CN-121989475-A - Preparation method of heat shield bracket

CN121989475ACN 121989475 ACN121989475 ACN 121989475ACN-121989475-A

Abstract

The invention relates to the technical field of composite material preparation, and particularly provides a preparation method of a heat shield bracket, which comprises the following steps: the method comprises the steps of preparing prepreg by using a carbon fiber reinforced phthalonitrile resin composite material, cutting the prepreg according to a heat shield support to form a net-size sample plate, manufacturing a forming die of the heat shield support, wherein the forming die is provided with a limiting device, limiting a split female die closing gap by using the limiting device, laying the net-size sample plate at a male die cavity position of the forming die, cold-closing the forming die, limiting the split female die closing gap by using the limiting device, heating and preserving the heat of the forming die after cold-closing, performing hot-closing operation on the forming die after removing the limiting device, and demoulding after solidification. The cold die clamping limiting device and the pressurizing conversion device are added in the molding process of the method, so that the quick pressurizing of the hot die is realized, the problems of low viscosity of resin and narrow process window are overcome, and the high-temperature-resistant heat shield bracket with high dimensional accuracy and no internal quality defect is manufactured.

Inventors

ZOU ZHIWEI
DONG ZHIWU
LI YULONG
SONG QINGNAN
Lv Fukuan

Assignees

长春长光宇航复合材料有限公司

Dates

Publication Date: 20260508
Application Date: 20260206

Claims (10)

1. A method of making a heat shield mount comprising: S1, preparing prepreg by using a composite material, and cutting the prepreg according to the shape of a heat shield bracket to form a net-size sample plate; S2, manufacturing a forming die of the heat shield bracket, wherein the forming die is provided with a limiting device, and a split female die closing gap can be limited by the limiting device; s3, paving the net-size sample plate at the cavity position of a male die of a forming die; s4, cold-closing the forming die, and limiting a die-closing gap of the split female die by using the limiting device; s5, after the limiting device is removed, performing hot-die assembly operation on the forming die, solidifying and demolding.
2. The method for manufacturing a heat shield support according to claim 1, wherein in S4, the fiber cloth of the composite material is M40-grade 6K carbon cloth 40TW-6011, and the resin matrix is phthalonitrile resin.
3. The method of claim 2, wherein the net-size sample plate material has the same characteristic dimensions as the heat shield support, and the warp and weft directions of the fiber cloth are consistent with the design direction.
4. The method for manufacturing a heat shield support according to claim 1, wherein the forming die further comprises a pressurizing direction conversion device arranged at the outermost side of the forming die, the limiting device comprises a limiting plate and a plurality of limiting nails penetrating through the outer edge of the limiting plate along the circumferential direction, the limiting nails are rotated to adjust the length of the limiting nails extending out of the upper surface of the limiting plate, the upper surfaces of the limiting nails are contacted with the pressurizing direction conversion device to limit the position of the pressurizing direction conversion device so as to adjust the split female die closing gap, and the limiting device is removed when the viscosity of resin overflowed from the split female die closing gap is between 10000mpa.s and 30000mpa.s and cannot be freely dripped after dipping.
5. A method of making a heat shield support according to claim 4 wherein said pressurizing direction conversion means moves downwardly to drive said split female mold toward said male mold.
6. The method of manufacturing a heat shield support of claim 1, wherein the split female mold closing gap is between 0.2mm and 0.4mm during cold mold closing, and the split female mold closing gap is not higher than 0.1mm during hot mold closing.
7. The method of claim 6, wherein S3 further comprises depositing a sacrificial layer prepreg at a location on the male mold cavity corresponding to a particular outer surface, the particular outer surface comprising an outer surface of the heat shield support having a desired flatness or being a mounting surface.
8. A method of making a heat shield support according to claim 6 wherein the sacrificial layer prepreg is used to process to form the special outer surface, the sacrificial layer prepreg having a thickness of between 0.5mm and 2 mm.
9. The method of preparing a heat shield support according to claim 1 wherein the net-size sample sheet is laid at a lay-up angle of [ ±45]4s.
10. The method of claim 1, wherein the curing system of the curing in S5 comprises at least two steps of 250 ℃ to 275 ℃ per 4h to 350 ℃ per 4h.

