Forming preparation method of light high-strength composite material joint

Abstract

The invention relates to a forming preparation method of a light high-strength composite material joint, which is characterized by comprising the following steps of: 1, disassembling a hot-pressing mold, and cleaning the hot-pressing mold; secondly, the hot-pressing mold is assembled, and the surface of a formed cavity is evenly coated with a release agent; step 3, tearing and loosening the chopped fiber epoxy premix and weighing the chopped fiber epoxy premix according to the use weight; step 4, cutting the carbon fiber epoxy plain prepreg cloth and the carbon fiber epoxy unidirectional prepreg cloth according to the blanking drawing, and numbering the cut carbon fiber epoxy plain prepreg cloth and the cut carbon fiber epoxy unidirectional prepreg cloth; 5, the cut carbon fiber epoxy plain prepreg cloth pieces are evenly laid in a cavity of a mold, and the surfaces of a male mold cavity and a female mold cavity of the mold need to be laid; and the problems of blanking and paving during paving and forming of a large variable cross-section composite material product are solved.

Description

Technical Field

[0001] The invention belongs to the field of composite materials, and in particular relates to a method for forming and preparing a lightweight and high-strength composite material joint. Background Art

[0002] With the rapid development of aerospace technology, lightweight weapons and equipment, shortened delivery cycles and low costs have become a trend. For rocket engine shells, they are mainly composed of cylinders, heads, joints and other structures. As an important link in the development of engine shells, the performance of joints directly affects the performance of engine shells. At present, engine joints are mainly processed by aluminum alloy forgings, which have the problems of heavy weight and complex processing. At the same time, with the obvious trend of composite materials for shells, there will be interface problems and thermal expansion mismatch between metal joints and composite shells. Composite materials for joints can effectively reduce engine weight, reduce machining, and solve the problem of mismatch with shell materials. However, the traditional carbon fiber resin-based composite material paving molding process has problems such as long paving cycle, large paving molding quality deviation, unstable molding quality, low molding efficiency of some complex joints, large processing volume, and high manufacturing cost. Summary of the invention

[0003] The purpose of the present invention is to provide a method for forming and preparing a lightweight and high-strength composite material joint, so as to overcome the problems of low joint yield, heavy weight and long preparation cycle in the prior art, so that the joint product has a smoother surface, lower density and excellent mechanical properties.

[0004] A method for forming and preparing a lightweight and high-strength composite material joint, characterized in that it comprises the following steps:

[0005] Step 1: disassemble the hot pressing mold and clean it;

[0006] Step 2: Assemble the hot pressing mold and evenly apply a release agent to the surface of the molded cavity;

[0007] Step 3, tearing up the chopped fiber epoxy premix and weighing it according to the usage weight;

[0008] Step 4: Cut the carbon fiber epoxy plain weave prepreg and the carbon fiber epoxy unidirectional prepreg according to the cutting drawing and number them;

[0009] Step 5: Evenly lay the cut carbon fiber epoxy plain prepreg fabric pieces in the mold cavity, and both the male and female mold cavity surfaces of the mold need to be laid;

[0010] Step 6: Evenly lay the cut carbon fiber epoxy unidirectional prepreg in the mold, and lay the unidirectional prepreg on top of the plain prepreg in the female mold cavity and on top of the plain prepreg in the male mold cavity;

[0011] Step 7: Evenly spread the weighed chopped fiber epoxy premix in the mold, and lay the chopped fiber epoxy premix on top of the unidirectional prepreg;

[0012] Step 8: Close the hot pressing mold on the hot pressing machine, set the hot pressing temperature, curing pressure and holding time;

[0013] Step 9: After the heat preservation on the hot press is completed, the hot pressing mold is opened and the product is taken out;

[0014] Step 10: Finally, the product is subjected to post-processing such as deburring to obtain the product;

[0015] Among them, the hot pressing mold described in step one is a mold for hot pressing and curing the prepreg and premix uniformly laid in a certain order in the mold cavity into a product.

[0016] In step three, the premix is ​​a mixture of epoxy resin and chopped carbon fibers, the carbon fibers are T700 fibers, the carbon fibers have a length of 24 mm to 36 mm, and the resin content is 33% to 39%.

