating equipment to perform curing and molding according to the vulcanization parameters of the soft mold, and obtain the left half equalizing plate 21 and the right half equalizing plate 22 with expanded rubber, wherein, the left half The combined surface of the pressure equalizing plate 21 and the right half of the pressure equalizing plate 22 is a stepped combination surface, the upper surface of the left half of the pressure equalizing plate 21 is provided with a first outer concave platform 211, and the lower surface is provided with a first inner concave platform 212. The upper surface of the pressure equalizing plate 22 is provided with a second inner concave platform 221 matched with the first outer concave platform 211, and the lower surface is provided with a second outer concave platform 222 matched with the first inner concave platform 212; in order to ensure that the elongated carbon fiber composite The material square tube structure was successfully demoulded, and a set of auxiliary demoulding tooling was customized (see Figure 4 and Figure 5). Rod 35, wherein, jacking block 31 is the part that cooperates to use, described threaded seat block 33 sides are respectively provided with ejector bar 32, and threaded seat block 33 is equipped with threaded rod 35, and one end of threaded rod 35 is connected with threaded wrench 34. The other end of the threaded rod 35 passes through the center hole (not shown in the figure) of the top block 31 to cooperate with the threaded connection hole 11.

S2: Paving positioning:

Combine the jacking block 31 with the paving male mold 1, so that the jacking block 31 is positioned at one end of the paving male mold 1; specifically, the jacking block 31 can be fixed at one end of the male paving tooling with double-sided adhesive (see Figure 7) .

S3: laying carbon fiber prepreg:

According to the relevant requirements of the slender carbon fiber composite material square tube structural parts, the carbon fiber prepreg is laid on the laying male mold 1. During the laying process, the flanging 41 around the top block 31 needs to be laid as a whole to obtain the prepreg carbon fiber. The square tube 4; the thickness of the flanging 41 is 1.5 to 2.5 times the thickness of the slender carbon fiber composite square tube structure, preferably 2 times the thickness. By setting the flanging 41, the load can be transferred, which is conducive to the development of subsequent products. Unmold, (see Figure 7).

S4: Part curing molding:

Lay a layer of release cloth and isolation film on the surface of the prepreg carbon fiber square tube 4, and combine the left half pressure equalizing plate 21 and the right half pressure equalizing plate 22 with expanded rubber to press on the prepreg carbon fiber square tube 4, and then According to the general process requirements of the autoclave forming method of composite materials, the vacuum bag process combination operation is carried out; according to the process parameters of the carbon fiber prepreg, it is heated and cured in an autoclave to obtain a molded part.

S5: Forming mold for de-equalizing plate:

Remove the vacuum bag and equalize the left half of the pressure equalizing plate 21 and the right half of the pressure equalizing plate 22; loosen the end of the top block 31 close to the molded body of the part, and ensure that the top block 31 and the paving male mold 1 are in a loose state (see Figure 8);

S6: Take off the pavement and stick the male mold:

Pass one end of the threaded rod 35 through the center hole of the top block 31 and connect it to the threaded connection hole 11 of the paving male mold 1, so that the ejector rod 2 withstands the top block 31, and the threaded rod 35 is pushed by turning the threaded wrench 34 The male mold 1 is separated from the molded body of the part to complete demoulding;

S7: Part detection:

Carry out non-destructive testing inspection of the molded parts;

S8: Trim parts:

The product is processed and trimmed according to the relevant technical conditions (refer to Figure 9 to cut off the end of the part molded body with flanging), and a slender carbon fiber composite material square tube structural part is obtained.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and without departing from the spirit or basic principles of the present invention. The present invention can be embodied in other specific forms without using the features described above. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (6)

1. A manufacturing method of a slender carbon fiber composite square tube structural member is characterized by comprising the following steps: the method comprises the following steps:

s1: preparing a die:

manufacturing a paving male die, a uniform pressure plate forming die and a demolding auxiliary tool, wherein one end of the paving male die is provided with a threaded connection hole, the uniform pressure plate forming die consists of a left half uniform pressure plate and a right half uniform pressure plate, expanded rubber is paved on forming surfaces of the left half uniform pressure plate and the right half uniform pressure plate, assembly sealing is carried out after paving is completed, and curing molding is carried out according to vulcanization parameters; obtaining a left half equalizing plate and a right half equalizing plate with expanded rubber; the demolding auxiliary tool comprises a jacking block, an ejector rod, a threaded seat block, a threaded wrench and a threaded rod, wherein the jacking block is a matched part, the ejector rod is arranged around one side of the threaded seat block respectively, the threaded seat block is provided with the threaded rod, one end of the threaded rod is connected with the threaded wrench, and the other end of the threaded rod penetrates through a central hole of the jacking block to be matched with the threaded connecting hole;

s2: paving and positioning:

combining the top block with the paving male die to enable the top block to be positioned at one end of the paving male die;

s3: paving carbon fiber prepreg:

spreading the carbon fiber prepreg on a spreading male die, and spreading the carbon fiber prepreg along the side edge of the top block towards the periphery except the forming part during spreading to obtain a prepreg carbon fiber square tube;

s4: and (3) curing and forming parts:

paving a layer of release cloth and an isolating film on the surface of the prepreg carbon fiber square tube, combining a left half-equalizing plate and a right half-equalizing plate with expansion rubber on the prepreg carbon fiber square tube, and then carrying out vacuum hot-press molding according to the technological requirements of a composite material autoclave molding method to obtain a part molded body;

s5: and (3) removing the equalizing plate forming die:

removing the left half uniform pressure plate and the right half uniform pressure plate after solidification molding, and loosening the top block;

s6: removing the paving male die:

one end of the threaded rod penetrates through the center hole of the ejector block and then is connected with the threaded connection hole of the paving male die, so that the ejector rod is propped against the ejector block, and the threaded rod pushes the paving male die to be separated from the part forming body through rotating the threaded wrench, so that demolding is completed;

s7: and (3) part detection:

performing nondestructive inspection on the part molded body;

s8: trimming parts:

and (3) processing and trimming the part forming body according to related technical conditions to obtain the slender carbon fiber composite square tube structural member.

2. The method for manufacturing the square tube structural member made of the slender carbon fiber composite material according to claim 1, wherein the method comprises the following steps: the molded surface of the equalizing plate molding die expands 0.12mm on the basis of the outer surface of the carbon fiber square tube part.

3. The method for manufacturing the square tube structural member made of the slender carbon fiber composite material according to claim 1, wherein the method comprises the following steps: the combined surface of the left half pressure equalizing plate and the right half pressure equalizing plate is a stepped combined surface.

4. A method of making an elongated carbon fiber composite square tube structural member according to claim 3, wherein: the upper surface of half equalizing plate in left side is equipped with first outer concave station, and the lower surface is equipped with first concave station, the upper surface of half equalizing plate in right side be equipped with first outer concave station complex second concave station, the lower surface be equipped with first concave station matched second outer concave station.

5. The method for manufacturing the square tube structural member made of the slender carbon fiber composite material according to claim 1, wherein the method comprises the following steps: and S3, the thickness of the flange is 1.5-2.5 times of that of the square tube structural member made of the slender carbon fiber composite material.

6. The method for manufacturing the square tube structural member made of the slender carbon fiber composite material according to claim 1, wherein the method comprises the following steps: the length of the threaded rod is 1100mm, and the diameter of the threaded rod is 20mm.

Images