Description

Preparation method of heat shield bracket Technical Field The invention relates to the technical field of composite material preparation, and particularly provides a preparation method of a heat shield bracket. Background In the fields of aerospace and high-end industry, high-temperature protection systems are core components that ensure the stable operation of critical equipment in extreme environments. Taking rocket engine jet pipe as an example, extremely high temperature and hot air flow can be formed during operation, and in order to avoid damage to peripheral structures caused by heat, a heat shield is usually installed at the outer side of the jet pipe for heat isolation. The heat shield support serves as a key bearing structure for mounting the heat shield. It is not only to bear the weight of the heat shield and itself, but also to bear complex alternating mechanical loads during vectoring of the nozzle, and to maintain structural integrity and dimensional stability in high temperature environments above 300 ℃. At present, three main types of heat shield support for spray pipes are prepared. Firstly, a metal material precision casting scheme is adopted, and a high-temperature alloy material or a magnesium alloy material with lower density is usually selected. However, the weight of the heat shield support prepared by the scheme is difficult to meet the increasingly severe weight reduction requirements, and the payload of the rocket is affected. Secondly, preparing a heat shield bracket of the carbon fiber reinforced carbon-based composite material (C/C) or the carbon fiber reinforced silicon carbide composite material (C/SiC) by using a carbon fiber preform and a chemical vapor infiltration or liquid impregnation scheme. However, the scheme has the problems of complex process, long preparation period and high cost, the brittleness of the material is high, the impact load in the swinging process of the spray pipe is difficult to bear, and the reliability of the material is poor. Thirdly, preparing the structural member by adopting carbon fiber reinforced high-temperature-resistant resin matrix (phthalonitrile) composite material prepreg. At present, the method is mostly used for producing simple structural members, such as flat products, simple cabin products and the like, and the preparation method has the characteristic of customizing specific products, and has higher molding operation difficulty. Because the heat screen support has the characteristics of high weight reduction requirement and complex structure, the currently disclosed preparation process method cannot meet the requirements of heat screen support products on internal quality and dimensional accuracy, and is not applied to the field. Based on the above technical background, the existing heat shield support material selection and manufacturing process greatly limit the application range and the limiting performance of the product, so that development of a heat shield support preparation method with low cost, light weight and reliable process is urgently needed. Disclosure of Invention The invention provides a preparation method of a heat shield bracket, which adopts high-temperature-resistant prepreg, adds a cold die clamping limiting device in the forming process, and rapidly pressurizes a hot die, so that the process is simplified, and the obtained heat shield bracket has good strength and toughness, short period and low cost. The preparation method of the heat shield bracket provided by the invention comprises the following steps: S1, preparing prepreg by using a composite material, cutting the prepreg according to the shape of a heat shield bracket to form a net-size sample plate; S2, manufacturing a forming die of the heat shield bracket, wherein the forming die is provided with a limiting device, and a split female die closing gap can be limited by the limiting device; s3, paving a net-size sample plate at the cavity position of a male die of a forming die; s4, cold-closing the forming die, and limiting a die closing gap of the split female die by using a limiting device; s5, after the limiting device is removed, performing hot-die assembly operation on the forming die, solidifying and demolding. Preferably, in S4, the fiber cloth of the composite material is M40 grade 6K carbon cloth 40TW-6011, and the resin matrix is phthalonitrile resin. Preferably, the feature sizes of all parts of the net-size sample plate and the heat shield support are the same, and the warp and weft fiber directions of the fiber cloth are consistent with the design directions. Preferably, the forming die further comprises a pressurizing direction conversion device arranged at the outermost side of the forming die, the limiting device comprises a limiting plate and a plurality of limiting nails penetrating through the outer edge of the limiting plate along the circumferential direction, the limiting nails are rotated to adjust the lengths of the limiting