[0017] In step 4, the carbon fiber epoxy plain weave prepreg is a prepreg obtained by uniformly impregnating carbon fiber plain weave fabric with epoxy resin, the carbon fiber is T700 fiber, and the resin content is 33%-39%.

[0018] In step 4, the carbon fiber epoxy unidirectional prepreg is a prepreg obtained by uniformly impregnating the carbon fiber unidirectional tape with epoxy resin, the carbon fiber is T700 fiber, and the resin content is 33%-39%.

[0019] As described in step five, the cut carbon fiber epoxy plain prepreg fabric pieces are evenly laid in the mold cavity, and both the male and female mold cavity surfaces of the mold need to be laid.

[0020] In step six, the cut carbon fiber epoxy unidirectional prepreg is evenly laid in the mold, and the unidirectional prepreg is laid above the plain prepreg in the female mold cavity and above the plain prepreg in the male mold cavity.

[0021] As described in step seven, the weighed chopped fiber epoxy premix is ​​evenly spread in the mold. The chopped fiber epoxy premix needs to be spread on top of the female mold unidirectional prepreg cloth.

[0022] In step eight, the hot pressing temperature is 170° C.-180° C., the heat preservation time is 2 h-5 h, and the hot pressing pressure is 10 MPa-15 MPa.

[0023] Features and advantages of the present invention:

[0024] The present invention changes the current situation of traditional metal material joints and casting molding products with low main body yield, heavy weight and long molding cycle. The joints are molded and prepared by using carbon fiber reinforced resin-based composite materials, which reduces product weight, improves the yield of parts and shortens the entire product preparation cycle. In addition, the chopped fiber premix and continuous fiber prepreg materials are used together, which not only takes advantage of the higher strength of the continuous fibers but also introduces the good flow characteristics of the chopped fiber premix during the molding process, thus solving the internal quality problems such as high porosity of the product after complex surface paving and molding. The present invention also solves the difficulties in cutting and paving when paving and molding composite products with larger variable cross-sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a flow chart of an embodiment of the present invention;

[0026] Figure 2 It is the performance of the lightweight and high-strength composite material joint part made according to the embodiment of the invention.

[0027] Figure 3 It is a cross-sectional view of a carbon fiber reinforced resin-based composite material joint according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] The present invention is a method for forming and preparing a lightweight and high-strength composite material joint, which comprises the following steps:

[0029] S1. Disassemble and clean the hot pressing mold;

[0030] S2. Assemble the hot pressing mold and evenly apply a release agent to the surface of the molded cavity;

[0031] S3. The chopped fiber epoxy premix is ​​torn loose and weighed according to the use weight;

[0032] S4. The carbon fiber epoxy plain weave prepreg and the carbon fiber epoxy unidirectional prepreg are cut and numbered according to the cutting diagram;

[0033] S5. Evenly lay the cut carbon fiber epoxy plain prepreg fabric sheets in the mold cavity, and both the male and female mold cavity surfaces of the mold need to be laid;

[0034] S6. The cut carbon fiber epoxy unidirectional prepreg is evenly laid in the mold, and the unidirectional prepreg is laid on top of the plain weave prepreg in the female model cavity and on top of the plain weave prepreg in the male model cavity;

[0035] S7. The weighed chopped fiber epoxy premix is ​​evenly spread in the mold, and the chopped fiber epoxy premix is ​​laid on top of the unidirectional prepreg;

[0036] S8. The hot pressing mold is molded on the hot pressing machine, and the hot pressing temperature, curing pressure and holding time are set;

[0037] S9. After the hot pressing mold is kept warm on the hot pressing machine, the mold is opened and the product is taken out;

[0038] S10. Finally, the product is subjected to post-processing such as deburring to obtain the product;

[0039] In step S1, the hot pressing mold is used to hot press and solidify the prepreg and premix uniformly laid in a certain order in the mold cavity into a product.

[0040] The premix in step S3 is a mixture of epoxy resin and chopped carbon fibers, the carbon fibers are T700 fibers, and the resin content is 33%-39%.

[0041] The carbon fiber epoxy plain weave prepreg in step S4 is a prepreg obtained by uniformly impregnating carbon fiber plain weave fabric with epoxy resin, the carbon fiber is T700 fiber, and the resin content is 33%-39%.

[0042] The carbon fiber epoxy unidirectional prepreg in step S4 is a prepreg obtained by uniformly impregnating carbon fiber unidirectional tape with epoxy resin, the carbon fiber is T700 fiber, and the resin content is 33%-39%.

[0043] In step S5, the cut carbon fiber epoxy plain weave prepreg fabric pieces are evenly laid in the mold cavity of the mold, and both the male and female mold cavity surfaces of the mold need to be laid.

[0044] In step S6, the cut carbon fiber epoxy unidirectional prepreg is evenly laid in the mold, and the unidirectional prepreg is laid above the plain weave prepreg in the female mold cavity and above the plain weave prepreg in the male mold cavity.

[0045] In the step S7, the weighed chopped fiber epoxy premix is ​​evenly spread in the mold, and the chopped fiber epoxy premix needs to be spread on top of the unidirectional prepreg;.

[0046] In step S8, the hot pressing temperature is 170° C.-180° C., the holding time is 2 h-5 h, and the hot pressing pressure is 10 MPa-15 MPa.

[0047] Example:

[0048] The present invention can be better understood according to the following examples. However, the contents described in this embodiment are only used to illustrate the present invention, and should not and will not limit the present invention described in the claims.

[0049] The forming process of a certain type of joint. The forming process is as follows:

[0050] S1. Disassemble and clean the hot pressing mold;

[0051] S2. Assemble the hot pressing mold and evenly apply a release agent to the surface of the molded cavity;

[0052] S3. The chopped fiber epoxy premix is ​​torn loose and weighed according to the use weight;

[0053] S4. The carbon fiber epoxy plain weave prepreg and the carbon fiber epoxy unidirectional prepreg are cut and numbered according to the cutting diagram;

[0054] S5. Evenly lay the cut carbon fiber epoxy plain prepreg fabric sheets in the mold cavity, and both the male and female mold cavity surfaces of the mold need to be laid;

[0055] S6. The cut carbon fiber epoxy unidirectional prepreg is evenly laid in the mold, and the unidirectional prepreg is laid on top of the plain weave prepreg in the female model cavity and on top of the plain weave prepreg in the male model cavity;

[0056] S7. The weighed chopped fiber epoxy premix is ​​evenly spread in the mold, and the chopped fiber epoxy premix is ​​laid on top of the unidirectional prepreg;

[0057] S8. The hot pressing mold is molded on the hot pressing machine, and the hot pressing temperature, curing pressure and holding time are set;

[0058] S9. After the hot pressing mold is kept warm on the hot pressing machine, the mold is opened and the product is taken out;

[0059] S10. Finally, the product is subjected to post-processing such as deburring to obtain the product;

[0060] In step S1, the hot pressing mold is used to hot press and solidify the prepreg and premix uniformly laid in a certain order in the mold cavity into a product.

[0061] The premix in step S3 is a mixture of epoxy resin and chopped carbon fibers, the carbon fibers are T700 fibers, the length of the carbon fibers is 24 mm-36 mm, and the resin content is 33%-39%.

[0062] The carbon fiber epoxy plain weave prepreg in step S4 is a prepreg obtained by uniformly impregnating carbon fiber plain weave fabric with epoxy resin, the carbon fiber is T700 fiber, and the resin content is 33%-39%.

[0063] The carbon fiber epoxy unidirectional prepreg in step S4 is a prepreg obtained by uniformly impregnating carbon fiber unidirectional tape with epoxy resin, the carbon fiber is T700 fiber, and the resin content is 33%-39%.

[0064] In step S5, the cut carbon fiber epoxy plain weave prepreg fabric pieces are evenly laid in the mold cavity of the mold, and both the male and female mold cavity surfaces of the mold need to be laid.

[0065] In step S6, the cut carbon fiber epoxy unidirectional prepreg is evenly laid in the mold, and the unidirectional prepreg is laid above the plain weave prepreg in the female mold cavity and above the plain weave prepreg in the male mold cavity.

[0066] In the step S7, the weighed chopped fiber epoxy premix is ​​evenly spread in the mold, and the chopped fiber epoxy premix needs to be spread on top of the unidirectional prepreg;.

[0067] In step S8, the hot pressing temperature is 170° C.-180° C., the holding time is 2 h-5 h, and the hot pressing pressure is 10 MPa-15 MPa.

Claims

1. A method for forming and preparing a lightweight and high-strength composite material joint, characterized in that: The following steps are involved: Step 1: disassemble the hot pressing mold and clean it; Step 2: Assemble the hot pressing mold and evenly apply a release agent to the surface of the molded cavity; Step 3, tearing up the chopped fiber epoxy premix and weighing it according to the usage weight; Step 4: Cut the carbon fiber epoxy plain weave prepreg and the carbon fiber epoxy unidirectional prepreg according to the cutting drawing and number them; Step 5: Evenly lay the cut carbon fiber epoxy plain prepreg fabric pieces in the mold cavity, and both the male and female mold cavity surfaces of the mold need to be laid; Step 6: Evenly lay the cut carbon fiber epoxy unidirectional prepreg in the mold, and lay the unidirectional prepreg on top of the plain prepreg in the female mold cavity and on top of the plain prepreg in the male mold cavity; Step 7: Evenly spread the weighed chopped fiber epoxy premix in the mold, and lay the chopped fiber epoxy premix on top of the unidirectional prepreg; Step 8: Close the hot pressing mold on the hot pressing machine, set the hot pressing temperature, curing pressure and holding time; Step 9: After the heat preservation on the hot press is completed, the hot pressing mold is opened and the product is taken out; Step 10: Finally, the product is subjected to post-processing such as deburring to obtain the product.

2. A method for forming and preparing a lightweight and high-strength composite material joint according to claim 1, characterized in that: In step 1, the hot pressing mold is a mold for hot pressing and curing the prepreg and premix uniformly laid in a certain order in the mold cavity into a product.

3. A method for forming and preparing a lightweight and high-strength composite material joint according to claim 1, characterized in that: In step three, the premix is ​​a mixture of epoxy resin and chopped carbon fibers, the carbon fibers are T700 fibers, the carbon fibers have a length of 24 mm to 36 mm, and the resin content is 33% to 39%.

4. A method for forming and preparing a lightweight and high-strength composite material joint according to claim 1 or 3, characterized in that: In step 4, the carbon fiber epoxy plain weave prepreg is a prepreg obtained by uniformly impregnating carbon fiber plain weave fabric with epoxy resin, the carbon fiber is T700 fiber, and the resin content is 33%-39%.

5. A method for forming and preparing a lightweight and high-strength composite material joint according to claim 1 or 3, characterized in that: In step 4, the carbon fiber epoxy unidirectional prepreg is a prepreg obtained by uniformly impregnating the carbon fiber unidirectional tape with epoxy resin, the carbon fiber is T700 fiber, and the resin content is 33%-39%.

6. A method for forming and preparing a lightweight and high-strength composite material joint according to claim 1 or 3, characterized in that: As described in step five, the cut carbon fiber epoxy plain prepreg fabric pieces are evenly laid in the mold cavity, and both the male and female mold cavity surfaces of the mold need to be laid.

7. A method for forming and preparing a lightweight and high-strength composite material joint according to claim 1 or 3, characterized in that: In step six, the cut carbon fiber epoxy unidirectional prepreg is evenly laid in the mold, and the unidirectional prepreg is laid above the plain prepreg in the female mold cavity and above the plain prepreg in the male mold cavity.

8. A method for forming and preparing a lightweight and high-strength composite material joint according to claim 1 or 3, characterized in that: As described in step seven, the weighed chopped fiber epoxy premix is ​​evenly spread in the mold. The chopped fiber epoxy premix needs to be spread on top of the female mold unidirectional prepreg cloth.

9. A method for forming and preparing a lightweight and high-strength composite material joint according to claim 1 or 3, characterized in that: In step eight, the hot pressing temperature is 170° C.-180° C., the heat preservation time is 2 h-5 h, and the hot pressing pressure is 10 MPa-15 MPa.

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